Synergistic effect of bromadiolone and cholecalciferol (vitamin D3) against house rat, Rattus rattus

Abstract

Commensal rodents, especially house rat (Rattus rattus) causes extensive losses by feeding and contaminating the food products and also plays a role in spreading several diseases of health importance. House rats trapped from various commensal situations of Ludhiana city were fed for 5 days in no-choice on self made formulations of bromadiolone (Br) and cholecalciferol (Cc)/vitamin D3 baits having different concentrations (less than their standard concentrations i.e <0.005% Br and <0.075% Cc) mixed in plain WSO- mix bait. Both male and female house rats were fed on four formulated baits viz. combination-I (0.0025% Br + 0.05% Cc), combination-II (0.001% Br + 0.05% Cc), combination-III (0.0025% Br + 0.01% Cc) and combination-IV (0.001% Br + 0.01% Cc). Out of these four tested formulated baits, combination-IV, having the lowest concentration of Br and Cc showed significantly higher rodenticidal potential in terms of 100% killing of rats within average time of 3.33±0.23 days in males and 4.00±0.40 days in female rats. Feeding of combination-IV resulted in delaying the blood clotting time by 55.00±1.90 sec. in males and 65.00±0.87 sec. in females as compared to the untreated rats due to the action of bromadiolone present in the formulated bait even at its concentration @ 0.001%. In this lowest tested formulation, the feeding of cholecalciferol @ 0.01% was able to increase the serum calcium level (mg/dL) significantly up to 3.66±0.93 inmales and 2.94±0.92 in females in comparison to untreated rats. The study revealed that the combination-IV i.e formulation with least tested concentration of Br and Cc was found to have potent rodenticidal efficiency as well as cost effective bait for the control of house rats under