Abstract:

【Objective】 Sixty-three Landrace×Yorkshire crossbred gilts were allotted to three treatment groups of high (H, 2×maintenace), medium (M, 1.2×maintenace), and low (L, 0.6×maintenace) after mating to study the effects of feed intake level on progesterone secretion, embryonic survival and mRNA expression of fibroblast growth factor receptor 2 (FGFR2), progesterone receptor (PGR) gene in embryo and retinol binding protein 4 (RBP4), folate-binding protein (FBP), uteroferrin (UF) gene in embryo and endometria. 【Method】 Gilts were slaughtered on day 12, 25 and 35 of pregnancy, and serum, uterine flushings, embryos and endometria were collected. ELISA was adopted to determine the progesterone concentration in serum and uterine flushings, and RT-PCR was adopted to determine the genes expression in embryos and endometria. 【Result】 Progesterone concentrations in serum were lower in H than M and L (P＜0.01) on day 12, 25, 35 of pregnancy. In uterine flushings progesterone concentrations was lower in H than M and L (P＜0.05, P＜0.01) on day 12 of pregnancy, and no difference was observed on day 25 of pregnancy. Total viable embryos were greater in M than H group (P＜0.05) on day 12 of pregnancy. No difference was observed between H and L group (P＞0.05). Medium feed intake level significantly increased the relative mRNA expression of FGFR2 and RBP4 in embryo and RBP4, FBP, UF in endometria (P＜0.05) on day 12, 25 and 35 of pregnancy. 【Conclusion】 Medium feed intake level had greater total viable embryos during day 1-35 of pregnancy in gilts. High feed intake level and restricted feeding induced higher or lower secretion of progesterone and decreased expression of FGFR2, RBP4 in embryo and RBP4, FBP, UF in endometrial, resulting in detrimental effects on the development of early embryo.

Key words: feed intake level, gilt, embryonic survival, progesterone, gene expression