THE EFFECT OF PSEUDORABIES VIRUS GROWTH-FACTOR (PRGF) ON EMBRYONIC AND LARVAL DEVELOPMENT OF ZEBRAFISH (DANIO-RERIO) AND JUVENILES OF GUPPY(POECILIA-RETICULATA)

The effect of pseudorabies virus growth factor (PRGF) on two fish spec ies in two different developmental stages was investigated, namely, on undifferentiated cells represented by fertilised zebrafish eggs, and on already formed organisms represented by newly hatched guppy. PRGF d issolved in water at concentrations 1x10(3) to 1x10(13) units/ml was t eratogenic and at concentrations 1x10(7) to 1x10(13) units/ml was toxi c. The importance and the extent of the effect was dependent on the ty pe of affected cells, the concentration of PRGF and the stage when a c ell was affected in the developing fish embryo. The exposure of Danio rerio eggs to PRGF at high concentrations (1x10(7) to 1x10(13)) slowed down significantly the development of juveniles and retarded the grow th of their weight and length. On the other hand, PRGF at low concentr ations (1x10(5) to 1x10(3)) significantly stimulated the growth of the ir weight and length.