Investigation Of Ammonia Content In Chicken Farms In A Certain City And The Effect Of Ammonia On Broiler Performance And Spleen Tissue Damage

Ammonia(NH₃)is a colorless and irritating gas,which is mainly composed of nitrogen and hydrogen.In livestock breeding,ammonia is the most important harmful gas produced in poultry houses.The manure of livestock and nitrogen-containing feed can be decomposed to produce a large amount of ammonia gas,which will not only affect the immunity of livestock,but also affect the productive performance,increase the probability of disease and serious harm to the health of breeders.If ammonia is discharged into the air,it will also cause air pollution,increase the formation of PM 2.5 particles,and affect human health.China ammonia emissions account for the total amount of ammonia in the forefront of the world,including ammo nia produced animal husbandry proportion of China's total ammonia emission maximum.Ammonia has a serious impact on the livestock industry.Especially in winter in northern areas,there are excessive ammonia gas in many chicken houses.High concentrations of ammonia affect the health of livestock and poultry and cause serious economic losses to the breeding industry.In order to evaluate the current status of ammonia pollution in broiler houses in winter in a city of Liaoning Province and its effect on production performance of chicken,and to clarify the mechanism of ammonia damage to broiler spleen tissue and the effect of microecological agents on ammonia concentration in chicken houses,in this experiment,the ammonia gas detector was used to epidemiological investigate the ammonia concentration in the chicken house of a broiler farm in Liaoning,and the ELISA method was used to detect the antibody level of the Newcastle disease and count the survival rate,feed-to-gain ratio,average weight and European index.With reference to the actual ammonia concentration surveyed,an environmental control warehouse was used to establish a broiler ammonia exposure model.120 1-day-old healthy chicks were randomly divided into control group,low ammonia group and high ammonia group,and each group contained 40chickens,each group repeated 4 times,each repeated 10 chickens.When broilers were 0 to 3weeks old,the ammonia concentration in the control group,low ammonia group,and high ammonia group were 5,10,and 20 mg/m³,respectively.When broilers were 4-6 weeks old,the ammonia concentration in the house were 5,15 and 45 mg/m³.When the broilers were raised to 42days of age,the weight was measured,survival rate,feed-to-gain ratio,average body weight and European index were calculated.The broilers were killed and sampled,and the serum was used to determine the level of Newcastle disease antibodies,weigh the immune organs and calculate the immune organ index.Using H.E staining,transmission electron microscopy,TUNEL,fluorescence quantitative PCR and Western blot,the morphological changes of the spleen were observed,and the expressions of mitochondrial fusion and split genes(Mff,Mfn1,Mfn2,Opa1,and Drp1),glucose metabolism-related genes(ACO2,PFK,PK,HK1,HK2,SDHB,LDHA,and LDHB),cell apoptosis and related genes(Bax,Bak,Bcl-2,P53,Caspase 3,Caspase 9,and Cyt-C),inflammatory factors(TNF-?,COX-2,i NOS,PTGE,and NF-?B),cytokines(IL-1?,IL-2,IL-4,IL-6,IL-10,and IFN-?),heat shock protein genes(Hsp90,Hsp70,Hsp60,Hsp40,and Hsp27)were detected.Finally,we used a group comparison method to evaluate the effects of microecological agents on the ammonia concentration,Newcastle disease antibody levels and production performance in the house.The results showed that:(1)In the broiler farm of a city in Liaoning Province,the over-standard rate of the ammonia concentration in winter was 33.33%,and the maximum ammonia concentration was 36.8 mg/m³.(2)The results of the flow adjustment and the test showed that the qualification rate of Newcastle disease antibody,survival rate,average weight and European benefit index were all negatively correlated with ammonia concentration,and the feed-to-gain ratio was positively correlated with ammonia concentration.It was proved that ammonia affects the level of Newcastle disease antibody and production performance in broilers.(3)After exposure to ammonia gas,H.E staining revealed that the boundary between the red and white pulp of the spleen tissue was unclear,the trabecula swelled,lymphocytes and macrophages infiltrated,and neutrophils increased.The expression of inflammation-related factors(NF-?B,COX-2,i NOS,PTGE,TNF-?,and IL-1?)were up-regulated,which confirmed that ammonia exposure caused inflammatory response(4)After exposure to ammonia gas,the expression of Th2 markers IL-4,IL-6,and IL-10 was increased,and the expression of Th1 markers IFN-?and IL-2 was decreased,which confirmed that ammonia exposure caused the imbalance between Th1 and Th2 in the cell.(5)Observation using transmission electron microscope revealed that the spleen tissue nuclei shrank,chromatin agglomerated and edged,mitochondria swelled,cristae fractured,and vacuolated.The TUNEL analysis results showed that the apoptosis rate of spleen tissue cells increased with the increase of ammonia exposure concentration.Meanwhile,in the ammonia exposure group,the m RNA expression of mitochondrial fusion genes(Drp1 and Mff)was increased,the m RNA expression of mitochondrial division genes(Opr1,Mfn1,and Mfn2)was decreased,the m RNA expression of glucose metabolism related genes(ACO2,PFK,PK,HK1,HK2,SDHB,LDHA,and LDHB)was decreased,the expression of apoptosis-related genes(Bax,Bak,P53,Caspase 3,Caspase 9,and Cyt-C)was increased,and the expression of Bcl-2 was decreased,showing a dose-effect relationship,indicating that ammonia exposure can cause mitochondrial dynamics imbalance to induce apoptosis.(6)Ammonia exposure caused up-regulation of m RNA expression of Hsp90,Hsp70,Hsp60,Hsp40,and Hsp27,and up-regulation of protein expression of Hsp90,Hsp70,and Hsp60,showing a dose-effect relationship,indicating that heat shock proteins were involved in spleen tissue damage caused by ammonia exposure.(6)After using the microecological preparation in the chicken farm,compared with the control group,the ammonia content in the chicken house of the experimental group decreased by80.96%,the level of Newcastle disease antibody in broilers increased by 4.6%,the average feed-to-weight ratio decreased by 0.04 kg,and the survival rate increased 1.63%,the European index increased by 32.44.These results showed that microecological preparation can reduce ammonia in the chicken house,improve the level of Newcastle disease antibody and production performance of broilers.In summary,this study confirms that the over-standard rate of the ammonia concentration in the broiler farm in a certain city in Liaoning Province in winter is 33.33%,and long-term ammonia exposure can reduce broiler performance.Ammonia exposure can cause the damage to the mitochondrial structure of the spleen,disturbance of energy metabolism,induction of cell apoptosis.Meanwhile it can cause the Th1/Th2 imbalance in the sp leen to trigger an inflammatory response and cause a decrease in the level of Newcastle disease antibodies.Microecological preparations can effectively reduce the concentration of ammonia in the broiler farm,increase the level of antibodies,and improve the performance of broilers.This experiment provides a basis for enriching ammonia toxicology research and provides a reference for the prevention and control of ammonia in chicken farms.