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 ...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.展开更多
筛选出10对扩增片段长度多态分析技术(Amplified fragment length polymorphism,AFLP)的选择性扩增引物(E-aga/M-cgt、E-aga/M-cga、E-agc/M-cga、E-agg/M-cga、E-act/M-cgc、E-aag/M-cgc、E-aca/M-cga、E-aac/M-cgc、E-aac/M-cac和E-aa...筛选出10对扩增片段长度多态分析技术(Amplified fragment length polymorphism,AFLP)的选择性扩增引物(E-aga/M-cgt、E-aga/M-cga、E-agc/M-cga、E-agg/M-cga、E-act/M-cgc、E-aag/M-cgc、E-aca/M-cga、E-aac/M-cgc、E-aac/M-cac和E-aac/M-cat),分析了4个军曹鱼(Rachycentron canadum)全人工繁育群体海南1(HN1)、海南2(HN2)、湛江(ZJ)和流沙湾(LS)的遗传结构。结果表明:总体多态位点比例(83.9%)、分化指数(0.427 8)和Shannon信息指数(0.614 9)均处于较高水平,遗传多样性丰富;主坐标分析和邻位连接树中LS-HN2支与ZJ-HN1支明显分离,各群体内多样性水平存在差异(遗传多样性大小依次为HN1、HN2、LS、ZJ),但总体基因流仍然较大(Nm=10.327),分子方差分析(AMOVA)获得的群内方差(53%)也略大于群间(47%)。展开更多
基金Supported by the Special Fund for Agro-Scientific Research in the Public Interest(No.201003020)the Pearl River Scholar Funded Scheme for Universities and Colleges in Guangdong Province(GDUPS,No.2011)the Natural Science Foundation of Guangdong Ocean University of China(No.1212345)
文摘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.
