First published online January 25, 2005
Journal of Experimental Biology 208, 571-584 (2005)
Published by The Company of Biologists 2005
doi: 10.1242/jeb.01429
Effect of photoperiod on body mass, food intake and body composition in the field vole, Microtus agrestis
E. Król1,*,
P. Redman1,
P. J. Thomson1,
R. Williams1,
C. Mayer2,
J. G. Mercer3 and
J. R. Speakman1,3
1 Aberdeen Centre for Energy Regulation and Obesity (ACERO), School of
Biological Sciences, Zoology Building, University of Aberdeen, Aberdeen AB24
2TZ, UK
2 BioSS Office, Rowett Research Institute, Bucksburn, Aberdeen AB21 9SB,
UK
3 ACERO, Division of Energy Balance and Obesity, Rowett Research
Institute, Bucksburn, Aberdeen AB21 9SB, UK
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Fig. 1. Effect of exposure to long day photoperiod (LD, 16 h:8 h L:D) on mean body
mass (A) and food intake (B) of 12 male field voles measured between days
–24 and 56 (day 0 is the day of exposure to LD). Data for 11 voles kept
in short day photoperiod (SD, 8 h:16 h L:D) are also shown. Error bars
indicate 1 S.D.
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Fig. 2. Food intake (A) and metabolizable energy intake (B) as a function of body
mass for 12 male field voles prior to exposure to long day photoperiod (LD, 16
h:8 h L:D), during the increase phase (days 1–28 of LD exposure) and
during the plateau phase (days 29–56 of LD exposure). Prior to exposure
to LD, the animals were kept in short day photoperiod (SD, 8 h:16 h L:D). The
measurements of food intake were repeated three times during the pre-exposure
phase and four times during the increase and plateau phases. After adjusting
for differences in body mass, photoperiod had no effect on food intake, but it
did have a significant effect on MEI (for statistical details, see Results).
The relationships are described by y=27.7+2.0x for
pre-exposure, y=26.0+2.4x for LD increase and
y=30.4+2.2x for LD plateau.
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Fig. 3. Body mass (A), dry fat mass (B), dry lean mass (C) and body water mass (D)
in male field voles exposed to short day photoperiod (SD, 8 h:16 h L:D,
N=38) and long day photoperiod (LD, 16 h:8 h L:D) for 1–28 days
(the increase phase, N=20) or 29–70 days (the plateau phase,
N=25). Dry fat mass was calculated as the sum of subcutaneous,
epididymal, perirenal, retroperitoneal and mesenteric fat depots. Bars are
means + 1 S.D. Different letters above bars indicate significant
differences between the groups, as assessed by one-way ANOVA followed by Tukey
pairwise comparisons.
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Fig. 4. Dry mass of subcutaneous, epididymal, perirenal, retroperitoneal and
mesenteric fat depots as a function of body mass for male field voles exposed
to short day photoperiod (SD, 8 h:16 h L:D, N=38) and long day
photoperiod (LD, 16 h:8 h L:D) for 1–28 days (the increase phase,
N=20) or 29–70 days (the plateau phase, N=25). After
adjusting for the differences in body mass, the differences in dry fat mass
between the three groups of voles were not significant (for statistical
details, see Results).
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Fig. 5. Dry mass of gonads (testes and seminal vesicles) as a function of body mass
for male field voles exposed to short day photoperiod (SD, 8 h:16 h L:D,
N=38) and long day photoperiod (LD, 16 h:8 h L:D) for 1–28 days
(the increase phase, N=20) or 29–70 days (the plateau phase,
N=25). The relationships are described by
y=–0.097+0.009x for SD,
y=–0.146+0.012x for LD increase and
y=0.152+0.006x for LD plateau (for statistical details, see
Results).
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© The Company of Biologists Ltd 2005
