添加不同乳酸菌对玉米秸秆青贮有氧稳定性影响的研究

Effect of Adding Different Lactic Acid Bacteria on Aerobic Stability of Corn Straw Silage

[目的]筛选可供玉米秸秆青贮发酵利用的复合乳酸菌系。[方法]以前期研究筛选得到的同型发酵乳酸菌AS06株和异型发酵乳酸菌BS26株为试验材料,设置4种不同的乳酸菌添加处理方式,即对照处理组(CK组)、同型乳酸菌AS06株发酵处理组(LP组)、异型发酵乳酸菌BS26株处理组(LB组)、同型乳酸菌AS06株+异型发酵乳酸菌BS26株混合处理组(LBP组),进行玉米秸秆青贮发酵试验。测定并比较各处理组玉米秸秆青贮的有氧暴露后pH值、微生物菌群、乳酸含量、有机酸含量、可溶性碳水化合物(WSC)含量,以及有氧稳定性时长。[结果]添加异型发酵乳酸菌BS26株及复合乳酸菌系(异型发酵乳酸菌BS26株+同型发酵乳酸菌AS06株)的玉米秸秆,开封后青贮pH值上升缓慢,乳酸含量下降缓慢,WSC的营养损失有效减少,酵母菌和霉菌的生长得到明显抑制,青贮有氧稳定性时长分别达到208 h和147 h。[结论]异型发酵乳酸菌单独或与同型发酵乳酸菌复合添加,可有效抑制玉米秸秆青贮的有氧腐败,且前者有氧稳定性效果更好。

[Objective]To screen the composite lactic acid bacteria strains for preparation of corn straw storage.[Method]The homofermentative lactic acid bacteria AS06 strain and the heterofermentative lactic acid bacteria BS26 strain obtained in previous study were used as experimental materials to perform corn straw silage fermentation test.Four different treatments of lactic acid bacteria addition were set,including the control treatment group(CK group),the AS06 strain fermentation treatment group(LP group),BS26 strain fermentation treatment group(LB group)and mixed fermentation treatment group(LBP group)with AS06 strain and BS26 strain.The pH value,microbial flora,contents of lactic acid,organic acid and soluble carbohydrates(WSC),and aerobic stability duration of the fermented corn straw silage in different groups after oxygen exposure were determined and assessed.[Result]The corn straw fermented with BS26 strain(LB group)or composite lactic acid bacteria of AS06 strain and BS26 strain(LBP group)had slowly increased pH value and slowly reduced lactic acid content after oxygen exposure.Furthermore,in both of the above fermentation products,the nutritional loss of WSC was effectively reduced,the growth of yeast and mold was significantly inhibited,and the aerobic stability duration reached up to 208 h(LB group)and 147 h(LBP group),respectively.[Conclusion]Addition of heterofermentative lactic acid bacteria alone or in combination with homofermentative lactic acid can effectively suppress the aerobic corruption during fermentation of corn straw silage,and the former performed better in aerobic stability.