本试验旨在研究饲养密度对2～4月龄断奶羔羊生长性能及血清激素、生化和抗氧化指标的影响.选取2月龄、平均体重为(14.86±1.24)kg的健康澳洲白公羔72只,随机分为3组,分别命名为试验Ⅰ组、试验Ⅱ组和试验Ⅲ组,每组3个重复,每个重复8只羊.试验Ⅰ组、试验Ⅱ组和试验Ⅲ组的饲养密度分别为0.875、0.625和0.375 m2/只.试验期60 d.结果表明:1)随着饲养密度的增大,各组羔羊终末体重(FW)、平均日采食量(ADFI)、平均日增重(ADG)和料重比(F/G)均没有显著差异(P＞0.05),但试验Ⅲ组、试验Ⅱ组的F/G较试验Ⅰ组有降低的趋势(P=0.091).2)试验第40天,试验Ⅲ组羔羊血清中甲状腺素(T4)浓度显著高于试验Ⅱ组、试验Ⅰ组(p＜0.05);试验Ⅲ组羔羊血清中三碘甲状腺原氨酸(T3)浓度显著高于试验Ⅰ组(P＜0.05).试验第60天,试验Ⅲ组羔羊血清中T3浓度显著高于试验Ⅱ组、试验Ⅰ组(P＜0.05);试验Ⅲ组、试验Ⅱ组羔羊血清中生长激素(GH)和胰岛素样生长因子-Ⅰ(IGF-Ⅰ)浓度均显著低于试验Ⅰ组(P＜0.05).3)试验第40天,试验Ⅲ组羔羊血清中球蛋白(GLB)、葡萄糖(GLU)、甘油三酯(TG)、总胆固醇(TC)、高密度脂蛋白(HDL)、低密度脂蛋白(LDL)浓度均显著高于试验Ⅱ组、试验Ⅰ组(P＜0.05);试验Ⅲ组羔羊血清中总蛋白(TP)浓度较试验Ⅱ组、试验Ⅰ组有升高的趋势(P=0.086).试验第60天,试验Ⅲ组羔羊血清中GLB浓度显著高于试验Ⅰ组(P＜0.05);试验Ⅲ组羔羊血清中TC、HDL和LDL浓度均显著高于试验Ⅱ组、试验Ⅰ组(P＜0.05).4)试验第40天,各组羔羊血清中抗氧化指标没有显著差异(P＞0.05).试验第60天,试验Ⅲ组羔羊血清中总抗氧化能力(T-AOC)与过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)活性均显著低于试验Ⅱ组、试验Ⅰ组(P＜0.05),血清中丙二醛(MDA)含量显著高于试验Ⅱ组、试验Ⅰ组(P＜0.05).由此可见,试验Ⅲ组羔羊有应激反应发生.从经济效益和动物福利的角度考虑,建议2～4月龄断奶羔羊的饲养密度为0.625 m2/只,羊舍栏位宽度可以设置成2 m.
Effects of Stocking Density on Growth Performance and Serum Hormonal,Biochemical and Antioxidant Indicators of Weaned Lambs
This study aimed to examine the effects of stocking density on the growth performance and serum hormonal,biochemical and antioxidant indicators of weaned lambs aged 2 to 4 months.A total of 72 healthy Australian white male lambs with an average weight of(14.86±1.24)kg were randomly divided into three groups,namely,experimental groups Ⅰ,Ⅱ and Ⅲ,with each group having three replicates and eight sheep in each replicate.The stocking densities in experimental groups Ⅰ,Ⅱ and Ⅲ were 0.875,0.625 and 0.375 m2/lamb,respectively.The experimental period lasted for 60 days.The results showed as follows:1)there were no significant differences in final body weight(FW),average daily feed intake(ADFI),average daily gain(ADG)and feed/gain(F/G)of lamb among the groups(P＞0.05).However,the F/G of lamb in the experimental group Ⅲ and the experimental group Ⅱ showed a decreasing trend compared with the experi-mental group Ⅰ(P=0.091).2)On the 40th day of the experiment,the concentration of thyroxine(T4)in serum of lambs in the experimental group m was significantly higher than that in the experimental group Ⅱ the and experimental group Ⅰ(P＜0.05);additionally,the concentration of triiodothyronine(T3)in serum of lamb in the experimental group Ⅲ was significantly higher than that in the experimental group Ⅰ(P＜0.05).On the 60th day of the experiment,the concentration of T3 in serum of lamb in the experimental group Ⅲ was significantly higher than that in the experimental group Ⅱ and the experimental group Ⅰ(P＜0.05);further-more,the serum growth hormone(GH)and insulin-like growth factor-Ⅰ(IGF-Ⅰ)concentrations of lamb in the experimental group Ⅲ and the experimental group Ⅱ were significantly lower than those in the experimental group Ⅰ(P＜0.05).3)On the 40th day of the experiment,the serum globulin(GLB),glucose(GLU),tri-glyceride(TG),total cholesterol(TC),high density lipoprotein(HDL)and low density lipoprotein(LDL)concentrations of lambs in the experimental group Ⅲ were significantly higher than those in the experiment group Ⅱ and the experimental group Ⅰ(P＜0.05);moreover,there was an increasing trend in the concentra-tion of total protein(TP)in serum of lamb in the experimental group Ⅲ compared with that in the experimen-tal group Ⅱ and the experimental group Ⅰ(P=0.086).On the 60th day of the experiment,the concentration of serum GLB of lamb in the experimental group Ⅲ was significantly higher than that in the experimental groupⅠ(P＜0.05);furthermore,the concentrations of TC,HDL and LDL in serum of lambs in the experimental group Ⅲ were significantly higher than those in the experimental group Ⅱ and the experimental group Ⅰ(P＜0.05).On the 40th day of the experiment,there was no significant change in serum antioxidant indicators of lamb among the groups(P＞0.05).However,on the 60th day of the experiment,the total antioxidant capacity(T-AOC)and the activities of catalase(CAT),glutathione peroxidase(GSH-Px)and superoxide dismutase(SOD)in serum of lamb in the experimental group Ⅲ were significantly lower than those in the experimental group Ⅱ and the experimental group Ⅰ(P＜0.05),while the serum malondialdehyde(MDA)content was significantly higher than that of the experimental group Ⅱ and the experimental group Ⅰ(P＜0.05).Based on the results,the lambs in the experimental group Ⅲ exhibit a stress reaction.Therefore,from the standpoint of animal welfare and economic benefits,it is recommended to provide 0.625 m2 per lamb for stocking density of 2-to 4-month-old weaned lambs,and the width of the sheep pens should be set to 2 meters.[Chinese Journal of Animal Nutrition,2024,36(7):4544-4553]
万方数据
维普
