目的 研究基础日粮中添加不同水平酵母培养物对育肥羊生长性能和免疫指标的影响，寻求具有促生长作用的替抗产品。 方法 选用160只体格健壮、体质量（40±2） kg的3~4月龄的育肥公羊作为研究对象，采用随机数字表法分为4组，分别饲喂在基础日粮中添加0%（对照组）、0.3%（低剂量组）、0.6%（中剂量组）和0.9%（高剂量组）酵母培养物的试验饲粮，试验期90 d。分别测定育肥羊的平均日采食量、平均日增质量和料重比，并对育肥羊静脉血清中的IgG、IgA和IgM含量进行测定。 结果 与对照组相比，3个试验组育肥羊平均日增质量和平均日采食量显著升高，料重比显著降低，静脉血清中IgG、IgA和IgM含量显著提高，其中，添加0.6%酵母培养物的试验组育肥羊平均日增质量为176.56 g，血清中IgG、IgA和IgM含量分别为29.25、191.25、2 165.49 μg/mL。 结论 饲粮中添加酵母培养物在一定程度上改善育肥羊的生长性能，提高育肥羊的免疫能力，添加0.6%酵母培养物的效果为佳。

Objectives The effects of adding different levels of yeast culture to the basic diet on the growth performance and immune indexes of fattening sheep were studied to provide reference for seeking products instead of antibodies with effects of promoting growth. Methods 160 healthy fattening rams aged 3-4 months with a body weight of (40±2) kg were selected and randomly divided into 4 groups using a random number table method. They were fed with experimental diets supplemented with 0(control group), 0.3%(low dose group), 0.6%(medium dose group), and 0.9%(high dose group) yeast culture in the basic diet for 90 days. The average daily intake of feed, average daily gain of weight, and the ratio of feed to weight in fattening sheep were determined. The content of IgG, IgA, and IgM in the venous serum of fattening sheep were measured as well. Results Compared with the control group, the average daily intake of feed, average daily gain of weight of fattening sheep in the low dose, medium dose, and high dose groups significantly increased, while the ratio of feed to weight significantly decreased. The content of IgG, IgA, and IgM in the venous serum of fattening sheep in the low dose, medium dose, and high dose groups significantly increased. Among them, the experimental group with 0.6% yeast culture added had an average daily gain of weight of 176.56 g for fattening sheep, and the content of IgG, IgA, and IgM in the venous serum of fattening sheep was 29.25, 191.25, and 2 165.49 μg/mL, respectively. Conclusions Adding yeast culture to the diet can improve the growth performance and enhance the immune capacity of fattening sheep to a certain extent, with the best effect of adding 0.6% yeast culture to the diet.