Jacek Sadowski

Susceptibility of koi × crucian carp and koi × goldfish hybrids to koi herpesvirus (KHV) and the development of KHV disease (KHVD)

Hybrids of koi, Cyprinus carpio x crucian carp, Carassius carassius and koi x goldfish, Carassius auratus, proved to be susceptible to koi herpesvirus (KHV, syn. CyHV-3) and developed KHV disease (KHVD). While hybrids of koi x goldfish were partly resistant to mortality following infection by immersion, most koi x crucian carp hybrids died after bath infection. KHV DNA was detected in dead fish but also in all surviving animals by different polymerase chain reactions (PCRs). According to these results, hybrid crossbreeding does not seem to prevent severe losses associated with KHV in terms of inducing KHVD. The present study showed severe losses after a waterborne KHV infection of between 35% and 100% in koi x goldfish and koi x crucian carp hybrids as well as in SPF carp.

Koi herpes virus: do acipenserid restitution programs pose a threat to carp farms in the disease-free zones?

In 2003 and subsequent years, a substantial number of Polish fish farms experienced mass mortality of carp (Cyprinus carpio)—their major culture species. Clinical signs have led to the assumption that these heavy losses may have been caused by infection with the koi herpes virus (KHV), which was first isolated and diagnosed in carps from the Rybacka Stacja Doświadczalna (the Fisheries Research Station) of the Agricultural University in Szczecin (Sadowski and Kempter 2004, Bergmann et al. 2006). In the wake of this finding, many research centres in Poland have initiated projects focusing on KHV, in its different aspects, and attempted to develop diagnostic tests for carp cultures (Kempter et al. 2008a). According to the State Veterinary Research Institute in Pulawy (Panstwowy Instytut Weterynaryjny – Panstwowy Instytut Badawczy), this problem is not only related to the carp market and the stocking material turnover. The research projects carried out at the Pulawy institute focuses mainly on the other species, suspected of being a vector for KHV. This assumption is based on the fact that the clinical signs have hitherto not been observed in any other species except Cyprinus carpio (common carp and koi). Many research facilities, such as the the ACTA ICHTHYOLOGICA ET PISCATORIA (2009) 39 (2): 119–126 DOI: 10.3750/AIP2009.39.2.06

Genetic variability in European populations of Coregonus lavaretus (L.): an assessment based on mitochondrial ND-1 gene haplotypes

Genetic variability in European populations of Coregonus lavaretus (L.): an assessment based on mitochondrial ND-1 gene haplotypes The genetic variability of whitefish, Coregonus lavaretus (L.), was studied based on 114 individuals from nine populations inhabiting Polish lakes, including the Szczecin Lagoon, and from one population each from lakes in Austria and Switzerland. Differences within and among populations were assessed with mitochondrial ND-1 gene sequences that were PCR amplified and digested with ten restriction enzymes. The ten composite haplotypes obtained were sequenced and analyzed with MEGA4 software. The highest intrapopulation variability was noted in the whitefish populations inhabiting lakes Ińsko, Miedwie, Marianowo, Wisola, Śremskie, Morzycko, the Szczecin Lagoon, and Lake Lucerne, which possessed from two to five composite haplotypes. In contrast, populations inhabiting lakes Woświn, Czarne, and Traunsee were fixed for the most common haplotype H2. Zróżnicowanie genetyczne europejskiej populacji Coregonus lavaretus (L.): ocena na podstawie mitochondrialnego genu ND-1 Zróżnicowanie genetyczne 9 populacji siei pospolitej (Coregonus lavaretus, L.) określono w grupie 114 osobników pozyskanych ze zbiorników wodnych Polski, Szwajcarii oraz Austrii. Analizę przeprowadzono w oparciu o technikę PCR-RFLP zastosowaną względem mitochondrialnego genu ND-1, którego sekwencję poddano trawieniu 10 enzymom restrykcyjnym. Na tej podstawie otrzymano dziesięć haplotypów, których sekwencje reprezentatywne zostały poddane sekwencjonowaniu oraz analizie z wykorzystaniem programu MEGA4. Najwyższe zróżnicowanie międzypopulacyjne określono dla populacji siei zamieszkujących jeziora Ińsko, Miedwie, Marianowo, Wisola, Śremskie, Morzycko, Zalew Szczeciński oraz szwajcarskie jezioro Lucerne. Zawierały się ona w obrębie haplotypów od 2 do 5. Dla porównania osobniki z jezior Woświn, Czarne (DPN) oraz Traunsee (Austria) były zaklasyfikowane do pojedynczego haplotypu H2.

Genetic structure of the whitefish (Coregonus lavaretus) population inhabiting the Miedwie Lake, Poland, based on partial ND-1 and ITS-1 gene sequences

The aim of this study was to characterize whitefish and peled populations in Miedwie Lake by means of the genetic analysis of ND-1 (NADH dehydrogenase 1) gene and the ITS-1 (internal transcribed spacer 1) region in order to distinguish native forms from whitefish/peled hybrids. In the analysis, archival specimens of Coregonus lavaretus maraena from the Berlin Museum für Naturkunde were used. Genetic analysis performed with the aid of MEGA 4.0 software explicitly indicated that samples from Miedwie Lake belonged entirely to a native (rapidly growing) form of whitefish. Furthermore, the conducted research has also provided crucial information for a C. lavaretus management program for Miedwie Lake.