Resistance against CMS and AGD. Vibeke Emilsen, Research scientist Aviemore 25. May 2016

Transcription

1 Resistance against CMS and AGD Vibeke Emilsen, Research scientist Aviemore 25. May 2016

2 The farmers have some challenges Many of those challenges can be solved through focused and knowledge based breeding! Advanced technology Selection methods Several traits

3 Mai Jun Jul Aug Sep Okt Nov Des Jan Feb Mar Apr Mai Jun Jul Aug Sep Okt Nov Des Individual weight (Kg) Average losses during sea phase 1 million smolts tons lost! % 5.3 % 4.3 % Biomass (tons) 2 HANDLING! Biomass Source: Mattilsynet

4 + AGD Sea lice

5 Mortality 14G for 8 locations Handling 3.9 mill NOK 5.4 mill NOK % Week number Source: Rendition of EWOS data by Jon Harald Pettersen

6 Losses due to handling and treatment Why do fish die? Stress Crowding Oxygen deficiency Injuries Diseases Loss Why do fish survive? Placement Free from diseases More robust against treatments More robust against handling

7 What defines good health in humans or a robust and healthy salmon? Foto: Marta Alarcon, NVI

8 Breeding for a more robust fish - Improved heart and gill health Increased resistance against CMS Increased resistance against AGD Foto: Marta Alarcon, NVI

9 Heart disease - CMS (Cardiomyopathy syndrome) Inflammation of the heart wall Pathological agent is piscine myocarditis virus (PMCV) Increased viral load in the heart gives increased tissue damage to the heart and CMS related mortality Often triggered by operational stress factors Affects large salmon ready for harvest

10 Increased resistance against CMS Atlantic salmon with genetic marker for CMS resistance will remove the virus and repair the damages Atlantic salmon without genetic marker for CMS resistance will get tissue damage and develop chronic inflammation of the heart Red color = inflammation Light color = scar tissue Scar tissue reduces the elasticity of the heart, reduces the hearts ability to pump blood which again increases the possibility of heart failure

11 Sum of histopathological score Improved heart health Gene markers for CMS resistance Reduce viral load in the heart Reduce tissue damage in the heart Significant differences in tissue damage between strong and weak group 0 qq One Qq copy of QQ CMS QTL No copies of CMS QTL Two copies of CMS QTL

12 Mortality (%) Mortality in offspring (%) QTL-validation field outbreak of CMS - year class 2011(large brood fish) Mortality family variation Mortality - genotypes 50% 18.00% 40% 16.00% 14.00% 25 % 30% 12.00% 10.00% 20% 8.00% 10% 6.00% 4.00% 2.00% 0% Families 0.00% No copies qq of One Qq copy of Two QQ copies of CMS h QTL CMS QTL CMS QTL Genotype CMS-QTL in father

13 Gill disease - Amoebic Gill Disease Challenge agent is the amoeba Paramoeba perurans Attaches to the gill surface Causes increased cell growth and adhesions of the gill lamellae Characteristic white mucus spots are visible on the gills Jannicke Wiik-Nielsen, Vetrinærinstituttet

14 The amoeba causes great damage to the gills Reduced gill function Adherence of the gill lamellae will increase mucus production and cause respiratory problems Disorder of the osmoregulation Varying extent of damage within the same gill surface O 2 uptake is maintained when the fish is kept calm Stress will aggravate gas exchange White = nucleus, Green = «defense mechanisms», Red = cloride cells Long lasting AGD infections will provide favorable conditions for the amoeba Reduced effect of freshwater and hydrogen peroxide Total gill damage with fatal outcome

15 High heritability for AGD resistance - Gill score Atlantic salmon generation 2014 Atlantic salmon generation 2015 Gill score, challenge trial Gill score, field outbreak

16 AGD mortality (%) High heritability for AGD resistance - Mortality In the first family tests with IPN the heritability was % 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Challenge trial with AGD Families Atlantic salmon generation 2014 Atlantic salmon generation 2015 Survival, challenge trial % reduced mortality in an AGD outbreak

17 Genome scan from AGD challenge trial No large clear single markers (QTLs) this applies to most traits high heritability is not the same as major QTLs Next step is genomic selection Involves the sum of all QTLs

18 Bath interval (days) Average Gill Index The effect of traditional breeding Phenotypic AGD trend in Marine Sib-test group bath interval av index Year Class 0.00

19 Takk for oppmerksomheten