Digestion in ruminants and rodents

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