Ascites Syndrome in Broiler Chickens: A Review on the Aspect of Endogenous and Exogenous Factors Interactions

Increasing susceptibility of broiler chickens to ascites syndrome has coincided with a continuing genetic and nutritional improvement in their feed efficiency and growth rate. Imbalance between oxygen supply and the oxygen required to sustain rapid growth rates and high food efficiencies is believed to be the primary cause of ascites. This imbalance is caused by exogenous and/or endogenous factors. Selection in fast growth broilers, have also resulted in the development of birds with changed anatomical, physiological, metabolic and hematological parameters including thyroid hormone activity, partial pressure of O-2 and carbon dioxide in venous blood, cardiac beta-adrenergic receptors and hematocrit levels that coincide with susceptibility to ascites in broiler chickens. Observations to date have indicated that the structural or endocrine changes are often linked with ascites susceptibility and may be influenced during the early stages of development, embryogenesis and incubation. In this review, particular attention is paid to the interactions between endogenous and exogenous factors as predisposing factors for development of ascites syndrome. Additionally, preventive management procedures like different lighting schedules, feed restriction protocols and supplementation of feed with antioxidants which reduce the incidence of ascites in broiler chickens are highlighted.