Meeting Abstract
Amphibian populations are declining worldwide. Thermal regimes alterations and emerging infectious diseases are often described as the most important factors associated with this pattern. Temperature change alters both pathogen physiology and host immune response performance against infection. The aim of this study was to characterize the thermal sensitivity of the Bullfrog’s (Lithobates catesbeianus) immune response and the effect of acclimation at different temperatures (28°C and 34°C) on it. Male bullfrogs (n = 12) were kept on a climatic chamber at 28°C for seven days, then a blood sample was collected. After 30 days at 28°C, the animals were divided in two groups: maintenance at 28°C (n = 6) or 34°C (n = 6). New blood samples were taken 20 and 40 days after the group’s settlement. Phagocytosis assays were conducted with the blood leukocytes, and bacterial killing ability (BKA) assays with the plasma. The assays were conducted at different incubation temperatures (5-40°C, 5°C range intervals). The incubation temperature affected BKA either on animals kept at 28°C and 34°C, with maximum values at lower temperatures (5-20°C), but did not affect the cellular response (phagocytosis). Although phagocytosis and BKA decreased over time for both animals kept at 28°C and 34°C, there was no shift on thermal sensitivity curves in function of maintenance temperature. Moreover, immune parameters were generally characterized by sustained high values in large range of incubation temperature, indicating an eurythermal feature of the Bullfrog´s immune response.
