Effects of substitution of fish meal by fermented soybean meal on growth and serum biochemistry of golden pompano (Trachinotus ovatus)

To investigate the effects of substitution of fish meal by fermented soybean meal on the growth performance and serum biochemistry of Trachinotus ovatus, we have formulated five experimental diets, adding 0% (FM), 25% (FSM25), 50% (FSM50), 75% (FSM75) and 100% (FSM100) fermented soybean meal to replace fish meal. In order to eliminate the effects of limiting amino acids, we added 0%, 0.10%, 0.22%, 0.35% and 0.45% lysine, as well as 0%, 0.14%, 0.27%, 0.41% and 0.54% methionine, respectively. The results show that the weight again rate, specific gain rate, specific growth rate and feed intake did not have significant difference among FSM25, FSM50 and FM groups (P>0.05), but the feed conversion ratio in FSM100 group was significantly higher than that in FM group (P<0.05). There was insignificant difference in the muscle moisture, ash, crude protein, crude fat contents between the fermented soybean meal groups and FM group (P>0.05). The serum aspartate aminotransferase (AST) activities and total protein (TP) contents in FSM75 and FSM100 groups were significantly higher and lower than those in FM group, respectively (P<0.05). The activities of alanine aminotransferase (ALT) and superoxide dismutase (SOD) in FM100 group were significantly higher than those in FM group, respectively (P<0.05). The relative expressions of IGF-1 and GH genes in FSM75 and FSM100 groups were significantly lower than those in FM group (P<0.05). In summary, by adding limiting amino acids, the substitution of fish meal by fermented soybean meal not exceeding 50% does not have adverse affects on T. ovatus. According to the regression curve, the substitution level of 17.5% will achieve the best effects.