Ammonia‐, Sodium Chloride‐, and Calcium Sulfate‐induced Changes in the Stress Responses of Jundiá, Rhamdia quelen,Juveniles |
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| Authors: | Paulo César Falanghe Carneiro Elaine Correa Swarofsky Daniana Pinotti E Souza Thiago Mocelin Ramos César Bárbara Baglioli Bernardo Baldisserotto |
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| Institution: | 1. Embrapa Tabuleiros Costeiros, Av. Beira Mar, 3250, 49025‐040 Aracaju, SE, Brazil;2. LAPEP‐PUCPR, Rua Benjamim Claudino Barbosa, 13600, 83005‐970. S?o José dos Pinhais, PR, Brazil;3. Departamento de Fisiologia e Farmacologia, Universidade Federal de Santa Maria, 97105‐900, Santa Maria, RS, Brazil |
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| Abstract: | Salt (NaCl) and gypsum (CaSO4) are used as water additives to mitigate fish stress and improve specimen survival. High stocking densities and the transportation of fish can increase aqueous ammonia, which can, in turn, alter fish cortisol secretion. The objectives of this study were to assess the effects of salt, gypsum, and aqueous ammonia on some stress‐induced physiological responses of jundiá, Rhamdia quelen, juveniles induced by captivity and handling, and to determine the lethal ammonia concentration for this species. Jundiá juveniles were subjected to the following five treatments: water only, water + ammonia (0.4 mg/L), water + NH3 + NaCl (6 g/L), water + NH3 + gypsum (150 mg/L), and water + NH3 + NaCl + gypsum. Blood samples were taken after intervals of 1, 5, 24, and 96 h, and the concentrations of cortisol, glucose, chloride, ammonia, and hematocrit were determined. The NH3 LC50 value after 96 h of exposure (LC50?96h) was measured to be 1.9 mg/L NH3. Either salt or gypsum reduced both cortisol and glucose levels during most of the experimental period, but the combination of both reduced these levels even further. The combined use of NaCl and CaSO4 demonstrates a synergic effect on mitigating stress responses induced by handling and aqueous ammonia in jundiá juveniles. |
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