摘要
The study objective was to investigate the effects of site of delivering Saccharomyces cerevisiae fermentation product (SCFP) on ruminal pH and fermentation characteristics, and the site and extent of feed digestion in the digestive tract of beef heifers fed high-grain diets. Examining the ruminal and postruminal effects of SCFP is important for understanding the potential use of SCFP as an alternative for current industry-standard antibiotics used in beef cattle rations. Five beef heifers (initial BW = 561 ± 11.7 kg) equipped with ruminal and duodenal cannulas were used in a 5 × 5 Latin square design with 28-d periods, including 21 d for adaption and 7 d for data collection. Five treatments were as follows: 1) control diet that contained 10% barley silage and 90% barley concentrate mix (DM basis); 2) control diet supplemented with antibiotics (ANT; 330-mg monensin/d and 110-mg tylosin/d per head); 3) ruminal (top dress) delivery of SCFP (rSCFP; NaturSafe, Diamond V, 18-g SCFP/d); 4) duodenal delivery of SCFP (dSCFP; 18-g SCFP/d, via duodenal cannula); and 5) a combination of rSCFP and dSCFP (rdSCFP; 18-g rSCFP and 18-g dSCFP). Intake of DM tended (P < 0.10) to be greater by heifers fed rdSCFP than those fed control, ANT and rSCFP diets. Minimum ruminal pH was greater (P < 0.05) with rSCFP than control and rdSCFP treatments. The duration of ruminal pH < 5.6 tended (P < 0.10) to be less with rSCFP than control and ANT. Heifers fed the rSCFP diet had greater (P < 0.03) protozoa counts and proportion of acetate than the other treatments. Nutrient flows to the duodenum did not differ (P > 0.19), whereas the amount of truly fermented OM was greater (P < 0.03) with rdSCFP than the other treatments. Ruminal OM digestibility was highest with rSCFP and rdSCFP, intermediate with dSCFP and ANT, and lowest with control (P < 0.03). Intestinal digestibility was similar among treatments. As a result, total tract digestibility of OM (P < 0.07) and NDF (P < 0.01) was greater with rSCFP and rdSCFP than control and ANT. Fecal IgA concentration was highest with ANT, intermediate with dSCFP and rdSCFP, and lowest with control and rSCFP (P < 0.03). These results demonstrate that feeding SCFP improved stability of ruminal pH and digestibility of OM and NDF. Delivery of SCFP to the duodenum appeared to have little effect on nutrient digestibility but improved intestinal immune response. Feeding SCFP performed better or at least equal to antibiotics currently used in beef cattle rations and could be a natural alternative for beef cattle production.
摘要译文
研究目的是研究酿酒酵母发酵产物（SCFP）的位点对瘤胃pH和发酵特性的影响，以及饲喂高谷物饲料的牛仔母牛消化道中饲料消化的部位和程度。检查SCFP的瘤胃和后位效应对于了解SCFP作为肉牛日粮中使用的当前行业标准抗生素的替代品的潜在用途非常重要。配备有瘤胃和十二指肠插管的五头牛小母牛（初始BW \x3d 561±11.7千克）用于5×5拉丁方设计，周期为28天，包括21 d用于适应，7 d用于数据收集。五种处理如下：1）对照饮食，其含有10％大麦青贮饲料和90％大麦浓缩物混合物（基于DM）;2）控制饮食补充抗生素（ANT; 330 mg莫能菌素/ d和每头110 mg泰乐菌素/ d）; 3）瘤胃（top dress）递送SCFP（rSCFP; NaturSafe，Diamond V，18-g SCFP / d）;4）十二指肠输送SCFP（dSCFP; 18-g SCFP / d，通过十二指肠插管）; 5）rSCFP和dSCFP的组合（rdSCFP; 18-g rSCFP和18-g dSCFP）。摄入DM倾向（P 0。10）喂养rdSCFP的小母牛比饲喂对照，ANT和rSCFP饮食更大。与对照和rdSCFP处理相比，rSCFP的最低瘤胃pH值更高（P 0.05）。与对照和ANT相比，rSCFP的瘤胃pH 5.6的持续时间（P 0.10）更低。喂食rSCFP饮食的小母牛有更大的（P 0。03）原生动物计数和醋酸盐比例比其他处理。流向十二指肠的营养物质没有差异（P 0.19），而真正发酵的OM的量则更大（P 0。03）用rdSCFP比其他治疗方法。 rSCFP和rdSCFP的Ruminal OM消化率最高，dSCFP和ANT的中间消化率最高，对照组的消化率最低（P 0.03）。治疗期间肠道消化率相似。因此，rSCFP和rdSCFP比对照和ANT的OM（P 0.07）和NDF（P 0.01）的总消化道消化率更高。ANT的粪便IgA浓度最高，dSCFP和rdSCFP的中间体浓度最高，对照和rSCFP的浓度最低（P 0.03）。这些结果表明饲喂SCFP改善了瘤胃pH的稳定性和OM和NDF的消化率。将SCFP递送至十二指肠似乎对营养物消化率几乎没有影响，但改善了肠道免疫应答。饲喂SCFP比目前在肉牛日粮中使用的抗生素表现更好或至少相当，并且可以成为肉牛生产的天然替代品。
Yizhao Shen;Hongrong Wang;Tao Ran;Ilkyu Yoon;Atef Mohamed Saleem;Wenzhu Yang. Influence of yeast culture and feed antibiotics on ruminal fermentation and site and extent of digestion in beef heifers fed high grain rations[J]. Journal of Animal Science, 2018,96(9): 3916–3927