Low water hardness and pH affect growth and survival of silver catfish juveniles

Abstract

The objective of this study was to investigate the effects of exposure to low water hardness (0, 25

Growth of silver catfish ( Rhamdia quelen ) exposed to acidic pH at different humic acid levels

“…In agreement with the abovementioned, the present study demonstrated that the development of silver catfish juveniles in water without HA was considerably lower at pH 5.5 than at pH 6.5 after 40 days. These results are also consistent with previous findings: silver catfish exposed to pH 5.5 showed lower growth compared to pH 7.0-7.5 (COPATTI et al, 2005;2011b); and no significant effect of pH was observed in the 6.0-8.0 range (COPATTI et al, 2011a).…”

“…These HA concentrations were chosen because they are within the range observed in the water of the Rio Negro Basin (KÜCHLER et al, 2000). The pH 5.5 decreases growth (COPATTI et al, 2011b) and pH 6.5 is within the optimum range (COPATTI et al, 2011a). Animals were fed daily to satiation at 9 am with the same commercial feed provided in the acclimation period.…”

“…Juveniles of silver catfish Rhamdia quelen maintained at pH 5.5 presented lower growth than those kept at pH 7.0-7.5 (COPATTI et al, 2005;2011b), probably due to a decrease in food consumption. The optimum pH range for growth of this species is 6.0-8.0 (COPATTI et al, 2011a). A study with green swordtail (Xiphophorus helleri) has been the only to report some beneficial effect on fish growth for humic substances (MEINELT et al, 2004).…”

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

“…Despite the protective effect of the high Ca 2+ level used in the present study against acidic water (COPATTI et al, 2011a(COPATTI et al, , 2011b and high ammonia (FERREIRA et al, 2013) on silver catfish growth, it was ineffective against the effect of high NO 2 -levels on growth and most biochemical parameters of this species. Hypoxia inhibited Ca 2+ uptake in zebrafish, Danio rerio (KWONG et al, 2016), and consequently the exposure of silver catfish to high Ca 2+ levels may facilitate the maintenance of plasma Ca 2+ levels and partially reduce the effect of tissue hypoxia (higher muscle lactate levels) provoked by high NO 2 -levels.…”

“…The increase of waterborne Ca 2+ can then reduce Cl -loss in freshwater fish and the activity of the Cl -/HCO 3 cotransporter, reducing NO 2 -uptake and toxicity. Studies have demonstrated that an increase of waterborne CaCl 2 has a stronger effect on reducing acute NO 2 -toxicity than an increase of waterborne NaCl in some species (TOMASSO et al, 1980;WEIRICH et al, 1993;KROUPOVA et al, 2005), but not in others (ATWOOD et al, 2001;KROUPOVA et al, 2005 (COPATTI et al, 2011a(COPATTI et al, , 2011b and high ammonia (FERREIRA et al, 2013) on silver catfish growth.…”