lecture quiz 6: minerals Flashcards
1
Q
coprophagy
A
hind-gut fermenters (horses & rodents) eat feces for the microbial proteins produced in the cecum/colon
- common in rodent species (esp rats & rabbits)
- rabbits recycle ~40% of feces
- rodents depend on feces for EAA
- horses get enough EAA from normal diet (corprophagy is not main source)
2
Q
ash
A
total mineral content of plants/animals
3
Q
mineral makeup in the body
A
- make up 3-5% of animal body dry weight
- Ca accounts for ~50% of total body minerals
- P ≈ 25%
- all other minerals ≈25%
4
Q
mineral classifications
A
- major (macro) minerals = normally present at greater levels in body or needed in relatively large amounts in diet
- trace (micro) minerals = normally present at low levels in body or needed in small amounts in diet
5
Q
essential minerals
A
major (macro) minerals & trace (micro) minerals
- all minerals are essential → body cannot make
6
Q
major (macro) minerals
A
- Ca
- P
- Na
- Cl
- Mg
- K
- S
7
Q
trace (micro) minerals
A
- Co
- Cu
- F
- I
- Fe
- Mn
- Mo
- Se
- Zn
8
Q
mineral fxns
A
- structural (e.g. Ca & P = primary component of bones)
- metabolism as activators or components of enzymes (cofactors) ➞ trace minerals
- maintenance of osmotic pressure & regulate exchange of water & solutes (Na, Cl, K)
- constituents of organic compounds (e.g. P major component of phospholipid cell membrane & AA containing S: methionine & cysteine)
9
Q
importance of Ca in production
A
- bone & teeth formation
- milk production
- egg shell formation
10
Q
importance of P in production
A
- bone & teeth formation
- metabolism & energy (phosphorylation)
- phospholipids, nucleic acids, & other important biological mol
11
Q
most important minerals & their ratio to consider in diet formulation
A
Ca & P in a ratio of ≥1:1
- never lower in Ca
- growing animals & dairy: 1.2-2:1
- laying hens: 6:1 (egg shell requires Ca)
- similar absorption of Ca & P ∴ they compete so ratio is important
12
Q
natural sources of minerals
A
- inorganic ➞ turn to ash when burned
- can come from water
- forages = good sources of most minerals
- if the soil has minerals the plant will too
- grains = fair source of P but low in other minerals
- lots of P in grains but tied up in phytate (phytic acid)
- non-ruminants cannot digest phytate (ruminants can)
- too much P messes up Ca:P ratio
- commercial phytase is often supplemented to swine & poultry diets to break down phytate & improve dietary P utilization
13
Q
mineral content of forages
A
- some soils are inherently deficient in certain trace minerals due to soil geology (e.g. I & Se)
- plants grown from soils deficient in a mineral are also likely to be deficient
- soil composition varies region to region
14
Q
mineral supplements
A
Ca & P → in greatest abundance & most commonly supplemented
- common sources:
- oyster shell (Ca only)
- ground limestone (Ca only)
- dicalcium phosphate (Ca:P 2:1)
- mono-sodium phosphate (P only)
salt (NaCl)
- iodized or plain
- trace mineralized = contains compounds of Co, Mn, Fe, Zn, Cu (must be careful b/c range of requirements to toxicity very close)
- fed as loose (0.25-5% of diet) or block (animals choose to ingest or not)
- salt added as a way to control trace mineral intake
- animals know when they’ve had enough salt so stop eating
- nutritionists can use that to calculate how much of each trace mineral to add
trace mineral premix
- various inert products or feedstuffs are used as carriers
- e.g. soy flour, protein meals, rice hulls, etc.
- adds bulk to ensure uniform mixing
15
Q
mineral units of measurement
A
- amount required per animal daily (g, mg, mcg) → major minerals (Ca & P)
- e.g. dairy cows producing X amount of milk require Y amount per day
- more common for larger animals
- percent or amount per weight unit of diet
- poultry & swine
1. major minerals usually %
2. trace minerals usually mg/kg (=ppm)
- poultry & swine
