Key metabolic pathways associated with differences in weight maintenance and gain in mature cow skeletal and adipose tissue

Abstract Text: During the production year of a cow, the majority of nutrients are used to support maintenance. Differences in feedstuff utilization and metabolism can impact the ability of the cow to meet maintenance requirements. Tissue specific metabolism is critical to energy homeostasis of the animal, and therefore regulation of metabolism is critical to understand. The objective of this research was to determine whether cows that differ in efficiency of weight maintenance and weight gain differ in the relative abundance of transcripts associated with protein and lipid turnover of skeletal muscle and adipose tissue, respectively. Crossbred cows (n = 121) were feed restricted for 112 d followed by an ad libitum feeding period for 98 d. Individual feed intake was monitored and body weights were collected to estimate average daily gain (ADG). Adipose and muscle biopsies were collected at d 105 of restricted feeding and at d 49 of ad libitum feeding. Total RNA was extracted from these tissues of the cows with the highest (n = 6) and the lowest (n = 6) ADG during the ad libitum period. The Affymetrix GeneAtlas microarray system was used to determine relative transcript abundance differences between ADG classes within feeding periods and tissue type. Subsequent analyses using the Database for Annotation, Visualization, and Integrated Discovery (DAVID) and Ingenuity Pathway Analysis (IPA) programs identified key gene clusters and pathways associated with differential gene expression, largely including pathways associated with lipid and carbohydrate metabolism, cell-cell signaling and interaction, and cellular function and maintenance. These data suggest key metabolic pathways may be critical to differences in weight maintenance and gain.

Keywords: adipose tissue, metabolism, skeletal muscle