Several negative conditions affect broilers intestinal health and reduce their performance. Feed additives, called growth promoters, are used in broilers production to control enteric problems, but is very difficult to evaluate these products in experimental conditions. The aim of this study was to evaluate the best experimental model to induce enteritis in broilers. A 192 one-day-old male broilers (Cobb 500®) were divided into 2x4 a factorial design (with good or poor quality oil in diet and with or without coccidiosis and Gumboro disease vaccine), with eight treatments. The birds were housed on litter, with water and feed ad libitum and were weighed weekly. At days 14, 21, 28 and 35, six birds per treatment were euthanized and gut gross lesions evaluated. Samples of duodenum, jejunum and ileum were taken for histopathological evaluation. A standard lesion score considering lymphocytic infiltration, enterocytes morphology, interstitial edema, and lymph vessel dilation was used. It was observed that broilers fed with poor quality of oil in the diet showed lower body weight and more severe macroscopic and histopathologic lesions on all intestinal segments. These lesions were more severe in birds challenged with coccidiosis and Gumboro disease. The results suggest that an inclusion of poor quality of oil in diet, associated with challenge with coccidiosis at first day and Gumboro virus vaccine at 16 day is the best protocol to promote enteritis in broilers at experimental conditions, and that use of standard lesion score was useful to evaluate enteritis.
Enteritis; experimental protocol; standard score of lesions; histopathology; broilers
