Effect of Dietary Modifications Designed to Reduce Early Growth Rate on Live Performance and on Incidence and Severity of Ascites in Two Commercial Broiler Strains When Maintained Under Low Ventilation or Low Temperature Models

Abstract

Two studies were conducted in environmental chambers to evaluate different dietary modifications on the incidence or severity of ascites, leg disorders, and sudden death syndrome in males of tw o commercial broiler strains and their reciprocal crosses. A high energy-high nutrient density diet (HE) series served as the positive control. Two other diet series consisted of a high fiber (HF) diet fed 7 to 21 days of age, followed by the HE series, and a low energy-low nutrient density diet during the early growth phase, as suggested by a major breeder. All diets were pelleted. In one study, a low ventilation model was used while in the second study a low temperature model was used. However, due to limitations of the system we were unable to attain the desired low temperatures. In both studies, however, atmospheric levels of CO and 2 ammonia were greatly elevated. There were no differences in incidence or severity of ascites, leg disorders, or sudden death syndrome among broilers fed the different dietary regimes to 49 days of age. Broilers fed diets designed to reduce early growth rate were significantly lighter than those fed the HE diets at 21 days of age. At 49 days of age body weights were not always significantly different but quantitative weight differences were equal or greater than those observed at 21 days of age. It is possible that under environmental conditions more favorable to the development of ascites that dietary modification may prove beneficial. In these studies, however, live performance was reduced by the dietary modifications with no beneficial effects on reduction of ascites.