Dissertations / Theses on the topic 'Aquafeeds'

With World Health Organization estimation of population increase to over 9 billion by 2050, malnutrition and food insecurity are predicated to be two of the main challenges facing the world in the future. Fish is a source of protein that can have a significant contribution for solving the global food crisis. Fish for human consumption is provided by both the aquaculture industry and the capture fisheries, however, the flat-lined production of seafood from capture fisheries means aquaculture production should double in number to provide enough protein by 2050. Culturing fish at higher densities is being used as a way to increase the global aquaculture production. Modern aquaculture intensified practices expose the fish to various stressors that can negatively impact their welfare. Good nutrition can improve the health status of aquacultured fish while accumulation of specific nutrient can add value to the fillet. In line with that, the studies described in this dissertation aimed to examine the vital role of fish in human health and evaluate strategies to improve the sustainable aquaculture production of fish using novel aquafeeds. This was completed by conducting a survey of the essential minerals and heavy metals of commercially available catfish, salmon, and tilapia fillets in the United States marketplace and three fish nutritional trials to evaluate the impacts of novel aquafeeds on production and health of fish and the food quality of their respective fillets. Selenium with the established health benefit for human and fish was the trace mineral of interest in this dissertation. This element is the main component of a group of selenium containing proteins called selenoproteins that are antioxidant and maintain oxidative homeostasis of fish and human. Additionally, selenium is an antagonist for many heavy metals such as mercury. The market study revealed that catfish, salmon and tilapia samples available in United States marketplace are good source of selenium, zinc and phosphorous. The concentration of heavy metals in all the samples were lower than safety standards. Nile tilapia (Oreochromis niloticus) and rainbow trout (Oncorhynchus mykiss), which are two economically important aquacultured fish, were used as animal models in the fish nutritional trials. Different forms of selenium supplemented to Nile tilapia diet. The form of Dietary Se form did not have any significant (p>0.05) effect on growth, and plasma and hepatic GPX activity of Nile tilapia. However, organic selenium supplement showed significantly (p<0.05) higher bioavailability and accumulated in the fillets at the significantly higher concentration. In the second fish trial selenoneine, a novel selenium containing compound, was supplemented at various concentrations to rainbow trout diet. Other than growth parameters multiple other health biomarkers (lysozyme, glutathione peroxidase, superoxide dismutase activities) were examined to determine whether selenoneine supplementation had a positive impact on fish health. Selenoneine enriched diet significantly(p<0.05) increased the weight gain, lysozyme and oxidative enzymes activities of rainbow trout. Lastly rainbow trout feed was supplemented with commercially available probiotic (Actisaf), prebiotic (Safmmann), and their mixture (synbiotic). These dietary supplements did not have any significant effect on fish production but led to a significant increase in activity of oxidative enzymes in plasma when compared to control diet. These results suggest that feed supplements used in this dissertation can be used to promote the fish health raised in recirculating aquaculture systems and support an economically and environmentally sustainable aquaculture.
PHD

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Este estudo foi desenvolvido para determinar os coeficientes de digestibilidade aparente (CDA) de matéria seca (MS), energia bruta (EB), proteína bruta (PB), amido, lipídios, fibra bruta (FB), cinzas (CZ) e de aminoácidos (AA) essenciais e não essenciais de farinha de feijão in natura (FI) e feijão extrusada (FE) para juvenis de tilápia do Nilo utilizando dois marcadores de digestibilidade: óxido crômio (Cr2O3) ou cinza insolúvel em ácido (CIA). Foi elaborada uma dieta referência peletizada (DR) contendo 35,19% de PB e 17,78 MJ/ kg de EB. As dietas testes constituíam-se de 70% da DR e 30% de FI ou FE. Grupos de 15 individuos (150,16 ± 20,32 g) foram distribuídos em seis aquários de digestibilidade de 200 L, em um esquema fatorial 2 x 2, onde foram avaliados dois métodos de processamento (FI ou FE) e dois marcadores (Cr2O3 ou CIA), com duas repetições, compondo o “pool” de fezes de cada dieta testada. Os maiores CDA, referentes a interação (processamento x marcador), foram encontrados para MS, EB, PB, CZ e AA essenciais como: arginina (Arg), histidina (His), isoleucina (Ile), leucina (Leu), lisina (Lys), metionina (Met),fenilalanina (Phe), treonina (Thr) e nos AA não essenciais: ácido aspártico (Asp), cisteína (Cys), ácido glutâmico (Glu), glicina (Gly), serina (Ser) e tirosina (Tyr). O CDA de amido e para os AA essencias triptofano (Trp) e valina (Val) foi maior no FE em comparação ao FI, deferenciando dos lipídios que apresentaram melhores resultados para FI. Para FB e o AA não essencial alanina (Ala), por sua vez, não houve influência dos tratamentos dietéticos e marcadores. Independentemente do processamento a Met, His e Arg foram os AA limitantes para dietas contendo farinhas de feijão. Em conclusão, a FE apresentou -se como sendo boa fonte de energia e nutrientes, porém, os teores de Met e Cys devem ser considerados para as necessidades dietéticas de AA contendo enxofre e o marcador CIA não se mostrou sendo confiável para tilápia do Nilo.
The trial aimed to evaluate the apparent strain digestibility coefficients (ADC) of dry matter (DM), gross energy (GE), crude protein (CP), starch, lipids, crude fiber (CF), ashes (AS) and essential and non-essential amino acids (AA) of in natura bean flour (FI) and extruded bean flour (FE) for juvenile Nile tilapia using two digestibility markers: chromium oxide (Cr2O3) or acid insoluble ash (AIA). It was elaborated a pelleted reference diet (RD) containing 35.19% CP and 17.78 MJ / kg GE, the test diets consisted of 70% RD and 30% of FI or FE. Groups of 15 individuals (150.16 ± 20.32 g) were distributed in six digestibility aquariums of 200 L, in a 2 x 2 factorial scheme, two processing methods (FI or FE) and two markers (Cr2O3 or AIA) were evaluated, with two replicates, composing the faeces pool of each diet tested. The highest ADC referring to the interaction (processing x marker) were found for DM, GE, CP, As and essential AA as: arginine (Arg), histidine (His), isoleucine (Ile), leucine (Leu), lysine (Lys), methionine (Met), phenylalanine (Phe), threonine (Thr) and for non-essential AAs: aspartic acid (Asp), cysteine (Cys), glutamic acid (Glu), glycine (Gly), serine (Ser) and tyrosine (Tyr). The CDA of the starch and the essential AA tryptophan (Trp) and valine (Val) was higher in FE compared to FI, different from lipids, which presented better results for FI. For GE and nonessential amino acid alanine (Ala) there was no influence of dietary treatments and markers. Regardless of the processing, Met, His and Arg were the limiting AAs for diets containing bean flours. In conclusion, FE proved to be a good source of energy and nutrients, however, the low levels of Met and Cys should be considered for the dietary requirements of AA containing sulfur. The AIA marker proved to be unreliable for Nile tilapia.

Traditionally, fish meal (FM) and fish oil (FO) have been used extensively in aquafeeds, mainly due to their excellent nutritional properties. However, various reasons dictate the use of sustainable alternatives and the reduction of the dependence on these commodities in fish feeds. Hence, the aim of the present thesis was to investigate the effects of the replacement of FM and FO with two vegetable oils (VO) and an oilseed meal on the growth performance, feed utilization, nutrient and fatty acids (FA) digestibility and tissue FA composition and metabolism in three commercially important European fish species. Specifically, in Experiment I crude palm oil (PO) was used to replace FO in diets for rainbow trout. In Experiments II and III FO was replaced with rapeseed oil (RO) in diets for Atlantic salmon at various dietary protein/lipid levels aiming also at further reductions of FM by using low protein (high lipid) diet formulations. In Experiments II and III the fish were reared at low and high water temperatures, respectively, in order to elucidate, also, the potential effects of temperature. Lastly, the effects of the replacement of FM with full fat soya meal (FFS) in Atlantic cod were investigated in Experiment IV. The results of the present thesis showed no negative effects on growth performance and feed utilization in rainbow trout when FO was replaced with PO. The dietary inclusion of RO improved the growth of Atlantic salmon, possibly, due to changes in the nutrient and FA digestibilities and FA catabolism while, the growth and feed utilization were unaffected by the dietary protein/lipid level. However, the growth of Atlantic cod was affected negatively by the replacement of FM with FFS. The proximate composition of the fish whole body was in most cases unaffected by dietary treatments. The changes in dietary formulations affected the dietary FA compositions and resulted in significant changes in the fish tissue FA compositions. It was clearly shown that the fish tissue total lipid FA composition reflects the FA composition of the diet, although specific FA were selectively utilized or retained in the tissues by the fish. These may have serious implications not only for fish metabolism and growth but also for the quality of the final product, especially in terms of possible reductions of n-3 HUFA.

Aquaponics, the integrated production of fish and hydroponic crops in a recirculating system, is an intensive cultivation method in which metabolic fish wastes fertilize plants. This study compares the effects of two aquafeeds on Red amaranth (Amaranthus tricolor) productivity and on water quality under cultivation of Blue tilapia (Oreochromis aureus), with three aquaponic units (n=3) per treatment over a 60-day trial. The fishmeal-based control feed contains higher crude protein (40%) and phosphorus (1.12%) than the plant-based alternative feed (32% and 0.40%). The alternative feed resulted in a significantly higher amaranth crop yield (p

L'allevamento di orate e spigole è una delle più importanti forme di acquacoltura nel Mar Mediterraneo. Grazie allo sviluppo della grande distribuzione organizzata, il consumo ittico negli ultimi anni è cresciuto molto, anche per la percezione positiva da parte del consumatore riguardo la salubrità di questi prodotti; infatti, le specie studiate risultano avere un buon contenuto proteico e un basso tenore lipidico, apportando però discrete quantità di PUFA n-3. È stato dimostrato che la produzione sia di spigole che di orate può comportare tuttavia un impatto ambientale nelle zone di allevamento ed in particolare eutrofizzazione e inquinamento delle acque; infatti questi pesci sono carnivori e necessitano di mangimi con elevato tenore di proteine animali. La produzione di mangimi per le specie ittiche carnivore prevede l’inclusione di oli e farine proteiche di pesce, e rappresenta quindi l’aspetto maggiormente critico in termini di impatto ambientale. In questo elaborato vengono proposte le microalghe come alimento alternativo ai mangimi convenzionali, analizzando le loro proprietà nutrizionali e di tecniche di riproduzione. Risulta che questi organismi conferiscono buone quantità di proteine, di acidi grassi n-3 PUFA, in particolare di EPA e DHA, e si riproducono agevolmente in vari habitat. Nonostante ciò, il prezzo elevato limita il loro impiego in queste produzioni e sono quindi necessari sviluppi in ambito tecnologico per abbassare i costi.

Dusky kob, Argyrosomus japonicus, is an aquaculture species in South Africa that is in pilot commercial production. While the major nutrient requirements of the species are known, the advantages of incorporating formulated feeds into the diet of the species has yet to be fully explored. Research on formulated feed composition is required to: minimise input costs; improve the organoleptic properties and meat quality; and minimise nutrient loss, which contributes to environmental pollution. This study sought to test the impact of different lipid levels in aquafeeds fed to dusky kob juveniles by determining: (i) growth performance, feeding efficiency, proximate and fatty acid composition; (ii) chemical changes and shelf-life of refrigerated fish fillets; and (iii) metabolic rates and nitrogen excretion of juvenile dusky kob. And more...

This body of research explores the dietary application of a bioactive, solid-state fermentation (SSF) product in contemporary and lupin-containing diets of Nile tilapia (Oreochromis niltoticus) and rainbow trout (Oncorhynchus mykiss). Consequently, the work provides holistic assessment of the influences of SSF products on animal health and performance; depending upon rearing temperature, nutritional physiologies, feed formulations and extrusion conditions; alongside information on the performance of lupins in aquafeeds. The SSF product (at 0.1 % inclusion) improved growth performance of Nile tilapia fed diets containing lupins. Phosphorous retention appeared higher when the SSF product was included in a yellow lupin (Lupinus luteus) diet whilst Mg retention was significantly higher in fish fed narrow-leaf lupin (Lupinus angustifolius). The experimental ingredients did not appear to show any clear effects upon midgut macrostructure. At an ultrastructural level, the fish fed yellow lupin alone, displayed poorest brush border characteristics but those fed yellow lupin and the SSF product showed signs of amelioration since they did not differ significantly from those fed narrow-leaf lupin. Focus was then turned towards a yellow lupin-based diet in rainbow trout, with two inclusion levels of the SSF product. The SSF product significantly improved growth performance and feed efficiency at 0.5 %, with values closer to a fishmeal-based diet than the lupin control. The SSF product increased the digestibility of protein and energy and bioavailability of numerous elements. However, the digestibility and bioavailability of certain nutrients, e.g. fibre and Zn, were only increased with a 0.5 % inclusion. The SSF product influenced vertebral Ca:P ratio but no effect on vertebral morphology was identified. Fish fed yellow lupin kernel meal displayed high Mn concentrations throughout a number of tissues. The intestinal environment was explored in depth, revealing large differences dependent upon SSF product inclusion rate. Fish fed a 0.1 % inclusion exhibited deteriorated brush border characteristics and high diversity of microbes, including increased proportions of key salmonid pathogens. Those fed a 0.5 % inclusion displayed signs of increased surface area at an ultrastructural level, reduced goblet cell numbers and a low microbial diversity; with domination of one particular family, Enterobacteriaceae. Activities of alkaline phosphatase and leucine aminopeptidase within the anterior intestine also appeared to be influenced by SSF product inclusion. Variations in haemato-immunological parameters were also observed between the treatments. In the final experiment, the SSF product was applied, pre-extrusion, to a contemporary rainbow trout formulation, at 0, 0.5, 1.0 and 1.5 %. No significant improvements to performance were identified following SSF product inclusion. However, crude protein digestibility from SSF-supplemented diets was significantly higher than the control and tendencies towards elevated retention of Ca, P, and Mg were apparent. In vitro analysis of free-phosphate release was conducted upon pre- and post-extruded diets, at varying temperatures. This indicated that neither extrusion conditions (105 °C) nor an ambient temperature of 10 °C were sufficient to cease P-liberating capabilities by the SSF product; suggesting that the two conditions combined limited the product’s efficacy in practice. This research evidenced that SSF products can be an effective means of improving the available nutrient profiles of compound diets for both omnivorous, warmwater and carnivorous, temperate finfish. Lupins are a promising alternative protein source but their nutritional value can be substantially improved by SSF product application. Exploration of the effects of SSF products on the intestinal environment revealed that both negative and positive effects on intestinal health can occur, which is highly dependent upon product inclusion rate. The holistic approaches adopted within this series of studies have seldom been performed on monogastric animals and thus provide valuable, transferable information for advancing knowledge in the application of SSF products, exogenous enzymes and lupins to farm animal feeds, in general.

Thesis (PhD) -- tellenbosch University, 2014.
ENGLISH ABSTRACT: This study is part of the continuing global research effort dedicated to finding alternative aquafeed ingredients, which not only replace fish meal and fish oil as sources of essential nutrients in aquafeeds, but also provide specialist functional properties when included in feeds. Due to constraints in supply of fish meal and fish oil originating from wild capture fisheries, the continually growing aquafeed industry requires new sources of raw materials for the production of high quality feeds. The aim of the study was to investigate the specialist functional properties of feed ingredients (with emphasis on immune-stimulation potential) derived from fish processing waste after enzymatic hydrolysis by endogenous proteolytic enzymes (autolysis). Further aims were to (i) quantify effects of these feed ingredients on production performance of two species relevant to the South African aquaculture industry, namely Mozambique tilapia Oreochromis mossambicus and South African abalone Haliotis midae, (ii) compare performance to commercially available enzymatically produced feed ingredients, and (iii) separate the functional effects of these fish processing waste derived feed ingredients from the acid used to preserve them against bacterial spoilage during the autolysis process. Oil recovered after autolysis of rainbow trout viscera proved to be an attractive feed ingredient due to favourable effects on the non-specific cellular immune function of both Mozambique tilapia and South African abalone. However, in South African abalone, increased immune function due to inclusion of fish oil was accompanied by a significant decrease in production performance. The inclusion of hydrolysed proteins, obtained by autolysis of fish waste, in aquaculture feeds also improved non-specific immunity and survival of Mozambique tilapia significantly – independently of the preserving acid – although the same was not observed for South African abalone. Production performance was dependent on dietary hydrolysed protein inclusion levels in both species; excessive inclusion resulted in decreased production performance. The performance of dietary hydrolysed protein from autolysis and those from commercial production processes were significantly different, possibly as a result of different raw material origins and production processes. It is further shown that formic acid can contribute to improved water stability in abalone feeds, a novel mode of action not previously described. The study concludes that the simple autolysis process for processing of fish waste can provide aquafeed ingredients with immune stimulatory potential, which can contribute to improved production performance in the Mozambique tilapia and the South African abalone. The result can contribute to improved sustainability of the aquafeed industry, through substitution of fish meal and fish oil derived from capture fisheries with processed fish waste components.
AFRIKAANSE OPSOMMING: Hierdie studie vorm deel van die voortdurende en wêreldwye soeke na nuwe akwakultuur voerbestanddele wat nie net vismeel en –olie kan vervang as bron van noodsaaklike voedingstowwe nie, maar wat ook gespesialiseerde funksionele eienskappe openbaar wanneer dit in akwavoere ingesluit word. As gevolg van beperkings in die voorsiening van vismeel en –olie afkomstig vanaf wilde visserye, word die voortdurend groeiende akwavoer bedryf genoodsaak om nuwe grondstowwe te benut vir die vervaardiging van hoë kwaliteit voere. Die doelwit van die studie was om moontlike gespesialiseerde funksionele eienskappe (met spesifieke klem op potensiële immuun-stimulasie) van voerbestanddele te ondersoek wat herwin is vanaf reënboogforel proseseringsafval, na ensiematiese hidrolise d.m.v. endogene ensieme teenwoordig in die afval (outolise). Verdere doelwitte was om (i) effekte op produksie prestasie van hierdie bestanddele te kwantifiseer in twee akwakultuur spesies relevant tot die Suid- Afrikaanse bedryf (naamlik die Mosambiekse kurper Oreochromis mossambicus en die Suid- Afrikaanse perlemoen Haliotis midae), (ii) om produksie prestasie te vergelyk met kommersieel beskikbare voerbestanddele voorberei d.m.v. ensiemtegnologie, en (iii) om die moontlike effekte van die voerbestanddele te skei van die van die sure gebruik om die bestanddele te preserveer tydens die outolitiese proses. Daar is bevind dat olie herwin na outolise van reënboogforel ingewande ‘n goeie voerbestanddeel is wat gunstige effekte op die nie-spesifieke, sellulêre immuniteit van beide Mosambiekse kurper en Suid-Afrikaanse perlemoen gehad het. In die Suid-Afrikaanse perlemoen het verbeterde immuunfunksie gepaard gegaan met ‘n verswakking in produksie prestasie. Die gehidroliseerde proteïen komponent van ge-outoliseerde prosesseringsafval het ook beduidende verbetering in nie spesifieke immuniteit en oorlewing van Mosambiekse kurper tot gevolg gehad - onafhanklik van die preserverende suur - maar dieselfde is nie in die Suid-Afrikaanse perlemoen waargeneem nie. Produksie prestasie was afhanklik van die insluitingsvlakke van gehidroliseerde proteïen in beide spesies en dit is bevind dat oormatige insluiting produksie nadelig beïnvloed. Prestasie van proteïen afkomstig van outolise en die van ‘n kommersiële produksieproses het beduidend verskil, moontlik as gevolg van verskillende grondstowwe en prosesseringstegnieke. Daar is verder vir die eerste keer getoon dat mieresuur ‘n beduidende verbetering in waterstabiliteit in sekere perlemoenvoere teweeg kan bring. Die studie kom tot die slotsom dat die eenvoudige outolise proses funksionele akwavoerbestanddele kan produseer wat kan bydra tot ‘n verbetering in produksie prestasie in die Mosambiekse kurper en Suid-Afrikaanse perlemoen. Die resultaat kan bydra tot verbeterde volhoubaarheid van die akwavoer bedryf, deur vismeel en –olie afkomstig van wilde visserye, te vervang.

In carnivorous fish farming industry, there are progressive increase demands for the finite resource of fish meal. A potential alternative to fish meal is to use legume meals which are free of enzyme inhibitors. In selected underutilised legumes the most effective processing method for eliminating trypsin (TIA), chymotrypsin (CIA) and alpha-amylase (AIA) inhibitors, without affecting the crude protein content, was investigated. These methods included soaking (S), wet heating (W), autoclaving (A) and dry freezing (D). No single method was effective at removing all the inhibitors. In all legumes tested, the combined processing methods which involved A were most effective in reducing CIA and AIA (p < 0.05), but not TIA. However, in adzuki bean both TIA and CIA were reduced by the D+A combined method (p < 0.05), whereas AIA of soybean and adzuki bean was decreased by combined methods of S+A (84.7 % and 99.3 % reduction respectively, p < 0.05) or A+D (99.1 % and 72.6 % reduction respectively, p < 0.05). All the processing methods retained 86.5 – 90.5 % of crude protein. Replacement of 10 % (w/w) of fish meal with D+A treated legume meal (either bambara groundnut or adzuki bean) for 28 days showed no significant difference in growth performance or inflammatory effects in Danio rerio or Lates calcarifer. Compared to Lates calcarifer given feed containing unprocessed adzuki bean meal, those on feed containing processed adzuki bean meal had increased hepatic gene expression of alanine aminotransferase (p < 0.01), indicating an enhanced ability to utilise amino acids. The project identified specific food processing methods which are effective at removing enzyme inhibitors in legumes, thereby facilitating the application of legumes as aquafeed ingredients. Future studies are required to examine what inclusion level of treated legume meal can promote growth performance in specific commercial fish species.

Research has been actively looking for alternative feed ingredients to reduce the reliance of the aquafeed industry on marine ingredients, namely fish meal (FM) and fish oil (FO). In this context, insects, in particular housefly (Musca domestica) and black soldier fly (BSF, Hermetia illucens) larvae, have been identified as promising candidates. Although a global insect farming industry is emerging, it is for now constrained by regulatory and technical bottlenecks that raise the question ‘where and how insect-based products could be integrated into aquaculture’. The literature indicated a high interspecies variability of the results when replacing FM with insect meals in fish diets and previous work failed to consider the existing challenges related to the insect production to demonstrate commercial relevance and applicability. In this thesis, maggot meals (MM) and frass (insect digestate) were assessed as strategic feed ingredients for two commercially important farmed species: Atlantic salmon, (Salmo salar) and Nile tilapia (Oreochromis niloticus), in their relevant contexts. Case studies showed that both housefly and BSF MM are high quality feed ingredients and suitable alternative to FM. Specifically, dietary inclusions of up to 200 g/kg of crude or defatted housefly larvae meal did not compromised the feed digestibility and utilisation and the growth performance and body composition of salmon parr (freshwater stage), compared to a FM-based control diet. Hormone (17α-methyltestosterone) treated diets containing between 250 and 1000 g/kg BSF or housefly meal were found as effective as a commonly used pure hormone-treated FM in sex-reversal process leading to 99.8 to 100% males, high survival and evenness of the fish produced. In a commercial diet for advanced nursing of Nile tilapia fingerlings, up to 80 g/kg BSF meal was included without impairing the fish performance and body composition; dietary inclusion was limited by the lipid content of the crude MM. Finally, BSF frass derived from brewery spent grains or processed food wastes were found more effective when used as soil bio-fertilisers with minimum application rate of 10.0 tonnes/ha or 5.0 tonnes/ha, respectively (for a spring onion culture), rather than supplemental feeds for tilapia farmed in semi-intensive conditions (fertilised pond). The study also indicated that site-specific conditions should be accounted to support appropriate and sustainable use of insect-based products but in any case, juvenile fish should be strategically targeted given their requirements. It is expected that this approach, could support the sustainable intensification of aquaculture and contribute more broadly to food security whilst contributing to the development of a circular economy.

Intensive and semi-intensive aquaculture systems are dependent on nutrient input either in the form of supplemental or complete feeds. Most complete diets still include high fish meal (FM) levels (≥10%). However, as the industry attempts to reduce its reliance on FM, feeds must now be formulated with much lower levels especially for omnivorous species such as tilapia. By 2015, mean FM inclusion in tilapia diets was projected to fall below 3% and be further reduced to 1% by 2020. In the global context of competition for crops, finding suitable plant-based replacers for FM and meeting the increasing demand for seafood, lower-cost and under-utilised plant feedstuffs are now receiving greater attention. The study was divided into three distinct components – field survey, growth experiments, and life cycle assessment. Field surveys were used to contextualise the growth experiments and assess commercialisation opportunities for multi-enzyme inclusion in tilapia feeds. Two sets of digestibility and growth experiments were designed to evaluate the feasibility of using high inclusions of plant-based ingredients sourced from locally available feedstuffs in Thailand to substitute FM at low inclusion levels (0 – 5%). The research evaluated the hypothesis regarding the potential of exogenous enzymes (protease, xylanase and phytase) to minimize anti-nutritional effects on nutrient digestibility of proteins, polysaccharides and phosphorus in tilapia. The research also assessed the secondary effects of enzyme supplementation on economic efficiency and life cycle environmental impacts. Tilapia is the second most cultured finfish globally and Thailand is the sixth largest producer. Based on the findings of the field survey, feeding practices of Thai tilapia farmers were confirmed to be diverse. Feed inputs included, but were not limited to, agro-industrial by-products (e.g. rice bran, corn bran etc.) and commercial diets. Commercial diets contained 15 – 30% crude protein and lower protein livestock diets (i.e. pig ration) were often used for supplemental feeding or “fattening”. The experimental low FM diets were therefore formulated as grow-out or “fattening” diets for semi-intensive green-water systems, a prominent feature (>60%) of Thai tilapia farming. In Phase 1, the digestibility experiment assessed the digestibility and growth in tilapia fed 0%, 3% and 5% FM diets with and without xylanase (0.385 g kg-1) and phytase (0.075 g kg-1). Performance decreased significantly with declining FM levels. No differences in feed intake, feed conversion ratio (FCR), specific growth rate (SGR) and weight gain were observed between the enzyme and control diets. Nevertheless, tilapia fed the enzyme supplemented 3% FM and control 5% FM performed similarly (P < 0.05). No enzyme-related effects were noticed for protein digestibility but phosphorus (P) digestibility improved by 9%, except at 0% FM level (P > 0.05). The enzymes had no apparent influence on nitrogen (N) retention contrary to previous studies, however, higher retention for P was observed. Villus length decreased with declining FM levels yet no improvements were seen in tilapia fed enzyme diets. In a simultaneous grow-out experiment, the six experimental diets were compared to an industry 10% FM standard. Conversion ratio was the lowest (1.66) in adult tilapia fed 10% FM diet however the enzyme supplemented 0% FM fed fish had a comparatively low FCR of 1.67. There were no significant enzyme-related effects on weight gain¸ SGR and protein efficiency. Proximal villi results were inconsistent. The cost of feed decreased with declining FM levels but increased with enzyme inclusion. Nevertheless, the economic returns per kg of whole fish produced were better using enzyme supplemented diets compared to the controls. Though the size of the effects on growth and nutrient utilisation were modest, the findings suggested that xylanase and phytase had some level of synergistic action on the targeted anti-nutrients. However, further research was required. In Phase 2, two control diets (2% FM, negative control (NC) and 10% FM, positive control (PC)) were compared with three enzyme supplemented 2% FM diets (NO-PRO, 0.385 g kg-1 xylanase and 0.075 g kg-1 phytase only; LO-PRO, xylanase + phytase + 0.2 g kg-1 protease and HI-PRO, xylanase + phytase + 0.4 g kg-1 PRO). Growth performances improved with enzyme supplementation compared to the NC (P < 0.05). Of the enzyme supplemented diets, the LO-PRO diet showed the highest improvements in weight gain (26%) and feed intake (19%), the latter comparing statistically to the 10% FM PC diet. The HI-PRO diet had the best FCR (1.88), again comparable to the PC (1.73). The NO-PRO diet had the highest protein, P, lipid and energy digestibility, suggesting no additive effect of protease on these coefficients. In terms of gut histomorphology, the LO-PRO and PC diets had the highest measurements and were statistically similar which may have explained similarities in feed intake. Compared to the NC, the HI-PRO diet produced the highest level of change in net profit due to gains in feeding efficiency however, the LO-PRO showed better improvements in terms of growth. Based on these findings, the ternary combination of protease with xylanase and phytase (LOPRO) has potential in limiting FM use for tilapia grow-out feeds, however, the economic efficiencies were still below that of a 10% FM diet. Future considerations for research should target the indigestible dietary components in order to optimise enzyme dosages and maximise the benefits of each enzymes. In conclusion, a comparative life cycle assessment (LCA) was used to evaluate the environmental impacts of low FM diets and commercial feeds associated with tilapia production in Thailand. The study showed that the low FM enzyme supplemented diets had lower impact potentials and were environmental superior to the average (10% FM) commercial standard. LCA modules are recommended for least-cost formulation programmes as an option going forward. Additionally, LCA can be used as a predictive tool to guide farmers, especially small-scale producers, on the potential impacts of feed input choices and feeding practices. This will ensure higher product quality but also demonstrate environmental responsibility on the part of aquafeed and fish producers to final seafood consumers.

The most abundant organic compound produced by plants is cellulose, however it has long been accepted that animals do not secrete the hydrolytic enzymes required for its degradation, but rely instead on cellulases produced by symbiotic microbes. The recent discovery of an endogenous cDNA transcript encoding a putative GHF9 endoglucanase in the parastacid crayfish Cherax quadricarinatus (Byrne et al., 1999) suggests that similar cellulase genes may have been inherited by a range of crustacean taxa. In this study, the evolutionary history of the C. quadricarinatus endoglucanase gene and the presence of additional GHF9 genes in other decapod species were investigated. The activity of endoglucanase and endoxylanase enzymes within several cultured decapod species were also compared. The evolutionary history of the C. quadricarinatus endoglucanase gene was assessed by comparing intron/exon structure with that of other invertebrate and plant GHF9 genes. The coding region of the gene was found to be interrupted by eleven introns ranging in size from 102-902 bp, the position of which was largely conserved in both termite and abalone GHF9 genes. These structural similarities suggest GHF9 genes in crustaceans and other invertebrate taxa share a common ancestry. In addition, two introns were observed to share similar positions in plant GHF9 genes, which indicates this enzyme class may have been present in ancient eukaryote organisms. The presence of GHF9 genes in C. quadricarinatus and various other decapod species was then explored via degenerate primer PCR. Two distinct GHF9 gene fragments were determined for C. quadricarinatus and several other Cherax and Euastacus parastacid freshwater crayfish species, and a single GHF9 gene fragment was also determined for the palaemonid freshwater prawn Macrobrachium lar. Phylogenetic analyses of these fragments confirmed the presence of two endoglucanase genes within the Parastacidae, termed EG-1 and EG-2. The duplication event that produced these two genes appears to have occurred prior to the evolution of freshwater crayfish. In addition, EG-2 genes appear to have duplicated more recently within the Cherax lineage. The presence of multiple GHF9 endoglucanase enzymes within the digestive tract of some decapod species may enable more efficient processing of cellulose substrates present in dietary plant material. Endoglucanase and endoxylanase enzyme activities were compared in several parastacid crayfish and penaeid prawn species using dye-linked substrates. Endoglucanase activity levels were higher in crayfish compared with prawn species, which corresponds with the known dietary preferences of these taxa. Endoglucanase temperature and pH profiles were found to be very similar for all species examined, with optimum activity occurring at 60°C and pH 5.0. These results suggest endoglucanase activity in penaeid prawns may also be derived from endogenous sources. Additional in vitro studies further demonstrated crayfish and prawn species liberate comparable amounts of glucose from carboxymethyl-cellulose, which indicates both taxa may utilise cellulose substrates as a source of energy. Endoxylanase temperature and pH profiles were also similar for all crayfish species examined, with optimal activity occurring at 50°C and pH 5.0. These results suggest xylanase activity in crayfish may originate from endogenous enzymes, although it is unclear whether this activity is derived from GHF9 enzymes or a different xylanase enzyme class. In contrast, no endoxylanase activity was detected in the three prawn species examined. Together, these findings suggest a wide range of decapod crustacean species may possess endogenous GHF9 endoglucanase genes and enzymes. Endoglucanases may be secreted by various decapod species in order to digest soluble or amorphous cellulose substrates present in consumed plant material. Further biochemical studies may confirm the presence and functional attributes of additional endoglucanase genes and enzymes in decapods, which may ultimately assist in the design of optimal plant based crustacean aquaculture feeds.

The world’s increasing demand for more sustainable food sources has brought more and more attention to aquaculture production in recent years. To overlap the dependence on pelagic fish and other plant-based options, insect meals are already being incorporated as alternative feed ingredient. However, the main source of polyunsaturated fatty acids (PUFA) in fish’s diets are still fish oil, obtained from overharvesting, mostly of pelagic fish, which competes directly with human consumption, and increasing the price of these ingredients and the need to find alternative solutions. Hermetia illucens, commonly known as black soldier fly, has a high protein content in the larval stage and the fatty acid content can be improved and modulated according to the substrate provided. In this work, it was incorporated the invasive macroalgae species Agarophyton vermiculophyllum, found widely in Ria de Aveiro, in the diet of H. illucens. The aim was to evaluate the bioconversion capacity of H. illucens and its ability to incorporate macroalgae PUFA in larval tissue when fed with diets with replacement levels of 25% and 50% of A. vermiculophyllum over four generations. Alongside, larvae grown parameters and conversion indexes were calculated and fatty acid profile was analysed by gas chromatography coupled to mass spectrometry (GC–MS). The results show the acceptability of the diet, since the larvae protein content was constant throughout the experience (38 to 46% of DM [dry matter]), independently of the substrate or generation. Mild deleterious effects were observed for 50% inclusion rate. The life cycle was slower in the first two generations, and the prepupal stage was reached earlier in the last two generations. In the diet formulation, the incorporation of 50% A. vermiculophyllum led to the occurrence of arachidonic (20:4) and docosahexaenoic acids (22:6). However, arachidonic acid was present in the larvae only in the third generation. A transgenerational decreased was observed in the saturated fatty acids content, defined mainly by the lauric acid content. An improvement in the PUFA content was reported, mostly due to linoleic acid abundance. Overall, the incorporation of A. vermiculophyllum in the diets of H. illucens larvae led to changes in its lipidic profile with increase in PUFA and reduction in saturated fatty acids. Larvae also demonstrated the ability to adapt to less suitable diets over several generations. Despite not being able to completely replace conventional n-3 PUFA sources in fish feed, black soldier fly larvae can be used as a protein source as well as other important fatty acids using an invasive macroalgae species as feeding substrate.
Nos últimos anos, o aumento da procura por fontes de alimentação mais sustentáveis, a nível mundial, aumentou a atenção dada à aquacultura. De forma a ultrapassar a dependência do peixe de pesca e de outras opções de base vegetal, o uso de insetos já é atualmente usado como um ingrediente alternativo em rações. No entanto, a principal fonte de ácidos gordos polinsaturados (PUFA) nas dietas dos peixes ainda é o óleo de peixe, obtido através da pesca excessiva, e que compete diretamente com a cadeia de consumo humano, aumentando o preço destes ingredientes e, consequentemente, a necessidade de encontrar soluções alternativas para eles. A Hermetia illucens, vulgarmente conhecida como mosca soldado negro, é rica em proteína, no seu estado larval, e o seu conteúdo em ácidos gordos pode ser modulado de acordo com o substrato fornecido. Neste trabalho, fez-se a incorporação da macroalga Agarophyton vermiculophyllum, uma espécie invasiva abundante na Ria de Aveiro, nas dietas da H. illucens. O objetivo foi avaliar a capacidade de bioconversão da macroalga por parte da H. illucens e estudar a possível incorporação dos PUFA presentes na macroalga nos tecidos larvares, quando dietas contendo 25% e 50% de A. vermiculophyllum foram fornecidas durante quatro gerações. Paralelamente, foram calculados parâmetros para avaliar o crescimento larval e os índices de conversão, e o perfil lipídico foi analisado por cromatografia gasosa acoplada a espetrometria de massa (GC-MS). Os resultados obtidos mostram que houve aceitabilidade da dieta, uma vez que o conteúdo proteico das larvas foi constante durante a experiência (38 a 46% DM [matéria seca]), independentemente do substrato ou geração. Leves efeitos negativos foram observados para 50% de incorporação, nomeadamente um ciclo de vida mais lento nas primeiras duas gerações, e o alcance do estado de prepupa mais cedo no caso das duas últimas gerações. Na formulação da dieta, a incorporação de 50% de A. vermiculophyllum resultou na ocorrência de ácido araquidónico (C20:4) e docosa-hexaenóico (C22:6). Contudo, a presença de ácido araquidónico nas larvas apenas foi observada na terceira geração. Uma diminuição transgeracional foi verificada no conteúdo de ácidos gordos saturados, atribuída maioritariamente às alterações na abundância do ácido láurico. É reportada uma melhoria no conteúdo em PUFA, devida à abundância do ácido linoleico. Em síntese, a incorporação de A. Vermiculophyllum nas dietas de larvas de H. illucens induziu mudanças no perfil lipídico, com um aumento no conteúdo de ácidos gordos polinsaturados e redução dos ácidos saturados. As larvas mostraram também capacidade transgeracional para se adaptar a dietas inusitadas. Embora não sejam adequadas para substituir fontes convencionais de n-3 PUFA na alimentação de peixes, as larvas da mosca soldado negro podem ser usadas como fonte de proteínas e de outros ácidos gordos importantes, aproveitando uma macroalga com comportamento invasivo como alimento.
Mestrado em Biologia Aplicada

碩士
國立臺灣海洋大學
水產養殖學系
100
In this study, the aquaculture production and aquafeed production data of Taiwan, China and other Asian countries were collected and analyzed. The competitive status of Taiwan’s aquafeed manufacturers was investigated and comparisons were conducted to understand the strength and weekness of Taiwan to China and Taiwan to global feed companies. This study will provide the important information for Taiwan fishery officials to propose the best development strategies for aquafeed industry。 Feed of eel, sea shrimp, milkfish, tilapia, sea bass, grouper and other marine fish are the important aquafeed in Taiwan. Due to the impact of shrimp virus in 1988, tiger shrimp related industries and the feed industry relocated rapidly to Southeast Asia and China, which indirectly led to the rapid establishment of the regional aquafeed industry. Shrimp and eel production showed rapid decline within 20 years. Although tilapia and marine fish feed increased, the total feed production can only be maintained at 400-500 thousand tons. Most of the aquafeed ingredient is dependent on imported sources, including fish meal which has a downward trend. The feed factories in Taiwan are toward specialization, large-scale pattern for the industry. The top ten ranking feed company’s production accounts for about 63% of total aquafeed production in Taiwan. World aquaculture production in 2010 amounted 50.9 million tons. Aquaculture production in Asia accounts for about 90% of global production, mainly from China and Southeast Asia. China is the largest aquaculture producer in the world, and the industry as a whole continued to grow. Southeast Asia farming style is extensive. Aquafeed industry is a potential market in Southeast Asia because the percentage of farmer who use compound feed is low. Although Taiwan companies came into major aquaculture-producing countries of Southeast Asia's to invest early, but in future they will face the compitition of local manufacturers, multinational feed group and the international raw material prices rise. With the increasingly fierce market, how to use our own strengths will become the key to manufacturer’s profit. The investigation results show that Taiwan's aquafeed market is saturated, and the average capacity utilization of all investigated company is only about 50%. Because of natural resources and policy constraints, the production is not easy to substantially increases in future. To face the challenge from China and other multinational feed groups, although we have the local advantage, however, it has to be very cautious for the Taiwanese government to change policy on permitting Chinese companies to build factories in Taiwan or importing feed from China, or implementing new environmental regulations, so that not to undermine the fragile stability of the market order in Taiwan. Taiwan feed company in Asia, except China still have competitive strength, but they must continue to enhance the ability of using cheap raw materials and operating in grobal. From the survey results of this study, aquafeed manufacturers suggest that label of crude composition and ingredents informatiom is not applicable. Because of different product interest in manufacturers, so they have several different opinions about the regulation. Hence, there is an urging need to refer the specification of the feed label from international advanced countries. Other than that, involvement from feed industry, government and academic experts is needed to discuss how to amend the relevant specification.

A soja é uma das oleaginosas mais consumidas no mundo. Entre os principais subprodutos da transformação industrial da soja destaca-se o okara. Este subproduto, resultante da produção de bebidas de soja, representa ainda um problema ambiental devido às altas quantidades produzidas. Adicionalmente, o seu elevado teor de humidade (~ 80%) dificulta sua conservação e, consequentemente, a sua posterior utilização. No entanto, apesar da sua perecibilidade, o okara possui uma composição nutricional rica em proteínas, lípidos e fibras bem como elevados teores de compostos com potencial bioativo como as isoflavonas. Neste contexto, o principal objetivo deste programa de doutoramento foi encontrar alternativas para aumentar a estabilidade do okara, através de processos térmicos ou biotecnológicos (nomeadamente hidrólise enzimática e fermentação com bactérias probióticas), por forma a melhorar as propriedades biológicas do okara tendo em vista a sua utilização na alimentação humana bem como na animal, mais especificamente na aquacultura. A primeira parte do trabalho incidiu no estudo do impacto de diferentes temperaturas na secagem do okara (80 ºC/5 h e 200 ºC/1 h). De um ponto de vista microbiológico, em ambas as amostras foi verificada uma redução na contaminação microbiana no tempo inicial. Adicionalmente, no okara seco a 200 ºC foi observada uma redução da atividade dos inibidores de tripsina, no entanto, esta amostra também apresentou uma maior oxidação lipídica durante o armazenamento. De seguida, estudou-se a influência de um processo de autoclavagem (1 atm, 121 ºC por 15 min) prévio à secagem a 65 ºC (AOK) em comparação com o okara seco não autoclavado (NAOK), tendo-se observado que o processo de autoclavagem, além de reduzir a atividade dos inibidores de tripsina (0.86 mg TUI/ mg de amostra seca), manteve as características da farinha de okara durante o armazenamento. Na segunda parte do trabalho foram estudadas diferentes condições (tempo e concentração de enzima) na hidrólise enzimática das farinhas de okara (NAOK e AOK) utilizando duas enzimas, Alcalase (AL) e protéases de Cynara cardunculus (CY). Os resultados mostraram que o processo térmico facilitou o ataque enzimático resultando numa elevada atividade anti-hipertensiva para ambos os hidrolisados (9.97 e 54.30 μg de proteína/mL, AL e CY, respetivamente) bem como antioxidante, em particular para a AL. Este estudo também permitiu a identificação de novas sequências peptídicas para ambas as enzimas. Com base nos resultados anteriores, nomeadamente a atividade anti-hipertensiva, iniciou-se a terceira componente deste iv trabalho, i.e. o desenvolvimento de bebidas fermentadas utilizando okara fresco previamente hidrolisado com CY. Para elaborar as bases da bebida, aos hidrolisados de okara foi adicionada frutose (6% m/v) e frutoligossacarídeos (FOS) (2% m/v), sendo a mistura resultante fermentada utilizando duas bactérias probióticas Bifidobacterium animalis Bb-12 e Lactobacillus rhamnosus R11, individualmente e em mistura. As bebidas fermentadas de okara foram analisadas ao longo de 28 dias de armazenamento com os níveis de células viáveis mantendo-se estáveis durante esse período. Adicionalmente, quando as bebidas de okara foram submetidas ao sistema gastrointestinal (in vitro), verificou-se um aumento das atividades antioxidante e anti-hipertensivas (IC50), o que se poderá traduzir numa maior bioacessibilidade. No entanto, sensorialmente as bebidas fermentadas não foram bem aceites pelos participantes, que indicaram uma acidez elevada e doçura insuficiente. A última parte deste trabalho consistiu na incorporação das farinhas, previamente descritas, em dietas para uma espécie de peixe herbívora, a Tilápia do Nilo (Oreochromis niloticus). Começou por se avaliar in vivo a digestibilidade de seis farinhas: NAOK, AOK, okara hidrolisado com AL e autoclavado (ALOK), okara hidrolisado com CY e autoclavado (CYOK), CYOK fermentado com L. rhamnosus R11 (CYR11OK) e CYOK fermentado com B. animalis Bb-12 (CYB12OK). Seguidamente, as farinhas de okara que apresentaram digestibilidades mais elevadas (AOK e CYOK) foram incorporadas em dietas para Tilápia do Nilo (a 10 e 20%) à custa de ingredientes vegetais (farinhas de soja, milho e trigo) de forma a avaliar o seu impacto no crescimento e utilização de nutrientes ao longo de um ensaio de crescimento de 10 semanas. De um modo geral, os resultados mostraram que a incorporação das farinhas de okara selecionadas (até 20%) não alteram significativamente a performance de crescimento nem a utilização de nutrientes da Tilápia do Nilo. Considerando todos os resultados obtidos, é possível concluir que, com um tratamento térmico adequado é possível melhorar a qualidade nutricional do okara e mantê-lo estável durante o armazenamento. Adicionalmente, a hidrólise enzimática e a fermentação podem contribuir para melhorar as características nutricionais e funcionais da okara, quando se consideram aplicações na nutrição humana. Relativamente ao uso de okara na aquacultura, este pode ser incorporado até 20% em dietas para a Tilápia do Nilo, substituindo outros ingredientes de origem vegetal e diminuindo os custos de produção, sem que se verifique qualquer efeito adverso no crescimento dos peixes nem na sua composição corporal.
Soybean is one of the most consumed oilseeds in the world. Among the main industrial by-products resulting from soya processing, okara can be highlighted. This by-product, resulting from the production of soy beverages, is still an environmental problem due to the high quantities produced. In addition, its high moisture content (~ 80%) makes it difficult to preserve and, consequently, its subsequent use However, despite its high instability, okara has an interesting nutritional composition (it is rich in fiber, protein and lipids) as well as significant levels of antioxidant compounds, mainly isoflavones. In this context, the general objective of this PhD programme was to increase the stability of okara (through thermal and/or biotechnological processes such as enzymatic hydrolysis and fermentation with probiotic bacteria) and improve its biological properties towards the development of new food and aquafeed solutions. Firstly, the impact of different drying temperatures (80 ºC/5 h (D80) and 200 ºC/1 h (D200)) was studied, with all samples showing a reduction of microbial contamination afterwards. D200 exhibited a reduction of trypsin inhibitors’ activity, however it also showed a stronger increase in lipid oxidation than D80 during storage. Afterwards, the influence of autoclaving (1 atm, 121 ºC and 15 min) was evaluated with the autoclaved okara flours (AOK) exhibiting reduced trypsin inhibitors’ activity (0.86 mg TUI/ mg dry sample) and maintaining their characteristics during the storage better than the non-autoclaved flours (NAOK). The second part of the hereby proposed work focused on the study of different hydrolysis conditions (time and enzyme concentration) upon the okara flours (NAOK and AOK) using two enzymes, alcalase (AL) and proteases from Cynara cardunculus (CY). The results showed that the thermal process facilitated enzymatic attack resulting in high antihypertensive activity for both hydrolysates (9.97 and 54.30 μg protein / mL, AL and CY respectively) as well as antioxidant, in particular for AL. This study also allowed the identification of new peptide sequences for both enzymes. Based on the previous results, namely the antihypertensive activity, the third stage focused on the development of fermented beverages using fresh okara previously hydrolyzed with CY. The hydrolysates, supplemented with fructose (6% w/v) and FOS (2% w/v), were fermented with two probiotic bacteria: Bifidobacterium animalis Bb-12, Lactobacillus rhamnosus R11 and a combination of the two. The resulting beverages were analyzed over 28 days of storage with the bacteria remaining viable during this vi period. Moreover, when subjected to a simulated gastrointestinal system, the antioxidant and antihypertensive activities (IC50) of the beverages increased, hinting at an improvement of the bioaccessibility of bioactive components. However, despite the interesting bioactivity results, sensory wise the fermented beverages were not so well accepted with the participants of the study remarking on the fermented beverages’ high acidity and low sweetness. The last part of this PhD program focused on the incorporation of the different okara flours, obtained using the different processes described above, in Nile Tilapia (Oreochromis niloticus) diets. Firstly, a digestibility trial was performed in vivo with six different okara flours: NAOK, AOK, okara hydrolyzed with AL and autoclaved (ALOK), okara hydrolyzed with CY and autoclaved (CYOK), CYOK fermented with L. rhamnosus R11 (CYR11OK) and CYOK fermented with B. animalis Bb-12 (CYB12OK). Afterwards, the ingredients with the highest apparent digestibility coefficients values (AOK and CYOK) were included in diets for Nile Tilapia (at 10 and 20%), at the expense of other vegetable sources (soybean, wheat and corn meals), in a 10 weeks growth trial. In general, results showed that the dietary inclusion of okara up to 20% did not significantly affect the growth performance or nutrient utilization of Nile tilapia. Overall, considering all the results obtained, it can be concluded that a correct heat treatment can result not only in an increase of the nutritional quality of okara but also improve the storage time of this by-product. In addition, the biotechnological processes studied (enzyme mediated hydrolysis and fermentation by probiotic microorganisms) may also contribute to the improvement of the nutritional and functional characteristics of okara when considering food applications for human consumption. Regarding the potential use of okara in aquaculture, the hereby described results hint that it can be successfully incorporated into aquafeed formulations for Nile Tilapia, replacing other, more expensive ingredients of plant origin, therefore reducing production costs without having any adverse effects on fish growth or whole body composition.

碩士
國立臺灣海洋大學
水產養殖學系
99
Functional Complex Beneficial Microorganisms (FCBM) is not only be classified as photosynthetic bacteria, nitrifying bacteria, and some probiotics, but also includes other microorganisms, such as Trichoderma and Monascus purpureus. In aquaculture, CBM can be used in different way, such in water processing, disease prevention, feed potentiation, and nutrient regulation. Nowadays, people are try to substitute expensive animal protein feed with cheaper plant protein in feed used in aquaculture. Plant-desired protein feed, however, contains fewer nutrients and more toxic compounds, when compared with animal protein feed. By conducting anaerobic solid fermentation of isothiocyanate (ITC), oxazolidinethione, (OZT), and phytic acid, which are remove from canola meal, CBM also can increase the plant-desired protein utilization in Oreochromis niloticus. In this study ,the optimal condition for the solid state fermentation of CBM was deterimented. CBM and mixed canola meal with a ratio of 0.8:1, 1:1, and 1.2:1 and subsequently fermention for 7, 14, 21, 28, 35 days and 5, 10, 15, 20, 25, 30 days, respectively. The results showed that the CBM mixture with canola meal on the ratio 0.8:1 has the lowest in toxic compounds and anti-nutritional factors. The result of canola meal was fermented under 25°C, 30°C, 35°C, 40°C, for 5, 10, 15, 20, 25, 30 days indicated that detoxification was most effectively at 30°C. The fermentation duration was 25 days detoxification with most effectively. Small peptides increased 10-fold when fermented for 25 days. The amount of isothiocyanate, oxazolidinethione, and phytic acid decreased 68%, 75%, and 81%, respectively and after 25 days fermentation. Afterwards, we used canola meal fermented and unfermented canola meal for 25 days to substitute 30%, 60%, and 100% soy meal substitute soy meal of 30%, 60%, and 100% for ten weeks feeding. The result showed that no significant difference between using 60% canola meal and control group after 10 weeks. In addition to, unfermented canola meal to substitute soybean meal 30% at most, and liver enlarged,vacuoles and necrosis can be observed in the liver biopsy. Furthermore, we used fermented canola meal and soy meal to substitute fish meal of 10%, 30%, and 50%. The result revealed that 10% canola meal has better growth performene than the group with no substitution. Although Oreochromis niloticu did not grow well, the liver biopsy was normal, or the liver enlarged,vacuoles and necrosis was reduced by using canola meal of 50%. This result suggested that the nutrients of canola meal increased and the toxic compounds and anti-nutritional factors were reduced significantly after fermented with CBM.