King penguin biology is characterized by an exceptionally long
breeding cycle during which the chicks exhibit a terrestrial growing
phase of longer than one year. During the austral winter, king penguin
chicks are infrequently fed by their parents and usually undergo severe
food deprivation. (Credit: Pierre-Axel Monternier)
July 2, 2013 — King penguin
chicks survive harsh winters with almost no food by minimising the cost
of energy production. A new study, to be presented at the Society for
Experimental Biology meeting in Valencia on the 3rd July, shows that the
efficiency of the mitochondria, the power house of the cell, is
increased in fasted king penguin chicks.
King penguin chicks are socially and morphologically well adapted to
harsh environmental conditions, however, they experience a severe energy
challenge during the cold sub-Antarctic winter, when food is not
readily available. Research headed by Pierre-Axel Monternier and Prof
Damien Roussel at the Ecology of Natural and Man-impacted Hydrosystems
laboratory in France looked, for the first time, at how the king penguin
chicks' mitochondria in skeletal muscle, the main heat producing tissue
in birds, function during fasting in the winter.
Pierre-Axel Monternier said: "We found that the efficiency of mitochondrial functioning increased in fasted winter-acclimatized king penguin chicks. This indicates that less substrate/oxygen was consumed to produce the same amount of energy in the form of ATP, showing that mitochondria from fasted chicks adjust its functioning to minimize the cost of energy production."
This study shows how king penguins are able to produce heat to survive the cold without depleting their energy stores, an essential mechanism to survive the cold when food is scarce. Their biological adjustments increase survival of chicks, which, among birds, have an unrivalled fasting endurance (up to 5 months).
Fasting in the cold represents a bioenergetics trade-off between sparing energy for body maintenance and dissipating energy for heat production and endothermy maintenance. In this challenging context, chicks develop a whole range of energy sparing mechanisms (social huddling behaviour, reduction in muscle activity and basal metabolic rate, short period of hypothermia and high thermal insulation) that lead to reduce the energy allocated to heat production and growth.
Pierre-Axel Monternier said: "We found that the efficiency of mitochondrial functioning increased in fasted winter-acclimatized king penguin chicks. This indicates that less substrate/oxygen was consumed to produce the same amount of energy in the form of ATP, showing that mitochondria from fasted chicks adjust its functioning to minimize the cost of energy production."
This study shows how king penguins are able to produce heat to survive the cold without depleting their energy stores, an essential mechanism to survive the cold when food is scarce. Their biological adjustments increase survival of chicks, which, among birds, have an unrivalled fasting endurance (up to 5 months).
Fasting in the cold represents a bioenergetics trade-off between sparing energy for body maintenance and dissipating energy for heat production and endothermy maintenance. In this challenging context, chicks develop a whole range of energy sparing mechanisms (social huddling behaviour, reduction in muscle activity and basal metabolic rate, short period of hypothermia and high thermal insulation) that lead to reduce the energy allocated to heat production and growth.
Story Source:
The above story is reprinted from materials provided by Society for Experimental Biology, via EurekAlert!, a service of AAAS.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Society for Experimental Biology (2013, July 2). Surviving fasting in the cold. ScienceDaily. Retrieved July 3, 2013, from http://www.sciencedaily.com /releases/2013/07/130702202903.htm
No comments:
Post a Comment