Effect of Acacia angustissima Leaf Meal on the Physiology of Broiler Intestines

The effect of A. angustissima leaf meal based diets on intestinal physiology and dressed carcass weight was investigated on 150 day old chicks. Three diets, 0, 5 and 10% A. angustissima were used in a three phase feeding programme. At days 14, 28 and 42, two birds from each replicate were slaughtered, dressed and weighed. The weights and lengths of the duodenum, jejunum and colon were measured. Approximately 1 cm specimen was taken from each organ, fixed in formalin and stained for histological analysis. Using a light microscopy, the digestive and absorptive properties of the tissues were assessed. Inclusion of A. angustissima leaf meal increased intestinal wall thickness, epithelial thickness, and villus height of the duodenum (P < 0.05). There was no effect on the proportional weight and length of the jejunum, jejunum villi height and villi width (P > 0.05) but jejunum wall thickness decreased with increasing levels of the leaf meal (P < 0.05). Leaf meal inclusion resulted in an increase in weight, intestinal wall and mucosal thickness of the colon (P < 0.05) and a decline in sub-mucosal fold height and haustra coli width of the colon (P < 0.05). Dressed weight was the same across diets at two weeks (P > 0.05). At four and six weeks, broilers on the control and 5% diet had superior dressed weights to the 10% fed broilers (P < 0.05). It was concluded that for intestinal physiological adaptation that will not compromise weight gain in broilers, up to 5% A. angustissima could be included in broiler diets.