Óleo essencial de Lippia alba no transporte de arraias cururu (Potamotryogon wallacei): efeitos em biomarcadores teciduais

Abstract

The ornamental fish trade generates income for the riverside population of the state of Amazonas in Brazil. Amazonian species are in greater demand because they are often endemic, which values them. The cururu stingray (Potamotryogon wallacei) is a widely sought after species for aquarium hobby, with export as the main market. This work investigated the impact of transport for long hours on water quality, stress response, antioxidant defense system of the can cururu stingray liver and how the recovery process would occur. The effects of Lippia alba essential oil (EOLA) were also studied against the changes imposed by transport. The stingrays cururu (n = 30) were transported in plastic bags (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 group of cururu stingrays was sampled immediately on arrival (n = 5 for each condition, with or without 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 the recovery from the trip. Afterwards, they were anesthetized for blood collection and then euthanized to remove the liver. A group of cururu stingrays was sampled before starting the transport protocol (n = 5). Water samples were collected during all stages to monitor their quality. First, when transport was performed in the absence of EOLA, it resulted in higher levels of ammonia in the water linked to a hyperglycemic response and an impairment in the glutathione-related antioxidant system characterized by decreased total glutathione and catalytic subunit of cysteine glutamate levels. ligase, as well as glutathione S-transferase and glucose-6-phosphate dehydrogenase activities, leading the cururu stingray liver to lipid peroxidation upon arrival. EOLA, in turn, avoided most transport-induced changes on arrival. Furthermore, it also helped the antioxidant system to regain its optimal liver function after 48 h of 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 stingrays for more than 30 h.