Haematological Reference Values for the African Giant Rat (Cricetomys gambianus) Maintained in Captivity in Ibadan, South West Nigeria

The African Giant Rat is a commonly consumed bushmeat species and an emerging laboratory animal model in West Africa, yet species-specific haematological reference ranges under Nigerian captive conditions remain poorly documented. This study established haematological reference values for captive Cricetomys gambianus in Ibadan, Oyo State, South West Nigeria. Sixty adult animals comprising thirty males and thirty females were bred and maintained at the Animal House of the University of Ibadan under standardised conditions. Peripheral blood collected from the retro-orbital plexus was analysed for packed cell volume, haemoglobin, red blood cell count, mean corpuscular volume, mean corpuscular haemoglobin concentration, white blood cell count, and differential leucocyte counts using standard clinical haematology methods. Mean packed cell volume and haemoglobin values were 43.5% and 14.2 g/dL respectively, with males recording marginally higher erythrocytic values than females. Neutrophil-lymphocyte ratios suggested a lymphocyte-predominant leucocyte profile consistent with small prey rodents. Sex-based differences were statistically significant for several parameters, underscoring the importance of sex stratification in reference interval establishment. The reference values generated in this study provide a validated baseline for clinical, nutritional, and pharmacological research involving this species in Nigerian academic and research institutions. Keywords: Cricetomys gambianus, haematology, reference values, captivity, South West Nigeria.