The role of mannanase in feed application
As we all know, plant cell walls are mainly composed of cellulose, hemicellulose and pectin, and β - mannan and its derivatives (hereinafter referred to as mannan) are important components of hemicellulose, and it is an The main component of the cell wall is also present in high concentrations in other plant-based feed ingredients such as corn, wheat, and bran. As one of the non-starch polysaccharides, mannan has a strong anti-nutritional effect in feed. Mannanase can effectively degrade mannan, eliminate its anti-nutritional effect, improve animal production performance, improve animal immune function, etc., thereby increasing the feeding value of rations.
1. The anti-nutritional effect of mannan
The content of mannan in legumes is 1.3-1.6% . However, relevant enzymes cannot be secreted in the intestinal tract of monogastric animals. Therefore, β - mannan cannot be decomposed in the digestive tract of animals, thus causing negative effects on animal production. The main performance is as follows:
1. Mannan is a soluble starch polysaccharide, which can dissolve in water and absorb water molecules several times more than its own weight. In the digestive tract of animals, mannan dissolves in water to form a gel-like "sticky mass", and the increase in the viscosity of chyme will reduce the chance of contact between digestive enzymes in the animal and various nutrients in the feed, leading to intestinal absorption Nutrients slow down. Increased chyme viscosity can also increase the water content and viscosity of livestock and poultry manure, causing adverse effects on livestock and poultry houses and the surrounding environment.
2. Mannan is a surface-active substance with a negative charge on the surface, which can adsorb metal ions such as Ca 2+ , Zn 2+ , Na +, etc., causing metabolic blockage. It can also combine with digestive enzymes, bile salts, etc. to reduce the activity of digestive enzymes, bind the state of bile acid, and affect the absorption and digestibility of fatty substances.
3. When mannan enters the microbial flora of the hindgut, it will cause anaerobic fermentation, produce a large number of toxic bacteria and secrete toxins, which can cause gastrointestinal dysfunction and inhibit the healthy growth of animals.
2. Application of β - mannanase in feed
1. Improve the production performance of livestock and poultry
An article published by Jackson in " Poultry Science " as early as 2000 has been regarded as a classic in the field of feed enzymes. He clearly pointed out in the article that adding mannanase to the corn - soybean meal-based diet of commercial Hy-Line laying hens, As a result, the egg weight was significantly increased, and the laying time and total egg production were also improved; at the same time, after reducing the level of metabolizable energy in the diet, adding mannanase could maintain the production performance of laying hens under the condition of high-energy feed. Change. We added mannanase to the diet of growing pigs in 2010, and carried out research on animal production. Adding 500g /t to the diet , after feeding for 90 days, the results showed that mannanase can reduce the digestion of the diet 90kcal /kg , while the production indicators such as feed-to-weight ratio, feed intake and average daily gain were not significantly different from those of the conventional diet group. And the effect of adding enzymes to the low-energy diet of growing pigs is more significant than that of high-energy diets, thereby reducing feed costs and promoting the healthy growth of pigs.
2. Improve the utilization of dietary energy and reduce the cost of feed
In the turkey experiment, Jackson specifically measured the addition of β - mannanase in the corn - soybean meal-based ration , and designed that the metabolizable energy of the low-energy ration was about 60kcal/kg lower than that of the high-energy ration. β - mannanase was added to the diet, and the feed utilization rate was significantly better than that of the high-energy diet group without enzyme.
3. Promote the healthy growth of animals
The degradation product of mannan is called mannan oligosaccharide ( MOS ). As a green feed additive, mannan oligosaccharide has been widely used in the feed industry. It can significantly promote the proliferation of beneficial bacteria in the intestinal tract of animals and reduce pathogenic bacteria in the Colonization of the gut improves intestinal mucosal integrity and ultimately improves animal performance. Our research and development department found in previous experiments that adding β - mannanase to the diet tended to increase the number of beneficial bacteria (Lactobacillus) in the ileum of broilers. Mannanase can improve the health status of poultry, and mannan oligosaccharides may play a role.
4. Replace some antibiotics
The mannan oligosaccharide, the product of mannanase degradation of mannan, can directly participate in the immune regulation of animals. In addition, in the process of sharing mannanase and antibiotics, mannanase can also effectively reduce the residual rate of antibiotics in animal bodies. It has been reported that a low-energy diet supplemented with mannanase and a high-energy diet supplemented with chlortetracycline were designed respectively, and the test results in broilers showed that there was no significant difference in growth-promoting indicators between the two groups. This shows that mannanase can replace antibiotics with effective results. In the mannanase + aureomycin broiler, there was no aureomycin residue in muscle and kidney. This shows that it is also feasible to add mannanase in the diet to ensure the green and healthy meat food.
β - mannanase and its derivatives have very complex biological characteristics and action rules, and there is still a lack of a unified standard to evaluate the efficiency of the enzyme. In addition, the production process and stabilization technology of mannanase are still under further research. At present, only a scientific and positive judgment has been made on the application effect of a single mannanase in improving animal production and improving the economic value of feed. In the future, with the joint efforts of researchers in the field of feed enzymes, small enzymes will definitely play a greater role in the feed industry, and ultimately make a significant contribution to my country's breeding safety, feed safety and food safety.