Well, copied and pasted abstracts. These can be found on pubmed for anyone whos interested in doing their own search, or wants to read the entire research article.



Physiol Zool. 1997 Mar-Apr;70(2):202-12.



Determinants of the postfeeding metabolic response of Burmese pythons, Python molurus.



Secor SM, Diamond J.



Department of Physiology, School of Medicine, University of California, Los Angeles 90095-1751, USA.



The relatively large meal sizes consumed by sit-and-wait-foraging snake species make them favorable for investigating specific dynamic action, the rise in metabolic rate associated with digestion. Hence, we measured O2 consumption rates (VO2) before and up to 20 d after Burmese pythons (Python molurus) either had only constricted and killed rodent meals or had also been allowed to consume meals ranging in size from 5% to 111% of their body mass. Postprandial VO2 peaked within 2 d at a value that increased with meal size, up to 44 times standard metabolic rate for the largest meals. In addition to being the largest known magnitude of postprandial metabolic response, this also exceeds the factorial increase in VO2 during peak physical activity for all studied animals except perhaps racehorses. Specific dynamic action, calculated from the extra VO2 above standard metabolic rate over the duration of digestion, increased with meal size and equaled 32% of ingested meal energy. The allometric exponent for body mass was 0.68 for standard metabolic rate, 0.90 for peak postprandial VO2, and 1.01 for specific dynamic action. Specific dynamic action is higher, and standard metabolic rate is lower, in sit-and-wait-foraging snake species than in actively foraging snake species. This suggests that sit-and-wait-foraging snakes, which consume large meals at long and unpredictable intervals, reduce standard metabolic rate by allowing the energetically expensive small intestine and other associated organs to atrophy between meals but thereby incur a large specific dynamic action while rebuilding those organs upon feeding.



1: Physiol Biochem Zool. 2002 Jul-Aug;75(4):360-8.

The effects of fasting duration on the metabolic response to feeding in Python molurus: an evaluation of the energetic costs associated with gastrointestinal growth and upregulation.



Overgaard J, Andersen JB, Wang T.



Department of Zoophysiology, Institute of Biology, Building 131, Aarhus University, Denmark. Johannes.Overgaard@biology.au.dk



The oxygen uptake of Python molurus increases enormously following feeding, and the elevated metabolism coincides with rapid growth of the gastrointestinal organs. There are opposing views regarding the energetic costs of the gastrointestinal hypertrophy, and this study concerns the metabolic response to feeding after fasting periods of different duration. Since mass and function of the gastrointestinal organs remain elevated for several days after feeding, the metabolic increment following a second meal given soon after the first can reveal whether the metabolic costs relate to the upregulation of gastrointestinal organs or merely the metabolic cost of processing a meal. Eight juvenile pythons were kept on a regular feeding regime for 6 mo after hatching. At the beginning of the metabolic measurements, they were fed mice (20% of body mass), and the metabolic response to similarly sized meals was determined following 3, 5, 7, 14, 21, 30, and 60 d of fasting. Our data show that the metabolic response following feeding was large, ranging from 21% to 35% of ingested energy (mean=27%), but the metabolic response seems independent of fasting duration. Hence, the extraordinarily large cost of digestion in P. molurus does not appear to correlate with increased function and growth of gastrointestinal organs but must be associated with other physiological processes.



Am J Physiol. 1997 Mar;272(3 Pt 2):R902-12.

Effects of meal size on postprandial responses in juvenile Burmese pythons (Python molurus).



Secor SM, Diamond J.



Department of Physiology, University of California, Los Angeles, School of Medicine, 90095-1751, USA.



Pythons were reported previously to exhibit large changes in intestinal mass and transporter activities on consuming meals equal to 25% of the snake's body mass. This paper examines how those and other adaptive responses to feeding vary with meal size (5, 25, or 65% of body mass). Larger meals took longer to pass through the stomach and small intestine. After ingestion of a meal, O2 consumption rates rose to up to 32 times fasting levels and remained significantly elevated for up to 13 days. This specific dynamic action equaled 29-36% of ingested energy. After 25 and 65% size meals, plasma Cl- significantly dropped, whereas plasma CO2, glucose, creatinine, and urea nitrogen increased as much as a factor of 2.3-4.2. Within 1 day the intestinal mucosal mass more than doubled, and masses of the intestinal serosa, liver, stomach, pancreas, and kidneys also increased. Intestinal uptake rates of amino acids and of D-glucose increased by up to 43 times fasting levels, whereas uptake capacities increased by up to 59 times fasting levels. Magnitudes of many of these responses (O2 consumption rate, kidney hypertrophy, and D-glucose and L-lysine uptake) increased with meal size up to the largest meals studied; other responses (Na+-independent L-leucine uptake, plasma Cl-, and organ masses) plateaued at meals equal to 25% of the snake's body mass; and still other responses (nutrient uptake at day 1, passive glucose uptake, and plasma protein and alkaline phosphatase) were all-or-nothing, being independent of meal size between 5 and 65% of body mass. Pythons undergo a wide array of postprandial responses, many of which differ in their sensitivity to meal size.



Basically... in the shortrun pythons don't seem to gain anything by eating smaller meals or larger meals. They expend the same amount of energy upregulating their digestive tissues becaues THAT IS HOW THEY ARE PROGRAMED.



I would be curious how much snakes are fed (as in grams per month) between the two differnt feeding strategies. Since physiological studies don't seem to point out why asf's snakes grow faster, I wonder if it really is just feeding more mass per month.

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