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 importance of other contributing factors in the occurrence of pah.