Ammonia affects performance and thermoregulation of male broiler chickens

The effects of various atmospheric ammonia concentrations (X ± S.E.; 16 ± 2; 28 ± 3; 39 ± 4; and 54 ± 5 ppm) at high ambient temperature (Ta = 32 °C) and relative humidity (rh = 60- 65%) on the performance and thermoregulation of male broiler chickens were studied. Body weight declined significantly and proportionally with increasing ammonia concentration in the air. The decline in body weight coincided with a similar pattern in feed intake. Feed efficiency did not differ significantly among treatments, but the broilers exposed to the lowest concentration of ammonia showed the highest feed efficiency. Chickens exposed to the lowest ammonia concentrations regu- lated Tb at significantly lower levels (41.5 °C at 16 ppm and 41.9 °C at 28 ppm) than those at the highest concentrations (42.3 °C at 39 and 54 ppm). Arterial pH increased with increasing ammonia concentration and was similar in the upper 2 concentrations of ammonia. A similar but opposite trend was found in the partial pressure of arterial CO 2 . Plasma triiodothyronine (T 3 ) concentration did not differ significantly among treatments. It can be concluded that exposure to increased ammonia con- centrations impairs broiler performance. It may also be suggested that ammonia can affect the ability of the chickens to control Tb effectively. ammonia / broiler / performance / body temperature / triiodothyronine