Gonadotropin-releasing hormone (GnRH) and a GnRH analog induce ovarian maturation in the giant freshwater prawn,Macrobrachium rosenbergii

Abstract

Gonadotropin-releasing hormone (GnRH) is a highly conserved peptide that plays a role in regulating reproduction in both vertebrates and invertebrates. The present study investigated the effects of lamprey (l)GnRH-I, lGnRH-III, octopus (oct)GnRH and buserelin, a GnRH analog (GnRHa), on ovarian maturation and spawning in the giant freshwater prawn, Macrobrachium rosenbergii. We demonstrated that the times for ovarian maturation in prawns treated with octGnRH (at 50 and 500 ng/g BW), lGnRH-I and lGnRH-III (at 500 ng/g BW), and GnRHa (at 1,000 ng/g BW) were significantly shorter (23.50 ± 2.12 and 22.50 ± 1.15, 25.50 ± 4.04 and 25.50± 4.03, and 26.67 ± 4.04 days) than the controls (40.0 ± 3.40 days). On day 22 post-treatment, the gonadosomatic index (GSI) values of the prawns treated with octGnRH (at 50 and 500 ng/g BW), lGnRH-I and lGnRH-III (at 500 ng/g BW), and GnRHa (at 1,000 ng/g BW) were significantly greater (2.50 ± 0.72 and 4.64 ± 0.95, 6.07 ± 1.29 and 8.90 ± 1.04, and 3.88 ± 1.34%) than the controls (0.45 ± 0.15%). Vitellin protein was first detected in the ovary on day 15 and had increased significantly by day 22 in prawns treated with GnRHs at 500 ng/g BW, while it was not detected in the controls. The prawns treated with the GnRHs and GnRHa showed similar numbers and percentages of spawned and fertilized eggs to those of the control group. These findings indicate that GnRH controls ovarian maturation and spawning in this prawn, as in other species.

Modulation of complex coordinated molecular signaling by 5HT and a cocktail of inhibitors leads to ovarian maturation of Penaeus monodon in captivity

“…Transcripts of calnexin ( CNX ), calmodulin ( CaM ), and calreticulin ( CALR ) were significantly overexpressed ( p < 0.05) in HCT‐treated shrimps when compared with ESA shrimps (Figure ). However, expressions of these genes were high in 5HT‐treated shrimps as compared with HCT‐treated shrimps, as 5HT tends to induce GnRH pathway by inducing synthesis of GnRH (A. Ngernsoungnern et al, ; P. Ngernsoungnern, Ngernsoungnern, Sobhon, & Sretarugsa, ; Uawisetwathana et al, ). Protein expression analysis of CaM and calmodulin kinase (CaMK) was significantly high in HCT‐treated shrimps and 5HT‐treated shrimps when compared with ESA shrimps and CT‐treated shrimps.…”

Existence and distribution of gonadotropin-releasing hormone-like peptides in the central nervous system and ovary of the Pacific white shrimp, Litopenaeus vannamei

“…In comparison with these two shrimp species, GnRH-like peptides in L. vannamei seem to be more widely spread. The main function of GnRH in these shrimps might also be in reproductive control, as treatments with octGnRH and lGnRH-III shorten the ovarian maturation period and oocyte development in P. monodon and in M. rosenbergii (Ngernsoungnern et al 2008b;Ngernsoungnern et al 2009). This function is highly conserved, because, in teleost fish, GnRH type I and III neurons have been reported to be derived from the olfactory lobe.…”

“…Octopus GnRH, lamprey GnRH-I, and lamprey GnRH-III can also induce ovarian maturation in the freshwater prawn (M. rosenbergii; Ngernsoungnern et al 2009). In addition, the existence and distribution of GnRH-like peptides in the central nervous system (CNS) and in reproductive tissues have been revealed by using immunohistochemistry in a number of invertebrates, including mollusks (A. californica; Pazos and Mathieu 1999;Tsai et al 2003; Haliotis asinina; Nuurai et al 2010b), tunicates (Ciona intestinalis; Tsutsui et al 1998;Di Fiore et al 2000), the black tiger shrimp (P. monodon; Ngernsoungnern et al 2008c;Ngernsoungnern et al 2008b), and the freshwater prawn (M. rosenbergii; Ngernsoungnern et al 2008a), and might be present in other crustaceans, including L. vannamei.…”

Reproductive and growth performances in female giant freshwater prawn following inhibition of gonadal maturation using dopamine and medroxyprogesterone hormone

“…It can be seen from Figure 4 that several oogonia cells were in the early stage and developed oocytes were spotted because of the cytoplasm development compared to the control treatment which the nucleus was fused. According to the gonad histology by Ngernsoungnern et al (2009), in the previtellogenis phase, oocyte was on the oval-shaped, nucleolus was surrounded by nucleus, and follicle cell was spotted. Compared to the vitellogenic phase, oocyte appeared bigger than the previtellogenic phase, nucleolus was surrounded by the nucleus as well, and there were fatty follicle cell surrounding the oocyte.…”