Daily changes in body temperature as well as physical activeness from mating to pregnancy were illustrated in MF1 mice. Body temperature and physical activity gradually declined as pregnancy advanced while energy intake and body mass increased in late pregnancy. Diurnal and nocturnal locomotor activity and body temperature were significantly lower in late pregnancy than in non-reproductive and mating phases. Despite low physical activity, inactive body temperature was relatively high through late pregnancy. This suggests that pregnant mice tend to increase thermogenesis against a drop of body temperature. Energy intake increased remarkably after parturition and reached a plateau in late lactation suggesting a limit of energy intake. Litter size and litter mass significantly influenced maternal energy intake and body mass (<i>P</i><0.05). However, daily pup mass gain declined at the peak lactation when maternal energy intake was limited. Body temperature rose sharply after parturition. Body temperature during the day considerably increased. Consequently, lactating mice faced a constantly high body temperature through the day despite lower activity levels. There were no trends that litter size and litter mass stimulated maternal body temperature and physical activity on average through lactation. Body temperature during suckling inside the nest increased towards the end of suckling. However, no significant increase in body temperature was found between 20 and 1 minutes before terminating suckling bouts. Dams that raised larger litters encountered higher body temperature while suckling inside the nest, suggesting that suckling offspring considerably contributed to heat retention in mothers. Suckling offspring appeared to prevent mothers from releasing cumulative heat, although the significance of suckling behaviour on overheating was smaller than that of metabolic heat generation.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:521186 |
| Date | January 2009 |
| Creators | Gamo, Yuko |
| Publisher | University of Aberdeen |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=130928 |
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