Effects of cold seawater pre-treatments on induction of early sexual maturation and sperm production in European eel (Anguilla anguilla).

To induce sexual maturation in captivity, eels rely on hormonal treatments, but this process is costly and time-consuming. As an alternative, different types of conditioning, also referred as pre-treatment, have been assessed to ease hormonal treatment response. Recent studies have shown that migrating eels experience a wide range of temperatures, varying from 12 °C at night to as low as to 8 °C during the day.

Characterization of potential spermatogonia biomarker genes in the European eel (Anguilla anguilla).

Identification of specific molecular markers for spermatogonial stem cells in teleost is crucial for enhancing the efficacy of reproductive biotechnologies in aquaculture, such as transplantation and surrogate production in fishes. Since it is not yet possible to distinguish spermatogonial stem cells of European eel (Anguilla anguilla) using specific molecular markers, we isolated spermatogonial cells from immature European eels to find these potential markers. We attempted this by studying three candidate genes: vasa, nanos2, and dnd1.

Effect of seawater temperature and pH on the sperm motility of the European eel.

The current climate change situation could bring critical effects for marine species, especially those already considered endangered. Although some species can adapt fast to the environmental changes, it is necessary to get into the worst scenario and develop tools to anticipatedly assess the physiological effects of such environmental change. With this purpose, our study aims to determine the effect of a range of seawater temperatures and pHs on sperm motility in the European eel (Anguilla anguilla).

Superoxidase dismutases (SODs) in the European eel: Gene characterization, expression response to temperature combined with hormonal maturation and possible migratory implications.

Superoxide dismutases (SODs) are antioxidant enzymes that protect cells from oxidation. Three SODs have been identified in mammals, but there is limited information in teleosts. This study investigates SODs in the European eel and their expression patterns during testis maturation.

Successful cryopreservation in biodegradable containers of sperm from aquaculture Mediterranean fishes.

We aimed to evaluate the efficiency of hard-gelatin and hard-hydroxypropyl methylcellulose (HPMC) capsules as biodegradable alternative containers to plastic straws in European eel (Anguilla anguilla), gilthead seabream (Sparus aurata) and European sea bass (Dicentrarchus labrax) sperm cryopreservation. Sperm samples from each European eel (n = 12) were diluted 1:8:1 (sperm: extender P1+5 % egg yolk: methanol). Gilthead seabream (n = 12) samples were individually diluted in a cryoprotectant solution of 5 % MeSO + NaCl 1 % plus BSA (10 mg mL) at a ratio of 1:6 (sperm: cryoprotectant solution).