开食料中赖氨酸、蛋氨酸、苏氨酸和色氨酸对断奶羔羊生长性能、氮利用率和血清指标的影响

Effects of Lysine,Methionine,Threonine and Tryptophan in Starter on Growth Performance,Nitrogen Utilization and Serum Parameters in Weaned Lambs

本试验旨在利用氨基酸部分扣除法研究开食料中赖氨酸、蛋氨酸、苏氨酸和色氨酸对断奶后羔羊生长性能、氮利用率和血清学指标的影响,以期确立氨基酸限制性顺序和比例。选取100只50日龄、平均体重为11.00kg的健康湖羊断奶公羔羊,随机分成5组,每组4个重复,每个重复5只羊。采用单因素试验设计,对照组(PC)饲喂氨基酸平衡的开食料,其赖氨酸、蛋氨酸、苏氨酸和色氨酸含量分别为1.16%、0.38%、0.58%和0.16%,4个试验组依次在PC组的基础上分别扣除30%赖氨酸、蛋氨酸、苏氨酸和色氨酸(PD-Lys、PD-Met、PD-Thr和PD-Trp组)。预试期为10d,正试期为60d。分别于羔羊80~90和110~120日龄进行两期氮平衡试验。结果表明:1)PCMet组羔羊120日龄体重、日增重和饲料转化率显著低于PC、PD-Thr和PD-Trp组(P<0.05)。2)80~90日龄PD-Lys和PD-Met组尿N排放量显著高于PC组(P<0.05),PD-Met组N沉积量、N沉积率和N表观生物学价值显著低于PC组(P<0.05),110~120日龄PD-Met组N沉积量、N沉积率、N表观消化率和N表观生物学价值显著低于PC组(P<0.05)。3)以最大NR为衡量指标时,80~90和110~120日龄两阶段的限制性氨基酸顺序为:Met>Lys>Thr>Trp和Met>Lys>Trp>Thr。获得最大NR时Lys、Met、Thr和Trp 4种氨基酸模型分别为100∶37∶45∶12和100∶41∶39∶12。4)90日龄PD-Met组葡萄糖显著高于PC组(P<0.05),120日龄PD-Met组总蛋白、球蛋白和胆固醇显著低于PC组(P<0.05)。综上所述,60~120日龄断奶羔羊开食料中赖氨酸、蛋氨酸、苏氨酸和色氨酸的适宜比例为100∶(37~41)∶(39~45)∶12,限制性氨基酸顺序分别为Met>Lys>Thr>Trp(80~90d)和Met>Lys>Trp>Thr(110~120d)。

This experiment aimed to investigate on growth performance, nitrogen utilization an limiting sequence and proportion of amino a healthy male Hu lambs at 50 days old with an the effects of Lys, Met, Thr and Trp in starters d serum indices of weaned lambs, and to determine cids by partial deduction method. One hundred average weight of 11.00 kg were randomly dividedinto 5 groups and each group had 4 replicates with 5 lambs per replicate according to single factor design. The control group was fed starter with balanced amino acid （PC） with Lys （1. 16%）, Met （0.38%）, Thr （0.58%） and Trp （0.16%）, respectively. The 4 experimental groups were fed the starter deducting Lys, Met, Thr and Trp at 30%, respectively compared with control group （PD-Lys, PD-Met, PD-Thr and PD-Trp group）. The experiment lasted for 70 days; Dur- ing 80-90 and 110-120 days old, nitrogen balance of lambs was determined. The results showed as follows：1） The BW, ADG and F/G in PD-Met group were significantly lower than that in PC, PD-Thr and PD-Trp groups （P〈0.05） on 120 days old. 2） Urinary nitrogen emission in PD-Lys and PD-Met groups was significantly higher than that in PC （P〈0.05） during 80-90 days old. Nitrogen deposition, nitrogen retention ratio and nitrogen apparent biological value in PD-Met group were significantly lower than that in PC group （P〈0.05） during 80-90 days old, and nitro- gen deposition, nitrogen retention ratio, nitrogen apparent digestibility and nitrogen apparent bi- ological value in PD-Met group were significantly lower than that in PC group（P〈0.05） during 110-120 days old. 3） The limiting sequence of 4 amino acids were Met〉Lys〉Thr〉Trp and Met〉Lys〉Trp〉Thr from 80 to 90 days old and from 110 to 120 days old, respectively, the proper ratio of Lys, Met, Thr and Trp was 100 ： 87 ： 45 ： 12 and 100 ： 41 ： 39 ： 12 when obtaining the maximum NR. 4） Glucose concentration in PD-Met group was significantly higher than that in PC （P〈0.05） on 90 days old. Serum total protein, globulin and cholesterol in PD- Met group was significantly lower than that in PC （P〈0.05） on 120 days old. In conclusion, the proper ratios of Lys, Met, Thr and Trp in starter of weaned lambs during 60-120 days old was 100 ： （37-41） ：（39-45） ： 12. The limiting sequence were Met〉Lys〉Thr〉Trp（80-90 days old） and Met〉Lys〉Trp〉Thr（110-120 days old）, respectively.