He said it has been fuelled by activist groups opposed to conventional animal agriculture that use this issue, as well as those of food safety, animal welfare and environmental pollution to further their cause, scare the public and ultimately impose their views on society,

The goal of some of the most extreme activist groups is to convert the entire society to vegetarianism, Dr Cervantes said.

In a report presented at the 2007 U.S. Poultry and Egg Association Poultry Production and Health Seminar in Memphis, Tennessee, USA he said that the media in general and some politicians have seized the opportunity to gain higher ratings and more votes by sensationalised reporting and legislative proposals to restrict their use in the USA.

However, he adds that in spite of more than 50 years of use and an endless search for a "smoking gun", to this date, not a single human fatality has been linked directly and unequivocally to the use of antibiotic feed additives in food animal production.

"Contrary to public perception, the continued use of antibiotic feed additives is beneficial for both, animal and human health," said Dr Cervantes.

He said that there are numerous scientifically documented benefits derived directly from their use, such as the prevention and control of enteric diseases, enhanced food safety, improved animal welfare, preservation and less contamination of the environment, improved efficiency of production and lower cost of production resulting in lower prices for the consumers who can continue to enjoy an abundant supply of safe and nutritious food products of animal origin at an affordable price.

In his presentation to the US Poultry and Egg Association, Dr Cervantes said that the debate about whether antibiotics should be added to animal feeds at low or subtherapeutic levels dates back to the beginning of their use as feed additives in food-producing animals.

Swann Report

He said that since the Swann report was made public in 1969, the common practice of adding antibiotics at low levels to the feed of animals destined for human consumption has been further scrutinized for its potential to create antibiotic resistance.

"The Swann report suggested that antibiotic feed additives from the same classes used in human medicine not be used in food-producing animals," he said.

"More recently, the World Health Organization has also made similar suggestions but has been willing to allow continued usage when proper scientific risk assessments have been conducted (WHO, 2000).

"Numerous scientific reviews have been conducted to determine if this practice poses a significant risk to human health. Most scientific reviews (NRC, 1998; Bezoen, et. al., 1999; USGAO, 1999; I. Phillips, et. al, 2004; IFT Expert Report, 2006) acknowledge the fact that feeding low levels of antibiotics to food-producing animals can result in the development of antibiotic resistant bacteria and, therefore, a theoretical risk to humans that come in contact with the animals or consume their products, as they have acknowledged the theoretical risk to humans posed by house pets that have been treated with antibiotics.

Antibiotic Resistance

Likewise, the scientific reviews have concluded that antibiotic use in humans is the driving force behind the antibiotic resistance problems encountered in human medicine and that the practice of feeding low levels of antibiotics to food-producing animals poses no immediate or imminent threat to human health, as this practice has been in existence for over 50 years and to this date there has not been a single documented human fatality unequivocally linked to their use in food-producing animals."

However in his presentation, Dr Cervantes concludes that there are numerous scientifically documented benefits such as the prevention of subclinical diseases, reduction of human pathogens, improved animal welfare, enhanced production efficiency, preservation and less contamination of the environment, lower costs of production and lower meat prices for the consumer that are directly derived from the inclusion of antibiotic feed additives at low levels in animal feeds (E. Roura, et. al., 1992; I. Phillips, et. al., 2004; IFT Expert Report, 2006).

He said there is little to no evidence to support the claim that the use of antibiotic feed additives in animals feeds has contributed to the problem of antibiotic resistance in human medicine, since their use has been in existence for many years without any measurable adverse effects on human health (I. Phillips, 1999; I. Phillips, et. al., 2004; IFT Expert Report, 2006).

He adds that the scientific reviews also acknowledge the fact that antibiotic use by humans is the driving force behind the antibiotic resistance problems encountered in human medicine, as they have also acknowledged the fact that house pets treated with antibiotics may pose an even greater risk of transfer of antibiotic-resistant bacteria to people due to the intimate association between people and their pets.

EU Commission Ban

The EU Commission banned the use of all antibiotic feed additives classed as growth promoters in the EU against the advice of its own Scientific Committee on Animal Nutrition (SCAN, 1996; SCAN, 1998). Certain Scandinavian countries that had already unilaterally banned the use of some or all antibiotics at low levels in animal feeds put political pressure on the EU Commission to impose their policy across all EU member countries (P.E.V. Williams, 2001).

Dr Cervantes said: "The Commission succumbed to the political pressures from the Scandinavian countries and banned the use of all antibiotic feed additives classed as growth promoters starting with avoparcin in 1997 and ending with the remaining antibiotic feed additives on January 1, 2006.

"Since all the antibiotic feed additives had passed stringent regulatory reviews for efficacy and safety for animals, humans and the environment, the EU Commission had to resort to the precautionary principle to implement the ban.

"Almost immediately after the ban a surge of enteric disease problems in food-producing animals arouse. The surge in enteric diseases of food-producing animals was followed by a surge in antibiotic use in food-producing animals for therapeutic purposes.

"The antibiotics used to treat food-producing animals belong to the same classes of antibiotics most frequently used in human medicine, this might have actually had a more adverse effect on the creation of antibiotic resistance in people than the use of the antibiotic feed additives.

"The surge in use of antibiotics for therapeutic purposes in food-producing animals has clearly proven that the prior use of antibiotic feed additives had a health promotional and disease prevention effect in food-producing animals even when used at concentrations labelled for 'growth promotion'.

"Although the antibiotic feed additive bans implemented by the EU achieved the objective of reducing the prevalence of resistance in indicator bacteria in raw food products of animal origin, this has not resulted in any measurable improvement on the problem related to antibiotic resistance in human patients or human hospitals."

Dr Cervantes said that antibiotic-resistance is an extremely complex problem that is not fully understood and does not lend itself to simplistic solutions like the banning of the antibiotic feed additives.

"Research continues to produce surprising findings, for example, University of Georgia researchers recently reported that chicks raised under pristine laboratory conditions and never exposed to antibiotics had a significant prevalence of antibiotic-resistant bacteria (J.L. Smith, et. al., 2007)," he said.

"As it has been learned from the EU experience, it is not only important to assess the risk of continuing a practice (like the feeding of subtherapeutic levels of antibiotics to food-producing animals) but it is equally or even more important to assess the risk of discontinuing that same practice. As it has been learned from the EU experience, discontinuing a practice for political reasons without the proper risk analysis may have results opposite to its intended ones."

Further Reading

- You can view Dr Cervantes' full presentation to the 2007 U.S. Poultry and Egg Association Poultry Production and Health Seminar by clicking here.

December 2007