| Vasoactive intestinal peptide (VIP) belongs to the secretin-glucagon family, and it is made up of28amion acids. VIP and its receptor have the wide range of distribution, and play various biological functions as a gastrointestinal hormone and an important neurotransmitter. So far, the studies of VIP has gained rich results, especially in the broodiness of the poultry, but no reports are found in different physiology stages of Wanxi white goose. In the current study, the immune-fluorescence and laser confocal microscspy were used to explore the distribution of VIP in hypothalamus, pituitary and ovary of Wanxi white goose at puberty, laying period, non-laying period and broody period, in addition, the radioimmunoassay and ELISA were used to further clear the change of VIP and gonadal hormone in different physiology stage of Wanxi white goose.Results showed that:VIP had different expression in hypothalamus, anterior pituitary and ovary of puberty, laying period, non-laying period and broody period Wanxi white goose.(1) The VIP mainly distributed in the nucleus periventvicularis accuatas, the nucleus paramedianus and the nucleus medialis hypothalami of hypothalamus in the physiology stages above, and the immune-fluorescence intensity of broody period was the highest than those of the other three physiology stages(P<0.05), the immune-fluorescence intensity of non-laying period taked second place, in addition, the mean immune-fluorescence intensity between the broody period and the non-laying period was not significant(P>0.05), but between the non-laying period and laying period was significant(P<0.05); the expression of VIP in the puberty was the weakest, the mean immune-fluorescence between the puberty and the laying period was not significant(P>0.05).(2) The VIP mainly distributed in the anterior pituitary of the different physiology stages above, and the positive expression of VIP in anterior pituitary was the same as it in the hypothalamus, that was, the expression of VIP in broody period was the strongest(P<0.05), the non-laying period taked second place, and the puberty was the weakest(P<0.05).(3) The VIP immunoreactive positive cells in all the physiology stages above, mainly distributed in the follicles and there were some differences in different stages and distribution sites. A few positive immunoreaction cells were observed in the primordial follicles at puberty; and VIP mainly in the primary oocytes and the follicle granular layer at non-laying period; the follicle granular layer and primary oocytes of non-laying period and broody period had the more immune positive expression; in addition, the positive expression regular of VIP in anterior pituitary was the same as it in the hypothalamus and anterior pituitary in all physiology stages above.(4) The serum concentration of VIP was the highest in broody period, the non-laying period taked second place, the puberty was the lowest, and the concentration between the puberty and the laying period was not significant(P>0.05), but the level of VIP among various other physiological phases were all significant(P<0.05).(5) The estradiol and progesterone in the serum of laying period were the highest, and in puberty were the lowest, the concentration between the non-laying period and the broody period was not significant(P>0.05), and the concentration of them were between the puberty and the laying period.In the conclusion:(1) The expression of VIP in hypothalamus, anterior pituitary and ovary was the highest in broody period, the puberty were the lowest, and the non-laying period was stronger than the laying period, suggesting that the VIP is associated with the broodiness of Wanxi white goose.(2) The serum concentration of VIP was the highest in broody period, and the lowest in puberty, the non-laying period was lower than the broody period, but it was higher than the laying period, suggesting that the VIP have some role in the broodiness of Wanxi white goose.(3) The estradiol and progesterone in the serum of laying period were the highest, and in non-laying period and broody period were lower, in addition, the estradiol and progesterone were negatively related to the VIP after the the laying period of the Wanxi white goose. |
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