营养限制及补偿对羔羊体重及外周血液CD4^+和CD8^+ T淋巴细胞的影响

Effects of Feed Restriction and Compensation on Body Weight,CD4^+ and CD8^+ T-lymphocytes in Peripheral Blood of Lambs

本试验旨在研究羔羊营养限制期(第1~60天)和营养补偿期(第61~150天)体重和外周血液中CD4+和CD8+T淋巴细胞的变化规律。选用80只体况中等、平均体重为(14.72±1.10)kg的3月龄乌珠穆沁羔羊,随机分为对照组(CG)、限制组Ⅰ(RGⅠ)、限制组Ⅱ(RGⅡ)和限制组Ⅲ(RGⅢ)4个组。营养限制期4组饲粮能氮水平分别为代谢能(ME):10.88、10.88、9.41和8.62MJ/kg;粗蛋白质(CP):15%、10%、10%和5.7%。营养补偿期各组饲喂同一能氮水平饲粮(ME:9.75MJ/kg;CP:12%)。在试验期每周称重并在第1天、第30天、第60天、第90天和第150天饲喂前从各组羊颈静脉采血,采用流式细胞仪检测羔羊血液中的CD4+和CD8+T淋巴细胞比例。结果表明:1)营养限制结束,RGⅠ组、RGⅡ组和RGⅢ组平均体重均显著低于CG组(P<0.05)。补偿期RGⅢ组平均日增重显著高于CG组(P<0.05)。2)营养限制前期(第1~30天)各组CD4+和CD8+T淋巴细胞浓度均呈上升趋势。补偿期结束时CD4+T淋巴细胞浓度RGⅠ组最低RGⅡ组最高,CD8+T淋巴浓度RGⅡ组最低RGⅠ组最高,差异均不显著(P>0.05)。结果提示,乌珠穆沁羔羊受不同能氮营养水平限制后体重和免疫机能有补偿效应,而且低能高氮比高能低氮限饲后得到的补偿效果较好,表明限饲蛋白质比限饲能量对补偿生长的负影响更大。蛋白质和能量同时限饲补偿生长最差。

This experiment was conducted to study the effects of feed restriction（1-60 d）and compensation（61-150 d）on body weight,CD4＋ and CD8＋ T-lymphocytes in peripheral blood of lambs.Eighty Wuzhumuqin lambs with average body weight of（14.72±1.10）kg were randomly allotted to control group（CG）,restricted group Ⅰ（RG Ⅰ）,restricted group Ⅱ（RG Ⅱ）and restricted group Ⅲ（RG Ⅲ）,respectively.The diet nutrient levels of the 4 groups were ME：10.88,10.88,9.41 and 8.62 MJ/kg,CP：15%,10%,10% and 5.7%.The four groups were fed the same diet（ME：9.75 MJ/kg,CP：12%）in nutrition compensation period.The lambs were weighed every week in experimental stage and collected blood from jugular vein in each group on the morning of 1,30,60,90,150 day before feeding.CD4＋ to CD8＋ T-lymphocyte ratio was measured by using flow cytometry.The results showed that,1）at the end of nutrition restriction period（1-60 d）,the average body weight（BW）of RG Ⅰ,RG Ⅱ and RG Ⅲ was significantly lower than that of CG（P0.05）,the ADG of RG Ⅲ was significantly higher than that of CG in the compensation growth period（P0.05）.2）During the nutrient restriction period,the concentration of CD4＋ and CD8＋ T-lymphocytes of each group showed increasing tendency.At the end of compensation period,the concentration of CD4＋ in RG Ⅰ was the lowest and that in RG Ⅱ was the highest,the concentration of CD8＋ in RG Ⅱ was the lowest and that in RG Ⅰ was the highest.The results indicated that both the body weight and immunological function of feed restricted lamb had certain compensatory potency.The protein restriction may have more negative effects on compensatory growth.Lamb fed low protein and energy diet showed the least compensatory growth.