Equine Flashcards
Which part of the GI tract is modified into the fermentation chamber?
Ascending colon
What are the 3 compartments of the fermentation chamber?
Caecum
Ventral colon
Dorsal colon
Which valve separates the ventral and dorsal colon?
Pelvic flexure
How is the longitudinal muscle arranged?
Taenial bands
Why is fermentation extensive in horses compared to carnivores and ruminants?
Vast majority of non-hydrolysable CHO reaches large intestine so fermentation extensive
What are the microbial products of fermentation?
VFAs / CH4 / CO2
What is egested as a result of the large intestine being the terminal part of the GI tract?
Some VFAs and all microbial protein
What are VFAs absorbed by?
short chain fatty acid (SCFA) / HCO3- exchanger
What are the 3 methods of water absorption in the LI?
Osmotic pressure
Hydrostatic pressure
Solvent drag
How does the fermentation process differ in horses and ruminants?
Horse SI before fermentation
Ruminant SI after fermentation – easier potential for overload of hCHO
What is secreted in response to the decrease in pH due to production of VFAs?
- Pancreatic secretion containing HCO3-
- Goblet cells in large intestine secrete mucous & HCO3-
- Ileum also secretes HCO3-
How is protein fermentation adapted in horses?
- Equine hind-gut more capable of absorbing amino acids
- more amino acids absorbed by the host which helps make up for the amount lost in microbial protein
What is there a consequent net absorption of when VFAs are absorbed?
NaCl which enhances water reabsorption via osmotic pressure & solvent drag
What mustn’t be fed in excess otherwise it’ll upset the microbial balance?
hCHO - overload in the small intestine
Why is the bacterial population lower in horses compared to ruminants?
Food material passing into fermentation chamber generally contains lower levels of hCHO
- fermentation is slower
