Validation of feed efficiency selection methods

Offentlig prosjektsammendrag

Feed efficiency is among the most economically important traits in animal production. Improving feed efficiency will reduce the production costs and environmental footprint. However, feed efficiency is not necessarily the same trait over the entire life span of an animal. Early in life, Atlantic salmon has a high growth rate which explains a large part of the genetic variance in feed efficiency. Later in life, deposition efficiency through lipid metabolism is probably the most important determinant of feed efficiency. Hence, the feed efficiency complex is affected by several traits, including feed intake, growth, maintenance, and lipid deposition. Modern selective breeding methods uses information on individual phenotypes linked with individual genomic data. As the feed efficiency is the ratio between feed intake and body tissue growth, both traits should be recorded individually. While individual growth is easily recordable, individual feed intake in large-scale aquaculture systems is not. Indicator traits have therefore been used to indirectly assess feed intake and/or feed efficiency. However, the methods available today cannot be directly implemented in the breeding program of salmonids because the results are varied and based on limited data that lack statistical power to determine the effect of genetic selection. There is a need for validation experiments combining all methodologies available for indirect phenotyping of feed efficiency (feed intake at tank and/or individual level, fat measurements in whole body, fillet, and visceral fat, growth, and maintenance using stable isotope profiling) over the entire life span of families from the breeding nucleus. The knowledge gained will determine how feed efficiency can be implemented in the breeding scheme of salmonids.