Effect of photoperiod on ovarian morphology, reproductive hormone secretion, and hormone receptor mRNA expression in layer ducks during the pullet phase

文献类型： 外文期刊

第一作者： Wu, Shu-geng

作者： Wu, Shu-geng;Qi, Guang-hai

作者机构：

关键词： ovarian morphology; follicle; layer duck; reproductive hormone; photoperiod

期刊名称：POULTRY SCIENCE （ 影响因子：3.352； 五年影响因子：3.679 ）

ISSN： 0032-5791

年卷期： 2019 年 98 卷 6 期

页码：

收录情况： SCI

摘要： We evaluated the effect of photoperiod on ovarian morphology, reproductive hormone secretion, and hormone receptor mRNA expression in layer ducks during the pullet phase. A total of 480 71-d-old Jinding layer ducks were randomly divided into 5 groups that received 6L (hours of light):18D (hours of darkness), 8L:16D, 10L:14D, 12L:12D, or 14L:10D, respectively. Each group had 6 replicates with 16 birds each. The photoperiod feeding trial lasted 80 d until 150 d of age. The age at first egg (AFE), the total number, and weight of eggs increased linearly with increasing photoperiods (P < 0.05); lower values of AFE occurred with photoperiods >= 8 h, whereas a higher total number and weight of eggs occurred with photoperiods >= 10 h, compared with 6L:18D (P > 0.05). Oviduct weight, ovary percentage, and initial and bare stroma (weight and percentage) increased quadratically with increasing photoperiods (P < 0.05), and 10.24, 10.01, and 10.10 h were the optimal photoperiods for oviduct weight, bare stroma (follicles >= 2 mm in diameter removed) weight, and bare stroma percentage, respectively, as calculated from reliable regression equations (R-2 >= 0.5791). Compared with 6L:18D, 10L:14D had a higher total large white follicle weight, small yellow follicle number, and weight (P < 0.05). In addition, higher serum levels of follicle-stimulating hormone, luteinizing hormone, and progesterone were observed with >= 10-h photoperiods (P < 0.05), as were levels of hormone receptor mRNA expression in ovarian follicles (P < 0.05), with the highest values for both measures at 10L:14D. In the hypothalamus, mRNA expression of gonadotropin-releasing hormone increased in >= 8-h photoperiods, with the highest value at 10L:14D. In contrast, gonadotropin-inhibitory hormone increased in photoperiods >= 12 h (P < 0.05). In conclusion, an appropriate photoperiod led to early sexual maturity and improved the development of reproductive organs and ovarian follicles through effects on reproductive hormones and their receptors; 10 to 10.24 h is an adequate photoperiod for layer ducks during the pullet phase.

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