Identifying miRNA-mRNA regulatory networks on extreme n-6/n-3 polyunsaturated fatty acid ratio expression profiles in porcine skeletal muscle

Effects of Feeding Corn Distillers Dried Grains with Solubles on Muscle Quality Traits and Lipidomics Profiling of Finishing Pigs

This study investigated the effects of adding corn distillers dried grains with solubles (DDGS) to the diet on the meat quality, chemical composition, fatty acid composition, and lipidomics profiling in the longissimus thoracis (LT) of finishing pigs. Twenty-four healthy crossbred pigs (average body weight 61.23 ± 3.25 kg) were randomly divided into two groups with three replicates per group and four pigs per pen. The control group (CON) was fed a basal diet, and the DDGS group was fed an experimental diet with 30% DDGS. The results show that adding DDGS to the diet increases the yellowness (b*), chroma (C*), linoleic acid (C18:2n-6) percentages, polyunsaturated fatty acid (PUFA) percentages and iodine value of LT (p < 0.05). Based on LC-ESI-MS/MS, 1456 lipids from 6 classes or 44 subclasses in LT were analyzed, and 50 differential lipids were observed. Triglyceride (TG) with C18:2n-6 side chains and ceramide alpha-hydroxy fatty acid-sphingosine (Cer-AS) contents increased significantly, and the decrease in multiple glycerophospholipids (GPs) content may be related to differences in the glycerophospholipid metabolic pathway. Correlation analysis suggests that triglycerides with C18:2n-6 side chains may be one of the reasons for the changes in b* and C* values in the LT. In conclusion, feeding DDGS affects the meat quality and fatty acid composition and may affect the lipid profile in the LT of finishing pigs by regulating lipid metabolism.

Exon-intron split analysis reveals posttranscriptional regulatory signals induced by high and low n-6/n-3 polyunsaturated fatty acid ratio diets in piglets

Polyunsaturated fatty acids (PUFA), such as omega-6 (n-6) and omega-3 (n-3), play a vital role in nutrient metabolism, inflammatory response, and gene regulation. microRNAs (miRNA), which can potentially degrade targeted messenger RNAs (mRNA) and/or inhibit their translation, might play a relevant role in PUFA-related changes in gene expression. Although differential expression analyses can provide a comprehensive picture of gene expression variation, they are unable to disentangle when in the mRNA life cycle the regulation of expression is taking place, including any putative functional miRNA-driven repression. To capture this, we used an exon-intron split analysis (EISA) approach to account for posttranscriptional changes in response to extreme values of n-6/n-3 PUFA ratio. Longissimus dorsi muscle samples of male and female piglets from sows fed with n-6/n-3 PUFA ratio of 13:1 (SOY) or 4:1 (LIN), were analyzed in a bidirectional contrast (LIN vs. SOY, SOY vs. LIN). Our results allowed the identification of genes showing strong posttranscriptional downregulation signals putatively targeted by significantly upregulated miRNA. Moreover, we identified genes primarily involved in the regulation of lipid-related metabolism and immune response, which may be associated with the pro- and anti-inflammatory functions of the n-6 and n-3 PUFA, respectively. EISA allowed us to uncover regulatory networks complementing canonical differential expression analyses, thus providing a more comprehensive view of muscle metabolic changes in response to PUFA concentration.