Effects of Replacing Soybean Meal with Cowpea Meal on Growth Performance and Carcass Characteristics of Sasso Chickens

Soybean meal is a primary protein source in the poultry feed industry due to its high protein content and good amino acid profile. However, limited supply and high import costs in Tanzania make the cost of commercial feeds high. This study evaluated the effects of replacing soybean meal with cowpea meal on Sasso chickens' growth performance and meat characteristics. Five diets were formulated such that cowpea meal replaced soybean meal by 0 % (T<sub>1</sub>), 25 % (T<sub>2</sub>), 50 % (T<sub>3</sub>), 75 % (T<sub>4</sub>), and 100% (T<sub>5</sub>). A total of 150 one-month-old Sasso chickens with weights ranging from 603.33 ± 10.04 to 618.79 ± 15.30 g were randomly assigned to the five dietary treatments and reared for nine weeks. The amount of feed provided and the refusals were recorded daily and body weight was measured once per week. At the end of the experiment, feed intake, weight gain and feed conversion ratio (FCR) were calculated. In addition, a total of 30 chickens, six chickens per treatment, were randomly selected and slaughtered to determine carcass characteristics. The chickens under T<sub>5</sub> had higher (<I>P </I>≤ 0.001) average feed intake (120.76 ± 1.43 g/d), final body weight (2624.56 ± 62 g), weight gain (1824.37 ± 42.43 g), daily weight gain (31.91 ± 0.90 g/d), slaughter body weight (2592.53 ± 133.73 g) and carcass weight (1988.80 ± 137.00 g) than those on the other treatments. The chickens on T<sub>1</sub> had the lowest values for the same parameters. The FCR ranged from 3.77 ± 0.04 in T<sub>3</sub> to 4.37 ± 0.06 in T<sub>2</sub>. However, the meat of the chickens in T<sub>1</sub> had higher crude protein (21.59 ± 0.71 %) and lower fat contents (10.24 ± 1.19 %) than those in T<sub>5 </sub>(<I>P</I> ≤ 0.05) (18.59 ± 0.82 % CP and 16.60 ± 1.06 % fat). The study concludes that cowpea meal can completely replace soybean meal as an alternative plant protein source in poultry diets.