不同日粮蛋白水平对乌金猪生长性能和胴体品质的影响

Effect of Dietary Protein Levels on Growth Performance and Carcass Composition in Wujin Pig

旨在研究日粮不同蛋白水平对乌金猪生长性能及胴体品质的影响及最佳生长性能和胴体品质所需的日粮适宜蛋白水平。选取体重15妇左右的乌金猪90头，随机分为5组，每组18头。试验采用单因子随机分组设计，在15～30、30～60和60～100kg阶段的日粮蛋白水平分别为最高蛋白水平（HHP，18％、16％和14％）、中高蛋白水平（HMP，17％、15％和13％）、中蛋白水平（MMP，16％、14％和12％）、中低蛋白水平（MLP，15％、13％和11％）和最低蛋白水平（LLP，14％、12％和10％）。试验期至体重达100kg，统计日增重及料重比；分别在30、60和100kg体重时屠宰，测定胴体组成指标，采用模糊综合评定系统分析并确定最佳生长性能和胴体品质日粮适宜蛋白水平。结果表明，随日粮蛋白水平的降低，各生长阶段的日增重逐渐降低，料重比逐渐升高，15～30k阶段（除HHP与LLP外）日增重无显著差异（P〉0．05），30～60和60～100kg阶段日增重差异显著（P〈0．01或P〈0．05），由高到低5个蛋白水平达100kg体重的时间分别为163、168、173、179和185d。胴体品质在30kg体重时，除板油重和眼肌面积外其他性状无明显差异（P〉O．05）。在60和100kg体重时随日粮蛋白水平的降低，瘦肉重、瘦肉率和眼肌面积降低，脂肪重、脂肪率和背膘厚增加，高、中、低蛋白组间差异显著（P〈0．05或P〈0．01）。以无脂瘦肉重为指标，通过拟合曲线确定15～30、30～60和60～100kg阶段最佳生长性能所需的日粮适宜蛋白水平分别为15．95％、14．30％和11．81％。以瘦肉率、背膘厚、眼肌面积为评定胴体品质的代表指标，通过综合评定确定30、60和100kg体重时最优胴体品质适宜的日粮蛋白水平分别为16．47％、13．71％和10．72％。综合评定无脂瘦肉重和胴体品质，15～30、30～60和60～100kg阶段乌金猪获得最佳无脂瘦肉重和胴体品质的日粮适宜蛋白水平分别为14．98％、11．34％和11．71％。研究结果为乌金猪的合理饲养提供科学依据。

The aim of this study was to investigate the effect of dietary protein levels on growth performance and carcass composition so as to investigate the suitable dietary protein level according to the best lean meat growth and carcass composition by Fuzzy Comprehensive Judgment Model. Ninety pigs were randomly allotted into five groups fed diet containing different protein levels. There are eighteen pigs in each group with three replicates. Six pigs were used in per replicates. The experiment was designed by single factor random arrangement. The dietary protein levels were high high protein（HHP, 18%, 16% and 14%）, high medium protein（HMP, 17%, 15% and 13%）,medium medium protein（MMP, 16%, 14% and 12%）, medium low protein （MLP, 15%, 13% and ll%）and low low protein（LLP, 14%, 12% and 10%）respectively during 15-30, 30-60 and 60-100 kg body weight. The daily gain and feed efficiency were calculated. The carcass composition was measured when the pigs were slaughtered at 30, 60 and 100 kg body weight. Fuzzy Comprehensive Judgment Model was analyzed to make sure the suitable dietary protein level to attain the best growth performance and carcass composition in Wujin pigs during different growth stages. The results showed that dietary protein levels affected significantly the growth performance and carcass composition during different growth stages. With dietary protein level decreased, the daily gain reduced but the ratio of feed to weight increased gradually. The difference was significant among high group, medium group and low groups during 30-60 and 60- 100 kg body weight. The time reaching 100 kg body weight of five groups were the days of 163, 168, 173, 179 and 185, respectively. The carcass composition except for suet weight and loin eye area were no significant difference among each groups at 30 kg body weight. Lean meat weight, lean meat percentage and loin eye area decreased, but fat meat weight, fat meat percentage and backfat thickness increased with dietary protein levels reducing at 60 and 100 kg body weight. Moreover, the differences were significant among high, medium and low groups. Fuzzy Comprehensive Judgment Model was analyzed basing on the lean meat weight. The suitable dietary protein levels were 15.95%, 14.30% and 11.81% during 15-30, 30-60 and 60-100 kg body weight respectively from the fitting curve. Fuzzy Comprehensive Judgment Model was draw depending on the lean meat percentage, backfat thickness and loin eye area which represented the carcass composition. The suitable dietary protein levels were 16.47%, 13.71%and 10. 72% during 15- 30, 30-60 and 60-100 kg body weight, respectively. It was revealed that the suitable dietary pro- tein levels were 14.98%, 11.34% and 11.71% combined lean meat growth with carcass charac teristics by Fuzzy Comprehensive Judgment Model. This result could provide scientific basis for the reasonable feeding of Wujin pigs.