Differential expression of innate immune system genes in liver of beef cattle with divergent phenotypes for RFI

摘要

Residual feed intake (RFI) quantifies inter-animal variances in dry matter intake (DMI) independent of variation in body size and productivity (e.g. growth, milk). In beef cattle, Herd and Arthur (2009) estimated that approximately one-third of the biological variation in RFI was due to inter-animal differences in digestion, heat increment, body composition, and activity, with the remaining variation associated with energy expenditure of metabolic processes. Given that RFI is independent of BW and level of production, it is an ideal trait for discovery of genomic regions (Rolf et al, 2011) and functional genes (Chen et al, 2011) associated with efficiency of feed utilization. Some variation in RFI may be caused by individual differences in immune system function. The immune system is an energetically expensive system. A previous study showed that metabolic heat production and oxygen consumption increased 20-30% in mice that were immunized with a relatively benign antigen (Demas et al., 1997). The objective of this work was to examine whether the genes associated with the immune system were differentially expressed by beef cattle with divergent RFI phenotypes.