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

Abstract

An example of species sensitivity differences between mallard ducks and ring-necked pheasants was found for the toxin (anatoxin-a) produced by the freshwater cyanophyte Anabaena flos-aquae NRC-44-1. The oral LD 90 (dose required to kill 90% of animals) for pheasants was found to be 2.4 times the oral LD 90 for ducks. The sensitivity of a gastrocnemius muscle sciatic nerve preparation in pheasants was about three 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 intraperitoneal LD 90 which was 50 mg/kg body weight for ducks and 120 mg/kg body weight for pheasants. This is used as evidence for an example of species sensitivity variation to the toxin at its site of action and indicates one way in which animal losses due to field poisonings by these toxic blooms can differ.