菜粕、棉粕替代豆粕对奥尼罗非鱼(Oreochromis niloticus×O.aureus)生长、体组成和免疫力的影响

在一种实用饲料配方(粗蛋白28%,豆粕18%)的基础上,用菜粕、棉粕按1∶2的比例等量替代豆粕(6%、12%、18%)作为蛋白源配制成三种等能等氮的无鱼粉饲料,在室内饲养奥尼罗非鱼Oreochromis niloticus×O.aureus,平均体重为(4.22±0.09)g]8周。结果表明,菜粕、棉粕替代不同水平豆粕对罗非鱼的生长、饲料利用和机体免疫力均产生了显著的影响(P<0.05)。随菜粕、棉粕替代水平的增加,罗非鱼的生长、饲料利用和体蛋白含量均显著下降(P<0.05),而以无豆粕组影响最大。鱼体肝脂含量、肝体比(HSI)以及脏体比(VR)在组间差异不显著(P>0.05)。无豆粕组血清GPT、GOT酶活力显著升高(P<0.05),而血清SOD、LZ酶活力显著降低(P<0.05)。配方中棉粕和菜粕的总量超过52%对罗非鱼是不安全的。

EFFECT OF SOYBEAN MEAL REPLACEMENT BY RAPESEED-COTTONSEED COMPOUND ON GROWTH, BODY COMPOSITION AND IMMUNITY OF TILAPIA OREOCHROMIS NILOTICUS×O. AUREUS

Driven by market high pricing, low-priced feedstuff for aquiculture are sought and tested. This study evaluates the effect using less-expensive rapeseed-cottonseed combo feed mixed with formally used soybean meal (SBM, whose price has been rising in recent years) for juvenile tilapia Oreochromis niloticus ×O. aureus (4.22±0.09) g] in different combinations. Soybean-based (the control, Diet 1) and rapeseed-cottonseed combo (rapeseed: cottonseed = 1 : 2) were tested at equal nitrogen and caloric basis. The combinations include the replacement of soybean meal at 6% (Diet 2), 12% (Diet 3) and l8% (Diet 4) with the combo, respectively. The 4 experimental diets were formulated to contain 28% crude protein on an isocaloric basis. Each diet was randomly fed to triplicate tanks of the juvenile three times a day at 4%-8% of wet body weight for 8 weeks. The activities of glutamic-pyruvic transaminase (GPT), glutamic-oxalacetic transaminase (GOT), superoxide dismutase (SOD) and lysozyme (LZ) in serum were assayed at the end of the experiment. The results showed that the best performance in terms of specific growth rate (SGR), relative weight gain ratio (RWGR), feed conversion ratio (FCR) and protein efficiency ratio (PER) were shown by the Diets 3 and 4. The 4 parameters were affected significantly by soybean-free diet (P < 0.05). No significant differences were observed in dry matter, whole body moisture, protein, lipid and ash among 4 diet groups (P > 0.05). The relative weights of viscus and hepatopancreas, and liver fat did not change significantly (P < 0.05). GPT and GOT activities of the juvenile tilapia serum in no-soybean treatment are significantly higher than that of other 3 groups (P < 0.05). However, SOD and LZ activities in no-soybean groups are significantly lower than that of the other groups (P < 0.05). The results show that rapeseed-cottonseed combo may be included in the diet up to 52% as a substitute for SBM.