The effect of replacing maize with sorghum grain on the performance of broilers was studied. Grain from 4 improved Sorghum bicolor cultivars (CSH 16, CSV 15, PSV 16 and S 35) and one traditional yellow variety were used to replace maize (control diet) in the starter (1-4 weeks) and finisher rations (5-6 weeks) of broilers by 50, 75 and 100% levels. All diets were isonitrogenous and isocaloric and were homogeneous for lysine, methionine and cystine levels. One-day-old 512 commercial Cobb female broilers were divided into 64 groups with 16 dietary treatments and 4 replicates per treatment, with 8 birds in each. In a second trial, sorghum replacement was conducted without homogenizing the diets for nitrogen and energy contents. The study lasted for 6 weeks. It was shown that the liveweight gain and feed intake of broilers was statistically similar in sorghum diets at all inclusion levels compared to the control diet. However, the feed conversion efficiency of broilers in the 100% sorghum diet was significantly higher compared to the maize diet (P=0.05). A better feed conversion efficiency was found with the CSV 15, CSH 16, PSV 16 and the local cultivars at 100% inclusion levels. However, the yellow pigmentation of the skin and carcass of the broilers was better in the maize diet compared to the sorghum diets. Cost varied among and within cultivars at different inclusion levels, and was lower in CSV 15, PSV 16, S 35 and local sorghum cultivar-based diets. Cost was also much lower in CSV 15, PSV 16 and local sorghum cultivars at 100% inclusion level compared to maize. Feed cost per kg liveweight gain was lower with CSV 15 (Rs 17.16) and PSV 16 cultivars (Rs 17.62) compared to maize (Rs 18.02). Although pelleting increased feed costs (by Rs 0.25/kg), it also improved broiler production efficiency compared to mash in sorghum diets. Inclusion of Stylosanthes sp. leaf meal at 3% in 100% sorghum-based diets favourably improved the shank and skin colour of the carcass. Carcass yield and abdominal fat of broilers fed sorghum, sorghum + Stylosanthes sp. and maize diets were similar. In conclusion, the inclusion/replacement of sorghum in maize-based diets and pelleting improves the feed conversion ratio and decreases the total feed costs in broiler production
