青贮玉米有氧暴露过程中营养品质及细菌群落多样性

青贮饲料营养品质的优劣很大程度上由其微生物组成决定，有氧暴露会引起微生物群落多样性发生变化。为探明有氧暴露后青贮玉米细菌多样性分布及其对青贮品质的影响，本试验对有氧暴露后0 h, 1 h, 8 h, 24 h, 36 h, 48 h, 72 h, 96 h, 120 h青贮玉米(Zea mays L.)的营养品质和细菌群落结构测定与分析。结果表明：青贮玉米在有氧暴露过程中可溶性糖、粗蛋白和干物质含量降低，中性洗涤纤维和酸性洗涤纤维含量上升，钙和磷含量变化不明显；有氧暴露过程中细菌多样性呈先升高后降低的趋势，在有氧暴露36 h时细菌多样性最高；有氧暴露不同时间，优势细菌门分别是厚壁菌门和放线菌门，优势细菌属为乳酸菌属；有氧暴露过程中厚壁菌门与可溶性糖和蛋白质含量呈极显著正相关关系，与中性洗涤纤维和酸性洗涤纤维含量呈极显著负相关关系；变形菌门和酸杆菌门细菌与可溶性糖含量呈负相关关系。综上所述，与生产实践相结合青贮玉米应该在有氧暴露8 h内完成饲喂。

Nutrient Quality and Bacterial Community Diversity of Silage Corn During Aerobic Exposure

The nutritional quality of silage is largely determined by its microbial composition,and aerobic exposure will cause changes in microbial community diversity. To investigate the distribution of bacterial diversity in silage maize after aerobic exposure and its impact on silage quality,the nutritional quality and bacterial community structure of silage maize at 0,1,8,24,36,48,72,96 and 120 hours after aerobic exposure were determined and analyzed.The results showed that the contents of soluble sugar,crude protein and dry matter of silage maize decreased during aerobic exposure. The content of neutral detergent fiber and acid detergent fiber increased,and the content of calcium and phosphorus did not change significantly. During aerobic exposure,bacterial diversity increased first and then decreased,and the bacterial diversity was the highest at 36 hours of aerobic exposure. At different times of aerobic exposure,the dominant bacteriophyta are Firmicutes and Actinobacteria,and the dominant bacteria genus is Lactobacillus. During aerobic exposure,Firmicutes was significantly positively correlated with soluble sugars and proteins,and negatively correlated with neutral detergent fibers and acid detergent fibers. Proteobacteria and Acidobacteria were negatively correlated with soluble sugars. To sum up,silage corn should be fed within 8 hours of aerobic exposure in combination with production practice.