Dataset Information

Gene Expression and Fatty Acid Profiling in Longissimus thoracis Muscle, Subcutaneous Fat, and Liver of Light Lambs in Response to Concentrate or Alfalfa Grazing.

ABSTRACT: A better understanding of gene expression and metabolic pathways in response to a feeding system is critical for identifying key physiological processes and genes associated with polyunsaturated fatty acid (PUFA) content in lamb meat. The main objective of this study was to investigate transcriptional changes in L. thoracis (LT) muscle, liver, and subcutaneous fat (SF) of lambs that grazed alfalfa (ALF) and concentrate-fed (CON) slaughtered at 23 kg and using the Affymetrix Ovine Gene 1.1 ST whole-genome array. The study also evaluated the relationship between meat traits in LT muscle, including color, pigments and lipid oxidation during 7 days of display, ?-tocopherol content, intramuscular fat (IMF) content and the fatty acid (FA) profile. Lambs that grazed on alfalfa had a greater ?-tocopherol concentration in plasma than CON lambs (P < 0.05). The treatment did not affect the IMF content, meat color or pigments (P > 0.05). Grazing increased the ?-tocopherol content (P < 0.001) and decreased lipid oxidation on day 7 of display (P < 0.05) in LT muscle. The ALF group contained a greater amount of conjugated linoleic acid (CLA), C18:3 n-3, C20:5 n-3, C22:5 n-3, and C22:6 n-3 than did the CON group (P < 0.05). We identified 41, 96 and four genes differentially expressed in LT muscle, liver, and subcutaneous fat, respectively. The most enriched biological processes in LT muscle were skeletal muscle tissue development, being the genes related to catabolic and lipid processes downregulated, except for CPT1B, which was upregulated in the ALF lambs. Animals grazing alfalfa had lower expression of desaturase enzymes in the liver (FADS1 and FADS2), which regulate unsaturation of fatty acids and are directly involved in the metabolism of n-3 PUFA series. The results found in the current study showed that ingesting diets richer in n-3 PUFA might have negative effects on the de novo synthesis of n-3 PUFA by downregulating the FADS1 and FADS2 expression. However, feeding diets poorer in n-3 PUFA can promote fatty acid desaturation, which makes these two genes attractive candidates for altering the content of PUFAs in meat.

SUBMITTER: Dervishi E

PROVIDER: S-EPMC6834778 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Gene Expression and Fatty Acid Profiling in <i>Longissimus thoracis</i> Muscle, Subcutaneous Fat, and Liver of Light Lambs in Response to Concentrate or Alfalfa Grazing.

Dervishi Elda E González-Calvo Laura L Blanco Mireia M Joy Margalida M Sarto Pilar P Martin-Hernandez R R Ordovás Jose M JM Serrano Magdalena M Calvo Jorge H JH

Frontiers in genetics 20191031

A better understanding of gene expression and metabolic pathways in response to a feeding system is critical for identifying key physiological processes and genes associated with polyunsaturated fatty acid (PUFA) content in lamb meat. The main objective of this study was to investigate transcriptional changes in <i>L. thoracis</i> (LT) muscle, liver, and subcutaneous fat (SF) of lambs that grazed alfalfa (ALF) and concentrate-fed (CON) slaughtered at 23 kg and using the Affymetrix Ovine Gene 1.1 ...[more]

PMID: 31737049

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Project description:Feeding animals with either concentrates supplemented with vitamin E or alfalfa grazing has been proven to reduce the oxidative process that occurs in meat products. Indoor-kept lambs were fed a standard concentrate (n=7, C) or concentrate supplemented with vitamin E (n=7, VE) for 30 days before slaughtering all animals at 22–24 kg of live weight. Simultaneously, 7 unweaned lambs grazed in alfalfa paddocks (ALF) with their dams. Global transcriptomic data of longissimus thoracis (LT) muscle and subcutaneous fat (SF) with the Affymetrix® Ovine Gene 1.1 microarray was used. In LT muscle when ALF group was compared with C group, were identified 41 genes differentially expressed. Among these genes 32 were down- regulated and 9 were up- regulated. Meanwhile when VE treatment was compared with C group were identified a total of 29 genes, 26 were down- regulated and 3 genes were up- regulated. In SF when ALF treatment was compared with C, were identified only 4 genes differentially expressed, all of them up-regulated in ALF group. Meanwhile when VE treatment was compared with C group, were identified a total of 330 genes. Among them, 295 genes were up- regulated and 35 were down- regulated. In LT muscle the clusters corresponding to gene expression profiles from treatments ALF, C and VE were clearly separated from each other. In SF, ALF group, overlap with VE and C treatments, however, VE and C clearly were separate in different clusters. These differentially expressed genes were selected for a functional analysis by using DAVID. In LT muscle some of the identified significant biological processes were catabolic and lipid process (down-regulated, except CPT1B) (CPT1B, PLA2G16, SPSB1, LRTOMT, PLCD4, FBXO9, CNBP and CYP27A1) and muscle organ differentiation (down-regulated) (CPT1B, MYOD1, MYLK2 and MSTN) in ALF; whereas intracellular signaling cascade (IGF1R, DEF8, AKAP7 and CISH) was down-regulated. In SF, vitamin E supplementation had an important effect; most of the genes were up-regulated. DAVID analysis showed that biosynthesis lipid pathway was the most represented with 20 genes, such as EBP, MVD, CYP51A1, DHCR7, HMGCS1, LSS and FDFT1 implicated in cholesterol synthesis. Further exploration of the links between these genes and vitamin E will lead to a better understanding of how vitamin E affects the oxidative process that occurs in meat products.

Project description:Fatty acid (FA) composition contributes greatly to the quality and nutritional value of lamb meat. In the present study, FA was measured in longissimus thoracis (LT) muscles of 1,085 Hu sheep using gas chromatography. Comparative transcriptomic analysis was conducted in LT muscles to identify differentially expressed genes (DEGs) between six individuals with high polyunsaturated fatty acids (H-PUFA, 15.27% ± 0.42%) and six with low PUFA (L-PUFA, 5.22% ± 0.25%). Subsequently, the single nucleotide polymorphisms (SNPs) in a candidate gene PLIN2 were correlated with FA traits. The results showed a total of 29 FA compositions and 8 FA groups were identified, with the highest content of monounsaturated fatty acids (MUFA, 46.54%, mainly C18:1n9c), followed by saturated fatty acids (SFA, 44.32%, mainly C16:0), and PUFA (8.72%, mainly C18:2n6c), and significant correlations were observed among the most of FA traits. Transcriptomic analyses identified 110 upregulated and 302 downregulated DEGs between H-PUFA and L-PUFA groups. The functional enrichment analysis revealed three significant Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways and 17 gene ontology (GO) terms, in which regulation of lipolysis in adipocytes, the AMPK signaling pathway, and the PPAR signaling pathway may play important roles in FA metabolism and biosynthesis. In addition, weighted gene co-expression network analysis (WGCNA) identified 37 module genes associated with PUFA-related traits. In general, PLIN1, LIPE, FABP4, LEP, ACACA, ADIPOQ, SCD, PCK2, FASN, PLIN2, LPL, FABP3, THRSP, and ACADVL may have a great impact on PUFA metabolism and lipid deposition. Four SNPs within PLIN2 were significantly associated with FA. Of those, SNP1 (g.287 G>A) was significantly associated with C18:1n9c and MUFA, and SNP4 (g.7807 T>C) was significantly correlated with PUFA (C18:3n3). In addition, the combined genotype of SNP1 (g.287 G>A), SNP3 (g.7664 T>C), and SNP4 (g.7807 T>C) were significantly correlated with C16:1, C17:0, C18:1C6, PUFA (C18:3n3, C22:6n3), and n-6/n-3 PUFA. These results contribute to the knowledge of the biological mechanisms and genetic markers involved in the composition of FA in Hu sheep.

Dataset Information

Gene Expression and Fatty Acid Profiling in Longissimus thoracis Muscle, Subcutaneous Fat, and Liver of Light Lambs in Response to Concentrate or Alfalfa Grazing.

Publications

Gene Expression and Fatty Acid Profiling in <i>Longissimus thoracis</i> Muscle, Subcutaneous Fat, and Liver of Light Lambs in Response to Concentrate or Alfalfa Grazing.

Similar Datasets

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