[Results of 8 years' research on the toxicologic evaluation of animal food additives by the so-called relay toxicity method].

The authors report the underlying principles of the new methodological approach called "relay toxicity" which they proposed eight years ago for the toxicological evaluation of animal feed additives. They stress its value either as a possible criterion of rejection or as a criterion of acceptability. In the latter case, the limiting factor is the difficulty of applying an adequate safety factor when food products destined for human consumption and obtained from animals receiving the additives to be evaluated are administered to laboratory animals. Amongst the examples of the additives which have been subjected to toxicological evaluation using the authors' new method, the following are examined: as growth factor, carbadox, anabolising agents and, in particular, diethylstilboestrol, and steroids used as egglaying potentializers. The results obtained are discussed.