We evaluated the effects of supplemental coated and crystalline methionine(Met) on the growth performance and feed utilization of juvenile cobia(Rachycentron canadum Linnaeus) in a 60-d feeding trial.Fish groups were fed one of six isonitrogenous and isolipidic diets:1) fishmeal control;2) unsupplemented experimental(low-fish-meal diet deficient in Met);or 3) one of four Met diets supplemented with crystalline L-Met,cellulose-acetate-phthalate coated L-Met,acrylic-resin coated L-Met,or tripalmitinpolyvinyl alcohol coated L-Met.The test diets were fed to triplicate groups of cobia(initial body weight5.40+0.07 g) twice a day.The weight gain and specific growth rate of the fish fed the RES diet were highest among the Met-supplemented groups and were 23.64%and 7.99%,respectively,higher than those of the fish fed with the un-supplemented experimental diet(P<0.05).The protein efficiency ratio of the fish fed the MET diet was significantly higher than that of the fish fed the un-supplemented experimental diet and the fish in the other methionine supplementation groups(P<0.05).Our results suggest that supplementation of crystalline Met in low-fish-meal diets promotes the growth performance of juvenile cobia. We evaluated the effects of supplemental coated and crystalline methionine (Met) on the growth performance and feed utilization of juvenile cobia (Rachycentron canadum Linnaeus) in a 60-d feeding trial. Fish groups were fed one of six isonitrogenous and isolipidic diets: 1) 2) unsupplemented experimental (low-fish-meal diet deficient in Met); or 3) one of four Met diets supplemented with crystalline L- Met, cellulose-acetate- phthalate coated L-Met, Met, or tripalmitinpolyvinyl alcohol coated L-Met.The test diets were fed to triplicate groups of cobia (initial body weight 5.40 + 0.07 g) twice a day. Weight gain and specific growth rate of the fish fed the RES dietrants highest Among the Met-supplemented groups and were 23.64% and 7.99%, respectively, higher than those of the fish fed with the un-supplemented experimental diet (P <0.05). than that of the fish fed the un-supplemented experimental diet and the fish in the other methionine supplementation groups (P <0.05) .Our results suggest that supplementation of crystalline Met in low-fish-meal diets promotes the growth performance of juvenile cobia.