ß-Mannan and mannanase in poultry nutrition

Dietary plant ß-mannans are one of the major anti-nutritional components in monogastric nutrition. The presence of ß-mannans in poultry diets has been associated with many negative features ranging from high intestinal viscosity and low nutrient digestibility to adverse effects on innate immune response and microbial proliferation in the gut. ß-Mannanase supplementation to the feed of domestic fowl is one of the strategies for optimisation of nutritional value of ß-mannan containing diets. Research has shown positive effects of ß-mannanase supplementation on performance and nutrient digestibility in poultry fed corn-soybean meal-based diets as well as diets containing guar meal, copra meal, and palm kernel meal. Such performance and nutrient digestibility improvements are the result of single or combined modes of action due to ß-mannanase addition. Particularly over the last decade, it has become increasingly clear that these modes of action might be very complex and versatile. The identification and understanding of the mechanisms by which ß-mannanase supplementation affects nutrient digestion, metabolism, overall performance and health of birds, is important for the optimisation and broadening of the application of this enzyme in avian nutrition. This paper reviews various modes of action by ß-mannanase supplementation in poultry. Additionally, significance of single modes of action under different conditions is also discussed.