Significance of single β-mannanase supplementation on performance and energy utilization in broiler chickens, laying hens, turkeys, sows, and nursery-finish pigs: a meta-analysis and systematic review

Abstract

This review will give a brief description of β-mannans, abundance in feedstuffs, utility of supplemental feed β-mannanase and subsequent animal responses. Soybean products and co-products of processing palm, coconut and guar seeds are the major sources of β-mannans in poultry and livestock feed. β-mannans are linear polymers of mannose residues linked by β-1,4 glycosidic bonds and their ingestion elicit undesirable and metabolically costly responses. Web of Science was searched to retrieve published studies for meta-analyses of the impact of supplemental β-mannanase on performance and digestibility in pigs and poultry. The mean difference (MD) between ß-mannanase and control on average daily gain (ADG, g/d) was +0.23 (P=0.013; 95% CI 0.05; 0.41), +10.8 g/d (P=0.0005; 95% CI of 6.6; 15.0 g/day) and +20.68 (P<0.000; 95% CI of 17.15; 24.20 g/day) for broiler chickens, nursery pigs and grow-finish pigs, respectively. The MD on β-mannanase improvement on FCR was -0.02 (P<0.0001) with 95% CI (-0.03; -0.02) suggesting a 2-to-3-point FCR improvement in broiler chickens. ß-mannanase improvement on gain to feed (G:F) was +13.8 g/kg (P=0.027; 2.1; 25.4 g/kg) and +8.77 g/kg (6.32; 11.23 g/kg) in nursery and grow-finish pigs, respectively. β-mannanase improved AMEn by 47 kcal/kg (P=0.0004) with 95% CI (28.8; 65.7 kcal/kg) in broiler chickens. The improvement of gross energy digestibility in pigs was 1.08 percentage unit with 95% CI (0.90; 1.26) translating to the release of between 30.6 and 42.8 kcal/kg of digestible energy. Although data was limited, β-mannanase improved egg production but had no impact on egg quality in laying hens. Turkeys may be more adversely affected by ß-mannans because of the high protein/ amino acids requirements necessitating higher dietary inclusion of soybean meal. However, growth performance and feed efficiency responses of turkeys fed diets supplemented with β-mannanase was variable. In summary, ß-mannanase supplementation improved performance linked to energy and nutrient utilization. However, the magnitude of response was variable within and between species indicating further application refinement is warranted to achieve consistent efficacy, including an improved understanding of the functional contribution of β-mannans hydrolysis products.