Detailed Introduction:

Trace element amino acid chelate is a new type of feed additive, which is composed of amino acids or short peptides chelated with trace elements by chemical methods. Trace element amino acid chelates can improve the absorption and utilization of metal ions in the body, prevent trace elements from forming insoluble substances, have certain sterilization and improve the immune function of the body, and play an important role in improving the production performance and anti stress ability of livestock and poultry. They are a new and efficient green feed additive.

Properties and types of amino acid trace element chelates

Amino acid trace element chelate is formed by covalent bond between a metal ion in a soluble metal salt and amino acid according to a certain molar ratio. The average molecular weight of hydrolyzed amino acid is close to 150D, and the molecular weight of chelate should not exceed 800D. Amino acid trace element chelates have one or more chelating ring structures, and the intramolecular charge tends to be neutral. They have good chemical and biochemical stability. Metal ions are not easy to dissociate in the gastrointestinal tract and are little affected by phytic acid, calcium, fiber and phosphoric acid in the feed. The determination of absorption radioisotopes in gastrointestinal tract showed that the degree of absorption and metabolism of amino acid chelates was better than that of other general inorganic salts and trace elements.

A central ion can form a polycyclic chelate with multiple amino acids. The more rings formed, the better the stability of the chelate. The common stable chelate ring structures are five membered ring and six membered ring（ α- The amino acid chelate is a five membered ring, β- Amino acid chelate is a six membered ring). Trace element amino acid chelate is formed by covalent bonding of a metal element ion in a soluble metal salt (such as Fe2 +, Cu2 +, Zn2 +, Mn2 + and Cr3 +) with amino acid in a certain molar ratio. The average molecular weight of hydrolyzed amino acid must be about 150D, and the molecular weight of chelate shall not exceed 800D.

Nutritional function of amino acid trace element chelates

2.1 promote the absorption of metal ions with high biological potency

After the trace elements formed by inorganic salts and simple organic salts are ingested by animals, metal ions need to be in the form of chelates between carrier molecules and elements before they can be absorbed by the body through the cell membrane. The charge in the chelating molecule tends to be neutral and has good solubility in the gastrointestinal tract. It can quickly transport trace elements to the intestine, which is conducive to the absorption of small intestinal mucosa. Fouynd (1974) believed that metal elements located in the center of chelates with five or six membered rings can directly pass through the brush edge of small intestinal villi, and all chelates may be absorbed in the form of amino acids or peptides.

Amino acid chelates are not only the main form for animals to absorb metal ions, but also the intermediate material in the process of protein synthesis in animals. Therefore, amino acid chelates not only promote the absorption of metal ions, but also reduce many biochemical processes, save energy consumption and have high biological potency. Henry (1989, 1992) reported that the bioavailability of chelated iron and protein iron was 125% ~ 185%. The study on chicks showed that the utilization of manganese in manganese methionine was 108% and 132% of manganese in manganese sulfate, respectively. The results showed that the biological utilization rate of manganese methionine was 120% of manganese sulfate, and compared with manganese sulfate, manganese methionine improved the feed utilization rate.

2.2 form a buffer system to reduce the damage to vitamins

The reaction between metal ions and organic ligands provides a buffer system for the concentration of metal ions in the medium. The buffer system keeps the concentration of metal ions constant by dissociating chelates. Inorganic salts will affect the pH value in the gastrointestinal tract and the acid-base balance in the body. Amino acid chelates are normal intermediates in the body and rarely have adverse stimulating effects on the body, which is conducive to animal feeding and gastrointestinal digestion and absorption. At the same time, it can strengthen the enzyme activity in animals and improve the utilization of protein, fat and vitamins. Experiments show that most vitamins are very sensitive to the catalysis of Fe2 + and Cu2 + oxides. For example, vitamin C can decompose 1000 times faster when there are 0.0002mol/l catalytic metal ions. Therefore, adding Fe2 + and Cu2 + in the form of chelates can effectively prevent the destruction of vitamins.

2.3 improve immune function and enhance disease resistance

After being absorbed into animals, chelated trace elements can be directly transported to specific target tissues and enzyme systems to meet the needs of the body. It is reported that amino acid chelates may play a role in animals as a "separate unit", such as improving animal fur conditions and reducing early embryo death. Amino acid chelates can kill bacteria and improve the immune function of the body. They have a significant therapeutic effect on some enteritis, skin diseases, anemia and dysentery.

Nockels (1991) reported that zinc methionine can improve the immunity of chickens, weaned piglets and sheep compared with the same amount of zinc oxide.

Kienholz (1992) proved that adding zinc methionine can prevent the decline of egg production in the period of low calcium stress and recovery. Zinc methionine supplementation during low calcium stress has higher egg production rate and * * * * egg weight than the control group. The results showed that zinc methionine could increase the primary antibody titer of broiler breeders and broilers against Salmonella pullorum antigen and increase the cellular immune level of offspring. Zinc methionine improves the survival rate, cell integrity and phagocytic activity of monocyte macrophages.

Ashmead (1996) added 200mg / kg to the pregnancy diet, which can greatly increase the iron passing through the placenta and entering the fetus, greatly reduce the mortality of newborn piglets, and significantly increase the birth weight and weaning weight of piglets.

2.4 high safety and good palatability

As the intermediate product of biochemical process in the body, trace element chelates have little side effects on the body, and their half lethal dose is much greater than that of inorganic salts. General inorganic salts have poor palatability, and trace element amino acid chelates overcome this defect. It contains a large number of amino acids, has good palatability, has food inducing effect, and is easy to be eaten and absorbed by animals.

2.5 improve the anti stress ability of the body

Amino acid chelates have good effects under stress conditions such as inoculation, castration, high temperature and changing diet. Zhang Shidong et al. (1998) showed that adding zinc methionine to feed can reduce the heat stress response of laying hens and improve the quality of eggshell under high temperature environment. The results showed that zinc methionine promoted the recovery of growth performance of castrated bulls after stress during transportation and inoculation, while zinc methionine supplementation significantly decreased the egg breaking rate of laying hens.

2.6 it has specific advantages and can reduce the use of antibiotics

Trace element ions are sealed in the chelate ring, which is relatively stable and greatly reduces the oxidative (catalytic) damage to vitamins added in feed; Chelates protect trace elements from being taken away by acids; It avoids the interaction of a large number of antagonistic metal ions in the digestive tract, and the trace element amino acid chelate has a dipeptide like structure, which also reduces the competition of amino acid absorption and transport; For ruminants such as cattle and sheep, the chelate can resist the degradation of amino acids by microorganisms and protect the passage of restrictive essential amino acids through rumen because the amino coordination atoms are locked by coordination bonds; For specific diets (high phytic acid in bran), specific animals (suckling pigs and ruminants), specific stages (before and after delivery) and specific environment (stress), the effect of selecting corresponding chelates is very obvious. On the one hand, amino acid chelates can meet the needs of animals for trace elements, on the other hand, they can enhance the ability of animals to resist diseases and reduce the application of antibiotics to a certain extent. Due to the small amount of metal elements, it can also reduce the pollution to the environment.

Published date：01-04-2021  Viewed：450