Ileal Villi Morphological Characteristics of Cobb 500 Broilers Fed Phytase and Tannase Treated Sorghum Based Diets

Abstract

The effects of phytase and tannase enzyme treatment of sorghum-based broiler diets on ileal villi characteristics were evaluated in Cobb 500 broilers. A total of three sorghum levels, 0, 50, and 100%, with 4 enzyme levels; 0, 5% phytase, 5% tannase and 5% phytase+tannase combination were used to develop 12 different dietary treatments. Three hundred and sixty broilers were randomly allocated to the 12 dietary treatments in a completely randomized design experiment. On day 42, two birds from each replicate were randomly selected and slaughtered for ileal villi morphometry analyses. A 2cm tissue sample of the ileum was cut and prepared for histological analyses. Villus height and width, muscularis externa thickness, and crypt depth were measured on a light microscope using a calibrated eyepiece graticule. The total villi surface area was calculated, which indicates the digestive and absorptive capacity of the ileum. The General Linear Models (GLM) procedure of the Statistical Analysis System ver 9.4 (SAS Institute Inc., 2011) was used to analyse the data. All tests were performed at p < 0.05 significance. Villus height, width, and muscularis externa thickness significantly increased with increasing levels of sorghum in the diet (p<0.001). Birds fed complete sorghum diets supplemented with phytase enzyme had the longest villi (p<0.001). The 0% and 100% sorghum levels exhibited comparable crypt depth. Treatment significantly affected the apparent villi surface area (p<0.0001). The apparent villi surface area increased with increasing sorghum inclusion. Birds fed a complete sorghum diet supplemented with phytase had the highest villi surface area (15.48±0.241 mm). It can be concluded that phytase and tannase can be added to complete sorghum broiler diets without compromising ileal villi integrity. Hence, we recommend the addition of phytase and tannase in sorghum-based broiler diets to counteract the effects of sorghum antinutrients.