The main methods used, or under investigation, for production of rumen gene engineering bacteria are:gene deletion technique, gene recombination technique and the application of promotor.

Molecular pharming is to use plant cells as bioreactors to produce various valuable proteins or peptides at large scales for pharmaceutical and nutritional USES.

Therefore, novel delivery method has become a hot topic, mainly including improving delivery systems, developing new recombinant insulin, and changing the route of administration.