Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 3/13/2013
Publication Date: 7/20/2013
Citation: Lindholm-Perry, A.K., Rempel, L.A., Hales, K.E., Oliver, W.T., Freetly, H.C., Kuehn, L.A. 2013. Ruminal and adipose gene expression in beef steers selected for diverse feed intake and gain phenotypes [abstract]. Journal of Animal Science Supplement. 91(E-Supplement 2):629.
Technical Abstract: Limited information exists regarding the genes responsible for phenotypic variation in feed efficiency. To determine whether cattle feed intake or growth phenotypes are related to transcript abundance of genes expressed in the rumen and adipose, the variation in five candidate genes from two groups of steers (n = 32) with differential feed intake and gain phenotypes were examined. Steers were selected from extremes of four relative quadrants (high intake-high gain, low intake-high gain, low intake-low gain, high intake-low gain). Tissue samples were collected after harvest from steers in the fall and spring seasons of 2012. The transcript abundance of candidate genes fatty acid synthase (FASN), fat mass and obesity (FTO) and DNA protein kinase (DNA-PK) in adipose tissue and Rho-gamma (RHOG), and protein kinase, AMP-activated, gamma 2 non-catalytic subunit (PRKAG2) in the rumen were analyzed. Total RNA was extracted and transcribed into cDNA for use with quantitative real-time PCR. Normalized raw data was analyzed by season for relationships between transcript level and gain or intake. The relative expression of FASN, FTO and DNA-PK were correlated with each other in adipose tissue (r = 0.63 to 0.83; P = 0.002), while rumen expression of RHOG and PRKAG2 were not correlated (r = 0.228; P = 0.2). The relationship between feed intake, gain, and expression depended upon season. Data were blocked by season to account for diet contribution of either dry-rolled corn or high-moisture corn. In the animals from the fall season on a dry-rolled corn diet, the relative expression of PRKAG2 in the rumen and FTO in the adipose was correlated (P = 0.04) with intake. In animals from the spring season on a high-moisture corn diet, RHOG in the rumen was significantly correlated with intake (P = 0.02). The variation in response by season is likely due to a change in diet between season affecting rumen function and adipogenesis