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The current work investigated whether the long transport could impact the water quality, the response to stress, the antioxidant defense system in cururu stingray (Potamotrygon wallacei) liver, and how a recovery process could affect them. Furthermore, it also examined the effects of the Lippia alba essential oil (EOLA) on these transport-induced changes. For this purpose, the cururu stingray (n = 30) were transported in plastic bags (from 3 to 4 specimens, each bag) in the absence or presence of EOLA at 10 μL/L from Manaus (Amazonas, Brazil) to Santa Maria (Rio Grande do Sul, Brazil) for about 32 h. A set of cururu stingray was sampled immediately at the arrival (n = 5 for each condition, without or with EOLA). The remaining individuals were kept for 24 h (n = 5 for each condition, without or with EOLA) and 48 h (n = 5 for each condition, without or with EOLA) to assess their recovery from the trip. After it, they were anesthetized for blood collection, and then, euthanized for liver removal. A set of cururu stingray was sampled before starting the transport protocol (n = 5). Water samples were collected during all steps for monitoring its quality. First of all, when the transport was carried out in the absence of EOLA, it resulted in higher ammonia levels in water linked to a hyperglycemic response, and an impairment in the glutathione-related antioxidant system characterized by decreased total glutathione, and catalytic subunit of glutamate cysteine ligase levels as well as glutathione S-transferase, and glucose-6-phosphate-dehydrogenase activities, thus leading the cururu stingray liver to lipid peroxidation at its arrival. The EOLA, in turn, avoided most transport-induced changes at the arrival. Furthermore, it also helped the antioxidant system to retrieve its optimal function in the liver after 48 h recovery, speeding up the recovery process that could take more than 48 h when transport was completed in the absence of this additive. Therefore, the addition of EOLA to the transport water at 10 μL/L is highly advisable when transporting cururu stingray for more than 30 h. [Display omitted] • Cururu stingray transport increases ammonia levels in water. • Transport triggers an hyperglycemic response, an stress index. • The glutathione-related antioxidant system in the liver is affected by transport. • Lippia alba essential oil improves water quality during transport. • Lippia alba accelerates the recovery from the transported-induced stress. [ABSTRACT FROM AUTHOR]

When captured, free‐living crocodilians respond by hyperstimulation of the hypothalamic‐pituitary‐adrenal (HPA) axis, which triggers a cascade of downstream events of physiological stress. We examined these responses in two unstressed, and stressed Amazonian caimans, Caiman crocodilus and Melanosuchus niger. Plasma corticosterone levels increased in both stressed caiman species. In M. niger, the levels of this hormone increased 5.2‐fold compared with the basal range values, while in C. crocodilus this was only 1.7‐fold. After stress, M. niger needed more than 6 h to return its corticosterone levels to basal range values, whereas in C. crocodilus just 0.5 h was enough. Downstream events were characterized by an increase in glucose levels, which is associated with corticosterone increments. Excessive muscle activity resulted in increased plasma lactate content in both species. Lactate levels were also related to plasma calcium concentration, possibly due to the buffering capacity for preventing lactic acidosis. Clearance of excessive lactate load was faster in M. niger (0.5 h) than in C. crocodilus (more than 6 h). Although both caiman species respond in the same way to capture, the amplitude and duration of activation of the HPA axis are different. M. niger may be potentially more sensitive to acute stress than C. crocodilus. On the other hand, C. crocodilus needs more time to recover from the lactic acid load. Our experiment provides a useful diagnostic tool for management and conservation programs, as well as evaluating the impacts of tourism and recreational capture on caimans in the Amazon. Highlights: In both stressed species, capture stress resulted in increased plasma corticosterone, glucose, lactate, and calcium levels.The physiological responses observed in Melanosuchus niger indicate that it is more susceptible to acute stress conditions. [ABSTRACT FROM AUTHOR]

This study aimed to determine whether the long-term transport model of cururu stingray (Potamotrygon wallacei) could disturb the brain redox status and brain functions, including antioxidant defenses, signaling pathways activated by oxidative stress, and the physiological responses to transport-induced stress upon arrival and after its recovery; and also to identify how the addition of essential oil of Lippia alba (EOLA) in the water transport could influence on these changes. For this reason, the cururu stingrays were anesthetized with 200 mg/L eugenol and sampled by sectioning of the spinal cord before transport (n = 5), after 32 h-transport in the absence (n = 5) and presence of 10 μL/L of the EOLA (n = 5); and after recovery for 24 h and 48 h post-transport without and with EOLA (n = 5, each group) for blood and brain removal, totalizing 35 animals (four replicates). Transport triggered a rise in the levels of lactate in plasma and brain of cururu stingray on arrival. Besides, it increased the superoxide anion (O 2 •-) and hydrogen peroxide (H 2 O 2) levels, and decreased the superoxide dismutase (SOD) 1 and 2, catalase, glutathione peroxidase (GPx) 1, and glutathione reductase (GR) activities, activated nuclear factor κB (NF-κB), led to glutathione oxidation, lipid peroxidation (measured through the thiobarbituric acid reactive substances (TBARS)), and elevated heat shock protein 70 (HSP70) levels in the cururu stingray brain. The addition of the EOLA to water protected brain against stress and oxidative stress on arrival, speeding up a process that could take until 48 h to occur in the absence of this additive. To reach this response, the EOLA decreased lactate levels in plasma and brain of cururu stingray, and also reduced O 2 •- and H 2 O 2 levels, and NF-κB activation, increased SOD2, catalase, GPx1 and GR activities, decreased the ratio between oxidized and reduced glutathione, avoiding the increase in the TBARS levels in the brain tissue, and regulated the physiological responses to stress, as illustrated by low HSP70 levels found in it. These data make the addition of EOLA to the water even more recommended for long-term transport of cururu stingrays. • Cururu stingray transport increases lactate in plasma and brain. • Transport triggers reactive oxygen species formation in brain. • The antioxidant defenses are deficient in the brain after transport. • Lippia alba essential oil decreases transport-induced oxidative stress. • Lippia alba regulates the physiological responses to stress. [ABSTRACT FROM AUTHOR]

This paper aimed to study and compare the hematology of newborns, young, subadults, adult males, adult females and pregnant females of Potamotrygon wallacei (cururu stingray), Potamotrygon motoro and Paratrygon aiereba . Newborn cururu stingrays had lower red blood parameters than those of other development stages. Thrombograms and leukograms showed a conservative pattern between development stage, sexual dimorphism and pregnancy. In P. motoro and P. aiereba , variables relating to red blood parameters, biochemistry and leukograms showed little variation between the species' biological characteristics, thus showing that these variables are not good criteria for differentiating them within the same species. In conclusion, the development stage is an important factor for differentiating hematological properties in the cururu stingray, while this has not been observed in P. motoro and P. aiereba stingrays. [ABSTRACT FROM AUTHOR]