Energetic costs of digestion in Australian crocodiles

C. M. Gienger; Christopher R. Tracy; Matthew L. Brien; S. Charlie Manolis; Grahame J W Webb; Roger S. Seymour; Keith A. Christian

doi:10.1071/ZO12018

Energetic costs of digestion in Australian crocodiles

C. M. Gienger, Christopher R. Tracy, Matthew L. Brien, S. Charlie Manolis, Grahame J W Webb, Roger S. Seymour, Keith A. Christian

Research output: Contribution to journal › Article › peer-review

9 Citations (Scopus)

Abstract

We measured standard metabolic rate (SMR) and the metabolic response to feeding in the Australian crocodiles, Crocodylus porosus and C. johnsoni. Both species exhibit a response that is characterised by rapidly increasing metabolism that peaks within 24h of feeding, a postfeeding metabolic peak (peak V̇_O2) of 1.4-2.0 times SMR, and a return to baseline metabolism within 3-4 days after feeding. Postfeeding metabolism does not significantly differ between species, and crocodiles fed intact meals have higher total digestive costs (specific dynamic action; SDA) than those fed homogenised meals. Across a more than 100-fold range of body size (0.190 to 25.96kg body mass), SMR, peak V̇_O2, and SDA all scale with body mass to an exponent of 0.85. Hatchling (≤1 year old) C. porosus have unexpectedly high rates of resting metabolism, and this likely reflects the substantial energetic demands that accompany the rapid growth of young crocodilians.

Original language	English
Pages (from-to)	416-421
Number of pages	6
Journal	Australian Journal of Zoology
Volume	59
Issue number	6
DOIs	https://doi.org/10.1071/ZO12018
Publication status	Published - 2012

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title = "Energetic costs of digestion in Australian crocodiles",

abstract = "We measured standard metabolic rate (SMR) and the metabolic response to feeding in the Australian crocodiles, Crocodylus porosus and C. johnsoni. Both species exhibit a response that is characterised by rapidly increasing metabolism that peaks within 24h of feeding, a postfeeding metabolic peak (peak {\.V}O2) of 1.4-2.0 times SMR, and a return to baseline metabolism within 3-4 days after feeding. Postfeeding metabolism does not significantly differ between species, and crocodiles fed intact meals have higher total digestive costs (specific dynamic action; SDA) than those fed homogenised meals. Across a more than 100-fold range of body size (0.190 to 25.96kg body mass), SMR, peak {\.V}O2, and SDA all scale with body mass to an exponent of 0.85. Hatchling (≤1 year old) C. porosus have unexpectedly high rates of resting metabolism, and this likely reflects the substantial energetic demands that accompany the rapid growth of young crocodilians. ",

keywords = "bioenergetics, body mass, body size, crocodilian, food intake, growth rate, metabolism, Crocodylidae (all crocodiles), Crocodylus porosus",

author = "Gienger, {C. M.} and Tracy, {Christopher R.} and Brien, {Matthew L.} and Manolis, {S. Charlie} and Webb, {Grahame J W} and Seymour, {Roger S.} and Christian, {Keith A.}",

year = "2012",

doi = "10.1071/ZO12018",

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T1 - Energetic costs of digestion in Australian crocodiles

AU - Gienger, C. M.

AU - Tracy, Christopher R.

AU - Brien, Matthew L.

AU - Manolis, S. Charlie

AU - Webb, Grahame J W

AU - Seymour, Roger S.

AU - Christian, Keith A.

PY - 2012

Y1 - 2012

N2 - We measured standard metabolic rate (SMR) and the metabolic response to feeding in the Australian crocodiles, Crocodylus porosus and C. johnsoni. Both species exhibit a response that is characterised by rapidly increasing metabolism that peaks within 24h of feeding, a postfeeding metabolic peak (peak V̇O2) of 1.4-2.0 times SMR, and a return to baseline metabolism within 3-4 days after feeding. Postfeeding metabolism does not significantly differ between species, and crocodiles fed intact meals have higher total digestive costs (specific dynamic action; SDA) than those fed homogenised meals. Across a more than 100-fold range of body size (0.190 to 25.96kg body mass), SMR, peak V̇O2, and SDA all scale with body mass to an exponent of 0.85. Hatchling (≤1 year old) C. porosus have unexpectedly high rates of resting metabolism, and this likely reflects the substantial energetic demands that accompany the rapid growth of young crocodilians.

AB - We measured standard metabolic rate (SMR) and the metabolic response to feeding in the Australian crocodiles, Crocodylus porosus and C. johnsoni. Both species exhibit a response that is characterised by rapidly increasing metabolism that peaks within 24h of feeding, a postfeeding metabolic peak (peak V̇O2) of 1.4-2.0 times SMR, and a return to baseline metabolism within 3-4 days after feeding. Postfeeding metabolism does not significantly differ between species, and crocodiles fed intact meals have higher total digestive costs (specific dynamic action; SDA) than those fed homogenised meals. Across a more than 100-fold range of body size (0.190 to 25.96kg body mass), SMR, peak V̇O2, and SDA all scale with body mass to an exponent of 0.85. Hatchling (≤1 year old) C. porosus have unexpectedly high rates of resting metabolism, and this likely reflects the substantial energetic demands that accompany the rapid growth of young crocodilians.

KW - bioenergetics

KW - body mass

KW - body size

KW - crocodilian

KW - food intake

KW - growth rate

KW - metabolism

KW - Crocodylidae (all crocodiles)

KW - Crocodylus porosus

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U2 - 10.1071/ZO12018

DO - 10.1071/ZO12018

M3 - Article

SN - 0004-959X

VL - 59

SP - 416

EP - 421

JO - Australian Journal of Zoology

JF - Australian Journal of Zoology

IS - 6

ER -

Energetic costs of digestion in Australian crocodiles

Abstract

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