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Feeding History and Obese‐Prone Genotype Increase Survival of Rats Exposed to a Challenge of Food Restriction and Wheel Running
Author(s) -
Diane Abdoulaye,
Pierce W. David,
Heth C. Donald,
Russell James C.,
Richard Denis,
Proctor Spencer D.
Publication year - 2012
Publication title -
obesity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.438
H-Index - 199
eISSN - 1930-739X
pISSN - 1930-7381
DOI - 10.1038/oby.2011.326
Subject(s) - weight loss , medicine , endocrinology , obesity , starvation , body weight , diet induced obese , juvenile , zoology , biology , insulin resistance , genetics
We hypothesized that obese‐prone genotype and history of food restriction confer a survival advantage to genetically obese animals under environmental challenge. Male juvenile JCR:LA‐ cp rats, obese‐prone and lean‐prone, were exposed to 1.5 h daily meals and 22.5‐h voluntary wheel running, a procedure inducing activity anorexia (AA). One week before the AA challenge, obese‐prone rats were freely fed (obese‐FF), or pair fed (obese‐PF) to lean‐prone, free‐feeding rats (lean‐FF). Animals were removed from protocol at 75% of initial body weight (starvation criterion) or after 14 days (survival criterion). AA challenge induced weight loss in all rats, but percent weight loss was more rapid and sustained in lean‐FF rats than in obese‐FF or obese‐PF animals ( P < 0.04). Weight loss was significantly higher in obese‐FF rats than obese‐PF rats, 62% of which achieved survival criterion and stabilized with zero weight loss. Obese‐PF rats survived longer, on average (12.0 ± 1.1 day) than obese‐FF (8.2 ± 1.1 day) and lean‐FF rats (3.5 ± 0.2 day) ( P < 0.02). Wheel running increased linearly in all groups; lean‐FF increased more rapidly than obese‐FF ( P < 0.05); obese‐PF increased at an intermediate rate ( P < 0.02), and those rats that survived stabilized daily rates of wheel running. Prior food restriction of juvenile obese‐prone rats induces a survival benefit beyond genotype, that is related to achievement of homeostasis. This metabolic adaptive process may help explain the development of human obesity in the presence of an unstable food environment which subsequently transitions to an abundant food supply.