Academic literature on the topic 'Bovine lactoferrin'

Bovine lactoferrin (BLF) and bovine transferrin (BTF) are major-iron transport and regulation proteins found in bovine whey. BLF and BTF must interact with the eukaryotic cell surface to mediate their biological function of iron delivery and cellular functions of inflammatory and immunological modulation. As common components of the eukaryotic cell surface, gangliosides were used for affinity purification of BLF and BTF. Bovine gangliosides were isolated from fresh buttermilk and covalently immobilized onto controlled-pore glass beads (66 μg/g beads). After the matrix was loaded with whey protein (WPI or WPC), lactoferrin was eluted with 1 M NaCl and lll identified by N-terminal protein sequencing. Pretreated whey isolate (1 % wt/vol) showed the highest lactoferrin purity with 40% among protein sources, and whey protein isolate (10% wt/vol) showed the highest recovery with 105%. Bovine transferrin was eluted with sodium phosphate buffers at pH 7 after the immobilized matrix was loaded with a 2% (wt/vol) whey solution. The ganglioside column resulted in a 74.2% recovery of BTF from whey, and the BTF was enriched to 61% purity after Mono-Q chromatography. Bovine transferrin was identified by SDS-PAGE analysis, Western analysis, and isoelectrofocusing. In conclusion, immobilized gangliosides can be used to purify BLF and BTF from bovine whey.

A series of investigations were carried out to assessth e intestinal microbiota of rainbow trout and the potential applications of probiotics and bovine lactoferrin (M). Farm and aquarium reared rainbow trout were examined with specific emphasis on the autochthonous microbial communities. Culture-based, culture-independent and electron microscopical investigations revealed mixed, complex microbial communities in all intestinal regions. DGGE based analysis revealed unique species present either only as allochthonous populations or autochthonous populations. 16S rRNA sequence analysis allowed species level identification of a range of isolates, many of which have not been identified from the rainbow trout digestive tract previously. Two ftirther investigations were carried out to assess the potential of using commercial probiotics and bovine Lf on growth, feed utilisation, health and intestinal colonisation of rainbow trout. Standard commercial diets were supplemented with B. subtills, B. licheniformis and Enterococcus faecium either singularly or synergistically. When comparing the findings of the joint study it can be concluded that the application of probiotics with rainbow trout, and likely other finfish species, is highly complicated. Full intestinal replacement of indigenous microbiota is not likely to be a good idea when using E. faecium; the results indicate that a synergistic relationship with the indigenous microbiota is likely to be involved in providing host benefits. Bacillus probiotics only appeared to be effective at high intestinal levels indicating that a synergistic relationship with the indigenous microbiota may not be as important. T'he joint study also indicates that it is not always possible to reproduce probiotic benefits even when using the same probionts, the same fish species and similar rearing conditions. Thus, the physiological status of the fish and the indigenous microbiota are likely to play an important role in the outcome of probiotic administration. A subsequent trial was conducted to evaluate Pediococcus acidilactic! as a probiotic for rainbow trout. The experiment was conducted to supplement the diet with either vegetative cells or lyophilised powder (as commercially provided). Despite successful intestinal colonisation, irrelevant of supplementation form few significant benefits were observed. SEM of the posterior mucosa revealed a localised colonisation pattern of P. acidilactic! between the mucosal folds similar to the observed indigenous microbiota from the farmed fish. This revelation led to a further trial to investigate the nature of probiotic colonisation through the gastro-intestinal tract using electron microscopy. The study confirmed the high colonisation of P. acidilactici on the epithelium of the anterior intestine and posterior intestine. However, it was not possible to observe such colonisation with Bacillus spp. or E. faeclum; despite culture-based results to the contrary. It is likely that the true mucosal colonisation may sometimes be confused with colonisation of the mucus layer as opposed to actual attachment to the epithelium itself. Therefore, it is crucial to utilise electron microscopy in order to confirm epithelial colonisation. The nature of both the indigenous microbiota and the application of probiotics appears to be more complicated than previously thought and continued research is clearly warranted.

Methods for on-farm extraction of low-concentration (minor) proteins from raw whole bovine milk directly after milking were explored. These minor proteins have high commercial value. Lactoferrin (LF) and lactoperoxidase (LP) were used as model proteins for extraction using cation exchange chromatography. Laboratory fractionations showed that milk could be processed by conventional column chromatography without excessive column backpressures if resin with large particles sizes were used and the temperature was high enough so fat in the milk was malleable; ideally the milk should be near the secretion temperature of 37oC. Processing parameters such as equilibrium and dynamic capacities were determined for SP Sepharose ™ (GE Healthcare Technologies) and Bio Rex 70 (BioRad Laboratories) resins. SP Sepharose Big Beads (SP BB) were found to be more suitable than BR 70, for raw whole milk processing due to the larger size (200 um). Design considerations showed that column chromatography was not the most practical method for on-farm processing of fresh, raw whole milk. Trials with a single-stage stirred tank showed that SP BB resin could extract up to 65% of LF (initial LF concentration of 0.5 mg/mL) with a 10-minute adsorption time. The composite non-linear (CNL) model of Rowe et al. (1999) was used to describe LF uptake by SP BB resin in raw whole milk with initial LF concentrations of 0 to 1.0 mg/mL and resin:milk volume ratios of 0.010, 0.012, 0.017 and 0.024 over 45-minute contact times. The CNL model could be used to predict LF yields if initial feed concentration, milk and resin volumes, and contact times were known. Laboratory extractions showed that processing did not significantly affect bulk milk composition (fat, protein, lactose and total solids), indicating that the milk could be used for conventional processing after the minor proteins had been extracted. Resin cleaning and regeneration studies, using a procedure similar to that recommended by the resin supplier, showed that the Sepharose resin had not degraded and there was no significant decrease in binding capacity after 50 extraction cycles. A Protein Fractionation Robot (PFR) prototype based on a single-stage stirred tank and the operating parameters obtained from the laboratory trials was designed, assembled and coupled to an Automated Milking System (AMS) to process fresh, raw whole milk from individual cows immediately after milking. The LF and LP extracted from the milk from 16 individual cows were 19.7 - 55.2% (35.6 10.2%) and 21.2 - 99.5% (87.1 12.0%) respectively. Generally, higher extraction levels were obtained at higher resin:milk ratios. The amount of LF extracted on-farm agreed within 14.1 9.8% of those predicted by the CNL model, with predicted values generally being higher. The experimental on-farm adsorption values were calculated using data of LF recovered after elution, so differences between actual and predicted values may be due to losses during post-adsorption processing. Economic feasibility studies, based on experimental data from the PFR and realistic wholesale prices for LF and LP ($400 and $150/kg respectively) showed that PFR-based processing is economically viable if the farmer is paid for the LF and LP produced as well as the bulk milk. This system would have a payback period of approximately five years and an internal rate of return of 14.5%. Further case studies determined the sensitivity of the economics to various operating parameters and value/cost assumptions, including producing recombinant human protein from transgenic bovine milk. These studies showed that the higher the value of the processed raw milk, the higher the absorptive capacity of the resin, and the higher the value of the extracted protein, the more favourable the economics. In the extreme case of producing a very high value therapeutic protein (e.g. $20 000), the payback period could be as low as 0.3 years, with an internal rate of return of 818%.