H. R. Taheri - Department of Animal Science, Faculty of Agriculture, University of Zanjan, ۴۵۳۷۱-۳۸۷۹۱ Zanjan, Iran.
N. Tanha - Department of Animal Science, Faculty of Agriculture, University of Zanjan, ۴۵۳۷۱-۳۸۷۹۱ Zanjan, Iran.
M. H. Shahir - Department of Animal Science, Faculty of Agriculture, University of Zanjan, ۴۵۳۷۱-۳۸۷۹۱ Zanjan, Iran.

This research was conducted to investigate the effect of inclusion of wheat bran (as a source of insoluble fiber) in a barley-based diet, fed from 11 to 42 d of age, on villus morphology of jejunum, serum cholesterol level, abdominal fat pad and growth performance of broiler chickens. Three hundred and thirty six 10-d-old female Ross 308 chicks were allocated to six diets with four replicates of 14 birds per diet. The diets were a corn-based diet (CN); barley-based diet without (BL) or with multi-enzyme (BL+E, 500 mg/kg of the diet, Rovabio Excel 10%); and barley based-diet that contained 4 (BL+WB4), 8 (BL+WB8) or 12 (BL+WB12) percent wheat bran. Average daily gain, average daily feed intake and feed conversion ratio (FCR) were measured from 11 to 42 d of age. Serum cholesterol level was measured on d 24. Villus height (VH) and villus surface area (VSA) of jejunum, and relative weight (% of body weight) of abdominal fat pad were measured at 42 d of age. The birds receiving CN, BL+E, BL+WB4 and BL+WB8 had significantly (P < 0.01) lower FCR than those feeding on BL. VH (P < 0.01) and VSA (P < 0.001) in the jejunum increased in birds receiving CN, BL+E and BL+WB12 compared with BL birds. Serum cholesterol level in birds fed with BL+WB12 diet decreased (P < 0.05) compared with CN birds. The birds fed with BL, B+WB4, B+WB8, B+WB12 diets showed lower (P < 0.05) relative weight of abdominal fat pad compared with CN diet. In conclusion, the results of this study showed, when broiler chickens fed barley-based diet, the inclusion of lower levels of wheat bran in diet could have a positive effect on feed efficiency, whereas serum cholesterol level, VH and VSA were influenced with the inclusion of highest level of wheat bran.

Barley, broiler, villus morphology, performance, cholesterol, wheat bran