Effects of fish oil replacement by a vegetable oil blend on digestibility, postprandial serum metabolite profile, lipid and glucose metabolism of European sea bass (Dicentrarchus labrax) juveniles
Résumé
A digestibility trial was conducted to evaluate the effects of dietary fish oil (FO) replacement by a vegetable oil blend
(VO) (rapeseed, linseed and palm oils) on nutrient digestibility, lipid absorption and transport and lipid and carbohydrate
metabolic pathways of Dicentrarchus labrax juveniles. Following 36 days, the liver and intestine of fish were sampled 6 h after the last meal. Remaining fish were fed one more week and blood was collected at different postprandial time intervals. Dietary VO decreased apparent digestibility coefficients (ADC) of lipid and energy. Among the serum parameters analysed, only high-density lipoprotein was affected, being higher in VO group. Hepatic and intestinal expression of genes related to lipid transport and lipoprotein metabolism (FABP, DGAT, ApoB, ApoA4, ApoA1, MTP) showed no differences in transcript levels No alteration in genes related to cholesterol biosynthesis (HMGCR), glucose transport (GLUT2) or metabolism (GK, PK, G6Pase and PEPCK) in the liver and intestine was found. However, hepatic transcript levels of FADS2
and elovl5 were up-regulated in VO group. In conclusion, replacement of FO by VO did not induce major alterations at molecular and biochemical levels, although a nutritional modulation of LC-polyunsaturated fatty acids biosynthesis
pathway was observed