U.S. Department of Agriculture: Animal and Plant Health Inspection Service


Date of this Version



Published in Arch. Environ. Comm. Toxicol. 38, 530-539 (2000).


Separate subchronic reproductive toxicity studies were conducted using mallard ducks (Anas platyrhynchos) and northern bobwhite quail (Colinus virginianus). Three groups (32/group; 16 male-female pairs) of 17-week-old ducks (F0 generation) were fed Purina® Game Bird Breeder Layena® diets containing mean (±SD) 33.2 (±2.7), 68.9 (±1.8), and 140.9 (± 5.1) μg/g strychnine for 20 weeks, with some pairs in each group fed control diet during a subsequent 3-week recovery period. Three groups (32/group; 16 male-female pairs) of 19-week-old quail (F0 generation) were fed similar diets containing mean (±SD) 279.2 (±10.1), 557.4 (±43.5), and 1,113.6 (±46.6) μg/g strychnine for 22 weeks without a recovery period. Separate groups of ducks and quail (32/group; 16 male-female pairs) were also fed control dies (0.0 μg/g strychnine) in each study. There were I6 weekly collections of eggs for the mallard study (13 for the diet-exposure period and 3 for the recovery period), and 11 collections for the quail study. Eggs laid during the last 13 and 10 weeks of the diet-exposure periods for ducks (plus 3 weeks of the recovery period) and quail, respectively, were incubated. Each hatch of F1 generation ducklings and chicks was observed for 14 days. Key results were: (1) the no observed adverse effect levels (NOAELs) for F1 ducks and quail were 33.2 and 1,113.6 μg/g strychnine, Respectively – quail showed no reproductive effects at the current doses; (2) decreased egg production and hatching success occurred for mallard hens fed mean 140.9 μg/g strychnine diets; and (3) "normal-hatching" ducklings from eggs of F0 mallards fed mean 140.9 μg/g strychnine diets suffered greater mortality than ducklings from the other diet groups. Possible mechanisms of strychnine action on avian reproduction are discussed.