Comparison between biochemical responses of the teleost pacu and its hybrid Tambacu (Piaractus mesopotamicus xColossoma macropomum) to short term nitrite exposure

Abstract

Aquatic environmental factors are very changeable in short periods. Among these factors are pH, temperature, dissolved oxygen, ammonia and ions. Nitrite, as one ion naturally present in aquatic systems, deserves particular consideration as it is highly toxic for many species. Among fish, nitrite may have harmful effects, such as methemoglobin (MtHb) formation, disruption to the gill and hepatic structure, which could result in hemolytic anemia and cell hypoxia by reducing the functional hemoglobin content. In this work, we compared hematological and metabolical responses of pacu and its hybrid tambacu exposed to 20 ppm of environmental nitrite. It was observed that the MtHb content was less than 18% in tambacu while pacu reached nearly 8%. These data reflect specific differences in nitrite uptake by the gill. The hematocrit of both fish was distinct; pacu did not have a typical response of poisoning by nitrite. This fact shows less skill of the hybrid to cope with environmental nitrite. Incipient hemolytic anemia was observed in pacu and both species presented a neoglycogenic profile. The glucose-provider character of the liver was more evident in tambacu. The white muscle of both species presented distinct metabolic behavior. While in pacu the white muscle was predominantly oxidative, in tambaqui the lactic fermentation was the most important metabolic profile. Metabolic and hematological observations in both species show that they present distinct metabolical strategies to cope with toxic effects of nitrite and there is no evidence that the hybrid is more resistant to nitrite.

Zootechnical Performance and Some Physiological Indices of Tambaqui, Colossoma macropomum Juveniles during Biofloc Maturation and in Different Feed Regimes

“…In addition, effects of peak N-NO2 − were detected in a reduction in hemoglobin. A similar response was described for tambacus (Piaractus mesopotamicus × Colossoma macropomum) submitted to toxic levels of N-NO2 − [66]. This response is due to the oxygen binding site of hemoglobin becoming occupied by N-NO2 − , transforming hemoglobin into methemoglobin and impairing oxygen transport [67].…”

<b>Water quality and survival rate of <i>Rhamdia quelen</i> fry subjected to simulated transportation at different stock densities and temperatures

“…Nitrite concentration in tropical fish farming systems at low stock density is usually low (0.03 -0.1 mg L -1 ) (Andrade et al, 2007). Some metabolic responses are similar to those observed after acute exposure to nitrite in other neotropical species (Moraes, Avilez, & Hori, 2006). However, it is not yet known whether this response is species-specific or dependent on exposure time (Lima, Alencar, Freitas, Packer, & Mourão, 2011).…”

Hematological Parameters of the Hybrid Serrasalmids Farmed in Central-Western Brazil

“…These parameters were also described for tambacus with parasites (Tavares-Dias et al, 2007Varandas et al, 2013) and subjected to capture stress in a "catch-and-release" fishing establishment (Varandas et al, 2013). Other studies reported the parameters of this species related to its red blood cells under the influence of exposure to nitrite (Moraes et al, 2006). The biochemical parameters of its blood, including quantification of total serum protein (Tavares-Dias and Moraes, 2010), were also previously assessed, along with the characterization of the acute inflammatory response in this species based on the counts of defensive (i.e.…”