Sea-bass and sea-bream aquaculture Estimates of potential gains from improvements in genetic strains

1. Universidade do Algarve Faculdade Ciências do Mar e do Ambiente Genetics and Selection 2007/2008 Sea-bass and sea-bream aquaculture Estimates of potential gains from improvements in genetic strains www.webdelanzarote.com www.agrino.org Alexandre, Daniel nº 27868

2. Genetics and Selection 2007/2008 Index An overview of sea-bass and sea-bream aquaculture Why we need the Techniques of Molecular Biology Examples of Genectics Studies

3. An overview - Why Genetics and Selection 2007/2008 Why Sea-bass and sea-bream aquaculture • Elevated economic value • Decrease natural stocks • Controlled reproduction techniques • High adaptability to intensive rearing conditions Fig. 1:Manual on Hatchery Production of Sea-bass and Gilthead Sea-bream Opened the door towards the industrialization of marine aquaculture

4. An overview - History Genetics and Selection 2007/2008 Before 80`s • Collection of wild juveniles from the sea • Extensive culture systems 80`s Fig. 2: Evolution of sea bass and sea bream production in the Mediteranean(1986- 1990)in www.fao.org • Beginning large scale production in Spain, Italy and Greece Nowadays • Major species produced in the mediterranean aquaculture industry • Annual production of about 100,000mtn Fig. 2: Evolution of sea bass and sea bream production in the Mediteraneanin www.fao.org

5. Why we need the Techniques of Molecular Biology Genetics and Selection 2007/2008 • The decline of ocean fisheries stocks has provided a rapid growth in fish farming • Modern Technologies • Improved the production and quality • Reduced the environmental impact (public perception) Increasing pressure in the field of aquaculture

6. Why we need the Techniques of Molecular Biology Genetics and Selection 2007/2008 Necessity to adopt the most recent techniques of Molecular Biology • Can offer precise information on the actual genes responsible for: • Growth • Disease resistance • Flesh quality • Health conditions • Welfare Molecular Techniques will find their place in the management of fish farmig

7. Examples of Genectics Studies (1) Genetics and Selection 2007/2008 Inflate Swimbladder • Swimbladder of fishes is a hydrostatic, buoyancy-regulating organ; • Correct swimbladder inflation is essential for functional buoyancy control; • The swimbladder has been regarded as a major obstacle in the rearing of important commercial species; Uninflated or hypertrophic swimbladders are generally regarded to result from the application of unsuitable culture conditions BUT…

8. Examples of Genectics Studies (1) Genetics and Selection 2007/2008 Peruzzi et al, 2007 • In this work, 24full-sibling families from a 4 dams × 6 sires factorial crossing were reared under communal conditions • Imbalance in family size • Different survival rates for larvae with normal and abnormal inflation of the swimbladder • The results suggest that paternally and maternally inherited factors may contribute to the expression of swimbladder anomalies Fig. 3: Photomicrographs of 20 dph (7–8 mm TL) sea bass larvae with (a) normal functional swimbladder, (b) hyper-inflated swimbladder, and (c) non-inflated swimbladder. Are hypothesis of some level of genetic influence associated with these defects

9. Examples of Genectics Studies (2) Genetics and Selection 2007/2008 Saillant et al, 2003 Sex ratios • The females grow faster than males in farmed populations • Much interest has been generated concerning the development of monosex female populations • Environmental sex determination (ESD) has been described in an increasing number of fish species In this Work: Tested the effects of rearing density and parental factors on sex ratios Significant parental influences on sex ratio

10. Examples of Genectics Studies (3) Genetics and Selection 2007/2008 There is increasing interest in the welfare of intensively farmed fish Protecting the welfare of farmed animals is a central requirement of any animal rearing system • The development of appropriate environmentally related husbandry practices can minimize the stress on farmed fish • To assess the effects of environmental stress conditions on fish, the examination of a suite of biomarkers, including endocrine parameters, has been suggested

11. Examples of Genectics Studies (3) Genetics and Selection 2007/2008 Terova et al, 2005 Quantification of a glucocorticoid receptor • Glucocorticoids (cortisol and Corticosterone) are known to mediate stress response • They bind to a high-affinity glucocorticoid receptor (GR) • which acts as ligand-dependent transcription factor to control and regulate gene expression • Responsible for hyperglycemia

12. Examples of Genectics Studies (3) Genetics and Selection 2007/2008 Terova et al, 2005 • Quantification of a glucocorticoid receptor on • 4 diferentes rearing densitys • On this work has determined the sequence of the mRNA coding for GR Fig. 5: Glucocorticoid receptor expression levels measured by real-time PCR in Dicentrarchus labrax reared at 10, 50, 80 and 100 kg/m3. Cytoskeletal actin has been used as endogenous control. The means of three animals in each group are shown. Bars indicate standard error of the mean. Differences were determined by unpaired Student’s t-test. Differences between letters indicate significantly different means ( P <0.05). Clearly demonstrated that chronic stress affects GR expression

13. Examples of Genectics Studies (4) Genetics and Selection 2007/2008 The acquisition of a stock should be considered the single most important aspect of broodstock management • The genetic size of the acquired population will have the greatest effect on the probability of success in the fish culture Inbreeding Production phenotypes to decrease significantly The truth is that genetics requires sophistication, extra facilities and adds additional financial burdens

14. N=30 N=661 N=30 N=30 Examples of Genectics Studies (4) Genetics and Selection 2007/2008 Borrell et al, 2007 • Use of microsatellitesand a combinatorial optimization approach • in the acquisition of broodstocks for hatcheries • Could be used for retrospective parental assignments • and comparisons of viability of offspring with different parental origins

15. The one principal objective can be: Findthe “genetic model” for aquaculture Final Considerations Genetics and Selection 2007/2008 Genetic studies guive extra information about species Can be use on aquaculture

16. References Genetics and Selection 2007/2008 • Moretti A, Fernandez-Criado M, Cittolin G, Guidastri R, 1999. Manual on Hatchery Production of Sea-bass and Gilthead Seabream. Food and Agriculture Organization of the United Nations, Rome. • Mylonas C, Cardinaletti G, Sigelakia I, Polzonetti-Magni A, 2005. Comparative efficacy of clove oil and 2-phenoxyethanol as anesthetics in the aquaculture of European sea bass (Dicentrarchus labrax) and gilthead sea bream (Sparus aurata) at different temperatures. Aquaculture, 246: 467– 481. • Peruzzi S, Westgaard J, Charain B, 2007. Genetic investigation of swimbladder inflation anomalies in the European sea bass, Dicentrarchus labrax L. Aquaculture, 265: 102–108. • Saillant E, Fostier A, Haffray P, Menu B, Laureau S, Thimonier J, Chatain B, 2003. Effects of rearing density, size grading and parental factors on sex ratios of the sea bass (Dicentrarchus labrax L.) in intensive aquaculture. Aquaculture 221: 183–206. • Terova G, Gornati R, Rimoldi S, Bernardini G, Saroglia M, 2005. Quantification of a glucocorticoid receptor in sea bass (Dicentrarchus labrax, L.) reared at high stocking density. Gene 357: 144 – 151. • Chini V, Rimoldi S, Terova G, Saroglia M, Rossi F, Bernardini G, Gornati R, 2006. EST-based identification of genes expressed in the liver of adult seabass (Dicentrarchus labrax, L.). Gene 376: 102–106. • Borrell Y, Carleos C, Asturiano J, Bernardo D, Vázquez E, Corral N, Sánchez J, Blanco G, 2007. Use of microsatellites and a combinatorial optimization approach in the acquisition of gilthead seabream (Sparus aurata L.) broodstocks for hatcheries. Aquaculture 269: 200–210.