凡纳滨对虾饲料中酵母水解物替代鱼粉适宜比例的研究

试验添加酵母水解物替代不同比例鱼粉, 添加量分别为0(对照组)、2.5%、5.0%、7.5%、10%和12.5%,替代鱼粉的比例分别为0、8%、16%、24%、32%和40%, 通过评估生长性能、消化酶和免疫相关酶活性等指标评价酵母水解物替代鱼粉对凡纳滨对虾健康生长的影响。选择健康凡纳滨对虾初重(0.630.01) g]随机分为6组, 每组3个重复, 养殖8周。结果表明, Y2.5和Y5.0处理组对虾增重率和特定生长率与Y0相比差异不显著(P0.05), 但是显著高于其余各组(P0.05), Y2.5组饲料系数和Y0组相比差异不显著, 显著低于其余各组(P0.05); Y5.0组肝胰腺糜蛋白酶和Y0组相比差异不显著(P0.05), 显著高于其余各组(P0.05); Y2.5和Y7.5组胰蛋白酶和Y0组相比差异不显著, 但是显著高于其余各组(P0.05); Y2.5组与Y5.0酚氧化酶活性显著高于其余各组(P0.05), Y2.5组与Y7.5组和Y0组总一氧化氮合酶活性显著高于其余各组(P0.05), Y5.0组和Y7.5组血清溶菌酶活性显著高于其余各组(P0.05)。以增重率为判据, 经二次曲线拟合得出, 获得最大增重率时酵母水解物添加量为1.62%, 替代鱼粉比例为5.19%; 酵母水解物替代鱼粉比例达24%时不会对增重率产生显著影响。

STUDY ON SUITABLE PROPORTION OF YEAST HYDROLYZATE REPLACEMENT OF FISHMEAL IN FEED OF LITOPENAEUSVANNAMEI

A series of 8 weeks feeding experiment was conducted to estimate the suitable proportion of yeast hydroly-zate (YH) suitable for fishmeal in feed of Litopenaeus vannamei. Supplementation of YH were 0, 2.5%, 5.0%, 7.5%, 10%and 12.5%, respectively. The substitution proportions for fishmeal were 0, 8%, 16%, 24%, 32%and 40%, respec-tively. The effects of yeast hydrolyzate instead of part fishmeal on the healthy growth of juvenile shrimp were evalu-ated by assessing the growth performance, digestive enzymes and immune enzymes activities. Each diet was fed to triplicate groups with shrimp initial body weight of (0.63±0.01) g] in a fresh water rearing system. The weight gain rate and specific growth rate of shrimps of Y2.5 and Y5.0 treatments showed no significant differences with the shrimp of Y0 treatment (P>0.05), which were significantly higher than that of the other treatments (P<0.05). No differences were found between the Y2.5 treatment and Y0 treatment in feed coefficient (P>0.05). Feed coefficient of Y2.5 treat-ment was lower than that of the other substitution treatments (P<0.05). Chymotrypsin activities of hepatopancreas in treatments Y5.0 and Y0 were not significant (P>0.05), but significantly higher than that of the rest treatments (P<0.05). Trypsin activities of hepatopancreas in treatments Y2.5, Y7.5 and Y0 were not significant (P>0.05), but significantly higher than that of the rest treatments (P<0.05). Polyphenol oxidase activities of shrimp of Y2.5 and Y5.0 were higher than the others (P<0.05). Total nitric oxide synthase activities of shrimp of Y0, Y2.5 and Y7.5 were higher than that of the others (P<0.05). Serum lysozyme activities of shrimp of Y5.0 and Y7.5 treatment were higher than that of the other treatments (P<0.05). Quadratic regression analysis of weight gain against YH replacement ratio of fishmeal indicated that the optimum additive amount was 1.62%and replacement ratio was 5.19%for the maximum weight gain of juve-nile shrimp. There was no difference on weight gain of shrimp while the replacement ratio of hydrolyzed yeast to fish-meal to 24%.