TOXICITY STUDIES OF THE TOXINS ISOLATED FROM ANNUAL RYEGRASS (LOLIUM RIGIDUM) INFECTED BY CORYNEBACTERIUM RATHAYI

Abstract

Summary.Estimates of the LDso's of 7 glycolipid toxins (corynetoxins) isolated from toxic annual ryegrass varied in the range 01-13 mg/kg in 2-week-old rats. The delay in onset of neurological signs in rats and sheep was independent of dose rate and could be the result of inhibition of protein biosynthesis. In sheep, no influence of the route of administration on the delay in onset of neurological signs was demonstrated. The relationship between the partial structures of the two major corynetoxins and their toxicity is discussed.

Review of corynetoxins poisoning of livestock, a neurological disorder produced by a nematode‐bacterium complex

“…The thermal optimum for embryogenesis is between 18 and 20°C and the process is irreversibly inhibited at 27°C. If high temperatures supervene during egg laying and embryogenesis, egg mortality will be high, galls will contain eggs but no larvae, and there will be diminished pasture toxicity the following season 39,41–43 …”

“…The thermal optimum for embryogenesis is between 18 and 20 ° C and the process is irreversibly inhibited at 27 ° C. If high temperatures supervene during egg laying and embryogenesis, egg mortality will be high, galls will contain eggs but no larvae, and there will be diminished pasture toxicity the following season. 39,[41][42][43] The L2 that hatch commence to feed and grow into the resistant or dauer stage. The growth of these L2 during the late spring leads to dramatic changes occurring in the gall at the expense of the adult nematodes, which subsequently degenerate.…”