Effects of room temperature on reproduction, body and organ weights, food and water intakes, and hematology in mice.

Two consecutive generations of mice were raised at graded room temperatures ranging from 12 to 32 degrees C at intervals of 2 degrees C. The delivery rate decreased at 30 and 32 degrees C, and the litter size and weaning rate decreased above 28 degrees C. No significant difference was demonstrated within the 12-26 degrees C range for any reproduction parameters observed. The body weights of the first-generation mice born at 22 degrees C and transferred to rooms at assigned temperature did not significantly differ within the 14-28 degrees C range after 8 and 16 weeks of exposure. The second-generation mice born and reared at various temperature levels did not show significant inter-group difference in weight within the 20-26 degrees C range at any age in the growth period. No significant inter-group difference was observed within the 20-26 degrees C range in respect of food and water intakes in the second-generation mice. Hematological values and organ weights in the first and second generation mice of both sexes did not significantly differ in any parameter within the 20-26 degrees C range. The results suggest the temperature range of 20-26 degrees C to be optimal for laboratory mouse rooms.