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MODULE #: 4�DIGESTIVE SYSTEM

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MOUTH

Beak
No teeth
Uses tongue to push food to the back of the mouth
Contains salivary glands

Saliva with enzymes

Some species (sparrows) have amylase
Other species (chickens and turkeys) do NOT amylase

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CLEFT PALATE

The reason chickens can’t swallow:

Chickens have a cleft palate

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ESOPHAGUS: Tube that connects the mouth to the rest of the digestive tract; secretes mucus to lubricate
CROP: Used to store feed; secretes mucus

ESOPHAGUS

CROP

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CROP

Located at the base of the neck
Used to store food
Mixes feed with water birds drink

TRACHEA

ESOPHAGUS

CROP

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PROVENTRICULUS

Also known as the true stomach

Secretes hydrochloric acid (HCl)
Secretes pepsin (proteolytic enzyme important in protein digestion)

PROVENTRICULUS

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GIZZARD

Two pairs of smooth muscles
Contains grit or stones
Grinds the food

Acts as the bird’s teeth

PROVENTRICULUS

GIZZARD

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DUODENUM

Pancreas in the center

Secretes pancreatic juice with digestive enzymes

Receives bile

Produced by the liver
Stored in the gall bladder
Important in fat digestion

DUODENUM

PANCREAS

LIVER

GALL

BLADDER

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FUNCTIONS OF THE PANCREAS

Produce pancreatic juice

Proteolytic enzymes for protein digestion
Amylase for starch digestion
Lipase for fat digestion

Insulin production

For regulation of blood sugar levels

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FUNCTIONS OF BILE

Acts as a detergent, emulsifies fat
Neutralizes the pH of the digesta

Digesta from proventriculus has low pH because of hydrochloric acid
Most of the enzymes in the small intestine need to have a neutral pH

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LOWER SMALL INTESTINE

Produces many enzymes for digestion of proteins and carbohydrates
Does not produce lactase which is needed to digest lactose, a sugar in milk

Should not feed milk products with a lot of lactose to birds since it can cause diarrhea

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CECUM

Contain microflora that can ferment undigested material that reaches them
Very short colon following ceca so little opportunity for absorption of anything produced in the ceca

Most birds cannot handle high levels of dietary fiber

CECUM

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LARGE INTESTINE

Also called the RECTUM
Additional absorption of water takes place

CECUM

LARGE

INTESTINE

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CLOACA

The cloaca is where the digestive tract, the reproductive tract and urinary tract end up
Important for absorbing any remaining moisture

DIGESTIVE

TRACT

REPRODUCTIVE

TRACT

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Two types of droppings:

Regular
Cecal

Chickens expel two kinds of poop. Regular droppings consist of a blob of brown or grayish or greenish digestive waste topped with white urates, the chicken’s equivalent of urine.

Cecal droppings are more pasty or foamy and lack the white urate cap.

Chickens should excrete both kinds of droppings.

It is important to look at the droppings to be alert for trouble signs. Look for tinges of blood, new odors, or exceedingly runny droppings. Runny poop can occur when chickens drink a lot of water in hot weather or eat juicy treats such as watermelon. Color changes, too, might not be cause for concern. If the poop looks suddenly different, the feed may have changed. Reddish poop might be beets that have been fed.

If eat a lot of greens and water, some of the droppings might be wet or loose.

The first droppings of the day can be quite large. A broody hen that seldom leaves the nest will also have extremely large droppings.

From time to time, there might be reddish strings in droppings. If inert, they may be old intestinal lining being shed. If the droppings look like they have coffee grinds in them, they may have internal bleeding.

Droppings that having moving worms, are consistently runny or bloody, or droppings that stick to the vent are cause for concern.