牛源抗氧化芽孢杆菌的分离鉴定及生物特性研究

【目的】从奶牛瘤胃中分离具有抗氧化能力且耐受性好的芽孢杆菌，为牛源益生菌作为抗氧化添加剂使用提供理论依据及参考。【方法】采集3头成年荷斯坦奶牛瘤胃内容物，通过细菌分离纯化、形态观察、生化检测及16S rDNA分子检测进行鉴定，同时检测筛选菌株的超氧自由基和羟自由基清除率、耐酸、耐胆盐能力及对抗生素的耐药性。【结果】从奶牛瘤胃液中共获得了12株菌，通过特异性培养基与革兰氏染色共筛选出5株芽孢杆菌(X-1～X-5)。对5株芽孢杆菌进行分子鉴定，确定X-1为热噬淀粉芽孢杆菌，X-2为短小芽孢杆菌，X-3为解蛋白芽孢杆菌，X-4为枯草芽孢杆菌，X-5为沙福芽孢杆菌。抗氧化能力检测结果显示，5株菌均具有一定的抗氧化能力，X-5菌株抗氧化能力最高，超氧自由基和羟自由基清除率分别达到73.81%和73.54%。当pH为2.5时，5株芽孢杆菌存活率均在25%以上；胆盐浓度为0.6%时，5株芽孢杆菌存活率均在60%以上，说明菌株具有良好的耐受性。药敏试验结果显示，试验分离出来的大多数菌株对氧氟沙星、呋喃妥因、红霉素等高度敏感；对头孢呋辛、头孢噻肟、链霉素等耐受；对卡那霉素、环丙沙星、氨苄西林等中度敏感。...

Isolation,Identification and Biological Characteristics of Antioxidant Bacillus from Cattle

【Objective】 This study was aimed to isolate Bacillus with antioxidant capacity and good tolerance from the rumen of dairy cows, so as to provide theoretical basis and reference for the use of bovine probiotics as antioxidant additives.【Method】 The rumen contents of 3 adult Holstein cows were collected and identified by bacterial isolation and purification, morphological observation, physiological and biochemical detection and 16S rDNA molecular detection.The scavenging rates of superoxide free radicals and hydroxyl free radicals, acid resistance, bile salt resistance and antibiotic resistance of the screened strains were also detected.【Result】 A total of 12 strains of Bacillus were isolated from rumen fluid of dairy cows, and 5 strains of Bacillus (X-1 to X-5) were screened by specific medium and Gram staining.Five strains of Bacillus were identified by molecular identification, and X-1 was identified as Bacillus thermoamylovorans, X-2 as Bacillus pumilus, X-3 as Bacillus proteolyticus, X-4 as Bacillus subtilis, and X-5 as Bacillus safensis.The results of antioxidant capacity test showed that all strains had certain antioxidant capacity, and strain X-5 had the highest antioxidant capacity, with the scavenging rates of superoxide free radicals and hydroxyl free radicals being 73.81% and 73.54%, respectively.When pH was 2.5, the survival rates of 5 Bacillus strains were all more than 25%.When the bile salt concentration was 0.6%, the survival rates of five Bacillus strains were all more than 60%, indicating that the strains had good tolerance.The results of drug sensitivity test showed that most of the isolates were highly sensitive to ofloxacin, nitrofurantoin, erythromycin and so on.It was resistant to cefuroxime, cefotaxime, streptomycin and so on.It was moderately sensitive to several drugs such as kanamycin, ciprofloxacin and ampicillin.【Conclusion】 The isolated Bacillus from cattle in this study had antioxidant capacity, and some of the strains had good acid resistance and bile salt resistance, which provided theoretical basis and reference for the use of Bacillus from cattle as antioxidant additives.