Energy balance of pregnant rats in a cold environment

Abstract

1. 1.|The present investigation was performed to verify how energy balance of pregnant rats could be affected by cold exposure during pregnancy and by cold acclimation before being pregnant. 2. 2.|Depending on the environmental treatment applied to the animals, gestation increased body weight gain between 500 and 1000%, metabolizable energy intake between 12 and 25%, body energy gain between 19 and 1000%, energy expenditure between 7 and 13%, and gross food efficiency between 38 and 1000%. 3. 3.|The cold environment decreased body weight and energy gains and gross food efficiency in different amounts depending on whether the animals were pregnant and whether they were cold acclimated. The decreases ranged between 20 and 100%. Energy intake and expenditure increased by between 48 and 85%. 4. 4.|Cold acclimation improved body energy gain by 900% and gross food efficiency by 500% in non-pregnant rats compared with cold exposed animals, so that in the cold acclimated group no differences in those parameters were detected between pregnant and non-pregnant rats. 5. 5.|The number and energy content of the offspring were affected neither by cold exposure nor cold acclimation. 6. 6.|These results suggest that a cold environment impairs the energy balance of pregnant rats without affecting the number, weight, and energy of the offspring. The energy balance of non-pregnant animals is affected differently by a cold environment, depending on the rats being or not acclimated.