同/异质型乳酸菌对苏丹草青贮饲料有氧暴露过程中酵母菌群落的影响

Effect of homo-and hetero-fermentative lactic acid bacteria on yeast community during the aerobic exposure process of sudangrass silage

试验研究同/异质型乳酸菌添加对苏丹草青贮饲料发酵品质及有氧暴露过程中酵母菌群落动态的影响。试验分别设置对照(CK组)、植物乳杆菌(LP组)、鼠李糖乳杆菌(LR组)和布氏乳杆菌(LB组)4个处理组。苏丹草青贮发酵60d,在有氧暴露的第0、2、4、6、8d进行酵母菌群落动态及pH值的测定。结果显示,添加同/异质型乳酸菌显著降低苏丹草青贮饲料的pH值、丁酸以及氨态氮含量(P<0.05),显著增加苏丹草青贮饲料的乳酸含量、乳酸/乙酸、乳酸菌浓度和V-score(P<0.05)。V-score评分从高到低依次为LP组>LB组>LR组>CK组。与对照组相比,添加同/异质型乳酸菌显著提高苏丹草青贮饲料的有氧稳定时间(P<0.05),LB处理下的有氧稳定时间最长(159h)。随着有氧暴露天数的延长,所有处理组苏丹草青贮饲料中,拜氏接合酵母比例不断提高,青贮饲料的pH值均逐渐升高,LB处理对酵母菌的抑制效果最好。试验表明,在制作青贮饲料时同时使用同/异质性乳酸菌添加剂可以改善青贮饲料的发酵品质,并提高其有氧稳定性。

The experiment studied the effect of homo-and hetero-fermentative lactic acid bacteria addition on the fermentation quality and the dynamics of yeast community during aerobic exposure to Sultanas silage.The experiment set up four group of control(CK group),Lactobacillus plantarum(group LP),Lactobacillus rhamnosus(group LR)and Lactobacillus brucei(group LB).The indexes of fermentation characteristic after 60 d ensiling and the dynamic change of yeast community and the pH value during the aerobic exposure process(0,2,4,6,8 d)were analyzed.The results showed that the addition of homo-and hetero-fermentative lactic acid bacteria the pH value,butyric acid and ammonia nitrogen were significantly decreased(P<0.05),and significantly increased the lactic acid,lactic acid/acetic acid,lactic acid bacteria and V-score(P<0.05).The order of V-score score from high to low was group LP>group LB>group LR>group CK.The order of V-score from high to low was group LP>group LB>group LR>group CK.Compared with the control group,the addition of homo-and hetero-fermentative lactic acid bacteria significantly increased the aerobic stability(P<0.05),the best aerobic stability was group LB(159h).With the extension of aerobic exposure process,the proportion of Zygosaccharomyces bailii in all treatments were increased.The best aerobic stability and the least type of yeasts was in LB treatment.With the extension of aerobic exposure process,the pH value in all treatments were increased.The best inhibition effect on yeast during aerobic exposure was LB treatment.The experiment indicates that the simultaneous use of homogeneous/heterogeneous lactic acid bacteria additives in the production of silage can improve the fermentation quality of silage and increase its aerobic stability.