Dehydration as a stressor in toads (Rhinella ornata)

Autor(es)

Giorgi Barsotti, Adriana Maria ; Titon Junior, Braz ; Monteiro Titon, Stefanny Christie ; Gomes, Fernando Ribeiro

• Tipo de documento: Artigo Científico
• Fonte: OURNAL OF EXPERIMENTAL ZOOLOGY PART A-ECOLOGICAL AND INTEGRATIVE PHYSIOLOG; v. 331, n. 3, p. 7-pg., 2019-03-01.

Resumo

Availability of a humid environment is essential for amphibians to carry out their activities and most species are characterized by low resistance to evaporative water loss. Moreover, dehydration severely compromises amphibian locomotor and foraging performance, representing a relevant selective factor modulating the evolution of its integrative phenotype. In this way, we hypothesized that dehydration is a stressor for toads, inducing a stress response comparable to that elicited by another commonly used stress protocol: restraint challenge. We evaluated changes in plasma levels of corticosterone (CORT), hematocrit (Hct), and neutrophil:lymphocyte (N:L) ratio in adult males of Rhinella ornata, experimentally submitted to different levels of hydration (100%, 90%, and 80% of standard body mass) and to restraint challenge. Our results showed that dehydrating toads by 10% increase CORT to levels equivalent to that obtained by restraint. Moreover, toads dehydrated by 20% show a more pronounced increase in CORT, along with increased Hct and N:L ratio. In this way, we corroborated the hypothesis that dehydration triggers a pronounced stress response in R. ornata. Highlights Dehydration can elicit a stress response in toads, by increasing corticosterone plasma levels and neutrophil:lymphocyte ratio. Corticosterone plasma levels were higher in individuals 20% dehydrated than in subjects submitted to restriction of movement, showing that dehydration may offer high intensity stress. (AU)

• Processo FAPESP: 13/00900-1 - Estudo comparativo das relações entre imunocompetência e níveis plasmáticos de esteróides inter-renais e gonadais em sapos
• Beneficiário: Fernando Ribeiro Gomes
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 14/16320-7 - Impactos das mudanças climáticas e ambientais sobre a fauna: uma abordagem integrativa
• Beneficiário: Carlos Arturo Navas Iannini
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Temático
• Processo FAPESP: 16/05024-3 - Estresse hídrico e resposta imune em sapos (Rhinella ornata) habitando fragmentos de Floresta Atlântica
• Beneficiário: Adriana Maria Giorgi Barsotti
• Modalidade de apoio: Bolsas no Brasil - Doutorado