Ultrasonographic Monitoring of Gallbladder Dynamics during Fasting and Feeding Conditions in Sheep

Abstract

Romaƒski K. W.: Ultrasonographic Monitoring of Gallbladder Dynamics during Fasting and Feeding Conditions in Sheep. Acta Vet. Brno 2004, 73: 29-35. The aim of this study was to evaluate the use of real-time ultrasonography for long-term studies of ovine gallbladder motor function and the assessment of the dynamics of gallbladder contractility in various fasting conditions and as the consequence of feeding with hay and grain mixture. Five adult sheep were selected in order to find the gallbladder shape suitable for the application of the ellipsoid method to estimate the gallbladder volume. In these animals, the ultrasonographic maximal-size gallbladder images were obtained every 10 min for periods of 3-5 h. Seven series of gallbladder length and height measurements were performed on each animal and the results were used to estimate the gallbladder volume utilizing the ellipsoid method. In animals fasted for 2 days, the gallbladder volume changed significantly (from 12.4 ± 1.2 to 24.2 ± 2.1 ml) in the fashion of cycles lasting usually longer than 100 min. In 1-day fasted animals, the fluctuations of gallbladder volume were less clear than in 2-day fasted animals and ranged from 16.3 ± 2.2 to 26.8 ± 4.3 ml. Feeding significantly lowered the gallbladder volume which gradually returned to values similar to those during the pre-feeding period. In non-fasted animals, feeding with hay evoked a longer contractile effect (control 30.6 ± 2.9 ml, feeding 14.2 ± 1.1 ml, p < 0.001) than feeding with a grain mixture (control 31.0 ± 3.3 ml, feeding 15.9 ± 3.2 ml, p < 0.05). Thus, the ultrasonographic method for gallbladder motility examination is useful in sheep and may provide important basic and clinical information. Furthermore, the results indicate that pre-duodenal mechanoreceptors and/or chemoreceptors can play a role in the control of gallbladder motility in sheep.