Effects Of Cysteine That Feeding The Fodder Containing Different Concentrations On The Daily Gains And The Slaughtering Performance And Meat Quality Of Tan×han Crossbreed Sheep

With the population growing in China and the improvement of per capita income level and living standards, the requirement of meat production and quality for people is growing gradually. In recent years, the state gradually had increased investment in agriculture for animal husbandry in particular, the animal husbandry developing rapidly. Mutton is a kind of important livestock product consumption in China, the consumption being the second only higher than pork and chicken. Through long-term breeding, mutton production increased year by year in our country, basically meeting the needs of residents for mutton. However, compared with that of the mutton production of developed countries, there is still a big gap between China and developed countries. Animal nutrition is one of the important factors which affect the animal growth and development. Therefore, mutton yield and quality can be improved through nutrition in the production practice. Cysteine is one of the most important nutrients in fodder, which has important influences on the animal growth and development.However, the effects of the cysteine on Tan×Han crossbieed sheep growth performance, blood biochemical index, carcass traits, muscle nutritional composition and physical indicators were not reported. In this study, different concentrations(0, 0.20%, 0.40% and 0.80%) rumen-protected cysteine was added in the fodder of hybrid sheep of Tan sheep and Small-tailed Han sheep. After 70 days feeding, these hybrid sheep growing performance, blood biochemical indicators, carcass shape, muscle nutrition composition and physical index after slaughtering were measured and anaylzed. The results were presented as following:1. The research results showed that compared with that of the control group, daily gains of the treatment groups were significant higher(P < 0.05), and the treatment group supplemented with 0.4% cysteine daily gain was the highest in all groups. The treatment groups had higher daily feed intakes and lower feed conversion rate(P > 0.5). Meanwhile, protein content of the treatment groups showed increased trend, the urea nitrogen and triglyceride levels having decreased trend, but no significant difference was observed among treatment groups(P > 0.5).2. The research results showed that feeding the fodder containing different concentrations of cysteine had different effects on the slaughtering performance of the hybrid mutton sheep. Treatment groups supplemented with 0.80% cysteine slaughter rate was significantly higher than that of the control group(P < 0.05). Saughter rate of other groups didn’t have significant difference compared with that of the control group(P > 0.05). The carcass weight was higher in treatment groups than that of the control group, but there was no significant difference(P > 0.05). The net meat percentage and eye muscle area in the treatment groups were higher than that of the control group(P < 0.05), and the treatment group added 0.40% cysteine group was the highest. The treatment groups didn’t have significant difference in the ratio of carcass bone weight to carcass weight compared with that of the control group(P > 0.05). The addition of cysteine in fodder, the ratios of subcutaneous fat, abdominal fat, tail fat and kidney fat respectively to carcass weight and the GR value were lower than that of the control group, but no significant differences was observed maong these groups(P > 0.05).3. The research results showed that after adding different concentration of cysteine in feed, all the sheep muscle glycogen, muscle protein and IMF contents were higher than the control group(P < 0.05). Meanwhile, the treatment group added 0.40% cysteine glycogen, protein and IMF contents were the highest in all groups. The muscle moisture and the cholesterol contents of the treatment groups had no significant difference compared with that of the control group(P > 0.05). Our results also suggested that mutton sheep muscle containing different kinds of fatty acids, palmitic acid, oleic acid and stearic acid possessed higher proportion in sheep muscle fatty acid. The fodder added different concentrations of cysteine, the effects of a variety of fatty acids content in sheep muscle were different. Adding different concentrations of cysteine in fodder improve the eye muscle chromatic aberration, but there was no significant difference between the treatment groups and the control group(P > 0.05). When adding 0.40% cysteine in fodder, the p H45 min value and cooking loss were significantly higher than that of other groups(P < 0.05). The drip losses in treatment groups were significantly lower than that of the control group. Meanwhile, the group with added 0.40% cysteine drip loss was the lowest in all groups(P < 0.05).In conclusion, adding a certain amount of rumen-protected cysteine in fodder improves the daily gain of mutton sheep, to promote growth. This could improve the slaughter rate, net meat percentage and eye muscle area, reducing the fat content and improving the carcass traits. That could increase the p H value and cooking loss, and improve the glycogen, protein and IMF contents in sheep muscle, reducing the drip loss and improving the meat quality.