Effect of diets low in fish oil and supplemented with chlorogenic acid on fatty acid composition and lipid metabolism in Atlantic salmon (Salmo salar L.)

This study aimed to test the use of chlorogenic acid (CGA), a natural antioxidant, which might act improving the retention of eicosapentaenoic (EPA) and docosahexaenoic (DHA) fatty acids. Fish were fed one of three experimental diets. A diet with 160 g kg(-1) fish oil (FO) and 80 g kg(-1) vegetable oil (VO) was used as a positive control with high n-3 long-chain polyunsaturated fatty acids (LC)-PUFA, a diet containing 40 g kg(-1) FO and 200 g kg(-1) VO was used as a negative control for low n-3 LC-PUFA and 1 g kg(-1) CGA was added to the negative control diet to test the impact of CGA on n-3 LC-PUFA synthesis. The expression of genes involved in PUFA synthesis was upregulated in the liver of fish fed the low n-3 LC-PUFA diets. This might be due to the activation of sterol regulatory element-binding transcription factor 1 (SREBP1) and liver X receptor. Moreover, malondialdehyde concentration tended to decrease, and accumulation of dietary EPA in the liver in relation to diet was observed in fish fed the low n-3 LC-PUFA diets. However, the concentration of EPA and DHA was higher in fish fed the positive control diet. The inclusion of 1 g kg(-1) CGA did not exert any additional effect on lipid peroxidation, EPA and DHA concentrations or LC-PUFA metabolism.