Dietary L-carnitine alters gene expression in skeletal muscle of piglets

• Published in: Molecular nutrition & food research Vol. 55; no. 3; pp. 419 - 429
• Main Authors: Keller, Janine, Ringseis, Robert, Priebe, Steffen, Guthke, Reinhard, Kluge, Holger, Eder, Klaus
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley-VCH Verlag 01.03.2011; WILEY-VCH Verlag; WILEY‐VCH Verlag; Wiley
• Subjects: Analysis of Variance; Animal Feed; Animal Nutritional Physiological Phenomena; Animal productions; Animals; Biological and medical sciences; Carnitine; Carnitine - pharmacology; cytoskeletal proteins; diet; Diet - veterinary; Dietary Supplements; Down-Regulation; drug effects; Energy Metabolism; Food industries; Fundamental and applied biological sciences. Psychology; Gene array; Gene expression; Gene Expression Profiling; gene expression regulation; genes; Genetic Association Studies; growth & development; insulin; insulin-like growth factor I; Insulin-Like Growth Factor I - metabolism; Male; metabolism; Microarray Analysis; Muscle; muscle fibers; muscle protein; Muscle, Skeletal; Muscle, Skeletal - drug effects; Muscle, Skeletal - growth & development; muscles; pharmacology; Pig; piglets; protein binding; skeletal muscle; Swine; Terrestrial animal productions; Transcription Factor 3; Transcription Factor 3 - metabolism; transcription factors; transcriptome; Up-Regulation; Vertebrates; veterinary; Weight Gain; Vertebrata; Gene array; Meat animals; Farming animal; Mammalia; Gene; Muscle; Artiodactyla; Gene expression; Ungulata; Carnitine; Pig
• ISSN: 1613-4125; 1613-4133; 1613-4133
• DOI: 10.1002/mnfr.201000293

Scope: Carnitine improves protein accretion, muscle mass, and protein:fat accretion in piglets. The underlying mechanisms, however, are largely unknown. Methods and results: To gain insight into mechanisms through which carnitine exerts these effects, we fed piglets either a control or a carnitine-supplemented diet, and analyzed the transcriptome in skeletal muscle. Carnitine concentrations in plasma and muscle were about four-fold higher in the carnitine group when compared to the control group. Transcript profiling revealed 211 genes to be differentially expressed in muscle by carnitine supplementation. The identified genes were mainly involved in molecular processes such as cytoskeletal protein binding, insulin-like growth factor (IGF) binding, transcription factor activity, and insulin receptor binding. Identified genes with the molecular function transcription factor activity encoded primarily transcription factors, most of which were down-regulated by carnitine, including pro-apoptotic transcription factors such as proto-oncogene c-fos, proto-oncogene c-jun and activating transcription factor 3. Furthermore, atrophy-related genes such as atrogin-1, MuRF1, and DRE1 were significantly down-regulated by carnitine. IGF signalling and insulin signalling were identified as significantly up-regulated regulatory pathways in the carnitine group. Conclusion: Carnitine may have beneficial effects on skeletal muscle mass through stimulating the anabolic IGF-1 pathway and suppressing pro-apoptotic and atrophy-related genes, which are involved in apoptosis of muscle fibers and proteolysis of muscle proteins, respectively.