Growth performance, histological alterations and fatty acid profile in muscle and liver of sharp snout sea bream (Diplodus puntazzo) with partial replacement of fish oil by pork fat

Four isonitrogenous (42% crude protein) and isolipidic (20%) diets were formulated using four different percentages of pork fat to substitute fish oil at 0, 25, 50 and 75% to evaluate the performance, body composition, fatty acids and liver histology of sharpsnout sea bream juveniles. One hundred and twenty fish (average weight 33.4 ± 2.9 g) were randomly distributed into pens (90 l capacity). Triplicate groups were fed each test diet twice a day to apparent satiation for 84 days. No difference was observed for feeding and growth performance. The only significant difference with respect to carcass was in moisture content (P < 0.05). With respect to liver fatty acids, there were significant differences in EPA and DHA, being fish fed 75% of pork fat that obtained the lowest value. With respect to muscle fatty acids, there were significant differences in saturated fatty acids and fish fed 0% of pork fat obtained the lowest value, but in poly unsaturated fatty acids the 75% of pork fat reported the lowest value. Although in both fish muscle and liver fatty acids, fish fed 75% pork fat diet presented significant difference in n-3 highly unsaturated fatty acids and n3/n6, but in LA fish fed the 0% of pork fat diet presented the lowest value in liver and in fish muscle not only the 0% but also the 25% of pork fat diet obtained the lowest value.