Effects Of Ammonia Exposure On Behavior And Immunity Of Broilers And The Flora-Inflammatory Pathway Of Lung Injury Caused By High Ammonia

Ammonia is the most harmful gas pollutant in the broilers breeding environment,which can not be ignored to the growth and health of broilers.In this experiment,the effects of different ammonia concentrations on the behavior,production performance,lung tissue morphology,inflammatory cytokines and neuropeptides of broilers and the effects of high ammonia concentrations on the lung tissue microflora,NLRP3 inflammasome and the flora-inflammation pathway inducing broilers’ lung injury were studied,which provided theoretical basis for the development of healthy breeding of livestock and poultry.This paper mainly studies from two aspects of harm and influence way,the main contents are as follows:1.Effects of different ammonia concentrations on behavior,production performance,lung morphology and cytokine expression of broilersThe experiment used single factor random design,a total of 264 15-day-old male AA broiler chickens,were allotted into four breathing chambers,each chamber contained six cages with eleven birds per cage,and each cage as a replicate.The pre-test period lasted for 7 days and broilers were kept at 28 °C and 60% relative humidity.The formal experiment begins when the broilers were 22-day-old,different ammonia concentrations were introduced into each test group,including control group(0 ppm),15 ppm ammonia group,25 ppm ammonia group and 35 ppm ammonia group.The trial lasted for 21 days.The broilers were slaughtered on the 7th and 21 th day of the experiment respectively.In this study,the performance of broiler was measured,the behavior of broiler was observed,the morphology of lung tissue was observed,the content of inflammatory cytokines IL-1β,IL-6,IL-10 and neurotransmitter NE,5-HT were measured in serum and lung tissue.The results showed that 1)under 7d ammonia exposure,feed conversion was increased significantly at 25 ppm,and daily gain and feed intake were decreased significantly under 35 ppm.However,in the 21 d full-term test,the daily gain only decreased significantly under 25 ppm,the daily feed intake decreased and feed weight ratio increased significantly under 35 ppm ammonia exposure.2)Compared with the control group,15 ppm ammonia exposure significantly increased the head-shaking behavior of broilers.3)The observation of lung tissue morphology showed that red blood cell exudation and inflammatory cell infiltration would occur when exposed to 15 ppm ammonia,and local lobular tissue hyperplasia would occur when the ammonia concentration reached 35 ppm.4)Under 7d ammonia exposure,IL-1β in lung tissue and serum of25 ppm group increased significantly,while IL-10 in serum of 35 ppm group increased significantly.However,under 21 d ammonia exposure,IL-10 increased significantly in 15 ppm group,while IL-1βand IL-6 increased significantly only in 35 ppm group.5)Neuropeptide measurement showed that the content of 5-HT in lung tissue decreased significantly under 35 ppm ammonia exposure.In conclusion,15 ppm low ammonia concentration will have a negative impact on broilers,and with the increase of ammonia concentration,the harm will increase.2.Research on flora-immune inflammatory pathway of high ammonia exposure on lung tissue injury in broilersThe experiment used single factor random design,a total of 132 15-day-old male AA broiler chickens,were allotted into four breathing chambers,each chamber contained six cages with eleven birds per cage,and each cage as a replicate.The pre-test period lasted for 7 days and broilers were kept at 28 °C and 60% relative humidity.The formal experiment begins when the broilers were 22-day-old,broilers were divided into two groups: control group and 35 ppm ammonia group.The trial lasted for 21 days.At the 7th and 21 th day of the experiment,three close to average weight broilers were selected for each replicate.After slaughtering,the respiratory tract flora and NLRP3 inflammasome were measured.The effects of high ammonia on respiratory tract diseases were studied through the relationship between respiratory tract flora,NLRP3 inflammasome and inflammatory factors.For this,we validated the occurrence of lung tissue inflammation under ammonia exposure and detected the lung tissue microbial constituent by 16 S rDNA sequencing.Moreover,the relative expression levels of NLRP3,caspase-1mRNA and the content of IL-1β,IL-6 were measured.After 7d ammonia exposure,the proportion of the phylum Proteobacteria and the genus Escherichia/Shigella in lung tissue were significantly increased,the expression levels of NLRP3 and caspase-1 mRNA were significantly increased,and the content of IL-1β in lung tissue and serum were higher than the control group.In conclusion,high ammonia induced lung tissue inflammation via increasing the proportion of Escherichia/Shigella,activating NLRP3 inflammasome and promoting IL-1β release.These findings provided a reference for the prevention and control of respiratory tract diseases in humans and animals caused by ammonia pollution.In conclusion,1)Head-shaking behavior can be used as an early sensitive response to the degree of lung injury and production performance changes caused by ammonia exposure in Broilers;2)15 ppm ammonia causes behavioral abnormality and lung injury in 3-6 week-old broilers,25 ppm ammonia causes feed intake decrease and lung tissue inflammation in 3-6 week-old broilers,35 ppm ammonia reduces production performance,and causes lung tissue hemorrhage and inflammatory injury in 3-6week-old broilers.3)Exposure to high ammonia concentration of 35 ppm significantly increased the proportion of Escherichia/Shigella genus in the lung tissue of 3-6 week-old broilers,which led to the release of a large number of inflammatory factors through the microflora-NLRP3 inflammatory pathway,and finally led to the occurrence of inflammatory damage in the lung tissue.