Ingesta passage and gastric emptying times in loggerhead sea turtles ( Caretta caretta)

Abstract

Ingesta passage times of soft flat foam dishes and gastric emptying time of barium-impregnated polyethylene spheres (BIPS ®) were measured in 22 and 8 loggerhead sea turtles ( Caretta caretta), respectively. Transit time ( T 1) was considered as the time between ingestion and first elimination, and retention time ( T 50) and total transit time ( T 85) the expulsion time of 50% and 85% of the markers, respectively. The experiments were carried out at different times of the year and water temperature was recorded. A set of dorso-ventral radiographs was taken to locate the BIPS ®, and the gastrointestinal anatomy of 5 dead turtles was studied to help with interpretation of the radiographs. No significant correlation was observed between T 1, T 50, T 85 and minimum straight carapace length (SCLmin) or body mass and no statistical difference was found in ingesta passage transit times between juvenile ( n = 6) and sub-adult turtles ( n = 16). Mean passage times of the dishes (in days) were: T 1 = 9.05, T 50 = 12.00 and T 85 = 13.19. Gastric emptying time using BIPS ® was 24–48 h. The transit time ( T 1) for the BIPS ® was longer (13.25 ± 4.86 days) than the foam markers (8.5 ± 2.73 days) in 8 turtles studied simultaneously. Although the total transit time tended to be faster in turtles submitted to water temperatures between 20 °C and 23.6 °C no significant correlation was observed between T 1, T 50 and T 85 and the temperature.