Hormonal and metabolic responses of juvenile alligators to cold shock

Lance, Valentine A.; Elsey, Ruth M.

doi:10.1002/(sici)1097-010x(19990501)283:6<566::aid-jez8>3.0.co;2-9

Cited by 34 publications

(8 citation statements)

References 25 publications

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“…While the spectacled caiman was largely indifferent to the stressors (handling, flash), the black caiman was affected by both. In this species, handling and photographic flashes hyperstimulated the HPA axis, as has also been shown for American alligators (Lance and Elsey 1999 a,b ). The CORT concentration of black caiman in the flash treatment was 1.6 times higher than in the handling treatment, and 2.7 times higher than the control group.…”

Section: Discussionsupporting

confidence: 73%

Conservation implications of tourism and stress for Amazonian caimans

Mendonça,

Duncan,

Vidal

et al. 2023

J Wildl Manag

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Ecotourism is a strategy for biodiversity conservation, but it involves possible negative effects on animal health and welfare. Large predators such as crocodilians are one of the great public attractions sought after for tourist interactions. Interactions with wild animals and humans can hyperstimulate the hypothalamic‐pituitary‐adrenal axis in the short term, in the case of crocodilians showing an increased corticosterone level, which is indicative of physiological stress. Between September and December 2019, we simulated interactions between tourists and Amazonian crocodilians at Anavilhanas National Park in Central Amazonia, Brazil to evaluate the effects of handling and use of photographic flashes on black caiman (Melanosuchus niger) and spectacled caiman (Caiman crocodilus) on circulating corticosterone and lactate. Corticosterone levels increased 1.7‐fold during handling and 2.7‐fold when exposed to photographic flashes in black caiman but not in spectacled caiman. Increased corticosterone concentrations in black caiman were characterized by an increase caused by handling and were more intense after flashes than in controls, but the combination of handling and flash had no effect. During handling in simulated tourist interactions, anaerobic respiration increased lactate in black caiman but not in spectacled caiman. The effect of simulated tourist interactions with Amazonian crocodilians was dependent on the handling and especially on flash use in black caiman. The results can assist management, conservation programs, and public policies, especially in programs based on tourism interaction with Amazonian crocodilians.

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Section: Discussionsupporting

confidence: 73%

Conservation implications of tourism and stress for Amazonian caimans

Mendonça,

Duncan,

Vidal

et al. 2023

J Wildl Manag

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“…For example, in juvenile alligators subjected to a brief cold shock lasting 20 min, corticosterone concentrations and the percent lymphocytes were elevated at 1 hr, but by 24 hr poststressor both had returned to baseline levels. In contrast, the percent heterophils was unchanged at 1 hr but elevated at 24 hr (Lance and Elsey, Lance and Elsey, ). Similarly, subjecting juvenile alligators to a prolonged restraint stress (e.g., 48 hr) resulted in both elevated corticosterone and H:L ratio, but the patterns of the increase differed substantially.…”

Section: Discussionmentioning

confidence: 99%

Influence of Stressor Duration on Leukocyte and Hormonal Responses in Male Southeastern Five‐Lined Skinks (Plestiodon inexpectatus)

Seddon

2012

J. Exp. Zool.

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Environmental stressors elicit elevations of plasma glucocorticoid hormones. Stressors also result in increases in the circulating heterophil to lymphocyte ratio (H:L ratio), which has been linked to increased glucocorticoids. Recently, there has been debate about the extent to which stress-induced elevations of corticosterone are tied to increases in the H:L ratio and about whether one measure of physiological stress might be used in lieu of the other. Few studies have examined the responses of both variables to standardized stressors in free-living animals, especially reptiles. Stressors may also affect levels of other hormones, such as prostaglandins or testosterone, that may influence leukocytes. Therefore, the H:L ratio, corticosterone, prostaglandin E(2) (PGE(2) ), and testosterone were monitored in free-living male southeastern five-lined skinks, Plestiodon inexpectatus, in response to various durations of confinement stress. Skinks confined for 1 hr had elevated H:L ratios and elevated corticosterone concentrations. In addition, corticosterone was positively correlated with the H:L ratio. In contrast, there were no effects of 2 hr of confinement on the H:L ratio, in spite of maximal corticosterone. Plasma PGE(2) was not affected by 15, 30, or 60 min of confinement but was positively correlated with monocytes and negatively correlated with lymphocytes in the 1 hr of confinement experiment. Consistent with many other studies of reptiles, confinement stress did not result in suppressed testosterone. Overall, the results indicate that, in reptiles at least, the H:L ratio and plasma corticosterone do not covary consistently and one measure of stress cannot be used in lieu of the other.

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“…As already discussed, imunosuppression and increased susceptibility to infectious agents could have been the result of stress related to captive conditions. Indeed, in juvenile American alligators, stress has been shown to alter plasma corticosterone concentrations and white blood-cell parameters (Lance and Elsey, 1999). In the present study, immunosuppression could also have been related to exposure to OCPs.…”

Section: Relationship Between Ocps and Abnormalitiesmentioning

confidence: 49%

Necropsy Findings in American Alligator Late-Stage Embryos and Hatchlings From Northcentral Florida Lakes Contaminated With Organochlorine Pesticides

Sepúlveda

Piero

Wiebe³

et al. 2006

Journal of Wildlife Diseases

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ABSTRACT:Increased American alligator (Alligator mississippiensis) embryo and neonatal mortality has been reported from several northcentral Florida lakes contaminated with old-use organochlorine pesticides (OCPs). However, a clear relationship among these contaminants and egg viability has not been established, suggesting the involvement of additional factors in these mortalities. Thus, the main objective of this study was to determine the ultimate cause of mortality of American alligator late-stage embryos and hatchlings through the conduction of detailed pathological examinations, and to evaluate better the role of OCPs in these mortalities. Between 2000 and 2001, 236 dead alligators were necropsied at or near hatching (after ,65 days of artificial incubation and up to 1 mo of age posthatch). Dead animals were collected from 18 clutches ranging in viability from 0% to 95%. Total OCP concentrations in yolk ranged from ,100 to 52,000 mg/kg, wet weight. The most common gross findings were generalized edema (34%) and organ hyperemia (29%), followed by severe emaciation (14%) and gross deformities (3%). Histopathologic examination revealed lesions in 35% of the animals, with over half of the cases being pneumonia, pulmonary edema, and atelectasis. Within and across clutches, dead embryos and hatchlings compared with their live cohorts were significantly smaller and lighter. Although alterations in growth and development were not related to yolk OCPs, there was an increase in prevalence of histologic lesions in clutches with high OCPs. Overall, these results indicate that general growth retardation and respiratory abnormalities were a major contributing factor in observed mortalities and that contaminants may increase the susceptibility of animals to developing certain pathologic conditions.

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Hormonal and metabolic responses of juvenile alligators to cold shock

Cited by 34 publications

References 25 publications

Conservation implications of tourism and stress for Amazonian caimans

Conservation implications of tourism and stress for Amazonian caimans

Influence of Stressor Duration on Leukocyte and Hormonal Responses in Male Southeastern Five‐Lined Skinks (Plestiodon inexpectatus)

Necropsy Findings in American Alligator Late-Stage Embryos and Hatchlings From Northcentral Florida Lakes Contaminated With Organochlorine Pesticides

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