OTT, BD*; SECOR, SM; Univ. of Alabama; Univ. of Alabama: Postprandial Upregulation of Intestinal Morphology and Function in Python

Infrequently feeding snakes such as boas, pythons, and rattlesnakes have demonstrated that their digestive tract severely downregulates during periods of fasting and rapidly upregulates after the ingestion of a meal. While fasting, small intestinal mass decreases and nutrient transport rates decline as an energy saving mechanism for these snakes. In order to reveal any evolutionary trends associated with these physiological traits in the genus Python, we examined postprandial changes in nutrient transport, intestinal mass, and enterocyte size of the blood python (P. brongersmai), ball python (P. regius), reticulated python (P. reticulatus), northern African python (P. sebae), and Burmese python fed rat meals equaling 25% of their body mass. In response to the 25% size meal, transport rates of the amino acids L-leucine and L-proline increased on average 1-, 5-, 3-, 5-, and 3-fold for P. brongersmai, P. molurus, P. regius, P. reticulatus, and P. sebae, respectively. D-Glucose transport rates experienced 27-, 8-, 23-, 14-, and 16-fold increases, respectively. On average, small intestinal mass of all five species increased by 100% above the fasted mass. Nutrient uptake capacity, a product of uptake rate and intestinal mass, increased on average 8-fold for L-leucine, 6-fold for L-proline, and 33-fold for D-glucose for all five species. Enterocyte volume of the small intestine increased with feeding by 30%, 50%, and 50% for P. molurus, P. reticulatus, and P. sebae, respectively, concurrently with a 5-fold increase in microvillus length. With a similar response of the small intestine to fasting and feeding, it appears that these five species utilize the ability to widely regulate intestinal performance to cope with extended periods of fasting.