关键词：
牦牛;舍饲;集中育肥;生长性能;养分表观消化率;血清生化指标
摘 要：
本试验旨在研究不同蛋白质、能量水平饲粮对舍饲育肥牦牛生长性能、养分表观消化率和血清生化指标的影响.选取年龄相近、体况良好、体重[(180.00±11.67)kg]相近的公牦牛90头,随机分为9组,每组10头.采用2因素3水平随机区组进行设计,即低(12.5%)、中(15.5%)、高(18.5%)3个蛋白质水平和低(6.5 MJ/kg)、中(7.5 MJ/kg)、高(8.5 MJ/kg)3个综合净能水平,按3*3(蛋白质水平*综合净能水平)设计9种不同蛋白质和能量水平的全混合日粮(TMR),每个试验组饲喂1种,预试期20 d,正试期90 d.结果表明:1)饲粮蛋白质水平对所测各生长性能指标影响均不显著(P>0.05);饲粮综合净能水平对总增重(TWG)和平均日增重(ADG)影响显著(P<0.05),对料重比(F/G)影响极显著(P<0.01);饲粮蛋白质水平和综合净能水平两者交互对TWG、ADG和F/G影响极显著(P<0.01).2)饲粮蛋白质水平对粗蛋白质(CP)和粗灰分(Ash)表观消化率影响极显著(P<0.01),对酸性洗涤纤维(ADF)、中性洗涤纤维(NDF)和粗纤维(CF)表观消化率影响显著(P<0.05);饲粮综合净能水平对Ash表观消化率影响显著(P<0.05);饲粮蛋白质水平和综合净能水平两者交互对干物质(DM)和Ash表观消化率影响显著(P<0.05).3)饲粮蛋白质水平对血清尿素氮(UN)含量影响极显著(P<0.01),对磷(P)含量影响显著(P<0.05);饲粮综合净能水平对血清总蛋白(TP)、白蛋白(ALB)、UN、甘油三酯(TG)和总胆固醇(TC)含量影响极显著(P<0.01),对总胆汁酸(TBA)含量影响显著(P<0.05);饲粮蛋白质水平和综合净能水平两者交互对血清碱性磷酸酶(ALP)活性和UN含量影响极显著(P<0.01),对肌酐(CRE)和P含量影响显著(P<0.05).由此得出,在本试验条件下,饲粮综合净能水平对牦牛生长性能的影响大于蛋白质水平的影响;饲粮蛋白质水平对牦牛养分表观消化率的影响大于综合净能水平对其的影响;饲粮中综合净能水平为8.5 MJ/kg、蛋白质水平为15.5%时,舍饲育肥牦牛生长性能最佳.
译 名：
Effects of Different Protein and Energy Levels of Diets on Growth Performance,Nutrient Apparent Digestibility and Serum Biochemical Indexes of Fattening Yaks in Shelter Feeding
单 位：
Animal Husbandry-Pasture and Green Agriculture Institute,Gansu Academy of Agricultural Sciences,Lanzhou 730070,China;College of Animal Science and Technology,Gansu Agricultural University,Lanzhou 730070,China
关键词：
yak%shelter feeding%centralized fattening%growth performance%nutrient apparent digestibility%serum biochemical index
摘 要：
This study aimed to investigate the effects of different protein and energy levels of diets on growth performance,nutrient apparent digestibility and serum biochemical indexes of fattening yaks in shelter feeding.A total of 90 male yaks with good body condition and similar age and body weight(180.00±11.67)kg were randomly divided into 9 groups with 10 yaks per group.Three levels were set for each factor,namely 3 protein levels of low(12.5%),medium(15.5%),and high(18.5%),as well as 3 comprehensive net energy levels of low(6.5 MJ/kg),medium(7.5 MJ/kg),and high(8.5 MJ/kg),9 different total mixed diets(TMR)were designed with 3 protein levels multiplied by 3 energy levels,with each TMR fed to 1 experimental group in the pretest period of 20 days and the formal trial period of 90 days.Results showed as follows:1)protein level had no significant effect on growth performance indexes(P>0.05),while net energy level had significant effects on the total weight gain(TWG)and average daily gain(ADG)(P<0.05),and had an extremely significant effect on ratio of feed to gain(F/G)(P<0.01);the interaction of protein and net energy level had significant effects on TWG,ADG and F/G(P<0.01).2)Protein level had extremely significant effects on the digestibility of crude protein(CP)and Ash(P<0.01),and had significant effects on the digestibility of acid detergent fiber(ADF),neutral detergent fiber(NDF)and crude fiber(CF)(P<0.05);net energy level had a significant effect on the digestibility of Ash(P<0.05);the interaction of 2 factors had significant effects on the digestibility of dry matter(DM)and Ash(P<0.05).3)Protein level had an extremely significant effect on the contents of serum urea nitrogen(UN)(P<0.01),and had significant effects on the content of phosphate(P)in serum(P<0.05);net energy level had extremely significant effects on the contents of total protein(TP),albumin(ALB),triglyceride(TG)and total cholesterol(TC)(P<0.01)and a significant effect on total bile acid(TBA)content in serum(P<0.05);the interaction of 2 factors had extremely significant effects on the alkaline phosphatase(ALP)activity and UN content(P<0.01),and had significant effects on the content of creatinine(CRE)and P(P<0.05).In conclusion,the effects of comprehensive net energy level on growth performance of yaks is greater than that of protein level,while the effect of protein level on nutrient apparent digestibility is greater than that of energy level.Under the conditions of this study,with the dietary comprehensive net energy level of 8.5 MJ/kg and protein level of 15.5%,the growth performance of fattening yaks in shelter feeding is the best.
