Genome-wide association analysis identifies loci that influence ascites in broilers

Ascites (Pulmonary Hypertension Syndrome) is a metabolic disease in broilers and causes mortality of up to 8% in commercial broilers flocks (Maxwell and Robertson, 1998). Ascites is believed to be caused by an imbalance between oxygen requirement and the cardiovascular ability to supply oxygen (Julian et al., 1987). It has been suggested that the incidence of ascites has increased through the years as a consequence of selection for higher meat yield, increased growth rate and lower feed conversion ratio (Balog et al., 2003, Havenstein et al., 2003). Although extensive research has been performed, the cause of ascites and the association to body weight remains unclear (Decuypere et al., 2000).