酵母核苷酸对鲤生长性能、体组成及血清免疫指标的影响

Effects of Yeast Nucleotide on Growth Performance,Body Composition and Immune Indices of Common Carp (Cyprinus carpio)

本试验旨在研究酵母核苷酸对鲤生长性能、体组成及血清免疫指标的影响。以600尾健康的鲤[平均体重(1.09±0.07)g;平均体长(3.60±0.34)cm]为试验对象,随机分为6组(每组3个重复,每个重复30尾),分别投喂在基础饲料中添加0(对照组)、258、516、774、1032、1290mg/kg酵母核苷酸(以有效成分计)的试验饲料,养殖50d。结果表明:与对照组相比,各酵母核苷酸添加组的增重率(WGR)、特定生长率(SGR)、蛋白质效率(PER)(258mg/kg组除外)均显著升高(P<0.05),饵料系数(FCR)则显著降低(P<0.05)。当酵母核苷酸添加量为516mg/kg时,鲤的增重率、特定生长率、蛋白质效率均达到最大(分别为372.03%、3.10%/d和195.74%),饵料系数达到最低(1.42),与其他各组差异显著(P<0.05)。以增重率、特定生长率、蛋白质效率及饵料系数为指标,利用折线模型分析表明,鲤生长性能最佳时酵母核苷酸添加量为519.85～535.54mg/kg。对鲤体组成分析表明,酵母核苷酸对鱼体粗灰分和水分含量影响不显著(P>0.05),当酵母核苷酸添加量在516～1290mg/kg时鱼体粗蛋白质和粗脂肪含量显著高于对照组(P<0.05)。与对照组相比,各酵母核苷酸添加组的血清溶菌酶、超氧化歧化酶、过氧化氢酶活性显著升高(P<0.05),并随酵母核苷酸水平的增加先增加后降低。酵母核苷酸添加量为774～1290mg/kg时,血清溶菌酶、超氧化歧化酶活性较高;在酵母核苷酸添加量为516～1032mg/kg时,血清过氧化氢酶活性较高。综合考虑生长性能和免疫能力,鲤饲料中酵母核苷酸的适宜添加量为519.85～774.00mg/kg。

The experiment was conducted to study the effects of yeast nucleotide on growth performance, body composition and serum immune indices of common carp （Cyprinus carpio）. Six hundred healthy common carp [average body weight of （1.09±0.07） g and average body length of （3.60±0.34） cm] were randomly allotted to 6 groups and each group included 3 replicates with 30 fish. Fish in 6 groups were fed with basal diet supplemented with 0 （control group）, 258, 516, 774, 1 032, and 1 290 mg/kg yeast nucleotide （effective components）, respectively. The trial lasted for 50 days. The results showed as follows： compared with the control group, the weight gain ratio （WGR）, specific growth ratio （SGR） and protein efficiency ratio （PER） of yeast nucleotide supplementation groups were significantly increased （P0.05）, at the same time, the feed conversion ratio （FCR）of yeast nucleotide supplementation groups was significantly decreased （P0.05）. The highest WGR, SGR and PER （372.03%, 3.10%/d and 195.74%, respectively） and the lowest FCR （1.42） of fish were found in 516 mg/kg group, and the differences were significant between 516 mg/kg group and the other groups （P0.05）. Based on broken-line model analysis of the WGR, SGR, PER and FCR, the optimal dietary yeast nucleotide supplemental levels for this formulation were 519.85 to 535.54 mg/kg. Body composition analysis showed that the crude ash and moisture contents in whole body were not affected by the supplementation of yeast nucleotide （P0.05）, but the crude protein and crude lipid contents were significantly higher with the increase of dietary yeast nucleotide supplemental level （516 to 1 290 mg/kg） than the control diet （P0.05）. Compared with the control group, the activities of serum lysozyme （LSZ）, superoxide dismutase （SOD） and catalase （CAT） of yeast nucleotide supplementation groups were significantly increased （P0.05）, and the activities of these enzymes were increased first and decreased afterwards with the dietary yeast nucleotide supplemental level increasing. Fish had higher activities of serum LSZ and SOD when the dietary yeast nucleotide supplemental levels were 774 to 1 290 mg/kg, at the same time, the fish had a higher serum CAT activity when fed 516 to 1 032 mg/kg yeast nucleotide supplemental diets. Based on the above information, the optimal dietary yeast nucleotide supplemental levels in common carp diets for optimum growth performance and immune ability are 519.85 to 774.00 mg/kg.