Beyond Sub-therapeutic Antibiotics: A Paradigm Shift for a Traditional Industry

Peter Karnezos Ph.D

Alltech Inc., Nicholasville, KY

Since the mid 1940’s the use of sub-therapeutic antibiotics as growth promotants in swine and poultry diets has been a standard animal husbandry practice. Until recently little attention was given to the potential threat to society that the continuous use of sub-therapeutic antibiotics in animal feeds posed to the human population. The up-serge in diseases that had virtually disappeared over the past 50 years like tuberculosis, meningitis, diphtheria and salmonellosis ignited concerns about antibiotic resistance caused by sub-therapeutic antibiotic use in the animal feed industry.

In 1999 the Agricultural Commissioner for the European Union responding to pressure from non-government organizations and consumer groups over their concerns about antibiotic use in the animal feed industry and possible links to antibiotic resistance, banned the use of a number of antibiotics such as, virginiamycin, spiramycin, zinc bacitracin and tylosin. In 2002 the EU declared that by the end of 2004 all sub-therapeutic antibiotics will be banned.

In the USA the Center for Veterinary Medicine has established the National Antimicrobial Resistance Monitoring System to evaluate the associated risks of antimicrobial use in animal feeds. The supermarkets, fast-food chains and marketing teams responding to consumer concerns have left the scientific debate and are actively demanding and promoting products free of antimicrobial growth promotants. As a result, the animal feed industry has to respond with alternative management and feeding strategies to ensure the economic, safe and environmentally friendly production of meat, milk and eggs.

A number of strategies are emerging for increasing animal performance in the absence of specific antibiotic growth promotants. These include the use of direct-fed microbial supplements, non-digestible carbohydrates, acidifying agents, herbs and spices and exogenous enzymes. Data indicates that animal well-being and performance criteria can be met using the appropriate management and alternative supplementation strategies despite the removal of traditional antimicrobial growth promoters. The consequence of these alternative strategies, significantly reduces the contribution of sub-therapeutic antibiotics on antibiotic resistant pathogens affecting both animal and human health.