Age‐related effects of varying ammonia concentrations on hematophysiological variables in broiler chickens,

This study examined the response of different aged birds of the same genetic strain exposed to ammonia at set concentrations on blood physiological variables under environmentally controlled conditions. The experiment consisted of 4 levels (0, 25, 50 and 75 ppm) of ammonia concentrations and 4 different ages (1‐day, 7‐days, 14‐days and 21‐days) arranged in a complete randomized factorial design. Venous blood samples were collected at the end of each 7 days of ammonia exposure. Partial pressure of CO 2 (pCO 2 ), pH, hematocrit (Hct), and hemoglobin (Hb) increased significantly (P = 0.05), whereas partial pressure of O 2 (pO 2 ), bicarbonate (HCO 3 − ), and K + decreased with increasing ammonia concentration compared with 0 ppm. In addition, pO 2 , pCO 2 , HCO 3 − , Hct, Hb, Na + , and anion gap (Angap) increased significantly (P = 0.05), while pH, glucose, and corticosterone decreased as bird's age increased. Ammonia × age interactions were observed for pH, anion gap, and HCO 3 − . There was significant main effect of age but not that of ammonia on plasma corticosterone concentrations. The main effect of age was more pronounced than that of ammonia on examined variables. These conditions improved as the age of birds increased from 1‐d to 21‐d old. It was concluded that different aged birds of the same genetic strain respond differently to set ammonia concentrations and younger birds have a more intense reaction to the ammonia than older birds.