Transcript profiles in longissimus dorsi muscle and subcutaneous adipose tissue: A comparison of pigs with different postweaning growth rates1

Abstract

Although most pigs recover rapidly from stresses associated with the transition of weaning, a portion of the population lags behind their contemporaries in growth performance. The underlying biological and molecular mechanisms involved in postweaning differences in growth performance are poorly understood. The objective of this experiment was to use transcriptional profiling of skeletal muscle and adipose tissue to develop a better understanding of the metabolic basis for poor weaned-pig transition. A total of 1,054 pigs was reared in commercial conditions and weighed at birth, weaning, and 3 wk postweaning. Transition ADG (tADG) was calculated as the ADG for the 3-wk period postweaning. Nine pigs from both the lowest 10th percentile (low tADG) and the 60th to 70th percentile (high tADG) were harvested at 3 wk postweaning. Differential expression analysis was conducted in longissimus dorsi muscle (LM) and subcutaneous adipose tissue using RNA-Seq methodology. In LM, 768 transcripts were differentially expressed (DE), 327 with higher expression in low tADG and 441 with higher expression in high tADG pigs (q < 0.10). Expression patterns measured in LM by RNA-Seq were verified in 30 of 32 transcripts using quantitative PCR. No DE transcripts were identified in adipose tissue. To identify biological functions potentially underlying the effects of tADG on skeletal muscle metabolism and physiology, functional annotation analysis of the DE transcripts was conducted using DAVID and Pathway Studio analytic tools. The group of DE genes with lower expression in LM of low tADG pigs was enriched in genes with functions related to muscle contraction, glucose metabolism, cytoskeleton organization, muscle development, and response to hormone stimulus (enrichment score > 1.3). The list of DE genes with higher expression in low tADG LM was enriched in genes with functions related to protein catabolism (enrichment score > 1.3). Analysis of known gene-gene interactions identified possible regulators of these differences in gene expression in LM of high and low tADG pigs; these include forkhead box O1 (FOXO1), growth hormone (GH1), and the glucocorticoid receptor (NR3C1). Differences in gene expression between poor transitioning pigs and their contemporaries indicate a shift to decreased protein synthesis, increased protein degradation, and reduced glucose metabolism in the LM of low tADG pigs.

Effects of Birth Weight and Postnatal Nutritional Restriction on Skeletal Muscle Development, Myofiber Maturation, and Metabolic Status of Early-Weaned Piglets

“…A previous study showed that light weaning weight piglets had a greater protein degradation rate and lower protein synthesis as well as reduced glucose metabolism compared with normal littermates [9]. The present result showed that IUGR piglets had greater serum tAA concentration than NBW piglets.…”

“…Skeletal muscles are the key components of growth and play important roles in many physiological activities, such as locomotion, postural maintenance, breathing, and thermogenesis [8,9]. Furthermore, skeletal muscles exhibit remarkable flexibility in the usage of fuel in response to the nutrient intake and energy demands of the organism's adaptation to a variety of conditions, including disease, stress, and reduced nutrient availability [9,10]. It has been well established that the physiological activity of skeletal muscle is mostly determined by the total fiber number and fiber type composition [11].…”

Identification of Genes Related to Growth and Lipid Deposition from Transcriptome Profiles of Pig Muscle Tissue

“…Several RNA-seq studies have been reported in different tissues of pigs, such as the skeletal muscle[ 3 – 8 ], gonad[ 9 ], liver[ 10 , 11 ], adipose tissue[ 12 , 13 ], endometrium[ 14 ],which provided better understanding of the mRNA transcriptome in pig. MicroRNAs (miRNAs) play an important role in post-transcriptional regulation of metabolism in cells, such as β-cells, muscle cells, and adipocytes[ 15 ].…”

Transcriptome Analysis Reveals Long Intergenic Noncoding RNAs Contributed to Growth and Meat Quality Differences between Yorkshire and Wannanhua Pig

“…We performed validation of the relationship between lincRNA and their PTG in another longissimus dorsi muscle dataset, which contained 18 samples (NCBI GEO database, accession GSE65983) [ 38 ]. First, we calculated the expression of lincRNAs and their PTGs by HTSeq [ 39 ].…”