Exam 3 Material Flashcards
mineral classification
7 macro (major) elements and > 16 micro (trace) elements are required
- Microminerals: are present in body tissues at small concentrations (<50 mg/kg or <50pp)
- Macrominerals: are present in concentrations larger concentrations
nutritionally important major essential minerals
calcium phosphorus potassium sodium chlorine sulfur magnesium
nutritionally important trace essential minerals
iron zinc copper molybdenum selenium iodine manganese cobalt
mineral absorption in the SI
micromineral absorption: duodenum, jejunum, and ileum
macromineral absorption: jejunum and ileum
functions of minerals
Enzyme activation (most essential minerals catalyze >1 cell reaction) Acid-base and water balance (Na+, K+, Cl-) Skeletal structure (Ca, P, Mg in bone; S in keratin) Unique functions EX: Fe in heme: Co in vitamin B12; I in thyroid hormones
factors affecting mineral requirements
Physiological state/level of production
Interactions with other minerals
Tissue storage
Form fed
deficiencies and excesses of minerals
Most minerals have an optimal range, below which deficiency symptoms occur, and above which toxicity symptoms occur
Mineral content of soils dictates mineral status of plants and; therefore, feeds
-Plant stage of maturity can affect mineral content and nutritional interactions
Deficiency or toxicity symptoms may take months to develop
calcium
About 99% of the Ca stored in the animal body is in the skeleton (bones and teeth) Can draw on Ca stored in bone to maintain consistent level in blood to tissues Major role: structural (bone) Additional functions: -Blood clotting -Rhythmic heart action -Neuromuscular excitability -Enzyme activation -Permeability of membranes
calcium in the diet
Good sources: Legumes, green leafy crops Milk, meat, and fish Supplements such as limestone, Dical (mix 28% Ca, 18% P), oyster shell Poor sources: cereals and roots
phosphorus
Composes approximately 1.1% of the fat free body
Present in organic form in soft tissues…where have we seen them?
Lipid transport, cell-membrane structure
Bioenergetics
80% of body P is in bone
phosphorus in the diet
Good sources:
Milk, meat, and fish
Grains: variable (due to phytates)
Poor sources: forages and crop residues
bioavailability of P in feed sources-Factors affecting intestinal absorption:
- Ca:P ratio
- Large intakes of Fe, Al, Mg interfere with P absorption
- P contained in phytate salts (esp. cereals) is biologically unavailable unless have phytase
bioavailability of P in feed sources-use of phytase to improve P availability
Dietary supplementation with synthetic phytase
-Increase intestinal absorption of P
-Decreased need for supplementation inorganic P
-Decreased P excretion, environmental pollution
Other approaches
-Genetic engineering of plants
-Genetic engineering of animals
important concepts about Ca and P
Both Ca and P are required for normal bone formation, as well as many non-skeletal functions
Ratio of Ca to P in diet is as important as the absolute level of either mineral-1:1 or 2:1 is good for most animals (Exception: laying hens need more Ca)
Deficiency of Ca, P, (or Vitamin D), causes:
-Rickets in growing animals
-Osteomalacia in adults
-Milk fever (hypocalcemia, parturient paresis) in lactating animals
magnesium
50% of body Mg is in bone
Associated with Ca and P
Mg in soft tissues is concentrated within cells (liver, skeletal muscle have highest soft tissue concentrations)
Major role:
-Bone structure
-Important enzyme activator, especially for energy transduction reactions
-Regulation of ion channel function EX: Na+, K+ ATPase activity in skeletal muscle
magnesium deficiency symptoms
Growing rats: anorexia, decreased weight gain, nervous irritability, tetany
Pigs: skeletal malformations, nervous irritability, tetany, death
Milk-fed calves: hypomagnesemia, decreased bone Mg, tetany
Adult ruminants fed lush pasture: hypomagnesemia, tetany (or grass staggers), death
magnesium in the diet
Good sources: -Wheat bran -Legumes -Most protein concentrates -Supplement: magnesium oxide (MagOx) Poor sources: -Forages (variable)
the electrolytes
Potassium
Sodium
Chlorine
Major role in acid: base balance in the body
-Kidney excretes excess Na and K as one method to maintain blood pH homeostasis
acid-base balance
Involves interaction of cations (Na, K) and anions (Cl, S)
Important to monitor the dietary cation: anion difference (DCAD)
-This is the acid: base balance
Basic equation: (Na + K)-(Cl+S)
-Ca, Mg, P, HCO3- can also be included in the equation
DCAD
If its <0, then the animal will mobilize cations to compensate and will try to buffer to increase pH
-The animal in a state of ACIDOSIS
If its >0, then the animal will mobilize anions to compensate
-The animal will be in a state of ALKALOSIS
Animals typically ~10-20 mEq/l
iron
Poor Absorptive Efficiency: -Heme (~15%), Fe2+ (<5%), Fe3+ (trace) Major role: -O2 transport in blood (hemoglobin) and muscle (myoglobin) -Cofactor in oxidative reactions Deficiency: Anemia (common in piglets)
zinc
Absorbed at about 20-30%
Major role:
-Component of many important enzyme (>200)
-Stabilization of membranes
-DNA binding
-Oxygen radical metabolism
Deficiency (caused by high Ca, high Cu, phytates): parakeratosis, depressed growth performance
selenium
In all cells of the body
-Liver, kidney, muscle contain the highest
Component of glutathione peroxidase
-Protects cellular membranes from peroxide
Component in other selenoproteins
Stored as selenomethionine and selenocysteine
Interacts with Vitamin E
Deficiency: nutritional muscular dystrophy (white muscle disease), exudative diathesis, liver necrosis ill thrift (ruminants), reproductive problems
Toxicity: alkali disease, blind staggers
manganese
High requirement for poultry -High Ca impairs Mn absorption -High Fe impairs Mn absorption Toxic at high levels for pigs Deficiency: retarded growth, skeletal abnormalities (lameness in pigs), ataxia, reproductive failure, perosis or slipped tendon, reduced shell thickness, fatty livers
iodine
Important for the synthesis of hormones thyroxine (T4) and triiodothyronine (T3)
Function in lipid, carbohydrate, nitrogen metabolism, regulation of energy metabolism, growth and development, reproductive performance
Deficiency: Goiter
Diet induced: high intakes of brassica crops, soybeans, linseed, peas
Toxicity: depressed performance
cobalt
Constituent of Vitamin B12
Incorporated into B12 by bacteria
Can’t make B12 if you don’t have cobalt
Deficiency:
Occurs in ruminants (“wasting disease”)→ result of B12 deficiency but B12 deficiency is caused by Cobalt deficiency
Inability to synthesize vitamin B12
Symptoms: anemia, listlessness, lack of appetite (sometimes causing death)
Most severe deficiencies in the US are in New England and lower Atlantic plain
Coastal regions
Supplementation: sulfates, Co-I salt, Co bullets, fertilize with CoCO4
vitamin classifications
fat soluble: ADEK
water soluble: B, C
features of vitamins
Chemically and biologically diverse, and therefore hard to classify
Not metabolic fuels (like glucose, fatty acids) or structural nutrients (like amino acids, Ca, P)
Mostly catalysts (facilitators) of the metabolism of other nutrients
All vitamins are metabolically essential but not all are necessarily required in the diet, depending on the diet and the vitamin concerned
Examples:
-Most mammals can synthesize vitamin C (ascorbic acid), primates (incl. humans) cannot
-No mammals can synthesize B vitamins but ruminants obtain adequate supply from bacterial synthesis in the rumen
provitamins
function as vitamins only after undergoing a chemical change in the body EX: beta-carotene→ vitamin A
Many vitamins interact with other nutrients, most notably minerals:
White muscle disease in young ruminants: Se, vitamin E Cobalt deficiency in ruminants (wasting disease): Co, vitamin B12 Milk fever (parturient paresis) in dairy cows: Ca, P, vitamin D
