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The influence of nanoparticles (NPs) on aquatic environments is still poorly documented. The aim of the study was to determine the effects of silver (AgNPs) and copper (CuNPs) nanoparticles on larval Siberian sturgeon (Acipenser baerii) after 21 days of exposure. Acute toxicity of AgNPs on Siberian sturgeon was investigated in a 96-h static renewal study and compared with the toxicity of CuNPs. The AgNPs and CuNPs 96 h mean lethal concentrations (96 h LC50) were 15.03 ± 2.91 and 1.41 ± 0.24 mg L−1, respectively. Toxicity tests were done in triplicates for each concentration of AgNPs 0.1, 0.5, 1.5 mg L−1 and CuNPs 0.01, 0.05, 0.15 mg L−1. The control group was exposed in freshwater. The results indicate that AgNPs and CuNPs exposure negatively influenced survival; body length and mass; and morphology and physiology of the epidermis, gills, and liver of Siberian sturgeon larvae. Fish exposed to AgNPs and CuNPs showed similar pathological changes: irregular structure and pyknotic nuclei of epidermis, aplasia and/or fusion of lamellae, telangiectasis, epithelial necrosis and lifting of the gills, dilation of sinusoidal space, overfilled blood vessels, and pyknotic nuclei of the liver. Fish exposed to CuNPs only demonstrated hyaline degeneration in the gills epithelium and liver. The study shows that CuNPs were more toxic to Siberian sturgeon larvae than AgNPs.

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Platinum nanoparticles (NP-Pt) are noble metal nanoparticles with unique physiochemical properties that have recently elicited much interest in medical research. However, we still know little about their toxicity and influence on general health. We investigated effects of NP-Pt on the growth and development of the chicken embryo model with emphasis on brain tissue micro- and ultrastructure. The embryos were administered solutions of NP-Pt injected in ovo at concentrations from 1 to 20 μg/ml. The results demonstrate that NP-Pt did not affect the growth and development of the embryos; however, they induced apoptosis and decreased the number of proliferating cells in the brain tissue. These preliminary results indicate that properties of NP-Pt might be utilized in brain cancer therapy, but potential toxic side effects must be elucidated in extensive follow-up research.

Early gonadal development in Russian (Acipenser gueldenstaedtii Brandt, 1869) and Siberian sturgeon (Acipenser baerii Brandt & Ratzeburg, 1833) reared in controlled conditions from dph 1-439 (days post hatching) was studied using histological methods. Migrating primordial germ cells (PGCs) were observed in both species on dph 1. On dph 25 in both species gonad primordia developed in gonadal ridges. In dph 115 juveniles two types of gonad were distinguished, putative ovary and putative testicle. Meiotic activity was observed in ovaries on dph 197, while in testicles the first meiotic divisions were observed much later, on dph 439 and only in several Siberian specimens. The presence of Vasa protein was confirmed exclusively in germ cells during gonadogenesis, indicating that Vasa is a good marker of germinal cells also in Acipenseridae. Vasa protein displayed a nuage association or nuage-like localization. Some differences in the level of Vasa protein expression during male and female gonad development were also observed. In the gonads of both investigated sturgeon species the PCNA (proliferating cell nuclear antigen)-positive reaction was observed first in oogonia, while in spermatogonia at approximately 115 dph which was correlated with active mitotic divisions of germ cells. Surprisingly, meiotic oocytes arrested in diplotene also demonstrated strong PCNA-positive germinal vesicle.

The present study evaluated the performance of two commercial diets: AgloNorse (AN) and BioKyowa (BK), and two experimental, formulated diets based on casein (C) or casein plus casein hydrolysates (CH) in rearing of pike-perch larvae (Sander lucioperca L.). All ¢sh were 5 day old and control group was fed live Artemia nauplii. Fish were sampled periodically for histological comparison of morphological changes in the digestive tracts. Survival of ¢sh fed Artemia nauplii, BK and AN was similar: 54.4%, 50.8% and 52.4%, respectively, while the ¢sh fed formulated diets C and CH showed considerably lower survival: 28.4% and 21.6% respectively. After 5 weeks of rearing, the average body mass of ¢sh ranged from 212 AE 32 mg in Artemia fed group to 53.8 AE 6.8 mg in C diet fed group.A considerable vacuolization of supranuclear zone in enterocytes of posterior intestine was observed in the larvae fed commercial diets. No anomalies in liver development were found. Hepatocytes of ¢sh fed BK diet showed larger glycogen storage areas, compared with those occupied by lipids. The highest zymogen accumulation of pancreatic cytoplasm was observed in ¢sh fed Artemia. In ¢sh fed C and CH diets, anomalies in digestive system development were indicated by lower and less numerous intestinal folds, smaller hepatocytes, retarded development of gastric glands, and in CH group^also local fatty degeneration of liver.

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