| Insulin-like growth factor-I (IGF-I) and Insulin-like growth factor-II (IGF-II) are molecular similar to the peptide and insulin protein substances, as are physiological role of growth hormone is produced during an active protein or peptide to be material. IGF-I and IGF-II-mediated cell growth and promote a variety of tissue metabolism, reproductive function of animals has an important regulatory role. Supplementary feeding in luteal phase does not affect the FSH, estrogen and progesterone secretion, but promote follicular development. Supplementary feeding promotes IGF-IR and IGFBP2gene expression in ovarian follicles. Luteal phase is short feed restriction in increased FSH, estrogen and progesterone secretion, an increase of free fatty acids and cholesterol content changed large luteal phase follicles in the environment, inhibition of follicular development. This study tested whether the effect of the different feeding levels on the concentration of blood and follicular fluid IGF-I, IGF-II gene and on the expression of the other receptor gene in Sheep. As nutrition affect reproductive performance of sheep laid the foundation for the molecular regulation mechanism, scientific development of large-scale sheep farm system before breeding ewes fed to provide reference. Results are as follows:1. Effect of different feeding levels on the concentration of blood and follicular fluid IGF-I and IGF-II in Hu SheepThe effect of the different feeding levels on the concentration of blood and follicular fluid IGF-I and IGF-II gene in Hu Sheep was not significant. In the first estrus cycle7,8,10and12days, the effect of the different feeding levels on the concentration of blood and follicular fluid IGF-I and IGF-II gene in Hu Sheep no significant difference. In luteal phase, the concentration of blood fluid IGF-I was higher than the concentration of blood fluid IGF-II, but the concentration of follicular fluid IGF-I was less than the concentration of follicular fluid IGF-â…¡.Luteal phase short period of follicular development and blood feeding inhibition of IGF-I and IGF-II levels are not related. Large follicles in IGF-II than IGF-I has a more important role.2. Effect of different feeding levels on the expression IGF-IR and IGFBP2gene Hypothalamic-pituitary-ovarian axis in Hu SheepThe effect of the different feeding levels on the expression IGF-IR and IGFBP2gene Hypothalamic-Pituitary-Ovarian axis in Hu Sheep results are as follows:Restricted feeding group of IGF-IR gene expression level lower than the average feeding group, but the significant difference only in expression in the hypothalamus(P<0.05). In the hypothalamus, pituitary and ovary restricted feeding group with feeding group IGFBP2gene expression levels were not significantly different. The amount of reduce on the expression of Hypothalamic IGF-IR gene may be is one of the reasons inhibiting follicular development Luteal period fed. |
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