Ascites and venous carbon dioxide tensions in juvenile chickens of highly selected genotypes and native strains

摘要: A previous study by this group demonstrated that a high carbon dioxide tension in venous blood (pvCO2) of juvenile broiler chickens is reliable predictor for ascites susceptibility. In new experiment with five highly selected genetic stocks and two resistant old breeds we studied levels variability pvCO2 within each stock at an early age. Effects different selection traits (principally growth rate) between fast growing sire lines slower dam commercial hybrid on gas (pCO2, pO2) tensions, pH haematocrit arterial were examined ages compared to values found breeds. All birds housed floor pens climate controlled room subjected ascites-predisposing cold environment. From stock, 16 the highest (high risk: HRc) lowest (low LRc) 12 days These marked future sampling determine changes haematological characteristics age relate these At day 14, eight non-selected from randomly chosen dissection initial pulmonary pressure index (API) values. Subsequently, all allotted 8 (13 per pen including HRc LRc birds) stock. Production performances 104 measured 33 (feed intake (FI); feed conversion ratio (FCR); body weight (BW) 33). Mortality was recorded during complete experimental period. 5 wk age, necropsied API recorded, which used classify severity syndrome. convincing effect modern confirmed results obtained study. pvO2 much less predictive induced than Hypercapnia combined low followed hypoxemia (inducing values) provoked incidence total absence ascitic symptoms native corresponded unchanged ageing lower pCO2 ages. The difference (mean groups similar irrespective showed no relationship rate. API, as indicator susceptibility, breed correlated values, but not correlation indicated strong will be effective method reduce decisively occurrence syndrome sea level.