本试验旨在探讨饲粮中添加酵母硒对杜寒杂交羊生长性能、血常规和血清生化指标的影响。选用40只体重（34 kg左右）相近、健康状况良好的杜寒杂交断奶羔羊，随机分为4组，每组10只，进行单栏单只饲养。各组试验羊分别饲喂在基础饲粮中添加0（对照）、0.2、0.4和0.8 mg/kg的硒（硒的形式为酵母硒）的试验饲粮，对应的试验饲粮中硒含量的实测值分别为0.074（对照）、0.307、0.491和0.846 mg/kg。预试期10 d，正试期20 d。结果显示：随着硒添加量的增加，平均日增重呈先增加后降低的趋势，在硒添加量为0.2 mg/kg时平均日增重最大。当硒添加量为0.2 mg/kg时，杜寒杂交羊的料重比最低，极显著低于其他3个组（P<0.01）。当硒添加量为0.8 mg/kg时，血小板计数最高，极显著高于其他各组（P<0.01）。当硒添加量为0.8 mg/kg时，嗜碱性粒细胞百分数最高，极显著高于0.4 mg/kg组（P<0.01）。饲粮中添加不同水平的硒对其他血常规指标均无显著影响（P>0.05）。当硒添加量为0.8 mg/kg时，血清中总蛋白、尿素氮和肌酐含量均最高，显著或极显著高于其他各组（P<0.05或P<0.01）。0.8 mg/kg组血清中谷丙转氨酶和谷草转氨酶的活性最高，显著或极显著高于对照组（P<0.05或P<0.01）。对照组血清中碱性磷酸酶的活性最高，与0.2 mg/kg组差异不显著（P>0.05）。当硒添加量为0.8 mg/kg时，血清中γ-谷氨酰转移酶的活性最高，极显著高于其他各组（P<0.01）。当硒添加量为0.8 mg/kg时，血清中磷含量最高，极显著高于0.2和0.4 mg/kg组（P<0.01）。当硒添加量为0.8 mg/kg时，血清中铁含量最低，极显著低于对照组（P<0.01），同时0.4 mg/kg组血清中铁含量也极显著低于对照组（P<0.01）。综合本试验测定指标，杜寒杂交羊饲粮中酵母硒形式硒的适宜添加量为0.2 mg/kg（饲粮中硒含量的实测值为0.307 mg/kg）。

This experiment was conducted to study the effects of dietary selenium yeast on the growth performance, blood routine and serum biochemical indexes of Dorper×thin-tailed Han crossbred sheep. Forty Dorper×thin-tailed Han crossbred weaning lambs with the similar body weight (about 34 kg) and good health were randomly assigned to 4 groups with 10 sheep in each group, and all sheep were housed in individual pen. Sheep in the 4 groups were fed experimental diets supplemented with 0 (control), 0.2, 0.4 and 0.8 mg/kg selenium (the form was selenium yeast) based on a basal diet, and the measured values of the selenium content in the experimental diets were 0.074 (control), 0.307, 0.491 and 0.846 mg/kg, respectively. The experiment lasted for 10 days for adaption, and 20 days for test. The results showed as follows:average daily gain (ADG) was firstly increased and then decreased with selenium supplemental level increasing, and the highest value of ADG was found when selenium supplemental level was 0.2 mg/kg. The lowest value of feed/gain (F/G) was found when selenium supplemental level was 0.2 mg/kg, and it was significantly lower than that in the other three groups (P<0.01). The highest platelet count was found when selenium supplemental level was 0.8 mg/kg, and it had significant difference compared with the other three groups (P<0.01). The highest basophilic granulocytes (BASO) percentage was found when selenium supplemental level was 0.8 mg/kg, and it had significant difference compared with the 0.4 mg/kg group (P<0.01). Dietary supplemented with different levels of selenium had no significant effects on other blood routine indexes (P>0.05). The highest values of serum total protein (TP), urea nitrogen (UN) and creatinine (CREA) contents were found when selenium supplemental level was 0.8 mg/kg, and they had significant differences compared with the other groups (P<0.05 or P<0.01). The activities of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in 0.8 mg/kg group were the highest, which were significantly higher than those in the control group (P<0.05 or P<0.01). The serum alkaline phosphatase activity in control group had the highest value, and it had no significant difference compared with 0.2 mg/kg group (P>0.05). The highest value of serum γ-glutamyltransferase (γ-GGT) activity was found when selenium supplemental level was 0.8 mg/kg, and it had significant difference compared with the other groups (P<0.01). Phosphonium content in serum was the highest when selenium supplemental level was 0.8 mg/kg, and it had significant difference compared with 0.2 and 0.4 mg/kg groups (P<0.01). Iron content in serum was the lowest when selenium supplemental level was 0.8 mg/kg, which was significantly lower than that in control group (P<0.01), and it in 0.4 mg/kg group was also significantly lower than that in control group (P<0.01). Considering all indexes of this experiment, the appropriate selenium (the form is selenium yeast) supplemental level is 0.2 mg/kg in the diet of Dorper×thin-tailed Han crossbred sheep, and the measured value of selenium content in the diet is 0.307 mg/kg.