Uncovering the mechanism whereby dietary nicotinic acid increases the intramuscular fat content in finishing steers by RNA sequencing analysis

Abstract

In our previous study, we found that a higher dosage of nicotinic acid (NA) in the diet dramatically increases intramuscular fat (IMF) content and improves meat quality in finishing steers. We hypothesised that increased IMF results from the regulation of genes associated with adipogenesis. To address this hypothesis, RNA-seq was used to investigate gene-expression profiles of longissimus muscles from the same 16 cattle that were also used in our previous study and treated with or without dietary NA. Four cDNA libraries were constructed and sequenced. The repeatability and reproducibility of RNA-seq data were confirmed by quantitative reverse-transcription polymerase-chain reaction. In total, 123 differentially expressed genes (DEGs) were identified between longissimus muscles treated and those not treated with dietary NA. Of the 123 DEGs, 117 genes were upregulated by the NA treatment. These DEGs were enriched in 21 pathways, including the extracellular matrix (ECM) –receptor interaction, PPAR signalling pathway, adipocytokine signalling pathway and transforming growth factor-β signalling pathway, all of which are associated with lipid metabolism. Furthermore, candidate genes related to adipocyte differentiation and adipogenesis (PLIN1, PLIN2, ADPN, LEP, LCN2 and SOCS3), lipid metabolism (FABP4, RBP4, GAL, ANXA1, ANXA2 and PTX3) and fatty acid synthesis and esterification (ELOVL6, ACSM1, SOT1 and PTGIS) were upregulated in the NA group. Three genes involved in glucose metabolism (PGAM1, UGDH and GLUT3) were also transcriptionally upregulated. However, MYH4 that encodes glycolytic Type IIb muscle fibres was downregulated by dietary NA. These gene expression results indicated a confirmation of our hypothesis that dietary NA increases the IMF content of longissimus muscle through upregulating the expression of the genes related to adipocyte differentiation, adipogenesis and lipid and glucose metabolism.

Major quantitative trait loci influencing milk production and conformation traits in Guernsey dairy cattle detected on Bos taurus autosome 19

“…The MYH10 gene is a member of the myosin superfamily of protein-coding genes in cattle, humans, mice, chickens, sheep, and several other species. The MYH10 gene is associated with skeletal muscle in human (Mascarello et al, 2016), muscle characteristics in beef cattle (Yang et al, 2019) and pigs (Óvilo et al, 2014), and body size in sheep (Kominakis et al, 2017;Signer-Hasler et al, 2019). In Holstein cattle, the MYH10 gene is associated with milk production (Do et al, 2017) and body conformation traits (Abo-Ismail et al, 2017;Jiang et al, 2019), which is consistent with our findings.…”

Impact of dietary Lactobacillus supplementation on intramuscular fat deposition and meat quality of Sunit sheep

“…There were some ways to increase IMF content, for example, Sun et al (2020) suggested that the IMF deposition of sheep was promoted by mulberry leaves diets which may be related to the fact that mulberry leaf flavonoids can increase insulin levels in animals. Yang et al (2019) indicated a higher dosage of nicotinic acid dietary increased the IMF deposition by upregulating the expression of genes related to adipocyte differentiation, adipogenesis, and lipid and glucose metabolism based on transcriptomics. We found that dietary Lactobacillus supplementation could increase IMF of sheep by regulating lipid metabolism‐related pathways based on metabonomics, the mechanism of which will be discussed later.…”

RNA-Seq Analysis Reveals the Potential Molecular Mechanisms of Puerarin on Intramuscular Fat Deposition in Heat-Stressed Beef Cattle

“…GO enrichment analysis was used to map all DEGs to GO terms in the GO database. 2 The significance was calculated using a hypergeometric test by Yang ( 18 ).…”