Corticosterone–immune interactions during captive stress in invading Australian cane toads (Rhinella marina)

Dehydration as a stressor in toads (Rhinella ornata)

“…Toads experimentally submitted to dehydration corresponding to 10% of standard body mass and to restraint showed 6.7 ‐ and 7‐fold higher CORT, respectively, than hydrated and nonrestrained toads. The CORT values observed in R. ornata evidence a stress response to moderate dehydration comparable to those observed in previous studies using the same protocol of restraint, a protocol commonly used to promote acute stress response in Rhinella species, including R. ornata (Assis et al, , in press; Gomes et al, ; Graham, Kelehear, Brown, & Shine, ). Moreover, dehydration by 20% resulted in 23‐fold increase in CORT when compared hydrated and nonrestraint toads, evidencing that an intense dehydration in R. ornata can lead to a more intense stress response.…”

Dehydration as a stressor in toads (Rhinella ornata)

“…Toads experimentally submitted to dehydration corresponding to 10% of standard body mass and to restraint showed 6.7 ‐ and 7‐fold higher CORT, respectively, than hydrated and nonrestrained toads. The CORT values observed in R. ornata evidence a stress response to moderate dehydration comparable to those observed in previous studies using the same protocol of restraint, a protocol commonly used to promote acute stress response in Rhinella species, including R. ornata (Assis et al, , in press; Gomes et al, ; Graham, Kelehear, Brown, & Shine, ). Moreover, dehydration by 20% resulted in 23‐fold increase in CORT when compared hydrated and nonrestraint toads, evidencing that an intense dehydration in R. ornata can lead to a more intense stress response.…”

Innate immunity and testosterone rapidly respond to acute stress, but is corticosterone at the helm?

“…We found that innate immune capacity, as measured by plasma agglutination and lysis, rapidly decreases during acute stress. This finding is generally consistent with the results of previous studies in mammals, birds, nonavian reptiles, and amphibians (French et al 2010;Gelling et al 2009;Graham et al 2012;Matson et al 2006;Merrill et al 2012;Millet et al 2007). The specific immunological mechanism(s) underlying this decrease in innate immune performance and its significance are unclear.…”

“…Our study investigated whether the decline in innate immunity during stress is correlated with concomitant changes in plasma CORT and/or T. Previous studies have found that stress-induced plasma CORT was negatively correlated with bactericidal capacity (Millet et al 2007) and a greater stress-induced increase in plasma CORT was associated with a more robust phagocytic response (Graham et al 2012). In contrast to these studies, we found no correlation between innate immune performance and either initial or stress-induced plasma CORT.…”

Effects of Acute Restraint Stress, Prolonged Captivity Stress and Transdermal Corticosterone Application on Immunocompetence and Plasma Levels of Corticosterone on the Cururu Toad (Rhinella icterica)

“…As previously observed for other tetrapods, including anurans kept under captivity for hours to days [ 21 – 23 , 45 – 50 ], captivity maintenance for 24h increased CORT in R . icterica when compared to values found for free individuals in the field.…”

Dehydration as a stressor in toads (Rhinella ornata)

“…Toads experimentally submitted to dehydration corresponding to 10% of standard body mass and to restraint showed 6.7 ‐ and 7‐fold higher CORT, respectively, than hydrated and nonrestrained toads. The CORT values observed in R. ornata evidence a stress response to moderate dehydration comparable to those observed in previous studies using the same protocol of restraint, a protocol commonly used to promote acute stress response in Rhinella species, including R. ornata (Assis et al, , in press; Gomes et al, ; Graham, Kelehear, Brown, & Shine, ). Moreover, dehydration by 20% resulted in 23‐fold increase in CORT when compared hydrated and nonrestraint toads, evidencing that an intense dehydration in R. ornata can lead to a more intense stress response.…”

Innate immunity and testosterone rapidly respond to acute stress, but is corticosterone at the helm?

“…We found that innate immune capacity, as measured by plasma agglutination and lysis, rapidly decreases during acute stress. This finding is generally consistent with the results of previous studies in mammals, birds, nonavian reptiles, and amphibians (French et al 2010;Gelling et al 2009;Graham et al 2012;Matson et al 2006;Merrill et al 2012;Millet et al 2007). The specific immunological mechanism(s) underlying this decrease in innate immune performance and its significance are unclear.…”

“…Our study investigated whether the decline in innate immunity during stress is correlated with concomitant changes in plasma CORT and/or T. Previous studies have found that stress-induced plasma CORT was negatively correlated with bactericidal capacity (Millet et al 2007) and a greater stress-induced increase in plasma CORT was associated with a more robust phagocytic response (Graham et al 2012). In contrast to these studies, we found no correlation between innate immune performance and either initial or stress-induced plasma CORT.…”

Effects of Acute Restraint Stress, Prolonged Captivity Stress and Transdermal Corticosterone Application on Immunocompetence and Plasma Levels of Corticosterone on the Cururu Toad (Rhinella icterica)

“…As previously observed for other tetrapods, including anurans kept under captivity for hours to days [ 21 – 23 , 45 – 50 ], captivity maintenance for 24h increased CORT in R . icterica when compared to values found for free individuals in the field.…”

Dehydration as a stressor in toads (Rhinella ornata)

“…Toads experimentally submitted to dehydration corresponding to 10% of standard body mass and to restraint showed 6.7 ‐ and 7‐fold higher CORT, respectively, than hydrated and nonrestrained toads. The CORT values observed in R. ornata evidence a stress response to moderate dehydration comparable to those observed in previous studies using the same protocol of restraint, a protocol commonly used to promote acute stress response in Rhinella species, including R. ornata (Assis et al, , in press; Gomes et al, ; Graham, Kelehear, Brown, & Shine, ). Moreover, dehydration by 20% resulted in 23‐fold increase in CORT when compared hydrated and nonrestraint toads, evidencing that an intense dehydration in R. ornata can lead to a more intense stress response.…”

Innate immunity and testosterone rapidly respond to acute stress, but is corticosterone at the helm?

“…We found that innate immune capacity, as measured by plasma agglutination and lysis, rapidly decreases during acute stress. This finding is generally consistent with the results of previous studies in mammals, birds, nonavian reptiles, and amphibians (French et al 2010;Gelling et al 2009;Graham et al 2012;Matson et al 2006;Merrill et al 2012;Millet et al 2007). The specific immunological mechanism(s) underlying this decrease in innate immune performance and its significance are unclear.…”

“…Our study investigated whether the decline in innate immunity during stress is correlated with concomitant changes in plasma CORT and/or T. Previous studies have found that stress-induced plasma CORT was negatively correlated with bactericidal capacity (Millet et al 2007) and a greater stress-induced increase in plasma CORT was associated with a more robust phagocytic response (Graham et al 2012). In contrast to these studies, we found no correlation between innate immune performance and either initial or stress-induced plasma CORT.…”

Effects of Acute Restraint Stress, Prolonged Captivity Stress and Transdermal Corticosterone Application on Immunocompetence and Plasma Levels of Corticosterone on the Cururu Toad (Rhinella icterica)

“…As previously observed for other tetrapods, including anurans kept under captivity for hours to days [ 21 – 23 , 45 – 50 ], captivity maintenance for 24h increased CORT in R . icterica when compared to values found for free individuals in the field.…”