Corn gluten meal is the main by-product of wet milling of corn and contains at least 60% protein. Corn gluten meal is a high-energy and high-protein feed resource and a low-cost protein feed resource in animal production applications. Corn gluten meal is rich in various amino acids, such as methionine, cystine and leucine. In addition, the carotene and lutein in corn gluten meal can promote lipid metabolism in broilers. As a high-protein feed ingredient, corn gluten meal is increasingly used in animal production, especially in poultry production. However, corn gluten meal has the characteristics of high proportion of insoluble protein, high content of anti-nutritional factors, amino acid imbalance and lack of essential amino acids, etc., resulting in poor feed utilization effect of corn gluten meal, and it is difficult for poultry to be absorbed and utilized by microorganisms in the intestines after eating. Food is excreted from the body, causing waste. In order to improve the utilization rate of corn gluten meal in poultry farming, appropriate pretreatment is necessary. Microbial fermentation pretreatment can not only change the protein structure of corn gluten meal, but also improve the amino acid balance and improve the absorption and utilization rate of animals. In addition, fermented corn gluten meal is rich in probiotics and has a positive impact on the balance of the poultry intestinal microbial environment.

Nutritional values and mechanism of action of corn gluten meal.

Corn gluten meal has high nutritional value, with protein of 61%~71%, carbohydrates 21%~26%, starch 12%~15%, fat 3%~7%, cellulose 1%~2%, and amino acid content. Corn gluten meal has low water solubility and lacks certain essential amino acids, such as lysine and tryptophan, which greatly limits its application in animal feed. Enzymatic hydrolyzate contains many small peptides, especially dipeptides and tripeptides, and small peptides are more easily absorbed by the body than intact proteins or free amino acids, so enzymatic hydrolysis can significantly improve the bioavailability of corn gluten meal. In addition, the amino acid residues produced by partial enzymatic hydrolysis of the whole protein are beneficial to protein synthesis in livestock and poultry. Corn gluten meal protein is a good source of bioactive peptides because it has a special amino acid composition and is rich in hydrophobic amino acids such as leucine, alanine and phenylalanine. Studies have reported that adding corn gluten meal to broiler diets can promote lipid metabolism and improve immunity of broilers. In recent years, the use of microbial fermentation of corn gluten meal to prepare corn peptides has become the focus of many researchers. Fermentation and hydrolysis of corn gluten meal to produce corn peptides has important application value. The chemical composition and physical and chemical properties of corn peptides are different from corn gluten meal, and the properties of the protein can be improved by controlling hydrolysis. Corn peptides have higher water solubility and many desirable physical and chemical properties than corn gluten meal. The structural characteristics of corn peptides are the main reason for its increased solubility, which is mainly manifested in high solubility within a certain pH range, forming a solution without precipitation or floating phenomenon. After corn gluten meal is fermented by microorganisms, the protein structure is changed, the surface area is increased, and the hydrophilicity of amino acids is also increased. Part of the protein is hydrolyzed by proteases into active peptides, small peptides and free amino acids. The free amino acids can improve the palatability of feed, thereby increasing the nutritional value of corn gluten meal. In addition, after fermentation, corn gluten meal changes the α-helical structure of the protein molecules and is hydrolyzed into macromolecular proteins, which can improve the digestion and utilization rate of corn gluten meal in animals.

Effects of corn gluten meal on poultry growth.

Fermented corn gluten meal has a positive impact on poultry performance. Fermented corn gluten meal using complex bacterial preparations can significantly improve the feed intake and daily weight gain of broilers, and has a positive impact on the growth and development of broilers. Adding microbial fermented corn gluten meal to the diet of laying hens can reduce the feed-to-weight ratio and mortality of laying hens. There are reports that fermented corn gluten meal feed can effectively regulate the intestinal microbial environment of livestock and poultry and improve feed conversion efficiency. Fermented corn gluten meal has a positive impact on poultry growth performance.

Corn gluten meal has a positive impact on poultry immune function. Fermented feed contains a variety of probiotics. After being eaten by animals, more albumin and total protein are produced in the body through blood circulation, which enhances the body's immune function, stimulates the body's immune response, activates the immune system, and kills invading pathogens.