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 ( SREBP 1) 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.