Association of osteopontin gene with intramuscular fat content and fatty acid composition traits in pigs

Nanthana Pothakam,Watcharapong Naraballobh,Korawan Sringarm,Supamit Mekchay,Pantaporn Supakankul,Worrarak Norseeda,Guisheng Liu,Trisadee Khamlor,Tawatchai Teltathum

doi:10.12982/vis.2021.018

Abstract

Osteopontin (OPN) is a secreted phosphoprotein that is involved in the development of skeletal muscle and fat deposition. The objectives of this study were to identify the polymorphism of the OPN gene and to analyze the association of the OPN gene with intramuscular fat (IMF) content and fatty acid (FA) composition in pigs. Longissimus thoracis (LT) muscle samples taken from the 10-11th rib were collected from a total of 328 Duroc pigs. Genomic DNA samples were extracted from LT muscle tissues using the phenol-chloroform method. IMF content was measured using the ether extraction method and FA composition was measured by gas chromatography. The porcine OPN polymorphisms were identified by DNA sequencing and were genotyped using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The association analysis of the OPN gene with IMF and FA composition traits was performed using a general linear model (GLM). Two polymorphic sites (OPN g.2442-2471indel and g.3836A>G) were found in the 5´-flanking region and intron 1 of the porcine OPN gene. The OPN g.2442-2471indel polymorphism was found to be significantly associated with IMF content and ω3 FA levels (P<0.05). Moreover, OPN g.3836A>G polymorphism was significantly associated with the linolenic acid levels in the muscles of pigs (P<0.05). The results of this study indicate that the OPN gene is important to IMF content, as well as linolenic and ω3 FA levels in pigs, and could be used as a candidate gene to improve fat deposition and fatty acid composition in the muscles of pigs.

Highlights

Intramuscular fat (IMF) content is an economically important trait for the determination of meat quality and is strongly related to the eating quality of meat (Ros-Freixedes et al, 2014; Wood et al, 2004)
We identified polymorphisms in the porcine OPN gene and assessed their effects on IMF content and fatty acid (FA) composition in the Longissimus thoracis (LT) muscle tissues of Duroc pigs
Our results indicated the effects of OPN polymorphisms on IMF content and FA composition in the LT muscle tissue of pigs

Summary

Introduction

Intramuscular fat (IMF) content is an economically important trait for the determination of meat quality and is strongly related to the eating quality of meat (Ros-Freixedes et al, 2014; Wood et al, 2004). High levels of IMF content and FA composition especially, palmitoleic, oleic, and monounsaturated fatty acid (MUFA) are positively associated with the flavor of pork (Cameron et al, 2000; Wood et al, 2004; Zhang et al, 2019). The entire transcriptomic approach has been analyzed along with numerous genes that are related to IMF content and FA composition in various pig breeds (Ropka-Molik et al, 2015). One of these genes is porcine osteopontin (OPN), which is known to be differently expressed in muscle and adipose tissues (Ropka-Molik et al, 2015)

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