Lecture 9- Minerals Flashcards
What are the functions of minerals in metabolism?
- Some participate with enzymes in metabolic processes
- Some have structural functions (Ca, P in bone; S in keratin)
• Acid-base and water balance (Na, K, Cl)
- Unique functions
- e.g., Fe in heme, Co in B12, and I in thyroid hormones
What is the division/classification of minerals?
- macro or major minerals
- micro or trace minerals
What are macro or major minerals?
- Sodium, potassium, magnesium, calcium, phosphorus, sulfur, chloride
- Present in body tissues at concentrations >50 mg/kg (50 ppm)
What are micro or trace minerals?
- Chromium, manganese, iron, iodine, cobalt, molybdenum, copper, zinc, fluoride, iodine, selenium, silicon, tin, arsenic, nickel…
- Present in body tissues at concentrations <50 mg/kg (50 ppm)
What are the nutritionally important minerals?
What are the minerals in food?
- Found in all food groups.
- More reliably found in animal products.
- Often other substances in foods decrease absorption (bioavailability) of minerals • Oxalate, found in spinach, prevents absorption of most calcium in spinach.
- Phytate, form of phosphorous in most plants makes it poorly available
• Calcium and phosphorus are the most plentiful nutrients in the mammalian body
Dominant minerals in bone and teeth (skeleton stores minerals that can be used in times of
deficiency e.g. lactation)
99% of Ca is in bone; 80% P is in bone
The 20% of P in ‘other’ locations is important
• ATP/ADP, cell wall, RNA & DNA, acid base balance etc.
What is the iron requirement for men and women?
-women need much more iron
What are the factors affecting mineral requirements?
- Physiological state/level of production • Interactions with other minerals
- Tissue storage
- Form fed
• inorganic vs organic forms
• Na selenite (inorganic) vs Na selenate (inorganic) (Absorbed by passive diffusion and little retained in tissue reserves
Large amounts excreted )
vs selenomethionine (organic =Actively transported through intestinal membranes during absorption & incorporated into tissue proteins )
What are the mineral interactions?
-pretty much everything interacts with everything!
What are the issues with deficiencies and excesses of minerals?
- Most minerals have an optimal range • Below leads to deficiency symptoms
- Above leads to toxicity symptoms
- Mineral content of soils dictates mineral status of plants (i.e., feeds)
- May take many months to develop, depends on what it is
- Time impacted by body stores
How can Copper be toxic?
- Copper is a cumulative poison
- Animals are unable to excrete it properly so small amounts build up
- Particularly in liver tissue
- Species specific – pigs are tolerant but sheep susceptible
-copper pipes transport water= if old, copper leaks into the water supply and this build up in the animals over time
Whata are some characteristics of Calcium (macro-mineral)?
- Most abundant mineral in animal tissues
- Lots of functions
- Bonestructure
- Nerve function
- Bloodclotting
- Musclecontraction
• Cellular metabolism
What are some of the food sources of Calcium?
- Milk and dairy products
- High amounts
- High bioavailability (fortified with vitamin D)
- Green leafy vegetables
- Poor absorption
- Fish with bones?
- Fortified juice/cereal
What are the symptoms of calcium deficiency in young and in old animals?
• Young animals:
- Rickets (misshapen bones)
- Enlarged joints
- Lameness and stiffness
• Old animals = Milk fever
- Occurs in lactating cattle, goats & sheep
- 72 hours after calving
What is the incidence of milk fever and what does it depend on?
- Incidence of milk fever
- increase in Ca demands of lactation leads to reduced blood pH
- More frequently in high-producing cows
- Increases with cows’ age
- More common in Jersey than other breeds
• Repeats common in cows with a previous history
What are the symptoms of milk fever?
• Symptoms of milk fever
- Muscular spasms, loss of appetite,
- low blood calcium (3-7) normal is 10 mg/100 ml
- Depression, dull staring eyes, dilated pupils
- Extreme cases: paralysis leading to unconsciousness and sometimes even death
What are the treatment and prevention of milk fever?
- Intravenous injection of calcium gluconate
- Provide adequate Ca and P during the dry period
• Transition period feeding important
What are Ca and P needed for and what should the dietary ratio?
- Both Ca and P are required for bone formation and other non- skeletal functions
- Dietary ratio of 1:1 to 2:1 is good for most animals (exception is laying hen, 13:1; Ca:non phytate phosphorus)