Ghrelin and leptin modulate the feeding behaviour of the hawksbill turtle Eretmochelys imbricata during nesting season.
Female sea turtles have rarely been observed foraging during the nesting season. This suggests that prior to their migration to nesting beaches the females must store sufficient energy and nutrients at their foraging grounds and must be physiologically capable of undergoing months without feeding. Leptin (an appetite-suppressing protein) and ghrelin (a hunger-stimulating peptide) affect body weight by influencing energy intake in all vertebrates. We investigated the levels of these hormones and other physiological and nutritional parameters in nesting hawksbill sea turtles in Rio Grande do Norte State, Brazil, by collecting consecutive blood samples from 41 turtles during the 2010-2011 and 2011-2012 reproductive seasons. We found that levels of serum leptin decreased over the nesting season, which potentially relaxed suppression of food intake and stimulated females to begin foraging either during or after the post-nesting migration. Concurrently, we recorded an increasing trend in ghrelin, which may have stimulated food intake towards the end of the nesting season. Both findings are consistent with the prediction that post-nesting females will begin to forage, either during or immediately after their post-nesting migration. We observed no seasonal trend for other physiological parameters (values of packed cell volume and serum levels of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, γ-glutamyl transferase, low-density lipoprotein, and high-density lipoprotein). The observed downward trends in general serum biochemistry levels were probably due to the physiological challenge of vitellogenesis and nesting in addition to limited energy resources and probable fasting.
Departamento de Bioquímica, Laboratório de Bioquímica e Toxicologia, Universidade do Estado do Rio de Janeiro, Avenida 28 de Setembro 87, Rio de Janeiro, RJ 20551-030, Brazil; Fundação Pró-Tamar, Professor Ademir Francisco s/n, Barra da Lagoa, Florianópolis, SC 88061-160, Brazil.
Daphne Wrobel
DW
Goldberg
Departamento de Bioquímica, Laboratório de Bioquímica e Toxicologia, Universidade do Estado do Rio de Janeiro, Avenida 28 de Setembro 87, Rio de Janeiro, RJ 20551-030, Brazil.
Santiago Alonso Tobar
SA
Leitão
NC Wildlife Resources Commission, 1507 Ann Street, Beaufort, NC 28516, USA.
Matthew H
MH
Godfrey
Fundação Pró-Tamar, Caixa Postal 2219, Salvador, BA 40223-970, Brazil.
Gustave Gilles
GG
Lopez
Fundação Pró-Tamar, Caixa Postal 50, Fernando de Noronha, PE 53990-000, Brazil.
Armando José Barsante
AJ
Santos
Departamento de Fisiologia, Laboratório de Fisiologia da Nutrição e do Desenvolvimento, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ 20551-030, Brazil.
Fabiana Alves
FA
Neves
Departamento de Fisiologia, Laboratório de Fisiologia da Nutrição e do Desenvolvimento, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ 20551-030, Brazil.
Érica Patrícia Garcia
ÉP
de Souza
Departamento de Fisiologia, Laboratório de Fisiologia da Nutrição e do Desenvolvimento, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ 20551-030, Brazil.
Anibal Sanchez
AS
Moura
Departamento de Bioquímica, Laboratório de Bioquímica e Toxicologia, Universidade do Estado do Rio de Janeiro, Avenida 28 de Setembro 87, Rio de Janeiro, RJ 20551-030, Brazil.
Jayme da Cunha
Jda C
Bastos
Departamento de Bioquímica, Laboratório de Bioquímica e Toxicologia, Universidade do Estado do Rio de Janeiro, Avenida 28 de Setembro 87, Rio de Janeiro, RJ 20551-030, Brazil.
Vera Lúcia Freire da Cunha
VL
Bastos
Fasting; migration; peptide; protein; sea turtle