Carnitine Enigma: From Antioxidant Action to Vitagene Regulation. Part 2. Transcription Factors and Practical Applications

Abstract

A growing interest has been shown in the potential uses of carnitine in medical practice and animal/poultry industry. The molecular mechanisms accounting for the positive effect of LC on livestock animals are not yet fully understood but many protective effects of LC in various stress conditions reported in literature, have been related to its antioxidant action. Based on the analysis of the recent publications presented in the review it could be concluded that antioxidant actions of carnitine are associated to much extent with redox signaling in the cell. Indeed, LC is shown to upregulate Nrf2 and PPARs and downregulates NF-κB leading to anti-apoptotic and anti-inflammation actions of carnitine. In fact, Nrf2-mediated synthesis of antioxidant enzymes, including SOD, GSH-Px, GR, GST and GSH, in response to carnitine supplementation could be a main driving force of antioxidant action of carnitine and its derivatives. Furthermore, LC and its derivatives are shown to affect vitagene networks resulting in increased adaptive ability to stresses via additional synthesis of protective molecules, including heat shock proteins (HO-1), upregulating sirtuins, thioredoxins and SOD. It seems likely that in biological system in vivo the interactions of the aforementioned mechanisms provide an important place for carnitine to be a crucial part of the integrated antioxidant systems of the animal and human body. Furthermore, direct scavenging ROS and chelating properties of carnitine would be very much relevant to the antioxidant system of the gut. Taking into account low carnitine content in grains and poultry and pig diet formulations with limited amounts of animal proteins, carnitine requirement and possible inadequacy in commercial poultry and pig nutrition should receive more attention. Furthermore, protective roles of carnitine in stress conditions of commercial poultry and pig production, including its immunomodulating properties, are of great importance. Therefore, a development of carnitine-containing antioxidant compositions supplying via drinking water seems to be an important way forward in decreasing the detrimental consequence of various stresses in poultry and pig production.