ISSN 2320-5407 International Journal of Advanced Research (2014), Volume 2, Issue 12, 939-945 939 Journal homepage: http://www.journalijar.com INTERNATIONAL JOURNAL OF ADVANCED RESEARCH RESEARCH ARTICLE Determination of lethal feeding period of bromadiolone anticoagulant for screening individual rats (Rattus rattus) for development of resistance Nancy Garg* and Neena Singla Department of Zoology, Punjab Agricultural University, Ludhiana-141004, India. Manuscript Info Abstract Manuscript History: Received: 22 October 2014 Final Accepted: 23 November 2014 Published Online: December 2014 Key words: Anticoagulant, bromadiolone, lethal feeding period, mortality, Rattus rattus *Corresponding Author Nancy Garg garg.naina1@gmail.com; neenasingla1@gmail.com The second generation anticoagulant, bromadiolone, is presently being used worldwide for control of rodent pests, however, its intensive use has led to the development of resistant rat populations in many parts of the world. In India, there is no report on the development of resistance against bromadiolone. Present study was conducted to determine lethal feeding period of bromadiolone against house rat, Rattus rattus, one of the most common commensal rodent pest worldwide in order to further use it for screening of rats for development of resistance. A total of eight groups of both the sexes (n=5 per group) were fed on cereal based 0.005% bromadiolone bait for variable periods i.e. 0, 2, 4, 8, 16, 24, 48 and 72 hrs in no-choice feeding tests. Lethal feeding period (LFP 50 ) was found to be 4.69 and 5.63 hrs for male and female rats, respectively. Different LFP 50 values for two sexes indicate sex specific variations. None of the rat of either sex survived after 16, 24, 48 and 72 hrs of feeding test while 60% mortality was achieved in both the sexes after 8 hrs of feeding test. Feeding durations equivalent to LFP 50 and double the LFP 50 can be used for screening populations of R. rattus for bromadiolone resistance. Copy Right, IJAR, 2014,. All rights reserved Introduction The house rat, Rattus rattus Linnaeus, 1758 (Rodentia: Muridae), is one of the most commonly encountered and economically important commensal rodent pest (Parshad, 1999). It not only inflicts heavy damage to stored food but also has nuisance value being a disease carrier or vector (Singla et al., 2008). It is purely an indoor pest (Roberts, 1977; Brooks et al., 1987). Among all the available methods, chemical control by rodenticides is the most widely used and efficient method for the control of rodent pests both under agricultural and commensal situations (Prakash and Mathur, 1987; Chopra et al., 1996). Zinc phosphide, an acute rodenticide has been used predominantly over several years. However, its repeated use leads to rapidly recovering and bait shy rodent populations (Parshad, 1989; El-Deeb et al., 2011). With the development of first generation chronic anticoagulant rodenticides, it was possible to control bait shy rodent populations. However, within a few years of their continuous use, resistance to almost all of the anticoagulants was detected in most of the countries including India (Boyle, 1960; Deoras, 1966; Jackson and Kaukeinen, 1972; Mukthabai et al., 1981). The second generation anticoagulants such as bromadiolone, were developed to combat resistance to first generation anticoagulants. But after a very short time, the initial success of these compounds was shaken by the reports indicating rodent populations showing cross resistance to them (Redfern and Gill, 1980; Rowe et al., 1981; Lund, 1984). The resistance to second generation anticoagulants has not become as wide spread as to the first generation anticoagulants (Buckle, 1994). Today, resistance to both first and second generation anticoagulants has been reported in the United Kingdom, Germany, Denmark, Belgium and the Netherlands (Pelz, 2001; Lodal, 2001; Pelz and Klemann, 2004; Pelz et al., 2005; Diaz et al., 2010; Baert et al., 2012). No case of resistance to bromadiolone has yet been reported from India.