优良抑菌活性乳酸菌对玉米青贮及有氧暴露期微生物数量和pH的影响

为了探讨乳酸菌对全株玉米青贮及有氧暴露后青贮饲料中乳酸菌、好氧细菌、酵母菌和霉菌数量及其pH的影响,进一步筛选出可提高青贮饲料品质和有氧稳定性的乳酸菌接种剂,将实验室前期从甘肃各地玉米秸秆青贮饲料中分离筛选获得的5株产酸快、多且具有抑菌活性的优良乳酸菌分别添加全株玉米进行青贮,分析青贮过程和有氧暴露后青贮饲料中乳酸菌、好氧细菌、酵母菌和霉菌数量的动态变化及pH。结果显示,在青贮过程和有氧暴露后,分别添加肠膜明串珠菌肠膜亚种B1-7、戊糖片球菌B2-3、植物乳杆菌B3-1、屎肠球菌B5-2和发酵乳杆菌E2-3的各处理组乳酸菌总数均显著高于对照组,而好氧细菌、酵母菌和霉菌数量均显著低于对照组,pH亦低于对照组。其中B1-7和B5-2处理组在青贮初期乳酸菌总数最多,从青贮第7天开始到有氧暴露的30 d内,始终是B3-1处理组乳酸菌总数最多,好氧细菌、酵母菌和霉菌数量最少、pH最低。以上结果表明这5株乳酸菌具有提高青贮饲料品质和有氧稳定性的潜力,其中植物乳杆菌B3-1的效果最好。

Effect of lactic acid bacteria on corn silage quality and stability after aerobic exposure

To investigate the effect of lactic acid bacteria (LAB)with antibacterial activity on the number of LAB,aerobic bacteria,yeasts and molds and pH of whole corn silage during fermentation and aerobic expo-sure,5 LAB strains collected from corn silage across Gansu were added to whole corn silage.The results showed that the number of LAB was significantly increased by adding LAB to silage and the number of aerobic bacteria,yeasts and molds significantly reduced and pH reduced after addition of Leuconostoc mesenteroides subsp.Mesenteroides B1-7,Pediococcus pentosaceu B2-3,Lactobacillus plantarum B3-1,Enterococcus faecium B5-2 and Lactobacillus fermentum E2-3 compared with the control (no LAB added).At the beginning of fer-mentation the number of LAB in B1-7 and B5-2 treatments was highest.After aerobic exposure (7 to 30 days),the number of LAB was highest,aerobic bacteria,yeasts and molds lowest,and pH lowest in the B3-1 strain treatment.These results indicate that all added LAB had a potential role in improving the quality of silage and aerobic stability but L.plantarum B3-1 was the most effective.