Genetic correlations of intramuscular fat content and fatty acid composition among muscles and with subcutaneous fat in Duroc pigs1

Abstract

There is an increasing interest in including intramuscular fat (IMF) content and fatty acid composition, particularly oleic acid (C18:1) content, in the selection objectives of pig lines for quality pork markets. These traits are costly and can be measured in more than 1 location, so knowing their correlation structure across muscles and with subcutaneous fat (SF) is necessary for developing optimum sampling and recording schemes. We analyzed the genetic and phenotypic correlations of IMF content and composition among 3 of the most relevant muscles (LM, gluteus medius muscle [GM], and semimembranosus muscle [SM]) and with the fatty acid composition of SF. All genetic correlations were positive but variable. For IMF, the genetic correlation between GM and LM was 0.68, and for fatty acids, the genetic correlation ranged from 0.62 for C18:1 to 0.82 for total PUFA. Genetic correlations of GM and LM with SM were much lower: 0.13 to 0.19 for IMF and 0.10 to 0.54 for fatty acids. Correlations for fatty acid composition in SF with GM and LM were moderate to high (0.29-0.53 and 0.43-0.75, respectively) but were null with SM. The expected responses for IMF in the 3 muscles and for C18:1 in each muscle and in SF to selection on records taken from only a single muscle or SF were estimated. Selection for IMF and C18:1 in GM is expected to lead to positive responses in IMF and C18:1 in LM and vice versa, although this can entail genetic lags of 20 to 45% in the muscle not directly selected for. Selection for C18:1 in SF is more effective for C18:1 in LM than in GM and of very limited value for IMF. In conclusion, the genetic correlations of IMF content and fatty acid composition among muscles and with SF, although positive, are variable enough to influence the genetic evaluation scheme for IMF and fat quality. They also indicate that GM and LM can be used alternatively for selection purposes.

Genetic parameters and crossbreeding effects of fat deposition and fatty acid profiles in Iberian pig lines1

“…This mean value was in line with the mean heritability (0.25) reported for Iberian pigs by Fernández et al (2003). This value was lower than the values previously reported for heavy Duroc pigs (Suzuki et al, 2005;Ros-Freixedes et al, 2014) and for Landrace and for lean Large White pigs (Knapp et al, 1997;Hermesch et al, 2000). However, this estimate is in the rank of estimates (from 0.26 to 0.86) reported by Sellier (1998) from 19 different studies in "white" pigs.…”

“…The posterior mean of the genetic additive correlation between BFT and IMF was moderately positive (0.31) with a probability of being greater than 0 of 0.72. This mean value was within the range of the estimates reported for Duroc pigs (Suzuki et al, 2005;Ros-Freixedes et al, 2014). This would seem to indicate that part of the BFT and IMF genetic control is independent.…”

Genetic Marker Discovery in Complex Traits: A Field Example on Fat Content and Composition in Pigs

“…It is the most abundant adipose tissue and for decades it has been selected against to improve the production efficiency of pork. Intramuscular fat content is also influenced by genetic type, ranging from 1.2%–2.7% in Pietrain pigs [5] to 2.7%–4.8% in Duroc pigs [6], although even within breed much wider ranges have been described [7]. IMF is the least abundant adipose tissue in the pig carcass and it has a favorable impact on meat quality, having optimal values around 1.5%–3% in fresh meat [8].…”

The Landscape of DNA Methylation Associated With the Transcriptomic Network of Intramuscular Adipocytes Generates Insight Into Intramuscular Fat Deposition in Chicken

“…Intramuscular fat (IMF) is one of the most important factors that affect meat quality (Fanatico et al, 2007;Ros-Freixedes et al, 2014;Li et al, 2019). Previous researches have indicated that IMF improved the quality of meat by improving the flavor, juiciness and tenderness (Gao and Zhao, 2009).…”