Unlocking the Secrets of Bioavailability and Utilization of Minerals in Farm Animals

Impact of Trace Mineral Status on Biological Function:

The nutritional status of animals is an indicator of their productivity and reproductive capabilities. In tropical countries like India, mineral imbalances or deficiencies are prevalent. (Mc Dowell et al., 1993) . Livestock in India typically rely on grazing and receive minimal or no mineral supplementation, apart from common salt. (Garg et al., 2005). Additionally, the mineral content of locally available feeds and fodder varies, leading to region-specific mineral deficiencies.

CLASSIFICATION OF MINERALS:

Major or macro minerals (7) Required > 100 mg/day- Calcium (Ca), Phosphorus (P), Magnesium (Mg), Potassium (K), Sodium (Na), Chlorine (Cl), Sulfur(S)
Trace or micro minerals(10) Required < 100 mg/day- Copper (Cu), Zinc (Zn), Cobalt (Co), Fluorine (F), Iodine (I), Iron (Fe), Manganese (Mn), Selenium (Se), Chromium (Cr) , Molybdenum (Mo)
Occasionally beneficial minerals /Newer minerals (3)- Chromium, Boron (B), Lanthanum (La), Vanadium(V)
Type 1 minerals (Ca, Co, Cu, Fe and I) and Type 2 minerals (K, Mg, Zn, Na, P, S and Se).

(*N.F. Suttle 2022).

SOIL-PLANT-ANIMAL RELATIONSHIP:

Mineral status of livestock in different agro-eco zones (ICAR/AICRP/NDDB):

SOURCES OF MINERALS:

Cataloguing of common feeds and fodders based on mineral content

Calcium (Ca):

Good sources: 1-2% of the feed

Fodder/Legumes: Lucerne, cowpea
Top feeds: Glyrecidia leaves, mulberry leaves
Unconventional feeds: Sunflower heads, horse gram pods, groundnut haulms

Moderate sources: 0.7-1.0% of the feed

Fodder/grasses: Maize fodder, sorghum fodder, guinea grass, anjan grass, mixed local grasses
Oilseed cakes: Rapeseed cake, sunflower cake
Top feeds: Banana leaves, rain tree leaves
Unconventional feeds: Finger millet pods, gram husk, silk worm pupae meal, meat meal

Phosphorus (P):

Good sources: 1-3% of the feed

Oilseed cakes: Groundnut, coconut, cottonseed, soybean, sunflower, rape seed cake
By-products: Rice polish, wheat bran, rice bran
Unconventional feeds: Soya husk, meat and bone meal

Moderate sources: 0.5-1.0% of the feed

Fodder/grasses: Lucerne, velvet bean, para grass, blue panic, guinea grass
Oilseed cakes: Sunflower cake, neem seed cake, karanji cake, castor cake, rubber seed cake, guar meal
Unconventional feeds: Maize husk, rain tripods

Iodine (I):

Good sources: 0.1-0.7 ppm

Marine products, oilseed cakes, iodized common salt, yeast

Moderate sources: 0.10 ppm

Green fodders

Magnesium (Mg):

Good sources: 0.4-0.7% of the feed

Fodder/grasses: Cowpea fodder, Dina Nath grass
Oil cakes: Cottonseed cake, sunflower cake
By-products: Rice polish, rice bran
Top feeds: Glyrecidia
Unconventional feeds: Cocoa seed husk, groundnut haulms, seaweed

Moderate sources: 0.2-0.4% of the feed

Dry roughage: Ragi straw
Fodder/grasses: Cowpea fodder, hybrid napier, guinea grass, maize fodder, soybean fodder
Oilseed cakes: Rapeseed cake, castor cake, coconut cake, groundnut cake
Top feeds: Subabul leaves, mulberry leaves

Sulfur (S):

Good sources: 0.5-0.7% of the feed

Protein sources: Mustard cake, soybean meal, groundnut cake, meat meal

Moderate sources: 0.3-0.5% of the feed

By-products: Wheat bran, rice bran, rice polish

Manganese (Mn):

Good sources: 100-250 ppm

By-products: Wheat bran, rice bran
Crop residues: Paddy and ragi straw
Green fodder: Lucerne, cowpea

Moderate sources: 40-100 ppm

Green fodders, leafy vegetation

Selenium (Se):

Good sources: 0.4-0.6 ppm

Marine products, meat meal, Se-Yeast

Moderate sources: 0.3-0.4 ppm

Cultivated green fodders, legumes

Iron (Fe):

Good sources: 1000-5000 ppm

Legume fodders, cultivated green fodders, mixed local grasses, oilseeds, tree leaves, meat meal, top feeds

Moderate sources: 500-1000 ppm

Cereal green fodders, oil cakes and brans, tree leaves, dry fodders

Copper (Cu):

Good sources: 30-70 ppm

Legume fodders, tree leaves, castor cake, groundnut haulms

Moderate sources: 15-30 ppm

Local grasses, oil cakes, cereal by-products, top feeds

Zinc (Zn):

Good sources: 150-300 ppm

Legume fodder/grasses: Stylosanthus, anjan grass, guinea grass, Co-I fodder, soybean fodder
Oilseed cakes: Copra cake, neem seed cake
By-products: Wheat bran
Unconventional feeds: Tapioca meal, ginger waste, coffee husk, silk worm pupae meal, meat meal

Moderate sources: 50-150 ppm

Fodder/grasses: Rice bean fodder, Dina Nath grass, green panic, para grass, sorghum fodder
Oilseed cakes: Groundnut cake, cottonseed cake, sunflower cake, safflower cake
By-products: Rice polish
Top feeds: Banana leaves, gliricidia leaves, neem leaves
Unconventional feeds: Tapioca meal, sugarcane bagasse, subabul pods

These levels and sources provide guidance on meeting the mineral requirements of livestock in their feed. Please note that the specific requirements may vary depending on the type of livestock, growth stage, and specific local conditions. Consulting with a veterinarian or animal nutritionist is recommended for precise recommendations tailored to the specific needs of the animals. The information is based on studies by Gowda et al. (2004), Yadav et al. (2002), and Haldar et al. (2003).

Different sources of trace minerals have varying chemical characteristics, which can influence their bioavailability and effectiveness in animal nutrition. Here are the key characteristics of different sources of trace minerals:

Inorganic Mineral Source: Inorganic trace minerals are bound to groups like sulfates (SO4), chlorides (Cl), or oxides (O) through ionic bonds. These sources have been commonly used in feed-grade trace mineral supplementation due to their affordability and high solubility in the rumen.
Organic Mineral Source: Organic trace minerals are formed through chelation, where the metal ion is strongly bound to organic molecules (ligands) through covalent bonds, forming a ring structure. Organic mineral supplements can be marketed as complexes, chelates, or proteinates. These forms provide enhanced stability and protect the mineral element from unwanted reactions.
Nano Mineral Source: Nano minerals are manipulated to have particle sizes ranging from 1 to 100 nanometers. They have a larger surface area, allowing for better interaction with other biologically active substances in the digestive system. Nano minerals can exhibit improved assimilation and may have additional benefits, such as binding and removing toxins and pathogens.
Hydroxy Form: Hydroxy trace minerals are a recent advancement in mineral nutrition. They involve the formation of hydrolyzed inorganic metal complexes, where the trace metal is covalently bonded to hydroxy groups and chloride groups. The hydroxy group prevents the mineral from dissolving in the neutral pH of the rumen but dissociates at lower pH ranges in the abomasum and early portion of the small intestine.

ORGANIC TRACE MINERAL SOURCES:

"Trace minerals are nutritional elements added to production and companion animal diets in tiny quantities. They are essential for structural, physiological, catalytic, and regulatory functions in animals, making their inclusion in diets crucial for various reasons. Natural diets may not provide sufficient amounts of specific minerals to meet animal needs, the minerals in the feed may not be in a form that is easily absorbed, or anti-nutritional factors might decrease the proportion of the nutrient available for normal body functions." (AAFCO 2020).

Marked deficiencies are unlikely to occur in modern commercial production systems; however, marginal deficiencies could arise under certain conditions such as poor feed formulation or low feed intake. The occurrence and severity of mineral deficiencies are influenced by the duration of time that deficient diets are fed, prior mineral status, and the physiological state of the animals (Hill,2000).

What are Organic Trace Minerals?

Organic Trace Minerals, considered the third generation of trace minerals, are increasingly utilized globally. Their advantages stem from the chelates' unique chemical structure, consisting of central ions (or atoms) and ligands. In these compounds, the central ion is located in the centre and is surrounded by ligands in a specific spatial arrangement, connected by chemical bonds. The central ions, such as zinc, iron, copper, manganese, and chromium, are termed the forming bodies, while amino acids are ligands. This molecular structure results in stable compounds that are resistant to chemical reactions with other substances and exhibit excellent solubility in animals. Due to their moderate stability constant, these compounds are easily absorbed through the small intestinal mucosa of animals.

The main difference between organic and inorganic zinc sources is the presence of carbon. Inorganic sources lack carbon, while organic sources contain carbon and carbon-hydrogen bonds (Jahanian et al.,2010). Frequently, the terms "complex" and "chelate" are mistakenly used interchangeably. A metallic ion combined with a ligand forms a complex. This complex can be as simple as a single bond or can involve multiple bonds. When multiple bonds are present, it's specifically referred to as a chelate (Byrne et al.,2022).

What are Organic Trace Minerals? Organic Trace Minerals, considered the third generation of trace minerals, are increasingly utilized globally. Their advantages stem from the chelates

Definition of Organic Trace Minerals:

a).According to the Association of American Feed Control Officials (AAFCO), several types of organic trace minerals are defined as follows:

57.142 – Metal Amino Acid Chelate

This is produced from the reaction of a metal ion from a soluble metal salt with amino acids. It typically has a mole ratio of 1 mole of metal to 1-3 moles of amino acid (preferably 2) to form coordinate covalent bonds. The average molecular weight of the amino acids should be around 150 daltons, and the chelate's molecular weight should not exceed 800 daltons. When used as a commercial feed ingredient, it must be declared as a specific metal amino acid chelate.

57.150 – Metal Amino Acid Complex

This product results from complexing a soluble salt (such as potassium or manganese) with amino acids. The minimum metal content must be specified. When used commercially, it should be declared as a specific metal amino acid complex, such as potassium amino acid complex, copper amino acid complex, zinc amino acid complex, iron amino acid complex, cobalt amino acid complex, calcium amino acid complex, or manganese amino acid complex.

57.151 – Metal (Specific Amino Acid) Complex

This is formed by complexing a soluble metal salt with a specific amino acid, with the minimum metal content needing to be declared. When used in commercial feed, it should be declared as a specific metal, specific amino complex, such as copper lysine, zinc lysine, ferric methionine, manganese methionine, or zinc methionine.

57.23 – Metal Proteinate

This product results from chelating a soluble salt with amino acids and/or partially hydrolyzed proteins. It must be listed as a specific metal proteinate when used as a feed ingredient, such as copper proteinate, zinc proteinate, magnesium proteinate, iron proteinate, cobalt proteinate, manganese proteinate, or calcium proteinate.

57.29 – Metal Polysaccharide Complex

This is produced by complexing a soluble salt with a polysaccharide solution and must be declared as a specific metal complex, such as copper polysaccharide complex, zinc polysaccharide complex, iron polysaccharide complex, cobalt polysaccharide complex, or manganese polysaccharide complex.

57.28 – Metal Methionine Hydroxy Analogue Chelate

This results from the reaction of a metal salt with 2-hydroxy-4-methylthiobutanoic acid (HMTBa), with a chelated molar ratio of one mole of metal to two moles of HMTBa to form coordinate covalent bonds. This ingredient is used as a source of trace minerals and must be declared as a specific metal chelate for a metal methionine hydroxy analogue chelate.

57.160 – Metal Propionate

This is the product of the reaction between a metal salt and propionic acid, prepared with an excess of propionic acid at an appropriate stoichiometric ratio. It must be declared as a specific metal propionate when used as an ingredient, such as copper propionate or zinc propionate.

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b) According to the European Union (EU) definitions:

57.23 – Metal Proteinate

Form: Powder
Minimum Metal Content:

10% for copper, iron, manganese, and zinc

Chelation:

Minimum 50% for copper, iron, and manganese
Minimum 85% for zinc

Chemical Formula: M(x)1–3. nH₂O

M = metal
x = anion of protein hydrolysates containing any amino acid from soya protein hydrolysate

57.142 – Metal Amino Acid Chelate

Form: Powder
Minimum Metal Content:

10% for copper and zinc
9% for iron
8% for manganese

Chelation:

Metals and amino acids from soya protein are chelated via coordinate covalent bonds
Maximum 10% of the molecules exceeding 1500 Da

Chemical Formula: M(x)1–3. nH₂O

M = metal
x = anion of any amino acid from soya protein hydrolysate

57.151 – Metal (Specific Amino Acid) Complex

Form: Liquid or Powder

Liquid:

Minimum 6% for copper
Minimum 7% for zinc

Powder:

Minimum 15% for copper, iron, zinc, and manganese
Maximum moisture content:

13% for copper
10% for iron, zinc, and manganese

Chemical Formula: M(x)1–3. nH₂O

M = metal (Cu or Zn)
x = anion of glycine

Mode of action:

Minerals bonded to amino acids may potentially be absorbed more efficiently by the gut wall, although conclusive evidence is still lacking. For instance, a study demonstrated that adding methionine to a human diet doubled copper absorption (Goff, 2018). The mechanisms of absorption for bonded metals remain uncertain: some studies suggest that the metal separates from the ligand during absorption, while others propose that the metal-ligand complex is absorbed intact. Research by Gao et al. (2014) strongly suggested that amino acid-bonded metals are absorbed more readily and possibly through non-standard inorganic transporters, based on findings using Caco cells in vitro. Another supplier's research indicated that their glycinates were absorbed more effectively than sulfates in a similar model. However, it remains unclear whether these observations hold universally true across different conditions and biological systems.

In general, chelates are categorized based on their stability constants (Qf values). Here's a breakdown:

- Chelates with a Qf value below 10 are considered weakly chelated.

- Moderately strong chelates typically have Qf values in the range of 10 to 100.

- Chelates with Qf values above 100 are considered strongly chelated.

The stability constants indicate how tightly the metal ion is bound to the ligands (such as amino acids) in the chelate complex. A higher Qf value generally suggests greater stability and resistance to dissociation, which can influence the bioavailability and effectiveness of the chelated mineral in animal nutrition (Cao et al.,2000 & Byrne et al.,2022).

Points to be considered while selecting an organic trace mineral:

Bond strength
Chemical form and purity of the mineral sources
Differences in dissociation rates of the mineral form from the ligand
Particle size of the mineral
Processing conditions/manufacturing method
Solubility
Stability
Bioavailability

In poultry diets, selecting the optimal form of organic minerals is critical for maximizing nutrient utilization and overall bird health:

Bioavailability and Absorption: Choose organic minerals with high bioavailability and proven absorption rates in poultry species, ensuring efficient utilization of essential nutrients.
Chelate Stability: Prioritize forms with stable chelation properties, indicated by moderate to strong stability constants (Qf values), which support resilience through digestive processes.
Formulation Compatibility: Select mineral forms (e.g., amino acid chelates, amino acid complexes, proteinates) that integrate smoothly into poultry feed formulations, enhancing dietary consistency and efficacy.
Supplier Reliability: Source from reputable suppliers known for quality assurance and transparency in product specifications, ensuring reliability in nutrient content and performance.
Cost-Effectiveness: Balance the benefits of enhanced mineral bioavailability and poultry performance against the cost of the chosen organic mineral source, optimizing overall feed efficiency and economic viability.

By prioritizing these factors in poultry nutrition, producers can effectively enhance nutrient uptake, growth rates, and overall health outcomes in their flocks.

MINERAL REQUIREMENT:

Nutrient requirement for Layers and Broiler (BIS 2007) and Mineral Mixtures for Supplementing Cattle Feeds (BIS 2002)

Nutrient requirement for Layers and Broiler (ICAR 2013)

MINERAL INTERACTION:

Mutual antagonisms between copper, cadmium and zinc lead to complex three-way interactions. The primary mechanisms whereby minerals interact to affect bioavailability are:

Formation of unabsorbable complexes in the gut (e.g. metal phytates).
Competition between cations for a divalent cation transporter (Fe and Mn).
Competition between anions for common absorption channel and
Induction of non-specific metal-binding proteins (ferritin by Fe and metallothionein by Cu, Zn or Cd).

Metal distancing: a concept advanced to indicate mechanisms by which potential competition between elements that share transport proteins is limited: transporters include divalent metal transporter 1 (DMT1) and copper transporter 1 (CRT1); bold symbols indicate elements with a a relatively strong affinity for a carrier.

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The synergism of minerals in the gastrointestinal tract renders the following interaction mechanisms possible.

1.Direct interaction between elements (Ca with P, Na with Cl, Zn with Mo), the level of absorption is determined by their proportions in the humus and the diet.

2.Interaction through the intermediary of the phosphorylation processes in the intestinal wall and the activity of digestive enzymes (e.g., the effect of P, Zn, and Co on their liberation from the feed and the absorption of other elements).

3.Indirect interaction by stimulating the growth and activity of the microflora in the forestomachs and in the intestine (stimulation of rumen microflora by cobalt, accompanied by intensification of biosynthetic processes).

Various mechanisms of synergistic interaction are also possible at the tissue and cell metabolism level.

1.Direct interaction between elements in structural processes (between Ca and N in the formation of bone hydroxyapatite, joint participation of Fe and Cu in the formation of haemoglobin, interaction of Mn with Zn in the conformation of RNA molecules in the liver).

2.Simultaneous participation of elements in the active centre of some enzyme (Fe and Mo in xanthine and aldehyde oxidases, Cu and Fe in cytochrome oxidase).

3.Activation of enzyme systems and intensification of synthetic processes requiring the presence of other minerals (activation of synthetases by Mg2 +, with subsequent participation of P, S, and other elements in the synthesis).

4.Activation of the functions of the endocrine organs and effect (by way of hormones) on the metabolism of other macro- or microelements (iodine—> thyroxine —> intensification of anabolic processes —> retention of potassium and magnesium in the body).

Antagonistic interactions may also proceed by several different mechanisms. In particular, inhibition of absorption of some elements by others in the digestive tract may proceed by the following mechanisms.

1.A simple chemical reaction between the elements (formation of magnesium phosphate in the presence of excess magnesium in the diet; reaction between copper and sulfate; formation of the triple Ca-P-Znsalt in the presence of high concentrations of calcium in the diet).

2.Adsorption on the surface of colloidal particles (fixation of Mn and Fe on particles of insoluble magnesium or aluminum salts).

3.The effect of inhibitor ions with an antimetabolic function (B, Pb, Tl, etc.) on oxidative phosphorylation in the wall, juice separation, and enzyme activity; this effect interferes with the breakdown of feed ingredients and the liberation and absorption of inorganic ions.

4.Competition for ions acting as material carriers in the intestinal wall. In the process of tissue metabolism, in which minerals are mainly present in the form of ions, the following antagonistic interaction mechanisms are possible.

Direct interaction of simple and complex inorganic ions (e.g., copper - molybdenum).
Competition between ions for the active centers in the enzyme systems (Mg and Mn2+ in metalloenzyme complexes of alkaline phosphatase, Cholinesterase, enolase, etc.).
Competition for the bond with the carrier substance in the blood (Fe2+ competing with Zn2+ for the bond with plasma transferrin).
Activation by ions of enzyme systems with opposite functions (activation by copper ions of ascorbate oxidase, which oxidizes ascorbic acid vs. activation by zinc and manganese ions of lactonases which promote the synthesis of this vitamin).
Antagonistic effect of different ions on a given enzyme (activation of ATPase by Mg2+ and its inhibition by Ca2 ).
'Softening' of the toxic effect of heavy metals present in feeds and in the animals' bodies by ions of biotic elements (e.g., reduction of the lead concentration in the body by the addition of copper, zinc, and manganese).

Mineral turnover:

Minerals follow labyrinthine pathways through the animal once ingested.
Mineral turnover rates vary from tissue to tissue but are generally high in intestinal mucosa and liver, intermediate in other soft tissues and slow in bone.
Mineral turnover is measurable from rates of change in specific radioactivity in selected pools after a single intravenous radioisotope dose.

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Bioavailability: Definition

Bioavailability refers to the extent to which a nutrient from a specific source is absorbed and becomes available at the tissue level, rather than just remaining at the dietary level. It is also referred to as biological availability, bioactivity, bio potency, or bioefficacy (Ammerman et al., 1995).

ARC (1981) defines (bio)availability as the fraction that is retained in the body [feed - (feces + urine)]. The term (bio)availability is also used in studies assessing the nutritive value of mineral sources, whereby the result is compared with a reference that is assumed to be 100% available (NRC, 1998).

Bioavailability refers to the extent to which an ingested nutrient from a specific source is absorbed and can be utilized in the animal's metabolism. Multiple researchers, including Forbes and Erdman (1983), Sauberlich (1987), and Southgate (1988), have provided similar definitions of bioavailability. However, it is important to demonstrate the utilization of the nutrient within the normal metabolic processes of the animal to establish its true bioavailability, as emphasized by other investigators such as Fox et al. (1981) and O'Dell (1984). Bioavailability is not an inherent property of the assessed material but rather an estimated value obtained through experiments that consider absorption and utilization under specific test conditions (Fairweather-Tait, 1987). Bioavailability values are commonly expressed as percentages.

The bioavailability of minerals and trace elements is context-specific, dependent on factors such as the specific form, valence, or spin of the mineral and its compatibility with particular locations or enzyme systems in the body. It refers to the proportion of the ingested nutrient that is absorbed and utilized for normal physiological functions. Different elements serve distinct roles, such as iron (Fe) being incorporated into metalloproteins like hemoglobin, while calcium (Ca) and magnesium (Mg) contribute to the structural integrity of bones and teeth. Most elements are essential components of various enzyme systems, such as selenium (Se) in glutathione peroxidase. Physiological requirements for inorganic nutrients vary significantly based on age, sex, growth stage, pregnancy, and lactation. Dietary requirements are determined by considering both physiological needs and the efficiency of nutrient absorption from the diet, which can range from less than 1% to nearly 100%.

The components of bioavailability are:(Suttle et al., 2010; Ammerman et al., 1995)

Accessibility: Potential access of dietary minerals to absorption sites.
Digestibility/absorbability: Capacity of the gut mucosa to uptake and transfer accessible minerals.
Retainability: Potential retention of transferred minerals by the body [feed – (feces + urine)](Partridge, 1980).
Functionality: Potential for retained minerals to enter functional forms in tissues.

ABSORPTION OF MINERALS:

In principle, the trans-epithelial transport consists of both, an active trans-cellular component that can be regulated and/or a passive para-cellular component that depends on chemical and electrical gradients existing across the intestinal wall.

Passive transport through the gut wall is mediated by hormonal control that is primarily based on their concentration in the extracellular fluid. Before absorption by the absorbing enterocytes from the gastrointestinal tract, the minerals must become available in ionic form (as cations and anions), which is suitable for uptake and transport. Most absorption of trace minerals occurs in the small intestine, primarily in the duodenum, although absorption can occur anywhere along the GI tract. Copper and zinc can also be absorbed in the rumen. In poultry, the proventriculus is also a potential site for absorption.

Mineral absorption takes place via two routes:paracellular absorption at high dietary doses and transcellular absorption at lower concentrations. Diffusion over tight junctions or via solvent drag, and the migration with water flow between intestinal cells are examples of paracellular absorption. Mineral transporters are required to transmit minerals across the apical and basolateral membranes of enterocytes during transcellular absorption.

The availability of minerals in an ionized form at the apical membrane of enterocytes, which is required for transcellular absorption, is a typical barrier to mineral absorption. These processes can be hampered by external factors, and transcellular absorption becomes critical when dietary mineral levels are inadequate.

Minerals complexed with food components such as amino acids and peptides can potentially be absorbed via solvent drag if they are soluble in the water layer above the tight junction and have a molecular weight of less than 3.5 kDa.

At lower food quantities, transcellular absorption is the primary mechanism of mineral absorption, which needs transport proteins to carry the minerals over the apical membrane. However, when fed in excess, these same minerals can contribute to the formation of free radicals that promote oxidative stress (Goff 2018).

1. Para-cellular Transportation:

Diffusional force created by differences in the ionized mineral concentration on each side of the tight junction push the mineral through the tight junction into the interstitial space. Crossing of minerals depends on:

The concentration of minerals in the luminal surface
Freely ionized state of minerals can only be transported
Dissolved amount in the fluids overlying the luminal side
The size of the mineral atom
Electrical charge difference

The image demonstrates the cellular structure of enterocytes in the gastrointestinal system and several ways of mineral absorption:

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Tight junction proteins connect enterocytes. Ions (shown as Y+) can diffuse through tight junction pores, crossing tight junctions and entering the interstitial space (IS) during paracellular absorption. Minerals dissolved in water (shown as Z) can also pass through the tight junction with the bulk flow of water, a process known as solvent drag. Transcellular absorption, on the other hand, involves particular mechanisms that allow minerals (such as X+) to pass the apical membrane, move through the cytoplasm of the cell, and eventually bridge the basolateral cell membrane into the IS and lamina propria. From there, the minerals can enter the bloodstream for distribution throughout the body.

2. Solvent Drag Transport:

Mineral ions suspended in the water can be absorbed.
Minerals complexed (AA, peptides, VFA) can also be absorbed.
Solvent drag can also move minerals out into the lumen
The bulk flow occurred in the upper small intestine than in the lower small intestine. This may be due to the presence of larger water pores in the upper intestine.

3. Transcellular Transport:

Transport is selective to transport channel
Transport channels consist of specialized proteins in the cell membrane
The more the channel opens more the minerals get absorbed.

The mineral doesn't determine the mechanism rather gut does to facilitate intake.
The more you offer options, the more you can get the ways for transport.

Factors Influencing Bioavailability and Methods for Improving Mineral Utilization in Farm Animals:

A. Evaluation of Bioavailability:

Bioavailability methods suitable for one element may be totally unsuitable for another element. Use of a standard source allows expression of bioavailability in terms of relative biological availability . This approach results in a number referred to as the “relative bioavailability value” or RBV (Miles et al 2000,Ammerman et al., 1995).

1.Reference/Standard Source

Littell et al. (1995) recommend that bioavailability studies employ a readily available reference standard. In the case of sulphates, for example, commercially available forms such as pentahydrate Cu(II) sulphate, hepta- and monohydrate Fe(II) sulphate, and monohydrate Zn and Mn sulphate are advised. Choosing less prevalent forms diminishes the value of the data and makes comparisons with other research more complex.

2. Model Selection

Most statistical assays of bioavailability use regression models and in recent years, the majority of estimates for the relative bioavailability of different mineral sources have been commonly obtained through slope-ratio assays. The slope of the regression line obtained from animals fed the test source of mineral is compared with that from animals fed a reference source.Other assays include parallel lines, three-point, mean ratio and standard curve.

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3.Absorption And Chemical Balance

1.Measuring Absorbability:

Apparent absorption : Mineral values have been most commonly measured as differences between intake and faecal excretion of mineral in balance or ‘digestibility’ trials, i.e. the fractions ‘apparently’ absorbed (AA). By adding inert, unabsorbable markers such as chromic and titanium oxides to poultry diets, disappearance of mineral from the gut can be measured before digesta reach the cloaca: ‘pre-caecal digestibility’ (PCD), the equivalent of AA, is being widely measured. Such markers colour the faeces, allowing faecal collection to be synchronized with feeding period. Apparent absorption is of limited value for elements such as calcium, phosphorus, zinc, manganese, and copper for which the gastrointestinal tract is a major pathway of excretion.

STTD (Standardized total tract digestibilities) became the recommended method for describing availability of P in pigs (NRC, 2012) and poultry (WPSA, 2013), for which SPCD is the equivalent term.

True Absorption: True absorption represents total intake minus total fecal excretion (tot. fecal exc.) from which total endogenous has been subtracted.The value for true absorption is greater than that for apparent absorption and is a more valid estimate of the amount of a mineral element presented to body tissues for metabolic purposes. Total endogenous fecal excretion can be estimated by use of an appropriate radioisotope (Kleiber et al, 1951; Underwood, 1981).

Urinary Excretion:Urine is a major pathway of excretion for some minerals such as magnesium,iodine, and potassium but is a minor pathway for others such as manganese, iron,

zinc, and copper. Urinary excretion is a useful indicator of absorption for magnesium and potassium and other elements with similar excretion characteristics.

Net Retention: Net retention, [referred to as "net availability" by Underwood (1981)] is definedas total intake minus total excretion (total fecal plus total urinary) of the element.

4.Stable Isotope Techniques:

Example: Isotope Dilution Technique

Administer a known amount of stable isotope-labeled mineral (e.g., zinc-65) to an animal.
Collect blood samples from the animal at specific time intervals and measure the isotopic ratio of the labeled mineral.
By comparing the isotopic ratio in the administered dose with the ratio in the blood samples, the absorption and bioavailability of the mineral in the animal can be determined.

5.Whole Body Counting:

Example: Calcium-47 Measurement

Administer a known amount of radioactive calcium-47 to an animal.
Use radiation detection techniques to measure the radioactivity emitted by calcium-47 in the whole body of the animal.
The level of radioactivity indicates the amount of absorbed calcium and provides insights into its bioavailability.

6.Tissue Analysis:

Example: Bone Mineral Density Measurement

Use imaging techniques like dual-energy X-ray absorptiometry (DEXA) or micro-computed tomography (micro-CT) to measure bone mineral density in animals.
Assess the mineral content in specific bones or tissues of interest.
Changes in bone mineral density provide insights into the bioavailability and utilization of minerals like calcium or phosphorus in the animal's body.

7.Biomarkers:

Here are some examples of biomarkers for studying individual mineral regulation:

Calcium:

Calcium-sensing receptor (CaSR) mRNA expression
Vitamin D receptor (VDR) mRNA expression
Parathyroid hormone (PTH) mRNA expression

Phosphorus:

Sodium-dependent phosphate transporter (NaPi-IIb) mRNA expression
Fibroblast growth factor 23 (FGF23) mRNA expression
Phosphate-regulating gene with homologies to endopeptidases on the X chromosome (PHEX) mRNA expression

Iron:

Divalent metal transporter 1 (DMT1) mRNA expression
Hepcidin mRNA expression
Transferrin receptor 1 (TfR1) mRNA expression
Ferritin

Zinc:

Zinc transporter 1 (ZnT1) mRNA expression
Metallothionein mRNA expression (Varun et al 2007)
Zinc-regulated transporter (ZRT) and iron-regulated transporter (IRT)-like protein (ZIP) mRNA expression
Superoxide dismutase (SOD)

Copper:

Copper transporter 1 (CTR1) mRNA expression
ATP7A mRNA expression
Ceruloplasmin mRNA expression
Superoxide dismutase (SOD)
Copper chaperone for SOD (CCS) ( Gowda et al 2013)

Selenium:

Selenoprotein mRNA expression (e.g., glutathione peroxidase, selenoprotein P)
Selenium transporter (selenoprotein H, SLC30A10) mRNA expression

Manganese:

Manganese superoxide dismutase (MnSOD) mRNA expression
Manganese transporter (SLC30A10) mRNA expression

Chromium:

Chromium transporter (SLC30A10) mRNA expression

Iodine:

Sodium-iodide symporter (NIS) mRNA expression
Thyroid peroxidase (TPO) mRNA expression
Thyroglobulin mRNA expression

Molybdenum:

Molybdenum cofactor sulfurase (MOCOS) mRNA expression
Molybdenum transporter (MOT1) mRNA expression

Transcriptomics, Proteomics ,Metabolomics : Potenital molecular tools for precise detection of mineral status , DNA microarrays and PCR assays.

Unlocking the Secrets of Bioavailability and Utilization of Minerals in Farm Animals - Image 6

*Structure of Metallothionein trapping upto 7 Zinc ions together

8.Choice of Response Criteria:

Measuring the deposition or storage of minerals into selected tissues such as tibia or plasma for Zn, liver for Cu or tibia for Mn was the most common output in trace mineral relative bioavailability experiments. More recently, the use of mineral-responsive biomarkers, such as changes in gene or protein expression, or the activity of a mineral-dependent enzyme, have become more common.

Commonly used indices of mineral element adequacy are as follows ( Gowda et al 2013):

- Growth rate

- Blood and plasma/serum concentrations

- Hair, wool, hoof concentrations

- Biopsy tissue concentrations

- Enzyme concentrations and activities

- Physiological functions

- Chemical balance

- Mobilizable stores/Turnover rates

- Immune competence

-Behaviour and appearance

9.In vitro techniques:

So far, this approach has not resulted in satisfactory results, because it is very difficult to simulate the gastric and intestinal conditions properly.
With these tests, only inferior sources can be distinguished from good quality sources.
Recently developed a method known as the TNO Intestinal Model (TIM) that simulates gastro-intestinal conditions and claims to be able to accurately simulate absorption conditions including minerals.
In vitro solubility of supplemental mineral sources in several solvents has been used to estimate the degree to which the source would be utilized by animals.Solvents have included water, .4% HCl, 2% citric acid, neutral ammonium citrate, ruminal fluid, artificial ruminal fluid, and abomasal fluid. Generally, in vitro solubility is a poor indicator of in vivo bioavailability.

The study by Hamdi et al. (2014) examined the effects of different calcium sources and levels of non-phytate phosphorus (NPP) on the growth and bone health of Ross male broiler-chicks. They found that calcium chloride resulted in higher calcium digestibility compared to limestone or tricalcium phosphate (TCP). The source of calcium did not affect phosphorus digestibility, but higher levels of added phosphorus from monocalcium phosphate improved its digestibility. The study also showed that broiler-chicks achieved better growth and bone mineralization when fed diets with low-soluble calcium sources. They recommended a NPP level of 0.35%-0.40% with a high dose of phytase for optimal performance and bone formation in broiler chickens from day 0 to day 14, regardless of the calcium source used (limestone or TCP).
A study by Fernandes et al. (1999) examined the average availabilities of different phosphate sources in Hubbard chicks. The phosphate sources used were SP (standard calcium phosphate dibasic dihydrate), FP (feed-grade phosphate), and AP (agricultural grade phosphate). The study found that the average availabilities varied for different parameters. For body weight, FP had an average availability of 100.6% and AP had an availability of 107.6%. In terms of bone ash, FP had an availability of 88.3% and AP had an availability of 93.2%. For bone solubility, FP had an availability of 84.2% and AP had an availability of 96.3%. However, when using radiolabeled bone phosphate, both FP and AP had similar average availabilities of 100.0% and 99.9%, respectively. These findings provide insights into the utilization of different phosphate sources in Hubbard chicks.
According to a study by Matin et al. in 2021, when it comes to broiler chickens, black soldier fly larvae (BSFL) meals and partially-defatted BSFL have high phosphorus (P) availability based on digestibility and retention rates, ranging from 73% to 88%. However, the relative bioavailability of phosphorus based on bone ash is lower, approximately 20% to 30% lower than the values obtained from digestibility and retention. This suggests that while broiler chickens are able to efficiently digest and retain phosphorus from BSFL, the actual utilization and incorporation of phosphorus into bone ash may be somewhat limited. This information highlights the importance of considering different factors when assessing the nutritional value and bioavailability of phosphorus from black soldier fly larvae meals in broiler chicken diets.

“Phosphate rock is indeed a non-renewable and exhaustible natural resource that takes millions of years to form through geological processes. The increasing demand for phosphates is expected to continue, with an estimated annual growth rate of 1-1.5% until 2030, and then slowing down to 0.9% per year between 2030 and 2050 (FAO, 2002)”.

To exploit phosphate in a sustainable way, the livestock sector can adopt several measures:

Reducing phosphorus requirements in feed supplements: This can be achieved by using low-phytin feeds, which contain lower levels of phytic acid. Phytic acid binds with phosphorus, making it less available for absorption by animals.
Use of artificial enzymes like phytase: Phytase is an enzyme that breaks down phytic acid, increasing the availability of phosphorus in feed for animals. This helps improve phosphorus utilization and reduces the need for high-phosphorus supplements.
Productive use of manures and organic materials: Manures and farmyard organic materials can be effectively used as fertilizer supplements, as they contain significant amounts of phosphorus. Proper management and recycling of these materials can reduce the reliance on synthetic phosphate fertilizers.
Exploring alternative phosphorus sources: Other sources of phosphorus, such as bone meal, blood meal, and fishmeal, can be utilized. These sources have high concentrations of phosphorus and can serve as valuable supplements. Techniques like water soaking, the addition of vitamin D, and boron usage can further enhance the availability and utilization of phosphorus from these sources (Cordell et al., 2009)

RBV tables of Magnesium:

RBV tables of Cobalt:

RBV tables Sodium:

RBV tables of Potassium:

RBV tables of Sulphur:

RBV tables of Copper:

RBV tables of Iodine:

RBV tables of Iron:

RBV tables of Selenium:

RBV tables of Manganese:

RBV tables of Zinc:

RBV tables of Molybdenum:

The RBV tables and studies conducted by Ammerman (1995), McDowell (1992), Lesson (2005), and Byrne et al. (2022) provide evidence supporting the notion that organic trace minerals (OTM) exhibit comparable or superior bioavailability compared to their inorganic counterparts. This implies that OTM enables a greater absorption of minerals, resulting in enhanced mineral status within animals. In predicting the bioavailability of chelated and complexed metals, specific chemical characteristics are deemed significant. These include chelation effectiveness, which refers to the strength of the bonds formed between an organic ligand and a metal, and the proportion of the organic ligand remaining bound to the metal under physiological pH conditions. By considering these factors, it becomes possible to estimate the bioavailability of chelated and complexed metals in animal systems. These findings underscore the potential advantages of utilizing OTM in animal nutrition for optimizing mineral uptake and utilization.

MINERAL SUPPLEMENTATION STRATEGIES:

When considering mineral supplementation strategies, several factors come into play. The choice of mineral source is influenced by factors such as purity, unit cost, stability in the feed, availability to the animal, particle size for ease and safety of mixing, absence of harmful impurities (e.g., cadmium and fluorine), compatibility with other ingredients (including vitamins), risk of toxicity (often inversely related to availability), and residual effects on human consumption and the environment.

Free-access supplementation allows animals to consume minerals freely, while slow-release formulations can provide a sustained release of minerals over time. The selection between inorganic and chelated (organic) mineral sources is also a consideration. Type 1 minerals exhibit a prolonged initial depletion phase and a terminal phase of specific clinical disorders when deficient, while Type 2 minerals show immediate entry into the deficiency phase with early non-specific signs of terminal disorders.

Overall, it is important to choose mineral sources that meet the specific requirements of the animals, considering their availability, effectiveness, and potential impacts on animal health, human consumption, and the environment. Regular monitoring and adjustment of mineral supplementation strategies are essential to maintain optimal mineral status and prevent deficiencies or toxicities in animals. (*Suttle et al., 2022).

A good quality ASMM (Animal Supplementary Mineral Mixture) should possess the following characteristics:

Higher Bioavailability and Absorption: The minerals in the ASMM should be chosen from a source that offers higher bioavailability and absorption, ensuring optimal utilization by the animal.
Combination of Inorganic and Chelated Minerals: In areas where there is a documented deficiency of trace minerals, a portion of the ASMM can consist of chelated minerals (e.g., Cu Met, Zn Met). Generally, a ratio of 2/3 inorganic minerals to 1/3 chelated minerals is recommended for ruminants.
Consideration of Factors in Mineral Source Selection: Factors such as easy availability in the area, cost, stability, and type of diet should be taken into account when selecting the source of minerals for the ASMM.
Compatibility and Solubility: Minerals in the ASMM should be compatible with each other and with the animal's diet, and they should have sufficient solubility to ensure proper utilization by the animal's tissues.
Particle Size, Density, and Chemical Stability: Particle size, density, and chemical stability of the minerals should be considered to ensure ease of handling, proper mixing, and long-term stability of the ASMM.
Controlled Fluoride and Silica Levels: The ASMM should have controlled fluoride levels, not exceeding 0.06%, to prevent toxicity. The silica content should not exceed 3-4%, and the moisture content should not exceed 5%.
Separation from Vitamin Supplements: ASMM should not be mixed with vitamin supplements to avoid oxidation and maintain the stability and effectiveness of both.
No Animal-Origin Ingredients: According to the Bureau of Indian Standards (BIS), ASMM should not contain any ingredient of animal origin, even in trace amounts. This is done to protect livestock from diseases such as Mad Cow Disease or Bovine Spongiform Encephalopathy (BSE).

By considering these characteristics, a good quality ASMM can be formulated to effectively supplement the mineral requirements of animals while ensuring safety and optimal utilization.

TANUVAS SMART (Specific Mineral Array for Regions of Tamilnadu) is a mineral supplementation strategy developed by Tamil Nadu Veterinary and Animal Sciences University (TANUVAS) specifically for the regions of Tamil Nadu, India. It aims to address the mineral deficiencies prevalent in the local animal population by formulating a customized mineral mixture.

The TANUVAS SMART strategy takes into consideration the specific mineral requirements of animals in Tamil Nadu based on factors such as soil composition, forage availability, and common mineral deficiencies observed in the region. By analyzing these factors, a mineral array is designed to meet the specific needs of animals in that particular area.

Unlocking the Secrets of Bioavailability and Utilization of Minerals in Farm Animals - Image 7

Interrelationship of Minerals with Rumen Microbial Activity:

The interrelationship of minerals with rumen microbial activity is crucial for maintaining proper rumen fermentation and microbial function. Here are the key points regarding the interrelationship of minerals with rumen microbial activity:

Osmotic Pressure: Minerals, along with volatile fatty acids (VFAs), contribute to rumen osmolarity. High osmotic pressures can impair cellulose degradation and feed intake. Excessive addition of major minerals to the diet can depress rumen fermentations by affecting osmolality.
Buffering Capacity: Minerals, such as sodium (Na) and potassium (K) bicarbonates, along with VFAs, play a role in buffering the rumen. Imbalance or low levels of minerals can impact microbial activity and ruminal fermentation.
Dilution Rate: Addition of mixed salts similar to those found in artificial saliva can increase dilution rate in the rumen. This alteration in fermentation pattern can lead to an increase in acetic acid and a decrease in propionic acid production.
Nitrogen (N) Metabolism: Minerals, particularly phosphorus (P), affect nitrogen metabolism in the rumen, leading to enhanced nitrogen retention in ruminants.
Functions of Major Minerals: Major minerals regulate physicochemical characteristics of the rumen environment, including osmotic pressure, buffering capacity, redox potential, and dilution rate. These factors influence rumen fermentations and microbial activity.
Specific Mineral Functions:

Phosphorus (P): Essential for carbohydrate fermentation, nucleotide synthesis, coenzyme formation, and cellulolytic activity.
Magnesium (Mg): Required for cell membrane integrity, enzyme activation, and nucleic acid synthesis. It affects cellulolytic activity and is involved in preserving rumen pH.
Calcium (Ca): Involved in cell wall structure, enzyme activation, and acid neutralization. High levels of dietary Ca can affect soluble inorganic P content in the rumen.
Potassium (K) and Sodium (Na): Essential for protein synthesis and glycolysis in microorganisms.
Iron (Fe): Needed for the synthesis of many enzymes during microbial growth, particularly involved in electron transfer.
Manganese (Mn): Required for glycolysis, citric acid cycle reactions, and as a cofactor in many enzymes. It can replace magnesium in certain enzymatic reactions.
Zinc (Zn): Essential for various microbial enzymes and plays a role in adherence of cellulolytic bacteria to feed fiber.
Cobalt (Co): Required for vitamin B12 synthesis and functioning of cobalamin-dependent enzymes.
Other trace elements: Molybdenum (Mo), selenium (Se), nickel (Ni), and copper (Cu) are essential for specific microbial functions.

Excessive Amounts of Trace Minerals: Excessive levels of trace minerals can have inhibitory effects on cellulolytic activity, fermentation pattern, and protein synthesis. Some trace elements can depress rumen protein concentration, decrease VFA production, and alter fermentation proportions. Protozoal growth is often more sensitive to excess trace elements than bacterial growth. (Ramsawroop and Sandeep Kumar 2021).

IMPROVING BIOAVAILABILITY OF MINERALS:

Organic trace minerals are distinct from ITM due to their mineral bonding ability.
Stability constants or formation constants are commonly used to provide an indication of the strength of interaction between a metal and the ligand in a chelate or complex.(Martell et al 1996)
In general, chelates with a Qf value below 10 are considered weakly chelated; moderately strong chelation values are in the range of 10 to 100, and strongly chelated values are those above 100. (Cao et al 2000)
Sources with moderate and high chelation strengths had the highest relative bioavailability, whereas those with weak chelation strengths were found to be only as available as their inorganic sulphate forms at best. (Yu et al 2010 , Wang et al 2012 , Liao et al 2019)

Here are the observations regarding the effect of mineral supplementation in different animals:

Cows:

Cu, Zn, Mn: Similar milk yield and composition, similar body weight, no effect on uterine health, and similar plasma variables. (Yasui et al., 2014)
Zn-amino acid complex: Decreased postpartum dry matter intake, increased colostrum IgG concentrations, improved feed efficiency, decreased services per conception, and decreased milk fat concentration. (Nayeri et al., 2014)

Cows:

Cu, Zn, Mn-polysaccharide complex: Reduced number of days in open, increased conception rate, no change in milk yield and composition, increased colostrum immunoglobulins, increased milk fat, lower calf mortality, and increased services per conception. (Chester-Jones et al., 2013)

Bulls:

Cu, Zn, Mn, Co: Increase in motile sperm, increase in progressive sperm, and increase in sperms with rapid motility. (Rowe et al., 2014)

Rams:

Cu, Zn-methionine: Reduction in dry matter intake, increased ceruloplasmin and ALP, no effect on growth, and increased immunity. (Gowda et al., 2014)

Kids:

Cu-methionine: No effect on growth, no effect on nutrient intake and digestibility, and increased Cu balance. (Waghmare et al., 2014)

Rams:

Cu, Zn-methionine: No effect on body weight, reduced sperm motility, reduced motile sperm count, no effect on semen volume, no change in nutrient intake and digestibility, and increased wool yield. (Shinde et al., 2012)

Ewes:

Cu, Zn-methionine: Marginally lower dry matter intake, no effect on nutrient digestibility and growth, higher bioavailability, and reduced fecal mineral excretion. (Pal et al., 2014).

Here are the observations regarding the effect of mineral supplementation in different poultry and pig species:

Layers:

Cu, Mn, Zn proteinates: Lower egg loss, higher shell thickness, and increased shell strength. No change in egg weight, feed intake, feed conversion, specific weight, and Haugh unit of eggs. (Stefanello et al., 2014)

Poultry:

Zn proteinate: No effect on tibia and liver mineral content, increased immune response, and no change in feed intake and feed conversion ratio. (Mandal et al., 2011)

Poultry:

Cr propionate: No effect on intake and weight gain, increased milk fat, lowered serum corticosterone level in heat-stressed poultry, and improved recoup in blood glucose level. (Rajalekshmi et al., 2012)

Poultry:

Cu, Zn, Mn, Fe: Decreased dry matter intake at 50% level, increased feed conversion ratio, increased tibia mineral concentration, and similar glutathione peroxidase and ferric reducing ability in blood plasma. (Rao et al., 2013)

Poultry:

Mineral proteinates: Higher retention rate and bioavailability, avoidance of Cu and Zn antagonism, no effect on phytase, and less mineral wastage and decrease in pollution. (Ao and Pierce, 2013)

Quail:

Fe, Zn-methionine: No effect on growth, nutrient intake, and feed conversion ratio, and increased bioavailability. (Sannamani et al., 2013)

Pig:

Organic Zn: No effect on growth but increased antioxidant level. (Hill et al., 2014)

Pig:

Cu(HMTBa)2: Increased feed intake, feed efficiency, and liver Cu level. (Zhao et al., 2014).

HYDROXY TRACES MINERALS:

The bioavailability of a mineral depends on factors such as accessibility, absorbability, retainability, and functionality.

In the case of copper, studies have shown that the bioavailability of copper hydroxychloride is higher compared to copper sulfate when added to cattle diets high in copper antagonists, such as molybdenum and sulfur. This increase in bioavailability could be attributed to the lower interaction of hydroxy copper with molybdenum and sulfur in the rumen due to its low solubility at neutral pH. However, when evaluated in copper-depleted cattle supplemented with diets low in molybdenum, the bioavailability of hydroxy copper was similar to copper sulfate.

Similarly, research by Vanvalin et al. (2019) indicated an increase in the relative bioavailability of hydroxy copper (112%) compared to an inorganic source (set as 100%) based on liver copper concentrations. This suggests that hydroxy copper is more efficiently absorbed and incorporated into liver copper stores. In commercial broiler chicks, Luo et al. (2005) found that copper from the hydroxy form had a slope ratio of 109.0% for bioavailability compared to copper sulfate.

Regarding zinc, Zhang and Guo (2007) evaluated the bioavailability of zinc in hydroxy form compared to zinc oxide (ZnO) in weanling piglets. Based on plasma, liver, kidney, and metacarpal zinc concentrations, the relative bioavailability of zinc in hydroxy form was 159%, 125%, 128%, 123%, and 122% respectively, compared to ZnO. This suggests that hydroxy zinc could be a desirable source of zinc in weanling piglet diets, as it enhances growth performance even at lower dosages (1500 ppm) compared to higher dosages of ZnO (3000 ppm). The increased bioavailability of hydroxy zinc may be attributed to its higher solubility in the acidic environment of the gastrointestinal tract.

Similarly, Shaeffer et al. (2017) estimated the bioavailability of zinc in growing steers from two different sources, namely ZnOHCl and ZnSO4. Supplementing 25 mg of zinc per kilogram of dry matter from ZnOHCl and ZnSO4 resulted in increased zinc bioavailability in steers supplemented with ZnOHCl, as reflected by higher plasma zinc concentrations. This higher bioavailability of zinc from the hydroxy form relative to ZnSO4 may be associated with its lower solubility in the rumen.

The cost of elemental Zn and Cu from different sources is as follows:

Zn sulfate: $3.82/kg of Zn (approximately 282.38 INR/kg of Zn)
Cu sulfate: $10.48/kg of Cu (approximately 775.09 INR/kg of Cu)
Zn amino acid complex: $32.14/kg of Zn (approximately 2,376.41 INR/kg of Zn)
Cu amino acid complex: $52.90/kg of Cu (approximately 3,909.59 INR/kg of Cu)
Zn hydroxychloride: $11.14/kg of Zn (approximately 822.45 INR/kg of Zn)
Basic Cu chloride: $15.20/kg of Cu (approximately 1,125.60 INR/kg of Cu)

From an economic perspective, it is vital to assess the cost-effectiveness of these trace mineral sources. While organic sources (amino acid complexes) tend to have higher production costs, the hydroxy form of minerals stands out as a more cost-effective option. It is relatively less expensive compared to organic forms and is comparable in cost to inorganic sources like sulfate and chloride. (Reddy et al 2021).

BIO-FORTIFICATION:

Zinc bio-fortification, whether applied through foliar spraying or soil application, has proven to be an effective strategy for addressing zinc deficiency in humans, as highlighted by Bhatt et al. (2020). By enhancing the zinc content in crops, such as sorghum fodder, the bioavailability and absorption of zinc in the human gut can be improved.

According to the findings of Gridhar et al. (2021), digestibility trials have demonstrated an increased absorption of zinc in the gut when consuming bio-fortified sorghum fodder. Moreover, the study indicated that the liver serves as a natural storage organ for zinc.

The research also revealed that sheep fed bio-fortified sorghum fodder exhibited higher levels of plasma zinc (compared to those fed non-fortified fodder), resulting in a significant increase in the activity of zinc-dependent enzymes, such as superoxide dismutase (SOD), in the plasma. Specifically, the SOD activity was measured at 15.5 units/min for sheep fed bio-fortified sorghum fodder, whereas it was recorded at 10.3 units/min for those fed non-fortified fodder (with the difference being statistically significant at p< 0.05).

These findings highlight the positive impact of zinc bio-fortification on improving zinc absorption, increasing plasma zinc levels, and enhancing the activity of zinc-dependent enzymes in animals. These effects indicate the potential for bio-fortified crops to contribute to addressing zinc deficiency in both human and animal populations, thus promoting better health and well-being.

ENCAPSULATED TECHNOLOGY

In brief, the purpose of microencapsulation includes the following (Desai and Park2005):

To protect the core material from degradation and to reduce the evaporation rate of the core material to the surrounding environment.
To modify the nature of the original material for easier handling.
To ensure slow, regulated and targeted release of active ingredient
To mask unwanted flavor or taste of the core material.
To reduce nutrient interaction with other ingredients
To ensure uniform mixing due to dilution with the matrix and in powder form
To improve the bioavailability, stability and efficacy of product
·Top of Form

Microencapsulation is a process used to encapsulate or coat small particles or droplets of substances with a protective coating or matrix. This can be achieved using various methods categorized into chemical, physical, and physicochemical methods. Some common methods for microencapsulation include:

Chemical Methods:

Solvent Evaporation: In this method, the core material to be encapsulated is dissolved in a solvent, and the solution is then emulsified in a coating material. The solvent is subsequently evaporated, leaving behind the coated particles.
Interfacial Cross-linking: This method involves the formation of cross-links between polymers at the interface of the core material and the coating material, resulting in the formation of a solid shell.
Interfacial Polycondensation/Interfacial Condensation Polymerization: It involves the reaction between two reactive monomers or pre-polymers at the interface of the core and coating materials, leading to the formation of a polymer shell.
Matrix Polymerization: In this method, the core material is dispersed within a monomer or pre-polymer, which is then polymerized to form a solid matrix encapsulating the core.

Physical Methods:

Spray Drying: The core material is dispersed in a coating material and sprayed into a hot drying chamber, where the solvent evaporates, resulting in the formation of dry encapsulated particles.
Pan Coating: The core material is placed in a rotating pan, and the coating material is gradually added while the pan is rotated, leading to the formation of a coating layer on the core particles.
Fluid-Bed Coating: The core material is suspended in a fluidized bed, and the coating material is sprayed onto the particles as they are fluidized, resulting in the formation of a coated layer.
Centrifugal Extrusion: The core material is extruded through a nozzle while being subjected to centrifugal forces, causing it to be coated with the coating material.
Vibrating Nozzle/Vibrating-Jet: The core material is forced through a vibrating nozzle or jet, and the coating material is simultaneously sprayed onto the vibrating core, resulting in encapsulation.

Physicochemical Methods:

Ionotropic Gelation: It involves the complexation of oppositely charged polymers or the gelation of polysaccharides in the presence of multivalent ions to form a gel-like coating around the core material.
Polyelectrolyte Complexation: It utilizes the interaction between oppositely charged polyelectrolytes to form a coating around the core material.
Phase Separation/Coacervation: This method involves the separation of a polymer solution into two phases, resulting in the formation of a polymer-rich phase that encapsulates the core material.
Supercritical Fluid Technology: It utilizes supercritical fluids, such as carbon dioxide, to dissolve the coating material, which is then sprayed onto the core material. Upon depressurization, the supercritical fluid evaporates, leaving behind the coated particles. Source: Tomaro-Duchesneau et al. (2012).

In a study conducted by Nageswara Rao et al. (2023), encapsulated zinc oxide (ZnO) with 66% efficiency and a 20% ZnO core showed comparable results in terms of weight gain, feed intake, and feed conversion ratio (FCR) among different groups of broilers. Zinc supplementation at 50% in either encapsulated or organic form maintained growth performance, as well as serum, tissue, and bone mineral content in the broilers.

During the starter phase, the broilers that were fed encapsulated trace mineral premixes exhibited better FCR compared to those on inorganic trace mineral (ITM) supplementation, and the encapsulated premix with a composition of M-375 showed superior FCR compared to organic trace mineral (OTM) supplementation. Throughout the overall growth cycle, broilers receiving encapsulated trace minerals showed similar growth performance to those fed with ITM and OTM, but they excreted significantly lower amounts of copper (Cu), manganese (Mn), and zinc (Zn) into the litter. However, there were no differences observed in tibia ash content and tibia breaking strength among the groups.

The findings of this study suggest that encapsulated zinc oxide, when supplemented at 50% in either encapsulated or organic form, can effectively maintain growth performance and ensure adequate mineral content in broilers. Furthermore, the use of encapsulated trace mineral premixes can improve FCR during the starter phase and reduce mineral excretion into the litter, thereby potentially minimizing environmental pollution.

NANOMINERALS

Ganjigohari et al.2018 examined the replacement of calcium carbonate with different concentrations of nano-sized calcium carbonate (CaCO3) in laying hens. They observed a reduction in egg production percentage and egg mass as the concentration of nano-sized calcium carbonate decreased. Additionally, the concentration of calcium in the blood decreased at the lowest concentration.
Hassan et al.2016 studied the effects of nano-sized dicalcium phosphate (DCP) supplementation in male broiler chicks. They found that higher concentrations of nano-sized DCP improved average daily gain (ADG) and feed conversion ratio (FCR) by about 12%. Moreover, the excretion of calcium and phosphorus was decreased at the lowest concentration of nano-sized DCP.
Mohamed et al.2016 investigated the effects of nano-sized DCP supplementation in male broiler chicks. They observed that nano-sized DCP supplementation resulted in greater tibia weight, length, width, and breaking strength. However, there was a slight decrease in carcass weight, and no significant effects were observed on the weights of the liver, heart, and gizzard.
Ramesh 2014 examined the use of nano-sized DCP and copper sulfate supplementation in laying hens. They found that reducing the amount of DCP and copper sulfate through the use of nanoparticles did not negatively affect body weight, egg production, egg mass, and eggshell quality compared to the control group.
Sohair et al.2017 studied the effects of hydroxyapatite nanoparticles (NP) supplementation in broilers. They observed improved average daily gain (ADG) and feed intake with no significant effects on nutrient digestibility.
Vijayakumar and Balakrishnan 2014 investigated the replacement of dicalcium phosphate (DCP) with nano-sized DCP in male broiler chicks. They found that higher levels of nano-sized DCP led to higher feed intake, greater ADG at certain percentages of replacement, and the best feed conversion ratio (FCR) at a specific level of replacement.
Wang et al 2017. examined the effects of nano-sized calcium carbonate (CaCO3) supplementation in laying hens through diets or drinking water. They found that nano-sized calcium carbonate supplementation reduced blood pH but had no significant effects on rectal temperature and egg production rate. Additionally, stronger eggshell strength and better egg freshness index were observed with a specific inclusion of nano-sized calcium carbonate in the drinking water
Abedini et al.2017 investigated the effects of zinc oxide nanoparticles (ZnO NP) supplementation in laying hens. They found that replacing a portion of calcium carbonate with ZnO NP resulted in no significant effects on feed intake, egg production, and feed conversion ratio (FCR). However, egg mass increased with ZnO NP supplementation compared to regular ZnO. Additionally, ZnO NP had positive effects on tibia bone resistance and increased the concentration of zinc in the tibia, liver, and eggs. They also observed increased superoxide dismutase (SOD) activity in the liver and decreased malondialdehyde (MDA) content in the eggs.
In another study by Abedini et al., 2018 laying hens were supplemented with ZnO NP at different levels. They found that ZnO NP supplementation resulted in greater ash weight, egg mass, eggshell thickness, and shell strength. There was also an improvement in the Haugh unit (a measure of egg quality) and bone-breaking strength. Moreover, ZnO NP supplementation increased activities of SOD in the liver, pancreas, and plasma, while reducing MDA content in the eggs.
Bami et al.2016 compared different levels of ZnO and ZnO NP supplementation in broiler chickens. They found no significant effects on feed intake, ADG, and FCR. However, ZnO NP supplementation at a specific level resulted in reduced coliform bacteria, decreased MDA content, and improved cooking loss in meat.
Fathi et el 2015 examined the effects of ZnO NP supplementation in broiler birds. They found increased ADG at all doses and decreased FCR at a specific dose. Additionally, ZnO NP supplementation resulted in reduced plasma and liver MDA levels in birds exposed to low ambient temperature. However, it also led to a decrease in mortality due to induced ascites at higher doses.
Mohammadi et al.3028 investigated the effects of ZnO NP supplementation in broiler birds. They found that ZnO NP supplementation had varied effects on different parameters, such as increased percentage of broiler carcass in wet diet, increased relative weight of certain organs, and no effect on other carcass characteristics. They also observed no significant effects on antibody titer, lipid peroxidation, and blood cell numbers.

Overall, these studies demonstrate the diverse effects of zinc nanoparticle supplementation on poultry production parameters, including growth performance, bone strength, egg quality, lipid profile, immune response, and antioxidant status. The findings highlight the potential benefits of using zinc nanoparticles in poultry nutrition, but further research is needed to optimize dosage and assess long-term effects.

Probiotic strains such as Bacillus subtilis, Enterococcus faecium, lactic acid-producing bacteria, B. licheniformis, Lactobacillus sporogenes, and Clostridium butyricum have been found to improve tibia (bone) health in animals. They enhance tibia ash content, calcium percentage, indexes, thickness, and breaking strength. These probiotics achieve this by producing phytase, improving gut morphology, increasing absorption area, and reducing intestinal pH (Yaqoob et al., 2022).

Egg Enrichment:

Selenium (Se): Enriched eggs can contain around 500 µg/kg (30-40 µg/egg) of selenium when hens are supplied with 0.3 to 0.5 mg/kg of selenium from sources like selenomethionine or Se-enriched yeast.
Iodine (I): Yolk and albumen concentration of iodine can be increased by providing hens with dietary iodine supplementation ranging from 3 to 24 mg/kg, resulting in egg content of 10 to 78 µg I/egg.
Iron (Fe): Enrichment of iron in eggs is limited, with a maximum increase of around 10-20% observed when hens are provided with dietary iron supplementation at levels of 100 to 300 mg/kg.
Zinc (Zn): Increasing dietary zinc levels from 30 to 150 mg/kg can enhance zinc levels in eggs by approximately 25%.

Poultry Meat Enrichment:

Selenium (Se): Dietary supplementation of selenium in ducks resulted in breast meat levels ranging from 0.05 to 0.87 mg/kg and thigh meat levels ranging from 0.04 to 0.64 mg/kg, depending on the dietary levels of selenium.
Iron (Fe): Supplementation of 100 to 200 mg Fe methionine/kg in poultry diets increased Fe content in breast meat by 39% and in liver by 32%. FeSO4 supplementation at 200 mg/kg increased thigh content by 13% and liver content by 17%.
Zinc (Zn): Dietary zinc levels had limited influence on zinc content in poultry meat.

NEWER MINERALS:

In a study conducted by Adarsh et al. (2021), it was found that supplementation of 40 ppm boron (Boron) to a calcium-inadequate diet improved laying performance in layers, suggesting the beneficial role of boron in addressing abiotic stress conditions.
For bacterial urease activity in the rumen, nickel (Ni) is required for optimal functioning. However, the presence of Ni may not provide a significant advantage in terms of urea metabolism, as noted by Milne et al. (1990).
Silicon (Si) is considered essential for growth and bone development in rats and chicks. It is believed to be involved in glycosamine and collagen synthesis, as suggested by Carlisle (1986).
Supplementation of vanadium (V) at a level of 0.1 ppm has been found to increase growth rate, red blood cell (RBC) count, and hemoglobin levels in calves, as reported by Drebickas et al. (1989).
Although chromium (Cr) availability from feedstuffs is generally low, practical diets for livestock are considered to contain sufficient amounts of Cr to meet the animals' requirements, according to Spears (1999). However, supplementation of Cr in the form of Cr-picolinate to ruminants and pigs has been shown to improve feed efficiency, as demonstrated by studies conducted by Chang et al. (1991) and Amoikon et al. (1995).

Unlocking the Secrets of Bioavailability and Utilization of Minerals in Farm Animals

Impact of Trace Mineral Status on Biological Function:

CLASSIFICATION OF MINERALS:

SOURCES OF MINERALS:

Cataloguing of common feeds and fodders based on mineral content

Calcium (Ca):

Phosphorus (P):

Iodine (I):

Magnesium (Mg):

Sulfur (S):

Manganese (Mn):

Selenium (Se):

Iron (Fe):

Copper (Cu):

Zinc (Zn):

ORGANIC TRACE MINERAL SOURCES:

What are Organic Trace Minerals?

Definition of Organic Trace Minerals:

**57.142 – Metal Amino Acid Chelate**

**57.150 – Metal Amino Acid Complex**

**57.151 – Metal (Specific Amino Acid) Complex**

**57.23 – Metal Proteinate**

**57.29 – Metal Polysaccharide Complex**

**57.28 – Metal Methionine Hydroxy Analogue Chelate**

**57.160 – Metal Propionate**

b) According to the European Union (EU) definitions:

57.23 – Metal Proteinate

57.142 – Metal Amino Acid Chelate

57.151 – Metal (Specific Amino Acid) Complex

Mode of action:

In general, chelates are categorized based on their stability constants (Qf values). Here's a breakdown:

Points to be considered while selecting an organic trace mineral:

MINERAL REQUIREMENT:

MINERAL INTERACTION:

Mineral turnover:

Bioavailability: Definition

The components of bioavailability are:(Suttle et al., 2010; Ammerman et al., 1995)

ABSORPTION OF MINERALS:

1. Para-cellular Transportation:

2. Solvent Drag Transport:

3. Transcellular Transport:

A. Evaluation of Bioavailability:

1.Reference/Standard Source

2. Model Selection

3.Absorption And Chemical Balance

1.Measuring Absorbability:

4.Stable Isotope Techniques:

5.Whole Body Counting:

6.Tissue Analysis:

7.Biomarkers:

8.Choice of Response Criteria:

9.In vitro techniques:

MINERAL SUPPLEMENTATION STRATEGIES:

Interrelationship of Minerals with Rumen Microbial Activity:

IMPROVING BIOAVAILABILITY OF MINERALS:

HYDROXY TRACES MINERALS:

BIO-FORTIFICATION:

ENCAPSULATED TECHNOLOGY

NANOMINERALS

Egg Enrichment:

Poultry Meat Enrichment:

NEWER MINERALS:

Transitioning to Zero ZnO: Phileo’s nutritional strategy

E.S.E. & INTEC

57.142 – Metal Amino Acid Chelate

57.150 – Metal Amino Acid Complex

57.151 – Metal (Specific Amino Acid) Complex

57.23 – Metal Proteinate

57.29 – Metal Polysaccharide Complex

57.28 – Metal Methionine Hydroxy Analogue Chelate

57.160 – Metal Propionate