In-house ammonia induced lung impairment and oxidative stress of ducks

Ammonia (NH3) is a toxic gas that in intensive poultry houses, damages the poultry health and induces various diseases. This study investigated the effects of NH3 exposure (0, 15, 30, and 45 ppm) on growth performance, serum biochemical indexes, anti-oxidative indicators, tracheal and lung impairments in Pekin ducks. A total of 288 1-day-old Pekin male ducks were randomly allocated to four groups with 6 replicates and slaughtered after the 21-day test period. Our results showed that 45 ppm NH3 significantly reduced the average daily feed intake (ADFI) of Pekin ducks. NH3 exposure significantly reduced liver, lung, kidney, and heart indexes, and lowered the relative weight of the ileum. With the increase of in-house NH3, serum NH3 and uric acid (UA) concentrations of ducks were significantly increased, as well as liver malondialdehyde (MDA), Superoxide dismutase (SOD), and glutathione peroxidase (GPX-Px) contents. High NH3 also induced trachea and lung injury, thereby increasing levels of tumour necrosis factor-α (TNF-α) and interleukin-4 (IL-4) in the lung, and decreasing the mRNA expressions of zonula occludens 1 (ZO-1) and claudin 3 (CLDN3) in the lung. In conclusion, in-house NH3 decrease the growth performance in ducks, induce trachea and lung injuries and meanwhile increase the compensatory antioxidant activity for host protection.