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Figures
- Fig. 1.
Isotopic enrichment values of the equilibration time course for (A) oxygen-18 (18O) and (B) deuterium (2H) of three green turtles (Chelonia mydas). These enrichments represent the background enrichment levels (day 0) and the enrichment levels post intra-coelomic injection and during the plateau period.
- Fig. 2.
Isotopic enrichment values for (A) oxygen-18 (18O) and (B) deuterium (2H) during the course of the doubly labeled water (DLW) validation experiment for six green turtles (Chelonia mydas). Background enrichment levels given at day 0, equilibration, fed DLW trials (days 1–6), fasting period (days 6–16), deuterium reboost (day 16), fasting DLW trials (days 16–21) and final deuterium reboost (day 21).
- Table 1.
Mass background isotope levels, injectate details, isotope dilution space, washout ratios, metabolic rate and water turnover rate for 6 green turtles used in DLW validation
Turtle L1 L2 L3 L4 R1 R4 Mean ± s.d. Sig. diff. Mass (kg) Fed 19.60 25.04 19.76 25.88 24.84 19.38 22.42±3.13 a Fasted 19.04 25.18 19.10 25.30 24.10 19.20 21.99±3.18 a Post-fast 21 days 19.48 25.06 19.44 25.50 24.38 19.46 22.22±3.04 a Post-fast 23 days 19.42 25.28 19.92 26.20 24.92 19.82 22.59±3.18 a Post-fast 25 days 19.92 25.38 20.10 26.20 25.22 19.90 22.79±3.10 a Background 2H 153.85 154.59 153.82 153.57 153.21 153.12 153.69±0.53 Background 18O 1994.64 1995.18 1994.21 1994.67 1994.82 1994.51 1994.67±0.32 Initial injectate (moles) 0.37 0.55 0.42 0.52 0.53 0.42 Injectate enrichment 2H APE 260611.09 260611.09 260611.09 260611.09 260611.09 260611.09 18O APE 695197.53 695197.53 695197.53 695197.53 695197.53 695197.53 Nd (ml) 14047.42 17593.36 14821.41 16709.71 17019.68 14014.79 15701.06±1593.03 No (ml) 13398.16 16887.24 14152.22 15862.79 16365.00 13608.91 15045.72±1508.41 Dilution ratio Nd:No 1.048 1.042 1.047 1.053 1.040 1.030 1.048±0.005 10 day fast 2H boost Injectate (moles) 0.07 0.10 0.08 0.08 0.09 0.07 0.08±0.01 15 day fast 2H boost Injectate (moles) 0.08 0.09 0.07 0.08 0.08 0.07 0.08±0.01 2H boost enrichment 2H APE 952572.52 952572.52 952572.52 952572.52 952572.52 952572.52 Fed – kd 6.399E–05 6.154E–05 8.009E–05 6.024E–05 5.836E–05 4.913E–05 6.223E–05±1.013E–05 Fed – ko 7.297E–05 6.452E–05 8.653E–05 6.704E–05 6.298E–05 5.143E–05 6.758E–05±1.166E–05 Fasted – kd 4.832E–05 3.799E–05 4.057E–05 3.925E–05 4.786E–05 4.218E–05 4.270E–05±4.406E–06 Fasted – ko 4.462E–05 3.969E–05 3.997E–05 3.616E–05 3.500E–05 4.490E–05 4.006E–05±4.126E–06 Fed – kd:ko 0.88 0.95* 0.93 0.90 0.93 0.96* 0.91±0.02 a Fasted – kd:ko 1.08 0.96 1.02 1.09 1.37 0.94 1.07±0.16 b Fed – respirometry (kJ kg–1 day–1) 32.70 24.14* 33.80 23.98 24.17 22.86* 28.66±5.31 a Fed – DLW (kJ kg–1 day–1) 59.56 –8.76* 19.22 32.78 11.85 –8.06* 30.85±21.01 a Fasted – respirometry (kJ kg–1 day–1) 15.89 14.40 12.43 14.17 11.73 14.01 13.77±1.49 b Fasted – DLW (kJ kg–1 day–1) –65.80 –6.60 –34.19 –44.01 –130.35 1.63 –46.55±47.90 n/a Fed – RER 0.88 0.82 0.78 0.93 0.74 0.85 0.83±0.07 a Fast (10 days) – RER 0.58 0.60 0.24 0.46 0.50 0.78 0.53±0.18 b Fast (15 days) – RER 0.69 0.69 0.58 0.58 0.48 0.52 0.59±0.09 b Fed – breathing frequency 0.14 0.09 0.1 0.09 0.1 0.07 0.10±0.02 a Fasted – breathing frequency 0.11 0.06 0.09 0.08 0.06 0.12 0.09±0.03 a % TBW (2H) Fed 67.06 67.07 71.48 61.10 65.51 67.77 66.67±3.37 a Fasted (10 days) 59.48 62.49 66.37 48.18 50.59 65.07 58.70±7.63 b Fasted (15 days) 60.31 60.61 61.72 53.51 50.31 61.54 58.00±4.85 b Water turnover (I day–1) Fed 1.24 1.49 1.63 1.38 1.36 0.95 1.43±0.17 a Fasted (10 days) 0.79 0.86 0.75 0.69 0.83 0.76 0.78±0.06 b Fasted (15 days) 0.79 0.83 0.68 0.76 0.83 0.71 0.77±0.06 b Fed (21 days) 1.57 1.43 1.67 1.55 1.35 1.24 1.47±0.16 a Fed (25 days) 1.32 1.25 1.67 1.34 1.36 1.10 1.34±0.19 a % TBW day–1 Fed 9.21 8.86 11.53 8.68 8.40 7.08 9.57±1.33 a Fasted (10 days) 7.00 5.45 5.82 5.64 6.87 6.07 6.14±0.65 b Fasted (15 days) 6.94 5.48 5.83 5.68 6.86 6.07 6.14±0.62 b Fed (21 days) 13.74 9.46 14.34 11.52 11.14 10.65 11.81±1.87 c Fed (25 days) 9.82 7.47 11.79 8.41 8.35 8.25 9.02±1.56 a -
Mass for fasted turtles is the average between days 10 and 15; post-fast 21 days is 21 days from start of trial and so on. The DLW MRs are from Eqn 7, see Materials and methods
Mean ± s.d. and significant differences are given among related data groups (i.e. values within the lines of sig. diff. column). In the final column, letters (a,b,c) are used to denote significant differences. If the same letter is given then there is no difference, i.e. `a' is significantly different from `b' and `c' but not from another `a'. Values with an asterisk were not used in the determination of the mean
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- Fig. 3.
Natural log of isotopic enrichment above background levels used for doubly labeled water (DLW) metabolic measurements using the multiple-sample approach. (A) Washout during the fasting trials; (B) washout during fed trials. Solid lines are for 18O and broken lines for 2H.
- Table 2.
Body pool estimate (N) and doubly labelled water (DLW) derived metabolic rate (MR) for the seven equations listed in the methods section for the fed trials
Equation Pool(s) N (ml) MR (kJ kg–1 day–1) % diff. from resp. 1 1 15045.72±1508.41 53.07±20.98 85.17 2 1 15045.72±1508.41 66.91±21.56 133.46 3 2 Table 1 16.4±19.83 42.78 4 2 14996.96±1511.58 51.79±20.13 80.70 5 2 14902.35±1501.99 42.13±19.83 47.00 6 2 15045.72±1508.41 38.5±19.77 34.33 7 2 15045.72±1508.41 30.85±21.01 7.67 -
Values are means ± s.d. MRs are from the DLW two-sample technique (Speakman, 1997). Final column gives the absolute percent difference between the DLW-derived MR and the respirometry-derived MR. For Eqn 3, the body pool estimate (No and Nd) are used for each individual turtle and these can be found in Table 1
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