Effects Of Compound Nutrients On Weight Gain,Slaughter Performance And Meat Quality Of Fattening Small Tail Han Sheep

With the increase in people’s demand for high-quality mutton and the promulgation of the national ban on the use of antibiotics in livestock and poultry breeding,the research on plant extracts in the livestock industry is becoming more and more extensive and in-depth.so,In this thesis,the effects of compound nutrients（composed of fermented bran polysaccharide,eugenol,cinnamaldehyde and chili oil resin）on weight gain,slaughter performance and meat quality of Small Tail Han sheep fattening sheep were studied by two experimental systems.Sixteen Small Tailed Han sheep ewes aged from 3 to 4 months with similar body weight（24.18±0.31kg）and good health were randomly divided into two groups,with 8 ewes in each group.The control group was fed with basal diet without adding compound nutrients,and the experimental group was fed with basal diet supplemented with 3‰compound nutrients.The experimental period was 97 d,including the pretest period of 7 d and the formal period of 90 d,which was divided into the former（0～30 d）,the middle（31～60 d）and the later（61～90 d）.This thesis mainly includes two experiments.Experiment 1:Effects of dietary compound nutrients on weight gain,rumen fermentation parameters and blood indexes of fattening sheep.The results showed that:1)Compared with the control group,the final weight and average daily gain（ADG）of fattening sheep in the experimental group were higher than those in the control group,and in the middle of the experiment,the ADG of fattening sheep in the experimental group was significantly higher than that in the control group（P<0.05）.2)Compared with the control group,the addition of compound nutrients in the diet significantly reduced the ammonia nitrogen（NH₃-N）concentration and protozoa number in the rumen of fattening sheep in the experimental group（P<0.05）.3)Compared with the control group,in the middle of the experiment,the contents of immunoglobulin G（Ig G）（P=0.07）and interleukin-1β（IL-1β）in the serum of fattening sheep in the experimental group showed an increasing trend（P=0.05）.At the end of the experiment,the addition of compound nutrients in the diet significantly increased the Ig G content of fattening sheep in the experimental group（P<0.05）,and the content of interleukin-17（IL-17）decreased（P=0.06）.4)Compared with the control group,the activities of superoxide dismutase（SOD）and glutathione peroxidase（GSH-Px）in serum of fattening sheep in the experimental group were significantly increased by adding compound nutrients in the diet at the early stage of the experiment（P<0.05）,and the content of malondialdehyde（MDA）showed a decreasing trend（P=0.08）.In the middle of the experiment,the activity of SOD in fattening sheep was significantly increased（P<0.05）.At the end of the experiment,the activities of SOD,GSH-Px,catalase（CAT）and total antioxidant capacity（T-AOC）in serum of fattening sheep in the experimental group were significantly increased by adding compound nutrients in the diet（P<0.05）.Experiment 2:Effects of compound nutrients on slaughter performance,meat quality and muscle antioxidant indexes of fattening Small Tail Han sheep.The results showed that:1)Compared with the control group,the addition of compound nutrients in the diet significantly increased the area of eye muscle of fattening sheep in the experimental group（P<0.05）,and the live weight before slaughter showed an increasing trend（P=0.07）.2)Compared with the control group,the yellowness（b*）of the fattening sheep in the experimental group was significantly decreased（P<0.05）,and the brightness（L*）showed a decreasing trend（P=0.08）.3)The addition of compound nutrients in the diet could significantly increase the contents of crude protein（CP）and crude ash（Ash）in the conventional nutrients of the longissimus dorsi muscle of the fattening sheep in the experimental group（P>0.05）.4)The addition of compound nutrients in the diet significantly increased the proportion of threonine（Thr）and serine（Ser）in the longissimus dorsi muscle of the fattening sheep in the experimental group（P<0.05）,and significantly decreased the proportion of complexine（Tyr）and essential amino acid（EAA）（P<0.05）.In summary,the addition of 3‰compound nutrients in diets improved the meat production performance of mutton sheep.The rumen fermentation parameters were optimized;improve the immune and antioxidant capacity of mutton sheep;improving meat quality.