Corn silage quality under delayed sealing and microbial inoculant use

Abstract The objective of this work was to determine the effects of sealing delay for 12 hours and of the use of microbial inoculant with heterofermentative bacteria on whole-plant corn (Zea mays) silage. The experimental design was completely randomized in a 2×2 factorial arrangement (with or without inoculant × with or without sealing delay). Silage was evaluated for: chemical composition in vitro dry matter digestibility (IVDMD), fermentative parameters, losses, aerobic stability, and microbiological profile. The heating of the silage caused by respiration increased the contents of neutral detergent insoluble protein and of acid detergent insoluble protein by 77 and 27.3%, respectively. Soluble carbohydrate losses increased the contents of neutral detergent fiber corrected for ash and protein by 9.1% and of acid detergent fiber by 5.1%, but decreased the content of nonfibrous carbohydrates by 11.2%. IVDMD did not differ between treatments. Silages with delayed sealing and the inoculant showed higher pH and contents of acetic acid, propionic acid, and ammoniacal nitrogen, but a lower content of lactic acid. Delayed sealing reduces the nutritional value, increases the fibrous fractions, and decreases the soluble carbohydrates, whereas the use of inoculant does not improve the nutritional value and aerobic stability of the silages.摘要 本研究旨在探究12小时密封延迟与异型发酵细菌微生物接种剂的使用对全株玉米（Zea mays）青贮饲料的影响。试验采用2×2因子完全随机设计，设置两个因子：是否使用微生物接种剂、是否存在密封延迟。本研究对青贮饲料的化学组成、体外干物质消化率（in vitro dry matter digestibility, IVDMD）、发酵参数、损耗情况、有氧稳定性及微生物群落特征进行了测定与分析。呼吸作用引发的青贮料发热，使中性洗涤不溶性蛋白与酸性洗涤不溶性蛋白含量分别提升77%与27.3%。可溶性碳水化合物的损耗使得校正灰分与蛋白质的中性洗涤纤维含量提升9.1%、酸性洗涤纤维含量提升5.1%，但使非纤维性碳水化合物含量降低11.2%。各试验组的体外干物质消化率无显著差异。同时采用接种剂且存在密封延迟的青贮料，其pH值、乙酸、丙酸及氨态氮含量更高，但乳酸含量更低。密封延迟会降低青贮饲料的营养价值，提升纤维组分占比并减少可溶性碳水化合物含量，而使用微生物接种剂未能改善青贮饲料的营养价值与有氧稳定性。