COS 70-2 - Fertility control of rodent pest population: Castor bean (Ricinus communis L.) powder as a potential candidate plant material in wild african giant rats ( Cricetomys gambianus W.)

Abstract: Managing rodent pest species using synthetic rodenticides to achieve lethality has been considered an unsustainable management strategy because of their attendant shortcomings such as bait shyness, secondary poisoning, effects on non target species in the ecosystem etc. An alternative ecofriendly option needs to be developed and one of such is the use of plant materials with the potential of reducing the reproduction of rodent pest species.

The present study evaluates the potential of Castor seed (Ricinus communis) powder-formulated feed in the fertility control of wildly caught female African giant rats (Cricetomys gambianus) (a notable rodent pest). Four different concentrations of experimental feeds were formulated by mixing Castor seed powder with Commercial rat feed in the ratio 1:12, 1:6, 1:1 while only Commercial rat feed served as control. Twenty (20) wildly caught female African giant rats were randomly allocated into four groups (with 5 animals/group), acclimatized for 4 weeks and fed with appropriate experimental feed for 60 days with water provided ad libitum. Blood samples were collected at 20 days intervals for serum biochemistry analysis - reproductive hormone which include Follicle Stimulating Hormone (FSH), Luteinising Hormone (LH), Prolactin (PRL), Progesterone (PROG), and Estrogen (ESTR); and cellular enzymes which include Aspartate Aminotransferase (AST), Alanine Aminotransferase (ALT), and Alkaline Phosphatase (ALP).

The results showed progressive decrease in the hormone level with time in all the experimental groups. There was significant reduction in the reproductive hormones in all the experimental groups compared with the control (p ˂ 0.05). No significant difference was recorded in the mean feed intake (%) among the groups (p ˃ 0.05). The mean body weight among the groups showed no significant difference (p ˃ 0.05).

Conclusively, the Castor seed powder has the potential of reducing the reproductive ability of the female African giant rats and this is considered a more environment-friendly rodent population management option compared to the conventional method of rodent control using synthetic rodenticides. It could therefore be recommended to the farmers for use.