Body composition in mink (Mustela vison) kits during 21-42 days postpartumusing estimates of hydrogen isotope dilution and direct carcass analysis

We compared carcass analysis and hydrogen isotope dilution methods to measu re total body water (TBW) and body composition in a small altricial carnivo re, the mink. Dilution space (D) of mink at 21-42 days of age (n = 20), was determined after subcutaneous administration of tritiated water. The same animals were then used to determine TBW and body composition by carcass ana lysis and to derive predictive empirical relationships between TBW and tota l body fat, protein and energy. A separate validation set of 27 kits was us ed to test the accuracy of predicting body composition from TBW. D overesti mated TBW by a consistent and predictable 4.1% (R-2 = 0.999, P < 0.001). Ou r estimates of fat, protein and energy content, using equations derived fro m TBW, were not significantly different than those obtained from direct car cass analysis (P > 0.980) in either the initial or validation set of mink. TBW was shown to decrease from 81 to 76% and total body protein to increase from 14 to 19% of LBM of the kits from 21 to 42 days of age. Although a ra pidly changing hydration state was apparent in neonates, we conclude that w hen this is taken into account, accurate estimates of body composition can be obtained from hydrogen isotope dilution. (C) 2000 Elsevier Science Inc. All rights reserved.