荞麦秸秆饲粮中添加甘露寡糖对滩羊生长性能、消化代谢、屠宰性能和肉品质的影响

Effects of Buckwheat Straw Diet Supplemented with Mannan Oligosaccharides on Growth Performance,Digestion and Metabolism,Slaughter Performance and Meat Quality of Tan Sheep

本试验在荞麦秸秆饲粮中添加不同水平的甘露寡糖(MOS),研究MOS对滩羊生长性能、消化代谢、屠宰性能和肉品质的影响,为其在滩羊生产中的应用提供参考。选择出生日期相近、体重相近且健康的3月龄宁夏滩羊断奶后羯羊20只,随机分为4组,每组5只,独笼饲养。对照组饲喂不添加MOS的基础饲粮,试验Ⅰ、Ⅱ、Ⅲ组分别在基础饲粮的基础上添加1.0%、2.0%、3.0%的MOS。基础饲粮精粗比为30∶70,粗饲料由荞麦秸秆和玉米青贮以40∶60的比例组成,其中荞麦秸秆经纤维素酶处理。预试期15 d,正试期60 d。结果显示:1)荞麦秸秆饲粮中添加不同水平的MOS对滩羊的干物质采食量、料重比、平均日增重均无显著影响(P>0.05),但试验组的平均日增重均高于对照组,以试验Ⅰ组的平均日增重最高,料重比最低。2)荞麦秸秆饲粮中添加不同水平MOS对酸性洗涤纤维(ADF)的表观消化率无显著影响(P>0.05),各试验组干物质(DM)和中性洗涤纤维(NDF)的表观消化率显著高于对照组(P<0.05)。3)进食氮、粪氮排出量、尿氮排出量、可消化氮、沉积氮、氮表观消化率各组间无显著差异(P>0.05);与对照组相比,各试验组总排出氮和氮利用率极显著降低(P<0.01),氮的生物学价值显著提高(P<0.05),以试验Ⅰ组的总排出氮最低,氮利用率、氮的生物学价值最高,分别为6.71 g/d、55.43%、85.40%。4)试验Ⅰ、Ⅱ组的眼肌面积与对照组相比显著增加(P<0.05);试验Ⅰ组的骨肉比最小,但各组间差异均不显著(P>0.05);试验Ⅱ组羊肉剪切力、滴水损失、黄度和亮度值较对照组显著或极显著降低(P<0.05或P<0.01),且该组熟肉率最高,达60.28%。综上可知,在荞麦秸秆饲粮中添加适量MOS可以提高滩羊的DM和NDF表观消化率,并能增加氮沉积,减少氮排放,提高氮利用率,还可以降低羊肉的剪切力、滴水损失、黄度和亮度值。本试验条件下,滩羊荞麦秸秆饲粮中MOS的适宜添加量为1.0%~2.0%。

By adding different levels of mannan oligosaccharides(MOS)into buckwheat straw diet,the effects of MOS on growth performance,digestion and metabolism,slaughter performance and meat quality of Tan sheep were studied in this experiment,and theoretical reference was provided for its application in Tan sheep production.Twenty healthy and three months old Ningxia Tan sheep with the similar date of birth and body weight were divided into 4 groups with 5 sheep per group,only alone the cage.Sheep in control group were fed a basal diet,while those in trial groupsⅠ,ⅡandⅢwere fed diets supplemented with 1.0%,2.0%and 3.0%MOS based on the basal diet,respectively.The forage⁃to⁃concentrate ratio of the basal diet was 30∶70,and the forage consisted of cellulase⁃treated buckwheat straw and alfalfa in a ratio of 40∶60.The pre⁃feeding period was 15 days,and the trial period was 60 days.The results showed as follows:1)buckwheat straw diet supplemented with different levels of mannan oligosaccharides had no significant effects on dry mat⁃ter intake,feed/gain and average daily gain of Tan sheep(P>0.05),but the average daily gain of the trial groups was higher than that of the control group,and the highest average daily gain and the lowest feed/gain were found in trial groupⅠ.2)Buckwheat straw diet supplemented with different levels of mannan oligosac⁃charides had no significant effect on the apparent digestibility of acid detergent fiber(ADF)of Tan sheep(P>0.05),but the apparent digestibility of dry matter(DM)and neutral detergent fiber(NDF)in the trial groups was significantly higher than that in the control group(P<0.05).3)There were no significant differences in the nitrogen intake,fecal nitrogen output,urine nitrogen output,digestible nitrogen,nitrogen deposition and nitrogen apparent digestibility among groups(P>0.05).Compared with the control group,the total nitrogen output and nitrogen utilization rate of the trial groups were significantly reduced(P<0.01),and the biological value of nitrogen was significantly improved(P<0.05).The total nitrogen output was the lowest,and the ni⁃trogen utilization rate and the biological value of nitrogen were the highest in the trial groupⅠ,and the values of them were 6.71 g/d,55.43%and 85.40%,respectively.4)The eye muscle area of trial groupsⅠandⅡwas significantly improved(P<0.05).The bone to meat ratio was the lowest in the trial groupⅠ,but the difference was not significant among groups(P>0.05).The shear force,drip loss,yellowness and brightness values of the trial groupⅡwere significantly lower than those of the control group(P<0.05 or P<0.01),and the cooked meat rate of the trial groupⅡwas the highest,which up to 60.28%.In summary,buckwheat straw diet supplemented with appropriate amount of MOS can increase the apparent digestibility of DM and NDF,in⁃crease the nitrogen deposition,reduce the nitrogen emission,increase the nitrogen utilization,and can decrease the shear force,drip loss,yellowness and brightness values of mutton of Tan sheep.The optimum addition a⁃mount of MOS in buckwheat straw diet of Tan sheep under the experimental conditions is 1.0%to 2.0%.