Application of amino acid chelated iron in animal feed
As one of the trace elements necessary for animal growth and development, iron plays a particularly important role in animal health. On the one hand, as an important component of hemoglobin and myoglobin, it is mainly involved in the transport of oxygen in the body, thereby affecting the body's energy metabolism and protein metabolism; on the other hand, it is also the cytochrome and various redox reactions in the animal body. It is an important part of enzymes (such as superoxide dismutase, succinate dehydrogenase, xanthine oxidase, catalase, acetyl-CoA, etc.) and participates in many biochemical reactions in the body.
The application of iron in feed has gone through three stages of development: from the initial inorganic salt additives (such as ferrous sulfate, ferrous carbonate, ferrous chloride, etc.), to organic acid compounds (such as ferrous fumarate). Iron, ferrous citrate, etc.), and then developed to amino acid chelated iron (such as protein salt, yeast iron, amino acid iron, etc.). As a third-generation feed additive, amino acid chelated iron has the advantages of stable chemical structure, high digestion and absorption rate and high biological titer, and can be directly transported to specific target organs and enzyme systems once absorbed, thus greatly improving utilization rate. Relevant statistical analysis results show that the use of amino acid chelated iron can indeed increase the growth rate of animals, greatly improve the immunity, and reduce the unnecessary loss of such additives. It can be seen that the application of amino acid chelated iron in animal feed is of great significance for further promoting the development and research of feed nutrition.
1 Basic concept of
amino acid chelated iron Amino acid chelated iron is formed by covalent bonding between iron ions in soluble iron salts and amino acids in a certain molar ratio, mainly by one or more groups and an iron ion. The ring structure formed by coordination, this structure makes the charge in the molecule tend to be neutral, and its stability constant is moderate, which is more conducive to the release of iron in the digestive tract.
2 Characteristics of
amino acid chelated iron 2.1 Chemical structure stability of amino acid chelated iron
The stability of amino acid chelated iron is mainly determined by its stability constant. The stability constant refers to the affinity of the chelating agent for iron ions in the chelate. If the stability constant is too low, the iron element is easily dissociated into iron ions in the gastrointestinal tract environment of the body; on the contrary, if the stability constant is too high, when the body needs iron ions, because it is too stable, the chelate cannot The iron ions needed by the body are released in time, which makes the body digest and absorb iron ions well but cannot make better use of the iron ions coordinated therein. However, if the stability constant of forming amino acid chelated iron is more suitable [2], its molecular structure is symmetrical and balanced, and the charge in the molecule tends to be neutral. Phosphoric acid, calcium ions, etc.) have a high chemical structure stability, which can promote the body's better absorption of iron ions, and on the other hand, can quickly and efficiently release iron ions from the body when needed. The ligands are released, so that their utilization efficiency is greatly improved.
2.2 Amino acid chelated iron has efficient body utilization and biological potency
Compared with inorganic iron ions, amino acid chelated iron has more efficient utilization efficiency, because amino acid chelated iron is mainly transported through the placenta. The blood is digested and absorbed, while inorganic iron ions cannot pass through this special pathway. Studies have found that the utilization efficiency of amino acid chelated iron is significantly higher than that of inorganic iron (such as ferrous sulfate), especially peptides with reduced nitrogen-terminal cysteine can efficiently promote the digestion and absorption of iron ions. And amino acid chelated iron can further promote the body's digestion and absorption of iron ions by buffering the pH value in the gastrointestinal tract. When sodium bicarbonate is used as the buffer system, the buffering capacity of amino acid chelated iron is 3 times higher than that of ferrous sulfate [ 3]. The content of iron in plasma is an indicator for judging whether the body is iron deficient. Compared with inorganic iron, the detection value of this indicator of amino acid chelated iron is significantly increased, which once again proves that the utilization efficiency of amino acid chelated iron is much higher than that of inorganic iron. Inorganic iron. Studies have shown that when the relative biological titer of ferrous sulfate is 100%, the relative biological availability of amino acid chelated iron is 125% to 185%, such as the relative biological availability of iron methionine to 7-28-day-old piglets. The academic titer was 120.0%, the relative biological titer of iron glycinate was 118.5%, and the relative biological titer of iron lysine was 124.3%.
2.3 Amino acid chelated iron has less toxicity and better safety Inorganic iron salts will not only affect the pH value in the gastrointestinal tract and the body's acid-base balance, but also have a serious impact on vitamins necessary for the body by oxidizing vitamins. The amino acid chelated iron can not only provide amino acids and iron ions necessary for the growth and development of the body, but also avoid the damage to the body nutrients such as vitamins and fats, with less toxicity and better safety. Because the efficiency of inorganic iron salts being digested and absorbed by the body is extremely low, and most of them are excreted through feces, it is easy to cause a certain degree of damage to the soil environment, causing the enrichment of iron in the soil and crops, resulting in its content exceeding the national soil environmental quality. standards, thereby further causing a greater negative impact. However, due to the efficient digestion, absorption and utilization efficiency of amino acid chelated iron, it can also reduce its toxicity to soil.
2.4 Amino acid chelated iron has high absorption efficiency.
In amino acid chelated iron, iron ions and amino acid ligands form a stable ring structure. Because it is closer to the natural form inherent in enzymes, it is more beneficial for the body to absorb iron. The digestion and absorption of ions, on the one hand, reduces the effect of iron ions and other substances (such as phytic acid, phosphoric acid, calcium ions, etc.) Once absorbed, it can be directly transported to specific target organs and enzyme systems, thus greatly improving its absorption efficiency. Studies have shown that the absorption efficiency of amino acid chelated iron is 3.6 times higher than that of carbonate and 3.8 times higher than that of sulfate.
3 Application of amino acid chelated iron in animal feed
3.1 Amino acid chelated iron can improve the immunity of the body
Studies have shown that oral amino acid chelated iron can significantly increase the hemoglobin content of piglets and the iron content in plasma. Therefore, it can not only prevent piglet anemia, but also improve the body's immune disease resistance. The addition of amino acid chelated iron to the diet of sows can reduce the rate of postpartum uterine infection, accelerate the recovery of uterine tissue and reduce embryonic and fetal mortality, thereby improving the reproductive performance of sows. In particular, the addition of amino acid chelated iron to the feed of pregnant sows and piglets on the 20th postpartum can significantly enhance the disease resistance of piglets, promote their healthy growth and development, and can increase the body weight of piglets by 11.24% to 18.76% and cause death. rate decreased by 30.4%.
3.2 Amino acid chelated iron can prevent anemia
Iron deficiency will not only cause anemia in piglets, but also reduce their immune resistance to the outside world, making them vulnerable to the invasion of Escherichia coli and other pathogenic bacteria, thereby causing diarrhea and gastrointestinal inflammation and other diseases. Piglets only obtain antibodies from colostrum and cannot meet their growth needs, and they also have the ability to synthesize antibodies, and iron is an important part of the enzymes required to synthesize antibodies. Therefore, it is the key for piglets to absorb enough iron to improve their autoimmune disease resistance. However, if inorganic iron is used as an additive, it is easy to cause excessive iron in a short period of time, resulting in excessive iron saturation, which is not conducive to the growth and development of piglets, and amino acid chelated iron is used in sows about 28 days before giving birth. , then the iron element can be transmitted to the fetus through the placenta, so that the postpartum piglets can synthesize the antibodies needed for growth through the iron element transmitted by the mother without supplementing iron, which makes their own Immunity is greatly improved. Studies have shown that the use of amino acid chelated iron in sows 2 weeks before and 3 weeks after birth can effectively prevent anemia even if piglets are not supplemented with iron after birth [4].
4. Problems existing in the production and application of amino acid chelated iron
Whether from economic benefit or environmental protection, the application of amino acid chelated iron in animal feed has broad development prospects and development potential. Although amino acid chelated iron has many advantages in feed nutrition, from the current point of view, there are still many unknown fields in the research of amino acid chelated iron, mainly including the following aspects.
①Among the amino acid chelated irons sold in the market, the price of imported products is relatively high, which makes it difficult to be effectively used and promoted in actual production. Moreover, domestically, there has not been successfully developed and researched products that can obtain low-cost and high-yield products. Process flow of amino acid chelated iron. Therefore, as far as the current situation is concerned, it is still necessary to invest a lot of manpower and material resources to scientifically and reasonably optimize its production and processing processes, and rationally design the product formula of amino acid chelated iron. Only in this way can production costs be further reduced and products improved. quality.
②The product quality detection technology of amino acid chelated iron still needs to be further explored. The currently used detection methods such as spectrophotometry and potentiometric method cannot satisfy the quantitative analysis of the chelation degree, so it is difficult to accurately detect the quality of the product. Only by developing a set of low-cost quantitative and qualitative detection new technologies that can accurately evaluate the relevant indicators of amino acid chelated iron, can the market demand be better met.
③ Although compared with inorganic iron agents, the amino acid chelated iron has higher digestion, absorption and utilization efficiency, but its absorption efficiency, utilization efficiency, relative biological titer and other aspects still have a large room for improvement. The difference in the structure and processing technology of amino acid chelated iron will lead to changes in its stability. Therefore, to explore the best structural form of amino acid chelated iron in animals, which amino acid, polypeptide and iron form the most effective chelate. It is still the main direction of research in many aspects, such as how the optimal chelation degree of amino acid chelated iron affects its utilization of iron.
④In practical applications, the determination and optimization of the optimal addition time and optimal addition amount of various amino acid chelated iron still need to be further explored.
