Abstract：
Yeast and fibrolytic enzymes serve as additives incorporated into the nutrition of ruminants to regulate rumen fermentation and increase the digestibility of fiber, thereby enhancing the efficiency of rumen fermentation. Two experiments were conducted to assess the impact of five diets: a control diet without additives, diets with yeast (Saccharomyces cerevisiae) or exogenous fibrolytic enzymes (EFE), and diets with a blend of 0.7yeast + 0.3EFE or 0.7EFE + 0.3Yeast (based on recommended levels in g/kg of total DM). In the first experiment, 40 five-month-old Santa Ines lambs (mean weight 25.0 ± 1.3 kg) were distributed in a completely randomized design (5 treatments and 8 lambs) for 81 days to evaluate performance, ingestive behaviour, and serum metabolites. In the second experiment, 25 Santa Ines male lambs weighing 25.7 ± 4.1 kg were housed in metabolic cages, in a randomized design with 5 treatments and 5 lambs, evaluating digestibility, nitrogen balance, and rumen pH. EFE supplementation increased intakes of dry matter (DM), total digestible nutrients (TDN), and apNDF (mean of 38.1, 5.26, and 27%, respectively) compared to yeast or the 0.7yeast-0.3EFE blend. Feed conversion was most efficient (mean of 27.1%) in lambs fed Yeast, 0.7EFE + 0.3yeast, and the control diet. Lambs fed 0.7yeast + 0.3EFE spent less time eating (mean of 16.5%) and more time idling (mean of 10.75%), whereas EFE-fed lambs spent more time eating (mean of 19.73%), and 0.7EFE + 0.3yeast-fed lambs spent more time ruminating (mean of 20.14%). Control group lambs chewed and ruminated less (means of 24.64 and 17.21%, respectively) compared to other treatments. Lambs on the 0.7yeast + 0.3EFE blend had higher eating and rumination efficiency rates for DM and apNDF (mean of 19.11 and 17.95%, respectively) compared to other additive treatments or individual additives. They also exhibited lower (means 7.59 g/d) urinary N excretion, with improved N retention (mean 3185 g/d) compared to the control group. There were significant effects on serum albumin and cholesterol concentrations, with the 0.7yeast + 0.3EFE blend showing higher albumin (mean 4.08 g/dL) levels, while diets without additives and yeast-EFE blends had higher cholesterol (mean of 62.51 g/dL) concentrations. Including Saccharomyces cerevisiae yeast along with 0.7 yeast + 0.3 EFE blend is recommended when feeding similar lamb diets to those used herein because it improves the efficiency of intake, rumination of DM and NDF, and nitrogen utilization without affecting the lamb performance.
摘要：
酵母和纤维水解酶作为添加剂掺入反刍动物的营养，以调节瘤胃发酵和增加纤维的消化率，从而提高瘤胃发酵效率。进行了两个实验来评估五种饮食的影响：不含添加剂的对照饮食，酵母（酿酒酵母）或外源纤维裂解酶（EFE）的饮食，和含有0.7酵母+0.3EFE或0.7EFE+0.3酵母的混合饮食（基于推荐水平，以g/kg总DM为单位）。在第一个实验中,将40只五个月大的SantaInes羔羊（平均体重25.0±1.3kg）以完全随机设计（5种处理和8只羔羊）进行了81天的分配，以评估性能，摄食行为，和血清代谢物.在第二个实验中,25只体重25.7±4.1公斤的SantaInes雄性羔羊被安置在代谢笼中，在随机设计中，有5种治疗方法和5只羔羊，评估消化率，氮平衡，和瘤胃pH。EFE补充增加干物质（DM）的摄入量，总可消化营养素（TDN），和apNDF(平均值为38.1、5.26和27%，分别)与酵母或0.7酵母-0.3EFE混合物相比。饲喂酵母的羔羊饲料转化率最高(平均27.1%)，0.7EFE+0.3酵母，和控制饮食。饲喂0.7酵母+0.3EFE的羔羊进食时间较少（平均16.5%），空转时间较多（平均10.75%），而EFE喂养的羔羊花更多的时间吃（平均19.73%），和0.7EFE0.3酵母喂养的羔羊花更多的时间反刍动物（平均20.14％）。对照组羔羊咀嚼和反刍动物较少（平均24.64％和17.21％，分别)与其他治疗方法相比。0.7酵母0.3EFE混合物上的羔羊对DM和apNDF具有较高的进食效率和反刍动物效率（平均值分别为19.11和17.95％，分别)与其他添加剂处理或单个添加剂相比。他们还表现出更低的（平均7.59g/d）尿N排泄，与对照组相比，N保留率提高(平均3185g/d)。对血清白蛋白和胆固醇浓度有显著影响，0.7酵母+0.3EFE混合物显示更高的白蛋白水平（平均4.08g/dL），而不含添加剂和酵母-EFE混合物的饮食具有较高的胆固醇浓度（平均62.51g/dL）。当饲喂与本文所用相似的羊肉饮食时，推荐包括酿酒酵母酵母和0.7酵母+0.3EFE混合物，因为它提高了摄入效率，对DM和NDF的反思，在不影响羔羊生产性能的前提下对氮的利用。
