Effect of Forced Swimming on Body Temperatures and Eosinophil Levels in Cotton Rats (Sigmodon Hispidus)

Abstract

Cotton rats, Sigmodon hispidus, were forced to swim in water at 2 and 10° C. Body temperatures (TB) declined most rapidly during the first 6 minutes of the swim and the rate of fall was nearly halved during the remainder of the swim. the rate of decline in TB was more rapid in the 2 than in the 10° C bath, but the per cent change in TB at the end of the swimming was about the same at both bath temperatures (about 43 per cent). the mean TB of the 26 cotton rats tested was 21.4 ± 0.6° C at the end of swimming, and there was no significant difference in the total decline in TB at the two bath temperatures. the eosinophil count declined by 52.5 and 63.0 per cent in cotton rats swimming at 2 and 10° C, respectively, and there was no evident correlation between the magnitude of the eosinophil response and body weight, swimming time or percentage decrease in TB.