草鱼幼鱼对缬氨酸需要量的研究(英文)

Research on Dietary Valine Requirement of Juvenile Grass Carp (Ctenopharyngodon idella)

试验选用体重(9.5±0.3)g的草鱼幼鱼,随机分成6个组,每组3个重复,每个重复20尾;以花生仁粕、酪蛋白及明胶为蛋白质源,分别饲喂缬氨酸水平为7.3～22.3g/kg的6组等氮半精制饲料(粗蛋白质含量为32%),经70d的生长试验研究其日粮缬氨酸的最适需求量。试验结果表明:日粮缬氨酸水平对草幼鱼的增重率、特定生长率、蛋白质效率、肌肉RNA/DNA比率、鱼体常规成分组成、消化酶活性、肝胰脏谷草-谷丙转氨酶和谷氨酸脱氢酶活性以及血液学指标都有显著的影响(P<0.05)。随日粮缬氨酸水平的增加,增重率、特定生长率、蛋白质效率及肌肉RNA/DNA比率均呈先升后降趋势,均在16.3g/kg组达到最大值(P<0.05)。以增重率、特定生长率、肌肉RNA/DNA比率为基础对饲料缬氨酸水平进行二次回归分析,确定草鱼幼鱼日粮(32%粗蛋白质)缬氨酸适宜需要量分别为15.6、15.1及16.0g/kg(日粮基础)或48.8、47.2及50.0g/kg(日粮蛋白质基础)。

A 70-day feeding trial was conducted to estimate the optimum requirement of dietary valine for juvenile grass carp using six isonitrogenous diets （32% protein） with peanut meal,casein,and gelatin as protein resource supplemented with six graded levels of coated valine （from 7.3 to 22.3 g/kg of dry diet）. Each diet was randomly assigned to three replicates of 20 fish each with average weight of （9.5±0.3） g. The results showed that weight gain ratio （WGR）,specific growth rate （SGR）,protein efficiency ratio （PER）,body composition,RNA/DNA ratio in muscle,digestive enzyme activity,alanine amino transferase （ALT） and aspartate amino transferase （AST） and glutamate dehydrogenase （GDH） activity in hepatopancreas and hematology were all significantly （P0.05） affected by the dietary valine levels. WGR,SGR,PER and RNA/DNA ratio in muscle were significantly increased with valine level increasing from 7.3 to 16.3 g/kg of diet （P0.05）,and then decreased. Second-degree polynomial regression analysis for WGR,PER and RNA/DNA ratio in muscle indicated that the optimum requirements of dietary valine of juvenile grass carp were 15.6,15.1 and 16.0 g/kg of diet （48.8,47.2 and 50.0 g/kg of dietary protein）,respectively.