Two new species of Sciadicleithrum are described from the gills of Neotropical cichlid fishes collected from Paraná River, Brazil. Sciadicleithrum satanopercae sp. nov. is described from the gills of Satanoperca pappaterra and differs from congeners by having a dorsal anchor with the distal portion complex and the inner margin with a “denticulum” between shaft and point. Sciadicleithrum joanae sp. nov. is described from the gills of Crenicichla niederleinii and C. britskii collected from Paraná River. Sciadicleithrum joanae sp. nov. differs from congeners by having a male copulatory organ comprising about half a clockwise loop and a vaginal pore “bulb-shaped”.
Antioxidant defence system (activities of superoxide dismutase, catalase, glutathione reductase, and glutathione peroxidase), and free radical modification of lipids were determined in the gills from male and female brown trout (Salmo trutta m. trutta L.) affected by ulcerative dermal necrosis (UDN). In both males and females, lipid oxidation in the gills from UDN-affected trout showed higher values as compared to the respective control. UDN induced an increase of thiobarbituric acid reactive substances (TBARS) levels both in the gills of males and females. UDN caused a decrease in gill antioxidant enzyme activities. This might be due to inactivation of the abovementioned enzymes by the end products of lipid peroxidation. The importance of the glutathionemediated antioxidant defence system in protection against UDN-induced oxidative stress was demonstrated.
The aim of this study was to assess the effect of oral vaccination against Yersinia ruckeri based on oxidative stress biomarkers in different tissues of rainbow trout (Oncorhynchus mykiss Walbaum). Vaccine consisted of three Y. ruckeri strains (O1 serotype) that originated from rainbow trout cultured on the different farms, where fish exhibited clinical signs of enteric redmouth disease. Concentrated vaccine was incorporated in the fish food; treatment was delivers three times at one day intervals. One month after immunization, gills, hepatic and cardiac tissues were sampled. The vaccinated trout showed tissue-specific oxidative stress responses in the gills, liver, and heart. The gill tissue was the most sensitive to oxidative damage among the samples. Accumulation of oxidative stress biomarkers in the rainbow trout was tissue-specific with following accumulation: gills > heart > liver. These results suggest that the trout expressed tissue-specific oxidative stress mechanisms due to anti- Yersinia vaccine treatment. There were no statistically significant alterations in the activities of antioxidant defenses instead superoxide dismutase activity in the hepatic and cardiac tissue and glutathione peroxidase activity in the gills of vaccinated trout. Correlative analysis confirmed the role of catalase in the antioxidant defense in vaccinated trout. The oxidative stress biomarkers, i.e. content of oxidative modified proteins in the gills, and liver, and 2-thiobarbituric acid reactive substances level in the gills, and total antioxidant capacity in the liver, were sensitive to vaccination of trout against Y. ruckeri and may potentially be used as biomarkers in evaluating vaccine toxicity in rainbow trout.
Unilatus irae sp. nov. (Dactylogyridae) is described from the gills of the armored catfish, Leporacanthicus galaxias Isbrücker et Nijssen (Loricariidae: Ancistrinae), from Guamá river, Pará State, Brazil. The new species can be differentiated from its cogeneners by the combination of the following features: anterior anchor with well-developed superficial root, inconspicuous deep root, shaft bent at midpoint, forming angle of approximately 60°, evenly short curved point; posterior anchor with inconspicuous roots, sclerotized cap of base with small protuberance for articulation to posterior bar; evenly curved shaft and short point; anterior bar broadly V-shaped, with small posteromedial projection; and posterior bar anteriorly expanded on it midportion, with expanded ends slightly curved in posterior direction.