Gastric function and its contribution to the postprandial metabolic response of the Burmese pythonPython molurus

Abstract

SUMMARY The large intact prey ingested by Burmese pythons require considerable processing by the stomach before passage into the small intestine. To investigate the function and cost of gastric digestion and its contribution to postprandial metabolic response for the Burmese python, I examined the rate of gastric digestion, the postprandial profile of gastric pH and the effects of decreasing gastric workload on the metabolic cost of digestion, referred to as specific dynamic action (SDA). Ingested meal mass (equivalent to 25% of snake body mass) was reduced by 18% within 1 day postfeeding, by which time intragastric pH had decreased from 7.5 to 2. Gastric pH was maintained at 1.5 for the next 5–7 days, after which it returned to 7.5. The SDA generated by digesting an intact rat meal was reduced by 9.1%, 26.0%, 56.5% and 66.8%,respectively, when pythons were fed steak, ground rat, liquid diet or ground rat directly infused into the small intestine. The production of HCl and enzymes and other gastric functions represent an estimated 55% of the python's SDA generated from the digestion of an intact rodent meal. Additional contributors to SDA include protein synthesis (estimated 26%),gastrointestinal upregulation (estimated 5%) and the activities of the pancreas, gallbladder, liver, kidneys and intestines during digestion(estimated 14%). Operating on a `pay before pumping' principle, pythons must expend endogenous energy in order to initiate acid production and other digestive processes before ingested nutrients can be absorbed and channeled into metabolic pathways.

Postprandial morphological response of the intestinal epithelium of the Burmese python (Python molurus)

“…Enterocyte width and volume continued to increase during digestion, before peaking at day 6 when digestion was close to completion (Secor, 2003). During this time, the villi experienced several structural changes; longitudinal cracks appear along the villus edges by day 3 and then largely disappear by day 6.…”

The energetic significance of cooking

“…In other animals the cost of digesting food is reduced when its physical structure is more easily broken down. It has been shown among reptiles and amphibians that food items that are softer induce a lower cost of digestion (Secor and Faulkner, 2002;Secor, 2003;Secor and Boehm, 2006;Boback et al, 2007). For example, Secor and Faulkner (2002) compared the metabolic costs of digestion among marine toads (Bufo marinus) fed meals that differed in hardness.…”

“…For example, pythons typically ingest their meals whole, necessitating greater gastric effort to break down meals into a soup-like chyme suitable for passage into the small intestine (Secor, 2003). In addition, pythons, unlike humans, exhibit substantial gastrointestinal remodeling between meals Diamond 1995, 1997).…”

Fisiologia De Extremos: Digestão Em Répteis De Alimentação Esporádica

“…Por outro lado, em não-mamíferos, um único tipo celular é responsável pela secreção do pepsinogênio e do HCl. As ações digestivas do estômago reduzem as partículas alimentares a uma solução conhecida como quimo (SECOR, 2003;WIDMAIER;RAFF;STRANG, 2006;TAYLOR;GROSELL, 2012).…”