摘要
This study investigated the effect of substituting barley grain with wheat on rumen fermentation, bacterial communities, nutrient digestibility and plasma metabolites in finishing feedlots steers. The experiment was designed as a replicated 4×4 Latin square with 8 rumen cannulated steers (742±44 kg) fed diets in which wheat was substituted for 0, 30%, 60% or 89% of barley grain dry matter (DM). All grains were dry-rolled to a processing index (PI) of 80% expressed as a percentage of volume weight of processed grain divided by the volume weight of unprocessed grain. The remaining dietary ingredients consisted of 6% barley silage and 5% supplement. Duration of pH below 5.8 linearly increased (P=0.04) with increasing levels of wheat, whereas average, minimum and maximum pH as well as the time and area under pH 5.5 (P=0.08) and 5.2 (P=0.18) did not differ among diets. Likewise, volatile fatty acids (VFA) profiles, concentrations of VFA, ammonia, numbers of protozoa and total tract digestibility of nutrients were unaffected (P>0.05) by this substitution. Increasing levels of wheat linearly increased copy numbers of 16S rRNA for total bacteria (P=0.01) and Ruminococcus amylophilus (P=0.04) per g of rumen contents. Inclusion of wheat in the diet linearly reduced plasma albumin (P=0.03) and urea nitrogen (P=0.01) concentrations, but did not affect (P>0.05) other major plasma metabolites. In conclusion, replacing barley grain with wheat in the diets of feedlot steers had little negative impact on nutrient digestibility or rumen fermentation, however, it increased the daily duration that rumen pH remained below 5.8. These data suggest that there is little difference in the ruminal fermentation or digestibility of barley vs wheat if both grains are processed to a similar degree.
摘要译文
这项研究调查了瘤胃发酵，细菌群落，营养物质的消化率和血浆代谢物整理肉牛育肥场代替大麦小麦的影响。实验设计与8瘤胃瘘管阉牛（742±44千克）日粮中小麦替代0，30％，25，60％，25或89％，重复4×4拉丁方25的大麦籽粒干物质（DM）。所有颗粒进行干轧至80％的处理指数（PI）25表示为加工的谷物由未处理颗粒的体积重量除以体积重量百分比。剩余的食品成分包括了6％25大麦青贮和5％25补充。pH值低于5.8的持续时间在pH 5.5（p = 0.08）和5.2（p = 0.18）没有显着差异呈线性增加（P = 0.04）的增加小麦的水平，而平均，最小和最大pH值以及时间和面积其中饮食。同样地，挥发性脂肪酸（VFA）型材，VFA浓度，氨，原生动物和养分总消化道消化率的数目并没有受到影响（差异无显着0.05）由该替换。小麦的水平增加呈线性增加的16S rRNA基因的细菌总数（P = 0.01），每克瘤胃内容物瘤胃amylophilus（P = 0.04）拷贝数。小麦的饮食中的夹杂物线性地减少血浆白蛋白（P = 0.03），尿素氮（P = 0.01）的浓度，但不影响（差异无显着0.05）等主要血浆代谢产物。最后，更换大麦谷物小麦在饲养场阉牛的饲料对营养物质的消化率或瘤胃发酵小的负面影响，但是，它增加了瘤胃pH值保持低于5.8的每日持续时间。这些数据表明，有如果两个晶粒被处理以类似程度的瘤胃发酵或大麦VS小麦消化率差别不大。
M.L. He[a][b]; J. Long[a]; Y. Wang[a]; G. Penner[b]; T.A. McAllister[a]. Effect of replacing barley with wheat grain in finishing feedlot diets on nutrient digestibility, rumen fermentation, bacterial communities and plasma metabolites in beef steers[J]. Livestock Science, 2015,176: 104–110