Question

How can herbivores digest cellulose?

Answer 1

Digestion is the catabolic process by which non-diffusible complex biomolecules are converted into simple biomolecules by the process of hydrolysis in the presence of digestive enzymes so that food can be absorbed easily.

Complete answer:
-Herbivores are the animals that eat only algae or plant materials, for example, cows, rabbits, deer, etc. Cellulose is present in the cell walls of plant materials such as vegetables, and bran. This constitutes roughage.
-The ruminants are the herbivores that chew the cud and they include cattle, buffaloes, goats, etc. They have a large compound stomach consisting of four chambers- rumen, reticulum, omasum and abomasum.
-All four chambers have different functions. Rumen forms the largest portion of the stomach and it has villi with a cornified surface. These villi help in breaking and churning of food. The reticulum is lined by stratified keratinized epithelium and is involved in the contraction and relaxation that helps in mixing and churning the food substance. Omasum helps in mixing and breaking down the ingested food substances while abomasum has gastric juices that help in the biochemical digestion of food.
-The chamber rumen has some symbiotic microorganisms like bacteria that help in fermentation and breakdown of cellulose.

Additional information:
The stomach serves four functions in herbivores that are storage of food, mechanical churning of food, partial digestion and regulation of the flow of food into the small intestine. Storage of food in the stomach enables the animals to take food at intervals.

Note: Roughage is not digested in the human intestine. It provides bulk to the diet for satisfying the appetite. Its bulk expands the gut and stimulates peristalsis to eliminate faeces which helps prevent constipation.