Effects of whole-grain paddy rice replacement with or without enzyme addition on broiler performance and intestinal...

To investigate the effect of replacing maize with whole-grain paddy rice (WPR) in broiler chicken diets, with or without enzyme addition, on growth performance and histological structures of the intestinal villi, 14-d-old Marshall Chunky male chicks were divided into 4 groups with 4 replicates of 4 chicks each. The experimental diets containing different concentrations of WPR were as follows: (1) 0 g/kg (Control); (2) 141.5 g/kg, grower, and 125.0 g/kg, finisher (25WPR); (3) 283.0 g/kg, grower, and 250.0 g/kg, finisher (50WPR); (4) 283.0 g/kg, grower, and 250.0 g/kg, finisher, and enzyme supplementation (50WPR + enzyme). All diets were formulated to be isocaloric and isonitrogenous and provided ad libitum for 35 d. There were no differences among the diets on the growth performance and digestive organ size. The villus height and cell mitosis number of all intestinal segments did not change in any treatment. The ileal villus area, duodenal cell area, duodenal and jejunal goblet cell number in the 50WPR group increased significantly relative to the control but not when enzyme was included. In the scanning electron microscope results, all experimental groups showed clear protuberant cells and cell clusters on the villus apical surface of the duodenum. In the jejunum, cell clusters and areas having cells with no microvilli were frequently found in both the 50WPR and 50WPR + enzyme groups. In conclusion, broilers fed on diets replacing maize with WPR showed hypertrophied villi of duodenum and ileum and epithelial cells in duodenum and jejunum, especially in the 50WPR group, without negatively affecting growth performance. These findings suggest that WPR can replace maize up to a level of 50% (283.0 g/kg, starter, and 250.0 g/kg, finisher) in broiler diets without enzyme supplementation. However, further studies are needed to improve our knowledge of the influence of WPR on higher numbers of birds.