Study on the pathogenic damage of environmental particles in henhouses at different laying periods to mice
Particulate matter in livestock houses can cause damage to the respiratory system of livestock and poultry and farm workers.The aim of this study was to explore the pathogenic damage of environmental particulate matter in laying hens during different laying periods to mice.The environmental particulate matter samples were collected from the henhouse during the pre-laying period of hens(17-30 weeks of age),the peak laying period(31-50 weeks)and the late laying period(>50 weeks),respectively.Then,the suspension of the samples was prepared to infect BALB/c mice by nasal drip.The mice were randomly divided into the control group,the pre-laying group,the peak laying group and the late laying group.The changes in the body weight,lung index,pathological HE staining sections of lung tissue and the expression levels of various cytokines in the mice after inhalation of the environmental particles in henhouses at different laying periods were analyzed to observe the damage to their lung tissue.The results were as follows:With the passage of the laying cycle,the pathogenic damage effect of the airborne particulate matter on the mice gradually increased.The lung index of the late laying group increased significantly on the 7th day after the treatment(P<0.001),which was 1.73 times that of the control group.The pathological sections of the lungs showed that,compared with the control group,the alveolar wall in the peak laying group was significantly thickened,and the lung pathology in the late laying group was aggravated,with a large number of inflammatory cell infiltration.Compared with the control group,the mRNA expression of interleukin-6(IL-6),interleukin-10(IL-10),tumor necrosis factor-α(TNF-α)and tumor necrosis factor-β(TNF-β)in the alveolar lavage fluid of the late laying group was significantly up-regulated(P<0.01).The expression level of cytokines in serum was consistent with the expression level of cytokine mRNA in bronchoalveolar lavage fluid.The results of this study was of guiding significance for understanding the health effects of environmental particulate matter in laying hen houses on laying hens and breeders,and provided scientific basis for for-mulating prevention and control measures.
different laying periodparticulate matterlung pathologypathogenicitypoultry workers