Next-generation salmonid alphavirus vaccine development
Hikke, M.C. - \ 2016
Wageningen University. Promotor(en): Just Vlak, co-promotor(en): Gorben Pijlman. - Wageningen : Wageningen University - ISBN 9789462577404 - 159
alphavirus - atlantic salmon - rainbow trout - vaccine development - immunity - virology - fish culture - aquaculture - biotechnology - alfavirus - europese zalm - regenboogforel - vaccinontwikkeling - immuniteit - virologie - visteelt - aquacultuur - biotechnologie
Aquaculture is essential to meet the current and future demands for seafood to feed the world population. Atlantic salmon and rainbow trout are two of the most cultured aquaculture species. A pathogen that threatens these species is salmonid alphavirus (SAV). A current inactivated virus vaccine against SAV provides cross-protection against all SAV subtypes in salmonids and reduces mortality amongst infected fish. However, protection is not 100% and due to virus growth at low temperature, the vaccine production process is time consuming. In addition, the vaccine needs to be injected into the fish, which is a cumbersome process. The work described in this thesis aimed to increase the general knowledge of SAV and to assess current vaccine technologies, and to use this knowledge in designing next-generation vaccines for salmonid aquaculture.
An alternative cell line to support SAV proliferation was identified, however, the virus production time could not yet outcompete the current SAV production system. Making use of the baculovirus insect cell expression system, multiple enveloped virus-like particle (eVLP), and core-like particle (CLP) prototype vaccines were produced in insect cells at high temperature. An in vivo vaccination study showed, however, that these vaccines could not readily protect Atlantic salmon against SAV. The low temperature-dependent replication of SAV was attributed to the glycoprotein E2, and it was found that E2 only correctly travelled to the cell surface at low temperature, and in the presence of glycoprotein E1. The biological impact of this finding was confirmed in the development and in vivo testing of a DNA-launched replicon vaccine. The effective DNA-launched replicon vaccine was extended by delivery of the capsid protein in trans. It was hypothesized that viral replicon particles (VRP) were formed in vivo, which would cause an additional single round of infection and might further elevate the immune response in comparison to the replicon vaccine. A second animal trial indicated that the inclusion of capsid did not yet improve vaccine efficacy. This trial however did show that a DNA vaccine transiently expressing the SAV structural proteins provided superior protection over both replicon vaccines (with and without capsid).
In this thesis, some virus characteristics, such as the cause of temperature-dependency of SAV replication, of an unique aquatic virus were further explored. The production and in vivo testing of multiple next-generation vaccines defined the prerequisites for induction of a potent immune response in Atlantic salmon. A prototype DNA-launched replicon vaccine has shown potential for further development. The research described in this thesis contributes to the development of next-generation vaccines in the challenging area of fish vaccinology.
Scoping study Turkish Rainbow trout aquaculture
Schram, E. - \ 2016
IJmuiden : IMARES (Report / IMARES C005/16) - 19
rainbow trout - recirculating aquaculture systems - fish culture - industry - stakeholders - companies - feasibility studies - turkey - regenboogforel - recirculatie aquacultuur systemen - visteelt - industrie - stakeholders - kapitaalvennootschappen - haalbaarheidsstudies - turkije
One size fits all? : optimization of rainbow trout breeding program under diverse preferences and genotype-by-environment interaction
Sae-Lim, P. - \ 2013
Wageningen University. Promotor(en): Johan van Arendonk, co-promotor(en): Hans Komen; A. Kause. - S.l. : s.n. - ISBN 9789461734648 - 200
regenboogforel - dierveredeling - veredelingsprogramma's - genotype-milieu interactie - optimalisatie - kenmerken - genetische winst - selectief fokken - simulatie - visteelt - aquacultuur - rainbow trout - animal breeding - breeding programmes - genotype environment interaction - optimization - traits - genetic gain - selective breeding - simulation - fish culture - aquaculture
Global fish breeders distribute improved animal material to several continents to be farmed under diverse environments, and for very different market conditions. When establishing a global breeding program, there is a need to assess whether or not a single breeding objective satisfies the markets across different countries. It may be challenging to develop a single fish stock that performs well across all environments due to genotype-by-environment interaction (GxE). GxE is a phenomenon describing the possibility that different genotypes have a different sensitivity to changes in an environment. The objective of this thesis was to develop an optimized global breeding program for rainbow trout (Oncorhynchus mykiss) in terms of a balanced breeding goal that satisfies preferences of trout producers and maximized genetic gains across environments in the presence of GxE in production traits. Analytic hierarchy process (AHP) was used to estimate preferences, which can be aggregated to consensus preference values using weighted goal programming (WGP). The analysis revealed that the 6 most important traits were thermal growth coefficient (TGC), survival (Surv), feed conversion ratio (FCR), condition factor (CF), fillet percentage (FIL%), and late maturation (LMat). Individual trait preferences are different for farmers having different farming environments and producing different end-products. Calculating consensus preference values resulted in consensus desired genetic gains. To satisfy most farmers, consensus desired genetic gains can be taken into account in a global breeding strategy. Strong genotype re-ranking was found for all growth traits across environments. Based on simulation, re-location of breeding program led to highest total genetic gain for body weight at harvest. Alternatively, including sib performance into selection index increased genetic gain in all environments. Finally, environment-specific program can be used, but this is costly. There is a possibility of a conflict between 2 profits: from a breeding company and fish farmers and an optimum solution for that conflict can be found by using macroeconomics and cost-benefit analysis.