2b Review of Nutrients 1 Flashcards
What are the 5 basic functions of nutrients?
- act as structural components
- enhance chemical reactions of metabolism
- transport substances into, throughout or out of the body
- maintain body temperature
- supply energy
Define essential nutrient
nutrient that cannot be synthesized by the animal, and must be obtained in the food
Define conditionally essential nutrient.
A non essential nutrient that becomes an essential nutrient when certain physiologic conditions result in relative deficiency
Define non essential nutrient
a nutrient that can be synthesized in adequate quantities by animals and are not specifically required in the food
What are some certain situations in which a nutrient would be conditionally essential?
- growth
- lactation
Define digestibility.
the percentage of food’s gross nutrient content released following mechanical and chemical digestive processes
Define bioavailability.
the degree to which a nutrient becomes available to support metabolism after digestion and absorption
What 2 things is digestion influenced by?
- food characteristics
- digestive efficiency of the host
What is an example of nutrients that are sometimes digestible but not available?
- Maillard reaction
- sugar and protein are linked so lysine cannot be included in protein and is excreted in urine
Define apparent digestibility.
nutrient intake minus nutrient excretion in feces
Define true digestibility.
nutrient intake minus nutrient excretion in feces corrected for intestinal endogenous losses
Define intestinal endogenous losses.
excretion of nutrient into gut due to cell turn over, intestinal secretions, sloughing of intestinal cells
What are some examples of intestinal secretions?
- bile
- pancreatic enzymes
- HCl
- mucus
What are the two types of simple carbohydrates?
monosaccharides and disaccharides
What are 3 types of monosaccharides?
- glucose
- fructose
- galactose
What are 3 types of disaccharides?
- maltose
- sucrose
- lactose
What are the 2 types of complex carbohydrates?
- oligosaccharides
- polysaccharides
What are 2 examples of oligosaccharides?
- fructooligosaccharides
- galactooligosaccharides
What are 3 examples of polysaccharides?
- starch
- cellulose
- glycogen
Which type of glycosidic bond is in carbohydrates which are digestible by mammalian enzymes?
- alpha
Which type of glycosidic bond is in carbohydrates that are digestible by bacterial enzymes?
- beta
What are some example of carbs that contain alpha bonds?
- sucrose
- maltose
- lactose
- starch
- glycogen
What are some examples of carbohydrates that contain beta bonds?
- oligosaccharides
- non starch polysaccharides (cellulose, hemi cellulose, pectin)
How do NSPs relate to dietary fiber?
NSP + lignin = dietary fiber
Do glucose and VFA provide the same amount of energy when absorbed?
no, glucose is preferential as VFAs must be converted
What are the 3 types of starch?
- rapidly digestible starch
- slowly digestible starch
- resistant starch
What 3 things does the amount of starch type depend on?
- starch source
- starch type
- extent of processing
What is the difference between the 3 types of starch?
- ratio of amylose to amylopectin
- high amylose = highly resistant
What are some examples of starch sources?
corn, wheat, rice, barley, oats, potatoes, pulses
What are the 5 functions of carbohydrates?
- energy, source of heat, DNA and RNA framework, building block for other nutrients, storage of energy
How is energy produced from carbohydrates?
TCA cycle
Define prebiotics
a selectively fermented ingredient that allows specific changes, both in the composition and activity of the GI microflora that confers benefits upon host well being and health
Can mammals digest probiotics?
- contain beta bonds so mammals cannot
What are the 4 functions of dietary fibre
- increase in bulk and water in intestinal contents
- regulate normal bowel function
- fermentation end products important in maintaining colon health
- fermentation decreases colonic health
What is one disadvantage of fibre?
may interfere in other absorption of nutrients
What do you need to produce fermentation end products?
energy (fibre) and nitrogen
Do dogs and cats have a protein requirement?
nooo they have an AA requirement
What is the first limiting amino acid in a plant based diet?
lysine
What are some essential AAs?
- phenylalanine
- lysine
- isoleucine
- leucine
- valine
- methionine
What are some conditionally essential AAs?
- cysteine, glutamine, tyrosine
What are some non essential AAs?
- alanine
- glycine
- proline
- serine
What is another name for taurine?
- beta amino sulfonic acid
Why is taurine important in cat diets?
- normally made in all animals but cats cannot make enough as rapid AA metabolism
- needed for taurocholic acid and critical element of opsin (eye function)
What are some biological functions of proteins?
- principal organic chemical constituents of body organs and soft tissues
- cell membrane structure and function
- enzymes
- hormones
- immune factors (antibodies)
- fluid balance
- acid base balance
- transport
- source of energy and glucose
Describe the concept of the first limiting amino acid.
- Protein synthesis cannot proceed without an adequate supply of all AAs that contribute to the primary structure of that protein
- protein synthesis stops when not enough of one amino acid
What is ‘biological value’ of proteins?
- the ability of a specific dietary protein to supply amino acids in the relative amounts required for protein synthesis by body tissues
- influenced by AA composition
- varies with species, physiological and nutritional status
What is an ideal protein?
- biological value = 100
- egg
- AAs in perfect balance relative to AA requirements of the animal
What are some examples of sources of protein?
- eggs
- meat
- milk
- pulses
- seeds
Define lipids
Organic substances that are insoluble in water and soluble in organic substances
What are the 5 major lipid classes?
- fatty acids
- triglycerides
- phospholipids
- sterols
- waxes
What are 5 functions of lipids?
- energy
- energy storage
- essential fatty acids
- fat soluble vitamin absorption
- insulation
Where is fat stored in the body?
- adipose tissue
What type of fat is storage fat?
saturated and monounsaturated
poly unsaturated fatty acids are usually fats high in what kind f acid?
linoleic
What are some sources of fat?
- fat stores of land/marine animals
- seed oils
- nuts
- eggs
What are the main fat sources for dogs and cats?
plant based
The longer the fatty acid chain, the more ______.
- more water insoluble
- solid at room temp (higher melting point)
- decrease in volatility
What kind of fatty acids do dogs and cats not like?
medium chain fatty acids
Where are short chain fatty acids produced in the body?
- large intestine/cecum
Are long chain saturated fatty acids more or less digestible?
- less
Why do poly unsaturated fatty acids require more dietary vitamin E?
because of double bonds, they are oxidized more easily (become rancid)
What are the 3 classes of unsaturated fatty acids?
omega 3/6/9
Do trans and cis double bonds lead to straight or bent fatty acids?
- trans = relatively straight
- cis = bent (more space = less packed)
What are the 2 essential fatty acids?
linoleic acid (omega 6) alpha-linolenic acid (omega 3)
What are the functions of omega 6 essential fatty acids?
- growth
- reproduction
- eicosanoid/prostaglandin synthesis
- cell membrane fluidity and skin health
What are the functions of omega 3 essential fatty acids?
- brain and retinal function
- cell membrane fluidity and skin health
What are some essential fatty acid deficiency problems?
- reduced growth
- reproduction problems
How can you determine the gross energy content in food?
- bomb calorimeter
- burning of food
- measurement of amount of heat released
What is the unit of measure for energy?
- joule or calorie
- 1 calorie is the amount of energy required to increase the temperature of 1g of water by 1 degree
What are some advantages of 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 some disadvantages of the NE system?
- more experimental data needed
- heat loss must be measured
What energy systems are used in livestock and pets?
- livestock: all 3
- pets: ME
Define basal metabolic rate (BMR)
the energy requirement for a normal animal in a thermoneutral environment, awake but without movement (resting) and in a postaborptive (fasting) state
Define resting fed metabolic rate (RFMR)
- the energy requirement for a normal but unfasten animal at rest in a thermoneutral environment
- included energy needed for digestion, absorption and metabolism of food (heat increment)
What does thermoneutral mean?
- no extra energy required to maintain body temp
Define maintenance energy requirement (MER)
- the energy requirement of a moderately active adult anima 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)
