草鱼幼鱼的饲料苏氨酸需要量  

Determination of dietary threonine requirement for juvenile grass carp, Ctenopharyngodon idella

作　　者：文华[1] 高文[2] 罗莉[2] 尚晓迪[2] 何宋伟[2] 钟利桥[2] 李飞[2] 

机构地区：[1]中国水产科学研究院淡水生态与健康养殖重点开放实验室,长江水产研究所,湖北荆州434000 [2]西南大学动物科技学院水产系,重庆400716

出　　处：《中国水产科学》2009年第2期238-247,共10页Journal of Fishery Sciences of China

基　　金：国家"十一五"科技支撑计划项目(2006BAD03B03)

摘　　要：选用初始体质量为(8.35±0.06)g的草鱼(Ctenopharyngodon idella)540尾,随机分成6组,每组3个重复,每个重复30尾鱼,分别饲喂苏氨酸水平为0.72%、1.02%、1.32%、1.62%、1.92%和2.22%(占饲料的质量分数)的6组等氮半精制饲料(蛋白质质量分数35%),经60d生长实验确定草鱼幼鱼的苏氨酸需要量。实验结果表明,随着饲料苏氨酸水平增加,草鱼的增重率、特定生长率、蛋白质效率、蛋白质沉积率、肌肉RNA/DNA比值和血氨水平显著升高(P<0.05),均在1.62%组达到最大值;饲料系数和肝脏谷氨酸脱氢酶活力显著降低(P<0.05),均在1.62%组达到最小值;随着饲料苏氨酸水平进一步提高,上述指标不再发生显著变化(P>0.05)。随饲料中苏氨酸水平的增加,草鱼血清总蛋白浓度显著升高,1.32%、1.62%和1.92%3组显著高于0.72%和1.02%组(P<0.05),2.22%组达最大值,并显著高于其他各组(P<0.05);血清甘油三酯和胆固醇浓度在饲料苏氨酸水平为1.32%～2.22%的4组间没有显著差异(P>0.05),但显著高于0.72%组和1.02%组(P<0.05)。饲料中苏氨酸水平为1.62%时,草鱼肌肉苏氨酸含量和肌肉氨基酸总量均为最大值,显著高于其他各组(P<0.05)。饲料苏氨酸适宜水平能使草鱼全鱼水分显著降低,增加蛋白质、脂肪和灰分含量(P<0.05),同时降低草鱼肌肉水分,增加蛋白质含量(P<0.05),但不影响脂肪含量(P>0.05)。饲料中苏氨酸水平对草鱼肝脏谷丙转氨酶、谷草转氨酶活力无显著影响(P>0.05)。以特定生长率、饲料系数、蛋白质沉积率、肌肉RNA/DNA和谷氨酸脱氢酶活力分别对饲料苏氨酸水平进行折线回归分析,并以这些指标达95%最佳值时为判断依据,得出草鱼幼鱼饲料中苏氨酸适宜需要量以占饲料的质量分数计为1.42%～1.61%(饲料蛋白质质量分数35%)或以占饲料蛋白质的质量分数为4.07%～4.60%。This experiment was conducted to determine the dietary threonine requirement for juvenile grass carp （Ctenopharyngodon idella）by formulating six isonitrogenous diets（35%protein）containing threonine increasing levels of 0.72%,1.02%,1.32%,1.62%,1.92%and 2.22%,respctively.Casein-gelatin-zein meal and crystalline amino acid mixture were used as dietary protein source.The dietary amino acid pattern,except for threonine,was applied to the amino acid pattern of the whole body protein of juvenile grass carp.Each experimental diet was fed to triplicate groups of 30 juvenile grass carp with initial body weight（8.35±0.06）g in freshwater floating net cages（1.0 m×1.0 m×1.0 m） for 60 d.The result showed that with the increase of dietary threonine levels,the weight gains（WG）,specific growth rates（SGR）,protein efficiency ratios（PER）,protein retention efficiencies（PRE）,RNA/DNA ratios in muscle,and blood ammonia contents of the fish increased significantly（P〈0.05）,which reached their peaks in the 1.62%group, whereas the feed conversion ratios（FCR）and glutamate dehydrogenase（GDH）activities in liver decreased significantly （P〈0.05）,which reached the lowest values in the same group,and all of these indices became stable thereafter（P〉0.05）. Serum total protein increased significantly with the increase of dietary threonine levels（P〈0.05）,with those of the three groups fed the diets supplemented with 1.32%,1.62%,and 1.92%dietary threonine significantly higher than the groups fed the diets supplemented with 0.72%and 1.02%dietary threonine（P〈0.05）,and serum total protein of the group fed the diet with 2.22%dietary threonine was significantly higher than those fed other diets（P〈0.05）.Serum triglyceride and cholesterol contents of the four groups fed the diets with 1.32%-2.22%dietary threonine were significantly higher than those fed the diets with 0.72%and 1.02%dietary threonine（P〈0.05）,but among the formers,no significant difference was found（P〉0.05�

关 键 词：草鱼 幼鱼 苏氨酸需要量 

分 类 号：S96[农业科学—水产养殖]