Fatty Acid and Transcriptome Profiling of Longissimus Dorsi Muscles between Pig Breeds Differing in Meat Quality

Abstract

Fat and lean pig breeds show obvious differences in meat quality characteristics including the fatty acid composition of muscle. However, the molecular mechanism underlying these phenotypes differences remains unknown. This study compared meat quality traits between Lantang (a Chinese indigenous breed) and Landrace (a typical lean breed). The Lantang pigs showed higher L* values and intramuscular fat content, lower pH45min, pH24h and shear force in longissimus dorsi (LD) muscle than Landrace (P < 0.05). Fatty acid analysis demonstrated the lower monounsaturated fatty acids (MUFA) and higher polyunsaturated fatty acids (PUFA) percentage in Lantang LD than that in Landrace LD (P < 0.05). To further identify candidate genes for fatty acid composition, the transcriptome of LD muscle from the two breeds were measured by microarrays. There were 586 transcripts differentially expressed, of which 267 transcripts were highly expressed in Lantang pigs. After the validation by real-time quantitative PCR, 13 genes were determined as candidate genes for fatty acid composition of muscle, including Stearoyl-CoA desaturase (SCD). Then, a SCD over-expression plasmid was transfected into C2C12 cells to reveal the effect of SCD on the fatty acid composition in vitro. The results showed that SCD over-expression significantly increased PUFA proportion, while reduced that of saturated fatty acids (SFA) in C2C12 cells (P < 0.05). In summary, this study compared the differences of fatty acid composition and transcriptome in two breeds differing in meat quality, and further identified the novel role of SCD in the regulation of PUFA deposition.

The effect of breed and feeding level on carcass composition, fatty acid profile and expression of genes encoding enzymes involved in fat metabolism in two muscles of pigs fed a diet enriched in n-3 fatty acids. A preliminary study

“…To date, differences between breeds in SCD gene expression have not been widely examined, and all available publications are strictly connected with the LD muscle. Our results are in agreement with those of Yu et al (2013) who found that the greater SCD gene expression in the LD muscle of Lantang than in Landrace pigs was accompanied by higher IMF, MUFA and PUFA contents in this muscle. Opposite results were obtained by Gao et al (2011), who reported lower SCD expression in Northeastern Indigenous pigs having a higher IMF content, but the animals were slaughtered on day 150 regardless of their final BW.…”

“…This could be connected with changes in the level of SCD mRNA, the first enzyme converting SFA to MUFA. Moreover, C2C12 myoblasts with overexpression of SCD are also characterised by increased amounts of such PUFA as: LA, ALA, arachidonic acid (C20:4 n-6) and EPA (Yu et al, 2013). In our experiment, SCD gene expression in LD and BF muscles was greater in L990 pigs, which also had higher MUFA and PUFA contents in these muscles.…”

“…Comparing Lantang and Landrace pigs differing in fat content, Yu et al (2013) identified differences in the expression of genes encoding factors taking part either in adipocyte differentiation and function (peroxisome proliferator activated receptor gamma coactivator 1, adiponectin, Kruppel-like factor 5) or fatty acid uptake and transport (lipoprotein lipase, FABP4, apolipoprotein O-like). In our experiment we chose a gene encoding a transcriptional factor controlling adipogenesis and thus the amount of adipocytes -PPARγ -and gene encoding a protein involved in fatty acid transport and a later marker of adipogenesis -FABP-4.…”

“…Therefore, stearoylCoA desaturase (SCD), fatty acid-binding protein 4 (FABP-4), and peroxisome proliferator-activated receptor γ (PPARγ) genes expression was determined. To date, most studies (Gao et al, 2011;Yu et al, 2013) have estimated transcript levels in the LD muscle, whereas there is no data concerning the BF muscle, probably because of problems with sample collection in commercial slaughter houses and the generally greater emphasis placed on the polymorphism of the selected genes. Our planned analysis of both LD and BF muscles should contribute new information on this issue.…”

Effect of different dietary oil sources on the growth performance, blood characteristics, fatty acid profiles, and expression of lipogenic genes in the liver of broiler chickens

“…ND2 variation is significantly associated with the pectoral muscle fat content of chickens (Lu et al 2014). Previous reports showed that the PUFA levels were closely associated with alteration of expression of the body lipid metabolism related genes as hepatic LPIN1 transcript was found to be negatively regulated by the dietary PUFA proportion and its expression of mRNA levels was correlated with the PUFA proportion in muscle (Martin et al 2007;Yu and Shu 2013), FADS2 gene expression level in adipocyte was reported to be negatively correlated with 20:5n-3 and 20:4n-6 (Ralston et al 2015). However, literature about the effects of PUFA on the expression of ND2 in broilers is lacking.…”