Ethical research as the target of animal extremism: an international problem

Animal extremism has been increasing worldwide; frequently researchers are the targets of actions by groups with extreme animal rights agendas. Sometimes this targeting is violent and may involve assaults on family members or destruction of property. In this article, we summarize recent events and suggest steps that researchers can take to educate the public on the value of animal research both for people and animals

Changes in gut gross morphology of traíra, Hoplias malabaricus (Teleostei, Erythrinidae) during long-term starvation and after refeeding

Traíras (Hoplias malabaricus) adultas foram submetidas a diferentes períodos de privação de alimento (de 30 a 240 dias) e realimentadas por 30 dias após 90 e 240 dias de jejum. O comprimento do estômago permaneceu constante durante todo o tempo experimental. No entanto, o comprimento do intestino reduziu significativamente após 30 dias de jejum. O comprimento normal não foi recuperado após a realimentação. O número de cecos pilóricos não sofreu modificações significativas. Por outro lado, a espessura dos cecos diminuiu após 150 dias de privação de alimento e seu comprimento diminuiu após 180 dias. Após a realimentação, porém, os cecos pilóricos recuperaram a espessura original. Nos peixes realimentados após 240 dias de jejum, os comprimentos dessas estruturas aparentemente apresentaram crescimento compensatório, tornando-se mais longas que as do grupo controle.

The effect of hypoxia and recuperation on carbohydrate metabolism in pacu (Piaractus mesotamicus)

A study of the hematological parameters, glycogen, glucose, and lactate, and the activity of malate and lactate dehydrogenases was carried out in blood and tissues of fishes submitted to two, four, and six hours of hypoxia and recuperation. Only after 4 h of hypoxia was there a drop in liver glucose. After 6 h, a drop in lactate and a rise in glucose in practically all tissues signaled a recuperation of the metabolism, probably due to ASR (aerial surface respiration). Lactate formed during hypoxia was canalized to heart and brain for oxidation and used for neoglucogenesis. There were no changes in hematological parameters nore in the activity of malate and lactate dehydrogenases during normoxia and hypoxia, which suggest that these adaptive mechanisms may not be involved during hypoxia. Glycogen concentrations did not show variation during hypoxia either

Structural and morphological features of Piaractus mesopotamicus (Holmberg, 1887) gills

The pacu Piaractus mesopotamicus (Holmberg, 1887), is a commercially important serrasalmid fish endemic to the Paraná-Paraguay River basin, and one of the most widely cultivated native fish species in the Neotropics. As a migratory species, also inhabiting temporary pools subjected to hypoxic conditions, the species presents a high plasticity concerning respiratory adaptations. In order to supplement basic knowledge on the respiratory physiology and morphology of this species, some structural features of pacu gills, such as filament and lamellae structure, and circulatory pattern are described in this paper

Changes in lactate dehydrogenase and malate dehydrogenase activities during hypoxia and after temperature acclimation in the armored fish, Rhinelepis strigosa (Siluriformes, Loricariidae)

Lactate (LDH) and malate dehydrogenase (MDH) of white skeletal muscle of fishes acclimated to 20, 25 and 30 degrees Celsius and thereafter submitted to hypoxia were studied in different sbstrate concentrations. Significant differences for LDH and MDH of white muscle enzyme activities are described here for the first time in Rhinelepis strigosa of fishes acclimated to 20 degrees Celsius and submitted to hypoxia for six hours. LDH presented a significant decrease in enzyme affinity for pyruvate in acute hypoxia, for fishes acclimated to 20 degrees Celsius and an increase for fishes acclimated to 30 degrees Celsius.

Electrocardiographic characterization of myocardial function in normoxic and hypoxic teleosts

Electrocardiography was applied to analyze cardiac function of four teleost species (Piaractus mesopotamicus, Hoplias malabaricus, Hoplias lacerdae and Cyprinus carpio) during normoxia and graded hypoxia. In these species, hypoxic bradycardia consistently occurred during severe hypoxia (below the critical oxygen tension - PcO2) and was accompanied by alterations in the ECG recordings. Three basic ECG alterations were demonstrable: 1) increase in the T wave area and amplitude, being more positive and with symmetrical morphology during severe hypoxia (P. mesopotamicus); 2) negative T wave in normoxia, changing to isodiphasic (Just above the PcO2) and positive (below the PcO2; H. malabaricus and H. lacerdae); 3) positive T wave in normoxia, changing to negative in severe hypoxia (5 mmHg; Cyprinus carpio). These findings indicate changes in the direction of ventricular repolarization during exposure to severe hypoxia, and the analysis of the ECGs in relation to the derivation line permitted the estimation of these drifts to be 17 degrees in P. mesopotamicus, 46 degrees in H. malabaricus, 43 degrees in H. lacerdae, and 32 degrees in C. carpio. The changes in the direction of ventricular repolarization were attributed to myocardial impairment due to insufficient oxygen supply, and support the idea of a relationship between cardiac dysfunction and the bradycardia developed during severe hypoxia.