2～3月龄肉兔日粮消化能水平对消化代谢和产肉性能影响的研究

EFFECTS OF DIGESTIBLE ENERGY LEVELS ON DIGESTIBILITY,METABOLISM AND MEAT QUALITY OF 2～3 MONTHS MEAT RABBITS

选用50只2月龄新西兰兔分成5组,饲喂5种消化能(DE,MJ/kg)水平的日粮(分别为9.46、10.46、11.46、12.46和13.46),测定了日粮消化能水平对2～3月龄新西兰兔生产性能、营养物质消化利用、免疫指标、小肠酶活性、盲肠内环境和肉质的影响。结果表明:日粮能量水平对日增重、料肉比影响显著(P<0.05),日增重以10.46MJ/kg组最大,为29.28g,料肉比随能量水平升高而降低;日粮能量水平对试验兔除灰分消化率外都有显著影响(P<0.05),粗蛋白(CP)消化率、氮沉积以10.46MJ/kg组最大,粗纤维(CF)和能量消化率随日粮能量水平升高而升高,脂肪和灰分消化率则随日粮能量水平升高而降低;能量水平对3月龄肉兔免疫指标影响不显著;小肠淀粉酶和脂肪酶活性随能量水平升高而增加(P<0.05);3月龄试兔盲肠内pH值、NH3-N浓度、丙酸比例和丁酸比例均随日粮能量水平升高而增加,总挥发性脂肪酸浓度(TVFA)、乙酸比例、乙丙酸比则随日粮能量水平升高而减少,其中能量水平对pH值、NH3-N含量、丁酸比例、乙酸比例的影响显著(P<0.05),而对丙酸比例、TVFA和乙、丙酸比影响极显著(P<0.01);能量水平对3月龄肉兔半净膛、全净膛屠宰率无显著影响(P>0.05),对屠体重、全净膛重、眼肌面积影响显著(P<0.05),其中屠体重以10.46MJ/kg组最高;能量水平对肉兔背最?

An experiment was conducted to determine the effect of varying levels of dietary digestible energy(DE) on growing development,nutrient utilization,small intestine digestive enzyme activity,immunity index,caecum fermentation and meat quality of 2～3 months New Zealand rabbits.Fitfty 2-month rabbits were allocated in individual cages for five treatments in which they were fed each diet with different DE levels(9.46MJ/kg,10.46MJ/kg,11.46MJ/kg,12.46MJ/kg and 13.46MJ/kg,respectively).The results showed as follows:DE level had significantly influence on average daily gain(ADG)and feed conversion ratio (FCR) P<0.05),ADG was the largest(29.28g) when dietary DE was 10.46MJ/kg;FCR raised when dietary DE increased.Dietary DE level affect nutrient (except ash)digestibilities significantly(P<0.05),the digestiblity of CP and nitrogen retention(RN) were the largest when dietary DE was 10.46MJ/kg,the digestibility of CF and energy raised with dietary DE level increased,then the digestibility of fat and ash reduced when dietary DE increased.Dietary DE level had not significant influence on immunity index(P<0.05),the amylase activity and lipase activity of the small intestine increased when dietary DE level raised(P<0.05).The differences of pH value?NH3-N concentration?acetic acid and butyric acid concentrations in different treatments were significant(P<0.05),TVFA propionic acid concentrations and the ratio of acetic acid to propionic acid in different treatments were significant(P<0.01),dietary DE level had not significant influence on carcass percentage(P>0.05),but had significant influence on empty body weight,total eviscerating weight and longissimus dorsi area(P<0.05).The physical traits?protein and ash contents in meat had not significant difference(P>0.05)among different treatments;moisture and fat contents had sigificant difference(P<0.05),and the fat content of meat increased with dietary DE level raised.Dietary DE level had no significant influence on tetradecnic acid?palmiltic acid and palmitoleic acid content of meat(P>0.05);stearic acid?oleic acid and linoleic acid content in the meat increased when dietary DE level raised(P<0.05).According to ADG,FCR,RN indexes, the appropriate dietary DE level for 2～3 month rabbits was 10.46MJ/kg.