Influence of dietary conjugated linoleic acid (CLA) on lipid and fatty acid composition in liver and flesh of Atlantic salmon (Salmo salar)

Abstract

The aim of the present study was to determine the effects of conjugated linoleic acid (CLA) on lipid and fatty acid metabolism in Atlantic salmon. The overall objective being to test the hypotheses that CLA has beneficial effects in salmon including growth enhancement, improved flesh quality through decreased adiposity and lipid deposition thereby minimising detrimental effects of feeding high fat diets, and increased nutritional quality through increased levels of beneficial fatty acids including n-3 highly unsaturated fatty acids (HUFA) and CLA itself. Salmon smolts were fed diets containing two levels of fish oil (low, ~18% and high, ~34%) containing three levels of CLA (a 1:1 mixture of 9-cis,trans-11 and trans-10,cis-12. at 0, 1 and 2% of diet) for 3 months and the effects on growth performance, liver and muscle (flesh) lipid contents and class compositions, and fatty acid compositions determined. The diets were also specifically formulated to investigate whether the effects of CLA, if any, were more dependent upon absolute content of CLA in the diet (as percentage of total diet) or the relative level of CLA to other fatty acids. Dietary CLA in salmon smolts had no effect on growth parameters or biometric parameters. However, there was a clear trend of increased total lipid and triacylglycerol contents in both liver and flesh in fish fed CLA, particularly in fish fed the high oil diets. Finally, CLA was incorporated into tissue lipids, with levels in flesh being 2-fold higher than in liver, but importantly, incorporation in liver was at the expense of saturated and monounsaturated fatty acids whereas in flesh it was at the expense of n-3HUFA.3

Effect of dietary conjugated linoleic acid (CLA) on growth performance, body composition and hepatic intermediary metabolism in juvenile yellow catfish Pelteobagrus fulvidraco

“…The different effects of CLA obtained in our study and other reports may be attributable to differences in metabolic rate, administered dose of dietary CLA, relative proportion of each isomer in a dietary CLA mixture, or length of the feeding period, as suggested by Terpstra (2001). In respect of whole body composition, dietary CLA inclusion up to 2% did not significantly influence moisture and crude protein contents of whole body, in agreement with several studies with fish (Twibell et al, 2000(Twibell et al, , 2001Berge et al, 2004;Kennedy et al, 2005;Manning et al, 2006;Valente et al, 2007a,b). In the present study, dietary CLA reduced lipid content in whole body and liver, similar to those in hybrid striped bass and in yellow perch (Twibell et al, 2000(Twibell et al, , 2001, but in contrast with channel catfish, rainbow trout and Nile tilapia (Twibell and Wilson, 2003;Yasmin et al, 2004;FigueiredoSilva et al, 2005;Bandarra et al, 2006;dos Santos et al, 2010).…”

“…Similarly, Bandarra et al (2006) reported that lipid content in viscera showed a decrease with CLA inclusion in fish fed the 0.5% diet compared to those fed the control. In contrast, dietary CLA did not affect CF (Kennedy et al, 2007;Valente et al, 2007a;Ramos et al, 2008) and VSI in several studies (Figueiredo-Silva et al, 2005;Kennedy et al, 2005). The different effects of CLA obtained in our study and other reports may be attributable to differences in metabolic rate, administered dose of dietary CLA, relative proportion of each isomer in a dietary CLA mixture, or length of the feeding period, as suggested by Terpstra (2001).…”

“…In the present study, inclusion of dietary CLA at 2% significantly reduced feed intake as observed by Twibell et al (2000), Diez et al (2007) and Makol et al (2009), and reduced feed efficiency as in fish fed the 2% CLA diet observed by Choi et al (1999). In contrast, growth performance and feed utilization were not affected by dietary CLA inclusion in several fish species (Twibell and Wilson, 2003;Berge et al, 2004;Kennedy et al, 2005;Bandarra et al, 2006;Ramos et al, 2008;Makol et al, 2009). In addition, Twibell et al (2000) reported that fish fed diets with CLA inclusion exhibited significantly improved feed efficiency compared to control animals.…”

“…Dietary CLA could be beneficial to fish culture if these effects on body composition and lipid metabolism could be reproduced in farmed fish without negative effects on growth performance. In fish, studies have shown that dietary CLA may alter growth responses, feed efficiency and lipid concentration (Twibell et al, 2000(Twibell et al, , 2001Yasmin and Takeuchi, 2002;Twibell and Wilson, 2003), and result in high CLA deposition levels (Twibell et al, 2000(Twibell et al, , 2001Berge et al, 2004;Kennedy et al, 2005;Bandarra et al, 2006;Valente et al, 2007a). Fish being an important source of protein and n−3 PUFA, and a further increase in its CLA content could be of great interest to enhance the nutritional value of cultured fish for human consumption.…”

Incorporation of conjugated linoleic and alpha linolenic fatty acids into Pimedolus maculatus fillets

“…Increased lipid content in diets is very attractive to the farming industry because lipids are a good energy source, which leads to greater protein sparing, improvements in feed conversion, and a decrease in the amount of waste produced by fish (GHANAWI et al, 2011;KENNEDY et al, 2005;MANNING et al, 2006;RAMOS et al, 2008). However, such an increase can lead to changes in body composition and slaughter quality, which lead to a negative impact regarding the overall market quality of fish due to an excessive deposition of fat in tissues such as the abdomen, liver and muscles (BANDARRA et al, 2006;KENNEDY et al, 2007;MANNING et al, 2006;RAMOS et al, 2008).…”