Pulmonary hypertension, time of exposure to hypobaric hypoxia, pulmonary / body weights ratio in broiler chickens, under temperature controlled conditions

Objective: study the influence of time of exposure to hypobaric hypoxia and pulmonary weight:body weight ratio (PW:CW) on the development of pulmonary hypertension (PH) in Cobb Vantress 500® broiler chickens. Methods: five groups of birds were transfered from a relative normoxic environment (336 masl) to a hypobaric hypoxic one (2638 masl) at the following ages (in days): 6, 10, 15, 20 and 25. An additional group remained at 2638 masl from day 1. All birds were slaughtered at day 49 and the incidence of PH was assessed, as well as PW:CW. Results: no statistical association between age of exposure or PW:CW and PH was found (p<0.05). PH incidence was higher than those previously reported in similar studies. Since there was a strict temperature control in the present study, this factor can be excluded as a possible cause of PH. Further experiments should be conducted to assess the relative impo rtance of other contributing factors in the occurrence of PAH.