日粮ADF水平对2-3月龄肉兔生产性能、消化酶活性和盲肠发酵的影响

EFFECTS OF DIFFERENT ADF LEVELS ON SMALL INTESTINE DIGESTIVE ENZYME ACTIVITY,CAECAL FERMENTATION AND GROWTH PERF ORMANCE OF 2-3 MONTH MEAT RABBITS ABSTRACT

选用60只2月龄新西兰肉兔，随机分成5组，分别饲喂5种酸性洗涤纤维（ADF）水平的日粮（分别为13%、16%、19%、22%和25%），测定了日粮ADF水平对2-3月龄新西兰肉兔小肠消化酶活性、盲肠纤维素酶活性、盲肠内环境及生产性能的影响。结果表明：日粮ADF水平对试兔小肠淀粉酶活性影响显著（P〈0.05），对胰蛋白酶和胰凝乳蛋白酶活性影响不显著（P〉0.05），但随ADF水平升高胰蛋白酶和胰凝乳蛋白酶活性有先增加后降低的趋势。盲肠纤维素酶活性随ADF水平升高显著增加（P〈0.05）。日粮ADF水平对3月龄试兔盲肠总挥发性脂肪酸（TVFA）浓度和丙酸比例影响不显著（P〉0.05），但对丁酸比例影响显著（P〈0.05）。同时，盲肠pH值、乙酸比例及乙丁酸比均随日粮ADF水平升高而增加（P〈0.05），NH3-N浓度则随ADF水平升高而降低（P〈0.05）。试兔平均日增重、平均日采食量及料重比均受日粮ADF水平显著影响（P〈0.05），随ADF水平的升高，平均日采食量增加、料重比先降低后增加，而平均日增重则先增加后降低，以19%处理组最大，为29.53 g。综合以上研究结果，以平均日增重和料重比为主要经济指标，2-3月龄肉兔适宜的ADF水平为16%-19%.

An experiment was conducted to determine the effect of varying levels of dietary acid detergent fibre （ADF） on small intestine digestive enzyme activity, caecal cellulase activity, caecal fermentation and growth performance of 2-3 month New Zealand rabbits. Sixty 2 -month rabbits were allocated in individual cages for five treatments in which they were fed each diet with different ADF levels（ 13% ,16% ,19% ,22% and 25%, respectively）. The results showed as follows： ADF level had significant influence on the amylase activity of the small intestine （P 〈 0.05） ;The Trypsin activity and the Chymotrysin activity increased firstly and then decreased slowly with ADF level increased, but the differences in different treatments were not significant （p 〉 0. 05 ） . Caecal cellulase activity raised significantly when dietary ADF level increased （p 〈0. 05 ）. ADF levels had no significant effects on caecal total volatile fatty acids （TVFA） concentration and propionate proportion of 3 -month old trial rabbits （p 〉0.05）, but the butyrate proportion was affected significantly （p 〈0.05 ）. Meanwhile , the differences of caecal pH value, acetate proportion and the ratio of acetate to butyrate in different treatments were significant （p 〈0.05） and all increased with ADF level raised, conversely, NH3- N concentration reduced when dietary ADF level raised （p 〈0.05 ）. Average daily gain （ADG） , average daily feed intake （ADFI） and feed conversion ratio （rCR） of trial rabbits were all affected by dietary ADF levels significantly （p 〈0.05）. When ADF level increased, ADF I raised ,FCR decreased firstly and then raised, but ADG raised firstly and then reduced with ADF level increased and it was the largest （29.53 g） when dietary ADF was 19%. According to ADG and FCR indexes, the appropriate dietary ADF level for 2 - 3 month meat rabbits was 16% - 19%.