Strategic use of β-mannanase and xylanase β-glucanase preparation in maize-based diets to improve broiler performance

Poultry feed contains significant amounts of undigested components, driving the search for innovative strategies to improve their utilization. This study aimed to evaluate the effects of β-mannanase, alone or in combination with a xylanase and β-glucanase preparation (XG), on growth performance, nutrient and energy utilization, and the gastrointestinal environment of broilers fed maize-based diets. A total of 384 mixed-sex Cobb 500 d-old broilers were assigned to 4 treatments for 35 days in a 2 × 2 factorial arrangement, with β-mannanase (with or without) and XG (with or without) as factors. Each treatment included eight replicate pens of 12 birds each, totalling 96 birds per treatment. During d 0 to 10, dietary supplementation of β-mannanase increased weight gain (P = 0.009) and improved feed conversion ratio (FCR) (P < 0.001) compared to the unsupplemented control. During d 11 to 21, β-mannanase improved FCR (P = 0.039), and β-mannanase and XG interacted for weight gain (P = 0.008), where β-mannanase or XG alone increased weight gain compared to the unsupplemented control but there were no further improvements achieved via their simultaneous use. During d 22 to 35, XG supplementation increased weight gain (P = 0.003) and improved FCR (P = 0.032). During d 0 to 35, XG improved FCR (P = 0.019), and XG and β-mannanase tended to interact for FCR (P = 0.071), with either of the enzymes improving FCR compared to the unsupplemented control but with no further improvements when added in tandem. During d 0 to 35, XG and β-mannanase interacted for weight gain (P = 0.026), where XG improved weight gain in the absence of β-mannanase but there were no further improvements achieved via their simultaneous use. Dietary β-mannanase increased total tract retentions of dry matter (P = 0.001), insoluble non-starch polysaccharides (NSP, P = 0.010), total NSP (P = 0.010), calcium (P = 0.020), apparent metabolizable energy (AME, P < 0.001) and nitrogen-corrected AME (AME_n, P < 0.001). Dietary β-mannanase and XG interacted for acetic acid (P = 0.034) and total short-chain fatty acid (SCFA, P = 0.044) concentrations in the caecal contents, where β-mannanase increased their concentrations in the absence of XG, but there were no further improvements when both enzymes were used in tandem. In conclusion, the supplementation of β-mannanase in a maize-based diet improved growth performance in the early stages of broiler development by enhancing the utilization of NSP, nutrients, and energy. On the other hand, XG improved growth performance in the grower-finisher stages; however, in this study, the combination of β-mannanase and XG did not produce synergistic effects on growth performance or nutrient and energy utilization in broilers fed maize-based diets.