Biotechnology and Bioinformatics (1+1)

6.4.5. Prebiotics

The concept of prebiotics in feed is fairly recent. Prebiotics are basically feed for probiotics where they are resistant to attack by endogenous enzymes and hence reach the site for proliferation of gut microflora.

Some of the prebiotics, which are currently used in animal feed, are

• Mannan-oligosaccharides (MOS),
• fructo-oligosaccharide and
• mixed oligo-dextran.

Mannan-oligosaccharides are mainly obtained from cell walls of yeasts. Other sources of MOS are copra or palm kernel meal. MOS interferes with the colonization of the pathogens. Cell surface carbohydrates are primarily responsible for cell recognition. Bacteria have lectins (glyco protein ) on the cell surface that recognize specific sugars and allow the cell to attach to that sugar. Binding of Salmonella, E.coli and Vibriosp. is shown to be mediated by a mannose specific lectin like substance present on the bacterial cell surface.

Similarly fructo-oligosaccharides from chicory have been used as prebiotics to competitively exclude pathogenic bacteria. The pH of the lumen gets reduced thus preventing the entry of pathogenic bacteria.

The concept of using prebiotics has not yet been accepted but the advantages of prebiotics are that it can stand high pelletizing temperatures in the feed and also have a long shelf life.