活性和热灭活原籍嗜冷杆菌SE6对斜带石斑鱼幼鱼生长性能和免疫功能的影响

摘要

为探讨灭活益生菌在海水鱼养殖中的应用前景,研究了饲料中添加活性和热灭活原籍嗜冷杆菌SE6对斜带石斑鱼幼鱼生长性能和血清免疫指标的影响.225尾斜带石斑鱼幼鱼[(14.6±0.2)g]被随机分成3组,每组3个重复.对照组T0投喂基础饲料,实验组T1和T2分别投喂添加1.0×108 cfu/g活性和热灭活嗜冷杆菌SE6的基础饲料,饲喂期为60 d.结果表明,实验前期(0～30 d),实验组T1和T2特定生长率和增重率均显著高于对照组(P＜0.05),饵料系数均低于对照组,但差异不显著(P＞0.05)；实验全期(0 ～60 d),实验组T1和T2特定生长率和增重率均显著高于对照组(P＜0.05),实验组饵料系数均下降,其中实验组T1显著低于对照组T0(P ＜0.05).实验30 d时,实验组T1和T2血清IgM和补体C3含量均高于对照组,但差异不显著(P＞0.05)；60 d时,实验组T1的补体C3水平、总超氧化物歧化酶活力和IgM含量均显著高于对照组T0(P＜0.05),实验组T2的补体C3水平、T-SOD活力、IgM含量和溶菌酶活力也高于对照组,但差异不显著(P＞0.05).总之,活性和热灭活嗜冷杆菌均可不同程度地促进石斑鱼生长,降低饵料系数,并能提高石斑鱼特异性和非特异性免疫功能.热灭活嗜冷杆菌的应用效果略低于活性菌,但其具有安全性高、质量稳定、生产储藏容易等优势,在海水鱼养殖中的应用值得深入研究.%To illustrate the application prospect of nonviable probiotics in marine fish aquaculture, the present study evaluated the effect of dietary administration of viable and heat-inactivated autochthonous probiotic Psychrobacter sp. SE6 on the growth performance and serum immune parameters of grouper (Epinephelus coioides).225 juvenile fish with an initial weight of(14. 6 ±0. 2)g were randomly divided into 3 groups (groups TO ,T1 and T2) with 3 replicates per group and 25 fish per replicate. The fish were fed for 60 d with basal diet containing 0 cfu/g(control group T0), 1 × 108 cfu/g viable Psychrobacter sp. SE6( group T1) and 1 × 108 cfu/g heat-inactivated Psychrobacter sp. SE6 (group T2), respectively. The results showed that, in the early period (0 -30 d) ,the weight gain rate (WGR) and specific growth ratio (SGR) of the two probiotic groups were significantly higher than the control group(P <0.05) ,and the feed conversion ratios (FCR) of two probiotic groups were lower than those of the control group. During the whole experimental period(0 -60 d), the WGR and SGR of the two experimental groups were significantly higher than those of the control group (P < 0.05), the FCR of the two experimental groups was lower than that of the control group, and the FCR of group T1 was significantly lower than that of the control ( P < 0. 05 ). At day 30, the serum immunoglobulin M (IgM) and complement C3 contents in the experimental groups were higher than the control group,but not significantly ( P > 0.05). At day 60, the serum T-SOD activity, complement C3 and IgM contents in the group Tl were significantly higher than those of the control (P < 0. 05), while the activities of T-SOD and lysozyme, complement C3 and IgM contents in the group T2 were higher than those of the control, but not significantly ( P >0.05). In conclusion, both the viable and heat-inactivated Psychrobacter sp. SE6 played positive roles in promoting the growth performance and feed utilization, improving specific and nonspecific immune functions in E. coioides. Although better effect was observed in the viable probiotic group, the heat-inactivited probiotics have several advantages, such as high safety, stable quality and convenient processing and storage. Therefore, further study is needed to evaluate the application of heat-inactivated probiotcs in marine fish aquaculture.