Selective breeding in fish and conservation of genetic resources for aquaculture

Selective breeding in fish and conservation ofgenetic resources for aquacultureCurtis E Lind, RW Ponzoni, NH Nguyen, and HL KhawThe WorldFish Center ICAR 2012, Vancouver 31st July

IntroductionDifferences between livestock and fishSelective breeding approaches in fishGenetic resources for aquacultureConcluding remarks

aquaculture provides nearly half of all food fish

mostly freshwater species farmed in Asia

key constraints are lack of feed, seed and capacity

<10% is from genetically improved strains

fish breeding and genetic resources major issues

livestock vs. fish

High 100 – 10,000 progeny per female per cyclereproductive rate Low < 10 progeny per female per cycle

1-3 yearsgeneration interval 3-8 years

few defined breeds no breed societiesdomestication many defined breeds preserved by keepers or breed societies

often wild-caught producer or hatchery ownedsource of breeders stud farms producer-owned domesticated stock

greater selection intensity, response per generationlivestock vs. fish greater annual genetic gain risk of inbreeding greater

greater potential for rapid dissemination at scalelivestock vs. fish focus on developing and maintaining strains focus on minimizing impact to wild genetic resources

Selective breeding in fish

Several approaches to geneticimprovement feasible with fish hybridization transgenesis cross-breeding chromosome manipulation selective breeding only approach where gains are cumulative and permanent

Several approaches to geneticimprovement feasible with fish hybridization transgenesis cross-breeding chromosome manipulation selective breeding multiple selection approaches with varying complexity

Several approaches to geneticimprovement feasible with fish “combined” selection within-family selection cohort selection individual (mass) selection selective breeding multiple selection approaches with varying complexity

Application in fish lags farbehind livestock or crops “combined” selection within-family selection cohort selection individual (mass) selection selective breeding multiple selection approaches with varying complexity

age unknownpedigree and geneticrelationships unknown individuals selectedhigh risk of on phenotype onlyinbreeding (measurable alive) μ 150 g 300 g 550 gIndividual selection

limited success in fish due to high inbreeding rates can be managed with controlled mating and standardized family contributions challenging in developing countriesIndividual selection

selection done within inbreeding limited bycohort or group mating between cohorts (fe)males rotate field personnel comfortable with this designCohort selection

requires family identification families reared in separate tanks, hapas, cages high within-family selection intensity possible inbreeding easily controlled by rotational matingWithin-family selection

successfully applied FaST strain at Central Luzon in tilapia State University, Philippines genetic gain for body weight estimated at 12% per generation after 12 generations easily managed but requires greater inputsWithin-family selection

utilizes information from can produce single indexindividual plus relatives, incorporating multiple traits linked by pedigree uses Best Linear Unbiased Prediction (BLUP) to estimate breeding values (EBVs)BLUP accounts for systematic effects (e.g. sex, batch, age) and maternal, common environmental effectsCombined selection

BLUP permits selectionof traits unmeasured on information from relatives candidates related individuals likely have similar EBVs inbreeding can be an issue if unchecked successfully applied in salmon, tilapia, Indian carpsCombined selection

ample evidence that constraints are usually selective breeding can be financial and lack of successful in fish adequate capacity current breeding programs mostly focus on growth improvements unfavourable correlated traits must be monitoredBreeding programs in fish

conservationof fish genetic resources

genetic resources:fish genetic genetic material of actual or potential value (Convention on Biological Diversity) resources genetic resources for food “fish” often extended to and agriculture derived from include other aquatic fish species organisms

biological diversity often categorized infish genetic hierarchical levels resources intra-specific genetic diversity

biological diversity often categorized infish genetic hierarchical levels resources intra-specific genetic diversity species diversity

biological diversity often categorized infish genetic hierarchical levels resources intra-specific genetic diversity species diversity ecosystem diversity

biological diversity often categorized infish genetic hierarchical levels resources intra-specific genetic diversity (population diversity) species diversity ecosystem diversity

intra-specific concerned with management of genetic and resource at population level population level maintenance of gene variants (alleles) many alleles will characterize a population

intra-specific problem is... genetic and fish vulnerable to rapid loss of diversity population level difficult to maintain pedigree high reproductive rate large populations from a few breeders exaggerated genetic drift low effective population size (Ne)molecular tools provide some assistance

intra-specific problem is... genetic and fish vulnerable to rapid loss of diversity population level can be managed through proper hatchery practices and training …and developed a production level industry structure diversity not critical if maintained in nucleus generally not present

species and consider consequences of interactions among species or populationsecosystem levelfish are cultured in manyenvironments and systems

species and consider consequences of interactions among species or populationsecosystem level fish can readily escape

species and consider consequences of interactions among species or populationsecosystem level fish can readily escape and are difficult to recapturemanaging impacts ofescapees is a major concern wild genetic resources

species and consider consequences of interactions among species or populationsecosystem level non-natives can proliferatemanaging impacts ofescapees is a major concern wild genetic resources

species and consider consequences of interactions among species or populationsecosystem level fish can hybridize easily or breed with wild relativesmanaging impacts ofescapees is a major concern wild genetic resources

issues at this level are farspecies and more complexecosystem level difficult to predict likely impacts often must incorporate broader environmental management strong governance, regulation and science required

scope for substantial gains throughselective breeding programs in fish essential for future aquaculture development concluding remarks ample proof of success significant progress canoccur with limited inputs if properly trained

genetic improvement should notcome at the cost of conservation vice versa genetic management concluding remarks necessary for both government support important for both

photo credits:1. Flickr/ Dr DeNo full manuscript:7-11. Flickr/ PraYudi Lind, CE, Ponzoni, RW, Nguyen, NH and Khaw, HL. (2012), Selective12-18. top: Flickr/ Robin Robokow breeding in fish and conservation of genetic resources for aquaculture. bottom: Flickr/ ILRI Reproduction in Domestic Animals, 47 (Suppl.4): 255–263.19. Flickr/Johnny Peacock doi: 10.1111/j.1439-0531.2012.02084.x20-23. Flickr/ Guy Mason25. Curtis Lind26. Flickr/ wockerjabby thanks to:27. top, middle: Curtis Lind ICAR 2012 organizers, chair and hosts bottom: Flickr/Marcodvz28. Flickr/ Seafdec30. mymakolet.com31. anonymous/CEL collection32. Flickr/ ~ Martin ~34. Wikipedia36. Flickr/ Michael McCullough37. Flickr/ Mike_tn38.39.41. Flickr/ Suneko Flickr/ US Fish & Wildlife Service Flickr/ linuts acknowledgements42. anonymous43. Flickr/ Ray Morris 144. Illinois Natural History Museum45. www.elusivetrout.com46. Flickr/ Patrick Choi47-48. Peter Fredenburg49. Bill Reidtilapia illustrations:Susanne Weitemeyer,Scandinavian Fishing Year Book

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Selective breeding in fish and conservation of genetic resources for aquaculture

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Selective breeding in fish and conservation of genetic resources for aquaculture Presentation Transcript