Abstract
Simple SummaryAmmonia is the dominant pollutant gas in poultry houses, and it is harmful to broilers, especially in the cold season. Exposure to ammonia leads to damage to the respiratory system of broilers, affects the health of broilers, and reduces production performance. To date, the relationship between lung flora and immune system and brain exposed to ammonia is unclear, and there have been numerous studies on the lung–brain axis in recent years. Therefore, the aim of this study is to explore the effects of ammonia on lung microflora, lung tissue mucosal morphology, inflammatory cytokines, and neurotransmitters. Moreover, exploring these mechanisms can help in the development of strategies that alleviate the negative effects of the performance of ammonia. Our study suggests that the damage caused by ammonia to broiler lungs may be mediated by the lung–brain axis.Atmospheric ammonia is one of the main environmental stressors affecting the performance of broilers. Previous studies demonstrated that high levels of ammonia altered pulmonary microbiota and induced inflammation. Research into the lung–brain axis has been increasing in recent years. However, the molecular mechanisms in pulmonary microbiota altered by ambient ammonia exposure on broilers and the relationship between microflora, inflammation, and neurotransmitters are still unknown. In this study, a total of 264 Arbor Acres commercial meal broilers (21 days old) were divided into 4 treatment groups (0, 15, 25, and 35 ppm group) with 6 replicates of 11 chickens for 21 days. At 7 and 21 D during the trial period, the lung tissue microflora was evaluated by 16S rDNA sequencing, and the content of cytokines (IL-1β, IL-6, and IL-10) and norepinephrine (NE), 5-hydroxytryptamine (5-HT) in lung tissue were measured. Correlation analysis was established among lung tissue microflora diversity, inflammatory cytokines, and neurotransmitters. Results showed that the broilers were not influenced after exposure to 15 ppm ammonia, while underexposure of 25 and 35 ppm ammonia resulted in significant effects on pulmonary microflora, inflammatory cytokines, and neurotransmitters. After exposure to ammonia for 7 and 21 days, both increased the proportion of Proteobacteria phylum and the contents of IL-1β and decreased the content of 5-HT. After exposure to ammonia for 7 days, the increase in Proteobacteria in lung tissue was accompanied by a decrease in 5-HT and an increase in IL-1β. In conclusion, the microflora disturbance caused by the increase in Proteobacteria in lung tissue may be the main cause of the changes in inflammatory cytokines (IL-1β) and neurotransmitters (5-HT), and the damage caused by ammonia to broiler lungs may be mediated by the lung–brain axis.
Highlights
Ammonia is one of the poultry house by-products that are detrimental to broilers and is produced from uric acid and undigested proteins in manure by aerobic or anaerobic bacteria [1]
In this study, we investigated the effects of different concentrations of ammonia on lung tissue mucosal morphology, microflora, inflammatory cytokines, and neurotransmitters of broilers by exposure to ammonia for 7 days and 21 days, and we analyzed the relationship between lung tissue microflora diversity, inflammatory cytokines, and neurotransmitters
After 7 days of ammonia exposure, compared with the control group, inflammatory cell infiltration occurred in the 15 ppm group, local tissue hemorrhage occurred in the 25 ppm group, and a large number of red blood cells and necrotic cell masses were observed in the bronchus in the 35 ppm group
Summary
Ammonia is one of the poultry house by-products that are detrimental to broilers and is produced from uric acid and undigested proteins in manure by aerobic or anaerobic bacteria [1]. The ammonia concentration in the poultry houses should not exceed 25 ppm. Several studies reported that 25 ppm ammonia can reduce productive performance, amplify immune response [4], and damage the respiratory system [5], leading to low breast muscle and carcass composition in broilers [6]. When ammonia concentration reaches 50 ppm, it can even affect the eyes, causing cornea damage and blurred vision, leading to difficulties in food foraging, which affect the metabolism and performance of broilers [7]. There is evidence suggesting that bacteria may have an impact on the host physiology by regulating neurotransmitters such as dopamine, norepinephrine, serotonin, or gamma-aminobutyric acid (GABA) [13]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
