饲粮2-羟基-4-(甲硫基)丁酸异丙酯添加水平对山羊生长性能、营养物质表观消化率及血清生化指标和激素水平的影响

Effects of 2-Hydroxy-4-(Methylthio) Butanoic Acid Isopropyl Ester Supplemental Level on Growth Performance,Nutrient Apparent Digestibility,Serum Biochemical Indices and Hormone Levels of Goats

本试验旨在研究饲粮2-羟基-4-(甲硫基)丁酸异丙酯(HMBi)添加水平对山羊生长性能、营养物质表观消化率及血清生化指标和激素水平的影响,以确定山羊饲粮中HMBi的最佳添加水平。选择36只2.5月龄左右、平均体重为(13.33±1.71)kg的山羊,随机分为4组,每组3个重复,每个重复3只(公阉羊1只,母羊2只),各组山羊分别饲喂HMBi添加水平为0(对照组)、0.05%、0.10%、0.20%(干物质基础)的试验饲粮。预试期10 d,正试期40 d。结果显示:1)0.10%组山羊的平均日增重最高,为158.89 g/d,料重比最低,为4.82,经济效益最佳,且其平均日增重和毛收益均显著高于对照组(P<0.05),0.20%组、0.50%组和对照组的平均日增重分别为141.11、140.56、119.44 g/d。2)干物质、中性洗涤纤维、酸性洗涤纤维和消化能表观消化率各组间均无显著差异(P>0.05)。0.10%组的粗蛋白质表观消化率显著高于对照组(P<0.05)。3)试验第1天,各组山羊血清尿素氮(UN)、葡萄糖(GLU)、甘油三酯(TG)、总胆固醇(TC)、游离脂肪酸(NEFA)、总氨基酸(TAA)含量及生长激素(GH)与类胰岛素生长因子-Ⅰ(IGF-Ⅰ)水平均无显著差异(P>0.05)。试验第31天,0.20%组山羊血清TG含量显著高于其他3组(P<0.05);0.20%组山羊血清TC含量显著低于对照组(P<0.05);0.20%组山羊血清NEFA含量极显著高于对照组(P<0.01),显著高于0.05%组(P<0.05);0.05%、0.10%和0.20%组山羊血清TAA含量显著高于对照组(P<0.05);0.05%和0.10%组血清GH水平显著高于对照组(P<0.05),0.20%组血清GH水平与对照组相比有增加的趋势(P=0.084);血清IGF-Ⅰ水平各组之间无显著差异(P>0.05)。由此说明,饲粮中添加HMBi有利于提高山羊对蛋白质的消化利用,促进山羊生长,且添加水平为0.10%(干物质基础)时经济效益最佳。

This experiment was conducted to investigate the effects of 2-hydroxy-4-（methylthio） butanoic acid isopropyl ester （HMBi） supplementaal level on growth performance, nutrient apparent digestibility, serum biochemical indices and hormone levels of goats, aiming to determine the optimal supplemental level of HMBi in diets for goats. Thirty-six goats of about 2.5-month-old with an average body weight of （13.33±1.71） kg were randomly assigned to 4 groups with 3 replicates within each group, and one male goat and two female goats within each replicate. The goats in the 4 groups were fed the experimental diets containing 0 （control group）, 0.05%, 0.10% and 0.20% HMBi on dry matter basis, respectively. The pre-experiment lasted for 10 days, and the formal experiment lasted for 40 days. The results showed as follows： 1） the average daily gain of the control group, 0.05% group, 0.10% group and 0.20% group was 119.44, 140.56, 158.89 and 141.11 g/d , respectively. The 0.10% group had the greatest average daily gain, the lowest feed/gain of 4.82, and the best economic benefit. The average daily gain and gross returns of the 0.10% group were significantly greater than those of the control group （ P 〈0.05）. 2） No significant differences were found in apparent digestibility of dry matter, neutral detergent fiber, acid detergent fiber and digestible energy among groups （ P 〉 0.05 ）. The apparent digestibility of crude protein of the 0.10% group was significantly higher than that of the control group （ P 〈 0.05）. 3） There were no significant differences among all groups on the 1st day of the test in terms of the contents of urea nitrogen, glucose, triglycerides, total cholesterin, non-esterified fatty acid, total amino acid, and the levels of growth hormone and insulin-like growth factor-1 in serum （ P 〉0.05）. On the 31st day of the test, the serum triglycerides content of the 0.20% group was significantly higher than that of the other three groups （ P 〈0.05） ; the serum total cholesterin content of the 0.20% group was significantly lower than that of the control group （ P 〈0.05）; the serum non-esterified fatty acid content of the 0.20% group was significantly higher than that of the control group （ P 〈0.01） and the 0.05% group （ P 〈0.05）; the serum total amino acid content of the control group was significantly lower than that of the other groups （ P 〈0.05）; the serum growth hormone level of the control group was significantly lower than that of the 0.05% and 0.10% groups （ P 〈 0.05 ）; the 0.20% group tended to increase serum growth hormone level compared with the control group （ P =0.084）; there was no significant difference in serum insulin-like growth factor-Ⅰ level among all groups （ P 〉0.05）. It is concluded that dietary supplementation of HMBi can improve the digestive utilization of protein, and then promote the growth of goats. Moreover, supplementation of 0.10% HMBi on the dry matter basis shows the best economic benefits.