Genetic parameters of backfat fatty acids and carcass traits in Large White pigs

Abstract

Subcutaneous fat thickness and fatty acid composition (FAC) play an important role on seasoning loss and organoleptic characteristics of seasoned hams. Dry-cured ham industry prefers meats with low contents of polyunsaturated fatty acids (PUFA) because these negatively affect fat firmness and ham quality, whereas consumers require higher contents in those fatty acids (FA) for their positive effect on human health. A population of 950 Italian Large White pigs from the Italian National Sib Test Selection Programme was investigated with the aim to estimate heritabilities, genetic and phenotypic correlations of backfat FAC, Semimembranosus muscle intramuscular fat (IMF) content and other carcass traits. The pigs were reared in controlled environmental condition at the same central testing station and were slaughtered at reaching 150 kg live weight. Backfat samples were collected to analyze FAC by gas chromatography. Carcass traits showed heritability levels from 0.087 for estimated carcass lean percentage to 0.361 for hot carcass weight. Heritability values of FA classes were low-to-moderate, all in the range 0.245 for n-3 PUFA to 0.264 for monounsaturated FA (MUFA). Polyunsaturated fatty acids showed a significant genetic correlation with loin thickness (0.128), backfat thickness (-0.124 for backfat measured by Fat-O-Meat'er and -0.175 for backfat measured by calibre) and IMF (-0.102). Obviously, C18:2(n-6) shows similar genetic correlations with the same traits (0.211 with loin thickness, -0.206 with backfat measured by Fat-O-Meat'er, -0.291 with backfat measured by calibre and -0.171 with IMF). Monounsaturated FA, except with the backfat measured by calibre (0.068; P<0.01), do not show genetic correlations with carcass characteristics, whereas a negative genetic correlation was found between MUFA and saturated FA (SFA; -0.339; P<0.001). These results suggest that MUFA/SFA ratio could be increased without interfering with carcass traits. The level of genetic correlations between FA and carcass traits should be taken into account in dealing with the development of selection schemes addressed to modify carcass composition and/or backfat FAC.

Muscle transcriptome analysis identifies genes involved in ciliogenesis and the molecular cascade associated with intramuscular fat content in Large White heavy pigs

“…Several studies reported that meat with a level of IMF below 2.2%-2.5% is associated with detrimental palatability [3,4]. Anyway, due to the negative genetic correlation linking IMF deposition with carcass weight and lean percentage [5], the selection carried out by the swine industry prioritizing production efficiency and increased lean mass growth caused a consistent decrease in IMF depots [6]. IMF is a heritable trait in pigs [5,7] and genetic selection is a promising approach to increase IMF without negatively affecting production efficiency.…”

“…Anyway, due to the negative genetic correlation linking IMF deposition with carcass weight and lean percentage [5], the selection carried out by the swine industry prioritizing production efficiency and increased lean mass growth caused a consistent decrease in IMF depots [6]. IMF is a heritable trait in pigs [5,7] and genetic selection is a promising approach to increase IMF without negatively affecting production efficiency. However, this strategy is confounded by the existence of a high number of Quantitative Trait Loci (QTLs) associated with IMF content [7,8] and by the presence of negative associations with lean mass deposition [5].…”

Genome-wide association study identifies quantitative trait loci regions involved in muscle acidic profile in Large White heavy pigs

“…The study was carried out on a sample of 795 Italian Large White pigs belonging to sib test population reared by the Italian pig breeders Association and described in Davoli et al (2019). Triplets of full sibs (two females and one castrated male) were fattened in the Italian pig breeders Association testing station, where siblings entered at 30-45 days of age.…”

“…In a previous work of ours, the genomic regions harboring these two genes have been identified as loci of interest for subcutaneous FA composition in Italian Large White pigs belonging to a purebred population selected for the production of high-quality dry-cured hams (Zappaterra et al, 2018). The same population was also considered in a previous study, where the genetic parameters of backfat FA composition were investigated (Davoli et al, 2019). Genetics of purebred Italian Large White population has been shaped by the peculiar selection objectives pursued since 1990 by the Italian pig breeders Association.…”

Differential Metabolomics Profiles Identified by CE-TOFMS between High and Low Intramuscular Fat Amount in Fattening Pigs

“…IMF content may vary by breed types, muscle types, genders, ages, feeding conditions, and final slaughter weight [ 1 , 2 , 3 ]. The heritability of IMF content in Duroc breed pigs has been estimated to be moderate to high (0.39 to 0.69) [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. This has led to improvements in the phenotypic value of livestock in recent decades, despite that IMF is recognized as a polygenic trait [ 1 , 12 ].…”