Habibian Mahmood, Ghazi Shahab, Moeini Mohammad Mehdi, Abdolmohammadi Alireza
Department of Animal Science, Faculty of Agriculture, Razi University, Kermanshah, Iran,
Int J Biometeorol. 2014 Jul;58(5):741-52. doi: 10.1007/s00484-013-0654-y. Epub 2013 Mar 23.
A study was conducted using 360 broiler chickens to evaluate the effects of dietary vitamin E (0, 125 and 250 mg/kg), selenium (Se, 0, 0.5 and 1 mg/kg), or their different combinations on immune response and blood biological parameters of broilers raised under either thermoneutral (TN, 23.9 °C constant) or heat stress (HS, 23.9 to 37 °C cycling) conditions. Humoral immunity was assessed by intravenous injection of 7% sheep red blood cell (SRBC) followed by evaluation of serum for antibody titers in primary and secondary responses. Heterophil to lymphocyte (H/L) ratio also determined as an indicator of stress. Furthermore, at the end of the experiment, birds were bled for determination of some biological parameters. There was a significant reduction in body weight and feed intake, but the feed conversion ratio increased when the birds were exposed to HS (P<0.05). Body weight and feed intake were not influenced significantly by dietary vitamin E and Se (P>0.05), whereas feed conversion was improved significantly by 125 mg/kg vitamin E (P<0.05). The liver and lymphoid organ weights as well as IgM and IgG, antibody titers for primary and secondary antibody responses to SRBC were reduced significantly under HS (P<0.05). Heat stress also resulted in a significant increase in H/L ratio (P<0.05). Dietary vitamin E resulted in improvement of primary and secondary antibody responses both in TN and HS broilers (P<0.05). The HS birds also showed an improved antibody titer in secondary response with high concentration of Se (P<0.05). Vitamin E and Se had interactive effects on anti-SRBC titers; however, no consistent differences were found between dietary levels during the study. The H/L ratio decreased by feeding vitamin E at both levels either under HS or TN conditions (P < 0.05). The serum concentrations of glucose, triglycerides, total cholesterol, and LDL-cholesterol were increased but serum HDL-cholesterol decreased in HS broilers (P<0.05).
采用360只肉鸡进行了一项研究，以评估日粮中维生素E（0、125和250毫克/千克）、硒（Se，0、0.5和1毫克/千克）或它们的不同组合对在热中性（TN，23.9℃恒温）或热应激（HS，23.9至37℃循环）条件下饲养的肉鸡免疫反应和血液生物学参数的影响。通过静脉注射7%绵羊红细胞（SRBC）评估体液免疫，随后评估血清中初次和二次反应的抗体滴度。还测定了异嗜性粒细胞与淋巴细胞（H/L）比值作为应激指标。此外，在实验结束时，采集鸡的血液以测定一些生物学参数。当鸡暴露于热应激时，体重和采食量显著降低，但饲料转化率升高（P<0.05）。日粮中的维生素E和硒对体重和采食量没有显著影响（P>0.05），而125毫克/千克的维生素E显著改善了饲料转化率（P<0.05）。在热应激条件下，肝脏和淋巴器官重量以及对SRBC的初次和二次抗体反应的IgM和IgG抗体滴度显著降低（P<0.05）。热应激还导致H/L比值显著升高（P<0.05）。日粮中的维生素E改善了热中性和热应激肉鸡的初次和二次抗体反应（P<0.05）。热应激鸡在高浓度硒的二次反应中也表现出抗体滴度升高（P<0.05）。维生素E和硒对抗SRBC滴度有交互作用；然而，在研究期间不同日粮水平之间未发现一致的差异。在热应激或热中性条件下，两种水平的维生素E喂养均使H/L比值降低（P<0.05）。热应激肉鸡的血清葡萄糖、甘油三酯、总胆固醇和低密度脂蛋白胆固醇浓度升高，但血清高密度脂蛋白胆固醇降低（P<0.05）。
