The effect of underfeeding on gene expression in the bovine tract during postpartum

This study aimed to investigate the effect of a mild underfeeding on global gene expression in the oviduct, the endometrium and the corpus luteum between 4 and 15 days post-ovulation in postpartum (PP) Holstein cows. Four control cows (C) received 100% of energy and protein requirements after calving when 4 underfed (U) received 80% of the control diet. Oestrus synchronization treatment was applied to induce ovulation on D80 PP. Oviduct, ovaries and the anterior part of each uterine horn were recovered chirurgically 4, 8, 12 and 15 days after ovulation. Gene expression was assessed on a dedicated 10K array and statistically analyzed on pools across the oestrus cycle days. Tissues appeared divergently "diet-responsive" as no differentially expressed gene (DEG) in the corpus luteum between U and C were highlighted, conversely to 293 DEGs in the oviduct vs. 1 in endometrium under a False discovery rate (FDR)<0.11, and 3830 DEGs vs. 28 respectively under a FDR<0.30. Pathways involved immunity, lipid catabolism and cell proliferation. However, once correlated with dedicated statistics (regularized canonical correlation analysis) to the evolution of 6 plasmatic markers measured weekly over 80 days, IGF-1, insulin, beta-Hydroxybutyrate and genes potentially implied in tissue repair mechanisms (e.g. FABP5/CRABP2, ELF1, TCEA1, NF-kB, TGF-beta1, HNF4A) became relevant to dairy cow physiology during PP in the oviduct and the endometrium. Keywords: Postpartum dairy cows, induced cycle, mild underfeeding, genital tract, gene-metabolites correlations Total RNA from each tissue (endometrium, corpus luteum, oviduct) were indirectly labelled using "random" hexamers. One independent target per tissue and per diet was generated and hybridised onto one array. 4 measurements per diet were generated.