Submitted to: Avian Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 9, 2005
Publication Date: March 1, 2006
Citation: Miles, D.M., Miller, W.W., Branton, S.L., Maslin, W.R., Lott, B.D. 2006. Ocular responses of ammonia in broiler chickens. Avian Diseases. 50:45-49.
Interpretive Summary: Atmospheric ammonia inhibits broiler performance. Quantified effects are based on older genetic stock with a seven-week body weight of 2000 g compared to 3200 g today. To assess the impact on present day broilers, two trials were conducted exposing broilers to graded levels of aerial ammonia 0, 25, 50, and 75 ppm. Sixty, day-old chicks were placed in environmentally controlled chambers, group weighed weekly, and processed with yield determined at 7 weeks of age. Final body weight was depressed by 6% and 9% for the 50 and 75 ppm concentrations as compared to the 0 ppm ammonia level. Yield differences were not statistically supported. Though current genetic stock reaches growout weights approximately 60% greater than two decades ago, relative quantified effects of ammonia exposure were similar. Additionally, statistical analysis of the results provided a simple equation for predicting body weight decline of male broilers for ammonia exposure.
In two trials, 60 male commercial broilers were placed in each of eight environmentally controlled chambers receiving 0, 25, 50 or 75 ppm aerial ammonia from 1 to 28 d. Birds exposed to 0 and 25ppm (lower concentrations) ammonia gas developed ocular disease, but at a slower rate when compared to birds exposed to 50 and 75ppm (higher concentrations). Birds exposed to higher concentrations developed more severe ocular disease. With little atmospheric ammonia present in the grow-out stage, the damaged broiler corneas healed. Lymphocytic and heterophilic infiltrates in the iris at 49 d followed corneal and anterior chamber damage from 7 to 49 d of age as observed by ophthalmic examination. The lower ammonia concentrations resulted in abnormalities that were slight when compared to the damage at the higher ammonia concentrations at 50 and 75ppm. As measured by the degree of inflammatory infilitrates, respiratory tract tissues did not appear to be affected negatively affected by the graded treatment levels of aerial ammonia. The findings in this investigation represent the first report of ammonia-induced uveitis in chickens.