Water turnover evaluated by the tritiated water method and by the nutritional method in European hedgehog (Erinaceus europaeus L.).

The total body water (TBW), the fractional water turnover rate (WTR), and the water flux rates (WFR) were studied for the first time by the tritiated-water method in 10 hedgehogs under laboratory conditions during the year. To validate this method, we compared the result to the nutritional method. The TBW varied inversely with body mass (BM) during both the active and the hibernation periods. The WTR varied from 16% to 21% during the hibernation period and after the reproduction. The higher values (from 22% to 26%) were recorded during the reproduction period and during the preparation for hibernation. The same variations in WFR were recorded during the active and hibernation period. The net gain or loss of water followed the gain and loss of BM. The tritiated water (THO) method has been validated by the fact that the same variations in WFR during each month have been measured by the THO method and the nutritional method. Moreover, the THO method can be used to estimate the changes in energy metabolism of hedgehogs in relation with the seasons.