Effects Of Thermal Environmental Factors And Ammonia On The Broiler Health

Environment factors play important role in poultry.Growth performance,meat quality and survival rate of boilers decrease in adverse environment.In broiler house,temperature and relative humidity are two important factors to form the thermal environment,and ammonia is the main pollutant.The control of harmful gases and temperature have been the key points in poultry farming,while the regulation of relative humidity is ignored.Therefore,this subject applied iTRAQ technology to analyze the proteome changes in broiler tracheal proteome under high concentration of ammonia,as well as the differential proteome of hypothalamus in response to high temperature,in order to obtain potential mechanisms of ammonia toxicity and regulation in boiler under heat exposure.Meanwhile,the preliminary study of the effect of relative humidity on broiler immune function was put forward,which could provide reference for rational control of poultry breeding environment.In ammonia concentration of 75±3 ml/m3 for 21 days(21 d,42 d),the broiler trachea showed absence of cilia,epithelial hyperplasia,and inflammatory infiltration,as well as the increased level of oxidative stress and pro-inflammatory cytokines.There were 119 differential proteins,which enriched in the immune response and muscle contraction,and over-expression of mucin,which is a common feature of airway disease,was also observed.These results indicated the high concentration of ammonia may induce disturbance of immune responses and muscle contraction,which contributed to low resistibility and defective respiratory function.When broiler exposed in high temperature of 32 ±1? for 8 h(21 d),the level of MDA,IL-1?,IL-6 and corticosterone were increased,and 51 proteins were differentially expressed in hypothalamus.Majority of these proteins distributed in cellular process and metabolic process.Several proteins involved in neurotransmitter release and vesicle-mediated transport.These results suggests that proteins of hypothalamus were considered to alleviate inflammation and provide a negative feedback for hormone release in response to high temperature,and cellular homeostasis in hypothalamus may be disturbed under heat stress.In addition,broiler with low daily age housed in abnormal relative humidity(30%or 90%,1 d-42 d)showed decreased index of thymus and bursa,percentage of lymphocytes and ratio of CD4+/CD8+,and increased pro-inflammatory cytokines.As the chicken grew,the level of MDA and SOD activity significantly increased,and anti-inflammatory cytokines increased while pro-inflammatory cytokine decreased for broilers under low relative humidity.These results suggest that abnormal relative humidity may induce inflammation,affect the development of immune organ,and change the percentage and subsets of lymphocytes,which reduce the immune function.Meanwhile,under the chronic stress induced by low relative humidity,the antioxidant capacity may increase in order to reduce oxidative stress,and the immunity may recover by regulating cytokines secretion.Above all,these finding are helpful for further hazard assessment for ammonia,high temperature and relative humidity in raising environment,and may serve as a valuable reference to prevent the negative impacts.