Micronutrients Flashcards
Minerals are
Minerals are micronutrients
Only required in small quantities in the diet
Usually <5%
Not a significant source of energy
Macrominerals are
Requirements are often expressed as % of the diet
* All have some structural role
* Includes Ca, P, K, Na, Mg
Microminerals are
- Requirements are often expressed as ppm or mg/kg
- Many are co-enzymes
- Despite being present in small amounts, are essential to function
- Includes Fe, Zn, Mn, Cu, I, Se
Potassium role
Maintains cell shape
Major role in cardiac function
Nerve conduction, muscle contraction
Majority of potassium in body found in cells
Sources of potassium
Widely distributed
Leafy plants are rich sources
Particularly roughages-grasses, alfalfa
Grains may be inadequate
Supplementation of potassium
Rarely a nutritional problem in herbivores
May need to be supplemented in pet foods
Potassium salt
When can you see potassium deficiencies
Problem in sick animals that are off feed
Muscle weakness, cardiac rhythm disturbances, pica
Diarrhea in small animals
High potassium losses
Excessive acidification of urine
Some heart or kidney disease demand modification of food-supplied amounts
Role of sodium
Contributor to osmotic pressure of extracellular fluid
Controls blood volume
Major role in cell’s energy metabolism
Sources of sodium
Sodium chloride (NaCl, salt) of mineral or marine origin
Fish, eggs, poultry by- product meal and soy isolates
Supplementation of sodium
Only mineral for which there is a clearly defined appetite
Added directly to food or offered as part of mineral block
Increases palatability
Sodium deficiency animal behaviour and signs
In cases of deficiency, animals typically seek out salt
After months of deficiency
◦ Reduced feed intake, growth / lactation
◦ PU/PD
Sodium toxicity can be caused by and looks like
More than 2% salt in diet can be toxic
Toxicity also affected by water availability
Signs
◦ Diarrhea, PU / PD
◦ Decreased production
When does sodium toxicity happen
Salt toxicity occurs with excess salt and/or limited/intermittent water
Pigs partially susceptible
See signs if normal diet sodium
No water
Hypernatremia and CNS disease
Wandering
Blindness, deafness
Head-pressing, dog-sitting
Takes at least 2 days to develop
Chlorine is
Closely associated with sodium in maintaining osmotic pressure, regulating acid-base equilibrium and cell metabolism
Usually present in sufficient amounts if sodium requirement being met
Role of calcium
Important in formation of bones (99% of body’s calcium is retained in bones)
Muscle function and nerve transmission
Blood clotting
Source of calcium
Bone meals
Milk
Grains and meat are poor sources
Supplementation of calcium
Calcium supplementation for high-risk individuals
Vitamin D important in regulating absorption
Balance of Ca is important
Acute deficiency (hypocalcemia) causes and looks like
Usually seen in late pregnancy/early lactation
Late pregnancy, particularly sheep and small dogs with lots of foetuses
Early or rapidly rising lactation
Dairy cows after parturition
Small dogs with lots of pups
About 2-3 weeks post whelping
In all cases, going off feed also predisposes
What does the increase need for calcium do
Increased demand for calcium overcome the ability to maintain homeostasis
Body stores (bones) are adequate
Low plasma ionized Ca++
Calcium removal exceeds replacement from diet and bone
Especially likely when sudden increase in demand (e.g. onset of lactation) and reduced intake (bad weather)
Mobilization from bone cannot keep up
Signs of hypocalcemia
In ruminants hypocalcemia effects all types of muscle
Weakness and recumbency
In horses and dogs signs of increased nerve irritability dominate
Tetany and muscle stiffness (dogs)
Restlessness, aggression, whining (dogs)
Thumps (horse)
Prevention of hypocalcemia in cattle
Promote mobilization of calcium at calving
Avoid high Ca concentrations in prepartum ration
Alfalfa high in Ca
Grass hays, cereal silages, corn silages better
Anionic diets (dietary cation-anion balanced feeding systems-DCAB)
Acidic diets promote acidic-conditions
Increase effectiveness of Ca regulating hormones
Promotes calcium mobilization from cows bones
Ensure diet adequate in magnesium
Important in PTH secretion and activity
Activation of vitamin D
Prevention of hypocalcemia
High oral doses of Ca drive additional Ca absorption
Ca pastes given to cattle around the time of parturition
Ca supplements to high risk bitches
Chronic calcium deficiency causes
Bone stores reduced
Mild hypocalcemia, not usually severe enough to cause signs
osteomalacia/rickets
Most common causes are dietary insufficiencies of phosphorous or vitamin D
In growing animals, imbalance Ca/P
As bones mature at different rates, it is possible to see rickets and osteomalacia in the same animal
Calcium toxicity looks like
Some surplus Ca is excreted in urine
Especially in horses- gives white colour to urine
Excessive dietary Ca predisposes to urinary tones/crystals in horse and cats (Ca oxalate type)
As well as conditions that predispose to hypocalcemia
Calcium protects against struvite crystals in ruminants (MgNH4PO4)
Excess calcium in growing puppies can cause
Excess Ca in growing puppies can cause skeletal abnormalities
Absorb Ca passively through intestine
Vitamin D only plays role in regulation after about 10 months
Concern for breeders/owners supplementing large breed diets with Ca
Phosphorus role
Intricate relationship with calcium, important in healthy bones (86% of body’s phosphorus is retained in bones)
Cell membranes
Energy dispersement
DNA, RNA
Source of phosporus
Oilseeds
Grains
Wheat bran
Meat
Low concentrations in grasses and legumes
Supplementation of phosphorus
Balance with Ca is important
Chronic phosphorus deficiency caused by
Reduced food intake, production, weight loss
Post parturient hemoglobinuria in adult cattle
Skeletal issues with low phosphorus
Rickets/osteomalacia
Spontaneous features
Toxicity of phosphorus looks like
High levels predispose to urolithiasis
Especially if dietary Ca is low
May suppress absorption of calcium
Bone loss
The ratio of Ca:P is important for healthy growth
Between 1:1 and 1:3
Role of magnesium
Component of bone and intracellular fluids
Important in PTH secretion and activity (Ca homeostasis)
Nervous conduction and muscle contraction
Contributes to body’s general energy metabolism
magnesium deficiency can look like
Acute onset often related to hypocalcemia
Magnesium is required to PTH to work
Sudden onset of nervous signs
Tetany, convulsions, sudden death
Chronic signs are wasting/poor growth/anorexia
Toxicity of magnesium is cased by and looks like
Excess magnesium can predispose to uroliths
Struvite (Magnesium Ammonium Phosphate)
However, magnesium can inhibit the formation of other uroliths
Calcium oxalate
Urolith prevention diets were often restricted in Mg to slow down struvite formation, esp in cats
Has been shown that pH moderation is more effective prevention method
Meeting minimum Mg levels is considered safe
Source of magnesium
Bone
Oilseed
Unrefined grain and fiber
Supplementation of magnesium
Absorption affected by dietary levels of phosphorus, calcium, potassium, fat and protein
Certain drugs can increase renal wasting of Mg
Role of iron
Constituent of hemoglobin (pigment that transports oxygen in RBC) and myoglobin (does same job in muscles)
Enzymatic functions
Most abundant trace mineral (and vital for body function)
Source of iron
Liver
Meat and fish
Green vegetables
Mineral salts
Supplementation of iron
Rarely deficient in diet
Can be a problem in animals with blood loss anemia
Supplementation can help patient to regenerate and recover from anemia
Role of copper
Most of copper stored in liver
Facilitates intestinal absorption of iron
Promotes cellular oxidation
Synthesis of collagen in tendons and myelin in nervous system
Source of copper
Meat (lamb, port, duck)
Proteinaceous grains (peas, lentils, soy)
Supplementation of copper
Most economically important deficiency of cattle
Mineral salts
Copper deficiency is caused by what major factors
Deficiency is the result of the interplay of 3 major factors
Copper
Molybdenum
Sulfate
High dietary molybdenum and sulfate is caused by what
Prevent absorption of copper
Increase excretion of copper
High sulfates are a major problem with come Prairie water sources
Copper deficiency in young growing animals causes
Mainly cattle
Poor growth
Epiphysitis
Chronic mild lameness
Lightening of hair coat
Mild anaemia
Diarrhea if high molybdenum
Copper deficiency in adults causes
Failure to get pregnant (anestrus)
Downer cows in cattle
Supplement with copper salts is used for
Ideally add trace minerals directly to diet
Can feed to cattle as a trace mineralized salt block
Variable and sometime inadequate copper content
Windsor trace mineralized salt: 330 ppm Copper
Can have a high copper ™ salt to help
Windsor ™ HI-Boot high copper zinc trace mineralized salt for cattle and horses: 4000 ppm copper
Placing salt blocks close to water source may increase intake
Genetic mutation related to copper excretion
Can occur in Bedlington terriers, labs, Dalmatians
Results in excess copper build up in the liver
Treatment usually low copper diet and medical management
Sheep and copper
Some sheep breeds and llamas are adapted to very low copper diets
Poisoned by amount of copper normally present in cattle diets
Low levels of molybdenum and sulfate in these diets also contribute
These prevent absorption and increase excretion of copper
Copper gradually accumulates in liver
When the limit is reached
Death of liver cells
Hemolytic anaemia
Prevention of copper deficiency
Prevention- only feed special, low copper, sheep mineral mixes to sheep
Role of selenium and vitamin E
Both work as antioxidants
Protects cells, esp cardiac and skeletal muscle
Source of selenium and vitamin E
Mineral salts
Fish
Meat in lower quantities
Supplementation of selenium and vitamin E
Typically a herd problem
Mineral blocks
Selenium and vitamin E deficiency
Young ruminants and equids
Sudden onset myopathy
Stiff
Reluctant to move
Recumbent
Aspiration pneumonia
Susceptibility to infection
Prevention of Selenium and vitamin E deficiency
Feed a selenium containing trace mineral
Give calves an injection of selenium-vitamin E at birth in known deficient areas
Greatly reduces calf mortality
Occasionally problem is VItamin E deficiency
Supplement with human 400 mg Vitamin E capsule
Selenium and vitamin E toxicity
Problem with some selenium accumulating plants
Over-supplementation with selenium is possible
Acute: rapid cardiovascular collapse in horses and ruminants; poliomyelomalacia in pigs
Chronic: loss of hair on mane and tail, hoof deformities, decreased reproduction performance
Treatment generally unrewarding- prevention is key
Rarely seen
Because everyone is very careful not to over supplement?
Iodine role
Helios synthesize thyroid hormones
Sources of iodine
Sea salt
Fish
Common source for humans?
Supplementation if iodine
Certain forages can interfere with iodine uptake
Oral supplementation
What is goiter and what causes it
Goiter is an abnormal enlargement of the thyroid gland
Caused by too much or too little iodine
What does an iodine deficiency in neonatal ruminants and foals look like
Goiter
Weak
Lethargy
Myxedema
Iodine and hypothyroidism in cats
Relationship between iodine intake and cause of feline hyperthyroidism is unclear
Enlargement of the thyroid glands is typically caused by a non-cancerous tumor (rarely malignant tumor,ie thyroid adenocarcinoma)
Possible contributing factors include deficiencies or excesses of certain compounds in the diet and chronic exposure to thyroid-disrupting chemicals
Iodine requirements of cats not clearly defined
Prescription Diets for Hyperthyroid
Cats
Restricted amount of iodine (not iodin-free)
Diet is not medicated
Limits amount of thyroid hormone produced
Partially controls signs
For this diet to work, it needs to be fed exclusively
Types of mineral supplementation
Direct added to food
Free choice mineral feeding
Works if there is salt in the mineral
Direct mineral added to feed is
Whole diet or concentration portion
Can be mixed in or top dressed
Intake is assured as feed is eaten
Minerals mixed with no salt should always be top dressed or mixed with ration
Free choice mineral feeding
Can be offered loos or as a block
Used for animals a pasture/fed hay
Relies on animal to seek out the mineral
Mineral supplementation usually contain
Usually contain Ca and Pi source
1:1 Ca:P supplement for pasture
2:1 Ca:P ratio supplements are used when the feed contains little calcium
Other trace minerals
The big three
Copper, zinc, selenium
Iodine too in small ruminants
Chelated minerals are
Trace mineral is an organic molecule
Better absorption
Useful if substances that inhibit absorption are present
E.g. sulfur and molybdenum which bind copper
Increase risk of toxicity
More expensive
What should mineral blocks look like
Mineral blocks/mixes should be designed so that if eat for salt intake other macro and micro minerals delivered in correct proportions
Should only feed one type of block that contains all the required minerals
Non-chelated minerals are
Requirements better understood
Inexpensive
Fat soluble vitamins
A
D
E
K
Water soluble vitamins
B
C
Role of vitamin A
Vision – precursor to retinol
Reproduction – synthesis of certain hormones
Metabolism – synthesis of proteins
Skin & Hair – regulates growth of epidermal cells and production of sebum
Source of vitamin A
Plant precursor is carotene, a vitamin A dimer (brightly colored plants rick in carotenoids)
Natural retinol sources are liver, meat, fish, eggs, dairy products
Supplementation of vitamin A
All domestic species except cats split carotene into two molecules of Vitamin A in digestive tract
Cats require pre-formed Vitamin A
Vitamin A deficiency can be caused by
Cows: stillbirths and abortions during winter following drought years
Drought conditions decrease the amount of carotene in plants, limits ability to obtain vitamin A
Head pressing, circling and other neuro sings
Growing cattle fed straw-grain diets for months
Straw is not an adequate source of energy, protein, minerals and vitamins
Need to be supplemented when using as winter feed
Blindness (permanent,, circlin, head pressing
Prevention of vitamin A deficiency
Supplementation of at risk cows
Calves born with abnormalities are unlikely to benefit from vitamin supplementation at the time
Vitamin A toxicity in cats
seen in cats fed large amounts of beef liver
Reduced growth
Soreness and sensitivity along neck and forelimbs
Skeletal malformations (bony exostoses) on radiographs
Poor hair coat, weakness, weight loss
Treatment of vitamin A toxicity
Reduce Vitamin A intake by feeding nutritionally balanced diet
Excessive bone growth not reversible
Mobility and comfort may improve once levels normalize
Vitamin D role
Calciferols are essential for absorption of calcium from GI tract
Increases intestinal absorption of Ca and P, optimizes Ca absorption from bone, reduces loss of Ca and P in urine
Source of vitamin D
Growing plants contain precursor, converted to active vitamin D by sun
Fish liver oil, oil fish (sardines, tuna), egg yolk, milk and dairy products
Meat and vegetables almost completely lacking
Vitamin D supplementation
Supplementation typically required
Routinely added to complete feeds and supplements
UV light exposure also a source
Reptiles require UV light
Vitamin D deficiencies
Deficiencies typically associated with Ca/P deficiency
Metabolic Bone Disease caused by vitamin D deficiency
Osteomalacia in adult animals
Rickets in growing animals
Weak bones, fractures
Calcium deposition along growth plates in young growing animals
Vitamin D toxicity
Excessive supplementation
Too many Vitamin D injections to cows precalving (one dose helps prevent milk fever)
Too much vitamin supplement in feeds
Supplementation of large breed puppies on a balanced growth diet
Vitamin D containing rodenticides
Consumption of plants (horses) containing active vitamin D
Vitamin D toxicity signs and physiological
Excess Vitamin D:
Elevates blood calcium and blood phosphate
See unnatural mineralization
In soft tissues including heart, walls of blood vessels and kidneys (failure)
Signs are weakness, reluctance to move, recumbency
Vitamin E role
Biological anti-oxidant, works together with selenium
Stored in body’s fat tissues, in the liver and the muscles
Source of vitamin E
Fresh green feeds
Some animal products, including liver, eggs, butter
Supplementation of Vitamin E
Added to diets to stop fat from going rancid
As supplementation
Deficiency associated with selenium deficiency
Vitamin K role
Cofactor of many enzymes; these enzymes cannot be active without Vitamin K
Required for production of blood clotting factors
Protein metabolism
Helps calcium bind to bone
Mainly stored in the liver
Source of vitamin K
Meat
Vegetables, esp cabbage,
parsley and spinach
Intestinal bacterial
Supplementation of vitamin K
Not typically added to foods
3 types:
Vitamin K1 - phylloquinone,
natural
Vitamin K2 - menaquinone,
natural
Vitamin K3 - menadione,
synthetic, less effective, more
toxic
Vitamin K deficiency is seen when
Deficiency seen when animal ingests a poison that blocks its action
Warfarin (rodent killer)
Dicoumarol in spoiled sweet clover hay
Signs of vitamin K deficiecny
Bleeding problems–bruising, petechiation, pallor, melena, hematochezia, hematomas
Weakness, lethargy, tachycardia
Treatment of vitamin K deficiency
High doses of vitamin K1
B vitamins are
A group of water soluble vitamins (12+)
Functions as co-enzymes
Body stores are low
Signs of deficiency can develop quickly. The exception is vitamin B12 which is very efficiently recycled in the body
What does vitamin B deficiency look like and is caused by
Deficiency in your ruminant results in polioencephalomalacia
Caused by ruminal bacterial overgrowth destroying thiamine
High grain promote certain bacteria to proliferate, which produce thiaminase that breaks down thiamine
Additional thiamine needs to be added prior to canning process
Signs are anorexia, ataxia, cluster seizures, twitching, vestibular disease
Raw fish may contain thiaminase
Historically blamed for thiamine deficiency in cats
Role of vitamin B1
Coenzyme for use of glucose to produce ATP
Concentrated in the heart, kidney, liver and brain
Source of vitamin b1
Ruminal bacteria
Brewer’s yeast
Meat
Bran and Cereal
Supplementation of vitamin B1
Especially important in cats
The requirement in cats is 3x that of dogs
Role of vitamin B7
Catabolism of glucose, fatty acids and some amino acids
Essential to synthesis of other fatty acids
Important for healthy skin, coat and nervous system
Source of vitamin B7
Made by intestinal bacteria
Yeasts, liver, kidney and cooked eggs
Supplementation of B7
Dysbiosis can occur with
antibiotic use – see destruction of healthy flora as well as target bacteria
Supplementation may be
necessary in certain conditions
Vitamin B12 role
Coenzyme in many biochemical reactions
Primary role in synthesis of proteins and production of red blood cells
Source of B12
Synthesized by ruminal bacterial, absorbed in small intestines
Monogastrics make B 12 in large intestine (poor absorption)
Animal products – liver, kidneys, meat
Supplementation of B12
Very efficiently recycled
Injection may be needed to
help treat anemia
B12 deficiency looks like
Deficiency signs include anemia and, in ruminants only, ketosis
Cobalt is required for ruminal microbes to synthesize vitamin B12
Also essential for utilization of propionic acid
Therefore, in cobalt deficiency, can see both B12 deficiency and ketosis secondary to utilizing propionix acid to make glucose
Riboflavin helps with
Riboflavin (B2 )
* Contributes to animal’s skin and coat health
* Essential in production of energy from fat, and catabolism of amino acids
niacin is good for
- Helps body produce energy from fat and sugars
- Promotes synthesis of skin lipids
panthothenic acid/pathothenate is good for
Pantothenic acid / pantothenate (B 5 )
* Involved in metabolic reactions to produce energy for the cells
* Promotes synthesis of skin lipids
Pyridoxine (B6) is good for
- Coenzyme that plays role in
different metabolic reactions, esp that of amino acids
Folic acid is good for
- Development of tissues of the nervous system
- Fetus works like a folic acid pump and deficiency can develop if mother not receiving enough
Role of vitamin C
Neutralizes free radicals
Permits the regeneration of Vitamin E
Metabolizes iron
Source of vitamin C
Fruits! Esp citrus fruits, beries, kiwis and strawberries
In dogs and cats, synthesized in the liver from glucose
Vitamin C supplementation
Only required in primates, guinea pigs and fruit bats
Can be a problem if not fed fruits and vegetables
Synthesized by all other species
