Animal Nutrition ANSC 3373 Exam 1- GI Tract

Lavoisier

Father of nutrition

1800s (19th century)

Started to understand nutrients; true basic understanding of proteins, carbs, and lipids

1900s (20th century)

Biggest discovery: vitamins and minerals

New knowledge

Learning how important vitamins and minerals because technology; always learning more. Herbs; amino acids

Nutrition

A science which deals with the processes by which an animal takes in and utilizes food/feed resources or substances through mechanical, chemical, and enzymatic reactions and physiological process.

Nutrient

A group of food/substances of similar chemical composition which aids in the support of life. Water, protein, carbohydrates, lipids, vitamins, minerals.

Feedstuff

"Stuff" to make the animal eat that contains nutrients

Balanced ration

One that meets the needs of the animal

Ab libidum

At the animals choice. Have to have enough resources

Bolus

Wad of feed stuff that is swallowed-> what goes in

Cud

What comes back up in ruminants-> includes things from GI tract

Digesta

Feedstuff and secretions from GI. Dead cells from GI, microorganisms, bugs, enzymes

Metabolite

Substance/by-product that comes from metabolism

GI Tract

A tube which allows nutrients to be stored, digested, absorbed and excreted

Purpose of digestion

1) break down particle size of feedstuff. 2) increase surface area. 3) increase solubility to prepare for absorption

Mechanical digestion

When feedstuff comes in the mouth. Mastication

Chemical digestion

Only Hydrochloric acid secreted and denatures - not nutrient specific

Enzymatic digestion

Causes an action - catalyst. Nutrient specific

Microbial digestion

Bugs, microbes. 1) bacteria 2) Protozoa 3) fungi.

Lives off of nutrients and turns them into by-products

Physical digestion

Movement/churning of GI tract (muscle contractions). Mixing

Diffusion

Absorption: Movement of a nutrient across GI until reach an equal equilibrium

Active Transport

Absorption: Movement of nutrient against concentration gradient. Requires energy

Passive Transport

Absorption: Flows down the concentration gradient. No energy

Phagocytosis

Absorption: "Cellular eating". Bringing in solid, selective* can sort out in-wanted

Pinocytosis

Absorption: "cellular drinking". Non-selective. (A bunch of debri will come in w that nutrient)

Definition of Absorption

Uptake of small nutrient molecules across the cells and walls of GI tract and into blood and lymph system

Blood and lymph system

What are the two primary transporters of nutrients?

Carnivore, herbivore, and omnivore

Classification of animals based on diet:

Ruminants/polygastrics & Non-Ruminants/monogastric

Classification of animals based on GI tract:

Undigested feed residues & Metabolic fecal nitrogen (can also be unabsorbed nutrients)

What makes feces?

1) brings in/apprehends 2) mechanical digestion/mastication 3) physical digestion/mixing

Functions of mouth:

Teeth

Mechanical form of digestion of the mouth

Parotid, submaxillary, & sublingual

The 3 salivary glands:

When initiated by nerves and hormones

What causes salivation?

Water, inorganic minerals, and organic compounds

Composition of saliva:

Water

Largest constituent of saliva. #1 carrier of compounds. Moistens mouth/helps form Bolus

Inorganic Minerals

Saliva: (ex. K, Ph, Na, Ca, Mg) Act as buffers, raises Ph. Acidic to neutrals (PH to 6.5)

Organic Compounds

Saliva: Urea (waste product from protein metabolism) nutrients, AA, mucal proteins. Amylase

Salivary Amylase

Enzyme secrete into mouth. Only in non-ruminants

Amylase

Carbohydrate digester. Only functional in high ph (6-6.5).

Insignificant

Digesting time in salivary amylase is:

Ruminants

Salivary amylase is not present in...

Nasal labial amylase

What kind of amylase does ruminants produce?

Esophagus

A tube made up of striated and smooth muscle tissue

Striated muscle characteristics

Own nerve fiber. All or none contractions. Ruminants have this all the way through

Smooth muscle characteristics

Doesn't have own nerve fiber. Independent until told what to do from adjacent muscle "domino effect"

Only striated

What muscle(s) does ruminants have in their esophagus?

Striated to smooth

What muscle(s) does monogastrics have in their esophagus?

Rumination

Bringing up Digesta to re-chew

Esophageal, cardiac, fundic, and pyloric

The regions of the stomache:

Esophageal Region

Stomach: no glands or secretions

Cardiac Region

Stomach: cells produce mucous

Fundic Region

Stomach: contains body chief cells(proteolytic enzymes), neck chief cells(mucous secreting), and parietal cells(HCL).

Pyloric Region

Stomach: has body chief cells(proteolytic enzymes) and neck chief cells(mucous)

Body Chief Cells

These cells produce proteolytic enzymes (found in fundic & pyloric)

Neck Chief Cells

Mucous secreting cells (similar to those in cardiac) (found in fundic and pyloric)

Parietal Cells

Produce/secrete Hydrochloric acid (found in fundic)

Serosa, muscularis, submucosa, mucosa

Tissue layers of the stomach from outside --> in

Serosa

Tissues of stomach: outermost, has CT

Muscularis

Tissues of stomach: 2nd to outermost. muscular layer, 3 different layers/directions, smooth muscle. Outer longitudinal(length), Middle Circular(around), Internal Oblique(diagonally)

Submucosa

Tissues of stomach: under muscularis 3rd from outside. CT, shape/form. Blood vessels, lymph vessels, nerves, and glands

Mucosa

Tissues of stomach: innermost, shiny, slick, thin layer of CT w/ thick mucous, wrinkled, contact w/ nutrients

Proteolytic Enzyme

Digesta proteins to amino acids.

Produced in fundic and pyloric, activated by HCL, Pepsinogen-inactive, pepsin- active

Proteolytic enzyme in the stomach:

Pepsin

________ will only contribute to about 20% of digesting all of digested proteins that were digested enzymatically

Reticulum "honeycomb"

Compartments: 1st and front compartment, microbial digestion, hardware disease, inner lining=honeycomb

Rumen "the paunch/vat"

Compartments: largest, "the fermentation vat", microbial digestion, inner lining=low profile carpet bc the little finger like "papillae"

"Rumenular-reticulum area", Digesta moves freely between the 2, "big room w 2 cubicles"

The reticulum & rumen:

Omasum "book pages"

Compartments: microbial digestion. firm bc compacted Digesta, drying, storing, holding. Inner lining= flaps of tissue that interlock-filter for solids. Moisture getting absorbed. Blind pouch(same entrance/exit)

Abomasum "true stomache"

Compartments: last of compartments, same regions, layers, secretions as stomache in mono., Chemical digestion(HCL)=ph 2.5

1) abomasum secretes lysozymes (Digests the exoskeleton of Protozoa & bacteria, allows to get in microorganisms) 2) abomasum- "rennin" in young ruminants, breaks down/digests milk.

Differences between abomasum "true stomach" and monogastric stomach:

Microbial - Protozoa & Bacteria

For a ruminant to survive they must have this type of digestion. If they don't have this, they will not digest.

The "bugs" eat the digest and convert it to feed the animal (by-products)

How does microbial digestion work?

PH 5.5-6.5 or 7. Anything lower than 5.5 is acidic and they will die

The microorganisms in microbial digestion are VERY sensitive to PH, what is their range to survive?

Lactic Acidosis

What is it called when we put a ruminant on a grain diet too fast and the PH drops, and the microorganisms die?

21 days

How many days does it take to convert a grass fed ruminant to a grain fed?

Right side

What side of the ruminant can you see all 4 compartments?

Rumen

On the left side of the ruminant, what compartment do you see?

Young calf has "esophageal" omasal grove- diverts liquid diet from esophagus to abomusum (esophagus to omasum, splashes out of omasum to abomasum). Not permanent, only there when calf is suckling.

Young Ruminant Vs. Adult Ruminant:

Rumination

The process of bringing up semi-digested feedstuff. (the 4-Rs)

Regurgitate

Controlled vomiting (b/c striated muscle), bringing up semi-digested feedstuff

Regurgitate, Re-chew, Re-salivate, & re-swallow

The 4-Rs in rumination:

By-Pass Protein

Protein and(or) amino acids that have not been digested by the micro-organism (by-passes microbial digestion) and are digested enzymatically in abomasum or small intestine. "Escape protein"

Microbial Protein

Protein and(or) Amino Acids that have been digested by the micro-organism

Eructation

Belching to release methane gas (CH4)-(highly produced in starch products from grains)

Methane gas (CH4)

Increase of grain = increase of what gas?

Ruminal Tymphany

Build up of methane gas (bloat). Can cause death (fixiation-can't breathe)

Ionophores

Non-nutritive feed additive to increase feed efficiency. Changes the by-products to produce less methane CH4.

Probiotics

Non-nutritive feed additive to add micro-organisms to GI tract. Helps ensure we don't kill the gut & maintain microbial population

Essential Amino Acids

Amino Acids that are needed by the body for normal function and/or most must be supplied by the diet because they cannot be synthesized by body at high enough levels to meet requirements.

Non-Essential Amino Acids

Amino Acids that are not needed by the body for normal function or synthesized by the body at high enough levels to meet requirements

150 L - continual saliva process

About how much saliva is produced by a ruminant - cow?

1) Fiber Digesters. 2) Synthesize B-Complex Vitamins and K. 3) Utilize simple forms of Nitrogen Urea or Ammonia

What are the advantages of Microbial Fermentation/Digestion?

Urea

NH3 + CO2 =

Ammonia

Direct NH3 =

1) Takes necessary N for survival. 2) Excess ammonia to build amino acids (microbial protein). 3) Excess absorbed into blood

What do the microbes do with Urea and/or Ammonia?

1) Fermentation expels approx. 6% of consumed energy as methane gas. 2) Most proteins and AA are partially degraded and resynthesized as microbial protein (lowers values).

Disadvantages of Microbial Fermentation/Digestion:

Volatile Fatty Acids (VFAs), CO2, Hydrogen, Methane gas, Heat of fermentation, lactic acid, & microbial protein

What are the by-products of microbial fermentation? (7)

250-500 L a day. About 6-10% energy loss

When a ruminant is fed a high grain diet, about how much methane is produced a day?

Duodenum

Small intestine: function: Has 2 secretions (Bile & Pancreatic) that aids in digestion. (will be absorption after digestion in latter section)

- know its this because you can usually see ducts to it