Effect of Processed Cowpeas-Based Diets (Vigna Unguiculata) on Feed Intake and Growth Performance, Protein Digestibility and Ammonia Emission in Broiler Chickens

This research sought to assess the effect of diets made from processed cowpeas on feed consumption and growth performance, protein digestibility, and ammonia emission in broiler chickens.Dehulling, roasting, boiling, dehullingroasting and dehulling-boiling techniques were used to process the cowpea grains.Broiler diets were formulated using soybean, white maize and cowpea meal as ingredients for broiler starter and finisher diets.Cowpea meal was added to the broiler starter and finisher diets at inclusion levels of 10% and 15%, respectively.The diets plans were designed to be iso-proteinous and iso-energetic.Two hundred and ten (210) 1-day-old Cobb 500 broiler chicks were randomly assigned into seven dietary groups using a perfectly randomized design.Each dietary treatment was replicated three times with ten birds per replicate.The dietary treatments included maize-soybean meal (MS), maize-soybean-dehulledboiled cowpea meal (MSDBC), maize-soybean-dehulled-roasted cowpea meal (MSDRC), maize-soybean-dehulledcowpea meal (MSDC), maize-soybean-boiled cowpea meal (MSBC), maize-soybean-roasted cowpea meal (MSRC) and maize-soybean-raw cowpea meal (MSUC).Weekly measurements were taken for average feed intake, weight gain, and ammonia emissions.The feed conversion ratio was determined on a weekly basis.At the conclusion of the experiment, the economic efficiency of each dietary treatment was assessed.Processing improved the nutrient composition of cowpeas.Processing increased crude protein but crude fibre and crude fat were reduced compared to the untreated cowpeas (P<0.05).Feed intake decreased in the MSBC treatment diet, although feed intake from the other treatments was similar to the control diet.There was no difference across all the dietary treatments on body weight gain and feed conversion ratio.The economic efficiency for broilers fed processed cowpea-based diets was higher and ranged from 0.80 to 0.86% and the economic efficiency of broilers fed the control diet was 0.76%.The broilers fed the raw cowpeabased diet had the lowest profit margins (US$0.70 per US$1.00 invested).Processed cowpeas-based diets had no (P>0.05)effect on the digestibility of proteins.The digestibility coefficients of proteins in diets containing processed cowpeas ranged from 54.1 to 65.2% compared to 51.0% of the diet containing raw cowpeas.Processed cowpeas-based diets caused no effect on the amount of ammonia emitted from broiler excreta across all the dietary treatments.Therefore, adding processed cowpeas at inclusion rates of 10% for broiler starter diets and 15% for finisher diets has no effect on feed consumption and growth performance.This practice can enhance protein digestibility, reduce environmental pollution, and support climate-smart agriculture by lowering ammonia emissions from poultry facilities.