1. The aim of the present study was to compare wheat-based diets supplemented with arabinoxylanase, bile acid and virginiamycin with a maize-based diet in their effects on the performance of broilers. 2. The diets were fed to 5 groups of broilers. Group A received a maize-based diet (control), and groups B, C, D and E were fed on wheat-based diets. Diets C, D and E were supplemented with arabinoxylanase (150 mg/kg), bile acid (500 mg/kg) and virginiamycin (200 mg/kg), respectively. 3. A total of 450 1-d-old Ross 385 chicks were randomly divided into 5 groups, each with three pens as replicates (30 birds per pen). The experimental diets were given for 18 d. On d 18, three chickens from each group were slaughtered by cervical dislocation and the liver weight, and duodenal, jejunal and ileal lengths were measured for length and width of the villi and the height of crypts. 4. Arabinoxylanase, bile acid and virginiamycin supplementation significantly increased feed intake and daily gain but had no significant effect on feed conversion ratio. The liver weight was significantly greater in virginiamycin supplemented chicks as compared with those on the diet containing bile acid. 5. Virginiamycin inclusion increased full and empty caeca weight significantly compared with groups A and D. Group A had the lightest caeca. Significant effects of diets were observed on duodenal, ileal and intestinal length, but jejunal length was not affected by diet. The heights of duodenal and ileal, but not jejunal, villi were significantly affected by the treatments. The lengths of villi in groups B and E were significantly higher than other groups. The mean height of ileal villi in group A was significantly higher than in groups receiving the wheat-based diets. The mean width of duodenal and ileal villi was significantly affected by the ration. The height of crypts in group B was significantly higher than in group E. 6. It could be concluded that supplementation of the wheat-based broiler ration with virginiamycin had significant positive effects on gastrointestinal tract characteristics for absorption. Supplementation with bile acid reduced the weight of liver and caeca and the length of duodenum, jejunum, ileum and in small intestine and the height and width of villi.

An experiment was conducted to evaluate the effects of dietary nutrients (protein, methionine, and choline) manipulation on the performance and tibia characteristics of broilers fed diets containing 15% oak acorn. A completely randomized design with five treatments and four replicates of 15 chicks each, was used. One group was fed a diet based on corn (without oak acorn) as control and other four groups were fed diets containing oak acorn with one of the following nutrient manipulation: without nutrient manipulation, high level of methionine (100% more than NRC), high level of CP (10% more than NRC), and addition of 0.2% choline. Starter and finisher diets were fed from one to 21 and 22 to 42 d of age, respectively. The results indicated that group fed diet without nutrient manipulation presented higher feed intake and worse feed conversion ratio (p<0.05) compared with the control group throughout the experiment. Elevated levels of methionine, protein, and choline had significant beneficial effects on feed conversion ratio during starter phase. Feeding oak acorn negatively influenced tibia bone characteristics (bone ash and strength) both at 21 and 42 d of age, whereas the supplementation with protein, methionine and choline prevented those negative effects. In conclusion, dietary inclusion of 15% oak acorn had negative effects on broiler performance and tibia characteristics. Detrimental effects of oak acorn, particularly on tibia bone, were reduced or prevented by increasing the dietary levels of choline, methionine, and protein.