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Exotic species of acipenserid fishes have been frequently encountered in the commercial catches of the Baltic Sea, since the early 1990s. Such sightings are rarely reflected as published records. The present paper provides detailed descriptions of two specimens of Russian sturgeons, Acipenser gueldenstaedtii caught in the Exclusive Polish Economic Zone of the Baltic Sea.
Sturgeon frywere obtained through the artificial spawning of Siberian sturgeon (Acipenser baeri Brandt) and the hybrid of Siberian and Russian sturgeon (Acipenser baeri Brandt x Acipenser gueldenstaedti Brandt). Selected biotechnological factors of the fish were compared and biometric measurements were taken during a 60-day long rearing period in a recirculation system. A higher growth rate was confirmed in the hybrid sturgeon. The average body weight of the hybrid at an age of nine months was 1,078 g, while that of the Siberian sturgeon was 872 g. The hybrid also utilized feed more efficiently. The food conversion rate during the study period was 0.64 for the hybrid and 0.66 for the Siberian sturgeon. The greatest differences in the plastic features of the studied fish were found for those related to the head. The Siberian sturgeon had a longer rostrum (R) and a shorter post-orbital space (op) than did the hybrid. Significant differences were also observed in the numbers of lateral bony plates (Sl), the number of rays in the dorsal fins (D) and the number of rays in the anal fins (A).
Background. Sturgeons have long been extinct in Polish inland waters. A substantial effort has recently been put into their restitution, covering the drainage areas of two major Polish rivers, the Oder and the Vistula. The stocked fishes are clinically healthy, but very little is known about their potential to transmit viral diseases including koi herpes virus (KHV) to healthy fishes of other species, which may pose a threat to the disease-free zones. This study was intended to determine if sturgeons could be asymptomatic carriers of KHV. Materials and Methods. A total of 29 sturgeons (two species; length 8–37 cm) originating from fish farms in northern Poland with a known KHV history in common carp or koi in the area were examined: 15 Russian sturgeons, Acipenser gueldenstaedtii, with clinical signs of a disease and 14 asymptomatic Atlantic sturgeons, A. oxyrinchus. The former were sent to the laboratory alive while the latter were sent fixed in ethanol. As it is required for detection of a latent KHV infection in acipenserids, two independent procedures were applied. The preliminary results were obtained using PCR. Those findings were subsequently confirmation by nested PCR. The latter procedure consists of sequence analysis of PCR products and direct detection of KHV infected cells in tissue materials by in-situ hybridization on nucleic acid level or indirect immunofluorescence on KHV protein level. Results. KHV genome parts were found in nine Russian sturgeons and four Atlantic sturgeons. Comparison of PCR results obtained from three primer pairs used for KHV diagnostic in sturgeon showed that those designed by Bercovier et al. were most sensitive and robust for this purpose. In order to confirm the presence of viral particles the most useful method was in-situ hybridization (ISH), allowing the detection of KHV in gill samples obtained from live sturgeons. Conclusion. This preliminary study shows that sturgeons can be carriers of KHV. Therefore a viral diagnostics is highly recommended not only for sturgeons obtained from the environment but also for fertilized eggs, fry, and fish intended for re-stocking measurements of inland waters.
The aim of the studies was to determine the impact of the feed supplement Vitaton, a preparation containing b-carotene, on the growth rate, feed utilization, and meat quality of reciprocal back cross hybrids of Siberian sturgeon, Acipenser baerii Brandt × green sturgeon, Acipenser medirostris Ayres, (SSZ group) and Siberian sturgeon × Russian sturgeon, Acipenser gueldenstaedti Brandt, (SRS group). It was confirmed that b-carotene results in a statistically significant increase in growth rate of about 20% and a decrease in the value of the feed conversion ratio (FCR) by 9.6% in the fish from the SSZ group. Statistically significant differences between the Vitaton and control subgroups in the SRS group occurred only with regard to the FCR at values of 1.64 ± 0.08 and 1.71 ± 0.09, respectively. The results of meat quality tests indicated that under the influence of Vitaton there was a statistically significant increase in the fat content to 13.21 ± 1.04% in comparison with the control group values of 9.57 ± 2.33% and a decrease in the water content from 72.73 ± 1.57% to 68.82 ± 1.28% in the fish from the SRS group. No significant impact of b-carotene was noted in the studied fish with regard to meat color.
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