Effects of Ultimobranchialectomy on the Mineral Balances of the Plasma and Bile in the Stingray (Elasmobranchii)

Abstract

Effects of ultimobranchialectomy (UBX) on plasma and bile minerals were examined in the stingray Dasyatis akajei (Elasmobranchii). Plasma urea and glucose concentrations were also measured as references. At 1 week after the operation, plasma CT level in the UBX group was significantly lower than that in the sham-operated (SHAM) group. However, there was no significant difference in plasma Ca level between UBX and SHAM groups at 1 week. On the other hand, bile Ca concentration in the UBX group was significantly lower than that in the SHAM group. Bile K and Cl levels, and bile volumes in the UBX group were significantly higher than those in the SHAM group. These results suggests that in the stingray, CT may function to control bile mineral concentrations.