Anna Kristina Sonesson, Gareth Frank Difford, Ashie Norris, Bjarne Hatlen
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引用次数: 0
Abstract
Background: There are both economic and environmental motivations to improve feed efficiency. However, direct genetic improvement of feed efficiency ratio (FER; weight gain/feed intake) is difficult. Alternatively, improved FER might be achieved indirectly by selection for increased growth rate and reduced body fat. The aims of this study were (i) to perform a phenotypic analysis of energy partitioning traits among Atlantic salmon families; (ii) to estimate heritability and genetic relationships among feed efficiency and underlying traits; (iii) to determine an optimal breeding strategy to improve feed efficiency in Atlantic salmon.
Results: Moderate genomic heritability estimates were obtained for most traits, e.g. feed intake (0.35), weight gain (0.42), feed efficiency ratio (0.19) and energy density of the gained weight (0.26). Heritability for residual feed intake was 0.04. Genetic correlation between feed efficiency and growth or energy density of the gained weight was 0.68 and -0.64, respectively. A selection index including weight gain and energy density of the gained weight was most beneficial to increase FER. The effect of body energy (reflecting fat deposition) was half of what could be predicted if energy efficiency (EE; energy gain/energy intake) was constant. The fish retained 50 and 49% of the energy and protein intake, respectively. Energy loss was due to heat (29% of intake), faecal loss (18%) and nitrogen excretion (3%). The derived energy and protein budget traits displayed low to moderate genomic heritability (h2 = 0.01-0.31). Protein efficiency reflected FER.
Conclusions: Genetic selection for weight gain and against energy density of the gained weight will improve feed efficiency ratio in Atlantic salmon without the need for individual feed intake records. The results suggest that by selection against body energy, and given the same weight gain, 50% of the reduction in body energy can be realised as reduced feed intake and thus improved FER.
期刊介绍:
Genetics Selection Evolution invites basic, applied and methodological content that will aid the current understanding and the utilization of genetic variability in domestic animal species. Although the focus is on domestic animal species, research on other species is invited if it contributes to the understanding of the use of genetic variability in domestic animals. Genetics Selection Evolution publishes results from all levels of study, from the gene to the quantitative trait, from the individual to the population, the breed or the species. Contributions concerning both the biological approach, from molecular genetics to quantitative genetics, as well as the mathematical approach, from population genetics to statistics, are welcome. Specific areas of interest include but are not limited to: gene and QTL identification, mapping and characterization, analysis of new phenotypes, high-throughput SNP data analysis, functional genomics, cytogenetics, genetic diversity of populations and breeds, genetic evaluation, applied and experimental selection, genomic selection, selection efficiency, and statistical methodology for the genetic analysis of phenotypes with quantitative and mixed inheritance.