Arashigis Research in Veterinary Science, in press. During the experiment, fish were observed for any clinical amazonicuus of diseases, including lack of appetite, increased opercular movements or visible lesions on the skin, tail and fins. Brycon amazonicus Zygote, vol. Development of feeding structures in larval fish with different life histories: Furthermore, leukocytes are the primary line of immunological defense, and in healthy B.
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Metrics details Abstract Hypoxia and mercury contamination often co-occur in tropical freshwater ecosystems, but the interactive effects of these two stressors on fish populations are poorly known.
Both species showed a bradycardia in progressive hypoxia. Hg exposure impaired cardiac electrical excitability, leading to first-degree atrioventricular block, plus profound extension of the ventricular action potential AP plateau. Moreover, there was the development of cardiac arrhythmias and anomalies such as occasional absence of QRS complexes, extra systoles, negative Q-, R- and S-waves QRS complex , and T wave inversion, especially in hypoxia below O2 partial pressures PO2 of 5.
Sub-chronic dietary Hg exposure induced intense bradycardia in normoxia in traira, plus lengthening of ventricular AP duration coupled with prolonged QRS intervals. This indicates slower ventricular AP conduction during ventricular depolarization. Overall, the data indicate that both acute waterborne and sub-chronic dietary exposure trophic level transfer , at sublethal concentrations of mercury, cause damage in electrical stability and rhythm of the heartbeat, leading to myocardial dysfunction, which is further intensified during hypoxia.
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Matrinxã (Brycon amazonicus)