VPB 321: Animal Biotechnology (2+1)

Application of recombinant DNA technology to rumen organisms

APPLICATION OF RECOMBINANT DNA TECHNOLOGY TO RUMEN ORGANISM

• The type of alteration that is most desirable is
• an increased ability by rumen organisms to digest coarse plant fibre,
• by the increased production of cellulolytic and xylanolytic enzymes.
• Succinogenes are cellulolytic and are unable to digest xylan, while B. rnminicola has only xylanolytic activity. By giving the dominant populations of bacteria with digestive capability for multiple cell wall constituents, it may be possible to enhance fibre digestion by a sort of mixed populations that occur naturally.
• Many bacterial genes have inducible promoters and such switches may be useful for the timed induction of nutrient synthesis, antibiotic production, anti-helminthic synthesis, etc. The initial step in this process is to identify inducible genes in the ruminal anaerobes and isolate promoter sequences responsible for control functions.
• Gene libraries have been constructed and used to isolate the genes for cellulose enzymes which can be expressed as active molecules in the E. coli host cells.
• The genetic manipulation of rumen microorganisms by altering the inherited characteristic is the most powerful potential tool for enhancing the rate and extent of digestion of fibrous feeds within the rumen.
• Its success depends on the identification of the specific genetic information, the development of appropriate genetic techniques and creation of new organisms with high probability of survival in the harsh environment of the rumen of animals fed on highly fibrous feeds.