Abstract
A significant proportion of gilts that enter the herd never farrow a litter and are culled because of anestrus or failure to conceive. Genome-wide association studies for pubertal traits have identified loci involved in neuronal and olfactory pathways, and olfaction is critical for expression of reproductive behavior in mammalian females. We evaluated major olfactory epithelium (MOE) for differential gene expression in nonpubertal, behavioral anestrus and normal cycling early follicular and luteal phase gilts (n = 8/group; average age of 259 days). An average of 50 million paired-end RNA-seq reads were collected from each of the 32 RNA libraries and mapped to Sscrofa 11.1. Differential gene expression was determined using DESeq2. A total of 18,484 genes were expressed with a mean normalized expression value greater than 5. Only four genes were differentially expressed between nonpubertal or behavioral anestrus MOE and their cycling controls (early follicular and luteal, respectively). Comparing cycling follicular and luteal phase gilts showed that 1146 genes were more highly expressed in MOE from follicular phase gilts, whereas 1351 genes were more highly expressed in MOE from luteal phase gilts. Pathways for transmembrane receptor protein tyrosine kinase/growth factor signaling, cell junction and epithelium development were overrepresented in follicular phase MOE and cell cycle, chromatin remodeling, inflammatory response and sensory perception were overrepresented in luteal phase MOE. While 1348 locus IDs were identified for olfactory receptors in MOE, only 160 were expressed at an appreciable level (base mean > 5) in MOE and 16 were more highly expressed in MOE from luteal phase than follicular phase gilts. While few genes were differentially expressed in MOE between prepubertal and anestrus gilts and cycling gilts at the same ovarian stage, the comparison between ovarian stages indicates that MOE gene expression is under hormonal control. USDA is an equal opportunity provider and employer.
Differential gene expression profiling of endometrium during the mid-luteal phase of the estrous cycle between a repeat breeder (RB) and non-RB cows