饲粮能量水平对肉驴生长育肥性能和屠宰性能的影响

Effects of Dietary Energy Level on Growth-Fattening Performance and Slaughter Performance of Meat Donkeys

本试验旨在研究饲粮能量水平对肉驴生长育肥性能和屠宰性能的影响,为舍饲肉驴营养需要的制定提供理论基础。采用单因子完全随机试验设计,将36头年龄为1岁、体重[(150±25)kg]相近的肉驴(公),随机分为3组(E1、E2和E3组),每个组设4个重复,每个重复3头驴。E1组饲喂低能量水平饲粮,育肥前期(1~45 d)、中期(46~90 d)和后期(91~135 d)饲粮消化能水平分别为10.13、11.23和11.97 MJ/kg;E2组饲喂中能量水平饲粮,育肥前期、中期和后期饲粮消化能水平分别为11.14、12.02和12.82 MJ/kg;E3组饲喂高能量水平饲粮,育肥前期、中期和后期饲粮消化能水平分别为11.49、12.44和13.22 MJ/kg。结果显示:E2组在育肥中期和后期的体重、平均日增重均显著高于E1和E3组(育肥后期的平均日增重除外)(P<0.05),料重比显著低于E1和E3组(P<0.05);整个试验期的平均日增重表现为E2组>E3组>E1组,且组间差异显著(P<0.05)。宰前活重和胴体重表现为E2组>E3组>E1组,且组间差异显著(P<0.05),但E3组的肉骨比和眼肌面积分别显著(P<0.05)和趋于显著(0.05≤P<0.10)低于E1和E2组;E3组的大网膜脂肪重、肠系膜脂肪重、肾周脂肪重和腹内脂肪重以及GR值显著高于E1组(P<0.05),E2组显著高于E1组(大网膜脂肪重除外)(P<0.05)。E3组肺脏重显著高于E1和E2组(P<0.05);与E2组相比,E1和E3组总脏器指数有升高的趋势(0.05≤P<0.10),消化道总重和回肠重、消化道总长度显著降低(P<0.05),空肠、直肠和整个消化道指数以及直肠重显著升高(P<0.05)。综上可知,在育肥前期、中期和后期饲粮消化能水平分别为11.23、12.02和12.44 MJ/kg时,肉驴可获得较好的生长育肥性能与屠宰性能;饲粮能量水平过高或过低均不利于肉驴生长育肥性能与屠宰性能的发挥。

This study mainly investigated the effects of dietary energy level on the growth-fattening performance and slaughter performance of meat donkeys,and provided a theoretical basis for the formulation of nutrient requirements of stall-feeding meat donkeys.Using a single-factor completed random design,thirty-six meat donkeys(male)aged 1 years with similar body weight[(150±25)kg]were selected and randomly divided into 3 groups(E1,E2 and E3 groups)with 4 replicates in each group,and 3 donkeys in each replicate.Donkeys in the E1 group were fed low-energy level diets,and the digestible energy levels in the diets at the early fattening period(1 to 45 d),middle fattening period(46 to 90 d)and late fattening period(91 to 135 d)were 10.13,11.23 and 11.97 MJ/kg,respectively;donkeys in the E2 group were fed middle-energy level diets,and the digestible energy levels in the diets at early fattening period,middle fattening period and late fattening period were 11.14,12.02 and 12.82 MJ/kg,respectively;donkeys in the E3 group were fed high-energy level diets,and the digestible energy levels in the diets at the early fattening period,middle fattening period and late fattening period were 11.49,12.44 and 13.22 MJ/kg,respectively.The results showed that the body weight,average daily gain of E2 group were significantly higher than those of E1 and E3 groups(except for average daily gain at the late fattening period)(P<0.05),and the feed to gain ratio was significantly higher than that of E1 and E3 groups at the middle fattening period and the late fattening period(P<0.05).The average daily gain was E2 group>E3 group>E1 group in the whole trial period,and the differences were significant among groups(P<0.05).The live weight before slaughter and carcass weight were E2 group>E3 group>E1 group,and the differences were significant among groups(P<0.05),but the meat to bone ratio and eye muscle area of E3 group were significantly(P<0.05)or tended to be significantly(0.05≤P<0.10)lower than those of E1 and E2 groups,respectively;the omental fat weight,mesenteric fat weight,perirenal fat weight,intra-abdominal fat weight and GR value of group E3 were significantly higher than those of E1 group(P<0.05),and those(except omental fat weight)of E2 group were significantly higher than those of E1 group(P<0.05).The lung weight of E3 group was significantly higher than that of E1 and E2 groups(P<0.05).Compared with E2 group,the index of whole visceral organ of E1 and E3 groups trended to significantly increase(0.05≤P<0.10),the whole digestive tract weight,ileal weight and whole digestive tract length significantly decreased(P<0.05),and the indexes of jejunum,rectum and whole digestive tract weight and rectal weight significantly increased(P<0.05).In summary,meat donkeys can obtain the better growth-fattening performance and slaughter performance when the dietary digestible energy levels at the early fattening period,middle fattening period and late fattening period are 11.23,12.02 and 12.44 MJ/kg,respectively.When dietary energy levels are too high or too low,they will not beneficial to the development of growth-fattening performance and slaughter performance.