title: The oxidative debt of fasting: evidence for short- to medium-term costs of advanced fasting in adult king penguins.
abstract: In response to prolonged periods of fasting, animals have evolved metabolic adaptations helping to mobilize body reserves and/or reduce metabolic rate to ensure a longer usage of reserves. However, those metabolic changes can be associated with higher exposure to oxidative stress, raising the question of how species that naturally fast during their life cycle avoid an accumulation of oxidative damage over time. King penguins repeatedly cope with fasting periods of up to several weeks. Here, we investigated how adult male penguins deal with oxidative stress after an experimentally induced moderate fasting period (PII) or an advanced fasting period (PIII). After fasting in captivity, birds were released to forage at sea. We measured plasmatic oxidative stress on the same individuals at the start and end of the fasting period and when they returned from foraging at sea. We found an increase in activity of the antioxidant enzyme superoxide dismutase along with fasting. However, PIII individuals showed higher oxidative damage at the end of the fast compared with PII individuals. When they returned from re-feeding at sea, all birds had recovered their initial body mass and exhibited low levels of oxidative damage. Notably, levels of oxidative damage after the foraging trip were correlated to the rate of mass gain at sea in PIII individuals but not in PII individuals. Altogether, our results suggest that fasting induces a transitory exposure to oxidative stress and that effort to recover in body mass after an advanced fasting period may be a neglected carryover cost of fasting.
authors: IPHC, UNISTRA, CNRS, 23 rue du Loess, 67200 Strasbourg, France quentin.schull@gmail.com.
authors: Quentin
authors: 0000-0001-9297-3376
authors: Q
authors: Schull
authors: IPHC, UNISTRA, CNRS, 23 rue du Loess, 67200 Strasbourg, France.
authors: Vincent A
authors: VA
authors: Viblanc
authors: IPHC, UNISTRA, CNRS, 23 rue du Loess, 67200 Strasbourg, France.
authors: Antoine
authors: A
authors: Stier
authors: IPHC, UNISTRA, CNRS, 23 rue du Loess, 67200 Strasbourg, France.
authors: Hédi
authors: H
authors: Saadaoui
authors: IPHC, UNISTRA, CNRS, 23 rue du Loess, 67200 Strasbourg, France.
authors: Emilie
authors: E
authors: Lefol
authors: IPHC, UNISTRA, CNRS, 23 rue du Loess, 67200 Strasbourg, France.
authors: François
authors: F
authors: Criscuolo
authors: Institute of Biological and Environmental Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen AB24 2TZ, UK.
authors: Pierre
authors: P
authors: Bize
authors: IPHC, UNISTRA, CNRS, 23 rue du Loess, 67200 Strasbourg, France.
authors: Jean-Patrice
authors: JP
authors: Robin
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001835:Body Weight; D005215:Fasting / Q000097:blood / Q000502:physiology*; D005247:Feeding Behavior; D016014:Linear Models; D009792:Oceans and Seas; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000097:blood; D046429:Spheniscidae / Q000097:blood / Q000502:physiology*; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D000975:Antioxidants; D017382:Reactive Oxygen Species; D013482:Superoxide Dismutase
keywords: Foraging effort; Hormesis; Oxidative stress; Re-feeding signal