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Science Forum Index » Life Extension Forum » The impact of dietary restriction, intermittent...
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 Posted: Wed May 14, 2008 12:03 pm |
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Proc Biol Sci. 2008 Apr 29 [Epub ahead of print] Links
The impact of dietary restriction, intermittent feeding and
compensatory growth on reproductive investment and lifespan in a short-
lived fish.Inness CL, Metcalfe NB.
Fish Biology Group, Division of Environmental & Evolutionary Biology,
Graham Kerr Building, IBLS, University of Glasgow, Glasgow G12 8QQ,
UK.
While dietary restriction usually increases lifespan, an intermittent
feeding regime, where periods of deprivation alternate with times when
food is available, has been found to reduce lifespan in some studies
but prolong it in others. We suggest that these disparities arise
because in some situations lifespan is reduced by the costs of catch-
up growth (following the deprivation) and reproductive investment, a
factor that has rarely been measured in studies of lifespan. Using
three-spined sticklebacks, we show for the first time that while
animals subjected to an intermittent feeding regime can grow as large
as continuously fed controls that receive the same total amount of
food, and can maintain reproductive investment, they have a shorter
lifespan. Furthermore, we show that this reduction in lifespan is
linked to rapid skeletal growth rate and is due to an increase in the
instantaneous risk of mortality rather than in the rate of senescence.
By contrast, dietary restriction caused a reduction in reproductive
investment in females but no corresponding increase in longevity. This
suggests that in short-lived species where reproduction is size
dependent, selection pressures may lead to an increase in intrinsic
mortality risk when resources are diverted from somatic maintenance to
both growth and reproductive investment.
PMID: 18445563 [PubMed - as supplied by publisher] |
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