Avian Digestion PDF
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Uploaded by RaptTriumph4417
University of Missouri
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Summary
This document provides a comprehensive overview of avian digestion, covering anatomy, physiology, and the digestive cycle. Diagrams and explanations illustrate the process, from crop function to the role of the gizzard in grinding food. Also, it includes the constant reverse peristalsis, which is crucial for absorbing water and fermenting content in the colon.
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all birds have some digestion in crop: microbial digestion salivary amylase Avian Digestion Anatomy:...
all birds have some digestion in crop: microbial digestion salivary amylase Avian Digestion Anatomy: 1. No teeth ventriculus (with grit) 2. Presence of crop in esophagus (except in owls and insectivorous birds) -do have an esophageal enlargement acid and ezyme secretion 3. Glandular stomach (proventriculus) is proximal to the muscular stomach (ventriculus; gizzard) 4. Duodenal loop and jejunum/ileum (jej/ile not Storage distinct) no difference in muscle thickness so called ileum 18 5. Paired ceca (most birds) domestic fowls 6. Short colon that empties into cloaca (combined chamber for urine and feces) 14 7. Most birds have gallbladders (not pigeon) Physiology crop has an ingesta storage Crop: function (like proximal stomach ) 1. First food eaten goes to proventriculus and remainder to crop 2. Movement from crop to proventriculus thereafter controlled by fullness of proventriculus and intestines (feedback long reflex). -Also, food can be regurgitated to feed young (crop ‘milk’ for pigeons/doves). high fat content from apocrin secretion ~ like milk Gastroduodenal cycle: 1. Thin gizzard muscles contract and 2 - 3 peristaltic -pylorus waves pass down duodenum (pyloric digesta passage)open 2. Thick gizzard muscles contract (grind) and content oral movement for more gastric digestion refluxed into proventriculus - Some predaceous birds (owls, comorants, hawks) regularly egest gastric pellets of bone and hair 3. Peristaltic wave passes from proventriculus (returns content to gizzard) 4. Regular intervals of reverse peristalsis in duodenum (every 15 min). Duodenal content is refluxed into gizzard. more gastric digestion Colonic motility: 1. Constant reverse peristalsis toward ceca -Moves urine and digesta from colon and cloaca into ceca -Functions: a. Absorption of salt & water of cecum b. Fermentation 2. Reverse peristalsis ceases immediately before defecation (whole colon contracts during defectation) no crop, ventriculus less mucular regurgitation maneuvar pancreatic and bile ducts enter at distal end of duodenal loop
