抗应激添加剂对运输后肉牛应激蛋白mRNA和蛋白表达水平的影响

Effects of Anti-Stress Additives on mRNA and Protein Expression Levels of Stress Protein in Beef Cattle after Transportation

为探讨抗应激添加剂对肉牛因运输应激导致机体应激蛋白表达波动的影响,揭示抗应激添加剂的作用以及肉牛运输应激发生的分子机理奠定理论基础,本试验选择27头体重和体况相近的健康出栏育肥辽育白牛,随机分成3组(n=9),其中对照组饲喂常规基础饲粮,2个添加剂组饲粮中分别添加抗应激1号和2号,饲喂10d后,在20℃、相对湿度51%的环境条件下,以50~60km·h-1的速度在公路上运输5h,分别采集运输前及运输后的肉牛血液及运输后的肉牛肌肉组织,制备血清,提取组织RNA及蛋白,采用ELISA、qRT-PCR、Western Blotting等方法分别检测血清中HSP70含量和肌肉组织中应激蛋白HSP27、HSP70及HSP90的mRNA和蛋白水平的表达量。结果表明:运输后各组肉牛血清HSP70含量显著高于运输前(p<0.05);添加剂组同对照组相比,运输前后血清HSP70均明显下降(p<0.05或p<0.01)。抗应激1号组肌肉组织HSP27、HSP70和HSP90的mRNA相对表达量较对照组明显下降(p<0.05),抗应激2号组肌肉组织中HSP90mRNA的表达量较抗应激1号组显著升高(p<0.05)。两个抗应激添加剂组肌肉组织HSP70和HSP90的蛋白表达量较对照组明显减少(p<0.05)。运输使肉牛血清和肌肉组织中应激蛋白含量增加,而抗应激添加剂可影响运输后肉牛血清及肌肉组织中应激蛋白的水平,尤以抗应激1号作用更明显。

The aim of this study was to investigate the effects of anti-stress additives on the fluctuation of stress protein expression in beef cattle caused by transport stress, and to provide a theoretical foundationfor theaction of anti-stress additive and the molecular mechanism of transport stress. Twenty-seven healthy Liao white cattle with similar body weight and body condition were selected. They were randomly divided into three groups(n=9). The control group was fed with routine basic diet,and the two additive groups were fed with anti-stress No. 1 and No. 2, respectively. After 10 days of feeding, they were transported on the highway for 5 h at a speed of 50-60 km·h-1, in 20 ℃ and 51% relative humidity ambient. The blood and muscle tissues of beef cattle were collected before and after transportation, respectively. The serum and extracted tissue RNA and protein were prepared respectively. The contents of HSP70 in serum and the expression of HSP27, HSP70 and HSP90 in muscle tissue were detected by ELISA, qRT-PCR and Western Blotting, respectively.The serum HSP70 content of beef cattle in each group after transportation was significantly higher than that before transportation(p<0.05). Compared with the control group,the serum HSP70 in the additive groups decreased significantly before and after transportation(p<0.05 or p<0.01). The m RNA relative expression of HSP27, HSP70 and HSP90 in muscle tissue of anti-stress group 1 was significantly lower than that of control group(p<0.05). The mRNA expression of HSP90 in muscle tissue of anti-stress group 2 was significantly higher than that of anti-stress group 1(p<0.05). The protein expression of HSP70 and HSP90 in muscle tissue of the two anti-stress additives groups were significantly lower than that of the control group(p<0.05).Transportation increased the levels of stress proteins in serum and muscle tissues of beef cattle. Anti-stress additives can affect the levels of stress proteins in serum and muscle tissues of beef cattle after transportation, especially anti-stress No. 1.