贝莱斯芽孢杆菌MSP05对泥鳅生长、消化及免疫的影响

Effects of Dietary Bacillus velezensis MSP05 on Growth Performance,Intestinal Digestive Capacity and Non-Specific Immune of Loach Misgurnus anguillicaudatus

为探究饲料中添加贝莱斯芽孢杆菌MSP05对泥鳅幼鱼生长、消化及非特异性免疫的影响,选取360尾初始平均体质量为(3.24±0.14)g的泥鳅幼鱼,分为4组,每组3个平行,对照组及3个试验组分别饲喂添加0、1×10^(6)、1×10^(7)、1×10^(8)cfu/g贝莱斯芽孢杆菌MSP05的日粮,养殖8周。试验结果显示:贝莱斯芽孢杆菌MSP05显著提高了泥鳅幼鱼的质量增加率和特定生长率(P<0.05);随着添加量的增加,蛋白酶、淀粉酶活性先升后降,并在1×10^(7)cfu/g组达到最大值,脂肪酶活性则不断升高;1×10^(6)cfu/g组泥鳅前肠、中肠形态指标提升效果最显著,1×10^(7)cfu/g组后肠形态最佳;相较于对照组,试验组血清过氧化氢酶、超氧化物歧化酶、溶菌酶、碱性磷酸酶活性显著提高,丙二醛含量显著降低(P<0.05);贝莱斯芽孢杆菌MSP05还显著降低了嗜水气单胞菌攻毒后泥鳅幼鱼的死亡率(P<0.05)。综上,饲料中添加贝莱斯芽孢杆菌MSP05能够显著促进泥鳅幼鱼生长,提高其消化酶、抗氧化酶活性,改善其肠道形态,提升其非特异性免疫及对嗜水气单胞菌的抗病力。

This study was conducted to investigate the effect of dietary Bacillus velezensis MSP05 on growth performance,digestion,and non-specific immune function of juvenile loach Misgurnus anguillicaudatus.360 fishes with an average initial body weight of(3.24±0.14)g were randomly assigned into 4 groups in triplicates with 30 individuals per replicate.One control group and three experimental groups were added 0,1×10^(6),1×10^(7),1×10^(8) cfu/g B.velezensis MSP05 to basal diets respectively.After 8 weeks of feeding,the results demonstrated that the weight gain rate(WGR)and specific growth rate(SGR)of the groups adding B.subtilis MSP05 were significantly higher than those of the control group(P<0.05).The activities of protease and amylase increased firstly and then decreased with the B.velezensis level increasing,achieving the highest value in 1×10^(7) cfu/g group,while the activities of lipase rose continuously.The optimal morphology of foregut,midgut and hindgut of loach were observed in 1×10^(6),1×10^(6),1×10^(7) cfu/g group,respectively.The activities of serum catalase(CAT),superoxide dismutase(SOD),lysozyme(LSZ)and alkaline phosphatase(ALP)in the serum were significantly higher than the control group(P<0.05),while MDA levels showed the opposite trend.Challenged by Aeromonas hydrophila for 15 days,the cumulative mortality rate of juvenile loaches decreased significantly fed with B.velezensis.In conclusion,the addition of B.velezensis MSP05 can significantly enhance the growth performance,digestive enzymes activity,intestinal morphology,antioxidant enzyme activity,non-specific immune function and disease resistance against A.hydrophila.