Chelation of Trace Minerals

CHELATION OF TRACE MINERALS AND THEIR

BIOAVAILABILITY

GOPI.M

M.V.Sc., Scholar,

Dept. of Animal nutrition

Introduction:

Trace elements may be generally defined as those which occur or are required at relatively low concentrations in living tissues.

They have been subdivided into two categories:

those which have been established as essential for life or health, and

those for which proof of essentiality does not exist.

Macro minerals Trace Minerals Newer trace elements

Calcium (Ca) Cobalt (Co) Aluminium (Al)

Phosphorus (P) Chromium (Cr) Fluorine (F)

Potassium (K) Iodine (I) Arsenic (As)

Sodium (Na) Molybdenum (Mo) Lead (Pb)

Sulfur (S) Zinc (Zn)  

Magnesium (Mg) Copper (Cu)  

Chlorine (Cl) Iron (Fe)  

  Manganese (Mn)  

  Selenium (Se)  

Why organic minerals are important?

Inorganic mineral salts are poorly absorbed.

Absorption rates of mineral salts reported as low as 1-5%, as is with dietary copper in cattle.

More bioavailable.

Improved stability in the digestive system and less likely to encounter interferences from antagonistic minerals, fiber and phytates.

Increased awareness - potential mineral pollution so it has stimulated to reduce mineral supplementation levels in livestock nutrition without affecting animal health & production.

Use of organically complexed or chelated minerals in premixes has been a solution to this problem & have a higher bioavailability than inorganic salts.

Organic minerals may be added at a much lower concentration in the diet than inorganic minerals, without any negative affect on production performance and potentially reducing mineral excretion.

I. Mineral Interactions / Antagonists.

II. Lower Biological Activity & bioavailability.

III. Environmental Concerns

Common interactions that reduce mineral availability

• Iron: interferes with Cu, Zn, Cr.

• Cu and Zn compete for absorption sites.

• High Calcium: binds trace minerals.

• Sulfur, sulfate: reduce Cu absorption.

• Molybdenum: reduces Cu absorption

vsvsInorganic Minerals

Inorganic Minerals

Organic Trace Minerals

Organic Trace Minerals

Greater absorption due to chelation technology

No interaction or competition with other trace minerals in the body

Due to greater absorption, there is less excretion – more environmentally friendly

Small quantities needed to achieve high levels of animal performance

Absorption hindered by chemical structure

Competition between inorganic minerals leads to decreased absorption in the animal

Large amounts of inorganic minerals excreted, leads to environmental damage

Large amounts needed to achieve improved animal performance

Chelation:

Chelation, which literally means, “bringing together,” refers to a bonding formed between a metal ion (mineral) and a ligand (protein or amino acid chelating agent) carrier.

A mineral complex is a mixture consisting of a mineral and an organic compound carrier, such as a protein or polysaccharide; a chelate is a type of complex.

Chelation:

Complexing inorganic element with organic compound.

This is called ‘Chelates’.

Chelates : Chelate -Greek word - ‘Claw’

It is a cyclic compound which is formed between an organic molecule and a metallic ion. Held with in the organic molecule as if by a “claw”.

Naturally occurring chelates :

Chlorophyll's

Cytochrome

Haemoglobin

Vitamin B12

Bioavailability of minerals from chelates should also be consistent because of standardization during manufacture versus less standard conditions with some supplies of inorganic salts.

There are also claims of chelated minerals being used more effectively at the cellular level following absorption.

There are few classical supporting claims for these suppositions, and so enhanced performance of meat birds and layers is discussed in terms of stimulation of various biological processes by the mineral and/or that the chelated mineral enters certain pools with greater affinity or efficiency.

For example, the manganese in some samples of manganese sulfate has been reported at just 5%, and in this instance a 20 fold increase in inclusion level, while correcting the potential manganese absorption problem, will likely have adverse effects on utilization of phosphorus, calcium and iron.

Factors affecting the uptake of heme iron are often used to support the concept of using chelated minerals.

There are a number of other trace minerals, such as copper, manganese and phosphorus that can affect absorption of inorganic iron, while uptake of heme iron will be little affected.

The uptake of chelated minerals is therefore expected to be more consistent and less affected by adverse (or enhanced) environments in the gut lumen.

Three types of Chelates are recognized in biological system:

Group I: Chelates that serve to transport and to store metal ions.

The metal chelate is able to be absorbed, transported in the blood stream, and pass across cell membranes, where the metal ion is needed

E.g.Cysteine and Histidine, are effective metal binding agents and may be of primary importance in the transport and storage of minerals throughout the body.

E.g.: EDTA and similar synthetic ligands, are known to improve the availability of Zinc as well as other minerals. These chelates are used in medicine to hasten excretion of heavy metals, like Lead, from patients poisoned with such compounds.

Group II:

These chelates are essential in metabolism.

Haemoglobin, the cytochrome enzymes and vitamin B12 are examples. Structure of the heme portion of Haemoglobin and cytochrome –c.

Group III:

Chelates, which interfere with utilization of essential cations.

Chelates such as the Phytic acid-Zinc chelate, may interfere with normal metabolism by rendering an essential mineral unavailable for its needed metabolic function. sequestring agents- prevent insoluable compoun formation

Association of American Feed Control Officials (AAFCO, 2000)

Classification of organic minerals:

1.Metal (specific amino acid) Complex.

2.Metal Aminoacid Complex.

3.Metal Aminoacid Chelate.

4.Mineral proteinnates.

5.Mineral polysaccharide complex.

1) Metal (specific amino acid) complex:

It is the product resulting from complexing a soluble metal salt with a specific amino acid & donates two electrons to the metal to form a bond.

Minimum metal content must be declared.

When used as a commercial feed ingredient, it must be declared as a specific metal, specific amino acid complex.

e.g. copper lysine, zinc methionine etc.

2) Metal Amino Acid Complex :

It is the product resulting from complexing a soluble metal salt with an amino acid (s).

Minimum metal content must be declared.

When used as a commercial feed ingredient, it must be declared as a specific metal amino acid complex .

Metal amino acid complexes one or more undefined amino acids donate two electrons to the metal to form a bond.

Metal Amino Acid Complexes:

The structure can be destroyed in the gastrointestinal tract and the metal is released from the complex, it will behave as if it were an inorganic metal.

e.g. copper amino acid complex, zinc amino acid complex etc.;

3) Metal Amino Acid Chelate :

The reaction of a metal ion from a soluble metal salt with amino acids with a mole ratio of one mole of metal to one to three (preferably two) moles of amino acids to form coordinate covalent bonds , resulting in heterocyclic ring formations.

The average weight of the hydrolyzed amino acids must be approximately 150 and the resulting molecular weight of the chelate must not exceed 800.

The minimum metal content must be declared.

When used as a commercial feed ingredient it must be declared as a specific metal amino acid chelate .

Metal Chelates (Amino Acids and Amino Acid Analogues):

Formation of a heterocyclic ring is an absolute requirement for a chelate to exist.

It provides stability and protection during passage through the upper GI tract for optimal mineral absorption.

4) Metal Proteinate:

Metal Proteinate is the product resulting from the chelation of a soluble salt with amino acids and/or partially hydrolyzed protein.

It must be declared as an ingredient as the specific metal proteinate e.g. copper proteinate, zinc proteinate etc.;

5) Metal Polysaccharide Complex :

Complexing of a soluble salt with a polysaccharide solution as the specific metal complex.

e.g. copper polysaccharide complex, zinc polysaccharide complex etc.;

The product is generally an organic mineral matrix with chemical bonding between the metal & the polysaccharide.

How to prepare a chelate

By reaction

mineral salt + enzymatically prepared Amino acid/ peptide

Controlled condition

Ligand bind the metal atom at one or more point

Form Ring

Technology for preparation of chelated minerals

Hydrolysis of Protein

Separation by centrifuge and ultrafiltration

Chelation process

Removal of unbound mineral

Drying grinding and storage

Dinhh and Aruna Chhabra, 2003

Primary chelated mineral used in animal feeds are Primary chelated mineral used in animal feeds are

Zinc

Iron

Manganese

Cobalt

Copper

Selenium.

These are “transitional”

element

It prefer to form co-ordinate covalent bond- a hybrid form of linkage – stable complex

Properties:

Ideal chelating compound is one that will release the ionic form at the intestinal wall, or that can be absorbed as the intact chelate.

Chelate markedly enhance the absorption of a mineral by preventing to form an insoluble compound in intestine, or by preventing its adsorption on an insoluble colloid.

But some chelates hold the metal so firmly that the metal can become completely unavailable to either plants or animals (e.g: Phosphorus in Phytic acid).

However, many chelates are highly absorptive and protect the mineral from forming an insoluble complex.

This type of chelate is referred to as sequestering agent.

1. Charge / radius .

2. Neural binder – more polar – Higher tendency to coordinate metal ion.

3. Alkaline binder – Stabilization by formation of covalent bond

4. Chelation effect :

1. Mono dentate – less stable2. Multi dentate – more stable

5. Dimensions of Chelation :

1. 5 term 2. 6 term

7. Shape: Steric Tension

High stability

Factors influencing stability

Measuring Bioavailability: Biomarkers:

Biomarkers, such as changes in gene expression, or activity of a mineral-dependent enzyme.

Biomarkers are more informative when measured in S.I. Ex: Metallothionein is one such biomarker, its expression is regulated by Zn status; the magnitude of metallothionein mRNA and protein expression depends on the amount of Zn absorbed (Davis and Cousins,2000).

Metallothionein mRNA or protein expression is used as an indicator of the Zn status of animals and to evaluate the bioavailability of different Zn sources (Huang et al., 2009).

Use of chelates in Animal Nutrition

Main Objectives :

1. Reduction of antagonism, interferences and competition among minerals.

2. Improve the bioavailability of minerals

3. Counteract antinutritional factors, which affecting minerals

4. Health improvement (immune status, functional nutrition)

5. Improvement in animal produces quality (enriched meat, milk, egg, wool etc.)

6. Reduce degenerative effect of trace minerals on vitamins in premixes and feed.

7. Protect environment by reducing metal pollution.

Organic Minerals in broilers:1. Organic minerals can be included at much lower levels in the diet than the current recommendations for inorganic minerals, without any negative affect on broiler performance.

2. Feeding organic minerals replacing inorganic sources may have benefits in FCR in young broilers.

3. Using lower levels of organic minerals in broiler chicken diets results in significantly lower concentrations of minerals in manure, compared with birds inorganic minerals.

4. Excess mineral levels can utilize organic minerals in poultry diets to reduce the risk of contamination from manure without compromising animal performance.

Iron: In pigs, a major goal has been to improve the iron status

of the new-born piglet through the use of more bioavailable iron sources.

Iron chelated to amino acids has been reported to increased transfer of iron across the placenta and into the foetus (Ashmead and Graff, 1982).

When provided at 200 ppm in the gestation diet, greater quantities of Iron were incorporated into the foetuses resulting in significantly reduced mortality and heavier piglets at birth and weaning (Ashmead, 1996).

Iron absorption: occurs in upper part of S.I,

10% of food iron is absorbed.

also requires copper.

Ferrous is better absorbed than ferric form.

Fe++ forms chelates with ascobic acid, certain sugars and amino acid

AntagonistsAbsorption is impaired by presence of :Absorption is impaired by presence of : Organic acids, feeds high in inorganic iron.Organic acids, feeds high in inorganic iron.

Phytates, oxalates, gossypol.Phytates, oxalates, gossypol.

High dietry levels of Cu, Mn, Pb & Cd Decrease High dietry levels of Cu, Mn, Pb & Cd Decrease absorption.absorption.

Excess Fe, affect availability of P, Vit A, & Cu in dietExcess Fe, affect availability of P, Vit A, & Cu in diet

SynergySynergyCu, Co, Mn & Vit C are required for ironCu, Co, Mn & Vit C are required for iron

IronRelative bioavailabilty of Iron sources

Source  Poultry Swine Cattle Sheep RatsFerrous sulphate hepatahydrate 100 100 100 100 100

Ferric citrate 75 150 110 * 100

Ferric oxide 10 10 * 5 5

Ferric sulphate 85 * * * 100

Ferrous carbonate-low 5 15 10 * 5

Ferrous carbonate-high 90 95 * 85 *

Ferrous Chloride 100 * * * *

Ferrous fumarate 100 * * * *

Ferrous gluconate 100 * * * *

Ferrous sulphate, anhydrous 100 * * * *

Ferrous sulphate monohydrate 100 85 * * *

Iron - Methionine * 185 * * *

Iron - Proteinate * 125 * * *

Iron, reduced 50 45 * * 40Ammerman,1998

Copper in Ruminants:

Kincaid et al. (1986) reported a higher bioavailability from Cu proteinate compared with copper sulfate in calves fed diets containing Mo.

Diet contained higher levels of Mo, copper from proteinate was more bioavailable.

In contrast to these studies, Ward et al. (1993) found no difference in copper bioavailability between copper sulfate and copper lysine regardless of dietary Mo and sulfur levels.

Copper proteinate more bioavailable than cupric sulphate (Hemken et al, 1993).

An increased hepatic Fe content in Cu - proteinate vs cupric sulphate suggesting that Cu-proteinate did not interfere with iron uptake and storage as with inorganic Cu.

Cu-proteinate – lower plasma ceruloplasmin activity than cows fed cupric sulphate even though plasma Cu was essentially the same for both groups (Du et al., 1995).

Poultry:Cu retention was 35% higher for the birds fed

organic Cu compared to those receiving CuSO4, although in both cases, retention increased linearly with intake.

Inorganic Cu also reduced retention of Zn, whereas the organic form did not.

Relative bioavailabilty of Copper sources

Source  Poultry Swine Cattle Sheep

Cupric sulphate 100 100 100 100

Copper EDTA * * 95 120

Copper - Lysine 105 * 100 *

Copper - Methionine 90 100 * *

Copper - Proteinate * * * 130

Cupric carbonate 65 85 * *

Cupric chloride 110 * 115 115

Cupric oxide 0 30 15 *

Cuprous oxide 100 * * *

Copper:

Manganese: Birds fed organic Mn performed better

than the inorganic groups (Egorov et al., 2007).

The tissue deposition of the element has been used to estimate manganese bioavailability.

Studies have revealed that the most available sources of manganese are manganese-methionine and manganese proteinate (Henry, 1995).

Effect of manganese form and level on broiler performance (Egorov et al.,2007)

ManganeseRelative bioavailabilty of Manganese sources

Source Poultry Sheep

Manganese Sulphate 100 100

Manganese Carbonate 55 30

Manganese dioxide 30 35

Manganese-Methionine 120 125

Manganese monoxide 75 60

Manganese proteinate 110 *

Manganous chloride 100 *

Ammerman,1998

Selenium: The relative bioavailability in both blood and liver was

yeast > inorganic > chelate (Vinson, J.A).

It is surprising chelate Se an amino acid chelate fared so poorly in the bioavailability study.

Se Chelate provides high levels of selenium in the produce (meat and eggs) advantageous for the consumers.

The plasma transport form in mammals is selenocysteine (Hill et.al.1991).

SELENIUM

Form Bioavailability

Se amino acid >90%

Se methionine yeast <45%

Se methionine complex <25%

Na selenite (inorganic) <0.05%

Comparative Bioavailability Of Different Selenium Forms

Thomson 1982: Passwater 2002; Sunde 1999; Fang 1997.

Selenomethionine is the storage form of selenium in plants.

The functional, and to a certain extent storage, form in animals is selenium with one, two or all of the 3 amino acids - cysteine, glycine and glutamic acid.

Designer eggs: Seleno-eggs (Coloumbus eggs)Designer eggs: Seleno-eggs (Coloumbus eggs)

Organic Se is included @ 0.4 ppm – Increased the Se content in egg from 7.1 µg to as much as 30.7 µg (Surai et al., 2000) – provides 55-73% of the RDA from one egg

Se-milk Se-meat

Effect of zinc form and level on broiler performance (Egorov et al., 2007)

Zinc:Relative bioavailabilty of Selenium sources

Source Poultry Swine Cattle Sheep RatsZinc acetate * * * * 100

Zinc Chloride 100 100 * * *Zinc sulphate 100 * 100 100 100

Zinc carbonate 105 * 60 * *Zinc chelate * * * 110 *Zinc, element 100 130 * * *Zinc - Lysine * 100 * * *

Zinc - Methionine 125 100 * 70 *Zinc oxide 100 * 100 70 *

Zinc picolate * * * * 105Zinc proteinate 100 * * * *Zinc, sequestered * * * 105 *

Use of Organic Chromium in Heat Stress Alleviation in Poultry

High ambient temperature increases mineral excretion (Creger, 1981) and decreases concentrations of vitamin C, E, A and Fe, Zn and Cr in Serum and some tissues(Sahin et al., 2003).

Diets enriched with antioxidant substances such as vitamins C, E, A and Zn, Cr could be used to attenuate the negative effects of environmental stress (Sahin et al., 2003).

Effect of Organic Cr on immune response in Broilers: Resistance against ND and Influenza virus will be increased in broiler chicks fed supplemental Cr.

H/L ratios decreases in broiler chicks on feeding supplemental Cr.

Conc. of Ig G in serum increases by Cr supplementation.

Cr supplementation improves the immune response of heat-stressed broiler chicks.

Organic Cr apart from its effect of amelioration of heat stress in poultry it has many beneficial effects on the common metabolism that occurs body of the birds.

Chelated minerals usually cost more, per unit of metal element, than the same metal in inorganic form.

Historically the argument against chelates was that increased use of inorganics was more economic than feeding chelates.

However, there is indication that in some situations, chelates can achieve biologic endpoints that inorganics cannot.

CONCLUSION:

Chelated mineral can be used when more amount of antinutritional factor or interference affects mineral utilization.

It can be used as immuno-stimulant.

Organic minerals replacement for laying hens:Bone strength increased in all of the organic mineral groups,

(P<0.05) alongside a reduction in excretion (P<0.01 for Mn and Zn; P<0.05 for Cu and Fe).

The birds fed organic minerals showed a reduction in FCR (P<0.05).

In addition, recent studies have demonstrated that the replacement of inorganic zinc and manganese sources with zinc and manganese proteinate improved eggshell quality (Miles, 1998).

Effect of Organic Trace MineralsEffect of Organic Trace Minerals on laying performance on laying performance

Parameter Control OTM

Egg weight (g) 67.0 67.8

Dirty eggs (%) 2.7 2.5

Cracked eggs (%) 4.0 3.1Eggs/hen/day 84.5 85.5

Feed intake (g/d) 116 118

FCR 2.05 2.03

Tucker et al, 2003

Chelated, or complexed minerals are usually much more expensive than inorganic minerals, and so one expects improved bird performance through either enhanced absorption or better utilization in some way.

It is difficult to rationalize the cost of chelated minerals based solely on improved absorption in the intestine.

Even a 50% difference in absorption can be most economically resolved by doubling the level of inorganic mineral used.

However, there are limits to the level of any one mineral to be used, because of potential negative effects of absorption and utilization of other minerals and other nutrients.

Ultimately the choice of using inorganic versus chelated minerals is one of economics, which obviously relates to cost benefit.

Such results may vary depending upon the levels and spectrum of trace minerals used and the bioavailability to be expected from inorganic sources that are available.