Agenda

1
Agenda

• (1) Overview of Minerals
• General Functions
• Deficiencies
• Toxicities
• (2) Macrominerals
• Calcium
• Phosphorus
• Magnesium
• Sodium Chloride
• Potassium
• Sulfur

• (3) Trace Minerals
• Iron
• Copper
• Zinc
• Manganese
• Cobalt
• Chromium
• Iodine
• Selenium
• Molybdenum
• Fluoride

2
Overview of Minerals
Pages 53-56 in textbook
3
Minerals in Feeds

• Found in all feedstuffs
• More reliably found in animal products
• Improved absorption
• Often other substances in foods decrease
  absorption (bioavailability) of minerals
• Oxalate, found in spinach, prevents absorption of
  most calcium from that feedstuff
• Phytate, form of phosphorous in most plants,
  makes it poorly available

4
Minerals

• Minerals are essential when removal of the
  mineral from the diet results in an abnormality
  that disappears when the mineral is added back
• Many minerals are toxic at relatively low levels
  of intake, including
• Non-essential mercury, lead
• Potentially essential arsenic, cadmium
• Essential copper, selenium, iron
• All minerals are toxic at high levels

5
General Functions

• 4 total body weight
• Not changed by digestion or metabolism
• Involved in body structure components of several
  hormones, vitamins, or other compounds
• Ca, P, and Mg
• 99 of whole-body Ca content in bones and teeth
• Involved in acid-base and water balance
• Na, K, P, and Cl
• Maintenance of a pH of 7.357.40

H3PO4 ? H2PO4 H ? HPO42 2H ?
PO43 3H
CO2 H2O ? HCO3 H ? H2CO3
6
General Functions

• Component or activator of
• Enzymes
• Compounds (e.g., ATP) involved in biochemical
  reactions

Item Mineral Glutathione peroxidase Se Hemoglobin
Fe Thyroid hormones I Vitamin B12 Co Cofactors,
activators Ca2, Mn2, Mg2
7
Excretion or Secretion of Minerals

• Urine
• Excretion of absorbed minerals
• Feces
• Excretion of absorbed and non-absorbed minerals
• Bile
• Direct secretion into large intestines
• Sweat
• Secretion - especially sodium and chloride
• Milk, eggs

8
Factors Affecting Requirements

• Species or breed of animal
• copper and sheep vs. pigs and cattle
• Rate of growth or physiological state
• Lactation, egg production
• Chemical form of the mineral
• Availability, solubility
• Ionic form necessary for absorption
• Inorganic vs organic forms
• Na selenite vs Na selenate vs selenomethionine
• (poorly absorbed to best absorbed)
• Levels of other minerals
• Interactions (e.g., Cu/Zn, Ca/Mg/Zn)

9
Mineral Interactions

• Examples
• Excess phosphorus impairs calcium absorption
• Manganese excess can induce iron deficiency
• Iron deficiency exacerbates lead poisoning
• Molybdenum deficiency exacerbates copper toxicity
• Molybdenum excess induces copper deficiency
• High levels of zinc, calcium or iron can reduce
  copper absorption

10
Mineral Interactions
11
Deficiencies and Excesses

• Most minerals have an optimal range
• Below leads to deficiency symptoms
• Above leads to toxicity symptoms
• Mineral content of soils in many cases dictates
  mineral status of plants used for many feeds
• May take many months to develop
• Time impacted by body stores

12
Deficiency to Toxicity
Growth
Abnormality Death
Mineral consumption
13
Toxicity Margin for Safety
Narrow Wide range range
Growth
Mineral consumption
14
Requirements and Toxicities
15
Classification

• Macro or major minerals
• Sodium, potassium, magnesium, calcium,
  phosphorus, sulfur, chloride
• Present in body tissues at concentrations gt50
  mg/kg (50 ppm)

• Micro or trace minerals (body needs relatively
  less)
• Chromium, manganese, iron, cobalt, molybdenum,
  copper, zinc, fluoride, iodine, selenium,
  silicon, tin, arsenic, nickel
• Present in body tissues at concentrations lt50
  mg/kg (50 ppm)

16
Classification of Minerals

• Macrominerals
• Calcium - Ca
• Phosphorus - P
• Sodium - Na
• Chloride - Cl
• Potassium - K
• Magnesium - Mg
• Sulfur - S

17
Classification of Minerals

• Microminerals
• Cobalt - Co
• Iodine - I
• Iron - Fe
• Molybdenum - Mo
• Selenium - Se
• Zinc - Zn

• Copper Cu
• Chromium Cr
• Nickel Ni
• Fluorine F
• Silicon Si
• Manganese - Mn

18
Macrominerals
Pages 53-56 in textbook
19
Macro-Mineral Supplementation
20
Calcium Sources

• Minerals
• Limestone, dicalcium phosphate
• Animal sources
• Meat and bone meal, fish meal
• Milk products
• Roughages
• But not cereal grains

21
Calcium

• Most abundant mineral in animal tissues
• Lots of functions
• Bone structure
• Nerve function
• Blood clotting
• Muscle contraction
• Cellular metabolism

22
Calcium (Ca)

• Functions
• Bone/teeth formation and maintenance
• 99 of body calcium
• In 21 ratio with phosphorus in hydroxyapatite
  Ca5(PO4)3OH
• Soft tissues
• Enzyme activation
• Blood clotting
• Muscle contraction
• Transmission of nerveimpulses to muscle
• Calcium binds to troponin C

23
Calcium Absorption

• From duodenum and jejunum
• Active or passive
• Dependent on vitamin D stimulates calbindin in
  small intestinal cells and enhances absorption
• Absorption depends on need
• Particularly high during growth, pregnancy and
  lactation
• Bioavailability decreased by
• Phytates (grains)
• Wheat bran
• Low estrogen levels (postmenopausal women)
• High fat diets (form soaps with fatty acids)

24
Calcium (Ca)

• Dietary ratio of 11 to 21 ideal for most
  animals (except for laying hen, optimal ratio is
  131 Canonphytate phosphorous)
• Never want P gt Ca

Grains tend to be low in calcium while forages
are moderate to high
25
Calcium Regulation

• Three hormones involved in regulation
• Vitamin D3
• from kidney
• Parathyroid hormone (PTH)
• from parathyroid gland
• Calcitonin
• from thyroid gland
• PTH and vitamin D3 act to increase plasma Ca,
  while calcitonin acts to decrease plasma Ca

26
GI Tract
Dietary Ca
Fecal Ca
Endogenous Ca
Absorbed Ca

1,25(OH)2D3 from kidney
Blood Ca
Sweat Ca
Urinary Ca
-

Ca Apposition
Ca Resorption
PTH
Calcitonin
Plasma Ca
Parathyroid Gland
Bone Ca
Plasma Ca
27
Calcium Deficiency - Causes

• Low calcium intake or absorption
• Soap formation (fatty acids) in rumen
• Competition with divalent ions for absorption
• Abnormal CaP ratio (21)
• High calcium and low phosphorus leads to
  formation of insoluble CaPO4 in intestinal lumen
• High phosphorus (and low calcium) also inhibits
  absorption
• Vitamin D deficiency

28
Calcium Deficiency - Symptoms

• Reduced growth or production rate
• Egg-shell strength
• Rickets
• Young, fast-growing animals
• Misshapen bones, enlarged joints, lameness
• Osteoporosis
• Decalcification of bone and loss of bone mass
• Estrogen involved, bone mass decreases following
  menopause
• Isoflavones (estrogen-like compounds) in soy help
  alleviate losses

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Osteoporosis

• Decrease bone mass
• Related to aging, poor diet, and estrogen loss
• Leads to 1.5 million bone fractures per year
• Slender, inactive women who smoke are at highest
  risk
• Type I (postmenopausal)
• Type II (senile)

31
Bone Strength

• Depends on bone mass
• Related to age, gender, activity level and
  genetics
• Peak bone mass in women achieved by age 20-30
• Same in females of all mammalian species peak
  mass achieved as animal reaches maturity and then
  decreases thereafter
• Cannot increase bone density after this point,
  but can slow rate of bone density loss
• By age 65, some women have lost 50 of bone mass

32
Calcium Deficiencies

• Rickets
• in growing animals
• Osteomalacia and osteoporosis
• in adult animals
• Milk fever (parturient paresis)
• in lactating animals

33
Calcium Deficiency Milk Fever

• High demand for milk calcium during early
  lactation calcium pulled from blood
• Cannot absorb enough calcium from gut or reorb
  from bone rapidly enough to keep up
• Severe hypocalcemia (low blood calcium) results
• Factors associated
• Parturition
• Onset of lactation
• Breed
• Age
• Diet

34
Hypocalcemiaat Parturition
Plasma calcium
PTH
1,25(OH)2D3
Absorption from GI tract
Absorption from kidney
Plasma calcium increased
Resorption from bone
35
Milk Fever

• Symptoms
• Listless
• Staggers or weaves when walks
• Lies down in characteristic pose
• head retraction
• Decreased plasma calcium

36
Milk Fever

• Treatment
• IV calcium solution
• Oral calcium gels
• Prevention options
• Dietary acidbase balance, not calcium level
• Alter dietary cation-anion balance
• Feed anion salts or adjust dietary potassium
• Increased calcium release from bones and
  increased calcium absorption from diet
• Mediated through parathyroid hormone

37
Phosphorus Sources

• Minerals
• Dicalcium phosphate
• Monocalcium phosphate
• Deflourinated rock phosphate
• Animal sources
• Meat and bone meal
• Fish meal
• Cereals
• Large portion of phosphorus unavailable for
  non-ruminants
• Phytic acid (poorly absorbed)

38
Phosphorus (P)

• Functions
• Component of bones/teeth
• 80 in bone (hydroxyapatite)
• 20 in soft tissue
• Membrane phospholipids, DNA, RNA
• Similar to calcium
• Vitally important in energy metabolism
• ATP and creatine phosphate
• Sugar phosphates
• Acid-base balance (HPO4)
• Regulation of metabolism
• Glucose-6-phosphate
• Phosphorylation activates or inactivates enzymes

39
Phosphorus (P)

• Absorption
• Both active and passive mechanisms
• High phosphorus limits calcium absorption
• Plant phosphorus often unavailable to animal
• Phytic acid
• Released by phytase (enzyme often supplemented)
• Blood levels controlled by vitamin D and
  parathyroid hormone

40
Phosphorus Deficiency

• Deficiency
• Symptoms similar to calcium deficiency
• Reduced growth or production rate
• Rickets or osteomalacia
• Pica (depraved appetite) chewing of wood
  fences, bones, soil
• Low fertility and poor milk production or growth

41
Phosphorous

• Impact on environment has scientists revisiting
  nutritional requirements
• Requirements are being lowered without any
  negative effects on reproduction or milk
  production
• Bioavailability could be improved if phytate
  phosphorus can be reduced
• Increasing availability would reduce dietary
  requirements and fecal excretion

42
Magnesium Sources

• Mineral sources
• MgCO3, MgCl2, MgO (mag-ox)
• MgSO4
• a.k.a. Epsom salts, milk of magnesia

43
Magnesium (Mg)

• Functions
• Bone formation
• 60 in bone
• Enzyme activation
• Carbohydrate, lipid metabolism
• 7 enzymes in glycolysis require magnesium as a
  cofactor
• Urea cycle
• Binds mRNA to ribosomes
• Associated with ATP metabolism
• ATPMg2 complex

44
Magnesium and Muscle Function

• Magnesium required for energy releasing enzyme
  activity in skeletal muscle
• ATP needed for detachment and calcium uptake
• Calcium is the link between excitation and
  contraction
• Lack of ATP to return calcium to storage results
  in tetany

45
Magnesium

• Deficiency
• Vasodilation
• Results in reduced blood pressure
• Hyperirritability, convulsions
• Anorexia, reduced weight gain
• Hyperemia
• Hypomagnesemic tetany (grass tetany)
• Early lactating cows on grass
• Poor nervous and muscular control
• Usually not an issue, adequate levels present in
  most diets

46
Magnesium Deficiency Grass Tetany

• Also called grass staggers, hypomagnesemia
• Low blood magnesium
• Symptoms
• Nervousness
• Tremors, twitching of face muscles
• Staggering gait or convulsions
• Etiology not completely understood

47
Grass Tetany

• Spring pastures, lush grasses
• Low magnesium content
• Some magnesium absorption in rumen
• Requires relatively low pH
• High potassium forages raise rumen pH and impedes
  Mg absorption
• Potassium alters acid-base balance (cation
  induces alkaline environment)
• Pasture contains organic acids that bind
  magnesium
• Solution
• Dust pasture with MgO
• Feed 111 magnesium oxideTM saltgrain
  starting 2 weeks before turning ruminants out on
  pasture

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Sodium and Chloride Sources

• Minerals
• Salt (iodized, 0.007 iodine added)
• Add at 0.250.50 of diet
• Free-choice salt blocks
• May be combined with other minerals
• Animal sources
• Meat and bone meal, meat meal
• Fish meals may have a (very) high salt content
• Cereal grains
• Low sodium and choride content

49
Sodium (Na) and Chloride (Cl)

• Functions
• Electrolytes
• Absorption of glucose and amino acids
• Transmission of nerve impulses
• Action potential
• Osmotic pressure balance
• 10 sodium and chloride intracellular, 90
  extracellular
• Sodium is main extracellular cation
• Maintained by Na/K ATPase
• Chloride is main extracellular anion
• HCl and chloride salts in gastric secretions

50
Sodium and Chloride

• Blood concentrations highly regulated
• Excess intake increased excretion
• Little danger of toxicity if water available
• NaCl added to diets to increase palatability
• Causes of deficiencies
• Lactation
• Sodium and chloride secreted in milk
• Rapid growth
• On a diet of cereals or forages
• High temperatures or hard work
• Sweat

51
Symptoms of Sodium and Chloride Deficiency

• Decreased osmotic pressure
• Leads to weakness
• Circulatory failure
• Metabolic alkalosis (decreased chloride) or
  acidosis (decreased sodium)
• Poor growth
• Reduced appetite and feed consumption
• Reduced carbohydrate and amino acid absorption
• Diminished HCl secretion from parietal cells
• Reduced bacterial defense and protein digestion
• Pica or salt craving
• Animals will seek out salt sources
• Soil, urine, sweat of other animals, etc.

52
Pica

• Animals do not necessarily seek out sources of
  the mineral that is deficient in diet just
  consume non-feed items
• Coprophagia (consumption of excrement)
• Geophagy (consumption of soil, clay, or chalk)
• Consumption of dust or sand in iron deficient
  patients.
• Vampirism (ingestion of blood)
• Hyalophagia (consumption of glass)
• Pagophagia (pathological consumption of ice)
• Self-cannibalism (rare condition where body parts
  may be consumed sometimes called Lesch-Nyhan
  syndrome)
• Trichophagia (consumption of hair or wool)
• Urophagia (consumption of urine)
• Xylophagia (consumption of wood)
• Cautopyreiophagia (consumption of burnt matches)

53
Sodium and Health

• High blood sodium is associated with high blood
  pressure and risk of heart disease
• However, high blood sodium rarely due to dietary
  excesses
• Genetics is primary factor, although other
  factors are involved
• 10-15 of adults are salt-sensitive and should
  limit salt intake

54
Potassium Sources

• Plants generally have a high potassium content
• Grains 0.30.8
• Vegetable proteins 1.02.5
• Alfalfa 2 or more
• Implications for dairy in developing anionic
  diets for preventing milk fever!!
• Animal products vary

55
Potassium

• Functions
• Third-most abundant mineral in the body
• 2/3 of whole-body potassium content in skin and
  muscles
• gt95 of potassium intracellular (major
  intracellular cation)
• Maintained by Na/K ATPase
• Regulation of osmotic and acid-base balance
• Transmission of nerve impulses
• Potassium is the major determinant of the resting
  membrane potential of all cells
• Cofactor for several reactions in carbohydrate
  metabolism

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Potassium Deficiency

• Rare
• Has to be induced
• Major salt in ruminant sweat
• Increases requirement in heat stress
• Reduced appetite and growth
• Other symptoms
• Tetany, nervous disorders
• Degeneration of organs
• Abnormal heart function

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Sulfur (S)

• Located in organic compounds
• Thiamin biotin methionine, cystine and
  cysteine
• Chondroitin sulfate matrix of cartilage
• Feathers, wool, etc.
• Wool contains about 4 sulfur
• Minimal involvement in acid-base balance
• Ideal NS ratio of 101 in ruminant diets
• Potential for toxicity

58
Trace Minerals
Pages 3639 in textbook
59
Trace Elements (Minerals)

• Need small amounts of these
• Found in plants and animals
• Content in plant foods depends on soil content
  (where plant was grown)
• They are difficult to quantify biochemically
• Bioavailability often influenced by other dietary
  factors (especially other minerals)

60
Iron Sources

• Plants
• Leafy, green materials (especially legumes)
• Seed coats
• Animal sources
• Meat and bone meal, meat meal, blood cells
• Milk is a poor source of iron

61
Iron

• Iron exists in two oxidation states
• Ferrous iron (2 state)
• Ferric iron (3 state)
• High affinity for oxygen, nitrogen and sulfur

62
Iron Functions

• Hemoglobin and myoglobin
• Contain four and two iron molecules, respectively
• 50 of iron in body is hemoglobin, 20 is
  myoglobin
• Functions in oxygen transport
• Only ferrous (2) iron can reversibly bind oxygen
• Redox processes
• Fe2, Fe3
• Electron transfer chain
• Component of many enzymes
• Immune function
• Brain function
• Iron deficiency/toxicity thought to slow mental
  development in humans

63
Iron Absorption

• Primary regulator of iron homeostasis
• Absorption varies between 1-50
• If body needs more iron, it increases amount of
  transferrin an iron-carrying protein (binds to
  ferric (3) form of iron)
• Iron can also be stored in another protein called
  ferritin

64
Iron Absorption

• Iron from animal sources (heme iron) much better
  absorbed than that from plant sources (non-heme
  iron)
• Absorption of non-heme iron (plant sources)
  increased by
• Vitamin C
• Meat in diet (MFP factor)
• Citric acid and lactic acid from foods
• HCl in the stomach
• Sugars
• Absorption is decreased by
• Phytates and fibers (grain products)
• Polyphenols (tea, coffee)
• Oxalates
• Calcium and phosphorus in milk
• Tannic acid
• Other minerals (calcium, zinc)

65
Iron Deficiency

• Most common mineral deficiency worldwide
• Anything that creates blood loss creates
  deficiency
• Menstruation in primates
• Gastrointestinal parasites or pathogens
• Newborn and young animals easily deficient
• (piglets, veal calves, lambs)
• Limited stores at birth (poor placental transfer)
• Milk levels are very low, no soil contact (soil
  is iron source)
• Rapid growth

66
Iron Deficiency

• Sows milk deficient in iron
• Baby pigs injected with iron dextran
• Symptoms
• Anemia, poor growth
• Pale skin, transparent ears
• Thumps
• Labored breathing
• Enlarged heart
• Diarrhea
• Secondary symptom

67
Iron Deficiency Anemia

• Symptoms
• Reduced number of red blood cells
• Turnover of RBCs takes 6090 days
• ? hemoglobin concentration of blood
• ? red blood cell size
• Microcytic, hypochromic anemia
• Cognitive problems, poor growth, decreased
  exercise tolerance
• Iron deficiency and pica (geophagia)
• Pica craving for non-food substances (clay,
  paste, etc.)
• Reduced resistance to infection pale and itching
  skin decreased cold tolerance

68
Iron Toxicity

• Iron overload known as hemochromotosis is caused
  by genetic disorder which increases iron
  absorption
• Hemosiderosis condition caused by long term
  over-consumption of iron resulting in large
  deposits of iron storage protein (hemosiderin) in
  liver and other tissues

69
Copper (Cu) Trace Mineral

• Functions
• Red blood cell formation
• Required for iron absorption from small intestine
• Required for transfer of iron from cells to
• plasma oxidation of iron from ferrous to
• ferric state
• Integral component of many enzymes (e.g.,
  cytochrome oxidase)
• Bone development
• Structural integrity of collagen and elastin
• Hair and wool pigmentation
• Keratin formation in wool and hair
• Stored in most tissues, especially liver

70
Copper - Deficiency

• Vitamin C interferes with absorption
• Microcytic anemia
• Cardiac and vascular disorders
• Bone disorders (spontaneous fractures)
• Depigmentation of hair or wool
• Black sheep are sometimes kept as indicators of
  marginal Cu deficiency
• Loss of wool crimp (steely wool)
• Central nervous lesions with lack of muscular
  coordination

71
Induced Copper Deficiency

• Caused by relatively high levels of molybdenum
  and/or sulfur
• Site of interaction is in the rumen
• Formation of insoluble copper salts including
  sulfides and thiomolybdates
• Net effect is decreased copper absorption

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Induced Copper Toxicity

• Occurs with normal dietary levels of copper and
  low levels of molybdenum and sulfur
• Copper accumulates in liver
• Sheep are more susceptible than cattle or pigs

74
Zinc (Zn) Trace Mineral

• Functions
• Component of metalloenzymes
• Includes DNA and RNA synthases
• Synthesis of skin keratin and collagen

75
Zinc (Zn)

• Deficiency
• Impaired reproduction, delayed puberty
• Lesions of skin, disorders of hair, feathers,
  etc.
• Parakeratosis
• Growth retardation
• Low insulin and high ammonia in blood
• Low white blood cell count susceptibility to
  infections
• Anorexia
• Night blindness

76
Zinc (Zn)

• Toxicity
• Relatively non-toxic in excess
• Anemia
• Higher LDL and lower HDL levels
• High white blood cell count
• Renal failure

77
Manganese (Mn)

• Functions
• Cofactor for enzyme systems
• Synthesis of chondroitin sulfate in bone matrix
• Deficiency
• Defective bone formation
• Perosis slipped tendon
• Poultry
• Diet is adequate for most species

78
Cobalt (Co) Trace Mineral

• Functions
• Required only as a component of vitamin B12
• Ruminant animals require for microbes
• Vitamin B12 is and essential cofactor for enzymes
  involved in
• Propionate metabolism
• methylmalonyl CoA to succinyl CoA
• DNA synthesis
• Bacterial synthesis of methionine
• Deficiency
• Mimics B12 deficiency in ruminants
• Anemia
• Emaciation

79
Cobalt

• In 1930s, a wasting disease was first associated
  with cobalt deficiency in plants and soils
• Vitamin B12 was found to contain cobalt

80
Cobalt and Vitamin B12

• Injection of cobalt-deficient sheep and cattle
  with vitamin B12 was as effective as feeding
  cobalt in curing the disease
• Injection of cobalt has no effect
• Microbial synthesis of vitamin B12 was the key!

81
Cobalt Deficient Areas of the US
82
Chromium

• Involved in carbohydrate, lipid, and protein
  metabolism
• Component of glucose tolerance factor when
  chelated with niacin and several amino acids
• Increased insulin binding to receptor
• Increased numbers of insulin receptors
• Alleviates gestational diabetes in some cases
• Established as an essential mineral in swine
• However, requirement is not known
• In the ppb range
• Hard to show a deficiency

83
Dietary Sources of Iodine

• Seafoods
• Milk/dairy products
• Iodized salt

84
Iodine

• Iodine from foods is converted to iodide (ionic
  form) in the GI tract
• Function
• Essential component of thyroid hormones
• Important for regulation of body temperature,
  basal metabolic rate, reproduction and growth
• Regulation in body
• Almost all is absorbed
• Excess removed in urine

85
Iodine Deficiency

• The hypothalamus controls the production of
  thyroid hormones
• Monitors thyroid stimulating hormone produced by
  the pituitary
• When iodine deficiency occurs, thyroid hormone
  production decreases
• Body responds to this by secreting more thyroid
  stimulating hormone
• Eventually leads to the enlargement of the
  thyroid gland - simple goiter

86
Iodine Deficiency

• Decreased growth
• Goiter (less severe)
• Enlarged thyroid gland due to bodys attempt to
  increase thyroid hormone production
• Cretinism (more severe)
• Severe iodine deficiency during pregnancy?serious
  problems in fetal development
• Increased incidence of stillbirths abortions
• Stunted growth, deaf, mute, mentally retarded

87
Iodine Deficiency

• Certain foods from the cabbage family contain
  antithyroid substances, called goitrogens
• Over-consumption of these foods also may cause
  hypothyroidism
• Excessive intakes of iodine also may cause the
  enlargement of the thyroid gland

88
Functions of Selenium

• Component of glutathione peroxidase
• Free radical scavenger that catalyzes removal of
  hydrogen peroxide from cell membranes
• Interrelated with vitamin E
• Can partially spare vitamin E (makes up for
  slight deficiencies)
• Improves killing ability of neutrophils
• Reduces the prevalence and severity of mastitis
• Conversion of T4 (thyroxine) to T3 (4x more
  active)

GSH H2O2 GSSG H2O
GSH reduced glutathione GSSG oxidized
glutathione
89
Selenium - Deficiencies

• Keshan disease is characterized by heart
  enlargement replacing the muscle tissue with
  fibrous tissues
• White muscle disease in lambs and calves
• Skeletal and cardiac myopathies
• Exudative diathesis (hemorrhagic disease) in
  chicks
• Liver necrosis
• Concentration in feeds is soil dependent
• Toxicity/deficiency related to geographic area

90
White Muscle Disease

• Results from a deficiency of selenium or vitamin
  E
• Characterized by white streaks in striated muscle
• Prevented by injection of vitamin E and selenium

91
Selenium

• Toxicity causes blind staggers or alkali disease
• Range between minimum requirement and maximum
  tolerable level is narrow
• Supplementation must be done with care
• FDA regulations allow only two forms of inorganic
  selenium (sodium selenite and sodium selenate) to
  be used
• 0.3 mg of supplemental selenium/kg of dietary DM
  is maximum

92
Selenium Content of Soils
93
Molybdenum (Mo) Trace Mineral

• Sources
• Legumes, cereals, organ meats
• Functions
• Component of many metalloenzymes
• Component of xanthine oxidase
• Nucleic acid (purine) metabolism
• Deficiency
• Toxicity more common than deficiency
• Induces copper deficiency

94
Sources of Fluoride

• Water
• Natural
• Fluoridated
• The practice of fluoridation is questioned now
  because of risk of fluorosis (mottling) of teeth

95
Fluoride

• 99 of ingested fluoride is found in bones and
  teeth
• Function
• To promote mineralization of calcium and
  phosphate
• Inhibits bacterial growth in mouth?decreases
  cavity formation
• More toxin than dietary essential for animals
• Not commonly supplemented
• Cumulative poison