| In order to provide theoretical basis for scientifically regulating the hygiene and reducing the emission of harmful gas in pig houses,the experiment was carried out to study the distribution of ammonia,hydrogen sulfide and carbon dioxide in the farrowing house,and the effect of ammonia on piglet respiratory organs was further explored.This study consisted of two experiments.Experiment 1:the harmful gas,temperature and humidity of 5 positions and 3 heights on the same horizontal was monitored automatically and continuously in the semi-closed farrowing houses of piggery in Taigu for 7 days;Experiment 2:a total of 12 Du grown and crossbred weaned pigs with similar weight were selected,which were randomLy divided into 4 groups,3 pigs of each group,and the pigs were exposed to ammonia with the concentration of 7 ppm,30 ppm,60 ppm and 90 ppm for 8 hours of daily continuous stimulation,respectively.The experimental periods were 15 days with 3 days of adaptation,11 days of experiment and followed by 1 day of data collection.The blood was collected before morning feeding on the 15th day,and lungs and trachea were also collected after slaughtering the pigs.The tissue morphology of the trachea and lung were determined by the tissue and electron microscopy technique,and the expression quantities of gene of the closely linked protein claudinl,caspase3 and tracheocogene muc5ac were determined by real-time fluorescence quantitative method.The result showed that:①The concentration of ammonia,hydrogen sulfide and carbon dioxide in the daytime was lower than that in the evening,but the change trend of these gas was consistent in a day.②There is a difference of the gas concentration in spatial distribution.The gas concentration around the farrowing house was higher than that in the middle.The ammonia concentration decreased from the ground to the roof,and the vertical hydrogen sulfide concentration was higher in 1.5 m than that in 3.1 m.③ Both ammonia and carbon dioxide were significantly correlated with temperature and humidity(r=0.898 and r=0.945,P<0.05,respectively).④The morphology of the trachea and lung tissues of piglets were damaged to varying degrees,the mucosal cilia of the trachea were detached,the squamous epithelial cells were proliferated,the alveoli ruptured into vacuoles,and the alveolar septum was thickened.⑤Transaction ammonia concentration above 30 ppm significantly reduced claudinl mRNA expression in the trachea and lung tissues of piglets(P<0.05).⑥The influenced extent of the caspase3 by ammonia was higher in the lung tissue than that in the trachea,ammonia concentration was 60 ppm only increases the content of caspase3 in lung tissue(P<0.05),and ammonia concentration to 90 ppm increase caspase3 expression in the lung and trachea(P<0.05);The expression of muc5ac mRNA in trachea was significantly increased when the concentration of ammonia was higher than 60 ppm(P<0.05).Levels of IL-2 in serum,trachea and lung tissues of piglets were significantly reduced when concentrations of methanol above 30 ppm(P<0.05),and levels of IL-6,ill-diluted 1,inf-plated and IL-10 were significantly increased(P<0.05).Conclusion:①the ammonia concentration in the middle of the farrowing house was lower than that in the around,and the concentration from the ground to the roof decreases gradually.Ammonia and carbon dioxide concentration were positively correlated with indoor temperature and humidity.②The ammonia concentration of 30 ppm can damage the morphological structure of trachea and lungs,and affect the content of cytokines in serum,trachea and lung tissues,and cause tissue inflammation.③ When the concentration of ammonia reaches 60 ppm,the airway mucus secretion increased.④ The ammonia concentration of 90 ppm would cause apoptosis of tissue cells.In conclusion,the distribution of harmful gas is imbalanced in piggery,ammonia could destroy the respiratory tract mucous membrane of the piglet,and cause inflammation and decreased immunity,reducing the temperature and humidity can decrease the concentration of ammonia in the piggery. |
