scholarly journals Endogenous production of n-3 long-chain PUFA from first feeding and the influence of dietary linoleic acid and the α-linolenic:linoleic ratio in Atlantic salmon (Salmo salar)

2019 ◽  
Vol 122 (10) ◽  
pp. 1091-1102 ◽  
Author(s):  
Matthew Sprague ◽  
Gong Xu ◽  
Monica B. Betancor ◽  
Rolf E. Olsen ◽  
Ole Torrissen ◽  
...  

AbstractAtlantic salmon (Salmo salar) possess enzymes required for the endogenous biosynthesis of n-3 long-chain PUFA (LC-PUFA), EPA and DHA, from α-linolenic acid (ALA). Linoleic acid (LA) competes with ALA for LC-PUFA biosynthesis enzymes leading to the production of n-6 LC-PUFA, including arachidonic acid (ARA). We aimed to quantify the endogenous production of EPA and DHA from ALA in salmon fed from first feeding on diets that contain no EPA and DHA and to determine the influence of dietary LA and ALA:LA ratio on LC-PUFA production. Salmon were fed from first feeding for 22 weeks with three diets formulated with linseed and sunflower oils to provide ALA:LA ratios of approximately 3:1, 1:1 and 1:3. Endogenous production of n-3 LC-PUFA was 5·9, 4·4 and 2·8 mg per g fish and that of n-6 LC-PUFA was 0·2, 0·5 and 1·4 mg per g fish in salmon fed diets with ALA:LA ratios of 3:1, 1:1 and 1:3, respectively. The ratio of n-3:n-6 LC-PUFA production decreased from 27·4 to 2·0, and DHA:EPA ratio increased and EPA:ARA and DHA:ARA ratios decreased, as dietary ALA:LA ratio decreased. In conclusion, with a dietary ALA:LA ratio of 1, salmon fry/parr produced about 28 μg n-3 LC-PUFA per g fish per d, with a DHA:EPA ratio of 3·4. Production of n-3 LC-PUFA exceeded that of n-6 LC-PUFA by almost 9-fold. Reducing the dietary ALA:LA ratio reduced n-3 LC-PUFA production and EPA:ARA and DHA:ARA ratios but increased n-6 LC-PUFA production and DHA:EPA ratio.

2018 ◽  
Vol 119 (12) ◽  
pp. 1378-1392 ◽  
Author(s):  
Mónica B. Betancor ◽  
Keshuai Li ◽  
Valentin S. Bucerzan ◽  
Matthew Sprague ◽  
Olga Sayanova ◽  
...  

AbstractFacing a bottleneck in the growth of aquaculture, and a gap in the supply and demand of the highly beneficial n-3 long-chain PUFA (LC-PUFA), sustainable alternatives to traditional marine-based feeds are required. Therefore, in the present trial, a novel oil obtained from a genetically engineered oilseed crop, Camelina sativa, that supplied over 25 % n-3 LC-PUFA was tested as a sole dietary-added lipid source in Atlantic salmon (Salmo salar) feed. Three groups of fish were fed three experimental diets for 12 weeks with the same basal composition and containing 20 % added oil supplied by either a blend of fish oil and rapeseed oil (1:3) (COM) reflecting current commercial formulations, wild-type Camelina oil (WCO) or the novel transgenic Camelina oil (TCO). There were no negative effects on the growth, survival rate or health of the fish. The whole fish and flesh n-3 LC-PUFA levels were highest in fish fed TCO, with levels more than 2-fold higher compared with those of fish fed the COM and WCO diets, respectively. Diet TCO had no negative impacts on the evaluated immune and physiological parameters of head kidney monocytes. The transcriptomic responses of liver and mid-intestine showed only mild effects on metabolism genes. Overall, the results clearly indicated that the oil from transgenic Camelina was highly efficient in supplying n-3 LC-PUFA providing levels double that obtained with a current commercial standard, and similar to those a decade ago before substantial dietary fishmeal and oil replacement.


2019 ◽  
Vol 121 (10) ◽  
pp. 1108-1123 ◽  
Author(s):  
Thomas S. Mock ◽  
David S. Francis ◽  
Matthew K. Jago ◽  
Brett D. Glencross ◽  
Richard P. Smullen ◽  
...  

AbstractA more efficient utilisation of marine-derived sources of dietary n-3 long-chain PUFA (n-3 LC PUFA) in cultured Atlantic salmon (Salmo salar L.) could be achieved by nutritional strategies that maximise endogenous n-3 LC PUFA synthesis. The objective of the present study was to quantify the extent of n-3 LC PUFA biosynthesis and the resultant effect on fillet nutritional quality in large fish. Four diets were manufactured, providing altered levels of dietary n-3 substrate, namely, 18 : 3n-3, and end products, namely, 20 : 5n-3 and 22 : 6n-3. After 283 d of feeding, fish grew in excess of 3000 g and no differences in growth performance or biometrical parameters were recorded. An analysis of fatty acid composition and in vivo metabolism revealed that endogenous production of n-3 LC PUFA in fish fed a diet containing no added fish oil resulted in fillet levels of n-3 LC PUFA comparable with fish fed a diet with added fish oil. However, this result was not consistent among all treatments. Another major finding of this study was the presence of abundant dietary n-3 substrate, with the addition of dietary n-3 end product (i.e. fish oil) served to increase final fillet levels of n-3 LC PUFA. Specifically, preferential β-oxidation of dietary C18n-3 PUFA resulted in conservation of n-3 LC PUFA from catabolism. Ultimately, this study highlights the potential for endogenous synthesis of n-3 LC PUFA to, partially, support a substantial reduction in the amount of dietary fish oil in diets for Atlantic salmon reared in seawater.


1987 ◽  
Vol 44 (2) ◽  
pp. 337-347 ◽  
Author(s):  
V. A. Pepper ◽  
T. Nicholls ◽  
N. P. Oliver

Atlantic salmon fry (Salmo salar) obtained from an artificial spawning channel and a deep-substrate incubator, were reared in mesh "troughs" in an artificial rearing channel and in floating lake cages. Fry placed in the lake cages were able to complete their first feeding phase on a diet of natural lake zooplankton but growth performance was improved when artifical diets were used to supplement natural food. Parr fed selectively on Daphnia catawba and mature Epischura lacustris. Parr reared in the mesh troughs were hand-fed a commercial diet. The 90-d average release weight ranged from 1.8 to 3.1 g for parr from the mesh troughs and from 0.9 to 3.1 g for parr from the lake cages. Growth of parr in these experiments resulted in an average weight advantage of approximately 2.3–4.5 times over parr captured from natural riverine habitat at the end of the experiment. Overall swim-up fry to fall-fingerling survival from these experiments was 52% in 1983 and 76% in 1984. Survival and growth varied inversely with density in the mesh trough experiments.


2011 ◽  
Vol 105 (12) ◽  
pp. 1772-1782 ◽  
Author(s):  
Mohamed B. Codabaccus ◽  
Andrew R. Bridle ◽  
Peter D. Nichols ◽  
Chris G. Carter

Vegetable oils (VO) have become the predominant substitute for fish oil (FO) in aquafeeds; however, the resultant lower content of n-3 long-chain ( ≥ C20) PUFA (n-3 LC-PUFA) in fish has put their use under scrutiny. The need to investigate new oil sources exists. The present study tested the hypothesis that in Atlantic salmon (Salmo salar L.), a high intake of stearidonic acid (SDA) from Echium oil (EO) would result in increased n-3 LC-PUFA biosynthesis due to a lower requirement for Δ6 desaturase. Comparisons were made with fish fed on diets containing rapeseed oil (RO) and FO in freshwater for 112 d followed by 96 d in seawater. EO fish had higher whole-carcass SDA and eicosatetraenoic acid (ETA) in freshwater and prolonged feeding on the EO diet in seawater resulted in higher SDA, ETA, EPA and docosapentaenoic acid (DPA) compared with RO fish. Fatty acid mass balance of freshwater fish indicated higher biosynthesis of ETA and EPA in EO fish compared with fish fed on the other diets and a twofold increase in n-3 LC-PUFA synthesis compared with RO fish. In seawater, n-3 biosynthetic activity was low, with higher biosynthesis of ETA in EO fish and appearance of all desaturated and elongated products along the n-3 pathway. SDA-enriched VO are more suitable substitutes than conventional VO from a human consumer perspective due to the resulting higher SDA content, higher total n-3 and improved n-3:n-6 ratio obtained in fish, although both VO were not as effective as FO in maintaining EPA and DHA content in Atlantic salmon.


2015 ◽  
Vol 4 ◽  
Author(s):  
Katerina Kousoulaki ◽  
Tone-Kari Knutsdatter Østbye ◽  
Aleksei Krasnov ◽  
Jacob Seilø Torgersen ◽  
Turid Mørkøre ◽  
...  

AbstractMicroalgae, as primary producers of EPA and DHA, are among the most prominent alternative sources to fish oil for n-3 long-chain PUFA in animal and human nutrition. The present study aimed to assess technical, nutritional and fish health aspects of producing n-3-rich Atlantic salmon (Salmo salar) fish fillets by dietary supplementation of increasing levels of a DHA-producing Schizochytrium sp. and reduced or without use of supplemental fish oil. Atlantic salmon smolt were fed diets with graded levels of microalgae for 12 weeks, during which all fish showed high feed intake rates with postprandial plasma leptin levels inversely correlating with final mean fish body weights. Fish performance was optimal in all experimental treatments (thermal growth coefficient about 4·0 and feed conversion ratio 0·8–0·9), protein digestibility was equal in all diets, whereas dietary lipid digestibility inversely correlated with the dietary levels of the SFA 16 : 0. Fillet quality was good and similar to the control in all treatments in terms of n-3 long-chain PUFA content, gaping, texture and liquid losses during thawing. Histological fluorescence staining and immunofluorescence analysis of salmon intestines (midgut: base of intestine and villi) revealed significant effects on slime, goblet cell production and inducible nitric oxide synthase (iNOS) activity with increasing levels of dietary Schizochytrium sp. supplementation. Microarray analysis did not reveal any signs of toxicity, stress, inflammation or any other negative effects from Schizochytrium sp. supplementation in diets for Atlantic salmon.


2002 ◽  
Vol 8 (1) ◽  
pp. 7-13 ◽  
Author(s):  
R. ØRNSRUD ◽  
I. E. GRAFF ◽  
S. HØIE ◽  
G. K. TOTLAND ◽  
G.-I. HEMRE

1990 ◽  
Vol 21 (4) ◽  
pp. 435-441 ◽  
Author(s):  
S. O. STEFANSSON ◽  
R. NORTVEDT ◽  
T. J. HANSEN ◽  
G. L. TARANGER

2007 ◽  
Vol 99 (1) ◽  
pp. 168-174 ◽  
Author(s):  
Francesca L. Crowe ◽  
C. Murray Skeaff ◽  
Timothy J. Green ◽  
Andrew R. Gray

A higher proportion of n-3 long-chain PUFA in tissue lipids has been associated with a lower risk of CVD and some cancers. Diet is an important predictor of n-3 long-chain PUFA composition; however, the importance of non-dietary factors such as sex and age is unclear. We measured the proportion of n-3 long-chain PUFA in serum phospholipid, cholesterol ester and TAG of 2793 New Zealanders 15 years or older who participated in the 1997 National Nutrition Survey to determine differences by sex and age. Women had lower proportions of EPA and docosapentaenoic acid in phospholipid, by 0·07 (P = 0·004) and 0·10 (P < 0·001) mol%, respectively, and a higher proportion of DHA by 0·16 mol% (P = 0·001) compared with men. Intake of fish fat did not differ between men and women. There was a positive association between age and the proportion of EPA and DHA in phospholipid (P < 0·001). The sex differences in EPA and DHA were similar at all ages. Similar sex and age differences in serum cholesterol ester n-3 long-chain PUFA were found; only age differences were found in serum TAG. Sex and age differences in n-3 long-chain PUFA occur in the general population. Men and women may need to be considered separately when examining the association between disease risk and biomarkers of n-3 fatty acids.


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