Accepted Article Betaine and arginine supplementation of low protein diets improves plasma lipids but does not affect hepatic fatty acid composition and related gene expression profiling in pigs Marta S Madeira, a Eva A Rolo, a Paula A Lopes, a Denis A Ramos, a Cristina M Alfaia, a Virgínia M R Pires, a Susana V Martins, a Rui M A Pinto, b José A M Prates a * a CIISA, Faculdade de Medicina Veterinária, Universidade de Lisboa, Avenida da Universidade Técnica, Alto da Ajuda, 1300-477 Lisboa, Portugal b iMed.UL, Faculdade de Farmácia, Universidade de Lisboa, Avenida Professor Gama Pinto, 1649-003 Lisboa, Portugal * Correspondence to: José A. M. Prates, Faculdade de Medicina Veterinária, Avenida da Universidade Técnica, Alto da Ajuda, 1300-477 Lisboa, Portugal. Telephone: (+) 351 213652890; Fax: (+) 351 213652895. E-mail: japrates@fmv.ulisboa.pt Running title: Betaine and arginine improve plasma lipids Abstract BACKGROUND: The individual and combined effects of betaine and arginine supplemented to reduced protein diets were investigated on plasma metabolites, hepatic fatty acid composition and mRNA levels of lipid-sensitive factors in commercial pigs. Betaine has previously been shown to reduce carcass fat deposition and arginine improves meat quality of finishing pigs. Forty male crossbred pigs were randomly assigned to one of five diets (n=8): This article is protected by copyright. All rights reserved. This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1002/jsfa.8504