Feed efficiency is a key fish trait in sustainable aquaculture. Improving the amount of edible product produced relative to the feed provided to fish (i.e. feed efficiency) offers considerable potential to improve both profitability and environmental sustainability of aquaculture.
For example, feed plays a crucial role in the economic and environmental performance of Atlantic salmon production with the cost of feed accounting for over 50% of the total production cost and 73-80% of the carbon footprint.
The decades-long breeding programmes for rainbow trout demonstrate that feed efficiency has been improved significantly, and that the improvement is also visible at commercial fish farms. The two studies presented show up to 18-19% improvement in feed efficiency after 8-10 generations (Vandeputte et al.; Kause et al.). This genetic improvement has been obtained by selecting for traits that are genetically correlated with feed efficiency, such as body composition and growth rate.
Genetic improvement of feed efficiency could be further improved if feed intake (and hence feed efficiency) could be recorded on individual fishes or on families. One option is to record feed intake in replicated family-tanks. This option was studied by Difford et al. in Atlantic salmon. The work on methods to improve feed efficiency by selective breeding continues as a co-operation between NewTechAqua and AquaIMPACT.
In breeding programmes of rainbow trout and Atlantic salmon, pre-determined sire and dam mating can be performed to produce families, while group mating is common in gilthead seabream and European seabass. In group mating, it is more challenging to control which sires and dams produce offspring and how many offspring they will have, which needs to be account for in breeding programmes. Rates of genetic improvement and inbreeding were evaluated in a) controlled family mating and b) group mating schemes using a computer simulation. The simulation model by Roozeboom et al. is flexible and can be used for many other purposes also.
Presentations and e-posters presented in AE2020 related to this topic – see below
EVALUATION OF GENETIC GAIN IN RAINBOW TROUT FED STANDARD OR “FUTURE” DIET AFTER 10 GENERATIONS OF MULTI-TRAIT SELECTION IN THE AQUALANDE SELECTIVE BREEDING PROGRAM.
M. Vandeputte, G. Corraze, J. Doerflinger, F. Enez, F. Clota, F. Terrier, M. Horat, L. Larroquet, N. Dechamp, V. Petit, P. Haffray, S. Skiba-Cassy & M. Dupont-Nivet
These results show important effects of selective breeding on productivity, including correlated response on feed conversion ratio (FCR: -19%). Although FCR results for the future feed remain questionable, growth was very satisfactory, showing the potential of total replacement of fish meal and fish oil, provided long-chain n-3 PUFA- fatty acids are provided in sufficient quantity (here by the micro-algal biomass).
ROLE OF SELECTIVE BREEDING IN THE IMPROVEMENT OF FEED EFFICIENCY AT RAINBOW TROUT FARMS
A. Kause, A. Nousiainen & H. Koskinen.
‘These improvements in resource efficiency are a win-win for both industry and environment – the same amount of sea food can be produced with significantly reduced amounts of raw materials and reduced environmental impact.’
FAMILY DIFFERENCES IN FEED INTAKE AND FEED COVERSION RATIO OF ATLANTIC SALMON
G. F. Difford, B. Hatlen, B. Gjerde, J.P. Wold, A.T. Norris & A.K. Sonesson
Our objectives are to use family-based tank feeding to quantify the family differences in feed intake, growth, lipid deposition in Atlantic salmon. There is considerable and significant between family variation in all traits within the feed efficiency complex demonstrating that there is genetic potential between families which can be exploited to genetically improve feed efficiency.
COMPARING SELECTION RESPONSE AND INBREEDING LEVEL IN FAMILY AND GROUP MATING DESIGNS OF SEA BREAM AND SEA BASS
C. Roozeboom, H. Komen & J.W.M. Bastiaansen
Comparing breeding program designs that depend on a large number of genetic, reproductive and other biological constraints is now possible with the developed stochastic simulation software. In the current study, the family design gives a higher rate of genetic improvement but also leads to a higher rate of inbreeding.