Gonadal development and steroid hormone profile of wild caught grey mullet (Mugil cephalus)

Abstract

The grey mullet Mugil cephalus is one of the popular and fast growing fishes being cultured in tropical and subtropical regions. In the present study, histological observation of gonadal development and corresponding changes in sex steroid levels from different maturity stages of wild caught male and female were studied. In female, testosterone and 17β-estradiol increased with the advancement of maturation and reached peak (17β-estradiol, 323 ± 13 pg/ml; testosterone, 938 ± 7.87 pg/ml) in mature stage, whereas the level of progesterone was maximum (488 ± 4.9 pg/ml) during ripe stage. Vitellogenin level in serum showed a similar trend as 17β-estradiol. In case of male, the testosterone level in serum increased gradually with advancement of maturation and was maximum (1820 ± 40.25 pg/ml) during ripe stage, whereas significant decrease in 17β-estradiol and progesterone was noticed with advancement of maturation. The fundamental information from this investigation would be useful for developing protocol for accelerating maturation and spawning under captive condition.

Transcriptomic analyses of gastrointestinal function in the "dwarf" and "medium" forms of Sthenoteuthis oualaniensis during sexual maturation

“…Interestingly, of these five pathways, steroid hormone biosynthesis (ko00140) and alpha-Linolenic acid metabolism (ko00592) have a close relationship with oocyte development and sexual maturity [ 18 , 19 ]. Steroid hormones (e.g., 17β-estradiol, progesterone) can accelerate the maturation process in grey mullet fish through regulation of exogenous hormones in captivity [ 18 ]. In humans, 17β-estradiol and progesterone are responsible for controlling the female sexual cycle [ 20 ].…”

Stimulation of gonad maturation in mullet fish Mugil dussumieri using MT, E2, hCG, and Ovaprim hormone

“…According to Hefny et al (2016) testosterone hormone level was ranged from 29750 ± 4922 pg/ ml to 2690 ± 2807 pg/ml with the lowest 17400 ± 1054 pg/ml and the highest 30500 ± 2037 pg/ ml. According to Kumar et al (2015) 938 ± 7.87 pg/ml while according to Yelghi et al (2012) 11 pg/ml, 70 pg/ml and 370 pg/ml. According to Reading and Sullivan (2017) increased testosterone hormone level can be affected by FSH which acts on the theca cell layer as the main regulator of estradiol production.…”

“…Estradiol hormone level in the treatment and control increased from day 0 to day 60 with the highest increased in control. According to Hefny et al (2016) estradiol hormone level was 199 ± 87 pg/ml and 102 ± 16 pg/ml, Kumar et al (2015) 323 ± 13 pg/ml, Chang et al (1995) 547.3 ± 19.3 pg/ml, 533.1 ± 54.1 pg/ml and 1354.1 ± 297.0 pg/ml and Yelghi et al (2012) 1800-3600 pg/ ml. Increased estradiol hormone level result in stimulation of vitellogenesis which accelerates gonad development (Zahri et al 2018;Sinjai et al, 2014).…”

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“…When vitellogenesis is complete, oocytes become larger cells, of about 1 mm (in tropical species), which contain all the information of maternal mRNAs, proteins, lipids, carbohydrates, vitamins, and hormones necessary for the embryo's development (LUBZENS et al, 2010). Full vitellogenic oocytes remain dormant in the ovaries during the spawning season (QUAGIO- GRASSIOTTO et al, 2013) and are responsible for hormonal induction in this period (BUGEL et al, 2011;KUMAR et al, 2015). In this context, similar densities occupied by vitellogenic oocytes between days 0, 6, 16 and 30 ( Figure 4D) suggest that females remained mature and could theoretically be induced at any time over this period.…”