I. Hirono et al., REPRODUCTION OF PROGRESSIVE RETINAL DEGENERATION (BRIGHT BLINDNESS) IN SHEEP BY ADMINISTRATION OF PTAQUILOSIDE CONTAINED IN BRACKEN, Journal of veterinary medical science, 55(6), 1993, pp. 979-983
The process of occurrence of bright blindness, progressive retinal deg
eneration (PRD), in sheep was observed using two Suffolk ram lambs fed
on a diet containing bracken powder. The first sign of the bright bli
ndness was detected 4 months after the start of experiment. Based on t
hese preliminary results, the amount of bracken powder necessary to in
duce PRD was estimated (experiment I). In the following experiment, pt
aquiloside (PT), a norsesquiterpene glucoside of the illudane type iso
lated from bracken. which is a bracken carcinogen and a causative prin
ciple of cattle bracken poisoning was administered to two Suffolk ram
lambs. It was clearly demonstrated in this experiment (experiment II)
that PT present in bracken is also a causative principle of PRD.