Abstract #M222

# M222
Effects of maternal nutrient restriction on bovine placentome and miRNA expression during mid-gestation.
Regina K. Taylor*1, Kayla S. Mangrum1, Christopher T. LeMaster1, Scott L. Pratt1, Nathan M. Long1, 1Clemson University, Clemson, South Carolina.

Primiparous Angus-cross cows (n = 22) were synchronized and AIed with sexed semen from a single Angus sire. Animals were fed at 1.3× (Control [CON]) or 0.55× (Nutrient Restricted [NR]) of maintenance energy and protein requirements based on BW (NRC 1996). Animals were blocked by BCS and BW and assigned to 1 of 3 treatments: CON; (n = 8) d 30–190; NR/CON; (n = 7) NR d 30–110 then CON d 110–190; or CON/NR; (n = 7) CON d 30–110 then NR d 110–190. Cows were killed on d 190 of gestation, and the fetus and placenta collected. Isolation of RNA was performed from flash frozen cotyledon samples (3 subsamples/treatment) using the mirVana microRNA Isolation kit and analyzed using a previously validated microarray. Placentome measures and microRNA expression was analyzed as an ANOVA analysis using appropriate procedures correcting for false discovery rate of microarray data. Total placentome weight and total caruncular weight tended to be decreased (P = 0.056, P = 0.07, respectively) in NR/CON animals vs. CON/NR and CON/CON. Total cotyledonary weight was increased (P = 0.017) in CON/NR animals vs. NR/CON and CON/CON. Ratio of cotyledon weight:caruncle weight was increased (P = 0.02) in NR/CON and CON/NR vs. CON/CON animals. Total placentome surface area tended to be increased (P = 0.09) in CON/NR animals vs. NR/CON and CON/NR. Cotyledons from CON had mdo-miR-195 upregulated (P < 0.01) and 8 downregulated (P < 0.01) miRNAs, including mmu-mir-5105-p3 and bta-miR-2484 vs. NR/CON and CON/NR cotyledons. Cotyledons from NR/CON had mmu-mir-5117-p3_1ss19TA and bta-miR-99b upregulated (P < 0.01) and mmu-mir-5105-p3_1ss24TC and bta-miR29a downregulated (P < 0.01) vs. CON/NR and CON cotyledons. Cotyledons from CON/NR had 11 upregulated (P < 0.01) miRNAs including bta-miR29a and bta-miR2484, and mdo-miR-195 and bta-miR-99b downregulated (P < 0.01) vs. CON and NR/CON cotyledons. The data show that maternal nutrient restriction during early or mid gestation causes asymmetrical fetal growth restriction and affects miRNA regulation differently depending on if the restriction is preceded or followed by a non-restriction period.

Key Words: fetal growth, undernutrition, fetal programming