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1
Lock, A. L., and P. C. Garnsworthy. "Conjugated linoleic acid in cows milk: independent effects of dietary linoleic and linolenic fatty acids." Proceedings of the British Society of Animal Science 2001 (2001): 80. http://dx.doi.org/10.1017/s1752756200004622.
Анотація:
It is desirable to increase the level of conjugated linoleic acid (CLA) in milk as a health benefit in human nutrition. CLA has been shown to affect carcinogenesis, atherosclerosis, diabetes, the immune system, bone mineralization, body fat accretion and nutrient partitioning. The predominant CLA isomer present in foods from ruminants is cis-9, trans-11 CLA. It is formed in the rumen by anaerobic bacteria as an intermediate in the hydrogenation of linoleic acid. Recent evidence has shown that CLA can also be produced in the mammary gland by desaturation of trans-11 C18:1. Previous researchers have used various oils or oil seeds to try and elevate CLA levels in milk. A problem with this approach is that most oils contain mixtures of fatty acids so responses cannot be attributed to individual acids. Up to now there has been no report looking at how individual fatty acids affect CLA production. The objective of this work was to separate the effects of linoleic and linolenic acids on CLA production in dairy cows.
2
Lock, A. L., and P. C. Garnsworthy. "Independent effects of dietary linoleic and linolenic fatty acids on the conjugated linoleic acid content of cows’ milk." Animal Science 74, no. 1 (February 2002): 163–76. http://dx.doi.org/10.1017/s1357729800052334.
Анотація:
AbstractIt may be desirable to increase the level of conjugated linoleic acid (CLA) in milk as a health benefit in human nutrition. The purpose of this work was to separate the effects of linoleic and linolenic acids on CLA production in dairy cows and to determine to what extent endogenous synthesis contributes to cis-9, trans-11 CLA concentration in milk fat. Eight lactating cows and four non-lactating duodenal fistulated cows were used in a 4 ✕ 4 Latin-square design. All cows received a basal diet of grass silage that was supplemented with one of four concentrates, which were designed to differ in their linoleic and linolenic acid contents. The oil components of the concentrates were produced from mixtures of olive, linseed, rape, soya and sunflower oils to produce the four treatments: low linoleic/ low linolenic acid (LL), low linoleic/high linolenic acid (LH), high linoleic/low linolenic acid (HL) and high linoleic/ high linolenic acid (HH). Milk cis-9, trans-11 CLA contents were 0·8, 0·9, 0·9 and 1·1 g/100 g fatty acid methyl esters (P < 0·05) and yields were 5, 7, 7 and 8 g/day (P < 0·05) for the LL, LH, HL and HH treatments, respectively. The yields of trans-C18:1 fatty acids in milk were 19, 22, 21 and 23 g/day (P < 0·05), respectively. Taking the data for the cis-9, trans-11 CLA content and flow of duodenal fluid from the fistulated cows and representing this in terms of dietary intake by the lactating animals, the amounts of cis-9, trans-11 CLA produced in the rumen were calculated to be 0·8, 0·9, 1·2 and 1·1 g/day (P < 0·05) and for trans-C18:1 fatty acids 58, 58, 66 and 69 g/day (P < 0·05). Increasing linoleic and/or linolenic acids in the diet can increase the cis-9, trans-11 CLA content of cows’ milk. Only diets high in linoleic acid increased cis-9, trans-11 CLA production in the rumen. On all four diets, more than 80% of cis-9, trans-11 CLA in milk was produced endogenously by Δ9-desaturase from trans-11 C18:1 in the mammary gland. Cows on the same diet have different milk fat cis-9, trans-11 CLA concentrations that may be partially explained by differences in Δ9-desaturase activity between cows. Increasing the activity of Δ9-desaturase in the mammary gland may offer greater potential for enhancing the cis-9, trans-11 CLA content of milk fat than increasing cis-9, trans-11 CLA production in the rumen.
3
Turpeinen, Anu M., Sonja Bärlund, Riitta Freese, Peter Lawrence, and Thomas Brenna. "Effects of conjugated linoleic acid on linoleic and linolenic acid metabolism in man." British Journal of Nutrition 95, no. 4 (April 2006): 727–33. http://dx.doi.org/10.1079/bjn20051432.
Анотація:
Evidence from animal studies suggests that conjugated linoleic acid (CLA) modulates plasma and tissue appearance of newly synthesized PUFA. The effects of a 1·2g (0·5% energy) daily intake of the cis-9, trans-11 (c9, t11) isomer of CLA, trans-10,cis-12 (t10, c12) isomer of CLA or olive oil (placebo) on linoleic acid (LA) and linolenic acid (LNA) metabolism in healthy human volunteers was investigated. Fifteen subjects were fed an experimental diet and supplemented with c9,t11-CLA, t10, c12-CLA or placebo for 7d before consuming a tracer dose of U-[13C]La (50%Mg) And U-[13C]Lna (50Mg). Blood Samples Were Taken At 0, 2, 4, 6, 8, 24, 48, 72 and 168%h and analysed using high-precision MS. No differences between the groups in peak plasma [13C]LA (10·3–11·6% of dose), [13C]LNA (2·5–2·9% of dose), [13C]arachidonic acid (0·09–0·12% of dose), [13C]EPA (0·04–0·06% of dose) or [13C]Dha (0c·06–0·10% of dose) were detected. Concentration V. time curves (area under the curve) also showed no significant differences between groups. This suggests that, in healthy human subjects consuming a diet with adequate intake of essential fatty acids, CLA does not affect metabolism of LA or LNA
4
Jenkins, Julie K., and Polly D. Courtney. "Lactobacillusgrowth and membrane composition in the presence of linoleic or conjugated linoleic acid." Canadian Journal of Microbiology 49, no. 1 (January 1, 2003): 51–57. http://dx.doi.org/10.1139/w03-003.
Анотація:
Five Lactobacillus strains of intestinal and food origins were grown in MRS broth or milk containing various concentrations of linoleic acid or conjugated linoleic acid (CLA). The fatty acids had bacteriostatic, bacteriocidal, or no effect depending on bacterial strain, fatty acid concentration, fatty acid type, and growth medium. Both fatty acids displayed dose-dependent inhibition. All strains were inhibited to a greater extent by the fatty acids in broth than in milk. The CLA isomer mixture was less inhibitory than linoleic acid. Lactobacillus reuteri ATCC 55739, a strain capable of isomerizing linoleic acid to CLA, was the most inhibited strain by the presence of linoleic acid in broth or milk. In contrast, a member of the same species, L. reuteri ATCC 23272, was the least inhibited strain by linoleic acid and CLA. All strains increased membrane linoleic acid or CLA levels when grown with exogenous fatty acid. Lactobacillus reuteri ATCC 55739 had substantial CLA in the membrane when the growth medium was supplemented with linoleic acid. No association between level of fatty acid incorporation into the membrane and inhibition by that fatty acid was observed.Key words: Lactobacillus, conjugated linoleic acid, linoleic acid, cell membrane.
5
Dachev, Marko, Jana Bryndová, Milan Jakubek, Zdeněk Moučka, and Marian Urban. "The Effects of Conjugated Linoleic Acids on Cancer." Processes 9, no. 3 (March 3, 2021): 454. http://dx.doi.org/10.3390/pr9030454.
Анотація:
Conjugated linoleic acids (CLA) are distinctive polyunsaturated fatty acids. They are present in food produced by ruminant animals and they are accumulated in seeds of certain plants. These naturally occurring substances have demonstrated to have anti-carcinogenic activity. Their potential effect to inhibit cancer has been shown in vivo and in vitro studies. In this review, we present the multiple effects of CLA isomers on cancer development such as anti-tumor efficiency, anti-mutagenic and anti-oxidant activity. Although the majority of the studies in vivo and in vitro summarized in this review have demonstrated beneficial effects of CLA on the proliferation and apoptosis of tumor cells, further experimental work is needed to estimate the true value of CLA as a real anti-cancer agent.
6
Ostrowska, Ewa, Reg F. Cross, Morley Muralitharan, Dale E. Bauman, and Frank R. Dunshea. "Dietary conjugated linoleic acid differentially alters fatty acid composition and increases conjugated linoleic acid content in porcine adipose tissue." British Journal of Nutrition 90, no. 5 (November 2003): 915–28. http://dx.doi.org/10.1079/bjn2003982.
Анотація:
Conjugated linoleic acids (CLA) have been shown to decrease body fat content in pigs. It is possible that feeding pigs diets rich in CLA may increase carcass lipid CLA to levels that could provide health benefits when included as a part of a healthy diet. Therefore, the aim of the present study was to determine whether dietary CLA supplementation has any effect on the fatty acid composition of subcutaneous and intramuscular adipose tissue in pigs. Thirty-five female cross bred (Large White×Landrace) pigs (initial weight 57·2kg and initial P2 back fat 11·5mm) were used in the present study. Pigs were housed individually and randomly allocated to one of six dietary treatments (0·00, 1·25, 2·50, 5·00, 7·50 and 10·00g CLA55 (55g CLA isomers/100g total fatty acids; Natural Lipids Ltd, Hovdebygda, Norway)/kg) and fed their respective diets for 8 weeks. Twelve CLA isomers in the diet and in pig tissue lipids were separated by Ag+-HPLC. CLA was incorporated at fivefold higher levels in subcutaneous fat as compared with intramuscular fat and in a dose-dependant manner. Overall, the transfer efficiency of CLA was maximized at 5·00g CLA55/kg. However, there was clear selectivity in the uptake or incorporation ofcis,trans-9,11 isomer over thetrans,cis-10,12 isomer. In general, CLA supplementation produced significant changes in skeletal muscle and adipose tissue fatty acid composition, indicating that dietary CLA had a potent affect on lipid transport and metabolismin vivo. Significant increases in myristic, palmitic and palmitoleic acids and a reduction in arachidonic acid were observed, suggesting an alteration in activity of Δ5-, Δ6- and Δ9-desaturases in pig adipose tissue. In conclusion, feeding pigs diets supplemented with CLA increases carcass lipid CLA, but also results in changes in the fatty acid profile in pig fat that could potentially outweigh the benefits of CLA.
7
Vaclavkova, E., Z. Volek, J. Belkova, D. Duskova, M. Czauderna, and M. Marounek. "Effect of linseed and the combination of conjugated linoleic acid and linseed on the quality and oxidative stability of pig meat and subcutaneous fat." Veterinární Medicína 61, No. 8 (March 10, 2017): 428–35. http://dx.doi.org/10.17221/117/2015-vetmed.
Анотація:
The aim of this experiment was to test the hypothesis that conjugated linoleic acid (CLA) in diets of finishing pigs fed linseed can improve the quality and oxidative stability of meat and subcutaneous fat. Twenty-four Prestice Black-Pied pigs (barrows and gilts) were divided into three groups and were fed a basal diet and diets supplemented with ground linseed (70 g/kg), or linseed combined with conjugated linoleic acid (20 g CLA-oil/kg). The trial duration was 53 days. Measurements included slaughter and meat quality parameters, oxidative stability determination, and fatty acid profile of meat and subcutaneous fat. The experimental data were analysed using one-way analysis of variance. Neither linseed nor linseed with CLA significantly influenced weight gain, lean percentage, muscle depth, backfat thickness, drip loss, meat shear force, dry matter, intramuscular fat or cholesterol (P > 0.05). Dietary supplementation with linseed increased the percentage of linolenic acid in the fatty acids of meat and backfat and resulted in higher production of aldehydes. Dietary CLA did not influence the susceptibility of lipids to oxidation. Supplementation with CLA significantly increased CLA proportions in fatty acids of meat and backfat, reduced proportions of monounsaturated fatty acids, and increased proportions of saturated fatty acids in backfat (P < 0.05). The concentration of CLA (in mg/100 g of fresh tissue) in backfat was almost fifty times higher than in meat. Both meat and backfat of pigs fed CLA-free diets contained CLA, probably as a result of microbial conversion of linoleic acid in the intestine. It can be concluded that CLA changed the fatty acid profile of meat and backfat, but did not improve oxidative stability and other meat quality traits of pigs fed linseed.
8
Yari, Pouya, Abbas Moazami Goudarzi, Mansour Ahmadi, Jalal Masoumi, and Somayeh Kamran Azad. "Influences of Conjugated Linoleic Acid on Poultry Products." International Journal of Life Sciences 9, no. 4 (June 5, 2015): 1–5. http://dx.doi.org/10.3126/ijls.v9i4.12676.
Анотація:
Conjugated linoleic acid (CLA) has a potential role in the prevention of cancer tumors of the skin, breast, stomach and intestine. CLA also has the ability to prevent cardiovascular disease, atherosclerotic disease, diabetes, regulation of immune responses and change in body composition by reducing body fat. Fats that originated from the ruminants are the main sources of CLA. But poultry products are contain traces of these fatty acids. Fatty acids content in monogastric diets did not change after digestion and absorption, compared with ruminants. So use of synthetic CLA or its precursors, can increase the synthesis and save of this fatty acid in poultry products. After absorption, the CLA or its resources, are stored in phospholipids of call membrane, fatty tissue and eggs. Therefore attempts to enrich poultry production via CLA as an appropriate method for improving human nutrition by organic sources, will cause the useful results.DOI: http://dx.doi.org/10.3126/ijls.v9i4.12676
9
Acosta Balcazar, Isabel Cristina, Lorenzo Danilo Granados Rivera, Jaime Salinas Chavira, Benigno Estrada Drouaillet, Miguel Ruiz Albarrán, and Yuridia Bautista Martínez. "Relationship between the Composition of Lipids in Forages and the Concentration of Conjugated Linoleic Acid in Cow’s Milk: A Review." Animals 12, no. 13 (June 24, 2022): 1621. http://dx.doi.org/10.3390/ani12131621.
Анотація:
Conjugated linoleic acid (CLA), has been shown to have protective effects against various diseases, such as obesity, arteriosclerosis, diabetes, chronic inflammatory diseases, and cancer. This fatty acid in ruminants results from two processes, biohydrogenation, which takes place in the rumen, and de novo synthesis, carried out in the mammary gland, and it has linoleic and α-linolenic acids as its precursors. The amounts of precursors in the diets of animals are related to the amounts of CLA in milk. In the literature review, it was found that the milk of cows fed fresh forage has a higher amount of CLA because they have a higher amount of linoleic acid and α-linolenic acid compared to other foods used in the diets of cows. The amount of CLA precursors in pastures can be increased through agronomic practices, such as nitrogen fertilization, and regrowth age. It is also a technique used to increase the amount of CLA in milk to obtain a greater benefit regarding its nutritional value.
10
Mir, Z., L. J. Paterson, and P. S. Mir. "Fatty acid composition and conjugated linoleic acid content of intramuscular fat in crossbred cattle with and without Wagyu genetics fed a barley-based diet." Canadian Journal of Animal Science 80, no. 1 (March 1, 2000): 195–97. http://dx.doi.org/10.4141/a98-113.
Анотація:
Fatty acid composition and conjugated linoleic acid (CLA) content in pars costalis diaphragmatis (PCD) muscle from European and British crossbred (EBC; no Wagyu genetics) and Wagyu crossbred (WC; 75% Wagyu genetics) beef cattle were determined. Conjugated linoleic acid contents of PCD muscle from EBC (1.7 mg CLA g−1 lipid) and WC (1.8 mg CLA g−1 lipid) cattle were similar (P > 0.05), while WC cattle had higher (P < 0.05) CLA content 100 g−1 of beef on a DM basis because the lipid content of meat from WC cattle was greater (P < 0.05) than that from EBC cattle Key words: Conjugated linoleic acid, Wagyu, fatty acids, barley, beef cattle
11
Raimondi, Stefano, Alberto Amaretti, Alan Leonardi, Andrea Quartieri, Caterina Gozzoli, and Maddalena Rossi. "Conjugated Linoleic Acid Production by Bifidobacteria: Screening, Kinetic, and Composition." BioMed Research International 2016 (2016): 1–8. http://dx.doi.org/10.1155/2016/8654317.
Анотація:
Conjugated linoleic acids (CLA) are positional and geometric isomers of linoleic acid involved in a number of health aspects. In humans, CLA production is performed by gut microbiota, including some species of potential probiotic bifidobacteria. 128 strains of 31Bifidobacteriumspecies were screened with a spectrophotometric assay to identify novel CLA producers. Most species were nonproducers, while producers belonged toB. breveandB. pseudocatenulatum. GC-MS revealed that CLA producer strains yielded 9cis,11trans-CLA and 9trans,11trans-CLA, without any production of other isomers. Hydroxylated forms of LA were absent in producer strains, suggesting that the myosin-cross-reactive antigen (MCRA) protein that exerts hydratase activity is not involved in LA isomerization. Moreover, both CLA producer and nonproducer species bear a MCRA homologue. The strainB. breveWC 0421 was the best CLA producer, converting LA into 68.8% 9cis,11trans-CLA and 25.1% 9trans,11trans-CLA. Production occurred mostly during the lag and the exponential phase. For the first time, production and incorporation of CLA in biomass were assessed.B. breveWC 0421 stored CLA in the form of free fatty acids, without changing the composition of the esterified fatty acids, which mainly occurred in the plasmatic membrane.
12
Barrett, E., R. P. Ross, G. F. Fitzgerald, and C. Stanton. "Rapid Screening Method for Analyzing the Conjugated Linoleic Acid Production Capabilities of Bacterial Cultures." Applied and Environmental Microbiology 73, no. 7 (February 2, 2007): 2333–37. http://dx.doi.org/10.1128/aem.01855-06.
Анотація:
ABSTRACT In this paper we describe a rapid method for identifying bacteria which convert free linoleic acid to conjugated linoleic acid (CLA). This method is based on spectrophotometric detection of CLA and compares well with the standard gas-liquid chromatography method. This method should facilitate high-throughput screening of bacterial isolates for the ability to produce conjugated fatty acids.
13
Javadi, M., H. Everts, R. Hovenier, S. Kocsis, Æ. Lankhorst, A. G. Lemmens, J. Th Schonewille, A. H. M. Terpstra, and A. C. Beynen. "The effect of six different C18 fatty acids on body fat and energy metabolism in mice." British Journal of Nutrition 92, no. 3 (September 2004): 391–99. http://dx.doi.org/10.1079/bjn20041217.
Анотація:
We studied the effects of five high-fat semi-purified diets varying at a 4 % (w/w) level in either stearic, oleic, linoleic, α-linolenic, or γ-linolenic acid on body fat and energy metabolism in BALB/c mice. A diet containing caprylic, capric, lauric, and myristic acid was used as a reference diet and a diet with 4 % conjugated linoleic acid (CLA) was used as a positive control as it is known to effectively lower body fat in mice. The diets were fed for 35 d. Body fat was significantly lower in the CLA group than in the other groups but was not significantly different among the non-CLA groups. Among the non-CLA groups, the linoleic acid group tended to have the highest and the α-linolenic acid group the lowest proportion of body fat. In energy-balance studies, the percentage of energy intake that was stored in the body was significantly lower in the CLA group compared with the other dietary groups. The percentage of energy intake eliminated in excreta was highest in the stearic acid group followed by the γ-linolenic acid group. These results were reflected in apparent fat digestibility, which was lowest in the stearic acid group. The percentage of energy intake expended as heat was highest in the CLA-fed mice. The results of the present study suggest that body fat and energy accretion in mice fed diets containing different C18 fatty acids is by far the lowest with CLA and that linoleic acid produced the highest fat intake and energy accretion.
14
D'Orazio, N., C. Ficoneri, G. Riccioni, P. Conti, T. C. Theoharides, and M. R. Bollea. "Conjugated Linoleic Acid: A Functional Food?" International Journal of Immunopathology and Pharmacology 16, no. 3 (September 2003): 215–20. http://dx.doi.org/10.1177/039463200301600305.
Анотація:
Scientific interest in conjugated linoleic acid (CLA) started in 1987 when Michael Pariza's team of Wisconsin University observed its inhibitory effects on chemically induced skin tumors in mice. Numerous studies have since examined CLA's role in cancer, immune function, oxidative stress, atherosclerosis, lipid and fatty acids metabolism, bone formation and composition, obesity, and diabetes. Still it's not clear yet either through which mechanisms CLA produces its numerous metabolic effects. We now know that CLA contents in cow milk fat can be enriched through dry fractionation, but this knowledge doesn't allow sufficient certainty to qualify this nutrient, as a functional food, capable of increasing well being and reducing the risk of disease.
15
Mir, P. S., M. Ivan, M. L. He, B. Pink, E. Okine, L. Goonewardene, T. A. McAllister, R. Weselake, and Z. Mir. "Dietary manipulation to increase conjugated linoleic acids and other desirable fatty acids in beef: A review." Canadian Journal of Animal Science 83, no. 4 (December 1, 2003): 673–85. http://dx.doi.org/10.4141/a03-002.
Анотація:
The diet is the source of many essential fatty acids such as linoleic and linolenic acids for all mammals. These fatty acids either, as altered isomers or as other elongated products, have been found to provide unique advantages to human health. Currently two conjugated linoleic acids (CLA) isomers (cis-9, trans-11 C18:2; trans-10, cis-12 C18:2) and two elongated products of linolenic acid [eicosapentaenoic acid (EPA, C20:5 n-3), docosahexaenoic acid (DHA, C22:6 n-3)] have been recognized for their roles in maintaining human health. Consumers can obtain these functional fatty acids from beef if the feeding management of beef cattle can be altered to include precursor fatty acids. Diet, breed, and gender are important factors that affect total fat content and/or the fatty acid profile of beef with regard to CLA, EPA, and DHA. Diet provides the precursor fatty acids that are altered and deposited, and breed dictates, the amount of fat that is deposited. These fatty acids can be increased in beef by increasing the forage:concentrate ratio, inclusion of non-fermented forage, and supplementation with various oils or oil seeds. The CLA and vaccenic acid (trans-11 C18:1) concentration in beef was increased by feeding sunflower oil or seeds, linseed, and soybean oil supplemented diets, while cattle fed linseed and fish oil supplemented diets had increased concentrations of EPA and DHA. Although the concentration of these fatty acids can be increased in beef, there is a need to further the understanding of the mechanism by which they exert positive affects on human health. Key words: Cattle, beef, fatty acids, conjugated linoleic acid, eicosapentaenoic acid, docosahexaenoic acid
16
Białek, Agnieszka, Małgorzata Jelińska, Małgorzata Białek, Tomasz Lepionka, Małgorzata Czerwonka, and Marian Czauderna. "The Effect of Diet Supplementation with Pomegranate and Bitter Melon on Lipidomic Profile of Serum and Cancerous Tissues of Rats with Mammary Tumours." Antioxidants 9, no. 3 (March 17, 2020): 243. http://dx.doi.org/10.3390/antiox9030243.
Анотація:
The aim of this study was to present overall lipid profile of organisms with ongoing neoplastic process and applied diet supplementation with pomegranate seed oil (PSO) and bitter melon extract (BME). The following were quantified in serum and cancerous tissues of rats suffering from mammary tumours: fatty acids, conjugated fatty acids and sterols, their oxidised metabolites (malondialdehyde and oxysterols) and lipoxygenase (LOX) metabolites of polyunsaturated fatty acids. The obtained results indicate that abnormalities in lipid metabolism accompany neoplastic process. These differences concern all classes of lipids and most pathways of their transformation, with the special emphasis on lipid peroxidation and LOX-mediated metabolism. Cancer process appears to be so detrimental that it may conceal positive influence of dietary modifications. The lack of anticarcinogenic properties of PSO and BME in this model may be due to their antioxidant properties or elevated levels of conjugated linoleic acids (CLA), which change CLA isomer activity from anti- to pro-tumorigenic. As CLA are the product of conjugated linolenic acids (CLnA) endogenous metabolism, high CLA levels may be explained by applied diet enrichment.
17
Stinshoff, Hanna, Sandra Wilkening, Ana Hanstedt, Heinrich Bollwein, and Christine Wrenzycki. "Dimethylsulfoxide and conjugated linoleic acids affect bovine embryo development in vitro." Reproduction, Fertility and Development 26, no. 4 (2014): 502. http://dx.doi.org/10.1071/rd12372.
Анотація:
Conjugated linoleic acids (CLA) are employed to overcome the bovine periparturitional negative energy balance. Especially of interest are trans10,cis12 -linoleic acid (t10c12-CLA) and cis9,trans11-linoleic acid (c9t11-CLA). Their impact on embryonic development, though, is not clear. Here, effects of both above-mentioned CLA on bovine in vitro-produced embryos were assessed. Zygotes (n = 2098) were allocated to one of seven groups: cultured with 50 or 100 µM of either c9t11-CLA or t10c12-CLA, with 14 or 28 mM DMSO or without supplement (control). Messenger RNA analysis of target gene transcripts (IGF1R, IGFBP2, IGFBP4, CPT2, ACAA1, ACAA2, FASN, SCD) via RT-qPCR was performed in single blastocysts. Cleavage rates did not differ, whereas development rates were decreased in both t10c12-supplemented groups in comparison to the unsupplemented group (31.7% ± 2.2 control vs 20.2% ± 2.0 50 µM t10c12 vs 21.0% ± 2.8 100 µM t10c12). Compared with the unsupplemented group, SCD was expressed at a lower level in embryos cultured with 50 µM c9t11-CLA. The relative amount of several transcripts was increased in embryos cultured with 14 mM DMSO in comparison to those that developed in the presence of 50 µM t10c12-CLA (IGFBP2, ACAA1, CPT2, FASN, SCD) or 50 µM c9t11-CLA (IGF1R, IGFBP2, ACAA1, CPT2, FASN, SCD). The molecular analyses show that CLA influence embryonic fat metabolism.
18
Lawless, F., J. J. Murphy, S. Fitzgerald, B. O’Brien, R. Devery, and C. Stanton. "Dietary effect on bovine milk fat conjugated linoleic acid content." BSAP Occasional Publication 25 (2000): 283–93. http://dx.doi.org/10.1017/s1463981500040875.
Анотація:
AbstractConjugated linoleic acid (cis-9, trans-11-C18:2; CLA) in milk arises as a result of microbial biohydrogenation of dietary linoleic and linolenic acids in the rumen (Kepler and Tove, 1967). Milk fat CLA concentrations were significantly (P<0.05) higher when cows were fed silage supplemented with pulp’n brew (a mixture of brewers grains, a by-product of the brewing industry, and sugar beet pulp in dry matter proportions of 0.65:0.35), compared with silage alone (Trial 1). Intake of spring grass resulted in a 2.1–fold increase in milk fat CLA concentrations over cows receiving autumn grass. Throughout lactation in Trial 2, spring calving cows produced higher milk fat CLA concentrations (from 0.5-2.7 g/100 g fatty acid methyl esters (FAME)) than autumn calving cows (0.3-1.7 g/100 g FAME); the former having spent 80% and the latter 50% of lactation on pasture. The CLA content was higher in late lactation milk compared with early lactation milk in both herds. There were no significant differences in milk yields or milk constituent yields between the herds. Manufacturing milk obtained between March and September was analyzed for milk fatty acid composition and the data correlated with grass growth throughout the season. Significant positive correlations were obtained between grass growth rates and concentrations of CLA and linolenic acid in milk fat. The data indicate that seasonal variation in milk fat CLA concentrations may be attributed to variation in pasture growth rates.
19
Ogawa, Jun, Kenji Matsumura, Shigenobu Kishino, Yoriko Omura, and Sakayu Shimizu. "Conjugated Linoleic Acid Accumulation via 10-Hydroxy-12-Octadecaenoic Acid during Microaerobic Transformation of Linoleic Acid by Lactobacillus acidophilus." Applied and Environmental Microbiology 67, no. 3 (March 1, 2001): 1246–52. http://dx.doi.org/10.1128/aem.67.3.1246-1252.2001.
Анотація:
ABSTRACT Specific isomers of conjugated linoleic acid (CLA), a fatty acid with potentially beneficial physiological and anticarcinogenic effects, were efficiently produced from linoleic acid by washed cells ofLactobacillus acidophilus AKU 1137 under microaerobic conditions, and the metabolic pathway of CLA production from linoleic acid is explained for the first time. The CLA isomers produced were identified as cis-9, trans-11- ortrans-9, cis-11-octadecadienoic acid andtrans-9, trans-11-octadecadienoic acid. Preceding the production of CLA, hydroxy fatty acids identified as 10-hydroxy-cis-12-octadecaenoic acid and 10-hydroxy-trans-12-octadecaenoic acid had accumulated. The isolated 10-hydroxy-cis-12-octadecaenoic acid was transformed into CLA during incubation with washed cells of L. acidophilus, suggesting that this hydroxy fatty acid is one of the intermediates of CLA production from linoleic acid. The washed cells of L. acidophilus producing high levels of CLA were obtained by cultivation in a medium containing linoleic acid, indicating that the enzyme system for CLA production is induced by linoleic acid. After 4 days of reaction with these washed cells, more than 95% of the added linoleic acid (5 mg/ml) was transformed into CLA, and the CLA content in total fatty acids recovered exceeded 80% (wt/wt). Almost all of the CLA produced was in the cells or was associated with the cells as free fatty acid.
20
Munday, John S., Keith G. Thompson, and Kerry A. C. James. "Dietary conjugated linoleic acids promote fatty streak formation in the C57BL/6 mouse atherosclerosis model." British Journal of Nutrition 81, no. 3 (March 1999): 251–55. http://dx.doi.org/10.1017/s0007114599000458.
Анотація:
Conjugated linoleic acids (CLA) are positional isomers of linoleic acid which have been suggested by some to possess antiatherosclerotic properties. To test this hypothesis, three groups of twenty C57BL/6 mice were fed on atherogenic diets containing: 5 g CLA/kg, 2·5 g CLA + 2·5 g linoleic acid/kg or 5 g linoleic acid/kg. All diets were fed for 15 weeks and contained (g/kg): triacylglycerol 145, free fatty acids 5, cholesterol 10 and cholic acid 5. At the completion of the experimental period, when data from both groups fed on CLA were combined, dietary CLA did not produce significant differences in body weight, serum total cholesterol concentration or serum HDL-cholesterol concentration. However, mice receiving CLA developed a significantly higher serum HDL-cholesterol: total cholesterol ratio and a significantly lower serum triacylglycerol concentration than controls. Despite causing a serum lipoprotein profile considered to be less atherogenic, the addition of CLA to the atherogenic diet increased the development of aortic fatty streaks. Considering the increased atherogenesis associated with dietary CLA in the present study, and the failure to demonstrate a significant beneficial effect of CLA in other animal studies, there is currently no conclusive evidence to support the hypothesis that CLA protect against atherogenesis.
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Cruz-Hernandez, Cristina, Zeyuan Deng, Jianqiang Zhou, Arthur R. Hill, Martin P. Yurawecz, Pierluigi Delmonte, Magdi M. Mossoba, Michael E. R. Dugan, and John K. G. Kramer. "Methods for Analysis of Conjugated Linoleic Acids and trans-18:1 Isomers in Dairy Fats by Using a Combination of Gas Chromatography, Silver-Ion Thin-Layer Chromatography/Gas Chromatography, and Silver-Ion Liquid Chromatography." Journal of AOAC INTERNATIONAL 87, no. 2 (March 1, 2004): 545–62. http://dx.doi.org/10.1093/jaoac/87.2.545.
Анотація:
Abstract Conjugated linoleic acids (CLA) are octadecadienoic acids (18:2) that have a conjugated double-bond system. Interest in these compounds has expanded since CLA were found to be associated with a number of physiological and pathological responses such as cancer, metastases, atherosclerosis, diabetes, immunity, and body fat/protein composition. The main sources of these conjugated fatty acids are dairy fats. Rumen bacteria convert polyunsaturated fatty acids, especially linoleic and linolenic acids, to CLA and numerous trans- containing mono- and diunsaturated fatty acids. It has been established that an additional route of CLA synthesis in ruminants and monogastric animals, including humans, occurs via Δ9 desaturation of the trans-18:1 isomers. To date, a total of 6 positional CLA isomers have been found in dairy fats, each occurring in 4 geometric forms (cis,trans; trans,cis; cis,cis; and trans,trans) for a total of 24. All of these CLA isomers can be resolved only by a combination of gas chromatography (GC), using 100 m highly polar capillary columns, and silver-ion liquid chromatography, using 3 of these 25 cm columns in series. Complete analysis of all the trans-18:1 isomers requires prior isolation of trans monoenes by silver-ion thin-layer chromatography (TLC), followed by GC analysis using the same 100 m capillary columns operated at low temperatures starting from 120°C. These analytical techniques are required to assess the purity of commercial CLA preparations, because their purity will affect the interpretation of any physiological and/or biochemical response obtained. Prior assessment of CLA preparations by TLC is also recommended to determine the presence of any other impurities. The availability of pure CLA isomers will permit the evaluation and analysis of individual CLA isomers for their nutritional and biological activity in model systems, animals, and humans. These techniques are also essential to evaluate dairy fats for their content of specific CLA isomers and to help design experimental diets to increase the level of the desired CLA isomers in dairy fats. These improved techniques are further required to evaluate the CLA profile in monogastric animals fed commercial CLA preparations for CLA enrichment of animal products. This is particularly important because absorption and metabolism will alter the ingested-CLA profile in the animal fed.
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Luna, Pilar, Javier Fontecha, Manuela Juárez, and Miguel Angel de la Fuente. "Conjugated linoleic acid in ewe milk fat." Journal of Dairy Research 72, no. 4 (May 23, 2005): 415–24. http://dx.doi.org/10.1017/s0022029905001032.
Анотація:
Ewe milk fat from five different herds was studied to determine the content of conjugated linoleic acid (CLA) isomers. Research was carried out by combining gas chromatography-mass spectrometry (GC-MS) of fatty acid methyl esters (FAME) and 4,4-dimethyloxazolyne derivatives (DMOX) with silver ion-high performance liquid chromatography (Ag+-HPLC). Reconstructed mass spectral profiles of CLA characteristic ions from DMOX were used to identify positional isomers and Ag+-HPLC to quantify them. Total CLA content varied from 0·57 to 0·97 g/100 g of total fatty acids. FAME and DMOX were separated into a complex mixture of minor isomers and major rumenic acid (9-cis 11-trans C18:2) by GC-MS using a 100-m polar capillary column. Rumenic acid would represent more than 75% of total CLA. 11-trans 13-trans, 11–13 cis/trans plus trans/cis and 7–9 cis/trans plus trans/cis were the main CLA isomers after rumenic acid. Minor amounts of 8–10 and 10–12 C18:2 isomers were also found. Although most of the isomers were present in each herd's milk, differences in content were observed for some CLA species.
23
Baumgard, Lance H., Benjamin A. Corl, Debra A. Dwyer, A. Saebø, and Dale E. Bauman. "Identification of the conjugated linoleic acid isomer that inhibits milk fat synthesis." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 278, no. 1 (January 1, 2000): R179—R184. http://dx.doi.org/10.1152/ajpregu.2000.278.1.r179.
Анотація:
Conjugated linoleic acids (CLA) are octadecadienoic fatty acids that have profound effects on lipid metabolism. Our previous work showed that CLA (mixture of isomers) markedly reduced milk fat synthesis. In this study, our objective was to evaluate the effects of specific CLA isomers. Multiparous Holstein cows were used in a 3 × 3 Latin square design, and treatments were 4-day abomasal infusions of 1) skim milk (control), 2) 9,11 CLA supplement, and 3) 10,12 CLA supplement. CLA supplements provided 10 g/day of the specific CLA isomer ( cis-9, trans-11 or trans-10, cis-12). Treatments had no effect on intake, milk yield, or milk protein yield. Only the 10,12 CLA supplement affected milk fat, causing a 42 and 44% reduction in milk fat percentage and yield, respectively. Milk fat composition revealed that de novo synthesized fatty acids were extensively reduced. Increases in ratios of C14:0 to C14:1 and C18:0to C18:1 indicated the 10,12 CLA supplement also altered Δ9-desaturase. Treatments had minimal effects on plasma concentrations of glucose, nonesterified fatty acids, insulin, or insulin-like growth factor-I. Overall, results demonstrate that trans-10, cis-12 CLA is the isomer responsible for inhibition of milk fat synthesis.
24
Oikawa, Daichi, Tomonori Nakanishi, Yoshi-nori Nakamura, Takaya Yamamoto, Atsuko Yamaguchi, Nobuya Shiba, Hisao Iwamoto, Tetsuya Tachibana, and Mitsuhiro Furuse. "Modification of skin composition by conjugated linoleic acid alone or with combination of other fatty acids in mice." British Journal of Nutrition 94, no. 2 (August 2005): 275–81. http://dx.doi.org/10.1079/bjn20051488.
Анотація:
The effects of conjugated linoleic acid (CLA), γ-linolenic acid (GLA), linoleic acid (LA), and their combinations, on skin composition in mice were investigated. Mice (8 weeks old) were orally administered with either LA, GLA, CLA, LA + GLA, LA + CLA, or CLA + GLA for 4 weeks. Then, the skin was analysed for triacylglycerol content, fatty acid composition and collagen content. Additionally, thicknesses of the dermis layer and subcutaneous tissue layer, and the size and number of adipocytes were measured histologically. The skin fatty acid composition was modified depending upon the fatty acid composition of supplemented oils. In each oil-alone group, skin triacylglycerol content was the highest in LA, followed by GLA and CLA treatments. Combinations with CLA had a similar triacylglycerol content compared with the CLA-alone group. No significant changes in collagen content were observed among any treatments. The effects on subcutaneous thickness were similar to the results obtained in the triacylglycerol contents, where groups supplemented with CLA alone or other fatty acids had significantly thinner subcutaneous tissue compared with the LA-alone group. However, no significant difference was detected in the thickness of the dermis layers. The number of adipocytes was highest in the LA + GLA group and tended to be reduced by CLA with or without the other fatty acids. These results suggest that CLA alone or in combination with other fatty acids strongly modifies skin composition in mice.
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Czauderna, M., J. Kowalczyk, M. Marounek, J. P. Michalski, and A. J. Rozbicka-Wieczorek. " A new internal standard for HPLC assay of conjugated linoleic acid in animal tissues and milk." Czech Journal of Animal Science 56, No. 1 (January 20, 2011): 23–29. http://dx.doi.org/10.17221/336/2009-cjas.
Анотація:
A new method for the quantification of underivatized conjugated linoleic acid (CLA) isomers and CLA-metabolites by silver ion liquid chromatography (Ag<sup>+</sup>-HPLC) with photodiode array detection (DAD) is described. Conjugated fatty acids (CFA) and sorbic acid as the internal standard (IS) were separated on two 5 μm Chrompac ChromSpher Lipids columns (250 × 4.6 mm). Biological samples were hydrolyzed with 1M KOH in methanol and 2M KOH in water at room temperature for 12 h. Hydrolyzates were acidified and the free fatty acids were extracted with dichloromethane. The organic solvent was removed and then the residue was re-dissolved in hexane and centrifuged. The supernatant was injected onto the columns. The mobile phase of 1.6% acetic acid and 0.0125% acetonitrile in hexane was chosen as the optimum mobile phase for fractionation of IS, CLA isomers and CLA-metabolites in all assayed biological samples. The use of two silver ion-exchange columns with direct UV detection (Ag<sup>+</sup>-HPLC-DAD) offers satisfactory precision of the IS quantification and low limits of detection of IS and CLA isomers (0.60 and 0.21–0.35 ng, respectively). The presented simple Ag<sup>+</sup>-HPLC-DAD method with sorbic acid as the IS can be used for direct determination of underivatized CLA isomers in specimens of animal origin.
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Mitchell, Patricia L., and Roger S. McLeod. "Conjugated linoleic acid and atherosclerosis: studies in animal models." Biochemistry and Cell Biology 86, no. 4 (August 2008): 293–301. http://dx.doi.org/10.1139/o08-070.
Анотація:
Conjugated linoleic acids (CLA) are isomeric forms of linoleic acid (LA) containing two conjugated sites of unsaturation. The most abundant dietary form of CLA is the cis-9,trans-11 (c-9,t-11) isomer that is found in the fatty tissues and milk of ruminant animals. CLA can also be acquired by ingestion of supplements, which are usually equimolar mixtures of the c-9,t-11 and t-10,c-12 CLA. For more than a decade, the potential for CLA to modify atherosclerosis in animal models has been examined. However, to date, the studies have failed to reach consensus on whether CLA can be effective in reducing the incidence or severity of atherosclerotic lesions, or whether or not plasma lipid and lipoprotein levels can be improved with CLA supplementation. This review will examine the evidence for and against a role for CLA in atherosclerosis, with a focus on the rabbit, the hamster, and the apoE-deficient mouse.
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Ringseis, Robert, and Klaus Eder. "Influence of conjugated linoleic acids on functional properties of vascular cells." British Journal of Nutrition 102, no. 8 (July 22, 2009): 1099–116. http://dx.doi.org/10.1017/s0007114509990304.
Анотація:
Conjugated linoleic acids (CLA) are biologically highly active lipid compounds that inhibit the development of atherosclerotic plaques in experimental animals. The underlying mechanisms of action, however, are only poorly understood. Since cell-culture experiments are appropriate to provide a detailed view into the mechanisms of action of a compound, the present review summarises results from in vitro studies dealing with the effects of CLA isomers and CLA mixtures on functional properties of cells of the vascular wall, such as endothelial cells, smooth muscle cells and monocyte-derived macrophages, which are amongst the major cells contributing to atherosclerotic lesion development. Based on these studies, it can be concluded that CLA exert several beneficial actions in cells of the vascular wall through the activation of nuclear PPAR. These actions of CLA, which may, at least partially, explain the inhibition of atherogenesis by dietary CLA, include modulation of vasoactive mediator release from endothelial cells, inhibition of inflammatory and fibrotic processes in activated smooth muscle cells, abrogation of inflammatory responses in activated macrophages, and reduction of cholesterol accumulation in macrophage-derived foam cells.
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Schneider, Anne-Catherine, Eric Mignolet, Yves-Jacques Schneider, and Yvan Larondelle. "Uptake of conjugated linolenic acids and conversion to cis-9, trans-11-or trans-9, trans-11-conjugated linoleic acids in Caco-2 cells." British Journal of Nutrition 109, no. 1 (April 4, 2012): 57–64. http://dx.doi.org/10.1017/s0007114512000608.
Анотація:
Dietary oils containing large amounts of conjugated linolenic acids (CLnA) may be regarded as a source of conjugated linoleic acids (CLA), which have been suspected to bear health-promoting properties. Indeed, CLnA can be converted into CLA in mammals. The objective of the present study was to investigate the uptake of CLnA and their metabolism into CLA in Caco-2 cells, as a validated in vitro model of the intestinal barrier. Caco-2 cells were incubated for 24 h in the presence of either α-eleostearic, β-eleostearic, catalpic or punicic acid. We first observed that Caco-2 cells take these CLnA up at different rates and then convert them but with varying efficiency depending on the structure of the Δ13 double bond. Finally, the distribution of CLnA between neutral lipids (NL) and phospholipids appeared to be linked to their number of trans double bonds: the higher the number, the higher the accumulation in the NL fraction.
29
Kyselka, J., L. Thomes, S. Remišová, M. Dragoun, M. Berčíková, and V. Filip. "Preparation of conjugated linoleic acid enriched derivatives by conventional and biphasic isomerisation." Czech Journal of Food Sciences 34, No. 6 (December 21, 2016): 511–21. http://dx.doi.org/10.17221/362/2016-cjfs.
Анотація:
The preparation of conjugated linoleic acid (CLA)-enriched free fatty acids by industrial processes compared with our biphasic isomerisation experiments in a special designed reactor enabling the preparation of CLA esters was evaluated. Our experiments further revealed the main disadvantage of semi-synthetic alkali isomerisation to be the formation of conjugated E,E-octadecadienoic acid isomers (2.92–3.44%) and the bioavailability of free fatty acid products. Urea fractionation technology improved the quality of the reaction mixture, but at the same time the yield of rumenic acid was decreased on purification. Therefore, we decided to apply complexes of noble metals in order to isomerise linoleic acid ester derivatives. The known Wilkinson’s hydrogenation catalyst, RhCl (PPh<sub>3</sub>)<sub>3</sub>, was found to be the most effective. We investigated the preparation of bioavailable CLA-enriched triacylglycerols. Special attention was paid to recycling of Wilkinson’s catalyst.
30
Wasilewski, Przemysław, Jerzy Nowachowicz, Grażyna Michalska, Tomasz Bucek, Brendan Lynch, and Anne Mullen. "Backfat Fatty Acid Profile of Crossbred Pigs Fed a Diet Supplemented with Conjugated Linoleic acid or Sunflower Oil." Annals of Animal Science 12, no. 3 (May 1, 2012): 433–43. http://dx.doi.org/10.2478/v10220-012-0037-z.
Анотація:
Backfat Fatty Acid Profile of Crossbred Pigs Fed a Diet Supplemented with Conjugated Linoleic acid or Sunflower OilThe aim of the study was to investigate the impact of feeding pigs with different levels of conjugated linoleic acid (CLA) or sunflower oil (SFO) on the backfat fatty acid profile. The subjects of research were 60 crossbred gilts divided into 6 groups, which were fed different levels of conjugated linoleic acid or sunflower oil (0.5, 1.0 and 2.0%, respectively). All fatteners were kept and fed under standardized conditions. Animals were slaughtered at 95 kg of body weight. Fatty acid profile was determined in samples of backfat from each animal using gas chromatography. The significance of differences between groups was verified by Duncan's test. In the present study, a beneficial effect of adding CLA was that it reduced saturated fatty acids and increased unsaturated fatty acids in the adipose tissue (backfat) of pigs as compared to fatteners receiving SFO. The amount of monounsaturated fatty acids in the backfat decreased with increasing amounts of CLA or SFO. Modifying the fatty acid profile of pig backfat through addition of CLA or SFO would be beneficial to the health of consumers because relatively large amounts of fat pork, including backfat, are added to the sausages.
31
Szymczyk, Beata, and Paweł M. Pisulewski. "Effects of dietary conjugated linoleic acid on fatty acid composition and cholesterol content of hen egg yolks." British Journal of Nutrition 90, no. 1 (July 2003): 93–99. http://dx.doi.org/10.1079/bjn2003873.
Анотація:
The main objectives of the present study were to determine the effect of dietary conjugated linoleic acid (CLA) isomers on the fatty acid composition and cholesterol content of egg-yolk lipids. Forty-five 25-week-old laying hens were randomly distributed into five groups of nine hens each and maintained in individual laying cages, throughout 12 weeks of the experiment. They were assigned to the five treatments that consisted of commercial layer diets containing 0, 5, 10, 15 or 20g pure CLA/kg. Feed intake of hens varied little and insignificantly. Egg mass was uniformly lower (P<0·05) in the hens fed the CLA-enriched diets. Feed conversion efficiency, when expressed per kg eggs, was impaired (P<0·05), although without obvious relation to the dietary CLA concentration. Feeding the CLA-enriched diets resulted in gradually increasing deposition of CLA isomers (P<0·01) in egg-yolk lipids. Saturated fatty acids were increased (P<0·01) and monounsaturated fatty acids decreased (P<0·01). Polyunsaturated fatty acids (PUFA), when expressed as non-CLA PUFA, were also significantly decreased (P<0·01). The most striking effects (P<0·01) were observed for palmitic (16 : 0) and stearic (18 : 0) acids, which increased from 23·6 to 34% and from 7·8 to 18%, respectively. On the other hand, oleic acid (18 : 1n-9) decreased from 45·8 to 24·3%. Among non-CLA PUFA, linoleic (18 : 2n-6) and α-linolenic (18 : 3n-3) acids were strongly (P<0·01) decreased, from 14·2 to 7·7% and from 1·3 to 0·3%, respectively. The same was true for arachidonic (20:4n-6) and docosahexaenoic (22 : 6n-3) acids. The cholesterol content of egg yolks, when expressed in mg/g yolk, was not affected by the dietary CLA concentrations. In conclusion, unless the adverse effects of CLA feeding to laying hens on the fatty acid profile of egg yolks are eliminated, the CLA-enriched eggs cannot be considered functional food products.
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Enser, M., A. M. Wachira, L. A. Sinclair, R. G. Wilkinson, K. G. Hallett, and J. D. Wood. "Conjugated linoleic acid and trans C18:1 in muscle and adipose tissue of lambs fed supplements containing n-3 polyunsaturated fatty acids." Proceedings of the British Society of Animal Science 2002 (2002): 182. http://dx.doi.org/10.1017/s1752756200008383.
Анотація:
Conjugated linoleic acids (CLA) occur in the milk and tissues of ruminants. Although cis-9, trans-11 CLA is an intermediate in the biohydrogenation of linoleic acid in the rumen, duodenal flows of CLA are very low (Scollan et al, 2001) and most CLA appears to be synthesised in tissues from trans-11 C18:1 (vaccenic acid) (Griinari et al, 2000). Trans C18:1 isomers are also produced in the rumen and their amounts are increased when the levels of dietary unsaturated fatty acids are raised. We have investigated the relationship of tissue levels of CLA and trans C18:1 in three breeds of lambs fed supplements of linseed or fish oil to increase trans C18:1.
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Paszczyk, Beata, and Joanna Łuczyńska. "Fatty acids profile, conjugated linoleic acid contents and fat quality in selected dairy products available on the Polish market." Czech Journal of Food Sciences 38, No. 2 (April 30, 2020): 109–14. http://dx.doi.org/10.17221/341/2019-cjfs.
Анотація:
The fatty acid composition, cis-9,trans-11 C18:2 (CLA) content and lipid quality indices in the fat of some dairy products (pasteurised milk, UHT milk, natural yoghurts, bio-yoghurts, yoghurts with fruit and cereal grains, butters and hard cheeses) available on the Polish market were determined. The conducted study demonstrated that the fat extracted from the analysed dairy products was characterised by various contents of fatty acids and various lipid quality indices. In the fat extracted from all the analysed products, saturated fatty acids (SFA) were dominant. The fat from the yoghurts with the fruit and cereal grains was characterised by the highest content of PUFA (polyunsaturated fatty acids), the highest hypocholesterolaemic/hypercholesterolaemic ratio (H/H) and the lowest value of the index of atherogenicity (AI) and the index of thrombogenicity (TI). The fat from the natural yoghurts contained the highest value of MUFA (monounsaturated fatty acids). The fat from the bio-yoghurts (7.62 mg g–1) had the highest mean content of CLA. In the other analysed products, the mean content of the CLA was significantly lower (P < 0.05), but the fat from the UHT milks (3.32 mg g–1 fat) had the lowest content. <br /><br />
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Piamphon, Nonthasak, Chalong Wachirapakorn, Metha Wanapat, and Chainarong Nawanukrow. "Effects of fatty acid sources on conjugated linoleic acid (CLA) and other fatty acids in dairy milk." Proceedings of the British Society of Animal Science 2007 (April 2007): 20. http://dx.doi.org/10.1017/s1752756200019232.
Анотація:
Conjugated linoleic acid (CLA) is aniticarcinogenic, antiatherogenic and antidiabetogenic actives. Research has therefore focused on methods of increasing CLA content in milk fat. Amount of CLA in milk fat was highly related to biohydrogenation of unsaturated fatty acid of rumen microbes. (Bauman et al., 1999). Linoleic acid (C18:2) were the precursors of CLA synthesis. The CLA was also synthesized in the mammary gland of lactating ruminants, using oleic acid (C18:1) as a precursor and activity of delta 9-desaturase (Griinari and Bauman, 1999). Linoleic acid is high in soybean oil (SO) (54.4%) and tuna oil (TO) (20.3%) while oleic acid is high in pork oil (PO) (43.5%) and groundnut oil (GO) (40.7%). Therefore, the objective of this experiment was to compare the increasing of CLA and fatty acid composition in milk fat form cows fed dietary oils obtained from either animal or plant sources.
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Lobos-Ortega, I., I. Revilla, M. I. González-Martín, J. M. Hernández-Hierro, A. Vivar-Quintana, and G. González-Pérez. "Conjugated linoleic acid contents in cheeses of different compositions during six months of ripenin." Czech Journal of Food Sciences 30, No. 3 (April 27, 2012): 220–26. http://dx.doi.org/10.17221/415/2010-cjfs.
Анотація:
The study deals with the effects of the origin of milk (cow, ewe, goat, at different proportions), seasonality, and ripening time on the contents of conjugated linoleic acid (CLA) in 224 samples of cheese. The sum of the cis9, trans11 and trans10, cis12 isomers was determined by GC-FID, after the extraction and methylation of the fatty acids of the samples, observing that the mean amount of CLA was 2.22, 2.72, and 3.54 mg/g of cheese, depending on the proportions of cow’s, goat’s, or ewe’s milks, respectively. The contents in cow’s, ewe’s, and goat’s milk, together with the ripening time and seasonality, were seen to have significant effects (P < 0.05) on the concentration of CLA. The Pearson correlation revealed an inverse correlation between the content of CLA and the % of cow’s milk (r = –0.269, P < 0.01) and seasonality (r = –0.290, P < 0.01), and a direct correlation between CLA content and the % of ewe’s milk (r = 0.312, P < 0.01) and the month of ripening (r = 0.188, P < 0.01).
36
Clouet, P., L. Demizieux, J. Gresti, and P. Degrace. "Mitochondrial respiration on rumenic and linoleic acids." Biochemical Society Transactions 29, no. 2 (May 1, 2001): 320–24. http://dx.doi.org/10.1042/bst0290320.
Анотація:
Rumenic acid (cis-9, trans-11-C18:2) represents approx. 80% of conjugated linoleic acid (CLA) in dairy products. CLA has been shown to exert beneficial effects on health, but little work has been devoted to the ability to oxidize CLA isomers and the role of these isomers in the modulation of β-oxidation flux. In the present study, respiration on rumenic acid was compared with that on linoleic acid (cis-9, cis-12-C18:2) with the use of rat liver mitochondria. In state-3, respiration was decreased by half with rumenic acid in comparison with linoleic acid. In the uncoupled state, respiration on CLA remained 30% lower. The lower ability to oxidize CLA was investigated through characterization of the enzymic steps. Rumenic acid was 33% less activated by acyl-CoA synthase than was linoleic acid. However, after such activation, the transfer of both acyl moieties to carnitine by carnitine acyltransferase I (CAT I) was of the same order. Moreover, CAT II activity was comparable with either isomer. After prior incubation with rumenic acid, oxidation of octanoic acid by re-isolated mitochondria was unimpaired, but that of palmitoleic acid was impaired unless linoleic acid was used in the prior incubation. The slower respiration on cis-9, trans-11-C18:2 is suggested to arise from lower carnitine-acylcarnitine translocase activity towards the acylcarnitine form, causing an upstream increase in the corresponding acyl-CoA.
37
Marounek, M., V. Skrivanova, A. Dokoupilova, M. Czauderna, and A. Berladyn. "Meat quality and tissue fatty acid profiles in rabbits fed diets supplemented with conjugated linoleic acid." Veterinární Medicína 52, No. 12 (January 7, 2008): 552–61. http://dx.doi.org/10.17221/1886-vetmed.
Анотація:
In this study the deposition of dietary CLA isomers in loin and hindleg meat, liver and fat, and the influence on performance and fatty acid (FA) profile were investigated in growing rabbits. CLA was supplied as synthetically produced oil at 5 and 10 g/kg diet for the whole fattening period (six weeks) or three weeks before the slaughter. CLA had no or limited effect on feed intake, growth, carcass traits and composition of meat. Treatment with CLA increased the proportion of saturated FA at the expense of monounsaturated FA in meat and liver. Supplementation of the diet with CLA increased (<I>P</I> < 0.05) CLA in lipids of meat from < 1 mg/g FA up to 36 mg/g FA. Adipose and hepatic tissue incorporated the highest (44 mg/g FA) and the lowest (14 mg/g FA) amount of CLA, respectively. The concentration of CLA in tissue lipids increased (<I>P</I> < 0.05) with increasing CLA content in the diet. Duration of CLA feeding had no effect on CLA deposition. Thus, dietary inclusion of CLA at higher concentration (10 g/kg) and feeding CLA-supplemented diet for a shorter period seems to be more suitable for production of CLA-containing rabbit meat. The ratio of the two most abundant isomers of CLA,<I> cis</I>-9, <I>trans</I>-11 and <I>trans</I>-10, <I>cis</I>-12 in tissues differed from that in the CLA-enriched diet. In all tissues the relative proportion of the former isomer was lower than in the diet. The experiment demonstrated that feeding synthetic CLA to rabbits is a means of enriching rabbit meat with CLA, which could provide a healthier product for human consumption.
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Li, Kelei, Andrew J. Sinclair, Feng Zhao, and Duo Li. "Uncommon Fatty Acids and Cardiometabolic Health." Nutrients 10, no. 10 (October 20, 2018): 1559. http://dx.doi.org/10.3390/nu10101559.
Анотація:
Cardiovascular disease (CVD) is a major cause of mortality. The effects of several unsaturated fatty acids on cardiometabolic health, such as eicosapentaenoic acid (EPA) docosahexaenoic acid (DHA), α linolenic acid (ALA), linoleic acid (LA), and oleic acid (OA) have received much attention in past years. In addition, results from recent studies revealed that several other uncommon fatty acids (fatty acids present at a low content or else not contained in usual foods), such as furan fatty acids, n-3 docosapentaenoic acid (DPA), and conjugated fatty acids, also have favorable effects on cardiometabolic health. In the present report, we searched the literature in PubMed, Embase, and the Cochrane Library to review the research progress on anti-CVD effect of these uncommon fatty acids. DPA has a favorable effect on cardiometabolic health in a different way to other long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFAs), such as EPA and DHA. Furan fatty acids and conjugated linolenic acid (CLNA) may be potential bioactive fatty acids beneficial for cardiometabolic health, but evidence from intervention studies in humans is still limited, and well-designed clinical trials are required. The favorable effects of conjugated linoleic acid (CLA) on cardiometabolic health observed in animal or in vitro cannot be replicated in humans. However, most intervention studies in humans concerning CLA have only evaluated its effect on cardiometabolic risk factors but not its direct effect on risk of CVD, and randomized controlled trials (RCTs) will be required to clarify this point. However, several difficulties and limitations exist for conducting RCTs to evaluate the effect of these fatty acids on cardiometabolic health, especially the high costs for purifying the fatty acids from natural sources. This review provides a basis for better nutritional prevention and therapy of CVD.
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Kankaanpää, P., B. Yang, H. Kallio, E. Isolauri, and S. Salminen. "Effects of Polyunsaturated Fatty Acids in Growth Medium on Lipid Composition and on Physicochemical Surface Properties of Lactobacilli." Applied and Environmental Microbiology 70, no. 1 (January 2004): 129–36. http://dx.doi.org/10.1128/aem.70.1.129-136.2004.
Анотація:
ABSTRACT Most probiotic lactobacilli adhere to intestinal surfaces, a phenomenon influenced by free polyunsaturated fatty acids (PUFA). The present study investigated whether free linoleic acid, γ-linolenic acid, arachidonic acid, α-linolenic acid, or docosahexaenoic acid in the growth medium alters the fatty acid composition of lactobacilli and their physical characteristics. The most abundant bacterial fatty acids identified were oleic, vaccenic, and dihydrosterculic acids. PUFA, especially conjugated linoleic acid (CLA) isomers and γ-linolenic, eicosapentaenoic, docosahexaenoic, and α-linolenic acids, also were identified in lactobacilli. When lactobacilli were cultured in MRS broth supplemented with various free PUFA, the incorporation of a given PUFA into bacterial fatty acids was clearly observed. Moreover, PUFA supplementation also resulted in PUFA-dependent changes in the proportions of other fatty acids; major interconversions were seen in octadecanoic acids (18:1), their methylenated derivatives (19:cyc), and CLA. Intermittent changes in eicosapentaenoic acid proportions also were noted. These results were paralleled by minor changes in the hydrophilic or hydrophobic characteristics of lactobacilli, suggesting that PUFA interfere with microbial adhesion to intestinal surfaces through other mechanisms. In conclusion, we have demonstrated that free PUFA in the growth medium induce changes in bacterial fatty acids in relation to the regulation of the degree of fatty acid unsaturation, cyclization, and proportions of CLA and PUFA containing 20 to 22 carbons. The potential role of lactobacilli as regulators of PUFA absorption may represent another means by which probiotics could redirect the delicate balance of inflammatory mediators derived from PUFA within the inflamed intestine.
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Chikunya, S., L. A. Sinclair, and R. G. Wilkinson. "Influence of dietary n -3 polyunsaturated fatty acids on milk fat composition and performance of lactating Friesland ewes." Proceedings of the British Society of Animal Science 2002 (2002): 11. http://dx.doi.org/10.1017/s1752756200006670.
Анотація:
The health benefits of n -3 polyunsaturated fatty acids (PUFA) and conjugated linoleic acid (CLA) to humans are now widely recognised. Polyunsaturated fatty acids of the n -3 series such as a-linolenic acid (C18:3n -3), eicosapentaenoic acid (C20:5n -3; EPA) and docosahexaenoic acid (C22:6n -3; DHA) reduce the risk of coronary heart diseases (Department of Health, 1994). CLA has a diverse array of potential beneficial health effects which include anticarcinogenesis, antiatherogenesis, immune system modulation, antidiabetic effects and reduction of body fat accretion (Bessa et al., 2000). However, the consumption of both n -3 PUFA and CLA by humans is currently less than optimal. The current study investigates the extent to which n -3 PUFA and CLA in milk fat of lactating ewes may be enhanced by feeding diets rich in EPA and DHA.
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Lock, A. L., and P. C. Garnsworthy. "The occurrence of conjugated linoleic acid in the milk of dairy cows." Proceedings of the British Society of Animal Science 1999 (1999): 209. http://dx.doi.org/10.1017/s1752756200003641.
Анотація:
Conjugated linoleic acid (CLA) refers to a group of positional and geometric isomers (cis/trans-9-11 or cis/trans-10-12) of linoleic acid (cis-9, cis-12-octadecadienoic acid). CLA is formed in the rumen by the anaerobic bacteria Butyrivibrio fibrivsolvens as an intermediate step in biohydrogenation of unsaturated fatty acids. CLA has recently gained considerable attention due to its anticarcinogenic and antioxidative properties (Belury, 1995). Therefore, it may be desirable to increase the level of CLA in milk as a health benefit in human nutrition. The concentration of CLA in milk fat and milk products has been reported to vary considerably (Lin et al, 1995). However little work has been conducted under UK conditions. The objective of this work was to study changes in CLA content of cows’ milk throughout the year and investigate the influence of various performance measures on CLA content and yield.
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Cardinal, Kátia Maria, Mariana Lemos De Moraes, Rodrigo Borille, Gustavo Dias Lovato, Marcos Speroni Ceron, Lucas De Marques Vilella, and Andréa Machado Leal Ribeiro. "Effects of Dietary Conjugated Linoleic Acid on Broiler Performance and Carcass Characteristics." Journal of Agricultural Science 9, no. 5 (April 12, 2017): 208. http://dx.doi.org/10.5539/jas.v9n5p208.
Анотація:
The effects of three levels of conjugated linoleic acid dietary inclusion on the carcass characteristics and performance of broilers were evaluated. A total of 405 chickens were raised from 1 until 42 days of age, housed in a room with water and food ad libitum. The experimental design was completely randomized, with three treatments (0.0, 0.5 and 1% CLA) and nine replications (pen) to performance analysis, 18 replications (two birds per pen) to carcass composition, and five replications (left legs) to lipid profile. Performance was determined weekly and after 42 days, 18 birds per treatment were slaughtered to quantify breast and leg yield. Protein and fat was quantified in the leg and breast, as well as the detailed lipid profile of the leg. Data were analyzed by ANOVA and means compared by LS means. From 1 to 21 days chickens with 0% supplementation of CLA performed better compared to those receiving 0.5 and 1% CLA (P < 0.05), however, these differences were no longer significant from 21 to 42 days or for the overall study period (P > 0.05). Conjugated linoleic acid inclusion did not influence leg, breast and carcass yield, and leg and breast content of protein and fat. Both levels of CLA changed the leg lipid profile: there was an increased accumulation of CLA in meat, increased levels of saturated fatty acids and reduction of polyunsaturated fatty acids. Conjugated linoleic acid supplementation increased n-6:n-3 ratio. CLA supplementation in broiler feed is effective to produce meat enriched with its isomers and change lipid profile.
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Hegazy, Mona, Naglaa M. Elsayed, Hala M. Ali, Hanan G. Hassan, and Laila Rashed. "Diabetes Mellitus, Nonalcoholic Fatty Liver Disease, and Conjugated Linoleic Acid (Omega 6): What Is the Link?" Journal of Diabetes Research 2019 (April 8, 2019): 1–7. http://dx.doi.org/10.1155/2019/5267025.
Анотація:
Background and Objective. Type 2 DM and obesity are the coming epidemics and their association with NAFLD is well established; essential fatty acids are vital for body health yet the body cannot make them; 2 essential fatty acids are especially important: linoleic (omega-6) and alpha-linoleic (omega-3) acids; they can be considered as “bioactive lipids” and serve as functional foods. Methods. 50 type 2 Egyptian diabetic patients controlled on oral hypoglycemic drugs together with 20 age- and sex-matched healthy participants were enrolled in the study; all were subjected to complete history taking, BMI, fasting plasma glucose, HOMA-IR, ALT, AST, GGT, urea and creatinine, total lipid profile, hepatitis markers including hepatitis B surface antigen and hepatitis C virus antibodies, conjugated linoleic fatty acid “CLA,” and abdominal ultrasound for grading of NAFLD. Results. Our study in Egyptian diabetics with NAFLD revealed a low level of serum CLA compared to healthy control; such deficiency was more marked with advanced grades of NAFLD; lowest levels were observed in those with severe steatosis (NASH) with definite association between CLA and obesity. Conclusion. Insulin resistance is the main link between NAFLD, diabetes, and obesity. Conjugated linoleic acid (CLA) has a role in fat deposition in the liver and in development and improvement of insulin resistance. Fatty food had a documented role in the pathogenesis of obesity and diabetes but it can also be the cure.
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Dorel, A., N. D. Scollan, M. R. F. Lee, D. R. Yáñez Ruiz, and C. J. Newbold. "Biohydrogenation of linoleic acid and production of conjugated linoleic acids by fractions prepared from bovine rumen fluid." Proceedings of the British Society of Animal Science 2005 (2005): 202. http://dx.doi.org/10.1017/s1752756200011133.
Анотація:
Dietary conjugated linoleic acids (CLA) offer significant health benefits for man, and ruminant products are the major dietary sources (Bauman et al., 2001). The synthesis of CLA in the ruminant animal occurs either directly in the rumen or in the tissue from trans -vaccenic acid (TVA), formed primarily as intermediate products of ruminal biohydrogenation of linoleic acid (C18:2) to stearic acid (C18:0). Within the rumen, the pattern of biohydrogenation and the products formed appear to differ between the particle rich and the liquid fractions of the rumen (Singh and Hawke, 1979), with biohydrogenation occurring primarily on small particles. The aim of this study was to investigate whether the pattern of CLA and TVA formation differs in these fractions.
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de Deckere, Emile A. M., Johan M. M. van Amelsvoort, Gerald P. McNeill, and Penny Jones. "Effects of conjugated linoleic acid (CLA) isomers on lipid levels and peroxisome proliferation in the hamster." British Journal of Nutrition 82, no. 4 (October 1999): 309–17. http://dx.doi.org/10.1017/s0007114599001518.
Анотація:
Effects of the conjugated linoleic acid (CLA) isomers cis-9, trans-11 (c9, t11 CLA) and trans-10, cis-12 (t10, c12 CLA) on lipid metabolism and markers of peroxisome proliferation were investigated in hamsters fed on purified diets containing 30 % energy as fat and 0·1 g cholesterol/kg for 8 weeks. Four groups (n 32 each) received diets without CLA (control), with a mixture of equal amounts of c9, t11 and t10, c12 CLA (CLA mix), with c9, t11 CLA, and with t10, c12 CLA. The total amount of CLA isomers was 1·5 % energy or 6·6 g/kg diet. CLA was incorporated into glycerides and exchanged for linoleic acid in the diet. Compared with the control, the CLA mix and t10, c12 CLA decreased fasting values of LDL- (21 and 18 % respectively) and HDL-cholesterol (8 and 11 %), increased VLDL-triacylglycerol (80 and 61 %), and decreased epididymal fat pad weights (9 and 16 %), whereas c9, t11 CLA had no significant effects. All CLA preparations increased liver weight, but not liver lipids. However, the increase in liver weight was much less in the c9, t11 CLA group (8 %) than in the other two groups (25 %) and might have been caused by the small amount of t10, c12 CLA present in the c9, t11 CLA preparation. Liver histology revealed that increased weight was due to hypertrophy. Markers of peroxisome proliferation, such as cyanide-insensitive palmitoyl CoA oxidase (EC 1.3.3.6) and carnitine acetyl transferase (EC 2.3.1.7) activities, were not increased by CLA. Both c9, t11 CLA and t10, c12 CLA were incorporated into phospholipids and triacylglycerols, but t10, c12 CLA only about half as much as c9, t11 CLA. In addition, linoleic acid and linolenic acid concentrations were lower in lipids of the t10, c12 CLA group compared with the c9, t11 CLA group. These data suggest that t10, c12 CLA stimulated the oxidation of all C18 polyunsaturated fatty acids. The results indicate that the t10, c12 CLA isomer, and not the so-called natural CLA isomer (c9, t11), is the active isomer affecting lipid levels in hamsters.
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Bauer, P., P. Horlacher, and P. Claus. "Direct Isomerization of Linoleic Acid to Conjugated Linoleic Acids (CLA) using Gold Catalysts." Chemical Engineering & Technology 32, no. 12 (December 2009): 2005–10. http://dx.doi.org/10.1002/ceat.200900384.
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Tappia, Paramjit S., Rabban Mangat, Cindy Gabriel, Melissa R. Dent, Nina Aroutiounova, and Hope Weiler. "Gender differences in the cardiac response to dietary conjugated linoleic acid isomers." Canadian Journal of Physiology and Pharmacology 84, no. 2 (February 2006): 257–64. http://dx.doi.org/10.1139/y05-149.
Анотація:
The present study was undertaken to assess the heart function, by the in vivo catheterization technique, of healthy male and female Sprague–Dawley rats fed different conjugated linoleic acid (CLA) isomers, (cis-9, trans-11 (c9,t11) and trans-10, cis-12 (t10,c12)) individually and in combination (50:50 mix as triglyceride or fatty acids) from 4 to 20 weeks of age. Whereas the triglyceride form of the CLA isomer mix lowered the heart rate, the rate of contraction (+dP/dt) and rate of relaxation (–dP/dt), systolic and diastolic pressures, mean arterial pressure, and the left ventricular systolic pressure were higher in male rats as compared with all the other dietary groups. In contrast, there were no significant effects in the cardiac function of the female rats in response to the CLA isomer mix in triglyceride form. Whereas the heart rate, +dP/dt, and left ventricular systolic pressure were lower in male rats fed the t10,c12 CLA isomer alone, the heart rate of the female rats was higher, but the systolic pressure, +dP/dt, and mean arterial pressure were lower compared with the control group. Also, the left ventricular end-diastolic pressure was specifically higher in the female rats in response to free fatty acids-containing CLA mix. Furthermore, an additive effect of the free fatty acids-containing CLA mix was seen in the +dP/dt and –dP/dt of female rats compared with the control group. These results indicate that CLA isomers exert differential effects on heart function and suggest the need for a complete evaluation of the benefits, interactions, and potential side effects of each isomer.
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Borosné Győri, Anikó, Istvánné Hermán, János Csapó, and János Gundel. "The possibility of increasing at the conjugated linoleic acid content in pork." Acta Agraria Debreceniensis, no. 31 (November 24, 2008): 27–32. http://dx.doi.org/10.34101/actaagrar/31/3001.
Анотація:
The composition of fatty acids in food products is a significant factor in human health. Feeding can significantly influence the composition of fatty acids in the animal fat. We analysed the effect of feeding high CLA-content (conjugated linoleic acid) feed on the composition of fatty acids in pork. The animals were grouped according to the following: Group 1) feeding experimental, ghee-mixed feed for 76 days, Group 2) feeding the same feed, but only for 33 days, Group 3) feeding sunflower-oil-mixed feed for 76 days. Ghee contains CLA in high amount. The aim of our experiment is to analyse how the high CLA content influences the fatty acid content of pork. In the end of the fattening experiment the animals were slaughtered, then samples were taken from the loin, ham, abdomen and backfat from 10 animals from each group and analysed the fatty acid content. We found significant differences between the average fatty acid content of the samples. As an effect of feeding ghee-enriched feed, the CLA content significantly increased, compared to the control group. However, the linoleic acid and the arachidonic acid content were lower, and the proportion of fatty acids was also lower when feeding control feed.
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Delmonte, Pierluigi, Martin P. Yurawecz, Magdi M. Mossoba, Cristina Cruz-Hernandez, and John K. G. Kramer. "Improved Identification of Conjugated Linoleic Acid Isomers Using Silver-Ion HPLC Separations." Journal of AOAC INTERNATIONAL 87, no. 2 (March 1, 2004): 563–68. http://dx.doi.org/10.1093/jaoac/87.2.563.
Анотація:
Abstract Silver-ion high-performance liquid chromatography (Ag+-HPLC) has been shown to be effective in the resolution of most of the isomers of conjugated octadecadienoic acids (18:2), also known as conjugated linoleic acid (CLA). The CLA isomers identified in natural fats from ruminants are a mixture of numerous positional and geometric isomers from 7,9- to 12,14–18:2. Ag+-HPLC separates both geometric (trans,trans < cis/trans < cis,cis) and positional CLA isomers using the mobile phase hexane/acetonitrile (99.9:0.1). The elution volumes for the CLA isomers were not only affected by the concentration of acetonitrile (in the prepared mobile phase) but also with successive runs during the day using a prepared mobile phase batch, due to the partial solubility of acetonitrile in hexane. However, this drift does not affect the relative resolution of the CLA isomers. The addition of diethyl ether to the mobile phase partly stabilizes the solvent mixture. In order to facilitate the interpretation of Ag-+HPLC chromatograms, the relative retention volumes (RRV) were calculated for each CLA isomer. Toluene was added to all the test portions and served as an estimator of dead volume, whereas the elution of the ubiquitous 9c,11t-CLA isomer was chosen as unity (1.00). Expressing the elution of all the CLA isomers as their RRV greatly helped to standardize each CLA isomer, resulting in relatively small coefficients of variation (% CV) for the trans,trans (<1.5%) and cis/trans (<0.5%) CLA isomers. The identification of the CLA isomers was further facilitated by synthesis of authentic CLA isomers. All the geometric CLA fatty acid methyl esters (FAME) from positions 6,8- to 13,15-CLA were commercially available or synthesized by a combination of partial hydrazine reduction of known polyunsaturated fatty acids followed by alkali isomerization, isolation of products, and further iodine-catalyzed geometric isomerization. Based on expressing the elution volume as RRV and the availability of the synthetic CLA isomers, a unique reversal of the elution order of the c/t CLA isomers was found. It is also proposed that the retention times of CLA isomers by gas chromatography (GC) should be expressed as their relative retention times (RRT) relative to methyl γ-linoleneate. The availability of CLA reference materials and the application of RRV and RRT to Ag+-HPLC and GC separations, respectively, will greatly improve in the identifications of CLA isomers.
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Stanimirovic, M., B. Petrujkic, N. Delic, N. Djelic, J. Stevanovic, and Z. Stanimirovic. "Dietary conjugated linoleic acid influences the content of stearinic acid in porcine adipose tissu." Veterinární Medicína 57, No. 2 (February 27, 2012): 92–100. http://dx.doi.org/10.17221/5255-vetmed.
Анотація:
The present study was conducted in order to determine the effects of supplementation of a growing-finishing pig diet with 0.5% conjugated linoleic acid (CLA) on production characteristics and slaughter traits. Ninety-seven female Swedish Landrace pigs were used. The control group of animals was fed a regular diet (n = 49), while the experimental group of animals (n = 48) received a diet where part of the soybean oil was substituted with commercially enriched CLA oil (containing at least 56% of CLA isomers, 28% cis-9, trans-11 and 28% trans-10, cis-12). The experiment lasted 44 days; porkers were fed from an initial weight of 66.0 up until a final weight of 103.5 kg. Feed conversion ratio, carcass and ham weight, percentage of lean meat and subcutaneous fat tissue as well as intramuscular fat were recorded. The fatty acid content of ham intramuscular fat tissue was determined by HPLC. No statistically significant influence of CLA was observed, either on carcass and ham weight, or on fat percentage in subcutaneous and intramuscular tissue. Dietary CLA enrichment proved to increase the content of stearinic acid in intramuscular fat tissue, 17.29 ± 13.26 % in experimental and 15.87 ± 33.71 % in control group of pigs (P < 0.01). The obtained production results show no statistically significant changes in main production traits between the two groups of animals. The observed difference in the content of stearinic acid (P < 0.01) implies firmer fat tissue, which has a practical value in pig bacon fattening.