Abstract
Maximal sustained energy intake (SusEI) appears limited, but the factors imposing the limit are disputed. We studied reproductive performance in two lines of mice selected for high and low food intake (MH and ML, respectively), and known to have large differences in thermal conductance (29% higher in the MH line at 21 degrees C). When these mice raised their natural litters, their metabolisable energy intake significantly increased over the first 13 days of lactation and then reached a plateau. At peak lactation, MH mice assimilated on average 45.3% more energy than ML mice (222.9 +/- 7.1 and 153.4 +/- 12.5 kJ day(-1), N=49 and 24, respectively). Moreover, MH mice exported on average 62.3 kJ day(-1) more energy as milk than ML mice (118.9 +/- 5.3 and 56.6 +/- 5.4 kJ day(-1), N=subset of 32 and 21, respectively). The elevated milk production of MH mice enabled them to wean litters (65.2 +/- 2.1 g) that were on average 50.2% heavier than litters produced by ML mothers (43.4 +/- 3.0 g), and pups that were on average 27.2% heavier (9.9 +/- 0.2 and 7.8 +/- 0.2 g, respectively). Lactating mice in both lines had significantly longer and heavier guts compared with non-reproductive mice. However, inconsistent with the 'central limit hypothesis', the ML mice had significantly longer and heavier intestines than MH mice. An experiment where the mice raised litters of the opposing line demonstrated that lactation performance was not limited by the growth capacity of offspring. Our findings are consistent with the idea that the SusEI at peak lactation is constrained by the capacity of the mothers to dissipate body heat.
| Original language | English |
|---|---|
| Pages (from-to) | 3718-3732 |
| Number of pages | 15 |
| Journal | Journal of Experimental Biology |
| Volume | 217 |
| Issue number | 20 |
| Early online date | 11 Sep 2014 |
| DOIs | |
| Publication status | Published - Oct 2014 |
Keywords
- artificial selection
- cross-fostering
- daily energy expenditure
- heat dissipation limit
- milk production
- lactation
- doubly-labeled water
- dissipation limitation hypothesis
- resting metabolic-rate
- voles lasiopodomys-brandtii
- carbon-dioxide production
- lactating European hares
- mus-musculus
- laboratory mice
- food-intake
- divergent selection
Cite this
Limits to sustained energy intake. XXII. Reproductive performance of two selected mouse lines with different thermal conductance. / Al Jothery, Aqeel H.; Krol, Elzbieta; Hawkins, James; Chetoui, Aurore; Saint-Lambert, Alexander; Gamo, Yuko; Shaw, Suzanne C.; Valencak, Teresa; Buenger, Lutz; Hill, William G.; Vaanholt, Lobke M.; Hambly, Catherine; Speakman, John R.
In: Journal of Experimental Biology, Vol. 217, No. 20, 10.2014, p. 3718-3732.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Limits to sustained energy intake. XXII. Reproductive performance of two selected mouse lines with different thermal conductance
AU - Al Jothery, Aqeel H.
AU - Krol, Elzbieta
AU - Hawkins, James
AU - Chetoui, Aurore
AU - Saint-Lambert, Alexander
AU - Gamo, Yuko
AU - Shaw, Suzanne C.
AU - Valencak, Teresa
AU - Buenger, Lutz
AU - Hill, William G.
AU - Vaanholt, Lobke M.
AU - Hambly, Catherine
AU - Speakman, John R.
N1 - Acknowledgements We are grateful to the animal house staff who looked after the mice. Peter Thomson provided invaluable technical support for the isotope analysis. Funding The mice were selected under grants from BBSRC to W.G.H. and L.B., who was additionally supported by Cotswold International. A.H.A.J. was supported by a scholarship from the Iraqi government. A.C. and A.S.L. were supported by the Erasmus program and Y.G. was supported by a scholarship from the international rotary foundation. The work was also partly funded by research grants from NERC to J.R.S. and C.H. and from BBSRC to J.R.S. and E.K. J.R.S. was also supported by a 1000 Talents professorship during the final phase of the work.
PY - 2014/10
Y1 - 2014/10
N2 - Maximal sustained energy intake (SusEI) appears limited, but the factors imposing the limit are disputed. We studied reproductive performance in two lines of mice selected for high and low food intake (MH and ML, respectively), and known to have large differences in thermal conductance (29% higher in the MH line at 21 degrees C). When these mice raised their natural litters, their metabolisable energy intake significantly increased over the first 13 days of lactation and then reached a plateau. At peak lactation, MH mice assimilated on average 45.3% more energy than ML mice (222.9 +/- 7.1 and 153.4 +/- 12.5 kJ day(-1), N=49 and 24, respectively). Moreover, MH mice exported on average 62.3 kJ day(-1) more energy as milk than ML mice (118.9 +/- 5.3 and 56.6 +/- 5.4 kJ day(-1), N=subset of 32 and 21, respectively). The elevated milk production of MH mice enabled them to wean litters (65.2 +/- 2.1 g) that were on average 50.2% heavier than litters produced by ML mothers (43.4 +/- 3.0 g), and pups that were on average 27.2% heavier (9.9 +/- 0.2 and 7.8 +/- 0.2 g, respectively). Lactating mice in both lines had significantly longer and heavier guts compared with non-reproductive mice. However, inconsistent with the 'central limit hypothesis', the ML mice had significantly longer and heavier intestines than MH mice. An experiment where the mice raised litters of the opposing line demonstrated that lactation performance was not limited by the growth capacity of offspring. Our findings are consistent with the idea that the SusEI at peak lactation is constrained by the capacity of the mothers to dissipate body heat.
AB - Maximal sustained energy intake (SusEI) appears limited, but the factors imposing the limit are disputed. We studied reproductive performance in two lines of mice selected for high and low food intake (MH and ML, respectively), and known to have large differences in thermal conductance (29% higher in the MH line at 21 degrees C). When these mice raised their natural litters, their metabolisable energy intake significantly increased over the first 13 days of lactation and then reached a plateau. At peak lactation, MH mice assimilated on average 45.3% more energy than ML mice (222.9 +/- 7.1 and 153.4 +/- 12.5 kJ day(-1), N=49 and 24, respectively). Moreover, MH mice exported on average 62.3 kJ day(-1) more energy as milk than ML mice (118.9 +/- 5.3 and 56.6 +/- 5.4 kJ day(-1), N=subset of 32 and 21, respectively). The elevated milk production of MH mice enabled them to wean litters (65.2 +/- 2.1 g) that were on average 50.2% heavier than litters produced by ML mothers (43.4 +/- 3.0 g), and pups that were on average 27.2% heavier (9.9 +/- 0.2 and 7.8 +/- 0.2 g, respectively). Lactating mice in both lines had significantly longer and heavier guts compared with non-reproductive mice. However, inconsistent with the 'central limit hypothesis', the ML mice had significantly longer and heavier intestines than MH mice. An experiment where the mice raised litters of the opposing line demonstrated that lactation performance was not limited by the growth capacity of offspring. Our findings are consistent with the idea that the SusEI at peak lactation is constrained by the capacity of the mothers to dissipate body heat.
KW - artificial selection
KW - cross-fostering
KW - daily energy expenditure
KW - heat dissipation limit
KW - milk production
KW - lactation
KW - doubly-labeled water
KW - dissipation limitation hypothesis
KW - resting metabolic-rate
KW - voles lasiopodomys-brandtii
KW - carbon-dioxide production
KW - lactating European hares
KW - mus-musculus
KW - laboratory mice
KW - food-intake
KW - divergent selection
U2 - 10.1242/jeb.103705
DO - 10.1242/jeb.103705
M3 - Article
VL - 217
SP - 3718
EP - 3732
JO - Journal of Experimental Biology
JF - Journal of Experimental Biology
SN - 0022-0949
IS - 20
ER -