Metabolic response to feeding and fasting in the water python (Liasis fuscus)

2001 ◽  
Vol 49 (4) ◽  
pp. 379 ◽  
Author(s):  
Gavin S. Bedford ◽  
Keith A. Christian
Keyword(s):  
Metabolic Rate ◽  
Body Mass ◽  
Metabolic Response ◽  
Standard Metabolic Rate ◽  
Meal Size ◽  
Digestive Physiology ◽  
Small Prey ◽  
Feeding And Fasting

Compared with other reptiles, pythons have a relatively low standard metabolic rate (SMR) when post-absorptive, but metabolism increases substantially after feeding. This study examined the effects of feeding and fasting on adult and hatchling water pythons (Liasis fuscus). We compared ratios of peak digestive metabolic rate (PDMR) after feeding with the metabolic rate of both post-absorptive (SMR) and fasted water pythons. If metabolic rate of a fasting snake is taken as ‘SMR’, then the ratio PDMR/SMR becomes increasingly exaggerated as fasting continues. After 56 days of fasting in adults, or after 45 days in hatchlings, the metabolic rate of water pythons was significantly lower than that of post-absorptive animals. Peak digestive metabolic rate of post-absorptive adult water pythons was only 6.3–12.0 times SMR, but the ratio was twice that if fasted (metabolically depressed) animals were used to determine the ‘SMR’ denominator. Thus, this ratio should be used with caution. Peak digestive metabolic rate after feeding increased with increasing meal size for meals less than 20% of body mass, but PDMR did not increase for meals between 20% and 39% of body mass for adult water pythons. Similarly, the PDMR did not increase signif icantly between 25% and 50% meal sizes for hatchlings. The digestive physiology of water pythons is apparently better suited to frequent meals of relatively small prey compared with the digestive physiology of some other pythons.

Energetic costs of digestion in Australian crocodiles

2011 ◽  
Vol 59 (6) ◽  
pp. 416 ◽  
Author(s):  
C. M. Gienger ◽  
Christopher R. Tracy ◽  
Matthew L. Brien ◽  
S. Charlie Manolis ◽  
Grahame J. W. Webb ◽  
...  
Keyword(s):  
Body Size ◽  
Metabolic Rate ◽  
Body Mass ◽  
Rapid Growth ◽  
Metabolic Response ◽  
Standard Metabolic Rate ◽  
Specific Dynamic Action ◽  
Energetic Costs ◽  
Resting Metabolism ◽  
Crocodylus Porosus

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 24 h of feeding, a postfeeding metabolic peak (peak 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 25.96 kg body mass), SMR, peak 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.

Effect of sloughing and digestion on metabolic rate in the Australian carpet python, Morelia spilota imbricata

1999 ◽  
Vol 47 (6) ◽  
pp. 605 ◽  
Author(s):  
Graham G. Thompson ◽  
Philip C. Withers
Keyword(s):  
Metabolic Rate ◽  
Body Mass ◽  
Standard Metabolic Rate ◽  
Two Factors

The standard metabolic rate for juvenile carpet pythons, Morelia spilota imbricata, with a mean body mass of 129.6 g (range 57.7–253 g) increased from 6.75 ± 0.96 (s.e.) mL h–1 to 42.6 ± 12.40 (s.e.) mL h–1 in 48 h after ingesting mice equal to approximately 23% of their body mass, at a temperature of 30°C. Sloughing increased metabolic rate to approximately 146% of standard metabolic rate at 30°C. Metabolic rate is elevated before the eyes become opaque and other visual signs indicate that a slough is imminent. The implications of these two factors when measuring standard metabolic rate are discussed.

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