title: Central Role of the PPARγ Gene Network in Coordinating Beef Cattle Intramuscular Adipogenesis in Response to Weaning Age and Nutrition.
abstract: Adipogenic/lipogenic transcriptional networks regulating intramuscular fat deposition (IMF) in response to weaning age and dietary starch level were studied. The longissimus muscle (LM) of beef steers on an early weaning (141 days age) plus high-starch diet (EWS) or a normal weaning (NW, 222 days age) plus starch creep-feed diet (CFS) was biopsied at 0 (EW), 25, 50, 96 (NW), 167, and 222 (pre-slaughter) days. Expression patterns of 35 target genes were studied. From NW through slaughter, all steers received the same high-starch diet. In EWS steers the expression of PPARG, other adipogenic (CEBPA, ZFP423) and lipogenic (THRSP, SREBF1, INSIG1) activators, and several enzymes (FASN, SCD, ELOVL6, PCK1, DGAT2) that participate in the process of IMF increased gradually to a peak between 96 and 167 days on treatment. Steers in NW did not achieve similar expression levels even by 222 days on treatment, suggesting a blunted response even when fed a high-starch diet after weaning. High-starch feeding at an early age (EWS) triggers precocious and sustained adipogenesis, resulting in greater marbling.
authors: Mammalian NutriPhysioGenomics, Department of Animal Sciences, University of Illinois, Urbana, Illinois, USA.
authors: Sonia J
authors: SJ
authors: Moisá
authors: Department of Animal Sciences, University of Illinois, Urbana, Illinois, USA.
authors: Daniel W
authors: DW
authors: Shike
authors: Department of Animal Science, University of Arizona, Tucson, Arizona, USA.
authors: Dan B
authors: DB
authors: Faulkner
authors: Department of Animal Sciences, University of Illinois, Urbana, Illinois, USA.
authors: William T
authors: WT
authors: Meteer
authors: Department of Animal Science, University of Missouri, Columbia, Missouri, USA.
authors: Duane
authors: D
authors: Keisler
authors: Mammalian NutriPhysioGenomics, Department of Animal Sciences, University of Illinois, Urbana, Illinois, USA. ; Department of Animal Sciences, University of Illinois, Urbana, Illinois, USA. ; Division of Nutritional Sciences, Illinois Informatics Institute, University of Illinois, Urbana, Illinois, USA.
authors: Juan J
authors: JJ
authors: Loor
keywords: adipogenesis; marbling; nutrition; transcriptomics; weaning