Animal Nutrition Exam 1

What is the main definition of nutrition?

* interrelated steps by which a living organism assimilates food and uses it for
* growth
* tissue repair and replacement
* elaboration of products

What else is included in the definition of nutrition?

* processes that transform food into body tissue and activity
* integrative
* biology
* physiology
* chemistry
* math
* science
* using, replacing body nutrients
* Links
* G x E = P
* genotype x environment = phenotype
* tool
* influence animal to drive production - exercise/activity, lactation, growth, gestation
* well-being and productivity

what is the equation for phenotypes

phenotype = genotype x environment

6 nutrient classes

* vitamins
* carbohydrates
* proteins
* lipids
* water
* minerals

which of the 6 nutrient classes are micronutrients?

* vitamins
* minerals

which of the 6 nutrients classes are macronutrients?

* carbohydrates
* proteins
* lipids

is water a micronutrient or a macronutrient

neither

what is a nutrient?

* any chemical substance that provides nourishment to the body
* necessary to support life
* 40-50 nutrients

What did Lavoisier do?

* one of the discoverers of oxygen
* promoted idea that animals “combust” food (burn)
* guinea pig with ice and calorimeter
* same heat per amount of CO2 was produced by fire-burning or guinea pig
* heat = energy
* can be released through burning and metabolism
* law of conversion of mass
* LaPlace Ice Calorimeter
* put mouse in chamber and measured water produced in a 10-hour period
* mouse melted 370 grams of ice
* takes 334 J/g to melt ice
* 370 g (334 g/1g) = 12,334g/h
* 2.95 kcal/hour
* armsby calorimeter
* established some energy estimates for animal feed
* such as protein
* amino acids → nitrogen → protein in body

What did Magendie do?

* N2
* “Can animals get Nitrogen from the atmosphere?”
* experiment on dogs involving protein-free diet (sugar, olive oil, butter)
* dogs died

What did Liebig do?

* muscle - nitrogen
* source: protein was used for energy

What did Edward Smith do?

* test idea that protein is used for energy
* treadmills
* days on → increased urea
* days off → decreased urea
* not much difference

urea

proteins for food

What did Fick and Wiscenus do?

* 1866
* measured urea while doing work
* climbing mounts - work = energy
* collect their own urine
* energy, protein, and urea produced allowed them to calculate from protein
* energy wasn’t protein
* carbohydrates and lipids were energy

1900s Vitamin Era

* Wisconsin
* protein amount correlation with energy
* feeds → protein energy

What did Babcock and Hart do?

* heifers experiment
* fed heifers corn, wheat, and oats
* resulted in equal protein and energy concentrations
* after heifers reached gestation, they got sick and birthed dead calves
* wheaty heifers → dead calves
* corn heifers → fine (yellow)

What did E.V. McCollum do?

* Wisconsin
* rats - casein - protein diet
* lard: lipid
* eggs (yellow)
* extract of egg with fatty component picked up yellow color
* yellow extract was capable of supporting the rats
* factor A → vitamin A
* water soluble → vitamin B

What is the body made up of?

* organs
* kidneys, lungs, etc.

what are organs made of?

* tissues
* connective, epithelial, nervous, etc.

what are tissues made of?

cells

what do cells contain?

* organelles
* mitochondria, endoplasmic reticulum, etc.

what are we talking about when we speak about molecules in a cell?

* proteins (amino acids)
* lipids (phospholipids, cholesterol, fatty acids)
* nucleic acids

what is the major carbohydrate in the body

glycogen

what is the structure of proteins

* polymers

what are polymers

repeating units of amino acids

what are we ingesting when we ingest feeds

* molecules
* our body doesn’t use complex foods and absorb them whole
* we absorb simple molecules that get used to build bigger molecules

How do we build up materials and burn energy

metabolism

the capacity for fermentation dictates:

* what the nutrient profile is
* feed types
* gastrointestinal tract structres

Animals that ferment at a high capacity

allows for consumption of fibrous plant material

Some animals do little fermentation

* there is reduced utilization of plant material
* tend to eat things other than plants
* forces you to eat highly digestible, less fibrous foods

digestion definition

* preparation of feeds for absorption
* taking very complex materials and getting them down to simple units
* chewing and grinding
* muscular contractions of the gastrointestinal tract
* chemical actions

chewing and grinding in digestion

when eating something complex/large in structure, it has to be broken down

muscular contractions of the GI tract functions to

further reduce the size and mix

chemical actions involved in digestion

* acid
* hydrolytic enzymes

absorption definition

* simple units from digestion are moved from the exterior of the body to the interior
* passage of small molecules across the epithelium of the gut into circulation

where is the lumen of the gut?

exterior to the body

what does the lumen of the gut do?

* moves units from the exterior to the interior of the body
* absorption

functions of the gut

* prepare feed for absorption (digestive process)
* storage of feed prior to absorption
* microbial action on feeds (fermentation)
* environment for bacteria to reside
* facilitate nutrient absorption

how long do simple stomach animals store feed prior to absorption?

* 24-48 hours
* cats, pigs

how long do ruminants store feed prior to absorption

* feed resting in the gut for 80-100 hours
* depends on how fibrous the material is
* more complex feed remains in the stomach longer

what is the range of time feed is stored prior to absorption?

1 day to 4 days

how is the gut using microbial action on feeds?

* microbes & bacteria are carrying out fermentation in the gut
* bacteria extracts nutrition from food/feed animal consumed

how does the gut provide an environment for bacteria to reside?

* symbiotic relationship
* providing home for bacteria so they will reside in the gut and carry out fermentation

what influences GI physiology?

fermentation

fermentation allows for

The use of fibrous plant material because they have lower digestibility

are non-ruminants simple stomached or monogastric?

simple stomached

where does fermentation take place in non-ruminants?

hindgut

non-ruminants have lower/higher utilization of fibrous plant materials

lower

are ruminants simple stomached or monogastric?

* monogastric
* complex stomach

are ruminants capable of using fibrous plant material?

* yes
* they can effectively use fibrous plant material

do non-ruminants or ruminants chew cud?

ruminants

what is chewing cud?

regurgitation of food for reduction of particle size

how many stomach compartments do simple stomached animals have?

one

herbivores

* complex large intestines
* less fermentation capacities than herbivores
* incisors adapted for biting off small amounts of food
* molars for grinding

carnivores

* food is easy to digest
* up and down chewing
* teeth for tearing tissues of animals
* molars/premolars are pointed for shredding

how many salivary glands are there?

4 glands

discuss salivary glands

* saliva is added during chewing
* some animals have digestive enzymes in their saliva
* digestion starts in the mouth by salivary enzymes

mastication

chewing

what digestive enzymes are in the saliva?

* salivary amylase
* salivary lipase
* varies by animal if they have digestive enzymes or not

functions of the stomach

* mixing and storing food with components being secreted in the stomach
* animals want to maximize digestion to the greatest extent
* gradual release into the small intestine
* no appreciable absorption of nutrients in the stomach

what is the pH of the stomach?

* 1.5 to 3.5 due to acid secretion
* bactericidal
* initiates digestion

why is there no appreciable absorption of nutrients in the stomach?

the stomach just participates in digestion but doesn’t contribute to absorption of nutrients

small intestine functions

* digestion
* absorption

small intestine length

* variety in length
* typically shorter in carnivores

where are villi located?

* throughout the small intestine
* length varies along small intestine

what do villi have that aids in digestion?

enzymes on their surface

How do villi contribute to absorption?

* they have a huge amount of surface area
* cells lining surface are specifically geared towards absorption
* water soluble → venule → blood
* fat soluble → lateral → lymph
* villi are lined with enterocytes that have enzymes to ensure nutrients are small enough to be absorbed

regions of the small intestine

* duodenum
* jejunum
* ileum

duodenum

* collects secretions from pancreas
* collects bile from the liver
* contributes to digestion

what is the active site of digestion?

the duodenum in the small intestine

jejunum

* contributes to digestion
* major function is absorption
* villi start to get longer along the length of the small intestine

ileum

continues absorption

the horse is _________ and the pig is _____________

* herbivorous
* omnivorous

why do herbivores have greater fermentation capacity?

* more sacculation
* make a lot more VFA’s

large intestine

* fermentation
* absorption of water, B vitamins, Volatile Fatty Acids (VFAs)
* sacculation

where is the cecum located?

large intestine

do all animals have a cecum

* no
* some just have a colon

what is another term for volatile fatty acids (VFAs)?

short-chain fatty acids (SCFAs)

what is sacculation?

compartments of the large intestine

what does sacculation do?

* increase surface area
* facilitates fermentation

cecum

* has sacculations
* help facilitate mixing of digesta
* increase absorption surface area

why do carnivores have minimal long intestine?

don’t need the capacity

what is the main difference between animals?

* how herbivorous they are
* an example of a herbivorous, simple-stomached animal is the horse

coprophagy

the consumption of feces

why is coprophagy done?

* to maximize nutrition from the diet because of the role of fermentation int he hindgut
* opportunity to get a second pass on fiber

hindgut

last portions of the gut

what animal performs coprophagy?

* rabbit
* rabbits perform coprophagy to harvest greater amounts or protein quality

discuss the feces in coprophagy

* soft stool, generally produced in the morning
* bacteria-rich
* also rich in B vitamins

why do some animals perform coprophagy to get a second pass on fiber?

* fiber sometimes doesn’t get thoroughly digested
* second pass results in even greater digestion of fiber
* higher nutrient yield

are birds simple-stomached or monogastric?

simple stomached

what differences are there in the mouth of birds compared to mammals?

they have a beak (no teeth)

stomach functions of the bird

* birds need to hold food prior to digestion
* acid digestion prior to entry into the small intestine

organs of the bird involved in digestion/absorption

* crop
* proventriculus
* gizzard
* paired ceca (2 cecum)

crop functions

* hold food
* soften food

proventriculus

where acid digestion is initated

gizzard

* muscular organ
* provides a grinding function
* functions as a mouth by reducing the size of feeds

discuss the red-tailed hawk

* carnivore
* crop size is large

what influences the capacity of digestion in animals?

the type of diet

points along the digestive tract where digestion starts

* saliva
* stomach
* use of acid
* intestine

what salivary enzymes are used for starch and lipase?

* salivary amylase for starch
* salivary lipase for triglycerides