急性热应激对肉鸡肉品质及热休克蛋白108mRNA表达的影响

Effect of Acute Heat Stress on Meat Quality and Differential Expression of Heat Shock Protein 108 mRNA in Broilers

研究不同强度热应激对肉鸡感官性状、血液生化指标和热休克蛋白(Hsp)108mRNA表达的影响,将80只30日龄的AA肉鸡随机分为4组,每组20只,对照组环境温度为(25±1)℃,其他3组受试鸡的环境温度迅速上升至(33±1)℃、(37±1)℃、(41±1)℃,并分别持续4h的热应激处理。宰杀后测定鸡胸肉的pH值、滴水损失、肉色和剪切力,利用临床血液病理学和荧光定量PCR的方法,检测宰前不同强度热应激对肉鸡血液生化指标及肌肉、心脏和肝脏中hsp108mRNA表达水平的影响。结果显示,宰前热应激明显降低宰后肉鸡胸肉的pH30min、pH24h和a*值,明显提高宰后肉鸡滴水损失、L*值和剪切力;随热应激温度升高,血清中肌酸激酶(CK)、乳酸脱氢酶(LDH)和丙二醛(MDA)活性逐渐升高,碱性磷酸酶(AKP)活性逐渐降低;hsp108mRNA表达水平大部分呈现下降的趋势,除了心脏33℃组表达量明显增高,其他应激组表达量均有所降低。建立的荧光定量PCR体系特异性好,灵敏度高,符合检测热休克蛋白mRNA转录水平的要求,表明热休克蛋白可作为热应激的一个敏感指标。

The objective of this study was to examine the effect of different intensity of heat stress on sensory properties,blood biochemical parameters and heat shock protein（Hsp） 108 mRNA expression of broilers.Eighty 30-dayage healthy Arbor Acre（AA） broilers were randomly divided into 4 groups,20 broilers for each group.Broilers were heat stressed for 0 h（as a contro1） and for 4 h by rapidly increasing the ambient temperature from（25±1） ℃ to（33±1） ℃,（37±1） ℃ and（41±1） ℃,respectively.The pH,drip loss,color and shear force of broiler breast muscles in every group were investigated.Clinical blood parameter and fluorescence quantitative PCR（FQ-PCR） were used to study the blood biochemical parameters and the expression of heat shock protein108 mRNA in the muscles,hearts and livers of heat-stressed broilers.The results showed that,in comparison with the control group,the pH 30 min,pH 24 h and a＊ value of broiler breast muscles were significantly decreased and the drip loss,L＊ and shear force value were clearly improved.The activities of creatine kinase（CK）,lactate dehydrogenase（LDH） and malondialdehyde（MDA） were significantly increased with the temperature increasing,the activity of alkaline phosphatase（AKP） was decreased.By FQ-PCR,a decreasing tendency was showed in almost heat shock protein 108 mRNA expression,but the expression of the 33 ℃ group in the broiler hearts was significantly increased,other stressed groups were somewhat decreased.The established FQ-PCR method was qualified after the examination and the heat shock protein could be used as a sensitive indicator of heat stress.