Ascites in growing broilers: a research model.

A method was developed to experimentally produce ascites in broiler chickens. High-altitude simulation (treatment group) was conducted to study the development of ascites in broiler chickens. In each of three experiments, 15 male broiler chicks (1 wk old) were placed in a hypobaric chamber (principal groups) for 5 wk and 15 other chicks were reared in batteries (control groups). Ascites occurred among chicks in the principal groups recorded at 13, 27, and 80% at simulated altitudes of 1,980, 2,438, and 2,896 m, respectively. No ascites were observed in the controls at 100 m (the altitude at College Station, Texas). Body weight was significantly (P less than .05) reduced for broilers in the principal groups versus the controls-especially at 2,896 m, where the principals weighed 500 g less than the controls. The counts for hematocrit, hemoglobin, and red blood cells were significantly (P less than .05) increased in all treatment groups; while at 2,438 and 2,896 m, corticosterone was significantly reduced. Histopathology indicated consistent, mild, cardiopulmonary lesions similar to those observed in the spontaneous ascites of broiler chickens. The high-altitude simulation model will be useful in studying the etiological factors and interactions causing ascites.