Effects of crude cowpea (Vigna unculata) meal supplemented with enzyme on nutrient digestibility and growth performance of broiler chickens

This study was designed to assess the digestibility of feed components and the growth performances of broilers fed on raw Cowpea based diet supplemented with fibrolytic enzyme (Naturzyme®). A control ration without Cowpea and enzyme was compared to six others rations in which raw cowpea was incorporated at 15 and 25% and supplemented with 350 and 500g enzyme/ton of feed. The experimental rations were randomly assigned to 252 twenty-one-day old Cobb500 broiler chickens in a 2x2 factorial design (two level of enzyme and two level of cowpea). At 49 days old, faeces were collected over a period of 3 days to assess the digestibility of feed components. The main results showed that the increasing rate of raw cowpea in the rations induced a linear decrease (p<0.05) in feed intake. The inclusion of 25% of cowpea in the ration irrespective of the rate of incorporation of the enzyme tends to increase the digestibility of feed component as compared to the control. Growth parameters of broilers inversely decrease with the incorporation rate of raw cowpea in the ration. The highest carcass yield (p<0.05) was recorded with 15% raw cowpea supplemented with 500g of enzyme per ton of feed. The relative weight of the gizzard increased significantly (p<0.05) with the increasing incorporation rate of raw cowpea in the diet with or without enzyme supplements. In conclusion, raw cowpea supplemented with enzyme did not substantially improve the growth performance of broilers. Other processing methods like boiled or fermented should be considered for better utilization of cowpea in broilers diet.