Limits to sustained energy intake. XXX: Constraint or restraint? Manipulations of food supply show peak food intake in lactation is constrained

Zhi Jun Zhao* (Corresponding Author), Davina Derous, Abby Gerard, Jing Wen, Xue Liu, Song Tan, Catherine Hambly, John Speakman* (Corresponding Author)

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)
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Abstract

Lactating mice increase food intake 4- to 5-fold, reaching an asymptote in late lactation. A key question is whether this asymptote reflects a physiological constraint, or a maternal investment strategy (a ‘restraint’). We exposed lactating mice to periods of food restriction, hypothesizing that if the limit reflected restraint, they would compensate by breaching the asymptote when refeeding. In contrast, if it was a constraint, they would by definition be unable to increase their intake on refeeding days. Using isotope methods, we found that during food restriction, the females shut down milk production, impacting offspring growth. During refeeding, food intake and milk production rose again, but not significantly above unrestricted controls. These data provide strong evidence that asymptotic intake in lactation reflects a physiological/physical constraint, rather than restraint. Because hypothalamic neuropeptide Y (Npy) was upregulated under both states of restriction, this suggests the constraint is not imposed by limits in the capacity to upregulate hunger signalling (the saturated neural capacity hypothesis). Understanding the genetic basis of the constraint will be a key future goal and will provide us additional information on the nature of the constraining factors on reproductive output, and their potential links to life history strategies.

Original languageEnglish
Article numberjeb208314
Number of pages19
JournalJournal of Experimental Biology
Volume223
Issue number8
Early online date16 Apr 2020
DOIs
Publication statusPublished - Apr 2020

Bibliographical note

This work was partly supported by grants (No. 31670417, 31870388) from the National Natural Science Foundation of China and the Chinese Academy of Sciences Strategic program (XDB13030100).

All data is available in the main text or the supplementary materials. Additional data related to this paper may be requested from the authors. Requests should be addressed to Z.J.Z. and J.R.S

Keywords

  • food restriction
  • daily energy intake (DEI)
  • heat dissipation limit (HDL) theory
  • milk energy output (MEO)
  • gene expression profile
  • hunger signaling
  • peripheral limitation
  • Swiss mice
  • neuropeptide Y
  • RNAseq
  • Neuropeptide Y
  • Daily energy intake (DEI)
  • Food restriction
  • Heat dissipation limit (HDL) theory
  • Gene expression profile
  • Peripheral limitation
  • Hunger signalling
  • Milk energy output (MEO)
  • SHORT-TERM CALORIE
  • GENE-EXPRESSION
  • METABOLIC-RATE
  • LABORATORY MICE
  • PROTEIN RESTRICTION
  • HEAT DISSIPATION CAPACITY
  • BODY-TEMPERATURE
  • BRANDTS VOLES
  • PHYSICAL-ACTIVITY
  • GRADED-LEVELS

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