禽用乳酸菌的筛选与功能鉴定

Isolation and functional identification of lactic acid bacteria for poultry

【目的】从健康鸡肠道中分离筛选优质乳酸菌,为制备禽用微生态制剂提供技术支持。【方法】选用30日龄健康青年鸡,取其盲肠内容物,通过选择性培养基筛选出具有产酸能力的乳酸菌,对其进行耐pH 3.0胃酸和3g/L牛胆盐筛选试验及菌株生长曲线、产酸能力测定,并通过平板抑菌试验筛选出具有较强抑菌效果的菌株。最后对此菌株16SrRNA进行克隆测序,经Blast比对和系统进化树分析,对菌株进行鉴定。【结果】从所取鸡盲肠内容物中分离得到L1~L9 9株乳酸菌,其中L2、L4和L9株耐pH 3.0和3g/L牛胆盐的综合能力较强。经过比较3株菌的生长曲线和产酸曲线,发现L2菌株耐酸耐牛胆盐、生长迅速、产酸能力强,且具有较强的抑制致病性大肠埃希菌的活性。经16SrRNA序列比对和系统进化树鉴定,确定L2为唾液乳酸杆菌。【结论】成功筛选出了1株可用以研制禽用微生态制剂的乳酸菌菌株。

【Objective】A lactic acid bacteria was isolated from healthy chickens gut to provide technical support for preparing micro-ecological preparation used in poultry.【Method】Samples were collected from cecum of 30 day old healthy chicken,and lactic acid producing bacteria were screened through selective medium.After being screened by resistance to pH 3.0hydrochloric acid and 3g/L bile salts,the growth and acidogenicity of screened strains were determined,and the strain with strong antibacterial ability was screened through plate bacteriostatic experiment.Finally,it was identified by 16 SrRNA sequencing,blast alignment and phylogenetic analysis.【Result】Nine lactic acid bacteria strains（L1-L9）were isolated from chicken cecum,and L2,L4 and L9had strong resistance to 3g/L bile salt and pH 3.0.After comparing the growth performance and acid production of the three bacteria,L2 strain was the best with fast growth,high acid producing ability,and strong activity in inhibiting pathogenic Escherichia coli.L2 was identified as Lactobacillus saliva by 16 SrRNA and phylogenetic tree analysis.【Conclusion】One Lactobacillus,whichcould be used for preparing micro-ecological preparation for poultry,was screened successfully.