HEMATOLOGICAL INDICES ON HEAT ADAPTED RATS

ABSTRACT

Frequent exposure to hot environmental conditions is known to elicit responses that attenuates the negative effects of heat stress. The aim of this study is to investigate the hematological parameters of heat adapted Wister rats. To this effect, thirty Wister rats were obtained for this study and divided into four groups; two control groups (A and C) and two test groups (B and D). The test groups were exposed to an environmental temperature of 42±1oC. Group B was exposed to heat for 5 hours daily through a period of 14 days and sacrificed along with control group ‘A’. Similarly, group D was exposed to heat for 28 days and sacrificed along with control group ‘C’. This desired temperature was simulated using electric bulbs fixed into their cages. At the end of the study, their blood samples were collected and tested for hematological parameters. The study showed relatively stable Red cell indices except for MCHC at the 14th day and HCT on day 28 when compared with control (p<0.05). Also, WBC total count was not significantly different from that of control, however there was a significant increase in lymphocyte percentage count at the 14th day (p<0.05) while granulocytes were significantly increased on the 28th day when compared with control (p<0.05, respectively). Platelets however remained relatively unchanged throughout the study. In conclusion, a relative decrease in MCHC on the 14th day coupled with a general increase in WBC especially after the 28th day of continuous exposure to heat could be the physiological adaptation phenomena associated with heat stress. In addition, heat stress may be a risk factor for abnormal WBC and HCT levels.