The proportion of the element consumed that is utilized for a biochemical or physiologic function (O’Dell, 1997)

A measure of the proportion of the total amount of a nutrient that is utilized for normal body functions (Fairweather-Tart, 1999)

The degree to which an ingested nutrient in a particular source is absorbed in a form that can be utilized in metabolism by the animal (Ammerman et al., 1995)

The fraction of the ingested nutrient that is utilized for normal physiological functions or storage (Jackson, 1997)

Intestinal absorption (major barrier)

Transport to site of action

Cellular uptake

Incorporation into a biochemically active form

Frataxin

Heme

CCS

Superoxide Dismutase

Chaperone Proteins

Incorporation into biological Incorporation into biological processesprocesses

Transport Proteins

Transferrin

Ceruloplasmin

ExtracellularIntracellular

Small Intestine

Cu

Fe

Intrinsic or Physiological Factors that Influence Bioavailability

1) Species and Genetics

2) Age and Sex

3) Metabolic Function – growth, lactation, maintenance

4) Nutritional Status

5) Intestinal or Rumen Microflora

6) Physiological Stress

Extrinsic or Dietary Factors that Influence Bioavailability

1) Solubility of element – CuS, CuMoS4

2) Binding to other dietary components (fiber, silica) in the intestine3) State of Oxidation – Fe+2 vs. Fe+3

4) Competitive Antagonisms of similar ions5) Chelation effects – Can be positive or negative depending on the solubility and dissociation constant of the complex formed.

Tissue Utilization

Dietary Cu

Biliary Cu

Cu Transporters

Total Fecal Cu

Unabsorbed &EndogenousCu

Absorbed Cu

Intestinal absorption changes in a situation of excessive mineral consumption verses normal

Paracellular

Absorption

Dietary Zn, Fe

Normal mineral consumptionExcessive mineral consumption

Zn & FeZn & Fe

Passive DiffusionHigh

Supplemental Zn (mg/kg)

0a 5 40

Gain, g/d 70b 140c 150c

Serum Zn, mg/L 0.18b 0.59c 1.00d

Serum alkaline phosphatase, U/L 45b 137c 175c

aBasal diet analyzed 3.7 mg Zn/kg.b,c,dP < 0.05.

Droke and Spears, 1993

Species Criterion

Pigs Growth, Bone and Plasma Zn, Plasma Alkaline Phosphatase

Chicks Growth, Bone Zn

Ruminants Growth, Plasma Zn, Plasma Alkaline Phosphatase

Adequate Deficient

Plasma diamine oxidase, U/L 127.8 61.5

Ceruloplasmin, mg/dL 33.6 6.6

Plasma copper, mg/L 1.3 0.4

Liver copper, mg/kg 178.1 4.6

Legleiter and Spears, 2007

Species Criterion

Nonruminants Bile Cu? Plasma Diamine Oxidase?

Ruminants Plasma and liver Cu, Plasma Ceruloplasmin

Plasma Diamine Oxidase

Feedstuff Ca P Na K Mg Mn Fe Cu Zn Se

Fescue hay 0.41 0.30 0.02 1.96 0.16 97.00 132.00 22.00 35.00  

Alfalfa hay 1.40 0.28 0.05 2.43 0.28 30.30 198.00 7.30 18.80 0.41

Corn silage 0.25 0.22 0.01 1.14 0.18 23.50 131.00 4.18 17.70 0.53

Soybean meal 0.25 0.60 0.04 1.97 0.27 27.50 120.00 28.00 60.00 0.1

Corn gluten feed 0.07 0.95 0.26 1.40 0.40 22.10 226.00 6.98 73.30 1.8

Soybean hulls 0.53 0.18 0.03 129.00 0.22 10.00 409.00 17.80 48.00 0.14

Corn 0.30 0.32 0.01 0.44 0.12 7.89 54.50 2.51 24.20 0.6

Barley 0.05 0.35 0.01 0.57 0.12 18.30 59.50 5.30 13.00 1.16

Mineral composition of feedstuffs

Hale and Olson, MU Epub

Minerals Forms in Plants

Zinc Anionic complexes; fiber associated; phytate complexes

Copper Neutral or anionic complexes; fiber associated; phytate

Selenium Selenomethionine; selenite; selenate

Iron Ferritin; porphyrins; anionic complexes; ferric hydroxide

Manganese Largely unknown

Iodine Iodide ion

Molybdenum Molybdate ion

Mineral Supplement Empirical formula Mineral concentration (percent)

Relative bioavailability (RV)

Mineral availability (percent of content)

Calcium Calcium carbonate CaCO3 38 100.00 38.00Bone meal variable 24 110.00 26.40Calcium chloride (dihydrate)

CaCl2(H2O) 31 125.00 38.75

Dicalcium phosphate Ca2(PO4) 20 110.00 22.00Limestone   36 90.00 32.40Monocalcium phosphate

Ca(PO4) 17 130.00 22.10

Cobalt Cobaltous sulfate CoSO4(H2O)7 21 100.00 21.00Cobaltic oxide Co3O4 73 20.00 14.60Cobaltous carbonate CoCO3 47 110.00 51.70Cobaltous oxide CoO 70 55.00 38.50

Copper Cupric sulfate CuSO4(H2O)5 25 100.00 25.00Copper EDTA variable variable 95.00 variableCopper lysine variable variable 100.00 variableCupric chloride (tribasic)

Cu2(OH)3 Cl 58 115.00 66.70

Cupric oxide CuO 75 15.00 11.25Cupric sulfide CuS 66 25.00 16.50Cuprous acetate CuC2O2H3 51 100.00 51.00

Iodine Potassium iodide KI 69 100.00 69.00Sodium iodide NaI 84 100.00 84.00Calcium iodate Ca(IO)3 64 95.00 60.80Diiodosalicyclic acid C7H4I2O3 65 15.00 9.75Ethylenediamine dihydriodine

C2H8N2(HI)2 80 105.00 84.00

Pentacalcium orthoperiodate

Ca5(IO6)2 39 100.00 39.00

Iron Ferrous sulfate heptahydrate

FeSO4(H2O)7 20 100.00 20.00

Ferric citrate variable variable 110.00 variableFerric EDTA variable variable 95.00 variableFerric phytate variable variable 45.00 variableFerrous carbonate FeCO3 38 10.00 3.80

Cupric sulfate CuSO4(H2O)5

25 100.00 25.00

Copper EDTA variable variable 95.00 variableCopper lysine variable variable 100.00 variableCupric chloride (tribasic)

Cu2(OH)3 Cl 58 115.00 66.70

Cupric oxide CuO 75 15.00 11.25Cupric sulfide CuS 66 25.00 16.50Cuprous acetate CuC2O2H3 51 100.00 51.00

Supplement Empirical formulaMineral concentration (percent)

Relative bioavailability (RV)

Mineral availability (percent of content)

0

0.5

1

1.5

2

2.5

0 50 100 150

Daily Individual Cu Intake, mg/d

Lo

g L

iver

Cu

, mg

/kg

Cu sulfate

Cu glycinate

Linear (Cu sulfate)

Linear (Cu glycinate)

499/332 = 150% RVB

P < 0.01

Mineral Supplement Empirical formula

Mineral concentration (percent)

Relative bioavailability (RV)

Mineral availability (percent of content)

Magnesium Magnesium sulfate

MgSO4 20 100.00 20.00

Magnesium acetate

MgC2O2H4 29 110.00 31.90

Magnesium basic carbonate

MgCO3 31 100.00 31.00

Magnesium oxide

MgO 55 100.00 55.00

Manganese Manganese sulfate

MnSO4(H2O) 30 100.00 30.00

Manganese carbonate

MnCO3 46 30.00 13.80

Manganese dioxide

MnO2 63 35.00 22.05

Manganese methionine

variable variable 125.00 variable

Manganese monoxide

MnO 60 60.00 36.00

Phosphorus Sodium phosphate

NaPO4 variable    

Bone meal variable 21 100.00 21.00Defluorinated phosphate

variable 12 80.00 9.60

Dicalcium phosphate

CaHPO4 18 85.00 15.30

Selenium Sodium selenite Na2SeO3 45 100.00 45.00Cobalt selenite variable variable 105.00 0.00Selenomethionine

variable variable 245.00 0.00

Selenoyeast variable variable 290.00 0.00Sodium Sodium chlorideNaCl 40 100.00 40.00

Sodium bicarbonate

Na(CO3)2 27 95.00 25.65

Zinc Zinc sulfate ZnSO4(H2O) 36 100.00 36.00Zinc carbonate ZnCO3 56 60.00 33.60Zinc oxide ZnO 72 100.00 72.00

Minerals must be soluble at site of absorption

Information on trace mineral bioavailability from feeds is based on GIT solubility

Copper Zinc

0a 72 h 0a 72 h

------------ % of total -------------

Alfalfa 88.9 92.9 25.8 79.4

Rhizoma peanut 50.6 89.6 18.1 80.5

Dwarf elephantgrass 84.4 94.3 7.3 75.5

Bermudagrass 69.9 75.8 43.1 62.1

Bahiagrass 63.1 81.7 33.8 53.0

Limpograss 70.0 69.5 26.6 67.2

aAmount disappearing following washing with water.Emanuele and Staples, 1990

Availability of minerals in feedstuffs◦ Chemical forms◦ Fiber

Dietary antagonisms◦ Effect on feedstuff mineral vs. supplemented mineral

Increasing absorption and/or reducing excretion if intake of a mineral is low or marginal relative to the requirement

Reducing absorption and/or increasing excretion if intake of a mineral is above the requirement

Dietary zinc (mg/kg)

39.5 16.6

Net 65Zn absorptionb 34.8c 53.4d

Milk zinc 65Znb 6.3c 14.4d

mg Zn/d 60 52

Net 65Zn retentionb 28.5c 39.0d

aCows were fed diets for 6 weeks. 65Zn was given orally on week 5 and followed for 14 days.b% of 65Zn dose.c,d (P < 0.01).

Neathery et al., 1973

Dietary zinc (mg/kg)

Tissue 39.5 16.6

---------- mg/kg DM ----------

Liver 119 109

Heart 80 75

Lung 81 88

Ovaries 74 71

Muscle 102 109

Rib, cartilage 54a 44b

a,b(P < 0.01)

Neathery et al., 1973

Selenite-selenium absorption in ruminants is much lower than in nonruminants

Selenomethionine is the predominant form of selenium that occurs naturally in feedstuffs

Treatment

Control Selenite Selenomethionine RBV

Plasma glutathione peroxidase, U/mg protein

Day 0 1.95 1.81 1.87

Day 28 2.38 5.03 6.05 138

Day 56 3.34 6.67 7.16 115

aControl diet analyzed 0.04 ppm of Se. Selenium wassupplemented at 0.05 ppm from d 0 to 28 and 0.10 ppm from d 29 to 56.

Treatment

Control Selenite Selenomethionine RBV

Glutathione peroxidasea

Heart 280 494 509 107

Kidney 119 304 304 100

Liver 15 59 86 161

Muscle 22 37 50 186

Tissue seleniumb

Heart 0.50 0.86 1.00 139

Kidney 3.41 6.47 5.23 59

Liver 0.35 0.80 1.28 206

Muscle 0.12 0.26 0.31 133

aU/mg protein.bµg/g dry tissue.

Research regarding ruminant bioavailability of minerals from feeds is extremely limited

A portion of certain trace minerals in forages appears to be associated with the fiber fraction

Based on in situ studies, a high proportion of trace minerals are released from forages in the rumen

Mineral sources differ in bioavailability which may impact supplementation needs