Potential goitrogenic and toxic effects of an indole glucosinolate extract injected into the developing chick embryo

Goitrogenic and toxic effects of an indole glucosinolate extract were assessed using a chick-embryo biassay. An indole extract from brussels sprouts was dissolved in saline at 20 and 40 mg mL −1 and 0.1 mL aliquots were then injected into the egg yolk and blood of developing embryos (15 eggs/treatment) on day 10 of incubation. Aliquots (0.1 mL) of thiourea (10 mg mL −1 saline) were also injected into the yolk and blood (15 eggs/treatment) as positive controls. Thiourea injections increased thyroid weights (P < 0.001), decreased serum thyroxine (P < 0.001) and reduced the length of the duodenum (P < 0.01). Indole glucosinolates did not affect thyroid function but increased chick mortality (P < 0.005). More embryos died from intravenous (IV) injections than from injections into the yolk (P < 0.005). Deaths from IV injections occurred mainly on day 10 of incubation while deaths attributed to yolk injections occurred on days 16 – 21 (P < 0.025). Indole glucosinolates in this experiment were not goitrogenic but did increase the incidence of chick embryo mortality.