Effects of Ammonia Concentration on Sperm Vitality, Motility Rates, and Morphology in Three Marine Bivalve Species: A Comparative Study of the Noble Scallop Mimachlamys nobilis, Chinese Pearl Oyster Pinctada fucata martensii, and Small Rock Oyster Saccostrea mordax.

Ammonium (NH4+) plays a crucial role in the reproductive processes of key biotic groups in aquatic ecosystems-bivalves. This study aims to elucidate the effects of three different ammonium ion concentrations on sperm vitality, swimming kinematics, and morphology of Mimachlamys nobilis, Pinctada fucata martensii, and Saccostrea mordax. The results indicate that the sperm vitality and motility rates of M.nobilis and S. mordax are inversely proportional to the ammonium concentration, especially in the treatment group with an ammonium concentration of 3 mmol/L, where the decrease in sperm vitality and motility is most significant. In contrast, the sperm of P. fucata martensii reacted differently to increasing ammonium concentrations. After the addition of 2 mmol/L of ammonium, the sperm vitality and motility of P. fucata martensii reached a peak, showing a significant stimulatory effect. Additionally, as the ammonium concentration increased, the curling of the sperm flagella in M.nobilis and S. mordax increased. However, sperm flagella curling in P. fucata martensii showed no change compared to the control group. This study provides insights into the effects of ammonium concentrations on the sperm vitality and motility of three marine bivalve species and highlights the importance of sperm flagella curling as a factor affecting sperm.

Protective role of antifreeze proteins on sterlet (Acipenser ruthenus) sperm during cryopreservation.

The loss of sperm quality in sterlet (Acipenser ruthenus) due to freeze-thaw process in cryopreservation was investigated in the present study. Two antifreeze proteins (AFPI or AFPIII) were used at different concentrations of 0.1, 1, 10, and 100 µg/mL. We compared motility, curvilinear velocity, and plasma membrane integrity of fresh, cryopreserved sperm, and sperm cryopreserved in the presence of antifreeze proteins. Fresh sperm (control) had 85 ± 4% motility and 160 ± 2 µm/s curvilinear velocity, respectively. After cryopreservation, the motility of frozen-thawed sperm without addition of antifreeze proteins significantly decreased (44 ± 9%), compared to the control. The highest motility of frozen-thawed sperm was obtained in cryopreserved sperm with addition of 1 µg/mL of AFPIII (58 ± 14%). No significant differences were observed in curvilinear velocity between fresh sperm and cryopreserved sperm with/without addition of AFPI or AFPIII. The flow cytometry analysis revealed that fresh sperm contained 94.5 ± 6% live cells, while the cryopreserved sperm only contained 26.6 ± 14% live cells. Supplementation of antifreeze proteins has significantly improved the percentage of live cells in frozen-thawed sperm, except 0.1 µg/ml of AFPI group. No significant difference in percentage of live cells was detected in the sperm cryopreserved with 10 µg/mL of AFPI or AFPIII, compared to fresh sperm. Thus, addition of antifreeze proteins to cryopreservation medium could be considered to improve the post-thawed sperm quality of sterlet.

Cryopreservation of very low numbers of spermatozoa from male patients undergoing infertility treatment using agarose capsules.

This study tried to cryopreserve low numbers of spermatozoa from men undergoing infertility treatments by inserting into agarose capsules. The capsules were transferred into a drop of cryoprotectant solution and injected 3-4 motile spermatozoa that were selected by the swim-up method by conventional intracytoplasmic sperm injection. These capsules were put on a Cryotop® and frozen in liquid nitrogen vapor, and then submerged into liquid nitrogen and subsequently thawed and recovered. The motile spermatozoa in the capsules were counted. Eventually, we cryopreserved 2142 motile spermatozoa in 702 agarose capsules from 26 male patients and 1356 (63%) spermatozoa maintained their motility after thawing. The spermatozoa motility rates after thawing (MRAT) ranged from 20.0% (5/25) to 95.1% (58/61) among patients. The median MRAT was 68.3% (interquartile range 46.1-75.7). The total number of motile spermatozoa collected by swim-up method strongly correlated with MRAT (r = 0.746). It was possible to cryopreserve spermatozoa from male patients undergoing infertility treatment using agarose capsules. However, there were wide differences in MRAT among patients. It seems the spermatozoa from semen where there were many motile spermatozoa may have higher freezing resistance. Further studies using this method in cryptozoospermic semen, testicular and epididymal spermatozoa are required.

Semen characteristics of the amazonian jundiá (Leiarius marmoratus Gill, 1870) / Característica seminal de jundiá amazônico (Leiarius marmoratus Gill, 1870)

The study evaluated qualitative and quantitative characteristics of Amazonian jundiá semen. The experiment was carried out in February 2015 at Cia do Peixe, a company located in Goiás state, Brazil, that specialises in fish fry production. Three male L. marmoratus farmed in dugout ponds, weighing 1.34 ± 0.29 kg and measuring 39.33 ± 1.15 cm in length, were tested. The specimens were captured and transferred to a 1000-L tank at the Reproduction Laboratory of the abovementioned company. Water temperature was measured at 7:00 a.m. and 5:00 p.m., and the fish were fed twice daily. For semen collection, the fish were captured from the tank using a dip net and constrained with a wet cotton towel. Their eyes were covered and their urogenital papilla was cleaned and dried with paper towel. Semen was collected in microcentrifuge tubes that were immersed in ice and analysed immediately. On average, the sperm motility rate was 83.33%, motility duration was 5.33 min, sperm concentration was 1,795,833 cells/ mm3, and vigour was 4. The morphological analysis of the sperm revealed tail anomalies in 17.66%, midpiece anomalies in 20%, and head anomalies in 5.33%. Based on qualitative and quantitative characteristics, L. marmoratus semen was shown to be suitable for use in artificial reproduction procedures.

Objetivou-se avaliar qualitativamente e quantitativamente as características seminais do Jundiá Amazônico. O experimento foi realizado em fevereiro de 2015, a Cia do Peixe, uma empresa localizada no Estado de Goiás, Brasil, especializada em produção de alevino. Três masculino L. marmoratus cultivados em tanques de esconderijo subterrâneo, pesando 1,34 ± 0,29 kg e medindo 39.33 ± 1,15 centímetros de comprimento, foram testados. Os espécimes foram capturados e transportado para um tanque de 1000 L no Laboratório da empresa acima indicado reprodução. A temperatura da água foi medida a 07:00 e 17:00 e os peixes foram alimentados duas vezes ao dia. Para a coleta de sêmen, os peixes foram capturados a partir do tanque usando uma rede de mergulho e constrangidos com uma toalha de algodão molhado. Seus olhos estavam cobertos e sua papila urogenital foi limpo e seco com toalha de papel. O sémen foi recolhido em tubos de microcentrífuga que foram imersas em gelo e analisadas imediatamente. A taxa de motilidade média foi 83,33%, a duração de motilidade média foi 5,33 minutos, concentração espermática foi de 1.795.833 celulas/ mm3 e o vigor 4. A análise morfológica revelou 17,66% de defeitos de cauda, 20% de defeitos de peça intermediária e 5,33% de defeitos de cabeça. O Jundiá da Amazônia (Leiarius marmoratus Gill, 1870) apresenta característica seminais e espermáticas quantitativas e qualitativas que permitem sua utilização em técnicas de reprodução artificial.

Long-term effects of silver nanoparticles on reproductive activity of rabbit buck.

Using the rabbit as an animal model, this study evaluated the long-term effect of silver nanoparticles (NPs) administered intravenously (0.6 mg/kg bw) on reproductive activity and sperm quality. Semen analysis was performed by optical microscopy and sperm motility evaluation by computer assisted sperm analyzer (CASA). Mitochondria oxygen consumption, light and transmission electron microscopy of rabbit testis and ejaculated sperm were also carried out. Throughout the experiment NP-treated rabbits showed higher seminal reactive oxygen species (ROS), less motile sperm, and lower curvilinear velocity and oxygen consumption than control animals. In contrast, libido, serum testosterone, sperm concentration, and semen volume were hardly affected by NPs. Transmission electron microscopy analysis did not show any evident morphological damage in testes; however, Ag NPs are visible in spermatids and ejaculated sperm. These preliminary results show that Ag NPs can reach the testes, compromising sperm motility, sperm speed, and acrosome and mitochondria shape and function.