Study and Application of Amino Acid Chelated Trace Minerals
(As Feed Additives)
Trace minerals have been widely applied as feed additives and since last century, there were three stages of its application. Firstly, inorganic minerals, especially in sulfate form and oxide form, had been widely used but too many disadvantages were found when application. For example, inorganic minerals caused antagonism to other nutritional matters, broke nutrition like vitamins, offering lower bioavailability, affected the uniformity when mixing the feedstuff, etc. Based on these disadvantages, the second generation of trace minerals, organic acid salt, was released. But it still had many same disadvantages as inorganic salt had, for example, low bioavailability, unstable biochemical effects, etc. In 1970s, the third generation of trace minerals, chelated trace minerals, was promoted in USA and it was proved to be a new type feed additive with high efficiencies including good stability, easy to be absorbed, excellent bioavailability, etc. The researches of chelated trace minerals started in China since 1980s and have got good feedback with animal experiment and intensive production on swine, ruminants, poultry, rabbit and aquatic animals. Currently the major product of chelated minerals including glycine chelate and Methionine chelate, and also many compound amino acid chelated minerals.
1. Chelated Trace Minerals and its characteristics
The definition of chelated trace minerals was given by Association of American Feed Control Officials (AAFCO) in 1996. According to AAFCO, a metal amino acid chelate is defined as the product resulting from the reaction of a metal ion from a soluble metal salt with a mole ratio of one to three (preferably two) moles of amino acids. The average weight of the hydrolyzed amino acids must be approximately 150 and the resulting molecular weight of the chelate must not exceed 800 Da.
1.2 Structure of Amino Acid Chelated Minerals
The chelation is ring compound resulted from coordination reaction by one or more group(s) with a metal ion. One metal ion can be bonded with several amino acid groups. More rings existing in the compound will cause much stable structure. Usually there are five-membered ring (e.g. amino acid chelation) and six-membered ring (e.g. a-amino acid chelation). Because the different coordinating ratio of metal ion, the chelating ratio of metal ion and amino acid could be from 1:1 to 1:3 by mol. Several factors could affect this ratio, including reaction temperature, reaction time, pH value of the reaction solution and the feeding percentage of raw materials, etc. Amino Acid chelated minerals include a single chelation which is from single metal and single amino acid, but also include compound chelation which is from several metal and compound amino acids.
2. Reaction Mechanisms of Amino Acid Chelated Minerals inside animal
2.1 Prevent the developing of insoluble matters
Fhytic acid, oxalic acid or phosphoric aicd contained in the plant feed is very apt to bond the free metal ions to form insoluble salt which is not able to absorbed by the animal digest system. Tetracycline or its derivates contained in the feed is also apt to bond the free metal ions too. And both will strongly affect the absorption of trace minerals by the animal body. But the amino acid chelated minerals offers a much better chemical stability because of its special structure. The metal ion has been well protected with this structure thus it offers much better absorption ratio.
2.2 Decrease Antagonistic Action & others
There are complicated and apparent antagonistic action between trace minerals, i.e. between Fe and Zn, between Cu and Mo., etc., In the meantime, stone powder is widely used in feed as carrier or thinner which obviously increased the content of Ca2+. But Ca2+ will have antagonistic action with many trace minerals. Besides, inorganic metal ion is easily to be oxidized or reduced when manufacturing, transporting or storing the feed, for example, Fe2+ could be oxidized to be Fe3+, Cu2+ could be reduced to be Cu+. These reaction and the reacted products will break the vitamins and loss minerals in the feed, CO32- in the additives and the alkaline conditions caused by choline accelerated the above said reactions.
Because of the chemical stability and good protection of metal ions, amino acid chelated minerals will inhibit the antagonistic action between metal ions, and decrease the breaking to the vitamins in feed. This will help to protect the loss of nutritional matters and increase the absorption.
On the other hand, inorganic minerals will affect the pH value in animal gastrointestinal but chelated minerals will offer buffer function to decrease the stimulation to the animal body.
2.3 Increase the absorption ratio because of the unique absorption path
The inorganic metal ion will be absorbed by body after passing the cell membrane. The ion has to be wrapped by some available carrier molecular to form some organic fat-soluble compound outside the cell membrane before it could be able to delivered through the membrane. According to Found, the metal ion which is located in the center of five-membered ring or six-membered ring could pass the small intestine villi, and the whole chelate organ could be absorbed as the form or amino acid or peptide. Vandergrift also raised that, once the metal is chelated with amino acid or peptide, the absorption of metal will be completely resulted by the amino acid or peptide. There is no strict requirement for a animal body to absorb amino acid chelated minerals. All chelates whose molecular weight is below 1000u could be easily absorbed with cell membrane, and at some special physiological period (for example, newborn animals), chelate with molecular weight higher up to a hundred thousand could be directly absorbed with the method pinocytosis. These unique absorption paths of amino acid chelated minerals could largely increase the bioavailability.
2.4 Increase the utilization ratio of metals due to unique metabolism
After absorption, according to the requirement of different single amino acid in different organism or enzyme system, the metal which is chelated with different single amino acid will be directly delivered to specific organism or enzyme system respectively. This will save the biochemical process as needed for absorbing inorganic minerals and will save the metal utilization ratio.
According to some experimental results, amino acid chelated minerals will offer some special benefits including improve the status of animal fur, decrease the early embryonic death ratio and increase the enzyme activities, etc.
2.5 Offer Double Nutrition Facts and Anti-Stress Function
When absorbing amino acid chelated minerals, the animal have gained two necessary but probably lack nutrition facts in the feed, that is, trace minerals and amino acid. Amino Acid chelated minerals have very good performance on anti-stress of animals. It also offers many other benefits including: improving the antimicrobial ability, improving the immunity, increasing the enzyme activity, etc.
2.6 Improve the Feed Palatability, Decrease the Metal Side Effects
Amino Acid chelated minerals will not bring special taste or smell to the feed as inorganic minerals do. This will improve the feed palatability to some extent.
The overtaking of inorganic minerals will cause the poisoning to the animals, and may cause insoluble salt precipitation with other growth-promotion additives. Amino Acid chelated minerals could offer much lower side effects because of its unique structures.
3. Application Effect of Amino Acid Chelated Minerals in animal production
It could improve the sow physique, improve the reproduction performance and decrease the piglet mortality if Methionine chelated Iron is added into the feed for Sow. By doing so, it also improve the piglet health condition and effectively prevent the piglet anemia.
According to statistics, by adding Methionine chelated iron in the late gestating of sow, the piglet mortality rate decreased by 3.2%, the number of starters increased by 4.4%. It also decrease the culling rate of sow.
Feeding Methionine iron to primiparous sow and sow, compared to feeding ferrous sulfate, the first breeding conceive rate of primiparous sow increased by 7.2%, number of stillborn decreased by 2.1%, post-weaning mortality decreased by 2.9%, weaning to breeding interval shorten by 1.35 days; stillborn rate by the 2nd to 8th farrowing sow decreased by 7.1%~29.6%, post-weaning mortality decreased by 3.1%~6.2%.
Other experiments show that, feeding glycine chelated iron to sow, the content of iron in colostrum is substantially more than that fed by ferrous sulfate, and the piglet could maintain the hemoglobin at normal level without adding extra iron.
By feeding amino acid chelated minerals to piglets, there already have actual effects in preventing piglet nutritional anemia, improving the piglet daily body gain, improve the piglet immunity and anti-disease ability, etc. Spears fed Methionine chelated iron to 3 days pre-starters, comparing to feeding ferrous sulfate, the mortality decreased by 30.4%; feeding Methionine chelated iron to piglet diet, the rate of infecting with dysentery decreased by 4.3%. Mr. Feng Zhanyi add methionine chelated iron to diet for gestating sow in the last month of gestating and 20 days after farrowing by 60mg/kg and to supplement for piglet by 11mg/kg, and found the piglet body weight when weaning increased by 11.2%~18.6%, and the daily body gain increased by 17.64%~29.4%. According to reports from Ward, adding 250mg/kg methionine chelated zinc will increase the body weight by 8% and feed efficiency by 10%, comparing to adding 161mg/kg zinc sulfate.
3.1.3 Growing Swine
Adding certain percentage of amino acid chelated minerals into the diet of growing swine could be helpful to the growth of swine, and could also substantially increase the daily body gain, increase the feed conversation rate and improve the meat quality.
According to statistics, amino acid chelated iron could help to increase the daily body gain by 9.56% and increase the feed conversation rate by 7.09, and the hemoglobin increased by 2.39g/11ml.
Adding amino acid chelated minerals into broiler feed could help to improve the growth of broiler, decrease the feed consuming and increase the feed conversation rate.
According to statistics, Methionine chelated manganese, compared to inorganic metal plus Methionine, could increase the daily body gain by 2%~7%, increase feed conversation rate by 2%, increase protein digestibility by 4.6%; adding amino acid chelated copper, amino acid chelated iron into feed for 49 days broiler , the daily body gain increased by 5.28%, and the feed conversation rate increased by 2.59%.
Adding amino acid chelated minerals into layer feed could help to increase the egg laying rate and feed conversation rate, and could also improve the layer immunity and decrease the layer skin tear and egg breakage.
According to report, feeding compound amino acid chelated minerals to feed for Dekalb Layers of 35 weeks, the laying rate increased by 12.8%, the egg weight increased by 21%, and the eggshell thickness and eggshell strength increased much a lot.
According to statistics, feeding methionine chelated manganese to growing beef cow, daily body gain increased by 0.67kg, feed conversation rate increased by 11.2%; feeding Methionine chelated zinc to calf, body weight when weaning increased by 5%; feeding Methionine chelated zinc to cow, the conception rate increased by 15%. According to Kellogy, feeding Methionine chelated zinc to dairy cow at 360mg per day, the milk production increased by 5%. John Herrick reported that Methionine chelated zinc is strongly anti-decomposition in rumen, and it helps to prevent decomposition of amino acids caused by microorganisms, and decrease the inorganic zinc poisoning to the rumen.
Feeding Methionine chelated zinc to sheep, the result shows that, the nitrogen deposition rate (36.20%) is substantially higher than the blank group (24.31%) and zinc oxide fed result (25.39%), the apparent digestibility of Methionine chelated zinc group is higher than zinc oxide group by 6.8%, and deposition rate higher by 7.77%. Tracing the dynamic zinc excretion status with isotope (65Zn) labeling technology, it is appeared that the zinc content in faeces of Methionine chelated zinc group is obviously that in inorganic zinc group, and in urine, the zinc content in Methionine chelated zinc group is obviously lower than the inorganic zinc group, and the apparent absorption rate of diet of Methionine chelated zinc is substantially higher than the inorganic zinc group.
3.4 Aquatic Culture
Feeding amino acid chelated minerals to fish, it could be helpful to improve the health condition and the growth of fishes, and it also able to increase the feed conversation rate and the fish survival rate.
According to experiments on carp, comparing to blank group, the three amino acid chelated minerals group have significant effects, weight increased by 37.2%~68.1%, feed coefficient decreased from 2.4 to 1.4~1.7. Adding Methionine chelated minerals (Cu 2mg, Zn 30mg, Mn 12mg, Fe 150mg, Co 2mg, Mg 400mg) to every 1kg feed, the growth rate of tilapia increased by 17.84%~25.84%. Adding Methionine chelated minerals to carp, the digestive rate of minerals increased respectively, Cu & Co 41%~58%, Fe & Zn 14%~16%, Mn 5%~7%.
According to experiment, both Methionine chelated copper and copper sulfate could be helpful to the growth of prawn, but the utilization rate of Methionine chelated copper is much higher than that of copper sulfate. It is only 15mg/kg of Methionine chelated copper is required to meet the requirement of prawn growth, but for copper sulfate, the required amount is 30mg/kg.