Department of Animal Physiology and Endocrinology, University of Agriculture in Krakow, Krakow, Poland.
Department of Animal Physiology and Endocrinology, University of Agriculture in Krakow, Krakow, Poland.
Domest Anim Endocrinol. 2019 Oct;69:84-95. doi: 10.1016/j.domaniend.2019.05.001. Epub 2019 Jun 7.
This study was undertaken to examine the effect of GH treatment during a pause in laying on (1) ovarian follicle formation, growth (folliculogenesis), and atresia; (2) follicle cell proliferation and apoptosis; and (3) mRNA expression of selected yolk-specific proteins in the chicken liver. A pause in egg laying was induced by food deprivation for 5 d, followed by feeding every other day, and then feeding daily from day 10 onward. Birds were divided into 3 groups: control (n = 18) fed ad libitum, subjected to a pause in laying (n = 18), and subjected to a pause in laying and injected every day with 200 μg/kg BW of chicken GH (chGH; n = 18). The liver, ovarian stroma, and follicles were isolated from the hens of each group on days 6 (ovary regression), 13 (ovary recrudescence), and 17 or 20 (ovary rejuvenated) of the experiment. The results showed that injection of chGH during fasting (1) increased the number of follicles <1 mm and proliferating cell nuclear antigen (PCNA)-positive (proliferating) cells in these follicles; (2) attenuated the expression of PCNA and survivin mRNA in the white follicles and the activity of caspases 3, 8, and 9 in the stroma and white follicles; (3) intensified the atresia of yellow hierarchical follicles; and (4) deepened the effect of starvation on egg yolk gene expression concomitantly with considerably increased IGF-1 transcription levels in the liver (P < 0.05 to P < 0.001). Prolongation of chGH injections into the refeeding period did not exert pronounced effects on the examined parameters. In summary, the results provide evidence that GH promotes the formation and development of prehierarchical follicles in the hen ovary during a pause in laying by regulating cell proliferation and apoptosis. Alterations in cell proliferation- and apoptosis-related gene expression or enzyme activity in ovarian follicles as well as the expression of egg yolk proteins in the liver after chGH treatment strongly suggest that this hormone is involved in determining the rate of regression and rejuvenation of the chicken ovary during a pause in laying.
本研究旨在探讨在产蛋暂停期间(1)卵巢卵泡形成、生长(卵泡发生)和闭锁;(2)卵泡细胞增殖和凋亡;以及(3)鸡肝中选定卵黄特异性蛋白的 mRNA 表达,GH 治疗对鸡的影响。通过禁食 5 天诱导产蛋暂停,然后每隔一天喂食,从第 10 天开始每天喂食。将鸟类分为 3 组:对照组(n = 18)自由喂食,进行产蛋暂停(n = 18),并在产蛋暂停期间每天注射 200μg/kg BW 的鸡 GH(chGH;n = 18)。在实验的第 6 天(卵巢退化)、第 13 天(卵巢恢复)和第 17 天或第 20 天(卵巢恢复),从每组母鸡中分离肝脏、卵巢基质和卵泡。结果表明,在禁食期间注射 chGH(1)增加了<1mm 的卵泡数量和这些卵泡中增殖细胞核抗原(PCNA)阳性(增殖)细胞的数量;(2)减弱了白色卵泡中 PCNA 和生存素 mRNA 的表达以及基质和白色卵泡中半胱天冬酶 3、8 和 9 的活性;(3)加剧了黄色分级卵泡的闭锁;(4)随着肝 IGF-1 转录水平的显著增加,同时加深了饥饿对卵黄基因表达的影响(P < 0.05 至 P < 0.001)。延长 chGH 在重新喂食期的注射对检查参数没有明显影响。总之,这些结果提供了证据表明,GH 通过调节细胞增殖和凋亡,促进母鸡产蛋暂停期间前分级卵泡的形成和发育。chGH 处理后卵巢卵泡中细胞增殖和凋亡相关基因表达或酶活性的改变以及肝中卵黄蛋白的表达强烈表明,这种激素参与决定鸡卵巢在产蛋暂停期间的退化和恢复速度。