The Green Deal has high priority on increasing farm animal welfare and in reducing the use of antibiotics in food production. Selective breeding, genomic tools, novel feeds, and intelligent feeding control can all contribute to these goals.
Selective breeding programmes have the potential to produce robust genotypes that can manage multiple environmental disturbances and stressors. Such factors include diseases and variable abiotic and biotic stressors e.g. induced by climate change.
Aquaculture should mitigate the impacts of climate change on the operations as well as to reduce carbon footprint and to search for new growth opportunities. Dagnachew et al. working on Atlantic salmon show that there are genotypes that are superior across a variety of environments with different water temperature profiles.
Genomic selection is especially useful to genetically improve fish traits such as disease resistance. Fraslin et al. show that genomic selection can be used to improve resistance against Columnaris disease in rainbow trout. This is an emerging disease, caused by Flavobacterium columnare, that is affecting rainbow trout farming worldwide.
In genomic selection, thousands of DNA markers are used to predict the genetic potential of individuals (i.e. breeding value) to transmit the preferred traits to their offspring. Genomic selection is the current industry standard in cattle, pig, chicken and Atlantic salmon breeding. Genomic selection allows one to predict the breeding value from a tissue sample alone, and it increases the accuracy of breeding values, and aids to include novel fish traits (e.g. disease resistance, product quality) into breeding programmes.
For more on the industry applications of genomic selection, see the AquaIMPACT Newsletter 1/2019: https://uutiskirje.luke.fi/archive/show/3308970
Fish performance is not influenced only by fish’s own characteristics, but also by its gut microbiota. This can be researched using genome-based identification methods, and Piazzon et al. demonstrated that gilthead seabream selected for fast growth have a unique microbiota that deviates from their slower growing counterparts. This leads to a better adaptation to changes in diet composition, and there is now an increasing interest in controlling bacterial populations in gut to improve animal welfare in a changing environment.
Intelligent feeding control in response to monitored changes in fish behaviour and growth status has gained increasing attention. Georgopoulou et al. presented advances in automated tracking of fish movement and feeding behavior that can be used to increase fish welfare and to optimize feeding, and that are useful e.g. in monitoring fish in new production environments such as recirculating aquaculture systems (RAS).
Presentations and e-posters presented in AE2020 related to this topic – see below
GENETIC VARIATION FOR CLIMATE CHANGE RESILIENCE IN GROWTH OF ATLANTIC SALMON
B.S. Dagnachew, I. Thorland, B. Hillestad & A. Kettunen
The results showed there is limited genotype re-ranking for growth in Atlantic salmon, which indicates that either there exits limited genetic variation in climate change resilience, or the current breeding population is robust towards climate change.’
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GENOMIC BASIS OF RESISTANCE TO Flavobacterium columnare IN RAINBOW TROUT
C. Fraslin, A. Nousiainen, H. Koskinen, R.D. Houston & A. Kause
Disease resistance is a suitable target trait for genetic improvement by selective breeding, and genomic selection is a useful approach to speed up this process.
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GENETIC SELECTION FOR GROWTH DRIVES DIFFERENCES IN INTESTINAL MICROBIOTA COMPOSITION AND PARASITE DISEASE RESISTANCE IN GILTHEAD SEA BREAM
M.C. Piazzon, F. Naya-Català, E. Perera, O. Palenzuela, A. Sitjà-Bobadilla & J. Pérez-Sánchez
The genetic background, microbiota composition, and physiological plasticity are intricately linked, yielding selection for fast heritable growth leads to more robust individuals. They adapt better to dietary changes, reshape their intestines and organosomatic indexes for an efficient nutrient digestion and absorption, and cope more efficiently with intestinal pathogens.
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TRACKING AND ANALYSIS OF THE MOVEMENT BEHAVIOUR OF EUROPEAN SEABASS Dicentrarchus larbax IN RECIRCULATING AQUACULTURE SYSTEMS (RAS)
D. G. Georgopoulou, O. Stavrakidis-Zachou, N. Mitrizakis, V. Chalkiadakis & N. Papandroulakis
We developed an automated routine that enables us to extract fish trajectories (of short time length) in RAS systems and we present its prediction accuracy and its potential use.