三株芽孢杆菌抑菌活性分析及对肉鸡舍空气微生物的影响

【目的】分析2株解淀粉芽孢杆菌（Bacillus amyloliquefaciens）和1株苏云金芽孢杆菌（Bacillus thuringiensis）的基本特性以及对大肠埃希氏菌（Escherichia.coli，CVCC1570）的抑制活性；分析3株芽孢杆菌复合制剂对肉鸡舍空气大肠杆菌和金黄色葡萄球菌的抑制作用，为改善畜舍环境提供基础数据。【方法】对3株芽孢杆菌进行形态学观察、镜检和生长曲线测定，以大肠埃希氏菌（CVCC1570）为指示菌株，采用琼脂扩散法对单一菌株的抑菌特性进行测定，筛选出适宜的抑菌浓度；利用三因子三水平的正交试验设计，筛选出最佳抑菌效果的复合芽孢杆菌组合；鸡舍喷洒试验采用单因子设计，分为3个处理组，每个处理设3个重复，分别为空白对照组，化学消毒剂阳性对照组（苯扎氯铵），喷洒复合芽孢杆菌菌剂处理组。在肉鸡不同日龄检测鸡舍内大肠杆菌和金黄色葡萄球菌的变化规律。【结果】3株芽孢杆菌为革兰氏阳性需氧菌。芽孢杆菌SKN01和芽孢杆菌SKN02生长曲线相近，在培养2h开始进入对数生长期。芽孢杆菌SKN03生长较缓慢，进入对数生长期的时间相对较长。单一菌株对大肠埃希氏菌有效抑菌浓度均为108CFU•mL-1。经正交试验测定，3株芽孢杆菌复合菌液最佳抑菌组合为4×108 CFU•mL-1、4×108 CFU•mL-1、6×108 CFU•mL-1。最佳组合复合芽孢杆菌喷洒鸡舍，能够有效抑制大肠杆菌和金黄色葡萄球菌的生长，在肉鸡生长后期复合制剂的抑菌效果明显。【结论】3株芽孢杆菌能够有效抑制大肠埃希氏菌，同时复合菌液能够有效减少鸡舍有害微生物的数量，起到改善鸡舍环境的作用。

Comparative Studies on the Bacteriostatic Activity of the Three Bacillus Strains and Its Effects on Air Microorganisms in Broiler House

【Objective】The present study was conducted to evaluate the biological characteristics of 2 strains of Bacillus amyloliquefaciens and 1 strain of Bacillus thuringiensis, and the bacteriostatic activity of these three bacillus strains against Escherichia coli. After being sprayed the mixture of three bacillus suspension to the broiler house, the number of E.coli and staphylococcus aureus in the air was detected in order to evaluate the effect of bacillus on improvment of environment.【Method】In this study, the colony morphology and the growth curve of the three bacillus were examined. All of the three bacteria were examined for their antimicrobial activity against E. coli (CVCC1570) by using the agar diffusion system. The optimum combination level of the three bacteria in the mixed product was investigated by using the orthogonal design in three factors and three levels. The mixed product of the three bacillus strains was sprayed in the poultry house. Three houses were selected, one for blank control(A), one for chemical disinfectant (benzalkonium chloride) as positive control(B), and one for bacillus treatment(C). Each treatment contained three replications. The numbers of E.coli and Staphylococcus aureus in the air of the poultry house were detected every week.【Result】The results showed that all strains appeared as Gram-positive and aerobic bacillus. Bacillus SKN01, Bacillus SKN02 had the similar growth curve entering the logarithmic phase in the first two hours. Bacillus SKN03 grew slowly and spent long time to enter the logarithmic phase. The effective bacteriostatic activity concentration of single bacillus strain against E. coli (CVCC1570) was 108 CFU•mL-1. The most effective concentration of antimicrobial activity in the mixture of three bacillus strains was 4×108CFU•mL-1, 4×108CFU•mL-1 and 6×108CFU•mL-1. Spraying the mixture of bacillus suspension in the broiler house could effectively reduce the number of E.coli and S. aureus in the air, especially at the later growth stage of chickens.【Conclusion】The bacillus strain had antimicrobial activity against E.coli. Spraying the mixture of the three bacillus suspension in the broiler house could reduce the number of E.coli and S. aureus in the air and could improve the environment effectively.