microcapsule methionine or crystalline methionine in low-fishmeal diets on protein metabolism and digestive enzyme activities in cobia (). Seven iso-nitrogen and iso-lipid diets, including fishmeal (positive control), low-fishmeal (negative control) and five types of methionine supplementation of crystalline L-methionine(MET), hydroxyl-methionine calcium(MHA), cellolose-acetate-phthalate coated methionine coated methionine(TPA), respectively were prepared to investigate utilization of coated and crystalline methionine in intestine of juvenile cobia. Each treatment was randomly assigned to triplicate groups of 20 fish with initial weight of (5.40±0.07) g per aquarium. Fish were maintained in flow- through aquaria The results showed that trypsin activities of intestine of fish fed microcapsule methionine were significantly higher than those of fish fed crystalline methionine and the positive control diet(<0.05). Compared to positive and negative groups, fish fed the diets with MET and TPA had significant difference in liver GOT activities (-ATP activities in intestine of fish fed MET were significantly higher than those of fish in other groups (-ATP activities of fish fed RES and positive control diet increased and was higher than those of fish fed CAP and MHA, and those activities of fish fed positive control diets and microcapsule methionine were significantly higher than those of fish fed MHA and MET after feeding 8 h (<0.05). It could be concluded that cobia fed low fishmeal diet with crystalline methionine could improve their metabolism of amino acid and synthesis of protein. M methioninethe of intestinal protease.