Toxicity and palatability of scilliroside to Rattus argentiventer

Y. M. Lam

Abstract

Scilliroside was evaluated against Rattus argentiventer  in the laboratory. The median lethal doses (LD₅₀) of scilliroside against R. argentiventer  was 0.64 mg/kg and the LD₉₉ was 2.21 mg/kg. Corrected mean days to death in rats succumbing to a lethal dose by gavage were 2.3 (SE 0.3) days in males and 1.8 (SE 0.2) days in females. Scilliroside at all the concentrations tested did not elicite 100% mortality in both sexes in 1-day no-choice tests as a result of poor bait consumption. The lowest lethal dose was 0.06 mg/kg and the highest dose survived was 1.21 mg/kg in males. In females, the lowest lethal dose was 0.10 mg/kg and the highest dose survived was 0.46 mg/kg. Corrected mean days to death in rats succumbing to a lethal dose in no-choice feeding tests were 2.0 (SE 0.6) days in males and 2.5 (SE 0.7) days in females. Palatability studies (4-day choice feeding tests) indicated that scilliroside at all the concentrations tested showed poor palatability against R. argentiventer, giving low mortality for both sexes as a result of poor consumption of the poison baits. Rats were able to detect scilliroside at the lowest concentration tested (0.01%), resulting in very poor bait consumption.

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