Submitted to: Journal of Animal Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/17/2007
Publication Date: 8/8/2007
Citation: Hausman, G.J., Poulos, S.P., Pringle, D.T., Azain, M.J. 2007. The influence of thiazolidinediones on adipogenesis in vitro and in vivo: Potential modifiers of intramuscular adipose tissue deposition in meat animals: a review. Journal of Animal Science. 86(E.Suppl.):E236-E243. Interpretive Summary: Interest in intramuscular or marbling fat cells has developed due to the demand to sustain marbling fat accretion and meat quality as selection for muscle mass continues. Accretion of intramuscular fat cells is associated with many factors but very little is known about the regulation of intramuscular fat cell accretion by specific agents. Thiazolidinediones (TZDs) have physiologically relevant effects on muscle and fat tissue and thus have the potential to modify intramuscular or marbling fat cell development. Oral treatment with TZDs in other species increases intramuscular fat accretion and may do so in pigs. Therefore, oral TZD treatment in vivo may be useful to enhance meat quality in the growing pig.
Technical Abstract: Thiazolidinediones (TZDs) are insulin sensitizing agents currently used for the treatment of type 2 diabetes and are widely used as adipogenic agents since they are ligands of PPAR', a key adipogenic transcription factor. In vivo and in vitro studies of TZDs are reviewed in light of TZDs as potential modifiers of intramuscular or marbling adipogenesis. Thiazolidinediones induce adipogenesis, via PPAR' expression and activation, in a wide range of cell culture systems including human, bovine and pig adipose tissue S-V cell cultures. Studies of porcine S-V cell cultures derived from semitendinosus muscle show that TZDs have the potential to modify intramuscular or marbling adipogenesis. Preadipocyte recruitment was TZD dependent in muscle S-V cultures but TZD independent in adipose S-V cultures. Therefore, thiazolidinedione PPAR' affinity may distinguish marbling preadipocytes from adipose tissue preadipocytes. Thiazolidinedione treatment increases lipid content of muscle in rodents and humans. However, rosiglitazone treatment for 49 d in pigs did not influence muscle lipid content and meat quality but several significant changes in muscle fatty acid composition were observed. Treatment with TZDs during an earlier period of growth may be necessary to enhance marbling deposition in swine.