Effect Of Acute Heat Stress On The Expression Patterns Of Pancreatic Digestive Enzyme In Muscovy Ducks

China is one of powerful poultry raising couniries.In most areas of China, especially in the south, high temperature almost lasts the whole summer, which leads a serious heat stress to poultry. Heat stress induces production performances, further causes great economic loss, affecting the duck production in China.Muscovy duck is a good kind of lean ducks,which plays an important role in the south water fowl production,whose most suitable production temperature was15-25℃. In summer, when the temperature was above32℃, the breath frequency and metabolic heat production might increase, and the muscovy ducks were under heat stress. Heat stress also affected the digestion, metabolism, blood circulation, blood biochemical indicator, endocrine, immunization and so on.Yuyao Muscovy Ducks (n=16) were housed in large coops (4birds Per coop) and the coops were placed in a controlled-climate chamber. The room temperature was suddenly inereased from22±1℃to38±1℃within20min and the broilers were heat stressed for oh(control),2h,3h and5h respectively. On terminating the heat treatment, ducks were manually eviscerated,and the pancreas were quickly dissected and were frozen in liquid nitrogen, and then stored at-70℃. Real-time fluorescence quantitative PCR was developed to estimate effects of temperature on expression of pancreatic trypsin I, trypsin Ⅱ, amylase and lipase mRNA in Muscovy Ducks.The results showed that acute heat stress reduced pancreatic amylase, pancreatic lipase.trypsin I and trypsin II gene expression.The expression of pancreatic amylase genes were reduced significantly after2h(P<0.05),3h(P<0.05),5h(P<0.01) heat exposure.After2h heat exposure, pancreatic lipase gene expression level significantly reduced (P<0.01); after3h, pancreatic lipase gene expression reduced, but the difference was not significant (P>0.05); after5h, the level of pancreatic amylase gene significantly reduced compared with the control (P<0.05).After2h,3h and5h exposure, trypsin I gene expression level were significantly reduced compared with the control (P<0.05). After2h heat exposure,trypsin Ⅱ gene expression reduced, but the difference was not significant (P>0.05); after3h,5h, trypsin Ⅱ gene expression significantly reduced(P<0.05).