Nutrition Midterm 1

How many classes of nutrients are there? What are they?

• 6

• Carbohydrates

• Fat

• Protein

• Vitamins

• Minerals

• Water

What is the first requirement to be met in an animals diet?

Energy needs / requirements

What are the ways energy is measured in nutrition?

• calories

• kilocalories (kcal)

• Joules

• Kilojoules

What is RER

Resting energy requirement which is the energy needs at rest

Define essential nutrients vs nonessential

• essential nutrients must be obtained in the diet, the body can’t produce it or not enough (ex vit c in guinea pigs and humans)

• nonessential nutrients are naturally synthesized by the body

Explain macronutrients vs micronutrients

• macro are energy producers/ can be converted to sugars - includes proteins, fats, and carbohydrates

• micro maintain crucial body function but DONT produce energy - includes vitamins and minerals

explain undernourishment vs malnourishment

• under = not getting enough calories

• mal = long term absence of one or more essential nutrients from diet

define mechanical vs chemical digestion

• mechanical = physical breakdown of food - chewing and peristalsis

• chemical = enzymes - like amylase and protease

What is the most important nutrient?

WATER! up to 80% of body, 60% of adult animals

Where is water in the body?

• 2/3 intracellular

• 1/3 extracellular (interstitial space & intravascular space)

What are the functions of water (hint 7)

• transport nutrients and excretions

• metabolic reactions / hydrolysis

• body temp regulation

• lubrication of joints and organs

• organ structure and shape

• water volume contributes to BP

• balances electrolytes

what are the levels of water loss and what they cause?

• 5% = sluggishness

• 10% = serious illness

• 15% = death

How does water increase?

• free water intake

• food

• metabolic water

what are the sources of water loss?

• urine

• feces

• evaporation (panting, sweating)

• lactation

• illness (fever, vomiting, diarrhea)

what is the chemical composition of carbohydrates?

Carbon, Hydrogen, and Oxygen

What is the primary function of carbohydrates?

energy

what is the most important carbohydrate? why?

• glucose

• most abudant CHO

• primary source of energy of all cells of the body

• preferred energy source for blood and CNS cells

• aka DEXTROSE

what are the sources of glucose?

• digestion of starches

• hydrolysis of glycogen in body stores

what does a simple carbohydrate (CHO) consist of?

1-2 sugar units

what does an oligosaccharide (CHO) consist of?

short chains of 3-10

what does a complex carbohydrate/ polysaccharides consist of?

100s or 1000s of units

what are the monosaccharides?

• glucose

• fructose

• galactose

what are the disacchrides? (makeup and important ones)

• two sugars

• maltose (glucose + glucose) product of fermentation digestion

• sucrose (glucose + fructose) common in plants

• lactose (glucose + galactose) only carbohydrate of animal origin

what is special about oligosaccharides?

often difficult to digest, may cause flatulence

what is important about fructooligosaccharies?

• supply food to the microbiome (but too much can cause GI upset which is important for large animal)

• prebiotic effect

• can reduce fecal odor

• can improve immune function

what are starches?

large CHOs made of many glucose molecules

what is glycogen?

created by the liver & muscle for storage of excess sugar molecules

how do starches and fiber differ?

• starches have alpha bonds which can be broken down by animal enzymes into glucose

• fiber has beta bonds which are resistant to animal enzymes and need microbes for digestion

Explain soluble fiber

• fermentable

• microbes can ferment it into short chain fatty acids / volatile fatty acids like acetate propionate, and butyrate

• VFAs provide energy for enterocytes & microbes so support gut health

• prebiotic effect

• makes feces softer

Explain insoluble fiber

• nonfermentable so bacteria cannot convert it to energy

• bulks up stool, speeds up transit, prevents constipation

• ex: cellulose, lignin

• does not absorb water

• increases fecal bulk , but doesnt soften stool

• promotes satiety

what can happen with excessive starches in cattle and horses?

• horses: excess starch can risk colic, laminitis, and hindgut acidosis (increased risk of inflammatory conditions)

• cattle: starch needs to be balanced with fiber otherwise you risk ruminal acidosis

why are cats less adapted to utilize CHOs?

• no salivary amylase

• no sweet receptors on the tounge

• low enzymatic energy for them

• intestinal sugar transport system less capable at handling various sugar levels

• lack hepatic glucokinase activity which is important for glycogenesis

what types of animals is fiber most important for?

• major energy source for grazing animals

• microbes in gut ferment SCFA/VFAs which ruminant and hind gut fermenters then can covert into glucose via gluconeogenesis (simple monogastrics cant)

where are carbohydrates digested?

mouth (if amaylase is present) → duodenum → portal vein → used for energy and stored in livers and muscle as glycogen

what are triglycerides made of?

• glycerol + 3 fatty acids

how much energy is 1 gram of fat? how does it compare to protein and carbs?

• 1 gram fat = 8.5 kcal of energy

• almost 3x the energy of protein and carbs

• also more digested protein & carbs

what is the role of fat? hint 5 things

• energy storage

• insulation

• protection of vital organs

• provides essential fatty acids

• carrier for fat soluable vitamins

where is fat digested?

the duodenum

how is fat digested?

• in the duodenum bile acids emulisfy fat into smaller droplets and pancreatic lipase acts on the droplet surface to break down triglycerides

• monosacchardies and fatty acids passively enter the enterocyte, inside the cell they are reassblemed into triglycerides, and then packed into chylomicrons that enter the lymphatics and blood stream

what is the most important dietary fat and its structure?

• triglycerides

• 3 fatty acids linked to one glycerol

explain saturated vs unsaturated fatty acids

• saturated = contain no double bonds, stable, animal fats

• unsaturated = contain one or more double bonds, less stable, vegetable fats

what is the structure of essential fatty acids

• polyusaturated fatty acids (PUFAs)

• long chained

• typically 8 carbons or longer

what are the two major essential fatty acids?

• Linoleic acid (LA), omega 6 fatty acid, essential for all mammals, precursor to arachidonic acid (except cats cant convert it so they need archidonic acid directly)

• alpha linolenic acid (ALA), omega 3, precursor to EPA and DHA (3 letters, omega 3, salmon & fish oil, support skin & coat

what does LA and ALA do?

• most animals survive just on LA, precursor to pro-inflammatory eicosanoids which help fight infection and heal injury

• ALA converts inefficiently to EPA and DHA which support skin & coat, supports eye, brain, retina, and nervous system health

explain omega 3 and omega 6

• omega 3 is anti-inflammatory, competes with omega 6 for the same enzymes, important for keeping omega 6 inflammation under control

• omega 6 promotes inflammation, normal response to protect against pathogens and normal response to injury

what are signs of EFA deficiency (hint 6)

• skin and coat problems

• infertility

• failure to thrive / poor growth

• nero abnormalities

• poor vision

• altered blood clotting

can be reversed

explain cholesterol

• essential lipid for life

• NOT used for energy

• synthesized in the liver, found in diet in eggs, meat, and dairy

• functions:

  • cell membrane structure

  • forms bile salts for fat digestion

  • used to make steroid HORMONES

  • made into vit D with help of sunlight

  • protective layer of the skin