慢性寒冷应激对绵羊体增重、血清免疫和抗氧化机能的影响

本试验旨在探究慢性寒冷应激对绵羊体增重、血清免疫和抗氧化机能的影响.选取体重为(55.50±0.80)kg、毛丛长度为(11.60±1.47)cm的3岁杜蒙杂交母羊18只,随机分为3组:舍内加热组(对照组)、舍内组和舍外组,每组6只.试验共28 d,每天记录各组试验羊的采食量,并于试验第1、14和28天称重,计算平均日...

Effects of Chronic Cold Stress on Body Weight Gain,Serum Immune and Antioxidative Functions of Sheep

This study was conducted to evaluate the effects of chronic cold stress on body weight gain,serum immune and antioxidative function of sheep.Eighteen 3-year-old Dorper×Mongolian crossbred ewes,with similar body weight of(55.50±0.80)kg and unstretched staple length of(11.60±1.47)cm,were randomly allocated into three groups:indoor heating group furnished with a radiator(control group),indoor group and outdoor group and each group had 6 sheep.The trial lasted for 28 days.Each sheep was recorded feed intake every day and body weight on days 1,14 and 28.The average daily weight gain(ADG)and average daily feed intake(ADFI)were calculated.Blood and leukocyte samples were collected on days 14 and 28 to analysis the immune and antioxidant indexes and the related gene relative expression.The results showed that,compared with control group,1)the ADG in outdoor group was significantly decreased(P<0.05);2)on day 14,the content of interleukin(IL)-1 in serum and the relative expression levels of IL-1βand IL-2 genes in leukocyte in outdoor group were significantly decreased(P<0.05).The content of IL-1 in serum and the relative expression level of IL-1βgene in leukocyte in indoor group were significantly decreased(P<0.05).On day 28,the contents of immunoglobulin(Ig)G and IL-2 in serum in outdoor group were significantly decreased(P<0.05),while the content of tumor necrosis factor-α(TNF-α)in serum and the relative expression level of its gene were significantly increased(P<0.05).The content of IL-2 in serum in indoor group was significantly decreased(P<0.05);3)on day 14,the activities of glutathione peroxidase(GPx)and total superoxide dismutase(T-SOD)in serum and the relative expression levels of GPx and superoxide dismutase 1(SOD1)genes in leukocyte in outdoor group were significantly decreased(P<0.05),while the content of malonaldehyde(MDA)in serum was significantly increased(P<0.05).On day 28,the activities of CAT,GPx and T-SOD,total antioxidant capacity(T-AOC)and the relative expression levels of GPx and SOD2 genes in leukocyte in outdoor group were significantly decreased(P<0.05),while the relative expression levels of CAT and Nrf 2 genes in leukocyte and the content of MDA in serum were significantly increased(P<0.05).The activity of CAT and T-AOC in serum and the relative expression levels of their genes in leukocyte in indoor group were significantly decreased(P<0.05).In conclusion,chronic cold stress can decrease body weight gain and suppress serum immunity and antioxidant level of sheep.However,the heat-preservation sheep house which furnished with a radiator can significantly relieve these negative effects.