Abstract
Thiopeptin is a new antibiotic, produced by Streptomyces tateyamensis and developed solely for animal use as a feed additive. The antibiotic content in animal tissue and feed was assayed in terms of the antimicrobial activity against Mycoplasma laidlawii A. This antibiotic was found to be relatively nontoxic in rats and mice. In chickens, this antibiotic is excreted into feces within 48 hr of administration and is not absorbed in tissue. It is well tolerated in both broilers and swine and is highly stable in animal feed. Thiopeptin-supplemented feed contributes to the improvement of weight gain, feed efficiency in chickens and swine, and the egg performance in layers. Thus, thiopeptin, when used as a feed additive, is quite suitable for supplementing animal nutrition.