β-mannanase (β-1, 4-D-mannanase, EC 3.2.1.78) is a kind of hemicellulose hydrolase which can degrade β-1, 4-glycosidic bond by endo and the non-reducing terminal of the degradation product is mannan-oligosaccharide, the action substrates being the β-mannan, galactomannan and gluco-mannan.

β-mannanase can degrade β-mannan, decrease digesta viscosity and destroy the structure cell wall of the botanical feed. Mannan-oligosaccharide, being the degradation product, it can improve the microorganism flora in the intestine and improve the intestinal mucosa integrity.

1. β-mannanase can degrade β-mannan, eliminate anti-nutrition effect of β-mannan, increase the feed digestibility and, improve the secretion of insulin and the production of insulin-like growth factor IGF-1 to improve carbohydrate metabolism for better energy utilization. Meanwhile, IGF-1 is the real growth regulatory factor of livestock and poultry and it mediates the growth effect of the growth hormone (GH). Acting on the growth organization and stimulating the amino acid utilization of the cells, it helps the protein synthesis, eliminates the decomposition of protein and helps the protein net growth of animals.

2. β-mannanase can also degrade mannan into mannan-oligosaccharide, which is beneficial for intestinal microorganism population and for the host, moreover, the mannan-oligosaccharide can distinguish, bond to the pathogenic microorganism and then eliminate them, it can regulate body immune thus improve the performance of the livestock and poultry. Mannan-oligosaccharide can competitively combines with certain pathogenic bacteria in the animal bodies and improve the proliferation of beneficial bacteria, by these, reduce the contact between the pathogenic bacteria and epithelial cells of the intestinal mucosa, greatly reduce the incidence rate and help the animal bodies grow healthy, thus achieve the goal of disease prophylaxis, resistance and finally cure. In the mean time, researches show that mannan-oligosaccharide, produced by degradation, can eliminate the harmful effect of mycotoxin on livestock and poultry by physical adsorption or direct integration.