Journal ArticleDOI
LC-PUFA Biosynthesis in Rainbow Trout is Substrate Limited: Use of the Whole Body Fatty Acid Balance Method and Different 18:3n-3/18:2n-6 Ratios
Thanongsak Thanuthong,Thanongsak Thanuthong,David S. Francis,Shyamalie D. Senadheera,Paul L. Jones,Giovanni M. Turchini +5 more
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In this paper, the whole-body fatty acid balance method demonstrated a clear trend of progressively reduced fatty acid bioconversion activity along the n-3 and n-6 pathways, up to the production of 20:5n-3 or 20:4n-6, respectively.Abstract:
Five experimental diets with constant total C18 PUFA and varying 18:3n-3/18:2n-6 ratios were fed to rainbow trout over an entire production cycle. The whole-body fatty acid balance method demonstrated a clear trend of progressively reduced fatty acid bioconversion activity along the n-3 and n-6 pathways, up to the production of 20:5n-3 and 20:4n-6, respectively. This suggests that the pathway exhibits a “funnel like” progression of activity rather than the existence of a single rate limiting step. The production of 22:5n-3 and 22:6n-3 was more active than that of 20:5n-3. However, despite this trend in reduced apparent in vivo net enzyme activity, the efficiency of the various bioconversion steps (measured as % of bioconverted substrate) confirmed an opposing trend. A 3.2-fold higher Δ-6 desaturase affinity towards 18:3n-3 over 18:2n-6 and an 8-fold greater Δ-5 desaturase affinity towards 20:4n-3 over 20:3n-6 were recorded. The main results of the study were that (1) rainbow trout are quite efficient at bioconverting 18:3n-3 to 22:6n-3, and (2) the LC-PUFA biosynthetic pathway is substrate limited. Fillet n-3 LC-PUFA concentrations increased with the increasing dietary supply of 18:3n-3. Despite an almost identical dietary supply of n-3 LC-PUFA, originating from the fish meal fraction of the diets, the fillets of trout fed the diet richest in 18:3n-3 were 2-fold higher in n-3 LC-PUFA than fish fed low 18:3n-3 diets. Nevertheless, fillets of trout fed a fish oil control diet contained more than double the amount of n-3 LC-PUFA compared to fish fed the diets richest in 18:3n-3.read more
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Book ChapterDOI
The lipids
Giovanni M. Turchini,David S. Francis,Zhenduo Du,Rolf Erik Olsen,Einar Ringø,Douglas R. Tocher +5 more
TL;DR: In this paper , a general overview of lipid biochemistry is presented, followed by a series of broader aspects of fish lipid nutrition in aquaculture, analyzing resource availability, challenges and opportunities, consumers' nutritional expectations, and the interactions between lipids in Aquaculture feeds and the environment.
Journal ArticleDOI
Full substitution of fish oil with camelina (Camelina sativa) oil, with partial substitution of fish meal with camelina meal, in diets for farmed Atlantic salmon (Salmo salar) and its effect on tissue lipids and sensory quality
TL;DR: This was the first study to use CO as a complete FO replacement in diets for farmed Atlantic salmon and total lipid in salmon flesh fed a diet with CO, SEFM and CM was significantly higher than FO flesh.
Journal ArticleDOI
Uncoupling EPA and DHA in Fish Nutrition: Dietary Demand is Limited in Atlantic Salmon and Effectively Met by DHA Alone
James A. Emery,Fernando Norambuena,Jesse T. Trushenski,Jesse T. Trushenski,Giovanni M. Turchini +4 more
TL;DR: Results clearly indicate EPA and DHA are metabolized differently by Atlantic salmon, and suggest that the n-3 LC-PUFA dietary requirements of Atlantic salmon may be lower than reported and different, if originating primarily from EPA or DHA.
Journal ArticleDOI
The effects of fish oil replacement by vegetable oils on growth performance and fatty acid profile of rainbow trout: Re-feeding with fish oil finishing diet improved the fatty acid composition
TL;DR: Results showed that total and/or partial replacement of FO did not negatively affect growth and feed utilization, and feeding VOs significantly reduced body contents of arachidonic acid (ARA), eicosapentaenoic acid (EPA) and docosahexaenoic Acid (DHA) to a lower degree than their reduction in the diet.
Journal ArticleDOI
Changes in Tissue Lipid and Fatty Acid Composition of Farmed Rainbow Trout in Response to Dietary Camelina Oil as a Replacement of Fish Oil
TL;DR: Compound-specific stable isotope analysis (CSIA) confirmed that the δ13C isotopic signature of DHA in CO fed trout shifted significantly compared toDHA in FO fed trout, indicating mixing of a terrestrial and isotopically lighter ALA in the CO diet.
References
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Journal ArticleDOI
Metabolism and Functions of Lipids and Fatty Acids in Teleost Fish
TL;DR: This review attempts to summarize the present state of knowledge of various aspects of the basic biochemistry, metabolism, and functions of fatty acids, and the lipids they constitute part of, in fish, seeking where possible to relate that understanding as much to fish in their natural environment as to farmed fish.
Journal ArticleDOI
Global overview on the use of fish meal and fish oil in industrially compounded aquafeeds: Trends and future prospects
Albert G. J. Tacon,Marc Metian +1 more
TL;DR: The finfish and crustacean aquaculture sector is still highly dependent upon marine capture fisheries for sourcing key dietary nutrient inputs, including fish meal and fish oil, which is particularly strong within compound aquafeeds for farmed carnivorous finfish species and marine shrimp.
Journal ArticleDOI
Essential fatty acids in health and chronic disease
TL;DR: Alpha-linolenic acid, found in green leafy vegetables, flaxseed, rapeseed, and walnuts, desaturates and elongates in the human body to EPA and DHA and by itself may have beneficial effects in health and in the control of chronic diseases.
Journal ArticleDOI
Fish oil replacement in finfish nutrition
TL;DR: This review attempts to compile all principal information available regarding the effects of fish oil replacement for the diets of farmed finfish, analysing the findings using a comparative approach among different cultured fish species.
Journal ArticleDOI
On the acid digestion method for the determination of chromic oxide as an index substance in the study of digestibility of fish feed.
TL;DR: In this article, the spectral absorption curves of solutions prepared by the wet acid digestion of chromic oxide were examined to study the digestibility of feed by marine fishes; the results of the present work showed that the following procedures were adequate for the study of digestibility.