The effects of feeding on cell morphology and proliferation of the gastrointestinal tract of juvenile Burmese pythons (Python molurus)

摘要

The gastrointestinal tract of Burmese pythons (Python molurus (L., 1758)) exhibits large morphological and physiological changes in response to feeding and extended periods of fasting. In this study the mucosa of the stomach, small intestine, and colon were examined for changes in structure and cellular proliferation. The mucosa of fasting pythons exhibited low levels of cellular replication, but after feeding, cellular replication was evident as early as 12 h in the small intestine and colon and 24 h in the stomach. Replication peaked 3 days postfeeding for the small intestine and colon, but was still increasing at 6 days postfeeding in the stomach. Interestingly, cell proliferation was still evident after 45 days in the colon. In these tissues, a stock of "ready-to-use" primary lysosomes is found in the mucosal cells of fasting animals, whereas profound intracellular recycling is typical of animals that have been fed. These findings indicate that during the postprandial period, the intestinal mucosa undergoes extensive remodelling in anticipation of the next fasting and feeding period. One key adaptive factor for the python's ability to cope with infrequent feeding is a well-prepared digestive system in fasting animals that can quickly start functioning again when food becomes available.