Genome-wide association study confirm major QTL for backfat fatty acid composition on SSC14 in Duroc pigs

Abstract

BackgroundFatty acid composition contributes importantly to meat quality and is essential to the nutritional value of the meat. Identification of genetic factors underlying levels of fatty acids can be used to breed for pigs with healthier meat. The aim of this study was to conduct genome-wide association studies (GWAS) to identify QTL regions affecting fatty acid composition in backfat from the pig breeds Duroc and Landrace.ResultsUsing data from the Axiom porcine 660 K array, we performed GWAS on 454 Duroc and 659 Landrace boars for fatty acid phenotypes measured by near-infrared spectroscopy (NIRS) technology (C16:0, C16:1n-7, C18:0, C18:1n-9, C18:2n-6, C18:3n-3, total saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids). Two QTL regions on SSC4 and SSC14 were identified in Duroc for the de novo synthesized fatty acids traits, whereas one QTL on SSC8 was detected in Landrace for C16:1n-7. The QTL region on SSC14 has been reported in previous studies and a putative causative mutation has been suggested in the promoter region of the SCD gene. Whole genome re-sequencing data was used for genotype imputation and to fine map the SSC14 QTL region in Norwegian Duroc. This effort confirms the location of the QTL on this chromosome as well as suggesting other putative candidate genes in the region. The most significant single nucleotide polymorphisms (SNPs) located on SSC14 explain between 55 and 76% of the genetic variance and between 27 and 54% of the phenotypic variance for the de novo synthesized fatty acid traits in Norwegian Duroc. For the QTL region on SSC8 in Landrace, the most significant SNP explained 19% of the genetic variance and 5% of the phenotypic variance for C16:1n-7.ConclusionsThis study confirms a major QTL affecting fatty acid composition on SSC14 in Duroc, which can be used in genetic selection to increase the level of fatty acid desaturation. The SSC14 QTL was not segregating in the Landrace population, but another QTL on SSC8 affecting C16:1n-7 was identified and might be used to increase the level of desaturation in meat products from this breed.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-017-3752-0) contains supplementary material, which is available to authorized users.

Dynamic accumulation of fatty acids in duck (Anas platyrhynchos) breast muscle and its correlations with gene expression

“…It has been widely reported that the fatty acid composition of meat can be affected by various factors such as age, sex, and rearing conditions of the animals [7][8][9][10]. In addition, fatty acid compositions are heritable traits, with heritability ranging between 0.2 and 0.6 in various populations of pigs [11,12]. Chickens and ducks of different breeds have been shown to vary in fatty acid composition, suggesting that genetic factors may influence fatty acid composition, and breeding poultry for favorable fatty acid composition is possible [13,14].…”

Fatty acid profile of the backfat layers in four pig breeds

“…In an earlier study, Wood et al (1989) reported that the contents of C18:2n-6 provides the best prediction of fat firmness. According to Seman (2008), the melting point of C18:2n-6 is -5°C which is considerably lower than that of C18:0 (70.1°C) and even C18:1(16.3°C). The low melting point of the fat is associated is various quality issues in the meat products such as reduced cohesiveness (Gandemer et al 2002) and separation between the fat and muscle in dry cured products, as well as softer, undesirable texture and fat smearing in fresh sausages (Legan et al 2007).…”

“…Adipose tissue is of major importance in the farm animals, since its percentage of the body weight is a major determinant for the efficiency of transferring nutrients from feed into food products and thus for the economic value of meat producing animals (Sauerwein et al 2014). In addition to its functions as an energy reservoir and endocrine organ, the adipose tissue of pigs, is an important component of meat together with the other major componentsprotein, water, and ash (Seman 2008). Much of the carcass fat accumulates in the subcutaneous depots (backfat) surrounding the major wholesale cuts, and other fat exists as intermuscular, lying between the muscles.…”

“…Despite the importance of the intramuscular fat, the backfat is also of interest, since it is used in meat processing. The fatty acid composition of the adipose tissues in pigs can be modified through the diet (Morel et al 2006), however, recent studies (Zhang et al 2016;van Son et al 2017) reveal that it is also a heritable qualitative trait and hence breed specific profile of the lipids will not be surprising. The knowledge about the differences that might exist between the breeds is important for the breeding practices aiming to produce animals with high quality meat and also for the further processing into meat products.…”

European Local Pig Breeds - Diversity and Performance. A study of project TREASURE

“…While PUFA are mainly related to nutrition as they cannot be synthesised de novo in pigs and come from exogenous supplies [31], their relative quantities in pig tissues can be altered by oxidation processes and other fatty acids synthesised de novo. In the context of the variability between studies in terms of nutrition and final body weight and age, it is difficult to evaluate to which degree the collected data and the differences observed were influenced by genetic or production system factors, but the importance of the genetic control of fatty acid composition and potential for selective breeding has been emphasised in different pig genotypes [32][33][34][35]. Regarding the nutritional value of pork which has generally high n-6/n-3 ratio, much above the recommended one (<5), studies on local pig breeds show huge variability; however, in some breeds, in particular, Iberian in 'montanera' production, the observed values approach the mentioned recommendation [15,36,37].…”