Saylor B A, Diepersloot E C, Heinzen C, McCary C L, Ferraretto L F
Department of Animal and Dairy Sciences, University of Wisconsin, Madison 53706.
Department of Animal Sciences, University of Florida, Gainesville 32608.
JDS Commun. 2021 Jun 23;2(4):191-195. doi: 10.3168/jdsc.2021-0093. eCollection 2021 Jul.
The objective of this experiment was to analyze the effect of kernel breakage on the fermentation profile, nitrogen fractions, and ruminal in vitro starch digestibility of whole-plant corn silage and ensiled corn grain. Whole corn plants were harvested, and ears were separated from the forage portion and shelled. Corn kernels were either left intact or broken manually using a hammer. The remaining forage portion of the corn plants was chopped. Samples of the intact and broken kernels were stored for 0 or 30 d in quadruplicate vacuum pouches. Remaining intact and broken kernels were each reconstituted with the chopped forage portion of the corn plant to simulate whole-plant corn forage and were also stored for 0 or 30 d. In kernels separated from whole-plant corn silage, kernel form had no effect on zein protein concentrations. However, it was observed that in vitro starch digestibility at 7 h increased with ensiling only in kernels that were broken. When corn kernels were ensiled alone, concentrations of soluble crude protein and ammonia nitrogen increased with ensiling to a greater extent when kernels were broken. Finally, fermentation of ensiled corn grain was enhanced when kernels were broken. Overall, this study gives insight into the importance of kernel breakage to improve starch digestibility in corn silage through means other than a reduction in particle size and opens the door for continued investigation into the proteolytic activity occurring in the silo.
本实验的目的是分析籽粒破损对全株玉米青贮饲料和青贮玉米粒的发酵特性、氮组分以及瘤胃体外淀粉消化率的影响。收获全株玉米，将果穗与草料部分分离并脱粒。玉米粒要么保持完整，要么用锤子手动敲碎。将玉米植株剩余的草料部分切碎。完整和破碎的玉米粒样本在一式四份的真空袋中储存0天或30天。将剩余的完整和破碎玉米粒分别与玉米植株切碎的草料部分重新混合，以模拟全株玉米草料，同样储存0天或30天。在从全株玉米青贮饲料中分离出的玉米粒中，籽粒形态对玉米醇溶蛋白浓度没有影响。然而，观察到仅在破碎的玉米粒中，青贮7小时后的体外淀粉消化率随青贮时间增加。当玉米粒单独青贮时，破碎的玉米粒中可溶性粗蛋白和氨态氮的浓度随青贮时间增加的幅度更大。最后，破碎的玉米粒青贮时发酵得到增强。总体而言，本研究揭示了籽粒破损对于通过减小颗粒尺寸以外的方式提高玉米青贮饲料中淀粉消化率的重要性，并为继续研究青贮窖中发生的蛋白水解活性打开了大门。
