A Novel Approach for Induced Out-of-season Spawning of Eurasian Perch, Perca fluviatilis

International audienceIn this study, the systematic development of a protocol allowing an effective advanced spawning of wild Eurasian perch with the use of salmon gonadoliberin analogue (sGnRHa) was undertaken. The novel approach used in this study involved the application of a strategy of the repeated administration of sGnRHa (i.e., the hormone was given in two doses: priming and resolving) along with an additional thermal stimulation of ovulation. Additionally, the developed protocol was tested for its suitability in the controlled reproduction of domesticated broodstock. The obtained results suggested that the best interval between the hormonal treatments is 7 days when a water temperature of 10°C is kept constant between the two injections and when the resolving injection is followed by rapid increments of temperature up to 12°C, at which spawning is expected. This study revealed that the most suitable priming dose of sGnRHa was 10 µg kg-1 , at which the highest embryonic survival rates (>80%) an

Proteomic analysis of pikeperch seminal plasma provides novel insight into the testicular development of domesticated fish stocks

Control of the reproduction of domesticated stocks is considered a prerequisite for aquaculture development of pikeperch. However, knowledge about the physiology of the captive pikeperch male reproductive system and the biology of semen is very limited, especially regarding protein characteristics. The aims of our study were to characterize pikeperch sperm quantity and quality parameters and to analyze changes in the proteome of the same males spawned for the first and second times. Moreover, attempts were made to generate the first proteomic library of seminal plasma proteins. Semen collected during the first spawning season were was characterized by lower sperm concentration and volume than for the second season. Using mass spectrometry-based label-free quantitative proteomics, we identified 850 proteins in the seminal plasma of pikeperch from both spawning seasons, and 65 seminal proteins were found to be differentially abundant between the first and second spawning seasons. The majority of differentially abundant proteins were involved in stress and immune responses, developmental processes, cofactor metabolic processes, proteolysis, cellular oxidant detoxification and organization of the extracellular matrix (ECM). In addition, several proteins unique to pikeperch seminal plasma were identified, including antifreeze proteins, hibernation-specific plasma proteins, lectins and vitellogenin. In summary, our results indicate that males that spawned for the first time were characterized by incompletely mature gonads and the expression of proteins associated with the early phase of spermatogenesis and ECM organization. On the other hand, males that spawned for the second time exhibited advanced gonadal maturation and expression of proteins related to the late stage of spermatogenesis and sperm maturation, including regulation of reactive oxygen species generation, bicarbonate production, sperm elongation and separation. The identification of a large number of seminal plasma proteins provides a valuable resource for understanding the functions of seminal plasma and the molecular mechanisms involved in testicular development and maturation in domesticated fish, which is a prerequisite for better control of reproduction in captivity

Optimalisation of the Activation Medium and Effect of Inhibiting Activities of Acid Phosphatase, Lactate Dehydrogenase and β-N-Acetylglucosaminidase on the Fertilisation Success of Eurasian Perch (Perca fluviatilis L.)

Although methods for the artificial reproduction of perch have been developed, a lack of information remains regarding the enzymes present in its semen, as well as their role in the fertilisation process. In this study, we first select the optimal activating solution for perch fertilisation and then determine the inhibition effect of enzymes that have already been reported as present in the sperm of teleosts—acid phosphatase (AcP), lactic dehydrogenase (LDH) and β-N-acetylglucosaminidase (β-NAGase)—on the percentage of motile spermatozoa and fertilised eggs. Of the 8 studied activation media, a solution composed of 80 mM NaCl, 20 mM KCl, 10 mM Tris, with pH 8.0 and 206 mOsm/kg proved to be optimal for perch gametes. The addition of ammonium molybdate (AcP inhibitor) caused no significant reduction in the percentage of fertilised eggs. On the other hand, the addition of 0.25 mM gossypol (LDH inhibitor) and 0.125 M acetamide (β-N-acetylglucosaminidase inhibitor) significantly decreased the fertilisation percentage to 41.1% and 52.4%, respectively, in contrast to the control (89.9 %). Both LDH and β-NAGase thus seem to play a very important role in the perch fertilisation process

A Novel Approach for Induced Out-of-season Spawning of Eurasian Perch, Perca fluviatilis

International audienceIn this study, the systematic development of a protocol allowing an effective advanced spawning of wild Eurasian perch with the use of salmon gonadoliberin analogue (sGnRHa) was undertaken. The novel approach used in this study involved the application of a strategy of the repeated administration of sGnRHa (i.e., the hormone was given in two doses: priming and resolving) along with an additional thermal stimulation of ovulation. Additionally, the developed protocol was tested for its suitability in the controlled reproduction of domesticated broodstock. The obtained results suggested that the best interval between the hormonal treatments is 7 days when a water temperature of 10°C is kept constant between the two injections and when the resolving injection is followed by rapid increments of temperature up to 12°C, at which spawning is expected. This study revealed that the most suitable priming dose of sGnRHa was 10 µg kg-1 , at which the highest embryonic survival rates (>80%) an