Effect of copper deficiency on intestinal gene expression in beef cattle

Abstract

Copper (Cu) deficiency has been shown to impact iron (Fe) metabolism. We compared global gene expression in the duodenum of Cu‐deficient (‐Cu) and Cu‐adequate (+Cu) calves. Calves were born to cows that received −Cu or +Cu diets for 410 days prior to calving. After weaning calves remained on their respective treatments for 275 days. Liver and plasma Cu concentrations indicated that −Cu calves were severely Cu deficient. An oligonucleotide array containing 8,400 bovine mRNAs was used to determine gene expression changes due to Cu deficiency. Expression changes of genes involved in Fe metabolism were of particular interest, given that Cu and Fe metabolism are closely linked. Total RNA was extracted from duodenum mucosal scrapings of Cu+ and Cu− calves. Cy5 and Cy3 labeled cDNA was synthesized to probe three oligonucleotide arrays. A dye swap was also performed to control for dye bias. Arrays were probed overnight and scanned on a ScanArray 4000. Preliminary t‐test results indicated a differential gene expression between −Cu calves and +Cu calves, including genes involving cellular transport, transcription and translation. Interestingly genes involved in Fe metabolism did not demonstrate statistically significant expression changes. This result suggests that perhaps the major link between Cu and Fe metabolism is not at the gene expression level but rather further downstream in the metabolic pathway.