Intoxication Potential of Sublethal Doses of Bromadiolone in House Rat (Rattus rattus)

Broamadiolone is an anticoagulant, recommended as 0.005% bait for controlling rodent pests. Present study was conducted to investigate the toxicity potential of sublethal doses of bromadiolone (0.001% bait) along with blood clotting response in house rat, Rattus rattus. Mature and healthy rats of both sexes were divided into three groups. Rats of group I were fed on bait containing 0.001% bromadiolone for 24 hours. In group II, male rats were fed on 0.001% bromadiolone bait @ 2.1g/100g b.wt and female rats @ 3.7 g/100g b.wt. (equivalent to LD₅₀ of recommended bait of bromadiolone (0.005%) for male and female rats). In group III, male rats were fed on 0.001% bromadiolone bait @ 4.2g/100g b. wt. and female rats @ 7.4 g/100g b.wt. (equivalent to double the LD₅₀ of 0.005% bromadiolone bait for male and female rats). Data was analysed using Student's t-test. Complete mortality was observed in rats of group I and group III within 2–8 days and 4–14 days, respectively. Rats of group I had ingested 13.5–14.3 g/100g b.wt. of bait in 24 hours. However, only 20–30% mortality was observed in rats of group II within 7–12 days. A significant (P < 0.05) increase in blood clotting response parameters i.e. PT (Prothrombin Time), R (Prothrombin Ratio) and INR (International Normalized Ratio) was recorded in both male and female rats after 48 hours of treatment. The study suggests the use of 0.001% bromadiolone bait for control of R. rattus.