Thermal sensitivity of Bullfrog's immune response kept at different temperatures

Author(s)

Lima, Alan S. ; Ferreira, Leticia de F. ; Silva, Diego P. ; Gomes, Fernando R. ; Titon, Stefanny C. M.

• Document type: Journal article
• Source: OURNAL OF EXPERIMENTAL ZOOLOGY PART A-ECOLOGICAL AND INTEGRATIVE PHYSIOLOG; v. 333, n. 10, p. 12-pg., 2020-12-23.

Abstract

Climate change and emerging infectious diseases are often described as the main factors associated with the worldwide amphibian population decline. In this context, rising temperatures due to global warming might act as a chronic stressor for many amphibians, leading to immunosuppression. This study aimed to characterize the thermal sensitivity of the Bullfrog's (Lithobates catesbeianus) immune response and the effect of acclimation at different temperatures on it. Plasma bacterial killing ability (BKA) and phagocytosis activity of blood leukocytes were measured at different incubation temperatures (5-40 degrees C) in individuals kept at 28 degrees C and 34 degrees C. First, all individuals were held under 28 degrees C and sampled on the 16th day. Subsequently, one group was kept at 28 degrees, and the other one was transferred to 34 degrees C. Both groups were sampled at 83 and 106 days of maintenance. Plasma corticosterone (CORT) and testosterone (T) were assessed to evidence thermal stress and possible endocrine correlates of immune changes over time. The incubation temperature affected BKA both on animals kept at 28 degrees C and 34 degrees C, with maximum values at lower temperatures (5-20 degrees C). Phagocytosis activity was constant over the range of assay temperatures. Immune and endocrine variables decreased over time in both thermal regimes, but frogs maintained at 34 degrees C showed lower T and immunosuppression, evidencing stress response. Therefore, exposure to high temperatures might decrease immune function in bullfrogs due to chronic stress response and by exposition to temperatures of lower performance according to the thermal sensitivity curve, which might increase vulnerability to diseases in this anuran species. (AU)

• FAPESP's process: 19/07218-8 - Effect of acclimatization at different temperature on the thermal sensitivity of the bullfrog (Lithobates catesbeianus) immune response
• Grantee: Alan Siqueira Lima
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• FAPESP's process: 14/16320-7 - Impacts of climate/environmental change on the fauna: an integrative approach
• Grantee: Carlos Arturo Navas Iannini
• Support Opportunities: Research Program on Global Climate Change - Thematic Grants