本试验将饲粮精粗比设为30∶70，并将苜蓿与复合化学处理稻草以40∶60组合作为粗饲料，研究复合化学处理稻草饲粮中添加过瘤胃蛋氨酸对舍饲滩羊生长性能、屠宰性能和肉品质的影响。选取4月龄、平均体重为20.54 kg的健康无疾病的滩羊羯羊20只，随机分为5组，每组4只，对照组饲喂基础饲粮，试验Ⅰ、Ⅱ、Ⅲ和Ⅳ组在基础饲粮中分别添加1.5、3.0、4.5和6.0 g/（d·只）过瘤胃蛋氨酸，进行饲养试验，预试期15 d，正试期60 d。于试验第1天测定试验羊只的初始体重，记录试验期间每日采食量，饲养试验结束当天测定试验羊只的终末体重。屠宰试验于饲养试验结束后的第2天进行，试验羊屠宰后剥离胴体，现场测定羊肉理化指标，并采集肉样进行常规营养成分分析。结果显示：1）与对照组相比，饲粮中添加过瘤胃蛋氨酸对舍饲滩羊总增重和平均日增重均无显著影响（P>0.05），但以试验Ⅲ组的总增重和平均日增重最高。各试验组的料重比均低于对照组（P>0.05），且以试验Ⅲ组的料重比最低。2）在屠宰性能方面，各组宰前活重、胴体重、屠宰率无显著差异（P>0.05）。试验Ⅲ组的净肉率显著高于对照组（P<0.05），与其他试验组无显著差异（P>0.05）。3）在羊肉理化指标方面，试验Ⅲ组羊肉滴水损失显著低于对照组（P<0.05），熟肉率显著高于对照组（P<0.05），与其他各试验组无显著差异（P>0.05）；各组羊肉剪切力无显著差异（P>0.05），但以试验Ⅲ组的剪切力最低。4）在羊肉常规营养成分方面，各试验组羊肉粗蛋白质含量均显著高于对照组（P<0.05），粗脂肪含量均显著低于对照组（P<0.05），水分与粗灰分含量与对照组无显著差异（P>0.05）。由此得出，在饲粮中添加过瘤胃蛋氨酸可在一定程度上提高舍饲滩羊的增重、胴体净肉率和肉品质，且当过瘤胃蛋氨酸添加量为4.5 g/（d·只）时效果最好。

This experiment was conducted to determine the effects of rumen-protected methionine (RPMet) on the growth performance, slaughter performance and meat quality of house-feeding Tan sheep fed complex chemical treatment straw diets (diet forage-to-concentrate ratio was 70:30, and the forage was composed of 40% alfalfa and 60% complex chemical treatment straw). Twenty healthy Tan sheep (4-month-old, average body weight of 20.54 kg) were randomly divided into 5 groups with 4 sheep in each group. The sheep in control group were fed a basal diet, while the sheep in trail groupsⅠ, Ⅱ, Ⅲ and Ⅳ were fed the basal diets added 1.5, 3.0, 4.5 and 6.0 g/d RPMet for every sheep, respectively. The preparation period was 15 days, and the formal experiment period was 60 days. Measured the initial weight at the first day and the final weight at the end day of experiment, besides, recorded daily intake during experiment. Slaughtering experiment was carried out on the second day after the end of feeding experiment. The carcasses of sheep were stripped off after slaughtering. Measured the physicochemical indexes of mutton, and collected the meat samples for common nutrition components analysis. The results showed as follows:1) compared with the control group, diets supplemented with RPMet had no significant effect on average daily gain and total gain (P>0.05), but the trial group Ⅲ had the highest average daily gain and total gain among all groups (P>0.05). The feed/gain of control group was lower than that of other groups, and trial group Ⅲ had the lowest feed/gain in all groups. 2) For slaughter performance, there was no significant difference among the groups in live weight before slaughter, carcass weight and dressing percentage (P>0.05). The net meat percentage of trial group Ⅲ was significantly higher than that of control group (P<0.05), and it had no significant difference with other groups (P>0.05). 3) For mutton physicochemical properties, the drip loss of trial group Ⅲ was significantly lower than that of control group (P<0.05), and the cooked meat percentage was significantly higher than that of control group (P<0.05), but there was no significant difference among all trial groups (P>0.05). The shearing force of trial group Ⅲ was the lowest, and there was no significant difference among all groups (P>0.05). 4) For mutton common nutrition components, the content of crude protein in mutton for each trial group was significantly higher than that of control group (P<0.05), and the content of ether extract in mutton for each trial group was significantly lower than that of control group (P<0.05). There was no significant difference in the contents of moisture and ash among all groups (P>0.05). Therefore, RPMet supplementation into complex chemical treatment straw diets can improve the gain, carcass net meat percentage and meat quality of house-feeding Tan sheep to some extents, and the addition of 4.5 g/(d·sheep) is the best.