Digestion: is a biochemical process in which complex food constituents are converted to simpler compounds with the helps of enzymes secreted by digestive tract of animals. e.g starch is digested into glucose.
Fermentation: is a complex microbial process in which complex food constituents are broken down to simpler fermentation products with the help of microbes. e.g starch into volatile fatty acids.
Microbes: are tiny microscopic unicellular organisms like bacteria and protozoa that are present in large intestine and helps in fermentation of food ingredients.
Absorption: is movement of products of digestion (like glucose, amino acids, and fatty acids) from lumen of G1 tract to the blood.
Assimilation: is the incorporation of absorbed nutrients into the tissue cells for various functions. e.g. conversion of glucose to glycogen in liver & muscles, synthesis of proteins from amino acids.
Digestive System: includes a series of organs of the body, which participate in the ingestion, digestion, absorption and excretion of food. It is also referred as gastro-intestinal tract (GI tract).