Effect of Methyl Farnesoate Administration on Ovarian Growth and Maturation in the Freshwater Crab Travancoriana schirnerae

Abstract

This study assessed the effect of exogenous administration of methyl farnesoate on growth and maturation of ovary in the freshwater crab Travancoriana schirnerae. Results provide strong evidence that methyl farnesoate administration induced ovarian growth in all phases of oogenesis as judged by the increased ovarian indices, oocyte diameter and oocyte proportion values of experimentals over controls. Our observations also revealed that methyl farnesoate treatment induced avitellogenic and previtellogenic ovaries to grow into vitellogenic and early vitellogenic to middle vitellogenic ovaries as evidenced by the presence of a large number of vitellogenic oocytes in avitellogenic and previtellogenic ovaries and enhanced yolk deposition in early vitellogenic ovaries. However, methyl farnesoate injection during late vitellogenic phase effected no significant change in morphology or histology of the ovary. From the results it is evident that methyl farnesoate administration caused a marked increase in gonial proliferation in both reproductive and non-reproductive phases. The elevated ovarian index, mean oocyte diameter and oocyte proportion values of experimentals over controls in the present investigation may be attributed to the increased growth and yolk deposition in oocytes triggered by methyl farnesoate. It is concluded that methyl farnesoate administration is effective in inducing ovarian growth and maturation thereby reducing the duration of the ovarian cycle which is highly advantageous for a species of aquaculture potential.

Effects of methyl farnesoate injection on spermatozoa number and reproductive indices in the narrow-clawed crayfish Pontastacus leptodactylus

“…Nauplius, 30: e2022006 reproductive system. The results of this study are consistent with the results of other studies on other decapod species (Nagaraju et al, 2004;Alfaro et al, 2008;Raghavan and Ayanath, 2018). Further research should be carried out to determine the effect of MF injection on reproductive endocrine metabolism, gamete composition (e.g., protein and lipid profiles) and histology of different regions of the vas deference to assess changes in quantities and ratios of cell types in male reproductive tracts in crayfish.…”

“…MF is included in several hormonal processes in crustaceans. There are studies showing that MF induces gonadal development in some decapods (Alfaro et al, 2008;Marsden et al, 2008;Nagaraju and Borst, 2008;Zaleski and Tamone, 2014;Hemalatha et al, 2016;Raghavan and Ayanath, 2018). For example, gonadal development of decapods induced by MF has been reported in the estuarine female crab Neohelice granulata (Dana, 1851) (see Medesani et al, 2015) and freshwater crab Oziothelphusa senex senex (Fabricus, 1798) (see Reddy and Reddy, 2015) and Alfaro et al (2008) found that MF has an effect on spermatophore quality in the white shrimp, Litopenaeus vannamei (Boone, 1931).…”

Insights on Molecular Mechanisms of Ovarian Development in Decapod Crustacea: Focus on Vitellogenesis-Stimulating Factors and Pathways

“…In contrast, MF levels did not change with maturation in M. rosenbergii , but were correlated with molting ( 129 ) and MF was also demonstrated to inhibit late ovarian stage development with reduced fecundity levels in P. monodon ( 130 ). MF injection during the late vitellogenic phase had no significant effect on post-vitellogenesis or spawning in the freshwater crab Travancoriana schirnerae ( 131 ). Nevertheless, dietary inclusion of MF stimulated vitellogenesis in the crayfish P. clarkii and P. monodon , bringing about increased oocyte diameter, higher fecundity and egg fertility, and increased hatching rates ( 123 , 132 ).…”

Effect of Exogenously Administered Methyl Farnesoate and 20-OH Ecdysone on Polypeptide Profile of Vitellogenin and Vitellin in the Freshwater Crab Travancoriana schirnerae

“…In addition to the important roles played in the regulation of moulting, larval development and morphogenesis (Abdu et al, 1998;Reddy et al, 2004), MF, the crustacean equivalent of the juvenile hormone III of insects, functioned as a gonadotropin. The gonadotropic effect of MF and farnesoic acid (precursor to MF) has been reported in a number of crustaceans (Rodriguez et al, 2002;Mak et al, 2005;Tiu et al, 2006;Balasubramanian et al, 2010;Reddy and Reddy, 2015;Hemalatha et al, 2016;Sudha Devi and Aswani, 2018;Muhd-Farouk et al, 2019). In vitro studies by Otsu (1963) reported that MF promoted the development of oocyte and Vg messenger in the hepatopancreas and ovary.…”