益生菌ZD02的分离及其在对虾集约化精养中的应用

Isolation of Bacillus subtilis ZD 02 and its application in intensive culture of Litopenaeus vannamei

从养殖环境分离纯化芽孢杆菌6株,对其进行消化酶活检测,根据检测的酶活指标选择ZD02作为待试验菌株并进行鉴定和热稳定性检测。结果表明:ZD02被鉴定为枯草芽孢杆菌,具有耐受高温的特性,90℃水浴10min存活率93%,95℃水浴5min存活率93%,100℃水浴5min存活82%,95℃和100℃水浴2min不影响芽孢菌存活,在调质温度102℃条件下,制粒后芽孢菌存活率94%;将经过鉴定的枯草芽孢杆菌发酵培养后应用于凡纳滨对虾(Litopenaeus vannamei)的集约化精养殖,试验组A在基础饲料中添加0.3%的芽孢杆菌。试验组B保持配方成本不变的基础上添加0.3%的芽孢杆菌,结果显示,试验组的成活率显著高于对照组(P<0.05),试验组A、B的产量分别比对照组提高了43.0%和36.7%(P<0.05),产值分别提高35.4%和21.0%(P<0.05),饲料系数比对照组分别降低了9.9%和8.7%(P<0.05);换水耗电、水质调节剂、内服药物3项费用合计,A组和B组较对照组分别节省了21.3%和22.3%(P<0.05);实验组之间各项指标差异不显著(P>0.05);表明,在对虾的集约化精养过程中合理利用益生芽孢杆菌可以增产增收。

Six strains of Bacillus spp. were isolated and screened from the environment of aquaculture, and their protease and amylase activities were determined. Based on the determination of the activities of the two digestive enzymes, the strain ZD 02 was selected as test object, and its heat-stability was evaluated. The strain ZD 02 identified as Bacillus subtilis had higher tolerance to high temperature. Its survival rate at 90 ℃ for 10 min, 95 ℃ for 5 min, and 100 ℃ for 5 min was 93%, 93%, and 82%, respectively. At 95 ℃ and 100 ℃ for 2 min, the survival rate of the strain was less affected. Moreover, the survival rate of ZD 02 remained 94% at 102℃after adding other feed materials and manufactured into grains. Then, the ZD 02 was cultured through fermentation, and applied to the intensive culture of Litopenaeus vannamei. Three experimental groups were installed. In control group, only basal diet provided by Guangdong Evergreen Group Co., Ltd. was added; in group A, basal diet amended with 0.3% B. subtilis was supplied; in group B, 0.3% B. subtilis was applied on the basis of unchanged cost of diet description. The results showed that the survival rate of L. vannamei in experimental groups A and B was higher than that in control group （P〈0.05）. Compared with the control, the output of groups A and B increased by 43.0% and 36.7% （P〈0.05）, production value increased by 35.4% and 21.0% （P〈0.05）, feed conversion ratio decreased by 9.9% and 8.7%, （P〈0.05）, expenses including regulation substances of aquaculture, medicines, and energy expending were economized by 21.3% and 22.3%, respectively （P〈0.05）. No significant differences were observed in the survival rate, output, production value, feed conversion ratio, and such expenses as medicines and energy expending between groups A and B （P〈0.05）. The results demonstrated that the reasonable application of B. subtilis in aquaculture could promote the output and production value of L. vannamei.