Title: Development of a Health Genomic Profile
for the captive Atlantic bluefin tuna (Thunnus thynnus)
Coordinator: Ivona Mladineo
- Institute of Oceanography & Fisheries (IOR), Šetalište Ivana Meštrovića 63, 21000 Split, Croatia
- Hopkins Marine Station, Stanford University, 120 Oceanview Blvd, CA 93950, USA
Funds: 50.000,00 EUR UKF financing
17.000,00 EUR Kali tuna d.o.o., IOR, HMS cofinancing
The expansion of bluefin tuna production through aquaculture largely depends upon our ability to maintain captive populations of bluefin tunas for rearing, reproduction and fingerling grow out. To improve the capacity to keep bluefin, reduction of the health risks and environmental influences will have to be defined. Molecular tools for characterizing the captive population health status and its physiology as the response to abiotic factors must be established in the captive environment, bur prior to that we need to detect and quantify appropriate parameters, indicative of fish response. The overall aim of UKF project was to construct a preliminary Atlantic bluefin tuna-specific genechip with only a handful of indicative genes (related to stress, health and immunity) that would be helpful in wide monitoring of tuna health status in rearing conditions. Our target genes were two proinflamatory cytokines: interleukin-1β (IL-1β) and tumor necrosis factor α (TNFα); other innate immunity genes: toll-like receptor 2 (TLR2), proteasome (Prot), lysozyme G type (Lys); stress-related genes: heat shock protein 70 (Hsp70), cytochrome 450 (Cyp), glucocorticoid receptor (GR) and metallothionein (MT); metabolism-related genes: hypoxia inducible factor (HIF), Na/K ATP-ase, uncoupling protein 1 and 3 (UCP1 and 3); and two housekeeping genes β-actin and 18ssu rDNA). In order to understand physiology of reared tuna in respect to rearing stress, we sampled during three main rearing events: the first when juvenile tuna were transferred from wild in rearing cages; the second when the same tuna population was kept for one year in the rearing environment; and the third when tuna were harvested after been kept 1.5 years in cages. Results confirmed that the most stressful period for the fish was their transfer into cages while rearing and harvest did not significantly alter target gene expressions.
- Submission of target gene sequences to GeneBank aided to the availability of relatively scarce data on fish immunity sequences to broad number of comparative immunologists and phylogeneticists.
- A “chart” of levels of expression of target genes inferred by small-scale tuna-specific genechip, evaluated through three-years rearing period that will serve as an indicator of health level both for farmers and veterinarians.
- Industry co-financing that secured applicability of the project in Croatia and helped to define objectives of the follow-up research in frame of international collaboration.