Projects / Programmes
Immune response and behaviour of domesticated and wild brown trout
| Code |
Science |
Field |
Subfield |
| 4.02.01 |
Biotechnical sciences |
Animal production |
Genetics and selection |
| Code |
Science |
Field |
| B402 |
Biomedical sciences |
Aquaculture, pisciculture |
| Code |
Science |
Field |
| 1.06 |
Natural Sciences |
Biological sciences |
brown trout, hybridization, selection, fisheries, stocking, genetic diversity, immune response, stress, resistance, behaviuor
Researchers (1)
| no. |
Code |
Name and surname |
Research area |
Role |
Period |
No. of publicationsNo. of publications |
| 1. |
22445 |
PhD Andrej Razpet |
Biotechnology |
Head |
2010 - 2012 |
64 |
Organisations (1)
Abstract
BACKGROUND: Salmonid fish species are hatchery-reared for consumption and for stocking managed freshwater streams for sport fishing. Stocking can be used as a mean to increase the population size or to restore native population. Domesticated brown trout (Salmo trutta) originates from European rivers flowing in the North Atlantic Ocean, more precisely from anadromous type of brown trout that is capable of living and reproducing in the sea water. Although not native to Slovenia, these fish hybridise with native brown and marble trout (S. marmoratus), reducing their genetic diversity. Repopulation of marble trout is an ongoing successful project in the Slovenian part of the Adriatic drainage that started from eight genetically pure marble trout populations. A similar project in the Slovenian part of the Danubian drainage has yet to take place as no suitable genetically pure populations were found so far. Most populations of brown trout in the Danubian drainage are therefore hybrids between native brown trout and non-native domesticated brown trout. The level of introgression can be assessed with genetic markers. PROBLEM: Hatchery-reared brown trout have a low survival rate after stocking and wild brown trout have low survival rate in fish farms. Adaptation to the new environment is made difficult because of the acquired behaviour in the wild/captivity, but low survival rate is maintained even after a few generations, meaning that the reason for the phenomena is at least partially genetic. The most probable explanation for the genetic component is the difference between selection pressure in the wild and in captivity. In hatcheries and fish farms most fertilised eggs hatch successfully meaning that the selection pressure is low. Fish used for stocking have to be able to adapt, survive and reproduce in managed streams. The purpose of this research project is to find differences between wild and domesticated brown trout in their genetic diversity, immune response, tolerance of embryos to infection and behaviour in captivity in order to improve conditions and selection in captivity in a way to maximize survival rate of fish after release. METHODS: Genotypization of microsatellite and MHC loci will be performed on DNA isolated from fin clips. Expression analysis of immune response and stress related genes will be carried out on RNA isolated from blood. No adult fish will be sacrificed for these procedures. Fertilised eggs will be treated with Pseudomonas fluorescens culture to observe the embryos' tolerance to infection in vitro. Behaviour of fish can be observed in all phases of their development from hatched larvae to adulthood using different approaches (observation, video analysis, and movement recording implantats). Obtained data will be analysed using basic statistical tools. RELEVANCE: Wild fish and their offspring have to be based in hatchery at least for a short time in order to obtain stocking material. It is of great importance not to subject these fish to prolonged selection pressure that is different from selection in the wild. Results from this study could be used to identify individual fish that will have the highest survival rate after release and possibly to identify individual fish that are appropriate for fish farm environment and crossing with domesticated strain to improve its genetic diversity.
Significance for science
A simple and cheap method of fertilized fish eggs incubation until hatching was developed. Fish embryo model could be used to assess the impact of various chemicals, infectious agents or environmental conditions on fish survival rate. In the past year, correlation between survival rate after infection with P. fluorescens and genetic characteristics of parents.
Significance for the country
We did not produce results with applicative value, but as the project is based in university it was also used in educational purpose. A student of Biotechnology will use his part of results in a graduation thesis while another undergraduate student of Biotechnology gained practical laboratory experience trough voluntary work. Knowledge gained during the project was also used with other long running salmonid projects in the lab, they will also be used on other species.
Most important scientific results
Annual report
2011,
final report,
complete report on dLib.si
Most important socioeconomically and culturally relevant results
complete report on dLib.si
