The distribution of Neuropeptide Y-immunoreactive neurons and nerve fibers in the forebrain of the carp Cyprinus carpio L.

The present study reports the distribution of Neuropeptide Y (NPY)-immunoreactive neurons and fibers in the forebrain of the adult carp Cyprinus carpio L.. Serial Nissl-stained sections were used for cytoarchitecture and identification of anatomical structures. Immunostaining of NPY-containing neurons and fibers was used as neurochemical marker and tool for comparison with other species, including the goldfish.The general outline of the cytoarchitecture of the carp forebrain is similar to that of other Cypriniformes. However, using NPY immunohistochemistry, we found several specific differences with the goldfish, especially in the diencephalon. In the hypothalamus of the carp NPY-immunoreactive (NPYir) neurons were identified in the n. dorsolateralis thalami, and in the n. ventralis lateralis thalami. In the same location, we observed the n. anterior hypothalami and the n. preglomerulosus pars lateralis, described in the goldfish, as parts of n. prerotundus. However, in the carp we were not able to identify a n. preglomerulosus pars medialis, a n. preglomerulosus pars medialis commissuralis and a n. glomerulosus. We describe a n. rotundus, in which we did not find substructures typical of the goldfish.Further differences with the goldfish, trout and salmon were also noted.     

A direct cerebello-telencephalic projection in an electrosensory mormyrid fish

After injections of the posterior part of the lateral zone of the area dorsalis telencephali (Dlp) with either horseradish peroxidase or the newly available carbocyanine dye DiI, efferent cells were labeled in the valvula cerebelli of the mormyrid fish,Gnathonemus petersii. This may be a unique connection for this group of electrosensory teleosts, since no other vertebrate has ever been reported before to have a direct cerebello-telencephalic projection.     

Ultrastructure of hepatocytes in golden ide (Leuciscus idus melanotus L.; Cyprinidae: Teleostei) during thermal adaptation

Summary The morphological alterations of hepatocytes of golden ide, Leuciscus idus melanotus, following adaptation to low and high temperatures (14 and 28°C) were investigated by means of light and electron microscopy. The temperature-dependent behaviour of peroxisomes was visualized cytochemically with the alkaline diaminobenzidine medium; the morphological studies were supplemented by the biochemical determination of catalase activity.Cold adaptation of ide hepatocytes is manifested by proliferation and stacking of endoplasmic reticulum, an enhanced secretory activity of Golgi fields and a higher number of peroxisomes as compared with the warmadapted animals. The latter organelles are characterized by a marked heterogeneity in size, shape and catalase activity, and by a more intimate association with mitochondria and endoplasmic reticulum. The occurrence of small peroxisomal profiles is restricted to lower temperature. Catalase activity can be shown both cytochemically and biochemically to increase during cold adaptation.Whereas the number of mitochondria seems to be unaffected by thermal adaptation, stacking of mitochondria as well as the formation of intramitochondrial membrane piles indicate cold-adaptive processes.A feature typical of warm-adaptation is the formation of membrane-glycogen complexes, which may represent the morphological expression of enhanced carbohydrate metabolism documented in a decreased storage of glycogen at 28°C. At 28°C lipid is the predominant storage product.These findings indicate that fish liver is well-suited to serve as a model for the analysis of the interaction of environmental temperature conditions and hepatic morphology.     

Vaccination of grouper broodfish (Epinephelus tukula) reduces the risk of vertical transmission by nervous necrosis virus

Nervous necrosis virus (NNV) has caused mass mortality in many species of cultured fish at larval stage. Strong evidence of vertical transmission of NNV has been reported in the carrier broodstock of striped jack and sea bass. An effective immunization program was developed and monitored in adult groupers (Epinephelus coioides) with average body weight of 1.35 kg. The highest neutralizing antibody titers were found in the fish intramuscularly injected with adjuvanted NNV vaccine at 10⁹ TCID₅₀ kg⁻¹, and the enhanced 2-fold neutralization activity could sustain up to 17 months post-vaccination (mpv). An immunization program was applied in the broodstocks of grouper (Epinephelus tukula) with body weight of 35–60 kg. The levels of NNV-specific antibodies detected, from 1 to 5 mpi, in the homogenates of the eggs from the vaccinated broodfish were elevated than that from non-vaccinated fish. By nested RT-PCR, NNV was detectable in the eggs from the non-vaccinated fish at Month 5, but not in the eggs from vaccinated fish. It is therefore suggested that vaccination will be a potentially practical measure to reduce the risk of vertical transmission of NNV of grouper broodfish under stress of repeated spawning.     

Effects of Acute Exposure to Metribuzin on Some Hematological,Biochemical and Histopathological Parameters of Common Carp (Cyprinus carpio L.)

The aim of the study was to evaluate acute toxic effects of the preparation Sencor 70 WG (metribuzin 70% W/V) on hematological, biochemical indices and histology of the common carp (Cyprinus carpio L.). In carp exposed for 96 h to Sencor 70 WG in the concentration of 250.2 mg/L, showed significantly lower (p < 0.01) values of plasma total proteins, albumins, total globulins, triacylglycerols, lactate dehydrogenase, lactate, inorganic phosphate, hematocrit, hemoglobin concentration, mean erythrocyte volume, the leucocrite value, lymphocyte, and significantly higher (p < 0.01) values of glucose, ammonia, calcium, monocytes, neutrophile granulocytes, developmental forms myeloid sequence and basophiles compared to the control group. Histopathological examination revealed hyaline degeneration of the epithelial cells of renal tubules of the caudal kidney. This alteration of kidney resulted in hypoproteinemia, followed by generation of transudate in body cavity.     

Biomonitoring of mercury and persistent organic pollutants in Michigan urban anglers and association with fish consumption

The 32-mile Detroit River and surrounding tributaries have been designated as a Great Lakes Area of Concern due to pollution from decades of municipal and industrial discharges, sewer overflows and urban development. Key pollutants in fish samples from the Detroit River include mercury, polychlorinated biphenyls (PCBs), dichlorodiphenyldichloroethylene (DDE), dioxins and furans. A biomonitoring study was conducted to assess exposures to these persistent toxic substances in Detroit urban shoreline anglers who may be at high exposure risk due to consumption of locally caught fish. Using a modified venue-based sampling approach, 287 adult shoreline anglers along the Detroit River were recruited and participated in the program. Study participants provided blood and urine specimens and completed a questionnaire following informed consent. We examined percentile estimates for total blood mercury, PCBs, DDE, and dioxin-like total toxic equivalency (TEQ) concentrations among study participants. Multiple linear regression was used to identify important predictors of contaminant concentrations. Participants consumed a median of 64 Detroit River caught fish meals in the past year. The Detroit urban anglers’ median total blood mercury concentrations was 3.2 times higher than that for the general adult U.S. population. PCB concentrations among the Detroit anglers aged 18–39 years were higher than the U.S. population of the same race/ethnicity. Elevated levels of DDE and total TEQ concentrations were not observed in the cohort. Eating more locally caught fish was associated with higher total blood mercury and serum PCB concentrations. The biomonitoring data served to inform public health officials and help guide environmental public health actions to reduce harmful exposures.