Abstract. The present 12-month feeding study was carried out with rat groups fed a diet supplemented with meat or milk (meat/milk) derived from the progeny of clones produced by somatic cell nuclear transfer (SCNT) technology. It was conducted to obtain data concerning the chronic toxicities of these edible products during the process of development and reproduction in rats fed such products. The rats were subjected to clinical observations for general health condition and examinations such as sensory/reflex function, grip strength, motor activity, body weight, food consumption, ophthalmology and urinalysis. Moreover, sexually matured rats fed the test diets were mated and examined for items such as the reproductive performances of the dams and health of their pups. After the feeding period, factors related to rat health status, based on the findings for hematology, blood biochemistry, necropsy, organ weight and histology, were examined. There were no biologically significant differences in these factors between the rat groups fed meat/milk powder supplemented diets derived from the progeny and those fed meat/milk powder supplemented diets derived from conventionally bred cattle. Therefore, the present chronic toxicity study suggests that meat and milk derived from the progeny of SCNT cattle might be equivalent to those derived from conventionally bred cattle in use as dietary supplements for rats.

An investigation was performed on a method for detecting abnormalities in central nervous system, viscera and skeletons in chicken embryos. The examination of the nervous system and viscera was performed on embryos that had been fixed with BOUIN's solution for more than a week, basically accoding to the methods of WILSON (1965) or BARROW & TAYLOR (1969) designed for mammalian fetuses, but with occasional modifications when required. As a result, the present procedure proved to be an excellent method. When 6-aminonicotinamide was injected into yolk sac, hypoplasia of the heart in one case, hypoplasia of the left hepatic lobe in another case were found, indicating the effectiveness of this method as a teratological test. To examine the skeleton, embryos fixed with ethanol were skinned, defatted in acetone, cleared with 1% aqueous KOH containing 0.1% H2O2, and stained with alizarin red S. As a result, good stained specimens were obtained. Skeletal specimens were also prepared from 6-aminonicotinamide-treated embryos. These specimens revealed fused cervical vertebrae, fused lumbosacral vertebrae, delayed ossification of the caudal vertebrae, uncinate process, sternebrae, and digitus manus bones. These findings indicate that this method can serve as a useful teratological test.

The purpose of this study was to examine the effects of solvents, injection sites and embryo age when using chicken embryos for teratological testing. The results obtained were as follows : 1) Solvents : distilled water, physiological saline, sesame oil, 25% ethanol, 0.5% carboxymethylcellulose and 0.1% methylcellulose solution were not toxic in Day-4 embryos (eggs incubated for 4 days). 2) With 6-aminonicotinamide, air space injection more effectively induced malformations in chicken embryos. With boric acid, however, yolk sac injection was better. It was shown therefore that the appropriate injection site varied according to the test drug. 3) 6-aminonicotinamide induced characteristic malformations when injected into embryos of various ages ranging from4to 13 days of incubation. On the other hand, boric acid was teratogenetic only when injected into Day-3 or Day-4 embryos. It seems, therefore, that the age of the embryo at the time of administration is of critical importance and that the optimum time of administration varies according to the test drug.