饲料中添加β-葡聚糖对黄颡鱼幼鱼生长性能、血清生化指标及抗嗜水气单胞菌感染能力的影响

Effects of Dietary β-Glucan on Growth Performance,Serum Biochemical Indices and Resistance Against Aeromonas hydrophila of Juvenile Yellow Catfish( Pseudobagrus fulvidraco)

为研究饲料中添加β-葡聚糖对黄颡鱼幼鱼生长性能、血清生化指标及抗嗜水气单胞菌感染能力的影响,在基础饲料中分别添加200、600和1 000 mg/kgβ-葡聚糖配制3种试验饲料。选取初始体重为（1.53±0.04）g的健康黄颡鱼幼鱼720尾,随机分为7组,包括1个投喂基础饲料的对照组（G0组）、3个连续投喂添加β-葡聚糖饲料的连续投喂组（SG200、SG600、SG1000组）及3个间隔投喂添加β-葡聚糖饲料和基础饲料各7 d的间隔投喂组（IG200、IG600、IG1000组）。连续投喂组每组4个重复,对照组和间隔投喂组每组3个重复,每个重复均为30尾鱼。试验期为42 d。养殖试验结束后,注射嗜水气单胞菌进行感染试验,计算96 h内的累计死亡率。结果显示：1）7组黄颡鱼幼鱼的增重率、饲料系数、蛋白质效率和存活率均没有显著差异（P〉0.05）,但IG1000组的肝体比较对照组显著降低（P〈0.05）。各β-葡聚糖添加组的增重率和蛋白质效率与对照组相比均有所升高,且连续投喂组的增重率高于对应的间隔投喂组,并在SG600组达到最高。2）各β-葡聚糖添加组全鱼粗蛋白质、粗脂肪和粗灰分含量均高于对照组,同时水分含量均低于对照组,但组间差异不显著（P〉0.05）。3）饲料中添加β-葡聚糖对黄颡鱼幼鱼各血清生化指标均无显著影响（P〉0.05）;与对照组相比,SG1000和IG600组血清球蛋白和总蛋白含量有所升高,各β-葡聚糖添加组血清谷丙转氨酶和谷草转氨酶活性均有所降低。4）嗜水气单胞菌感染96 h后,各组的累计死亡率在35%～46%之间,组间差异不显著（P〉0.05）。由此得出,除间隔投喂1 000 mg/kgβ-葡聚糖显著降低肝体比外,不论采取连续投喂还是间隔投喂方式,饲料中添加200、600和1 000 mg/kgβ-葡聚糖对黄颡鱼幼鱼的生长性能、体成分、血清生化指标及抗嗜水气单胞菌感染能力均没有显著影响。

A 42 days feeding trial was conducted to study the effects of dietary β-glucan on growth performance,serum biochemical indices and resistance against Aeromonas hydrophila of juvenile yellowcatfish（ Pseudobagrus fulvidraco）. A basal diet was supplemented with 200,600 and 1 000 mg /kg β-glucan to prepare three test diets. Seven hundred and twenty fish with an initial body weight of（ 1. 53 ±0. 04） g were selected and randomly divided into 7 groups,including feeding with basal diet as control group（ G0 group）,continuous feeding with diets of different levels of β-glucan（ SG200,SG600 and SG1000 groups）,and interval feeding with diets of different levels of β-glucan for 7 days followed by the basal diet for 7 days（ IG200,IG600 and IG1000 groups）. The continuous feeding groups had 4 replicates,and control group and interval feeding groups all had 3 replicates,and each replicate had 30 fish. After the feeding trail,the fish were challenged with Aeromonas hydrophila for 96 h to calculate the accumulative mortality rate（ AMR）. The results showed as follows： 1） there were no significant differences in weight gain rate（ W GR）,feed conversion ratio（ FCR）,protein efficiency ratio（ PER） and survival rate（ SR） among 7 groups（ P〈0. 05）,but hepatosomatic index（ HSI） in IG1000 group was significantly lower than that in control group（ P〈0. 05）. Furthermore,the fish fed diets supplemented with β-glucan showed higher W GR and PER than the control group,and continuous fed diet supplemented with β-glucan showed higher W GR than interval fed diet supplemented with the same level of β-glucan,the highest values appeared in SG600 group. 2） Compared with the control group,the contents of crude protein,ether extract and ash of whole body in the other six groups were increased to some extent and the moisture content was decreased to some extend,but no significant differences were observed（ P〉0. 05）. 3） There were no significant differences in serum biochemical indices among all groups（ P〉0. 05）.However,compared with the control group,the contents of serum globulin（ GLB） and total protein（ TP） in SG1000 and IG600 group were higher,but the activities of serum glutamic oxalacetic transaminase（ GOT）and glutamic pyruvic transaminase（ GPT） in β-glucan supplementation groups were lower. 4） After Aeromonas hydrophila infection for 96 h,the AMR was 35 % to 46 % among all groups and there was no significant difference（ P〉0. 05）. In conclusion,except for HSI of interval feeding 1 000 mg / kg β-glucan is significantly decreased,supplementation of 200,600 and 1 000 mg / kg β-glucan to diets,using either continuous or interval feeding strategies,has no significant effects on growth performance,body composition,serum biochemical indices and resistance against Aeromonas hydrophila of juvenile yellowcatfish.