Muscle sensitivity differences in two avian species to anatoxin-a produced by the freshwater cyanophyte Anabaena flos-aquae NRC-44-1

Abstract

An example of species sensitivity differences between mallard ducks and ring-necked pheasants was found for the toxin (anatoxin-.alpha.) produced by the freshwater cyanophyte A. flos-aquae NRC-44-1. The oral LD90 (dose required to kill 90% of animals) for pheasants was 2.4 times the oral LD90 for ducks. The sensitivity of a gastrocnemius muscle sciatic nerve preparation in pheasants was about 3 times less than that of the duck. Comparison of muscle sensitivity with decamethonium bromide did not show this species difference. The species difference was also observed in the i.p. LD90 which was 50 mg/kg body wt for ducks and 120 mg/kg body wt for pheasants. This is used as evidence for an example of species sensitivity variation to the toxin at its site of action and indicates 1 way in which animal losses due to field poisonings by these toxic blooms can differ.