Abstract
Aim/Background: This study evaluated the effects of enzyme-supplemented sorghum-diluted maize diets on nutrient digestibility and intestinal morphology of broiler chickens. Feed costs account for 60-70% of total broiler production costs, and maize price volatility in Nigeria has driven interest in cost-effective alternatives. Sorghum is an alternative because of its similar energy profile and drought tolerance, but its anti-nutritional factors limit its direct use in poultry diets. Therefore, this study aimed to determine the optimal sorghum inclusion level when supplemented with a commercial enzyme blend.
Methods: The study was conducted in 2025 at the Poultry Unit of the Teaching and Research Farm, Federal University of Technology, Minna, Nigeria. Two-hundred-day-old Cobb 500 broiler chicks were randomly assigned to five dietary treatments in a completely randomised design with four replicates of ten birds each. The experimental diets consisted of 0%, 25%, 50%, 75%, and 100% sorghum replacing maize (T1-T5), formulated to meet nutrient requirements. All diets were supplemented with Birzyme Plus enzyme at 5g per ton of feed. Nutrient digestibility was determined through total excreta collection during days 25 and 51. Two birds per replicate were housed in metabolic cages for 3 days of acclimatisation, followed by 4 days of feeding, with 105g of feed administered per bird daily. Excreta were collected, oven-dried, and analysed for dry matter, crude protein, ether extract, crude fibre, and ash using AOAC (2005) methods. At day 56, two birds per replicate were sacrificed for gut morphology assessment. Data were analysed using one-way ANOVA with SPSS Version 23.0, and treatment means were separated using Duncan Multiple Range Test at P<0.05.
Results: T2 (25% sorghum) achieved the highest dry matter digestibility (17.38% and 17.18% for starter and finisher phases, respectively). Crude protein digestibility was highest in T4 and T3 (17.21% and 16.68%) during the starter phase. The 50% sorghum treatment recorded the highest small intestine weight (2.27%), large intestine weight (2.60%), and liver weight (1.19%). The 100% maize and 50% sorghum groups had the longest small intestines (153.00 cm). The 100% sorghum diet produced the longest absolute gastrointestinal tract (194.00 cm).
Conclusion: The study concluded that enzyme-supplemented sorghum at inclusion levels up to 50% optimises nutrient digestibility and gut development in broiler chickens, providing a cost-effective alternative to maize in poultry production.

Key words: Keywords: broiler, digestibility, enzyme, gut morphology, sorghum