<< Return to Press Releases

Contact:

NEWLY PROPOSED MECHANISM FOR THE ACTION OF ANTIMICROBIAL GROWTH PROMOTERS (AGPs) MAY OPEN THE DOOR TO THE DEVELOPMENT OF NEW NON-ANTIBIOTIC ALTERNATIVES TO AGPs

The Proposed Mechanism — Outlined in the April Issue of Poultry Science — Turns Conventional Wisdom about AGPs on Its Head, According to the Poultry Science Association

SAVOY, IL (March 26, 2007) – The currently accepted paradigm for how in-feed antimicrobial growth promoters (AGPs) function may need to undergo radical revision, according to the author of an article in the April 2007 issue of Poultry Science. Moreover, if the alternative mechanism proposed by the author is correct, then it could help to focus research on the development of never-before-considered, non-antibiotic alternatives to AGPs, according to the Poultry Science Association (PSA), which publishes Poultry Science.

The article, an invited review by Prof. Theodoor (Theo) A. Niewold of the Catholic University of Leuven, Belgium, is titled “The Nonantibiotic Anti-Inflammatory Effect of Antimicrobial Growth Promoters, the Real Mode of Action? A Hypothesis.”

AGPs – The Accepted View and a New Proposal

The in-feed use of antibiotics in sub-therapeutic concentrations as growth promoters has been a common practice in the poultry industry (and other industries) for several decades, but a precise understanding of how AGPs work has, to date, not been determined.

The conventional wisdom has been that AGPs act by modifying the microflora (bacterial and other microbial populations) of the gastro-intestinal tract. Various mechanisms for how this takes place have been proposed, including: reducing sub-clinical infection; decreasing production of microbial products that exert toxic effects; depressing microbial competition within the chicken or other livestock species for nutrients and enhancing absorption as the gut wall is thinner.

Dr. Niewold argues that, based on the evidence, none of these suggestions is persuasive as an explanation of the mechanism of action of AGPs, and he goes on to propose an alternative model that explains the efficacy of AGPs as likely being a result of their anti-inflammatory effects: “AGPs most likely work... by inhibiting the production and excretion of catabolic mediators by intestinal inflammatory cells.” He goes on to suggest that “[c]oncomitant or subsequent changes in microflora are most likely the consequence of an altered condition of the intestinal wall,” rather than a direct result of the action of AGPs.

Potential Impact on Research and the Industry

“There is growing pressure to ban the use of AGPs in the U.S. That pressure has been building – particularly since Europe’s total ban on in-feed AGPs went into effect in January 2006. Since expectations are that the U.S. will eventually follow suit, there is an acute need to develop practical alternatives. If Professor Niewold is correct in his conclusions, then researchers can begin to target their efforts on developing alternative, non-antibiotic compounds that have anti-inflammatory effects similar to AGPs,” said Poultry Science Editor-in-Chief Dr. Colin Scanes.

About Poultry Science

Published monthly (print and online) by PSA, papers in Poultry Science focus on findings from basic (pure) scientific research, including work on breeding and genetics; production, modeling, and education; environment, well-being and behavior; immunology, health, and disease; molecular, cellular, and developmental biology; metabolism and nutrition; physiology, endocrinology, and reproduction; and processing, products, and food safety. For subscription information, see http://ps.fass.org/subscriptions/.

About PSA

The Poultry Science Association (PSA) is a global scientific society dedicated to the discovery and dissemination of knowledge generated by poultry research – knowledge that enhances human and animal health and well-being and provides for the ethical, sustainable, and economical production of food. Founded in 1908, PSA has a global membership of about 3,500. For more information, go to http://www.poultryscience.org.