应用Cornell方法对重口裂腹鱼[Schizothorax(Racoma)davidi]幼鱼适宜常量营养物质需求量研究

CORNELL DESIGN APPLIED ON OPTIMAL MACRONUTRIENT COMPOSITION OF FORMULATED DIETS FOR DAVID’S SCHIZOTHORACIN [SCHIZOTHORAX (RACOMA) DAVIDI] JUVENILES

采用Cornell方法研究了初始重为(2.0±0.1)g的重口裂腹鱼幼鱼日粮中常量营养物质的适宜需求量。日粮中蛋白质、脂肪和碳水化合物梯度变化范围分别为33%—51%、3%—18%和24%—33%,试验周期为60d。试验结果表明,除日粮蛋白质33%组鱼成活率明显下降外(P<0.05),其它试验日粮中3种常量营养物质含量对重口裂腹鱼幼鱼成活率没有显著影响(P>0.05)。当日粮蛋白质水平≤45%时,其特定生长率随着日粮蛋白质水平上升而明显增加;当日粮蛋白质水平在33%—36%时,重口裂腹鱼的特定生长率显著降低(P<0.05)。除12%日粮脂肪组试验鱼外,9%日粮脂肪组试验鱼的特定生长率显著性高于其它脂肪水平日粮组(P<0.05),但当日粮中脂肪含量≥15%后,重口裂腹鱼鱼体脂肪含量显著上升(P<0.05),肝细胞脂肪变性明显。日粮中不同的碳水化合物水平对重口裂腹鱼特定生长率没有显著影响(P>0.05),但当日粮中碳水化合物为33%时,鱼体糖原含量显著增加(P<0.05)。试验表明,重口裂腹鱼幼鱼日粮蛋白质、脂肪和碳水化合物3种常量营养物质的适宜需求量分别为45%、9%和≤30%。日粮总能为19.0MJ/kg,蛋白质能量比(P/E)为23mg/J。

Cornell Design was used to investigate the optimal composition of macronutrients for David＇s schizothoracin [Schizothorax （Racoma） davidi] juveniles [（2.0±0.1）g initial weight. Protein, lipid and carbohydrate were varied between 33%--51%, 3%--18% and 24%--33% dry wt., respectively. The experiment lasted for 60 days. The test results showed that the dietary macronutrient composition was not reflected in the survival rate of the fish significantly except for signifi- cant decline at 33% dietary protein （P〈0.05）. There was a positive effect of increasing dietary protein levels up until 42% on the growth, while 33%--39% dietary protein resulted in growth depression significantly （P〈0.05）. Beside 12% dietary lipid, the fish at 9% dietary lipid showed significantly better growth than other dietary lipid levels （P〈0.05）. The lipid contents in fish body increased significantly （P〉0.05）, and fatty degeneration in hepatocytes was obvious as dietary lipid level was 〉/15%. The dietary carbohydrate composition was not reflected in the growth of the fish significantly （P〉0.05）, but 32% dietary carbohydrate level strongly increased accumulation of carbohydrate in whole baby of the fish （P〈0.05）. It could be concluded that the optimal protein requirement appears to be 42%, based on the limits of 9% for lipids and ≤ 30% for carbohydrate in the diets, while the dietary gross energy （GE） and protein energy rate （P/E） are 19.0MJ/kg and 23mg/kJ for David＇s Schizothoracin juveniles.