lecture 14 - nutritive value of feeds - minerals

are minerals a micro or macro nutrient

micronutrient

what are the forms of minerals in feed

in complexes with other minerals (like bone); as components of enzymes, hemoglobin, thyroxine

what are the functions of minerals

structural and regulatory

define a mineral

naturally occurring inorganic element

not carbon based or derived from living organisms

what is the total mineral content of plants or animals called

ash

define a macromineral

normally present at ↑ levels in body or have a physiological re for a ↑ level

what are some macrominerals

Ca

Cl

Mg

P

K

Na

K

S

what percentage of the diet do macrominerals make up

> 0.01% of total diet

calcium makes up what % of the total body mineral

50%

phosphorus makes up what % of total body mineral

25%

define trace minerals

normally present at ↓ levels in body or have a ↓ physiological req

what are some trace minerals

chromium (Co)

Cu

Fe

I

F

Mn

molybdenum (Mo)

Se

Zn

what percentage of the diet do trace minerals make up

< 0.01% of total diet

what are some structural functions of minerals

primary components in bones and teeth

integral part of blood clotting rxn

constituents of organic compounds like proteins/lipids

what percent of total body Ca/P are in bones and teeth

~99% of Ca and ~80% of P

what are some examples of minerals as part of proteins or lipids

sulfur-containing aas, phospholipids

what are some sulfur containing aas

methionine, cysteine, taurine

what are some regulatory functions of minerals

activators or components of enzyme systems

maintence of osmotic pressure

maintain BP

regulate muscle contractions/nerve signaling

when looking at diet, what minerals are looked at the most

Ca and P

why is the Ca:P ratio important

P competes with Ca for absorption in the gut

excess Ca can ↓ P absorption

how should the Ca:P ratio be balanced

less than 1:1 or more P than Ca

what is vitamin D important for

adequate absorption of utilization of Ca and P

is Ca or P needed more

Ca

what is the Ca:P ratio of pigs, poultry, horses, dogs, and cats

1:1 to 2:1

what is the Ca:P ratio of dairy cattle

1.5:1 to 2:1

what is the Ca:P ratio of laying hens

6:1

~95% of eggshells are

calcium carbonate

how much Ca is secreted in milk per day by dairy cattle

~50g

does Ca req ↑ with onset of latation, growth, or pregnancy

yes

how narrowly must trace minerals be monitored

range between safe supplementation and toxic levels are narrow

what must trace mineral supplements take into consideration

supply from base diet and contributions from other additives with trace elements

species specific ranges

some are antagonists to absorption of other trace minerals

where do surplus trace minerals accumulate

liver

what are some atagonisms of Cu

Zn interferes with Cu absorption

Fe interferes with absorption and Cu release from liver

Mo and sulfate form insoluble complex with Cu in GI tract making it unavailable

how does Cu poisoning occur

when accumulated Cu is released from liver

why are sheep highly susceptible to Cu poisoning

they are very efficient at absorbing Cu from both small and large intestine

where do most animals absorb Cu

in small intestine only

what are generally good sources of most minerals

forage plants

what is the most Ca rich forage

alfalfa

what is alfalfa good for

gut buffering in animals prone to acidosis or ulcers

meat and bone meal are rich in

Ca and P

cereal grains are a good source of

P

what is the storage form of P in most plants

phytic acid

what percent of total P in plant sources are in phytic acid

~50-80%

is P in phytic acid available to non-ruminants and poultry

no

what is phytase

an enzyme which breaks down phytic acid and releases its P atoms

can phytic acid be broken down by microbes

yes

what animals are often supplemented with phytase

swine, poultry, and dogs on plant based diets

plants grown on soils deficient in a mineral are likely to be...

deficient in that mineral

what factors affect mineral content geographically speaking

soil composition

climate

plant species

agronomic practices

what should mineral supplements be used for

to balance diets based on content and availability of mineral in main components of diet

how can Ca and P be supplemented

limestone → Ca

dicalcium phosphate → Ca and P

oyster shell → Ca

monosodium phosphate → Na and Ca

meat and bone meal → Ca and P

what is the most common salt added to the diet

NaCl

what are some types of salt that can be added

plain or iodized salt

trace mineralized like Co, Mn, Fe, Zn, and Cu

why is salt supplementation added for performance animals like horses

to replenish losses through sweat

what are used as carriers in trace mineral premixes

inert products or feedstuffs like soy flour, protein meals, rice hulls

what are some forms of available trace minerals

hydroxy form

aa chelate

sulphate form

describe the hydroxy form of trace mineral forms

more microbe resistant so preferred in ruminants to ↑ intestinal absorption

describe the aa chelate form of trace mineral forms

can ↑ absorption in animals where microbial degradation is not a concern

describe the sulphate form of trace mineral forms

generally lowest absorption

digestion and absorption of minerals is affected by

sources and chemical form

other diet constituents

life stage

species

demand vs supply

do young or older animals absorb Ca and P more efficiently

young animals

trace mineral are usually expressed in

mg/kg which is equivalent to ppm