Effect of Mannanase on Varying Levels of Guar Korma Meal in Broilers

Guar korma meal (GKM), a byproduct of the guar gum industry, has emerged as a potential alternative protein source in poultry nutrition, particularly in the subcontinent. This study evaluated the effects of graded inclusion levels of Guar Korma Meal (GKM), with and without mannanase enzyme supplementation, on the growth performance of broiler chickens. A total of 2,000 day-old mixed broiler chicks (Arbor Acre Plus) were allocated to eight dietary treatments in a completely randomized design with a two-way factorial arrangement (4 GKM inclusion levels × 2 enzyme levels), each with five replicates of 50 birds. Diets were formulated with GKM inclusion at 0%, 2.5%, 5%, and 7.5%, replacing soybean meal, with or without mannanase supplementation (200 g/ton). Growth performance parameters feed intake (FI), body weight (BW), feed conversion ratio (FCR), and mortality were recorded at 14, 28, and 42 days. Across the starter, grower, and finisher phases, increasing GKM inclusion up to 7.5% had no significant effect (P > 0.05) on FI, BW, FCR, or mortality. Mannanase supplementation significantly improved FI and FCR during the starter phase (P < 0.05) but had no significant effect during the grower or finisher phases. A significant GKM × mannanase interaction (P = 0.01) was observed for starter-phase FCR, indicating that enzyme response varied with GKM inclusion level. These findings demonstrate that GKM can effectively replace soybean meal at inclusion levels up to 7.5% without compromising broiler growth performance, with mannanase offering additional early-life benefits. This supports GKM as a viable, cost-effective alternative protein source for broiler diet formulation, particularly in regions facing soybean meal price volatility and import dependence.