ANS230 Lecture 26/27/28 : Comparative Nutrition- Classification, Digestion and Physiology File

What is the first organ formed in early embryonic stages of development?

GI Tract

What are the two main questions to ask regarding comparative nutrition?

What do the animals need and how do they get it?

What is the difference between pre gastric and post gastric species?

Whether or not fermentation occurs before or after the stomach

When does fermentation occur on pre-gastric fermenters?

Before the stomach

When does fermentation occur on post-gastric fermenters?

After the stomach

When theres a large compartment in a GI tract, what is usually in that large compartment? What does that indicate?

Microbes; fermentation

True/False : Foregut and Pregastric are synonyms

True

If an animal is a foregut fermenter, what should we expect their diet to be made of?

Forages/Roughages

What kind of fermenters are cows?

Foregut

What kind of fermenters are horses?

Horses

What is the most important requirement for energy and nutrients in animals?

Glucose

Where do post-gastric animals get their glucose from?

Directly from the diet

Where do pe-gastric animals get their glucose from?

Proprionate; SCFA produced from microbes, serves as a precursor for glucose

What animals would we respect to rely more on microbes: animals that consumer more or less fiber?

More fiber

True/False, Microbes are in the GI Tract of all animals

True

_______ impacts microbes.

Diet

What three things do microbes impact/

• Diet selection

• Form of nutrient supply

• Animal health

What percent of energy comes from SCFA in ruminants?

70%

SCFAs are produced at ________ regions of the GI tract

different

Once again, what are the three main short chain fatty acids?

Acetate, Propionate, and Butyrate

What is the pipeline in which the SCFAs are transported?

Gut → Portal Vein → Liver → Organs

What is the main gluconeogenic for all animals

Proprionate in the Liver

What does the gut barrier do?

Keeps external pathogens in feed from coming into circulation

What SCFA aids the gut barrier?

Butyrate

What kind of fermenters have the largest gastric capacity?

Pregastric Fermenters

Do carnivores have a small or large stomach? How does this impact their nutrient density?

Small stomach, less nutrient dense diets

In the GI tract, what is the least variable component across species?

The smal intestine

What generalization can be made about small intestine length between carnivores and herbivores?

Small intestine length is shorter in carnivores

How does size of a GI tract relate to a diet?

The larger the GI tract, the more complex the diet

What do Vertebrate digestive systems consist of?

Tubular GI tract and accessory organs

In the GI tract, what two strucutres serve as the entry point for digestion?

THe mouth and pharynx

In the GI tract, what organ delivers food to the stomach?

Esophagus

In the GI tract, what organ serves as preliminary digestion?

The stomach

In the GI tract, what organ is the main site of absorption and digestion?

The small intestine

In the GI tract, what organ absorbs water and minerals?

The Large Intestine

In the GI tract, what organs expel waste?

Cloaca or rectum

What are teeth used for in most vertebrates?

Chewing or mastication

In the feed industry, what is one of the most important physical parameters for feed?

Surface Area

What is the purpose of breaking down feed?

To increase surface area

Since birds dont have teeth, where do they break up food?

In their two-chambered stomach

How do birds break up food?

The gizzard - the muscular chamber that uses ingested pebbles to pulverize food

How do teeth relate to the diets of animals?

Their dentition reflects what they’re going to eat

What is the defining feature of carnivore teeth, and how does that affect how they eat their food?

They have pointed teeth that lack flat grinding surfaces that they use to flesh and meat

What is the defining feature of herbivore teeth, and how does that affect how they eat their food?

Herbivores have large flat teeth suited for grinding the cellulose cell walls of plant tissues

What is the defining feature of omnivore teeth, and how does that affect how they eat their food?

Humans have carnivore-like teeth in the front and herbivore-like teeth in the back, they can eat in a way that combines both carnivore and herbivore eating styles

What is also generated in the mouth when chewing occurs?

Saliva

What are the three functions of saliva?

• Lubrication - Moisten Feed

• Aids swallowing

• Starch and/or Lipid Digestion

  • remember Amylase and Lipase in saliva

Is Amylase present in omnivores?

Yes

Is amylase present in carnivores?

No

What does the esophagus connect?

It connects the pharynx to the stomach

What is the movement of food (or bolus) down the esophagus called?

Peristalsis

What does the swallowing center in the brain do?

It stimulates succesive one-directional waves of contraction

What does the pyloric sphincter do?

It allows food to enter the stomach

What are the two types of mucosa?

Glandular and nonglandular

What are the three glandular regions of the stomach called?

• Cardiac

• Gastric/Fundic

• Pyloric

What do all three regions of the glandular mucosa produce a lot of?

Mucous

What does mucous do in the stomach?

It protects the lining of the stomach from acid/

What are the main cells in the stomach responsible for secreting HCl and intrinsic factors?

Parietal Cells

What is the secretion of the intrinsic factor good for?

It is critical for the absorption of Vitamin b12 in the small intestine.

What is the only source of Vitamin B12?

Fermentation/Microbes

What cells are responsible for the secretion of gastric enzyme precursors (i. e pepsinogen)?

Chief cells

What are the three exocrine cells in the stomach?

• Mucous cells

• Parietal cells

• Chief Cells

Why are exocrine cells termed the way they are?

Because everything they release is around epithelial cells and they act upon the cells

What do endocrine cells secrete?

Hormones ; somatostatin and histamine

Where are hormones released into?

Circulation