The effects of ammonia and water hardness on the hormonal, osmoregulatory and metabolic responses of the freshwater silver catfish Rhamdia quelen

Abstract

The aim of the present study was to assess the effects of ammonia and water hardness on endocrine, osmoregulatory and metabolic parameters in silver catfish (Rhamdia quelen). The specimens (60-120 g) were subjected to six treatments in triplicate, combining three levels of un-ionized ammonia (NH3)

Interação do cálcio e nitrito na água: sobrevivência, crescimento, parí­¢metros hematológicos e metabólicos em jundiá

“…The high Ca 2+ level alone was sufficient to reduce hepatic carbohydrate and protein levels of silver catfish in the present study. Previous work has shown that silver catfish exposed to 120 mg CaCO 3 L -1 (three-fold higher Ca 2+ level of the present study) for five days presented higher plasma glucose, lactate and triglyceride levels than those maintained at 25 mg CaCO 3 L -1 (BALDISSEROTTO et al, 2014) (similar conditions to the control group of the present study), suggesting that high Ca 2+ levels can induce some metabolic changes that apparently are not enough to alter growth.…”

Tolerance of piava juveniles to different ammonia concentrations

“…In the present study, the increase in lactate in the tissues suggests that the increase in NH 3 concentrations caused the piava to employ an anaerobic route with the use of lactate as substrate for gluconeogenesis. On the other hand, Baldisserotto et al (2014) did not show alterations in plasma lactate levels in silver catfish exposed to 0.18 or 0.50 mg L -1 NH 3 on the first 24 h of experiment.…”

“…The effects of NH 3 on plasma ion levels of freshwater fish seem to be highly species-dependent and vary according to the pH and NH 3 concentration of the water (BOLNER et al, 2014 Stressed fish are expected to increase plasma glucose and decrease glycogen levels to contribute to the increase in energy demand (BARCELLOS et al, 2004). However, piava exposed to high NH 3 concentrations (> 0.4 mg L -1) , had permanent stress, demonstrated by the higher mortality rates and lower glucose, glycogen and protein levels than control group and 0.1 mg L -1 NH 3 treatment after 96 h. Silver catfish exposed to 0.50 mg L -1 NH 3 increased significantly plasma glucose in the first 24 h, but presetned 100% mortality within 5 days (BALDISSEROTTO et al, 2014). So, the reduction in glucose and glycogen in the tissues can be explained by the use of these substrates in the energetic demand required for NH 3 excretion.…”

Rhamdia quelen (Quoy & Gaimard, 1824), submitted to a stressful condition: effect of dietary addition of the essential oil of Lippia alba on metabolism, osmoregulation and endocrinology

“…The mRNA expression was analyzed through qRT-PCR, using the StepOnePlus™ RT-PCR system (Applied Biosystems) with Power SYBR Green PCR Master Mix (Applied Biosystems). The sequences used to design all the primers were according to Baldisserotto et al (2014) using the Primer Express software 3.3 (Applied Biosystems). The results were normalized to the expression of the constitutive gene β-actin according to Baldisserotto et al (2014).…”

“…The sequences used to design all the primers were according to Baldisserotto et al (2014) using the Primer Express software 3.3 (Applied Biosystems). The results were normalized to the expression of the constitutive gene β-actin according to Baldisserotto et al (2014). The calculation of relative expression was performed as recommended by Pfaffl (2001).…”