non-ruminant-digestion

What are the four stages of digestion in non-ruminants?

Chewing → Digestion → Absorption → Excretion

Name the three types of non-ruminant digestive systems.

1. Simple stomach (e.g., pigs, dogs, cats)

2. Hindgut fermenters (e.g., horses)

3. Avian (e.g., chickens)

What are the three forces that act on food in the GIT?

Mechanical, Chemical, Enzymatic

What are the three regions of the small intestine?

Duodenum, Jejunum, Ileum

What enzyme activates trypsinogen to trypsin?

Enterokinase (enteropeptidase)

What is the function of bile?

Emulsifies fat, increasing surface area for lipase action

Where is bile made and where is it stored?

Made in the liver, stored in the gallbladder

Which enzymes break down disaccharides in the small intestine?

• Maltase → glucose

• Sucrase → glucose + fructose

• Lactase → glucose + galactose

What is the role of the cecum in non-ruminants like horses?

Microbial fermentation of fiber → produces VFAs, B vitamins, some protein

What are the two stomachs of poultry and their functions?

• Proventriculus: glandular, secretes acid and enzymes

• Gizzard: muscular, grinds feed with grit

What are the three pancreatic enzymes that digest proteins?

• Trypsinogen

• Chymotrypsinogen

• Carboxypeptidase

Which enzyme is inactive in the stomach but starts carbohydrate digestion in the mouth?

Salivary amylase

What enzyme do neonates rely on for lipid digestion?

Lingual lipase

What are zymogens, and how are they activated?

Inactive enzyme precursors activated by hydrolysis (e.g., pepsinogen → pepsin)

What hormone regulates gastric juice secretion?

Gastrin

What are the three absorption mechanisms in the small intestine?

• Simple diffusion

• Active transport (requires ATP)

• Protein-mediated transport (no ATP)

What are the end products of nucleic acid digestion?

Pentoses, phosphate, nitrogenous bases (via nucleosidase and phosphatase)

What vein drains nutrients from the small intestine to the liver?

The portal vein

In hindgut fermenters, what two products from microbial fermentation are absorbed?

VFAs and water-soluble vitamins

What structures in avian species aid in mechanical and chemical digestion?

• Gizzard = mechanical digestion (grinding with grit)

• Proventriculus = chemical digestion (acid and enzymes)

In hindgut fermenters like horses, what structure is the main site of microbial fermentation?

Cecum and large colon

What can volatile fatty acids (VFAs) provide in horses?

Over 70% of their daily energy needs

What is the primary function of the large intestine in non-ruminants?

• Water absorption

• Waste storage

• Some fiber digestion

• Sodium chloride absorption

What are the three parts of the large intestine?

Cecum, Large Colon, Small Colon

What part of the avian digestive tract stores and moistens feed?

The crop

What is the gizzard and what does it do?

Muscular stomach that grinds feed with grit (sand/stones)

What are the ceca in poultry used for?

Microbial fermentation of fiber and some starch; VFA and B-vitamin production

Why is feed particle size important in poultry?

It affects digestion efficiency; finely ground feed improves nutrient absorption

What is the cloaca in birds?

Common chamber for digestive, urinary, and reproductive tracts

Which animals have no teeth, few salivary glands, and no swallowing reflex?

Birds (e.g., chickens)

What are the three forces acting on food in the GIT during digestion?

1. Mechanical – chewing

2. Chemical – acid (HCl)

3. Enzymatic – enzymes like pepsin

What two enzymes are involved in mouth digestion, and which is inactive in the stomach?

• Salivary amylase (inactive in stomach) – digests carbs

• Lingual lipase (active in stomach) – digests lipids

What do neonates rely on for lipid digestion?

Lingual lipase

What enzyme is absent in horses and humans but present in neonates of other species for milk digestion?

Rennin

What are zymogens, and how are they activated?

• Inactive enzyme precursors

• Activated by hydrolysis of amino acid residue

List the components of gastric juice.

• Pepsin

• Rennin

• Gastric lipase

• HCl

• Mucus

What does enterokinase (enteropeptidase) do?

Converts trypsinogen → trypsin (activates other proteolytic enzymes)

What enzyme is required to activate trypsinogen from the pancreas?

Enterokinase

Which enzymes digest nucleic acids, and what are the end products?

• Nucleosidase and phosphatase

• Products: pentoses, phosphates, nitrogenous bases

Which avian digestive organ has no sphincter separating it from the intestine?

The gizzard