Subchronic dietary toxicity of strychnine: bobwhite quail are less sensitive than mallard ducks

Separate, 28-day, subchronic studies of strychnine dietary toxicity were conducted using northern bobwhite quail (Colinus virginianus) and mallard ducks (Anas platyrhynchos). Five groups (five males five females/group) of 29-week-old quail were fed Purina(R) Game Bird Breeder Layena(R) diets containing mean (+/-SD) 484.2 (+/-17.0), 972. 6 (+/-54.0), 1,870.8 (+/-176.1), 3,516.7 (+/-68.0), and 6,083.3 (+/-269.6) microgram/g strychnine; whereas five groups of 27-week-old mallards (five males five females/group) were fed similar diets containing mean (+/-SD) 18.8 (+/-1.3), 91.1 (+/-27.3), 235.0 (+/-33. 8), 484.2 (+/-17.0), and 972.6 (+/-54.0) microgram/g strychnine. Separate "vehicle control" (0.0 microgram/g strychnine) groups (five males, five females/group) were included in each study. Strychnine toxicity was much less pronounced in quail; no observed effect concentrations (NOECs) were 972.6 (+/-54.0) and 91.1 (+/-27.3) microgram/g strychnine for quail and ducks, respectively. Several possible explanations for the species effects are offered, and some practical issues affecting the conduct of long-term, dietary toxicity studies are discussed.