Advance Animal Nutrition Final

Mixes and breaks down food

Segmentation

Large contractions in the colon moving fecal matter

Mass movements

Wave-like contractions that propel food

Peristalsis

Clears residual food and debris

Migrating Motor Complex

By comparison, which of the following would have the higher slow wave frequency?

Duodenum

Explain how the MMC patterns differ between carnivores and herbivores

Carnivores have a strong, regular MMC during fasting with a prominent Phase III “housekeeper wave” that clears the GI tract between meals. Herbivores have a reduced or modified MMC because they eat continuously; their motility is dominated by ongoing fermentation and mixing, so distinct MMC cycles are less pronounced.

T/F: The stomach can be divided into two sections based on motility function. The orad portion is made up of the distal body and antrum

False

The colon displays three types of contractile movements. They are Stationary, Haustral, ______ and _______

Anti-peristaltic and Peristaltic

T/F: the normal stimulus for defecation is the distention of the terminal colon and rectum

True

Describe the bi-phasic nature of contraction in the ruminant

• The first contraction is weaker and mixes ingesta, moving smaller particles toward the omasum

• The second contraction is stronger and helps move gas to the esophagus for belching and can also initiate rumination.

The thin muscle coat that contracts to expand the radius of the digestive tract is the _____ muscle.

Longitudunal

T/F: The enteric Nervous System consists of the Parasympathetic and Sympathetic systems

False

Thick muscle coat that contracts to reduce the size of the lumen is the _____ muscle.

Circular

In the esophagus, this occurs if the esophagus fails to empty

Secondary peristalsis

Which system (Sympathetic or Parasympathetic) inhibits slow wave patterns?

Sympathetic

T/F: Gastric emptying speeds are greater for solid that liquids

False

These are responsible for the slow wave phenomenon and act as pacemakers.

Interstitial Cells of Cajal

By comparison, which of the following would have the higher slow wave frequency?

Small intestine

Cavital peptidase

Pepsin

Cavital esterase

Pancreatic Lipase

Intestinal glycosidase

Sucrases

Cavital glycosidase

Amylase

_____ is an example of a secretion that lubricates and protects

Saliva

______ is an example of secretion that alters pH

HCL

_____ are an example of a secretion that does the digestion

Enzymes

______ is an example of a secretion that assists with digestion

Bile

T/F: In non-ruminants, digestive enzymes attack feed prior to microbial fermentation in the large intestine.

True

Describe the importance of Renin in a young ruminant

Renin coagulates milk and allows a controlled flow of the “curd”. This improves digestion and absorption of milk.

T/F: Pepsin is inactive at pH above 3.5

False

If exogenous enzymes are given to dairy cattle, and an observed result is an improves NDF digestibility, what type of enzyme would ypu draw a conclusion that they are providing?

Cellulolytic

Esterase is to lipids, as peptidase is to proteins, as ______ is to carbohydrates.

glycosidase

T/F: Exogenous enzymes have the ability to assist the endogenous digestive enzymes in breaking down macromolecules to release nutrients. The result of this could be an observation of decreased digestibility

False

What cells are Motilin secreted from?

M-Cells

What cells are Gastrin secreted from?

G-cells

What cells are somatostatin secreted from?

D-cells

______ is produced by the stomach in response to dietary protein and gastric distention; causes the GIT to produce and release acid, but is eventually inhibited by the increasing acidity of the GIT

Gastrin

Growth Hormone Inhibiting Hormone is also known as _____

Somatostatin

The Gastrin receptor also binds this hormone

CCK

CCK causes the GIT and associated organs to do things that enhance the digestion of fats and proteins. Discuss at least two of these.

• CCK stimulates pancreatic enzyme secretion which improves breakdown of fats and proteins.

• CCK causes gallbladder contraction and bile release→ Bile emulsifies fats, increasing surface are for digestion.

_____ stimulates motility during the interdigestive phase.

Motilin

______ inhibits digestive and pancreatic hormones

Somatostatin

CCK_A receptor is predominantly found in the pancreas, and CCK_B is found in the brain and ______?

Stomach

______ is produced by the small intestine in response to acidic conditions, it stimulates production and release of bicarbonate which increases the pH of the chyme.

Secretin

This hormone is structurally similar to Glucagon, VIP, and GIP

Secretin

______ stimulated by presence of fats, glucose, and bile in the SI and will inhibit HCL production

GIP

T/F: Somatostatin is found in two biologically active forms, SS-14 and SS-28

True

GIT=?

hollow tube from mouth→ anus

Major parts of the GIT

• Mouth

• esophagus

• stomach

• Small intestine (Duodenum, jejunum, ileum)

• Large intestine (cecum, colon, rectum)

What are the three main roles of the GIT

• Digestion

• Absorption

• Elimination of waste

What are the 4 types of digestion?

• Mechanical

• Chemical

• Enzymatic

• Microbial

Mechanical digestion

Chewing, contractions

Chemical digestion

HCL, bile

Enzymatic digestion

digestive enzymes

Microbial digestion

microbes break nutrients

Where does absorption occur?

Small intestine

Two structures used for absorption

Villi and Enterocytes

Why are villi important?

Increase the surface area

What does protein get absorbed as?

Amino acids, peptides

What do carbs get absorbed as?

Simple sugars

What does fiber get absorbed as?

VFAs

What does fat get absorbed as?

fatty acids and glycerol

What is the difference between peristalsis and antiperistalsis?

• Peristalsis: moves forward through the GIT

• Anti-peristalsis: moves food backward (vomiting, rumination)

What are the three function of the stomach

• Storage

• Mixing

• Secretion of enzymes and acid

In ruminants what are the 4 compartments of the stomach?

• Rumen

• Reticulum

• Omasum

• Abomasum

Rumen

Fermentation and microbes

Reticulum

Regurgitation and sorting

Omasum

water absorption

Abomasum

True stomach, enzymes

What do microbes do during digestion?

Break down feed

Where are microbes found?

• Rumen

• Cecum/colon

What is the role of the small intestine?

Main site of digestion and absorption

What are the roles of the large intestine?

• Water absorption

• Microbial fermentation

• Feces formation

What does the pancreas do?

Produces enzymes and hormones

What does the liver/gallbladder do?

bile production/storage

What are the two types of digestive systems

• foregut fermenters (ruminants)

• Hindgut fermenters (horse)

Ruminant vs Non-ruminant

• Ruminant: has rumen

• Non ruminant: does not have a rumen

Concentrate Selectors

• low fiber digestion

• Example: Giraffe

Grass/Roughage eaters

• High fiber digestion

• Cattle

Intermediate feeders

• High fiber and low fiber digestion

• Goats

Rumen bacteria are?

Obligate anaerobes and Facultative anaerobes

Ammonia is produced by bacteria through this process:

deamination of amino acids

T/F: Ionophores are restricted under the VFD

False

T/F: In general ammonia is more important than amino acids for bacteria which digest simple sugars rather than complex carbohydrates

False

Which of the following would be considered a bacteria that produces both xylanases and proteases?

Prevotella ruminicola

Explain two positive roles/contributions Protozoa provided to the rumen ecosystem

Store reserved carbohydrates and stabilize fermentation.

T/F: In high concentration diets, feeding ionophores results in reduced feed intake and no change in ADG

True

What do intermediate acid-utilizing bacteria do?

Convert fermentation acids and help prevent acidosis

The three types of microbes include: ______, _______ and _______

Bacteria, Protozoa, and fungi

Why is some methane production important?

They remove H2, which allows fermentation to continue

T/F: It is estimated that there are 1,000,000,000,000,000 rumen bugs per cow

True

Normal fermentation occurs at osmolarities between

260-340 mOsm

Useful product of fermentation

VFAs

Useless product

CO2, Methane

Harmful product

ammonia

Which of the following would be considered a gram-negative fibrolytic microbe?

FIbrobacter succinogenes

T/F: The polyether compound produced from Streptomyces eurocidicus helps formulate the active ingredient in Rumensin

False

T/F: Protozoa efficiently use nitrogen sources such as urea and ammonia

False

Calculate Ruminal Digestion Rate given:

Kd= digestion rate=3.0%/hr

Kt=Disappearance rate= 6.0%/hr

6.0/3.0= 2.0

T/F: Ionophores select for gram-negative bacteria

True

Provide one name of an ionophore

Rumensin