Aquaculture and Reproductive Biology

Igor Babiak (PhD, professor), Oddvar Ottesen (PhD, senior researcher), Sylvie Bolla (PhD, senior researcher), Kiron Viswanath (PhD, professor), Birgitta Norberg (PhD, professor II), Brendan McAndrew (PhD, professor II), technical staff, PhD and MSc students.

The research areas include various aspects related to farming and sustainable development of aquaculture of finfish species that are of importance to the county, state, and international communities: reproductive biology; reproductive biotechnology; broodstock management; embryogenesis; and larviculture. Currently, several national and international research projects are ongoing and the further research projects are pending or in preparatory phase.

Biology and preservation of gametes

To learn more about basic biological features related to gamete quality, which is an important issue in aquaculture, we apply a continuous investigation throughout the reproductive season of Atlantic halibut and we also conduct research in other species, as Atlantic cod, plaice or turbot. The research include: monitoring of changes in semen parameters through quantitative assessments as: spermatozoa concentration, osmolality, or pH. Spermatozoa motility parameters are estimated using Computer-Assisted Sperm Analysis (CASA) system. We study spermatozoa ultrastructure using electron scanning and transmission microscopy. We monitor fertilization ability of spermatozoa and oocytes throughout the season in Atlantic halibut broodstock. We apply useful biotechniques, as chilled storage of gametes or cryopreservation of semen, to the hatchery routine. The PhD research project is to be started this year, including biochemistry and physiology (chemical composition, key metabolic enzyme activity, metabolism, lipid profile, or membrane integrity) of Atlantic halibut gametes. Two ongoing MSc projects are on cryopreservation of sperm of Atlantic halibut and Atlantic cod. This year we will establish and run an international sperm bank for farmed Atlantic cod as a part of R&D project on sustainable development of Atlantic cod farming, financed from Northern Periphery Programme, 2005-2007. Research institutions and cod farming industry from Norway, Scotland and Iceland are involved.

Larviculture

Quality of larvae is a key issue in marine aquaculture. We conduct various research related to larval quality in Atlantic halibut and Atlantic cod. In international project “Sustainable development of cod farming”, financed from the Northern Periphery Programme in 2005-2007, we conduct broad research on cod larval development (morphological, histological, biochemical) in order to learn about the causes of developmental malformations to the larvae. Several other research projects are pending or in preparation, addressing the use of probioticts for yolk-sac larvae incubation in halibut, swim bladder inflation in cod larvae, or the efficient production systems in cod.

Broodstock management

We are in possession of broodstock of Atlantic halibut kept under two photoperiod regimes. This broodstock is one of the oldest in Norway, established in 80’s. A National Breeding Station for Atlantic Halibut is located at our research facility. Also we possess two photomanipulated broodstocks of Atlantic cod. We are interested in various aspects of broodstock management, including nutrition and feeding that affects gamete quality.

Reproductive biotechnology

We focus on biotechnologies that are of direct use to the aquaculture industry to enhance its further development. They include: control of sex; control of maturation; and sterility.

In the project “Control of sex in Atlantic halibut: Towards production of monosex all-female stocks”, financed from the Research Council of Norway, 2005-07, we undertake a multidisciplinary research on mechanisms and control of sex determination and differentiation in halibut in order to develop the strategy to produce monosex all-female stocks. The project involves several research groups with relevant expertise in the different research areas. We search for sex-specific DNA sequences and conduct thorough cytogenetics research to better understand sex determination. We induce gynogenetic development to verify female homogamety and to obtain genetically all-female progeny. We undertake extensive research on altering phenotypic sex (sex reversal) in order to produce masculinized females (neo-males). The cell- and molecular-level effects of various agents on endocrine sex control are to be investigated. Different strategies to produce all-female stocks will be examined. It is anticipated that the project will result in (i) substantial knowledge of genetic and endocrine sex control mechanisms in Atlantic halibut, (ii) development of efficient protocols to produce all-female halibut, and (iii) establishing neo-male broodstocks and mass production of all-female juveniles.

In the project “Sustainable development of cod farming”, Northern Periphery Programme, 2005-2007, we study control of sex in Atlantic cod. Induced triploid development, non-hormonal sex reversal and induced gynogenetic development are the issue to be investigated.

Developmental biology and experimental embryology

One of the most interesting issues related to developmental biology in farmed fish species is the origin and fate of primordial germ cells (PGC), which are stem cells for further gametes. The knowledge of PGC may provide a powerful tool for control of maturation, fertility and sterility in farmed fish, which is a key problem to the aquaculture industry. In the project "Incubation, Cryopreservation, and Transplantation of Fish Blastoderm and Isolated Embryonic Cells: A New Technology for Efficient Germ-Line Transmission of Donor Genome"”, financed by the Polish State Committee for Scientific Research, 2003-2006, we work on a technology for deriving, in vitro safeguarding and in vivo transferring the entire genetic information contained in the undifferentiated embryonic cells in salmonids. The research include: isolation and incubation of embryonic cells and blastoderm fragments; cryopreservation of embryonic cells and blastoderm fragments; transplantation of blastoderm into recipient egg with partially or entirely removed blastoderm; transplantation of cryopreserved blastomeres and blastoderm fragments; and interspecies blastoderm transplantations. The plan for further research is to establish a platform for embryonic stem cell technology in Atlantic salmon via studies of PGCs and cell transplantation. PGCs provide a feasible alternative to embryos or eggs for the cryopreservation genetic resources in fish carrying commercially valuable traits. They can also be used for cell-mediated gene transfer and to study the molecular biology of germline specification. We will conduct molecular cloning and expression of PGC-specific genes in Atlantic salmon, including vasa , nanos-1 and dead end. Then, we will identify primordial germ cells (PGC) and determine their migration patterns during ontogeny. We will produce viable chimeras to demonstrate the technology of transplanting undifferentiated blastomeres, PGCs, and blastoderm fragments. Also, the development of relevant cell culture methodology for pluripotent stem cell lines in farmed species will be a priority in the future research.