minerals Flashcards
what are the two mineral classes?
Macro-minerals
Micro-minerals
what percent in diet is a macro-mineral?
> 0.01% (100mg/kg) in diet
what percent in diet is a micro-mineral?
< 0.01% (100mg/kg) in diet
Name the seven Macro-minerals
Calcium Phosphorus Sodium Chlorine Potassium Magnesium Sulfur
What are the 14 micro-minerals?
Iron Manganese Copper Selenium Molybdenum Fluorine Iodine Silicon Cobalt Chromium Zinc vanadium nickel arsenic
What is the elemental compositions of most species in regards to one another? What is the exception and why?
Most species have a relatively uniform elemental composition, except in young animals, which have lower Ca and P.
Dietary requirement is highly correlated with what?
body level
Concentration in animal tissues of Calcium
15 g/kg BW
Concentration in animal tissues of phosphorus
10 g/kg BW
Concentration in animal tissues of potassium
2 g/kg BW
Concentration in animal tissues of sodium
1.6 g/kg BW
Concentration in animal tissues of chlorine
1.1 g/kg BW
Concentration in animal tissues of sulfur
1.5 g/kg BW
Concentration in animal tissues of magnesium
0.4 g/kg BW
What are the structural functions of minerals?
components of bone and tissues, eg. Ca, P, and S
what are the electrochemical functions of minerals?
acid-base balance, osmotic control, H2O balance, eg. K, Na, and Cl
What are the catalytic functions of minerals?
component of hormones and enzymes, eg. S, Mg, Fe, Zn, Cu, I
Which mineral is the most abundant mineral element in the body?
Calcium
What percent of body weight is calcium in humans and animals?
1-2% of body weight
avg. human is 1.2 kg of Ca (90kg man)
avg. dairy cow is 9.4 kg Ca (600 kg cow)
Dietary sources of calcium for humans
milk and dairy products (75% of total)
legume seeds
good dietary sources of calcium in animals
- Legume roughage - 1-2% of DM
- animal by-products (meat by-products): 5-12% of DM
- fish meal: 3-8% DM
- ground limestone and dicalcium phosphate (dairy cows and laying hen diets) 30-40% of DiCal-P
Poor dietary sources of calcium in animals
cereal grains and roots - < 0.2% of DM
Functions of Calcium
Bone and teeth: 46% minerals by weight
egg shells: almost pure CaCO3
Muscle contraction and nerve impulses
Acid-base balance: cation-anion balance of diets
blood clotting mechanism
What mineral salts are in bones/teeth?
hydroxyapatite crystals: 36% Ca, 18% P, and 1% Mg
3 Cac (PO4)2 x Ca(OH)2 Ca:P ratio = 1.3 to 2:1
what is the Body distribution of Calcium
99% in bone and teeth
1% in blood, body fluids, and within cells
what is the Blood distribution of calcium
Plasma Ca(2+) levels
mammals: 2.25-2.75 mM (90-110 mg/liter) poultry: 7.5 - 10 mM (300-400 mg/liter)
Where is calcium absorbed?
in the duodenum and jejunum
how is calcium excreted?
urine (20-30%)
feces (70-80%)
Perspiration (minor)
what ion is necessary at all steps in Fibrin formation?
Calcium (2+)
What are the ten factors influencing calcium absorption?
- the sources of calcium
- dietary acidity
- sugars
- vitamins
- estrogen
- age
- excess phosphorus
- phytate
- Diet Fat content
- Oxalates
How do the sources of calcium affect absorption?
Cereals: low in Ca, plus contain phylates which chelate Ca and reduces absorption in monogastrics
Bone meal: Ca 100% available
Alfalfa: Ca low in availability (16-88%)
How does diet acidity affect calcium absorption?
increases absorption by increasing solubility of Ca-chelates
How do sugars affect Ca absorption?
Lactose- Increases Ca passive absorption in suckling animals
How do vitamins affect Ca absorption?
increase Ca absorption via Calbindin
How does estrogen affect Ca absorption
increases it
Post-menapausal women are at risk for what disease and why?
at risk for osteoperosis
have low estrogen levels
How does age affect Ca absorption?
decreases with age
how does excess phosphorus affect Ca absorption?
causes it to decrease
How do phytates affect Ca absorption?
chelates and binds Ca (and P)
How do oxalates affect Ca absorption?
forms Ca-Oxalate (insoluble); reduces absorption
How does diet fat content affect Ca absorption?
excess dietary fat reduces Ca absorption due to fatty acid Ca-soap formations
What is phytic acid?
the plants’ storage form of phosphorus
where does chelation occur? On what?
Occurs in plants and in digestive tract
chelates all cations (Mg, Zn, Cu, Ca, Mn, Fe, and K)
High Ca-Phytate prevents release of what by What?
Phosphorus by animal phytases
If there is low Ca, what gland is activated?
parathyroid gland
What hormone does the parathyroid gland release?
PTH
what does PTH do?
- Induces Kidney
- 1-alpha hydroxylase
- Ca reabsorption at kidney
- Phosphate exretion at kidney
Vitamin D is released in what form?
1, 25 (OH)2D
What does 1, 25(OH)2D do?
- promotes Ca reabsorption at kidney
- Promotes Ca resorption from bone
- promotes Ca and PO4 absorption from the intestinal tract
If there is high Ca, what gland is activated?
Thyroid gland
what does the thyroid gland release?
calcitonin
what does calcitonin do?
suppresses PTH release and action
this suppresses 1, 25 (OH)2D
inhibits Ca reabsorption at kidney
what does calcitonin do?
suppresses resorption of bone
What are the net effects of Calcium regulation?
- maintain normal plasma Calcium concentration
2. keep Ca:P ratio in plasma constant
How much calcium does a human need? (old and avg.)
old: 1200mg/day
avg: 800 mg/day
Animal calcium daily intake?
chick- 1% (rapid bone growth) laying hen- 3.5% (due to egg shell formation) swine- 0.8% calves, lambs, foals- 0.5% dairy cow- 0.4%
When does Rickets occur?
Mostly in young growing animals
What causes Rickets?
- deficiency of Ca, P, or Vit D (or all)
- Imbalanced dietary Ca:P outside of the 2.5:1 ratio
- Parathyroid hypertrophy: increases PTH (i.e. enlarged gland)
What is the mechanism of Rickets?
Continued growth of the collagen and organic matrix BUT no or insufficient mineralization (hydroxyapatite crystals and ossification) for support
What is the result of having Rickets?
- soft, light bone
- muscles continue to grow, increasing the weight on soft bone and causing the bone to bend