Ultrastructure and melatonin 1a receptor distribution in the ovaries of African ostrich chicks

Abstract

Healthy 90-day-old ostrich chicks were used in the present study. The ultrastructure and melatonin 1a receptor (MT1) distribution in the ovaries of ostrich chicks was observed by transmission electron microscope and light microscope. The results showed that the ostrich chick ovary contained primordial follicles, primary follicles and secondary follicles, but no mature follicles. There are some unique ultrastructural characteristics observed in the secondary follicle, such as the cortical granule, which was located in cytoplasm beside the nucleus and appeared first in the oocyte. The zona radiata appeared in the secondary follicle, and there was an obvious vitelline membrane. There were intraovarian rete, connecting rete, and extraovarian rete in the ovaries of ostrich chicks. This is the first study that provides immunohistochemical evidence for the localization of the melatonin MT1 in the ostrich chick ovary. The germinal epithelium, follicular cell layer of every grade of follicle, cytoplasm of the oocyte and interstitial cells all expressed MT1. The expression of positive immunoreactivity materials was the strongest in the follicular cell layer of the primordial follicle and germinal epithelium, was weaker in the follicular cell layer of the primary follicle and secondary follicle, and was weakest in the oocytes of all grades of follicle. In addition, the extraovarian rete displayed strong positive expression of MT1, while there was no positive expression in the intraovarian rete or connecting rete. The positive expression of MT1 immunoreactivity in the ovary was very strong, implying that the ovary is an important organ for synthesizing MT1.

Melatonin Induced Changes in Specific Growth Rate, Gonadal Maturity, Lipid and Protein Production in Nile Tilapia Oreochromis niloticus (Linnaeus 1758)

“…The antigonadal effects of melatonin has also been reported in Oryzias latipes ( Uraski, 1972 ), and Heteropneustes fossilis ( Sundararaj and Keshavanath, 1976 ). The effect of MLT on the structure of ovary and ovarian cells was similar as reported earlier ( Borg and Ekstrom, 1981 ; Fatemet et al, 2007 ; Wang et al, 2008 ). The minimum employed dose of melatonin was 25 μg/100 g body weight/day, and this is frequently reported dose to study the effect of melatonin on the gonads ( Maitra et al, 2005 ).…”

Research Article Association of polymorphisms of physiological candidate genes with phenotype and estimated breeding values of reproductive and growth traits in Thai indigenous chickens

“…Melatonin regulates ovarian function through activation of multiple receptors and signaling pathways on different target cell types especially theca and granulosa cells (Wang et al, 2008). The binding site in the chicken ovary is located in the follicular cell layer (Ayre et al, 1992).…”

The effect of SNP rs400827589 in exon 2 of the MTNR1B gene on reproductive seasonality and litter size in sheep

“…However, there were few studies about the polymorphism of MTNRIB . Interestingly, some studies in birds found that melatonin receptor subtypes were identified in ovaries (He et al., 2014; Sundaresan et al., 2009; Wang et al., 2008), which indicated that melatonin may directly affect ovarian function through activating of its receptors. For example, the expression levels of MTNR1A, MTNR1B and MTNR1C initially increased and later decreased during the follicular development cycle in geese, suggested that melatonin receptors participated in activating small follicles to develop into subsequent higher hierarchical follicles (He et al., 2014).…”