Corticosterone Plasma levels of Embryos and Newly Hatched Broad-snouted Caiman (Caiman latirostris) Incubated at Different Temperatures

PARACHÚ MARCÓ, MARÍA VIRGINIA; PIÑA, CARLOS IGNACIO; SOMOZA, G.M.; GRACIELA ALMA JAHN; JOSEFINA LUCIANA IUNGMAN

Lake Charles

Congreso; 23th Reunión mundial del Grupo de Especialistas en Cocodrilos (CSG/SSC/UICN); 2014

CSG - McNeese State University

The temperature-sensitive period (TSP) is the time during development at which sex determination occurs in temperature-dependent sex determination systems, such as in caimans. It is also known the interplay among temperature and steroid hormones during TSP in temperature-dependent sex determination systems in crocodiles. This experiment was aimed to determine if incubation temperature affects plasma corticosterone levels in the Broad-snouted caiman (Caiman latirostris). Caiman eggs, taken from wild nests just after laying, were incubated at different temperatures (31, 33 and 34°C) until hatching. Plasmatic corticosterone was determined by radioimmunoassay (RIA) in embryos, after the TSP and in hatchlings. We obtained 100% of females at 31°C and 100% of males at 33 and 34°C incubation temperatures. Significant differences among nests were observed in plasma corticosterone. However, hormone levels showed no differences between sexes in Caiman latirostris embryos or after hatching. Corticosterone levels in embryos incubated at 31°C ranged from 0.01 to 2.2 ng/ml, in those incubated at 33°C range was 0.01 to 4.65 ng/ml, finally embryo incubated at the highest temperature ranged from 0.01 to 6.31 ng/ml. Hatchlings presented higher levels of corticosterone, those produced from incubation at 31°C ranged from 1.11 to 16.96, at 33°C from 2.85 to 11.5 and 34°C 2.72 to 13.77 ng/ml.