PICARD, Kathryn T.*; NEWSOM, Ellen; SECOR, Stephen M.; University of Alabama; University of Alabama; University of Alabama: Postprandial response of circulating metabolites for snakes

Snakes experience significant increases in metabolic rate after feeding stemming from the many activities employed to breakdown, absorb, and assimilate their large intact meals. In maintaining such high levels of metabolism for days, we hypothesized that snakes would require a continuous supply of fuel (glucose and lipids), and possibly experience a build up of lactate. Therefore, we investigated the postprandial response in plasma concentrations of triglycerides, glucose, and lactate for nine species of snakes. From fasted and fed snakes, drawn blood was centrifuged and samples of plasma assayed for each metabolite. The boids, Boa constrictor and Lichanura trivirgata, the pythonids, Python brongersmai, P. molurus, P. reticulatus, and P. sebae, and the colubrids Lampropeltis getula, Nerodia rhombifer, and Thamnophis sirtalis all experienced significant postfeeding increases in plasma triglycerides by orders of 8- to 118-fold. Colubrids on average possessed higher fasting concentrations of plasma triglycerides compared to boas and pythons. Postfeeding responses were more variable for plasma glucose and lactate. Only B. constrictor and N. rhombifer exhibited significant postprandial increases in plasma glucose (~ 150%). Plasma lactate levels increased by as much as 160% postprandially for the two boids, P. molurus, as well as for N. rhombifer. A postprandial increase in plasma lipids appears universal among snakes and may function in fueling digestion. Glucose, if released, may be metabolized very rapidly, and digestion can be taxing enough metabolically to generate lactate production.