摘要
The continuous trend for a narrowing margin between feed cost and milk prices across dairy farms in the United States highlights the need to improve and maintain feed efficiency. Yeast culture products are alternative supplements that have been evaluated in terms of milk performance and feed efficiency; however, less is known about their potential effects on altering rumen microbial populations and consequently rumen fermentation. Therefore, the objective of this study was to evaluate the effect of yeast culture supplementation on lactation performance, rumen fermentation profile, and abundance of major species of ruminal bacteria in lactating dairy cows. Forty mid-lactation Holstein dairy cows (121 ± 43 days in milk; mean ± standard deviation; 32 multiparous and 8 primiparous) were used in a randomized complete block design with a 7-d adaptation period followed by a 60-d treatment period. Cows were blocked by parity, days in milk, and previous lactation milk yield and assigned to a basal total mixed ration (TMR; 1.6 Mcal/kg of dry matter, 14.6% crude protein, 21.5% starch, and 38.4% neutral detergent fiber) plus 114 g/d of ground corn (CON; n = 20) or basal TMR plus 100 g/d of ground corn and 14 g/d of yeast culture (YC; n = 20; Culture Classic HD, Cellerate Yeast Solutions, Phibro Animal Health Corp.). Treatments were top-dressed over the TMR once a day. Cows were individually fed 1 × /d throughout the trial. Blood and rumen fluid samples were collected in a subset of cows (n = 10/treatment) at 0, 30, and 60 d of the treatment period. Rumen fluid sampled via esophageal tubing was analyzed for ammonia-N, volatile fatty acids (VFA), and ruminal bacteria populations via quantitative PCR amplification of 16S ribosomal DNA genes. Milk yield was not affected by treatment effects. Energy balance was lower in YC cows than CON, which was partially explain by the trend for lower dry matter intake as % body weight in YC cows than CON. Cows fed YC had greater overall ruminal pH and greater total VFA (mM) at 60 d of treatment period. There was a contrasting greater molar proportion of isovalerate and lower acetate proportion in YC-fed cows compared with CON cows. Although the ruminal abundance of specific fiber-digesting bacteria, including Eubacterium ruminantium and Ruminococcus flavefaciens, was increased in YC cows, others such as Fibrobacter succinogenes were decreased. The abundance of amylolytic bacteria such as Ruminobacter amylophilus and Succinimonas amylolytica were decreased in YC cows than CON. Our results indicate that the yeast culture supplementation seems to promote some specific fiber-digesting bacteria while decreasing amylolytic bacteria, which might have partially promoted more neutral rumen pH, greater total VFA, and isovalerate.
摘要译文
美国乳制品农场饲料成本和牛奶价格之间窄幅缩小的持续趋势强调了提高和维持饲料效率的必要性。酵母培养产品是在牛奶性能和饲料效率方面进行评估的替代补充剂;然而，对它们对改变瘤胃微生物群体的潜在影响而言，较少，并因此已知并因此瘤胃发酵。因此，本研究的目的是评估酵母培养物补充对泌乳乳奶奶牛泌乳奶牛瘤瘤细菌主要物种的影响。四十个中泌乳荷斯坦奶牛（牛奶中的121±43天;平均值±标准差; 32个多环和8个初级）用于随机完整块设计，具有7-D适应期，然后进行60 d治疗时间。奶牛被额定，牛奶日和以前的哺乳期乳屈服，并分配给基础总混合配给（TMR; 1.6 mcal / kg干物质，14.6％粗蛋白，21.5％淀粉和38.4％中性洗涤剂纤维）加114g / d地玉米（CON; n = 20）或基础TMR加上100g / d地玉米和14克/ d的酵母培养物（YC; n = 20;培养经典HD，Cellerd酵母溶液，PHIBRO动物健康公司。治疗每天一次穿着TMR。奶牛在整个试验中单独喂食1×/ d。在治疗期的0,30和60d的奶牛（n = 10 /处理）的子集中收集血液和瘤胃液相。通过定量PCR扩增分析通过食管管取样通过食管管取样的瘤胃流体，通过定量PCR扩增16S核糖体DNA基因。牛奶产量不受治疗效果的影响。在YC奶牛的能量平衡比CON较低，这部分地解释了较低干物质摄入的趋势，因为YC奶牛的体重低于孔。喂养Yc的奶牛在60 d治疗期间具有更高的整体瘤胃pH和更高的总VFA（mm）。与孔奶牛相比，在YC喂养牛中具有对比的摩尔比例和在YC喂养牛中的乙酸盐比例。虽然在YC奶牛中增加了特异性纤维消化细菌的瘤胃消化细菌，包括有uumacterium umacterium和喇叭杆菌，但在Yc奶牛中增加了纤维杆菌琥珀酰琥珀因酰胺的其他。在YC奶牛中降低了戊杆菌淀粉胺和琥珀酰亚胺淀粉钼等淀粉溶解细菌的丰富。我们的结果表明，酵母培养物补充剂似乎促进了一些特异性纤维消化细菌，同时降低了淀粉溶解细菌，这可能部分促进了更高的中性瘤胃pH值，更高的总VFA和异维。
J. Halfen[1][2];N. Carpinelli[1];F.A.B. Del Pino[2];J.D. Chapman[3];E.D. Sharman[3];J.L. Anderson[1];J.S. Osorio[1]. Effects of yeast culture supplementation on lactation performance and rumen fermentation profile and microbial abundance in mid-lactation Holstein dairy cows[J]. Journal of Dairy Science, 2021,104(11): 11580-11592