Recombinant vs purified mammal gonadotropins as maturation hormonal treatments of European eel males

Using Osmotic Pumps to Induce the Production of Gametes in Male and Female European Eels

“…However, the sperm volumes produced by these males were significantly lower compared to the control group. The results of control group were similar to those obtained by Herranz-Jusdado et al [10], since, in both studies the males started to produce sperm in the 6th week of the treatment and with similar volumes and densities throughout the weeks of experiment. Additionally, the low-density values of the OP-100 and OP-200 groups were not enough to make up for the low volume values.…”

“…Regarding male European eels, human chorionic gonadotropin (hCG) has been the most widely used hormone for reaching spermiation, but it has been administered to the animals in different formats [7,8]. Currently, the use of weekly injections of recombinant human chorionic gonadotropin (hCG rec ) is considered an effective alternative and showed better results than hCG in terms of sperm quantity and quality [9,10].…”

Development of innovative methods for induction of European eel (Anguilla anguilla) spermatogenesis

“…E.g. European eels appear to show greater individual viability and a slower response to the hormonal treatment (Palstra et al 2005;Pérez et al 2009;Herranz-Jusdado et al 2019). Furthermore, Japanese eel males appear to be more sexually advanced at the start of migration (Boëtius and Boëtius 1967).…”

“…This achievement may not be far away as European eel larvae production has steadily improved over the years and the first successful exogenous feeding of European eel larvae has been achieved (Butts et al 2016). The current state-ofthe-art of European eel maturation involves a weekly intraperitoneal injection of recombinant hCG for the males (Asturiano et al 2005(Asturiano et al , 2006Gallego et al 2012;Herranz-Jusdado et al 2019). For females, weekly intraperitoneal injections of CPE or SPE are used, followed by a CPE or SPE primer when a significant weight increase is observed and oocytes biopsies show the appropriate oocyte stage (determined by lipid droplet size).…”

“…In particular, under the assumption that Sertoli cells control spermatogonial proliferation (Schulz et al 2010), and that Sertoli cells do not express Lhr (García-López et al 2009), the additional assumption of the activation of Fshr by high concentrations of Lh is crucial for the above hypotheses. However, hCG is capable of inducing full spermiation as well (Asturiano et al 2005(Asturiano et al , 2006Gallego et al 2012;Herranz-Jusdado et al 2019), but hCG does probably not activate Fshr like Lh, even at high concentrations (Bogerd et al 2001;Laan et al 2002;Kwok et al 2005). Although hCG has been shown to affect eel pituitary gonadotropin production (Peñaranda et al 2010b), the effect of hCG is unlikely to be a result of pituitary Lh release, since the effect of hCG is also seen in hypophysectomised eels (Boëtius and Boëtius 1967;Khan et al 1987).…”