不同粗蛋白质水平饲粮对烟台黑猪生长肥育性能及胴体肉品质的影响

选择2013年春季出生、生长发育良好、胎次相近、体重35k左右的烟台黑猪仔猪80头为研究对象，随机分为3组，试验1组26头饲喂高蛋白质水平饲粮，试验2组26头饲喂中等蛋白质水平饲粮，试验3组28头饲喂低蛋白质水平饲粮。每组3个重复，每个重复8—10头猪。结果表明，肥育期和全期日增重都以高蛋白质水平组最高，分别比中等蛋白质水平组和低蛋白质水平组提高14.36％（P〈0．05）、4．18％（P〉0．05）和9．87％（P〈0．05）、4．42％（P〉0．05）；全期料重比以高蛋白质水平组最低，分别比中等蛋白质水平组和低蛋白质水平组降低9．30％和0．92％。屠宰率和平均背膘厚都以高蛋白质水平组最高，分别比中等蛋白质水平组和低蛋白质水平组提高1．04％（P〉0．05）、2．04％（P〉0．05）和4．53％（P〉0．05）、5．70％（P〉0．05）；瘦肉率以低蛋白质水平组最高，分别比高蛋白质水平组和中等蛋白质水平组提高0．55％（P〉0．05）和3．75％（P〉0．05）。滴水损失以中等蛋白质水平组最低，分别比高蛋白质水平组和低蛋白质水平组降低45．61％（P〉0．05）和26．97％（P〉0．05）；剪切力和肌纤维直径都以中等蛋白质水平组最低，分别比高蛋白质水平组和低蛋白质水平组降低14．59％（P〉0．05）、14．50％（P〉0．05）和10-38％（P〉0．05）、0．57％（P〉0．05）；肌内脂肪以中等蛋白质水平组最高，分别比高蛋白质水平组和低蛋白质水平组提高17．95％（P〉0．05）、32．37％（P〉．05）。背最长肌17种氨基酸含量各组间差异不显著；鲜味氨基酸占总氨基酸比例和必需氨基酸占总氨基酸比例以低蛋白质水平组最高，分别比高蛋白质水平组和中等蛋白质水平组提高0．48％、2．09％和0．31％、3．84％，组间差异不显著。棕榈酸以中等蛋白质水平组最高，分别比高蛋白质水平组和低蛋白质水平组提高6．08％（P〉0．05）、7．15％（P〈0．05）；硬脂酸和亚油酸以高蛋白质水平组最高，分别比中等蛋白质水平组和低蛋白质水平组提高1．78％（P〉0．05）、7．74％（P〉0．05）和32．97％（P〉0．05）、11．67％（P〉0．05）；油酸以低蛋白质水平组最高，分别比高蛋白质水平组和中等蛋白质水平组提高4．82％（P〉0．05）和1．44％（P〉0．05）。

Effects of Different Dietary Crude Protein Levels on Growth Performance,Carcass Performance and Pork Quality of Yantai Black Pigs

In the study,80 healthy piglets of weight 35 kg,born in the spring of 2013,were selected,randomly divided into three groups.Group 1（n=26）,Group 2（n=26） and Group 3（n=28） were feed diets with high,middle and low crude protein levels,respectively.The results indicated that diets with different crude protein levels significantly affected the average daily gain（ADG） of fattening period（60~100 kg） as well as the whole experimental period（35~100 kg）. Specifically,the ADG was highest in pigs fed diet with high crude protein levels had,and compared with middle and low levels,their average daily gain were improved 14.36%（P0.05）,9.87%（P0.05） respectively.Feed/gain ratio was highest for the high crude protein level,and compared with middle and low levels,it decreased 9.30% and 0.92%,respectively.Diets with different crude protein levels did not significantly influence the carcass performance.Specifically,slaughter rate and average backfat thickness were highest in pigs fed diet with high crude protein level,and compared with middle and low levels,they were improved 1.04%（P〉0.05） and 2.04%（P〉0.05）,4.53%（P〉0.05） and 5.70%（P〉0.05） respectively.However,the lean rate was highest in pigs fed diets with low crude protein level,and compared with middle and low levels,it was improved 0.55%（P〉0.05） and 3.75%（P〉0.05） respectively.Diets with different crude protein levels did not significantly affect the meat quality either. Specifically,drip loss,shear strength,muscle fiber diameter and intramuscular fat（IMF） had best score in pigs fed diet with middle crude protein level,and compared with high and low levels,drip loss decrease 45.61%（P〉0.05） and 26.97%（P〉0.05）;shear strength decreased 14.59%（P〉0.05） and 14.50%（P〉0.05）,muscle fiber diameter decreased 10.38%（P〉0.05） and 0.57%（P〉0.05）,IMF improved 17.95%（P〉0.05） and 32.37%（P〉0.05）.Diets with different crude protein levels did not significantly affect the content of each amino acid.Specifically,flavor amino acids/total amino acid ratio and essential amino acid/total amino acid ratio were highest in pigs fed diet with low crude protein level, and compared with high and middle levels,they were improved 0.48%（P〉0.05） and 2.09%（P〉0.05）,0.31%（P〉0.05） and 3.84%（P〉0.05）,respectively.As for the four fatty acids,diets with different crude protein levels significantly affected the content of palmitic acid,while insignificantly affected the content of the other three fatty acids.Stearic acid and linoleic acid were highest in pigs fed diet with high crude protein level,and compared with middle and low levels,they were improved 1.78%（P〉0.05） and 7.74%（P〉0.05）,32.97%（P〉0.05） and 11.67%（P〉0.05） respectively. Oleic acid were highest in pigs fed diet with low crude protein level,and compared with high and middle levels,they were improved 4.82%（P〉0.05） and 1.44%（P〉0.05） respectively.