digestion in ruminants and rodents
TRANSCRIPT
Digestion in ruminants
and rodents
Vertebrates and human do not produce cellulase to digest plant cellulose.
Enzyme cellulase hydrolyses cellulose to complex sugars and glucose.
Cellulase-secreting microorganism to digest cellulose for them.
What is the meaning of Ruminants?
??
Has a four-chamber (compartment) stomach.
three chambers before the true stomach.
Example: cows, sheep, goats, giraffes and deer.
Mouth oesophagus stomach (4
chamber)
large intestine Small intestine
a) Rumen- the first and the largest chamber - function as fermentation chamber -contain a lot of symbiotic
microorganismb) Reticulum- has a “honeycomb” wall
- house a lot of symbiotic microorganism
-open to the omasumc) Omasum- many folds to grind food
- a lot of water is absorbed hered) Abomasum - “ true” stomach
- secretes pepsin and HCl to digest food.
Crop grass, mixes the ground grass with saliva before enter into the rumen.
In rumen, semi-ground grass ferments with symbiotic microorganism- secreting cellulase
Fatty acid and glucose produced are absorbed through the wall of rumen.
Fermented grass moves from rumen to the reticulum—formed into balls(called cud).
From the reticulum, cud is regurgitated into its mouth to be re-chewed
Cud is finely ground--- re-swallowed and goes into omasum.
In omasum, much water is absorbed from the cud before passed on to the abomasom.
In abomasom, HCl and protease secreted to digest the proteins of the grass and microorganism.
Chyme enter the small intestine---rest of digestion continues
Absorption takes place on the lower part of small intestine
In large intestine, water and some vitamins and mineral are absorbed.
Faces expelled from the anus
It have large incisors adapted for gnawing or
nibbling.
Have a simple, one-chamber stomach structure.
Example: humans, cats, dogs, rabbits and rodents( rats, squirrels).
Oral cavity Salivary glands Pharynx
small intestine stomach Oesophagus
Caecum Large intestine
Accessory organs- pancreas and liver- secretes digestive juices.
Rodents are mostly herbivorous or omnivorous.
Have large caecum containing symbiotic bacteria.
After ingested food in stomach has softened, it passes down the small intestine into the caecum.
In caecum, symbiotic bacteria digest the cellulose---release nutrients.
Nutrient absorbed in small intestine Re-eat their own faeces to absorb more
nutrients from the faeces the second time it goes through the small intestine again.
Faeces going out from the anus
SimilaritiesAll do not secrete cellulase to digest
selluloseAll depend fully on symbiotic
microorganism
Differences????
Aspect compared/ Organism
Ruminant Rodent
Stomach 4 chamber Single stomach chamber
Comparative amount of cellulose eaten
All grass •All plant matter( herbivores)•A large portion ( omnivores)
Digestion of cellulose
By symbiotic bacteria and protozoa in the rumen, reticulum compartments, and caecum
By symbiotic bacteria and protozoa in the caecum.
Chew cud Yes No
Re-ingestion of faeces
No Yes
Regurgitate Regurgitate food Do not regurgitate food