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U.S. Department of Health and Human Services

Animal & Veterinary

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FDA Veterinarian Newsletter September/October 2000 Volume XV, No. V

CVM cosponsored a symposium on the use of herbs and botanicals in livestock diets. The symposium was held July 25, 2000, in conjunction with the ADSA-ASAS Joint Annual Meeting, Baltimore, Maryland. The meeting was intended to raise awareness on this important issue, since, in the past few years, the explosion in sales of botanicals and herbs, has brought many products to the marketplace that do not conform to the standards of safety and efficacy expected. Approximately 200 people attended the meeting.

Introductory comments were provided by Drs. G. L. Cromwell, Chair of FASS Committee on Food Safety, Animal Drugs, and Animal Health and C.B. Ammerman, University of Florida. Also, as part of the opening session, Dr. Sharon Benz (Division of Animal Feeds) spoke on the regulation of botanical and herbal substances in animal feeds. Dr. Benz provided an overview of the FDA’s regulation of animal feed products and highlighted the differences of the animal feed and feed supplement regulations compared to the regulations for dietary supplements intended for humans. Specifically, she addressed why Congress did not intend DSHEA (Dietary Supplement Health & Education Act) to apply to products for use in animals. Before finishing, she expressed the safety concerns FDA has regarding the use of botanical and herbal ingredients that are not recognized for use in animal diets.

Dr. Caspar Wenk, a distinguished speaker of the Institute of Animal Sciences, ETH Zurich, Switzerland, spoke on the use of herbs and botanicals in European livestock nutrition. Depending on the intended use, herbs are regulated in Europe as feedstuffs, feed additives or medical drugs. Typical uses discussed were as flavoring agents, antioxidants, endocrine stimulants, antimicrobial agents, or anthelmintic agents. Herbs that have shown antimicrobial activities in livestock and poultry include oregano, laurel, rosemary, coriander, and sage. Herbal feed antioxidants include rosemary, sage, thyme, and oregano. Rosemary is the most used herbal antioxidant in Europe. Dr. Wenk emphasized that, with the ban of antibiotics in Europe, the use of herbs has become an important alternative.

Professor Peter Cheeke, Oregon State University, Corvallis, Oregon, provided the results of recent research on the use of herbs in livestock nutrition. Prof. Cheeke discussed the results of poultry and swine studies which tested yucca as an odor and ammonia control agent. In addition, due to their possible role in lowering blood cholesterol, yucca saponins are also being tested for this and other therapeutic uses.

Dr. Kyle E. Newman, Venture Laboratories, Lexington, Kentucky, addressed the chemistry of herbs and botanicals with regard to the safety for animals. For instance, chaparral contains the antibiotic nordihydroguaiaretic acid (NDGA) which has shown to be effective against skin infections; however, this compound causes allergic contact dermatitis. In addition, although a potent antioxidant, the hepatotoxic effects of chaparral have been demonstrated in animal studies. During his closing remarks, Dr. Newman pointed out the importance of standardization (proper processing) of the "active" ingredients to prevent contamination (heavy metals, pesticides).