Like any surgical procedure, a gastrojejunostomy could result in infection or another complication. A gastrojejunostomy connects the stomach to the jejunum, bypassing the duodenum, the beginning of the intestine at the bottom of this image.
One more thing: Don't make your turtle's water temperature too warm. For most adult aquatic turtle species, 78 F. (25.5 C.) is the highest you want unless you're treating them for an illness and a veterinarian has told you to raise the temperature. Otherwise, too-warm water can encourage bacteria growth in the tank. It also discourages turtles from basking sometimes.
Green sea turtles can stay under water for as long as five hours even though the length of a feeding dive is usually five minutes or less. Their heart rate slows to conserve oxygen: nine minutes may elapse between heartbeats.