Browsing by Subject "RAINBOW-TROUT"

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  • Kotrschal, Alexander; Lievens, Eva J. P.; Dahlbom, Josefin; Bundsen, Andreas; Semenova, Svetlana; Sundvik, Maria; Maklakov, Alexei A.; Winberg, Svante; Panula, Pertti; Kolm, Niclas (2014)
  • Vuorinen, Pekka J.; Rokka, Mervi; Ritvanen, Tiina; Käkelä, Reijo; Nikonen, Soili; Pakarinen, Tapani; Keinänen, Marja (2020)
    Salmonines in the Baltic Sea and North American lakes suffer from thiamine (vitamin B1) deficiency, which is connected to an abundant lipid-rich diet containing substantial amounts of polyunsaturated fatty acids (PUFAs). In the Baltic region, this is known as the M74 syndrome. It affects both adult salmon (Salmo salar) and especially their offspring, impairing recruitment. However, very little is known about the thiamine and lipid metabolism of salmon during feeding and spawning migrations in the Baltic Sea. In this study, salmon females were sampled along the spawning run from the southern Baltic Proper in four locations at sea and finally at spawning in a river at the Bothnian Bay in a year with insignificant M74 mortality. Changes in concentrations of thiamine and its components in muscle, ovaries, and the liver and other biochemical indices potentially relating to lipid and fatty acid metabolism were investigated. The results provide further evidence of the role of peroxidation of PUFAs in eliciting thiamine deficiency in salmon: During the entire spawning run, the muscle total lipid content decreased by 50%, palmitic acid (16:0) by 62%, and docosahexaenoic acid (DHA, 22:6n-3) by 45%. The concentration of total thiamine decreased significantly until the spawning in the liver and ovaries, 66 and 70% respectively. In the muscle, the proportion of thiamine pyrophosphate of total thiamine increased with the use of muscular lipid stores. There was no trend in the concentration of total carotenoids during the spawning run. The doubling of the concentration of hepatic malondialdehyde indicated peroxidation of PUFAs, and the mobilisation of body lipids suppressed the activity of glucose-6-phosphate dehydrogenase, as consumed dietary lipids would also have done.
  • Monzon-Argueello, Catalina; Consuegra, Sofia; Gajardo, Gonzalo; Marco-Rius, Francisco; Fowler, Daniel M.; De Faveri, Jacquelin; de Leaniz, Carlos Garcia (2014)
  • Zueva, Ksenia J.; Lumme, Jaakko; Veselov, Alexey E.; Kent, Matthew P.; Primmer, Craig R. (2018)
    Abstract Understanding the genomic basis of host-parasite adaptation is important for predicting the long-term viability of species and developing successful management practices. However, in wild populations, identifying specific signatures of parasite-driven selection often presents a challenge, as it is difficult to unravel the molecular signatures of selection driven by different, but correlated, environmental factors. Furthermore, separating parasite-mediated selection from similar signatures due to genetic drift and population history can also be difficult. Populations of Atlantic salmon (Salmo salar L.) from northern Europe have pronounced differences in their reactions to the parasitic flatworm Gyrodactylus salaris Malmberg 1957 and are therefore a good model to search for specific genomic regions underlying inter-population differences in pathogen response. We used a dense Atlantic salmon SNP array, along with extensive sampling of 43 salmon populations representing the two G. salaris response extremes (extreme susceptibility vs resistant), to screen the salmon genome for signatures of directional selection while attempting to separate the parasite effect from other factors. After combining the results from two independent genome scan analyses, 57 candidate genes potentially under positive selection were identified, out of which 50 were functionally annotated. This candidate gene set was shown to be functionally enriched for lymph node development, focal adhesion genes and anti-viral response, which suggests that the regulation of both innate and acquired immunity might be an important mechanism for salmon response to G. salaris. Overall, our results offer insights into the apparently complex genetic basis of pathogen susceptibility in salmon and highlight methodological challenges for separating the effects of various environmental factors.
  • Vennerström, Pia; Maunula, Leena; Välimäki, Elina; Virtala, Anna-Maija (2020)
    After the first outbreak of viral haemorrhagic septicaemia virus (VHSV) in Finnish brackish water rainbow trout Oncorhynchus mykiss farms, infection spread rapidly between the farms. The infrastructure of fish farming did not take into account spreading of infectious fish diseases. To show the presence of VHSV in the environment, we tested seawater, sediment and wild blue mussels Mytilus edulis from VHSV-infected fish farms, and liquid waste from a processing plant that handled infected rainbow trout. Additionally, blue mussels were bath-challenged with VHSV (exposed to cultivated virus or naturally infected rainbow trout). To detect VHSV, virus isolation in cell culture and real-time reverse transcriptase polymerase chain reaction (qRT-PCR) were used. The virus or viral RNA was detected in sea water and in liquid waste from processing plants during wintertime when water temperature is close to 0 degrees C and sunlight is sparse. VHSV did not appear to replicate in blue mussels in our study. Therefore, blue mussels were not considered relevant carriers of VHSV. However, traces of viral RNA were detected up to 29 d post challenge in mussels. Contact with water from processing plants handling VHSV-infected fish populations increases the risk of the disease spreading to susceptible fish populations, especially during cold and dark times of the year.
  • Aalto-Araneda, Mariella; Korkeala, Hannu; Lundén, Janne (2018)
    Vacuum-packaged cold-salted and cold-smoked fish products are considered typical vehicles for Listeria monocytogenes, the causative agent of the food-borne disease listeriosis, which is increasingly prevalent in the European Union. Efficacy of both the fish processing plant self-checking system and official food control conducted by authorities are crucial for L. monocytogenes prevention in the processing of these risky products. However, the impact of official control on L. monocytogenes prevention in the processing of fish products has not been extensively studied. We investigated the occurrence, control measures, and correction of non-compliances predisposing to L. monocytogenes in Finnish fish processing plants. The following features were associated with L. monocytogenes occurrence: (a) frequency of non-compliances concerning processing machinery, (b) recurrence of non-compliances, and (c) frequency of non-compliances for which official control measures were requested by inspecting authorities. Official control of fish processing plants had focused on risky areas, but non-compliances were common and their correction exhibited deficiencies. We conclude that L. monocytogenes prevention in fish processing can be enhanced by strengthening official food control measures and processing plant compliance. In particular, timely correction of all food safety violations must be improved.
  • Vennerström, Pia; Välimäki, Elina; Lyytikäinen, Tapani; Hautaniemi, Maria; Vidgren, Gabriele; Koski, Perttu; Virtala, Anna-Maija (2017)
    The eradication of viral haemorrhagic septicaemia virus (VHSV Id) from Finnish brackish-water rainbow trout Oncorhynchus mykiss farms located in the restriction zone in the Province of angstrom land, Baltic Sea, failed several times in the 2000s. The official surveillance programme was often unable to find VHSV-positive populations, leading to the misbelief in the fish farming industry that virus eradication could be achieved. The ability of 3 other surveillance programmes to detect infected fish populations was compared with the official programme. One programme involved syndromic surveillance based on the observation of clinical disease signs by fish farmers, while 2 programmes comprised active surveillance similar to the official programme, but included increased sampling frequencies and 2 additional tests. The syndromic surveillance concentrated on sending in samples for analysis when any sign of a possible infectious disease at water temperatures below 15 degrees C was noticed. This programme clearly outperformed active surveillance. A real-time reverse transcriptase-polymerase chain reaction method proved to be at least as sensitive as virus isolation in cell culture in detecting acute VHSV infections. An ELISA method was used to test fish serum for antibodies against VHSV. The ELISA method may be a useful tool in VHSV eradication for screening populations during the follow-up period, before declaring an area free of infection.
  • Vennerström, Pia; Välimäki, Elina; Hautaniemi, Maria; Lyytikainen, Tapani; Kapiainen, Suvi; Vidgren, Gabriele; Virtala, Anna-Maija (2018)
    Wild fish were suspected to be the source of reinfection by viral haemorrhagic septicaemia virus (VHSV) in Finnish brackish water rainbow trout farms located in a restriction zone regarding viral haemorrhagic septicaemia (VHS) comprising the entire Province of Aland, Baltic Sea, in the 2000s. Altogether, 1636 wild fish of 17 different species living in the vicinity of infected fish farms were screened for VHSV during the years 2005-2008. Additionally, 2 uninfected wild fish species as well as farmed whitefish were introduced into a VHS-positive fish farm to test whether they became infected by VHSV from the clinically diseased rainbow trout. Wild fish did not test positive for VHSV on any occasion. In contrast, whitefish introduced to a VHS-positive farm were infected with VHSV genotype Id and started to replicate the virus for a short time during the trial. Whitefish are farmed together with, or in the vicinity of, farmed rainbow trout in the study area and, according to this study, are a possible source of the recurring infection in the restriction area. A sprivivirus was isolated from all fish species in the infection trial without causing mortality in the test groups.