Evaluation of different dietary treatments to reduce ascites syndrome and their effects on corporal characteristics in broiler chickens

Four dietary treatments were applied to sexed broiler chickens to evaluate ascites syndrome (AS), mortality, and corporal composition using productive parameters, corporal characteristics, and carcass yield to derive profit-cost relationships. One-day-old broiler chicks (2,200 males and 2,200 females), from a commercial strain, were assigned to eight groups of 550 birds each. These groups were distributed among four dietary treatments: 1) feeding ad libitum with a high-density diet, 2) feeding ad libitum with a low-density diet, 3) feeding ad libitum with a high-density diet from 1 to 14 d of age and from 15 to 52 d of age with the same diet for consumption 8 h/d, 4) high-density diet at 90% feed consumption as in Treatment 1 through 52 d of age. Treatments 3 and 4, with feed restriction, resulted in lower mortality rates than Treatments 1 and 2. The highest mortality was in males. The best weight gain was achieved in Treatments 1 and 2 (P < 0.05), whereas Treatments 3 and 4 resulted in the best feed conversion. For measured corporal characteristics, the main effect, sex, resulted in significantly different (P < 0.01) intestine, liver, abdominal fat, and carcass weights; length of tibia; yellowness of skin; and lengths of the duodenum to Meckel's diverticulum and Meckel's diverticulum to rectum (P < 0.05). The main effect, dietary treatment, was significantly different (P < 0.01) only for the yellowness of the skin. The interaction between the two main effects was significant (P < 0.05) for the intestine and carcass weights. Males exceeded females in carcass weight but not in the breast weigbt/carcass weight ratio. Treatments 1 and 2 resulted in the best carcass yield but Treatment 4 resulted in the best profit-cost relationship, the lowest mortality due to AS, the best feed conversion, good corporal composition with good pigmentation, and increased economic benefits in sale systems, live birds, and carcass sale.