Abstract
Oxidative stress is a potential proximal physiological cost of reproduction. Detecting this cost may be performed in several different ways - manipulating reproductive status, correlating natural variations in effort to oxidative stress or manipulating reproductive effort. Here, we manipulated reproductive status and studied oxidative stress due to natural and experimental variation in reproductive effort in Brandt's voles (Lasiopodomys brandtii), using a variety of markers and tissues.
We measured markers of oxidative stress in lactating (raising 6 to 8 offspring) and non-reproductive voles (Experiment I) and found that a marker of oxidative protection [serum total-superoxide dismutase (SOD) activity] was reduced, and a marker of oxidative damage (protein carbonyls) was increased, in the serum, in lactating compared with non-reproductive voles. However, protein carbonyls in the liver were lower in lactating compared with non-reproductive voles, consistent with increased liver SOD activity. Lipid damage [malonaldehyde (MDA)] in both serum and liver was unrelated to reproductive status.
We compared these markers of oxidative stress between natural large (n ≥ 9) and small litter sizes (n ≤ 5; Experiment II), and between manipulated large (11-13) and small litter sizes (2-3; Experiment III) and found that liver MDA and SOD activity was higher in voles with natural large compared with natural small litter sizes, but there were no differences in other markers. There was no effect of litter size on all measures when it was experimentally manipulated.
The effects of reproductive status on oxidative stress were critically dependent on the exact markers and tissues used. The effects of natural variation in reproductive effort suggested that there might be an oxidative stress cost associated with large litter sizes, but this effect was not replicated in the experimentally manipulated litters.
| Original language | English |
|---|---|
| Pages (from-to) | 402-410 |
| Number of pages | 9 |
| Journal | Functional Ecology |
| Volume | 28 |
| Issue number | 2 |
| Early online date | 15 Mar 2014 |
| DOIs | |
| Publication status | Published - Apr 2014 |
Bibliographical note
We thank all the members of Animal Physiological Ecology Group for their assistance. This study was supported by Grants from National Natural Science Foundation of China (31272312 and 31071930) and Chinese Academy of Sciences (KSCX2-EW-N-005) to DHW. J.R.S. was supported by a ‘1000 talents’ professorship and a ‘Great wall’ professorship from the Chinese Academy of Sciences – Novo-Nordisk Foundation. We thank two anonymous referees and the associate editor for their helpful and constructive comments which improved the manuscript.Keywords
- Brandt's vole (Lasiopodomys brandtii)
- Lactation
- Life-history trade-offs
- Litter size
- Oxidative damage