本试验旨在研究沙葱黄酮对肉羊生产性能和肠道组织免疫因子β-防御素-1（sBD-1）和β-防御素-2（sBD-2）基因表达的影响。选取60只健康、体重[（39.9±3.2）kg]相近的6月龄小尾寒羊羯羊，采用单因素完全随机区组设计，共分为4组，每组15只。对照组饲喂基础饲粮，试验组分别饲喂在基础饲粮中添加11（低浓度黄酮组）、22（中浓度黄酮组）和33 mg/kg沙葱黄酮（高浓度黄酮组）的试验饲粮，共饲喂70 d，其中预试期15 d，正试期60 d。每天记录各组羊的采食量，每隔15 d晨饲前空腹称重1次。试验结束后每组随机选取3只羊进行屠宰，采集十二指肠、空肠、回肠组织样，应用实时荧光定量PCR进行sBD-1和sB-2基因相对表达量的测定。结果表明：1）试验第30~45天以及第45~60天，各试验组肉羊的平均日采食量均显著高于对照组（P<0.05），其中以高浓度黄酮组肉羊的平均日采食量最高；试验第45~60天，与对照组相比，各试验组肉羊的平均日增重显著提高（P<0.05），料重比显著降低（P<0.05），其中以中浓度黄酮组肉羊的平均日增重最高，高浓度黄酮组料重比最低。2）与对照组相比，饲粮添加33 mg/kg的沙葱黄酮显著提高了sBD-1基因在空肠和回肠中及sBD-2基因在空肠中的相对表达量（P<0.05），饲粮添加22 mg/kg的沙葱黄酮显著提高了sBD-2基因在十二指肠中的相对表达量（P<0.05）。综上所述，饲粮中添加22~33 mg/kg的沙葱黄酮能够显著提高肉羊生产性能和β-防御素（sBD-1、sBD-2）基因在肠道组织中的表达。

The objective of this study was to investigate the effects of Allium mongolicum Regel flavonoids on performance and the expression of immune factors-β-defensin 1 (sBD-1) and β-defensin 2 (sBD-2) in intestinal tissue of meat sheep. Single factor completely randomized block design was used in the current study, a total of 60 healthy and six-month-old thin-tailed Han wethers with similar body weight[(39.9±3.2) kg] were randomly divided into 4 groups with 15 sheep each. Sheep in control group were fed a basal diet, and those in experimental groups were fed the basal diet supplemented with 11 (low-dose flavonoids group), 22 (mid-dose flavonoids group) and 33 mg/kg Allium mongolicum Regel flavonoids (high-dose flavonoids group), respectively. The trial period lasted for 75 d, which consisted of 15 d of pre-feeding period and 60 d of formal period. Intake was recorded every day and sheep were weighted before feeding every 15 d. At the end of the experiment, three sheep were randomly selected from each group and slaughtered to collect the duodenum, jejunum and ileum tissues. The relative expression levels of genes involved in sBD-1 and sBD-2 were measured by real time-qPCR. The results showed as follows:1) at the 30th to 45th day of experiment, the average daily feed intake of meat sheep in experimental groups was significantly higher than that in control group (P<0.05), and the highest average daily feed intake was found in high-dose flavonoids group. At the 45th to 60th day of experiment, the average daily gain was significantly increased and the feed to gain ratio was significantly decreased in experimental groups compared with the control group (P<0.05), and the highest average daily gain and the lowest feed to gain ratio were found in mid-dose flavonoids group and high-dose flavonoids group, respectively. 2) Compared with the control group, diet supplemented with 33 mg/kg Allium mongolicum Regel flavonoids significantly increased the relative expression levels of sBD-1 gene in jejunum and ileum and sBD-2 gene in jejunum (P<0.05), and diet supplemented with 22 mg/kg Allium mongolicum Regel flavonoids significantly increased the relative expression levels of sBD-2 gene in duodenum (P<0.05). In conclusion, diet supplemented with 33 mg/kg Allium mongolicum Regel flavonoids can significantly increase the performance and the expression of β-defensins (sBD-1 and sBD-2) genes in intestine of meat sheep.