Abstract Increasing the length of storage of whole-plant corn silage (WPCS) has been shown to increase ruminal in vitro starch digestibility by facilitating hydrolysis of the protein matrix surrounding starch granules. It is possible that microbial inoculants could improve fermentation, thereby enhancing proteolytic activity in the silo. Additionally, microbial inoculants have potential to reduce or prevent the growth of toxigenic fungi in silage. Therefore, the objective of this study was to determine the effects of storage length and microbial inoculation with heterofermentative and homofermentative inoculants containing Enterococcus faecium on the fermentation profile, N fractions, and ruminal in situ starch disappearance of whole-plant corn silage, as well as the effect of microbial inoculation on silage mycotoxin concentrations. Whole-plant corn (333 ± 10 g of DM/kg as-fed) was ensiled in quintuplicate vacuum pouches untreated (CON) or after the following treatments: E. faecium at 1.5 × 105 cfu/g (EF); Lactobacillus plantarum at 1 × 105 and E. faecium at 5 × 104 cfu/g of fresh forage (LPEF); and L. buchneri and Lactococcus lactis at 1.5 × 105 cfu/g (LBLL). Silos were stored for 0, 30, 60, 90 or 120 d. Silage pH was greater with LBLL compared to the other three treatments (P = 0.005). Total acids were greater with LPEF than EF (P = 0.005). Ammonia-N (expressed as g/kg of N) was greatest with CON compared to the other treatments (P = 0.001). Concentrations of lactic acid were lower, and concentrations of acetic acid were greater with LBLL compared to the other treatments (P = 0.001). An interaction between microbial inoculation and storage length was observed for soluble CP concentrations as well as ruminal in situ starch disappearance (P = 0.001 and P = 0.012, respectively). Soluble CP (expressed as g/kg of CP) was greater with CON compared to the other treatments at d 30 and 90, but not different at d 60 and 120. Ruminal in situ starch disappearance was reduced for CON compared to the other three treatments at d 60 and 90. However, at d 120, ruminal in situ starch disappearance was similar across all treatments. Overall, the use of microbial inoculants improved fermentation profile. Microbial inoculation also increased starch disappearance in the earlier stages of fermentation but by 120 d of storage, starch disappearance was similar between inoculated silage and CON. Results from this study failed to support the hypothesis that microbial inoculants would reduce mycotoxin contamination.

中文翻译：

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微生物接种和贮藏时间对全株玉米青贮发酵曲线、氮组分和瘤胃原位淀粉消失的影响

摘要 增加全株玉米青贮饲料 (WPCS) 的储存时间已被证明可通过促进淀粉颗粒周围蛋白质基质的水解来增加瘤胃体外淀粉消化率。微生物接种剂可能会改善发酵，从而增强筒仓中的蛋白水解活性。此外，微生物接种剂具有减少或防止青贮饲料中产毒真菌生长的潜力。因此，本研究的目的是确定储存时间和微生物接种含有屎肠球菌的异发酵和同发酵接种物对全株玉米青贮饲料的发酵曲线、N 部分和瘤胃原位淀粉消失的影响，以及微生物接种对青贮霉菌毒素浓度的影响。将整株玉米（333 ± 10 g DM/kg 饲喂）青贮在未经处理 (CON) 或经过以下处理的五重真空袋中： 屎肠球菌 1.5 × 105 cfu/g (EF)；1 × 105 的植物乳杆菌和 5 × 104 cfu/g 新鲜草料 (LPEF) 的粪肠球菌；布氏乳杆菌和乳酸乳球菌，浓度为 1.5 × 105 cfu/g (LBLL)。筒仓储存 0、30、60、90 或 120 天。与其他三种处理相比，LBLL 的青贮 pH 值更高 (P = 0.005)。LPEF 的总酸大于 EF (P = 0.005)。与其他处理相比，CON 的氨氮（以 g/kg N 表示）最大（P = 0.001）。与其他治疗相比，LBLL 的乳酸浓度较低，醋酸浓度较高（P = 0.001）。对于可溶性 CP 浓度以及瘤胃原位淀粉消失，观察到微生物接种和储存时间之间的相互作用（分别为 P = 0.001 和 P = 0.012）。与其他处理相比，CON 的可溶性 CP（以 g/kg CP 表示）在第 30 天和第 90 天高于其他处理，但在第 60 天和第 120 天没有差异。与其他三种处理相比，CON 的瘤胃原位淀粉消失减少在第 60 天和第 90 天。然而，在第 120 天，所有处理的瘤胃原位淀粉消失相似。总体而言，微生物接种剂的使用改善了发酵曲线。在发酵的早期阶段，微生物接种也增加了淀粉的消失，但到储存 120 天，接种的青贮饲料和 CON 之间的淀粉消失是相似的。