Fiskeavl nye verktøy gir nye muligheter Akvakulturseminar i Vitenparken, 17. des. 2015 Hans Magnus Gjøen Institutt for husdyr og akvakulturvitenskap
Eksempler på nye verktøy og nye muligheter.. Genomisk seleksjon (GS) i avlsprogram for fisk Bruk av «optimal contribution» i fisk Utnyttelse av ikke-additive effekter Seleksjon direkte på domestisering
GS konsekvenser for fiskeavlen Hovedeffekt: Mulighet for seleksjon mellom fullsøsken uten egen phenotype Effektiviserer seleksjonen på viktige egenskaper med minst 50 %: Sykdomsresistens / overlevelse Kvalitet Stress Fôrutnyttelse
Eksempel på resultat med bruk av optimal contribution og DNA-teknologi 1,2 G 1 0,8 0,6 0,4 0,2 h 2 =0.5 CS OCA OCF OCI 0 0 50 100 150 200 250 Familier Gjennomsnittlig genetisk fremgang pr generasjon for ulikt antall familier, n fam (n o =50, h 2 =0.5; F=0.005). Norwegian University of Life Sciences 4
Types of designs that are used in fish breeding Sires Sires Dams Dams Nested/hierarchical design Partly factorial More partly factorial
Utnyttelse av ikke-additive effekter
Benefits Utilisation of heterosis ca 50% of all genetic variation Homogenous offspring from crosses Less variation at harvest Protection of genetics Half of heterosis is lost in F2
Beskyttelse vha. F2 - Breakdown F1 Aa X Aa F2 AA Aa Aa aa 25% 50% 25%
Example from salmon: 38 % better than the avg. of pure
Crossbreeding in fish Not used in fish today Selective breeding in fish species for just a few generations different high performing lines have not been available Why now? New DNA technology will make the development of such lines faster and easier. high density SNP chips identify the chromosome segments responsible for heterosis lines yielding substantial amount of heterosis can be generated
Ways of utilising heterosis in fish: A modified scheme for Reciprocal Recurrent Selection (RRS) Line 1 Selection: Both pure and cross-breed performance Linje 2 Selection: Both pure and cross-breed performance Selection Selection Line 1 Pure breed offspring Line 2 Pure breed offspring
Ways of utilising heterosis in fish: A modified scheme for Reciprocal Recurrent Selection (RRS) Line 1 Selection: Both pure and cross-breed performance Breeding value estimation Linje 2 Selection: Both pure and cross-breed performance Selection Selection Sire i 1 x Dam j 2 Sire j 2 x Dam i 1 Line 1 Pure breed offspring Line 2 Pure breed offspring
Utvikling av nye linjer Time / generations NUCLEUS broad and long term breeding goal Line A Hybrid v1.0 Hybrid v2.0 Line B Growth, trait 1, 2, n Hybrid v3.0
Utvikling av nye linjer Time / generations N U C L E U S Line A Hybrid v4.0 Hybrid v5.0 Line B Hybrid v6.0
Seleksjon direkte på domestisering Er det mulig å selektere effektivt både for produksjon og velferd/lavt stress? Selektert Lavstress Tilvekst
Selection response for high- and low- cortisol levels (Pottinger & Carrick, 1999)
Effects of selection on welfare/fitness or reduced stress on other traits Growth ( ) In rainbow trout, LR grows faster than HR, when reared in co-culture. LR fish tends to be dominant. (Pottinger, 2006) Feed utilization E.g. rainbow trout (Øverli et.al. 2006) Disease resistance E.g. in channel catfish (Small & Bilodeau, 2002) Stress led to alteration and mucus peeling off in rainbow trout gastrointestinal tract. This changing might lead to increase susceptibility to bacteria infection (Olsen, et al. 2005). Reproduction Rainbow trout, ovulation (Contreras-Sanchez et al., 1998) Effect of cortisol (Pankhurst and Van Der Kraak, 2000)
Production consequences: Growth and feed utilization is improved in stress resistant fish Growth (% / day) 3 2 1 * Feed factor 0.75 0.50 0.25 * 0 0 LR HR LR HR Øverli, Ø., Sørensen, C., Kiessling, A., Pottinger, T.G., and Gjøen, H.M. (2006) Selection for improved stress tolerance in rainbow trout (Oncorhynchus mykiss) leads to reduced feed waste. Aquaculture, 261: 776-781 (1.374, 0)
Differences in Juveniles and adults from rainbow trout lines, selected for (HR) or low (LR) stress response EXP 2 Latency to first movement (s) 500 400 300 200 100 0 A AB AB AB C D 100% 35% 10% LR HR Oxygen saturation Latency to first movement in rainbow trout larvae exposed to water with 100, 35 and 10 % oxygen saturation at xxx day degrees after hatching. The larvae originated from parents selected for high (HR) or low (LR) stress responsiveness. Different letters indicates significant differences (P<0.05). (Höglund, Gjøen & Øverli, 2007)
HR- and LR-lines - also display different behavioural characteristics Groups of HR and LR fish were exposed to a paired conditioned stimulus (CS; water off) and unconditioned stimulus (US; confinement stressor). Exposure to 18 CS US pairings, a conditioned response (CR) manifested as an elevation of blood cortisol levels on presentation of the CS only. The extinction of the CR in the two lines was compared. The decline in mean plasma cortisol levels after exposure to the CS over successive tests suggested that the CR was retained for a shorter period among the HR (<14 days) than LR fish (<21 days). Plasma cortisol levels (stress response) when exposed to the CS was significantly greater among the LR than HR fish at 14 and 21 days These results suggest that there are differences in cognitive function between the two lines. (Moreira et.al., 2004)
Experiment set up Sorting by time to emerge Thesis presentation
Oksygenforbruk i tidlig og sent klekkede familier 300 ** 250 VO2 (mgo2/kg/h) 200 150 100 50 Early hatch late hatch 0
Growth and swim-up SGR (%g/day) 4 *** 3,5 3 early swim up late swim up 2,5 2
Growth and swim-up Maximum growth after 2 weeks in isolation 2,5 ** 2 SGR (% g/day) 1,5 1 Early swim-up Late swim-up 0,5 0
Behavior and swim-up Sum of feeding scores after 5 days 8 7 * Early swim-up Late swim-up 6 Feeding score 5 4 3 2 1 0
Sammenhenger mellom stress og klekke/oppsvømmingstidspunkt - Konklusjoner Part 1: Klekketidspunkt Tidlige familier: Lavere metabolsk rate Lavere oksygenforbruk Oppsvømmingstidspunkt Tidlig Bedre tilvekst Tidlig Modige Disse, sammen med andre resultater, indikerer at vi kan finne individer som er modige, men ikke aggressive
Testing aggressive / submissive behaviour in tilapia Time and amount of feed - after stressor Large and small fish together stress (Pham, 2007)
Konklusjon det er behov for FoU innenfor flere ulike avlsteoretiske områder for å dra full nytte av nye verktøy, bl.a. innen: Genomisk seleksjon (GS) i avlsprogram for fisk Bruk av «optimal contribution» i fisk Utnyttelse av ikke-additive effekter Seleksjon direkte på domestisering