Lecture 13 - Avian and Hindgut Digestive Systems

Question 1

How is the Avian Digestive System Different from other systems?

Answer 1

• birds don’t have teeth
• have poorly developed salivary glands (traces of salivary amylase, minimal carbohydrate digestion before small intestine)

Question 2

What is the crop?

Answer 2

The holding site for ingested feed

• created crop milk
• in birds that eat high fiber diets : microbial digestion

Question 3

How is chemical and mechanical digestion separated in birds?

Answer 3

It is separated into the proventriculus and the ventriculus

Question 4

What is the ventriculus?

Answer 4

Area specialized on mechanical digestion

• thick, muscular wall: physical reduction of particle size (muscular contraction)
• no enzymes secreted (chemical digestion here is a product of gastric secretions from the proventriculus

Question 5

Compare pancreatic enzymes in the avian digestive system

Answer 5

• they are released into the duodenum similar to other nonruminants
• no lactase

Question 6

What is the function of the small intestine?

Answer 6

Major site of absorption

- relatively faster passage relate than other nonruminants

Question 7

Describe the rate of passage from the small intestine

Answer 7

Digesta passes to the paired cecum

• microbial fermentation
• no substantial contribution to the bird nutrient needs

Question 8

What is the function of the ceca?

Answer 8

Water absorption, synthesis of water soluble vitamins, vitamin K
(Very limited vitamin absorption)

Question 9

How are hindgut fermenters different from other systems?

Answer 9

Most microbial fermentation in large intestine

Question 10

The stomach and small intestine functions in hindgut fermenters
And horse exceptions

Answer 10

Similar functions to other nonruminants

• Exception of the horse
  1) limited stomach muscular contractility which leads to stratification of ingesta
  2) no gallbladder; continuous release of bile from liver to duodenum