Transcriptome Analysis During Follicle Development in Turkey Hens With Low and High Egg Production

Abstract

Low and high egg producing hens exhibit gene expression differences related to ovarian steroidogenesis. High egg producing hens display increased expression of genes involved in progesterone and estradiol production, in the granulosa layer of the largest follicle (F1G) and small white follicles (SWF), respectively, whereas low egg producing hens display increased expression of genes related to progesterone and androgen production in the granulosa (F5G) and theca interna layer (F5I) of the fifth largest follicle, respectively. Transcriptome analysis was performed on F1G, F5G, F5I, and SWF samples from low and high egg producing hens to identify novel regulators of ovarian steroidogenesis. In total, 12,221 differentially expressed genes (DEGs) were identified between low and high egg producing hens across the four cell types examined. Pathway analysis implied differential regulation of the hypothalamo-pituitary-thyroid (HPT) axis, particularly thyroid hormone transporters and thyroid hormone receptors, and of estradiol signaling in low and high egg producing hens. The HPT axis showed up-regulation in high egg producing hens in less mature follicles but up-regulation in low egg producing hens in more mature follicles. Estradiol signaling exclusively exhibited up-regulation in high egg producing hens. Treatment of SWF cells from low and high egg producing hens with thyroid hormone in vitro decreased estradiol production in cells from high egg producing hens to the levels seen in cells from low egg producing hens, whereas thyroid hormone treatment did not impact estradiol production in cells from low egg producing hens. Transcriptome analysis of the major cell types involved in steroidogenesis inferred the involvement of the HPT axis and estradiol signaling in the regulation of differential steroid hormone production seen among hens with different egg production levels.

Transcriptomic diversification of granulosa cells during follicular development between White Leghorn and Silky Fowl hens

“…We found that genes associated with steroidogenesis were upregulated in phGC of WL hens, whereas genes related to androgen production were upregulated in SF. These results are consistent with those of previous studies on high- and low-yielding hens ( Brady et al, 2021 ). Among the genes upregulated in WL, ADIPOQ can stimulate progesterone secretion by regulating key steroidogenesis genes ( STAR , CYP11A1 , FSHR , and LHR ) ( Li et al, 2021 ).…”

“…The difference in the number of dominant follicles leads to a decrease in the po fc number and disruption of developmental continuity. The number of po fc directly affects the continuity of ovulation ( Brady et al, 2021 ), and the continuity of follicular development determines the egg-laying performance in chickens ( Evans, 2003 ). We found that the po fc in WL had six grades (F1‒F6), whereas follicles in SF mostly had four grades (F1‒F4).…”

Transcriptome comparative analysis of ovarian follicles reveals the key genes and signaling pathways implicated in hen egg production

“…Ren showed seven key DEGs, including EPOX , StAR , CYP17 , 3β-HSD , CYP1B1 , CYP19A1 , and SR-B1 , were related to Peking duck ovarian follicle development [ 21 ]. Moreover, transcriptome analysis of the granulosa layer of the largest follicle (F1) and fifth largest follicle (F5), theca interna layer of F5 follicle, and small white follicle samples from low and high egg producing turkey hens revealed 12,221 DEGs were identified, and among them, several of the most promising candidates and signaling pathways may be mainly involved in differential regulation of the hypothalamo-pituitary-thyroid axis, particularly thyroid hormone transporters and thyroid hormone receptors, and of estradiol signaling [ 22 ]. However, the pivotal genes and signaling pathways controlling the development of various-sized ovarian follicles in chicken, and their exact physiological roles and regulatory mechanisms in egg production remain largely unclear yet.…”

Comparative Transcriptome Analysis Provides Novel Insights into the Effect of Lipid Metabolism on Laying of Geese

“…Lipids are not only important precursors of steroid hormones but are also important components of cell membranes. Steroid hormones play a crucial role in both the initiation of egg production and the level of egg production [ 38 , 39 ]. Meanwhile, cell adhesion plays an important role in the selection and development of poultry follicles [ 40 ].…”