Lippia alba essential oil improves water quality during transport and accelerates the recovery of Potamotrygon wallacei from the transport-induced stress

Abstract

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.