Effect Of Age On Immune Response Of Trypanosome-Infected Rats (Rattus rattus) Fed Dietary Vitamin E And Selenium

Abstract

This study was done to determine the combined effects of dietary supplementation of vitamin E and selenium on age-dependent immune response of Trypanosoma congolense-infected white rats (Rattus rattus, whiskers breed). Sixty rats were used in the study, 30 20-day old (newly weaned) rats and 30 90-day old (adult) rats. Four groups of rats with five rats of identical age per group were kept in wre-rat-cages. The cages were labeled G to J. Cage G contained adult rats (Control 1), while cage H contained newly weanedrats (Control 2). Cage I contained adult rats fed diet containing selenium and vitamin E (nutrient), while cage J contained newy weaned rats also fed diets containing selenium and vitamin E. Each treatment was replicated three times. Longevity (days of survival) and differential leucocyte counts which are functions of immune response of the rats upon infection with T. congolense were determined. At the end of the study, the longevity and differential leucocyte counts were analysed for significant differences using analysis of variance (ANOVA) and any differences were partitioned with the least significant difference (LSD) and the Duncan's Multiple Range Test (DMRT). The resultsrevealed that there was no significant difference in longevity (P > 0.05) between the two control groups (newly weaned and adult rats) but there were significant differences between the longevity of each control group and the longevities of the rats given combned dietary supplementation of the nutrients. Longevity of newy weaned and adult rats given dietary supplementation of selenium andvitamin E were not different (P< 0.05). These results implied that age of the rats was not a contributory factor in improved immune response of the trypanosome-infected rats fed the combined dietary supplementation of selenium and vitamin E.

Keywords: Immune response, Newly weaned rats, Longevity, Trypanosoma congolense, Rattus rattus

Animal Research International Vol. 1 (2) 2004 pp. 70-76