Nutrition of Protozoa

• Nutrition of parasitic protozoa usually occurs by pinocytosis or phagocytosis, depending on whether tiny droplets of fluids or small objects of macro molecular dimension are taken up into cell.
• After ingestion, food material reaches food vacuoles where they are fused with lysosomes and digestion occurs.
• In case of amoeba, food materials are engulfed by pseudopodia. In case of B. coli, there is special structure called cytosome. They act as mouth and take food material through cytosome.
• In case of Apicomplexa or sporozoan protozoa, there is special opening toward the side of anterior part of body known as micropore or micropyle through which food materials are taken.

Types of nutrition

• Broadly, two main types of nutrition are seen.

a. Holozoic nutrition

• In this case, ready made food or food derived from host are taken.
• Seen in case of parasitic and commercial protozoa.

b. Holophytic nutrition

• In this case, food is synthesized with help of chlorophylls carried on chromatophore in sunlight.
• Holozoic nutrition is divided into different types:

1. Saprozoic nutrition: Absorbed nutrient through body wall, are utilized directly by the organism.
2. Coprozoic nutrition: Protozoa takes organic food from the faeces.
3. Parasitic nutrition: This is found only in protozoan parasites.