Abstract:This study explored the effects of dietary palmitic acid/(docosahexaenoic acid [DHA] and eicosapentaenoic acid [EPA]) on the anti-oxidative capacity and muscle quality of large yellow croaker (initial weight: 30.51 ± 0.16 g). Fish meal and soybean meal were used as the main dietary protein sources. DHA rich oil, EPA-rich oil, palmitic acid, and lecithin were used as the main dietary lipid sources. Three isonitrogenous (43 % crude protein) and isolipidic (11 % crude lipid) experimental diets were formulated to have 1∶5, 1∶1, and 5∶1 palmitic acid/(EPA+DHA) ratios, and called P0, P50, and P100, respectively. The feeding trial lasted for 10 weeks. Results showed that there was no significant difference in the growth rate among the three groups (P>0.05). Compared with the P100 group, the hardness, adhesiveness, cohesiveness, and chewiness of muscle in large yellow croaker fed P0 and P50 were significantly higher (P<0.05). Muscle polyunsaturated fatty acid (PUFA) content in the P0 group was significantly higher than that in the P50 and P100 groups (P<0.05). The saturated fatty acid (SFA) content of the P100 group was significantly higher than that in the P0 and P50 groups (P<0.05). The expression levels of superoxide dismutase 2 gene (SOD2) and catalase gene (CAT) in the muscle of the P100 group were significantly higher than those in the P0 and P50 groups (P<0.05). The gene expression level of muscle nuclear factor E2-related factor 2 gene (Nrf2) in the P0 group was significantly higher than that in the P50 group (P<0.05); however, there was no significant difference either between the P100 and P0 groups or between the P100 and P50 groups (P>0.05). There was no significant difference among the three groups in the expression level of superoxide dismutase 1 gene (SOD1) in muscle (P>0.05). The total anti-oxidative capacity (T-AOC) of muscle in the large yellow croaker fed P50 was significantly lower than that in the P0 and P100 groups (P<0.05). The activities of total superoxide dismutase (T-SOD) and CAT, and malondialdehyde (MDA) content of muscle showed no significant differences among all the groups (P>0.05). In conclusion, higher antioxidative capacity was found in muscle when large yellow croaker juveniles were fed with higher levels of dietary palmitic acid or (EPA+DHA). Higher dietary palmitic acid levels decreased the texture parameters in muscle.
