Organic Value Recovery Solutions LLC Antimicrobial Peptides from Lower Animals? G.L. Newton, Animal& Dairy Science Department University of Georgia, Tifton Campus Potential Antibacterial Properties of Fly Larvae There is considerable evidence that various fly larvae reduce bacterial activity where they feed. The larvae of several  fly species have been shown to be capable of digesting live bacteria, and inducible antimicrobial peptides have been  identified in many species (Hoffman and Hetru, 1992; Natori, 1995; Hultmark, 1993; Bulet et al, 1999; Sherman et al,  2000; Reddy et al, 2004).   BPharm et al. (1996) discusses several mechanisms that may account for the bacteria-free,  antiseptic conditions of wounds occupied with surgical maggots, where conventional medical treatments have failed.   The existence of antimicrobial compounds in black soldier fly larvae has not been studied, but two observations  suggest their presence.  A preliminary test showed a greater than 100 fold reduction of inoculated pathogenic E. coli in  media occupied by black soldier fly larvae compared to media without larvae.  An attempt to preserve chopped black  soldier fly larvae by ensiling (mixing them with ground corn and whey, inoculating with lactic acid bacteria, followed  by anaerobic storage) failed to produce an ensiled product.  Fermentation was strongly inhibited by even the lowest  larvae addition (1% of dry matter).  Although pH was higher than the controls, the material did not putrefy and  ammonia production was lower than in control mixtures with no black soldier fly larvae, which did ferment.  Studies to  more critically evaluate the microbiology of larvae culture are needed.  Potential for Collecting Natural Antibacterial Products From Lower Animals Just as mammals produce antibodies in response to many bacterial and viral infections, lower forms of animals also  possess chemical defenses to microbes, although the molecules may often be simpler than mammalian antibodies.   These may take the form of antibacterial or bacteriostatic proteins or peptides which are always present in a particular  animal species which most generally competes with specific microbes for a food source, or requires that a specific  micro flora be maintained in its digestive tract.  In addition to these “always present” bioactive molecules, lower  animals often also have an arsenal of inducible antibacterial or bacteriostatic peptides which are produced only in the  presence of insult.  While this subject has received relatively little study, it appears that some (an unknown proportion)  of these inducible peptides are effective against families of microbes rather than a specific microbial species.  Mass rearing of some lower animals which produce bioactive proteins and/or peptides is possible using inexpensive  substrates (waste products).  It may be possible to induce antibacterial peptides in these organisms which would be  active against mammalian pathogens without actually exposing them to the pathogen (appears to be possible for  pathogenic E. coli).  These organisms could then be processed for inclusion in feeds for domestic animals as a source  of bioactive peptides.  These feed products could potentially serve to protect the domestic animals from microbial  insult or infection or serve as a source of bioactive peptides somewhat analogous to the inclusion of dried plasma in  weanling pig diets.  Alternately, once identified, specific peptides could be produced in the laboratory for use against  specific target microbes in a variety of situations.    Literature Cited Bulet, P., Hetru, C., Dimarcq, J. L., and Hoffmann, D. 1999. Antimicrobial peptides in insects; structure and function. Dev. Comput. Immunol. 23:329-344. BPharm, S. T., M. Jones, S. Shutter and S. Jones.  1996.  Using larvae in modern wound management. J. Wound Care. 5: 60-69. Hoffmann, J.A. and C. Hetru. 1992. Insect defensins: Inducible antimicrobial peptides. Immunology Today, 13 (10):411-415. Hultmark, D. 1993. Immune reactions in Drosophila and other insects: A model of innate immunity. Trends Genet. 9:178-183. Natori, S. 1995. Antimicrobial proteins of insects and their clinical application. Nippon Rinsho. 5:1297-1304. Reddy, K.V.R., R.D. Yedery, and C. Aranha. 2004. Antimicrobial peptides: premises and promises. Internatl. J. Antimicrobial Agents. 24:536-547. Sherman, R.A., M.J.R. Hall, S. Thomas. 2000. Medicinal maggots: An ancient remedy for some contemporary afflictions. Ann. Rev. Entomol. 45:55-81. © Organic Value Recovery Solutions 2010 © Organic Value Recovery Solutions 2010