Effect of cinnamic aldehyde as repellent on behaviour and gastrointestinal tract of house rat, <em>Rattus rattus</em>

Abstract

Cinnamic aldehyde (CA) is a major constituent of cinnamomum bark oil. Though there are reports on the antifeedant effect of CA in house rat, understanding its effect on behaviour and gastrointestinal tract of house rat is necessary to develop an effective formulation for its field application against commensal rodents. In the present investigation, rats were fed on plain bait and 5% CA treated bait both under no-choice and bi-choice conditions for 30 days. Results revealed its potential as an antifeedant against <em>R. rattus </em>under both no-choice and bi-choice conditions. However, antifeedant/secondary repellent effect of 5% CA was more under bi-choice conditions. Studies on feeding and tactile behaviour of rats in response to 5% CA also revealed its irritant effect. Histomorphological studies on stomach and intestine of 5% CA treated rats revealed that in no-choice group of rats, 5% CA caused hyperplasia of non-glandular stomach and also caused reduction in number of cells of both intestinal and gastric glands which might have caused reduction in secretion of digestive juices and hormones resulting in reduction in consumption of treated bait. But in bi-choice group, GI tract was not affected. Reduction in consumption of treated bait in bi-choice group of rats might have occurred due to its irritant effect on skin and eyes of rats causing rats to prefer alternate plain bait under bi-choice conditions.