Lecture 2b - Review of Nutrients Flashcards
Energy is not a nutrient, so what is it derived from?
Macronutrients!
- lipids, carbohydrates and proteins
What happens with N and a carbon skeleton when fed an excess protein diet?
Excess protein diet = animal has excess aa
- through deamination the bond btw the N and C skeleton is broken
- C skeleton undergoes gluconeogenesis or ketogenesis
- 2 N will link to form UREA which is brought to the kidney and excreted
What happens when energy supply > use?
Animal would grow; excess energy stored as fat in adult animals
How is gross energy content in food determined?
With a bomb calorimeter
- burning of food and measurement of amount of heat released
What are the advantages to the net energy system?
- more precise than ME and DE
- actual energy amount that is available to the body from digestion and metabolism of feed
- efficiency of energy utilization
What are the disadvantages of net energy system?
- more experimental data needed
- heat loss must be measured
At present, what energy system is used in dog and cat nutrition?
Metabolizable energy (ME)
What is basal metabolic rate (BMR)?
The energy requirement for a normal animal in a thermoneutral environment, awake but without movement (resting) and in a postabsorptive (fasting) state
What is resting fed metabolic rate (RFMR)?
- The energy requirement for a normal but unfasted (fed) animal at rest in a thermoneutral environment
- Includes energy needed for digestion, absorption and metabolism of food (heat increment)
What is maintenance energy requirement (MER)?
The energy requirement of a moderately active adult animal in a thermoneutral environment
- includes energy needed for obtaining, digesting and absorbing food in amounts to maintain body weight as well as energy for spontaneous activity
- does NOT include energy needed to support additional activity (work, gestation, lactation and growth)
What is the most important nutrient?
Water
- if you without food and water, water gets the animal in trouble the fastest
- largest constituent of the body, varying from 40 to 80%
What are 3 sources of water?
- fresh (drinking) water
- water in food
- metabolism
How is water produced in metabolism?
When sugars are oxidized
- Glucose + O2 —> CO2 + H2O
What are the ways an animal losses water?
- Urine (largest loss (75-85%)
- Feces (second largest)
- Respiration (water vapor lost from lungs in exhaled air)
- Sweat
- Milk during lactation (85-90%)
What are the 4 fxns of water?
- Solvent to dissolve and transport substances
- Necessary for chemical rxns that involve hydrolysis
- enzymatic digestion of CHOs, fats and protein - Regulation of body temperature
- evaporative cooling - Provides shape and resilience to body
Water acts as a solvent to dissolve and transport what substances?
- ion balance across cellular membranes
- transport of nutrients within and among cells
- elimination of waste products through urine
What systems regulate the amount of water in the body?
- Neural and endocrine systems
What is dehydration?
Lack of water in body tissue
- >1% loss is when thirst drive kicks in
- 5-10% water loss in cells could result in death
What is hydremia?
Water intoxication. 2 animals who should not have free access to water:
- young animals that consume a large amount of water in a short time
- dehydrated animals
What happens in the body (cells) during dehydration?
Cells shrink and die off
- this is happening in the organ systems which leads to death in the animal bc organs are shutting down
What are 6 key defining factors about vitamins?
- required in very small amounts (ppm)
- not metabolic fuels or structural nutrients
- involved in fundamental fxns of the body
- regulators of rxns (catalysts)
- absence must cause deficiency syndrome
- not synthesized in sufficient quantities to support normal physiologic fxn
Are all vitamins essential for all species?
No
- some species are able to make certain vitamins while others are not
What are the number of essential vitamins for dogs vs cats?
Dogs: 3 fat-soluble and 8 water-soluble
Cats: 4 fat-soluble and 9 water-soluble