益生菌对军曹鱼幼鱼生长性能、消化酶和免疫酶活性的影响

摘要

This experiment was conducted to study the effects of Bacillus subtilis and Lactobacillus acidophilus as separate or mixed in diets on the growth performance, digestive enzyme and immune enzyme activities of ju-venile cobia ( Rachycentron canadum ) . Eight hundred and forty healthy juvenile cobia with an initial body weight of (22.00±0.15) g were randomly divided into 7 groups (groups T0, T1, T2, T3, T4, T5 and T6, respectively) with 3 replicates per group and 40 fish per replicate. The group T0 was used as control group, and fish in this group were fed a basal diet for 50 days;the fish in groups T1, T2 and T3 were fed diets contai-ning 1×107 CFU/g B. subtilis, 1×107 CFU/g L. acidophilus and 2×107 CFU/g B. subtilis and L. acidophilus mixture ( mass ratio of B. subtilis and L. acidophilus=1:1) for 30 days and then 20 days switched to basal di-et, respectively; the fish in groups T4, T5 and T6 were fed diets containing 1 × 107 CFU/g B. subtilis, 1 × 107 CFU/g L. acidophilus and 2×107 CFU/g B. subtilis and L. acidophilus mixture for 50 days, respectively. The results showed as follows: compared with control group, the weight gain rate ( WGR) in groups T1 and T2 had no significant difference ( P>0.05) , but the WGR in groups T3, T4, T5 and T6 was significantly in-creased ( P<0.05) , and the group T6 had the maximum value which was significantly higher than that in other groups ( P<0.05) . The specific gain rate ( SGR) had a similar changing trend to WGR. The feed conversion ratio ( FCR) in groups T2, T3, T4, T5 and T6 was significantly lower than that in control group ( P<0.05) , meanwhile, the FCR in groups T4 and T6 was significantly lower than that in other probiotics supplemental groups ( P<0.05) . Diets with supplementation of probiotics could significantly enhance the activities of amylase and protease in liver (P<0.05), and improve the activity of protease in intestine (P<0.05). The activity of amylase in intestine in control goup, groups T3 and T4 was significantly lower than that in groups T5 and T6,and significantly higher than that in groups T1 and T2 ( P<0. 05 ) . Diet with supplementation of probiotics could significantly improve the activity of serum lysozyme ( LZM) ( P<0.05) . The serum total superoxide dis-mutase ( T-SOD) activity in continuous feeding groups ( groups T4, T5 and T6) was significantly higher than that in control group ( P<0.05) , and the serum T-SOD activity in group T6 was significantly higher than that in groups T4 and T5 ( P<0. 05 ) . However, the serum T-SOD activity in non-continuous feeding groups ( groups T1, T2 and T3) was significantly lower than that in control group except group T1 ( P<0.05) . Com-pared with the control group, the serum alkaline phosphatase ( AKP) activity in probiotics supplemental groups was significantly decreased ( P<0.05) . The serum acid phosphatase ( ACP) activity in groups T2 and T3 was significantly higher than that in control group ( P<0.05) , and group T6 had no significant difference with con-trol group ( P>0.05) , while that in other groups was significantly lower than that in control group ( P<0.05) . These results indicate that supplementation of B. subtilis and L. acidophilus as separate or mixed (1:1, mass ra-tio) in diets can promote the growth, and increase the activities of immune enzymes and digestive enzymes of juvenile cobia. Continuous feeding is better than non-continuous feeding and the mixed probiotics has the best effect.%本试验旨在研究枯草芽孢杆菌、嗜酸乳杆菌单独或混合添加于饲料中对军曹鱼幼鱼生长性能、消化酶和免疫酶活性的影响. 选取平均体重为(22.00±0.15) g的健康军曹鱼幼鱼840尾,随机分成7组( T0、T1、T2、T3、T4、T5、T6组) ,每组3个重复,每个重复40尾鱼. T0组为对照组,投喂基础饲料50 d;T1、T2和T3组前30天分别投喂含1×107 CFU/g枯草芽孢杆菌、1× 107 CFU/g嗜酸乳杆菌、2×107 CFU/g枯草芽孢杆菌与嗜酸乳杆菌混合物(枯草芽孢杆菌:嗜酸乳杆菌=1:1,质量比)的饲料,后20天投喂基础饲料;T4、T5和T6组分别投喂含1×107 CFU/g枯草芽孢杆菌、1×107 CFU/g嗜酸乳杆菌、2×107 CFU/g枯草芽孢杆菌与嗜酸乳杆菌混合物的饲料50 d. 结果显示:与对照组相比,T1、T2组的增重率(WGR)无显著差异(P>0.05),T3、T4、T5、T6组的WGR则显著升高( P<0.05) ,最大值出现在T6组,且显著高于其他各组( P<0.05).特定生长率( SGR)的变化趋势与WGR类似. T2、T3、T4、T5、T6组的饲料系数( FCR)显著低于对照组(P<0.05),同时T4和T6组还显著低于其他益生菌添加组(P<0.05). 饲料中添加益生菌能显著提高肝脏淀粉酶及肝脏和肠道蛋白酶活性( P<0.05);对照组及T3和T4组肠道淀粉酶活性显著低于T5和T6组( P<0.05) ,显著高于T1和T2组( P<0.05). 各益生菌添加组血清溶菌酶活性均显著高于对照组( P<0.05). 持续投喂益生菌组( T4、T5、T6组)血清总超氧化物歧化酶活性显著高于对照组( P<0.05) ,且T6组还显著高于T4和T5组( P<0.05) ,非持续投喂益生菌组(T1、T2、T3组)中除T1组外均显著低于对照组(P<0.05). 与对照组相比,饲料中添加益生菌显著降低血清碱性磷酸酶活性( P<0.05);血清酸性磷酸酶活性除T2和T3组显著高于对照组(P<0.05)、T6与对照组无显著差异(P>0.05)外,其余各组均显著低于对照组(P<0.05). 本试验条件下,饲料中添加枯草芽孢杆菌、嗜酸乳杆菌或二者的混合物(质量比1:1)均能够促进军曹鱼幼鱼的生长,提高免疫酶和消化酶活性,持续投喂效果优于非持续投喂,以持续投喂2种益生菌混合物的效果最佳.