Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
ANTIBACTERIAL FEED ADDITIVES Antibiotics and other compounds with antimicrobial ac- tion, while nonnutrients, are extensively used as feed additives for swine. Such widely accepted use of these compounds relates to an improvement in growth rate and feed conversion and to reduced mortality and morbidity, particularly in young swine. Approved antibacterial agents commonly added to swine feeds in the United States and Canada include bacitracin, bambermycins, carbadox, chlortetracycline, lincomycin, oleandomycin, oxytetracycline, penicillin, streptomycin, tylosin, virgin- iamycin, arsenicals, nitrofurans, and sulfa drugs.While not approved for use in the United States or Canada, the ad- dition of 125 to 250 ppm of copper as a growth promoter in growing and finishing feeds is common in Great Britain and a number of other countries. How the low-level consumption of these compounds, which differ widely in chemical composition and bacte- rial spectrum, influences performance is not well under- stood. Since they suppress or inhibit the growth of certain microorganisms, it is assumed that such action relates directly or indirectly to this property. The consumption of these compounds is capable of promoting the development of bacterial resistance in the animals' microbial population. Furthermore, it is known that such resistance can be transferred between bacteria. The significance of this phenomenon, as it may relate to the health of animals and man, has not been determined. In view of the potential threat from a buildup of multiple bacterial resistance, the Food and Drug Administration has proposed that the subtherapeutic use of certain an- tibacterial compounds in feed be restricted. Thus, it is important to recognize that approved usage of any feed additive is subject to change and that constraints on their use will vary among countries. Detailed information on specific antimicrobial agents, levels of usage, and legal requirements for use may be found in the Feed Additive Compendium, published each year by the Miller Publishing Company, 2501 Wayzata Boulevard, Minneapolis, Minnesota 55440, and in the compendium of Medicating Ingredient Brochures, Plant Products Division, Canada Department of Agricul- ture, Ottawa, Canada. For official information concerning Food and Drug Administration approval of antibiotics and other animal drugs, the Code of Federal Regulations (CFR), Title 21, should be consulted. Title 21 is revised at least once each year as of April 1. The CFR is kept up to date by the individual issues of the Federal Register. These two pub- lications must be used together to determine the latest version of any given rule. Title 21 is published in six parts: Part 500-599 covers animal drugs, feeds, and re- lated products and is for sale by the Superintendent of Documents, U.S. Government Printing Office, Washing- ton, D.C. 20402 ($5.00). The Federal Register is available from the Superintendent of Documents ($50.00/year) and includes monthly issues of the List of CFR Sections Affected and The Federal Register Index. 13