Effects of fishmeal replacement with eight protein sources on growth performance, blood biochemistry and stress resistance in Opsariichthys bidens

Nine experimental diets were formulated to study the effects of fishmeal replacement on Opsariichthys bidens. Weight gain rate, protein efficiency rate and apparent digestibility coefficient of fish in fishmeal (FM), maggot meal (MM) and soybean meal (SM) groups were significantly the highest. There was no significant difference in intestinal amylase activity between FM and SM groups. Principal component analysis showed that SM group and wild fish (WF) individual had similar essential amino acid compositions in muscle. The lowest value of serum malondialdehyde and the highest value of total antioxidant capacity were found in SM group, but fish in MM group did the opposite. Fish in MM group had the higher whole-body lipid, serum triglycerides, glucose, complement C3, C4 and immunoglobulin contents and lysozyme activity. After ammonia exposure, cumulative mortality of fish in FM and SM groups was significantly the lowest. Liver carbamyl phosphate synthetase activity of fish in FM group was significantly the highest, but the highest values of glutamine synthetase and glutamate dehydrogenase were found in SM group. This study suggests that fishmeal replacement with soybean meal is acceptable, and muscle amino acid compositions of fish in SM group were more similar to wild individual.