Suchergebnisse

Prochilodus brevis is a migratory fish, an important component of its river ecosystem and an appreciated animal in northeastern cuisine. However, human activities have threatened its survival. Thus, researchers have become interested in developing genetic material storage protocols, such as seminal cryopreservation. Therefore, determination of the appropriate freezing media and thawing rate is a fundamental step toward the use of this biotechnology in the production of common curimatã and for reducing risks to the species' survival. As such, the aim of the current study was to evaluate the effect of different freezing media and thawing rates on the quality of cryopreserved semen from P. brevis. For this study, males received a single dose of pituitary extract of carp 18 hours before semen collection. The semen samples were diluted in 5% glucose + 10% methyl glycol (MG), 5% glucose + 10% dimethyl sulfoxide (DMSO), 0.9% NaCl + 10% methyl glycol, and 0.9% NaCl + 10% dimethyl sulfoxide, loaded into 0.25-mL straws and frozen in liquid nitrogen vapor. The semen from each treatment was thawed at three different thawing rates: 25 °C for 30 sec, 30 °C for 16 sec and 40 °C for 12 sec. Motility, vitality and morphology analyses were performed by computer-assisted sperm analysis (CASA). The characteristics of the fresh sperm mostly resembled those found in the literature. For the parameters analyzed, fresh sperm presented higher sperm quality in comparison to all treatments with cryopreserved sperm (p < 0.05), except for the characteristic of normal morphology, for which the sperm cryopreserved in glucose and MG did not differ statistically from the fresh sperm. For the cryopreserved semen, the greatest results of total motility and curvilinear velocity (VCL) were obtained using glucose and DMSO, regardless of the thawing rate employed. For the straight-line velocity (VSL) and average path velocity (VAP), DMSO showed the best results, regardless of the diluent and thawing rate. With regard to vitality, the highest values were achieved when DMSO and thawing rates of 30 °C for 16 sec or 40 °C for 12 sec were used. In the morphological analysis, the greatest percentage of normal sperm cells was obtained using thawing rates of 25 °C for 30 sec and 40 °C for 12 sec, regardless of the freezing media. Sperm quality was found to suffer interference from the freezing media, as well as from interaction between its components (diluent and cryoprotectant) and the thawing rate used. Under the methodological conditions employed, the use of 5% glucose + 10% DMSO and a thawing rate of 30 °C for 16 seconds or 40 °C for 12 seconds is recommended for P. brevis semen cryopreservation.

The objective of the current study was to observe the performance kinetics (motilities and velocities) of the spermatozoa from Prochilodus brevis (curimatã), Colossoma macropomum (tambaqui) and Piaractus brachypomus (pirapitinga) species in different times post-activation. The sperm of P. brevis, C. macropomum and P. brachypomus species were collected after hormonal induction with carp pituitary extract. The samples with not contamination with water, urine or feces had motility subjective, morphology, osmolality and concentration analyzed. The samples selected were analyzed with Sperm Class Analyzer. Spermatozoa motility and velocities were captured at 10, 30, 60 and 120 s post-activation. No significant differences in total motility of P. brevis spermatozoa were observed between 10 s and 30 s post-activation. However, significant reduction was observed in 60 s. This reduction was more accentuated after 120 s. The same pattern of spermatozoa motility decline happened for C. macropomum and P. brachypomus. Velocities also followed the same pattern for the three species. There was significant reduction in velocities after 30 s; this reduction was more significant after 60 s. There was no significance difference between 60 s and 120 s post-activation. Sperm of C. macropomum and P. brachypomus show satisfactory sperm quality up to 60 s after activation. On the other hand, sperm of P. brevis up to 120 s after activation. These findings show that the rate of sperm motility in different times post activation is change for each species tested.

O estudo teve como objetivo avaliar a adição de polissacarídeos sulfatados (PS) extraídos de duas espécies de macroalgas verdes, Ulva lactuca e Caulerpa racemosa, no meio criodiluidor do sêmen de Colossoma macropomum. Para isso, foram avaliadas quatro concentrações de PS (1,0; 2,0; 3,0 ou 4,0 mg mL-1), de cada macroalga. A coleta de sêmen foi realizada durante o mês de setembro, em Fortaleza, Ceará, Brasil. As amostras de sêmen fresco foram analisadas quanto aos parâmetros de motilidade total dos espermatozoides, velocidade curvilinear (VCL), velocidade em linha reta (VSL), velocidade média do trajeto (VAP), morfologia espermática, integridade de membrana e integridade de DNA. Em seguida, foram criopreservadas em meio de congelação contendo dimetilsulfóxido (DMSO) 10% + glicose 5%, e suplementadas com as diferentes concentrações de PS, tendo ainda um tratamento não suplementado como controle. Após 15 dias, foram descongeladas em banho-maria a 45 ºC por oito segundos, e as mesmas análises do sêmen fresco foram realizadas. Através da análise estatística, os resultados mostraram que não houveram diferenças significativas (p > 0,05) entre as diferentes concentrações de PS testadas para nenhum dos parâmetros avaliados. Já em relação ao controle, não houve diferença nas concentrações (p > 0,05) para a motilidade total, no entanto, para VCL, VSL e VAP, as concentrações de 3,0 e 4,0 mg mL-1 de U. lactuca foram prejudiciais (p < 0,05). O mesmo foi observado em 4,0 mg mL-1 de C. racemosa para VSL e VAP. Para a morfologia, 1,0 e 4,0 mg mL-1 de C. racemosa reduziram os espermatozoides normais (p < 0,05), enquanto para as demais concentrações não houve diferença (p > 0,05). Para todas as concentrações de ambas as macroalgas, a integridade de membrana plasmática foi mantida (p > 0,05). Quanto à integridade do DNA, apenas 4,0 mg mL-1 de U. lactuca foi inferior ao controle (p < 0,05), enquanto as demais concentrações mantiveram o número de espermatozoides com DNA íntegro (p > 0,05). De acordo com os resultados obtidos, concentrações mais elevadas de PS são prejudiciais aos espermatozoides de tambaqui no meio de congelação, enquanto concentrações mais baixas mantiveram parâmetros espermáticos. Estudos posteriores são indicados para melhor avaliar o potencial antioxidante destes polímeros no meio criodiluidor do sêmen de C. macropomum, bem como de outras espécies de peixes.

Tambaqui (Colossoma macropomum) is a native freshwater fish that is of great importance for Brazilian aquaculture. Because of this importance, several techniques have been developed to improve the reproduction of this species in captivity. One of these techniques is the cryopreservation of sperm. In an effort to increase the efficiency of cryopreservation protocols, researchers have tried to determine suitable diluting solutions and freezing methods, which will provide a better post-thaw sperm quality. Thus, this study aimed to evaluate the efficiency of different diluents and freezing methods for the cryopreservation of tambaqui (C. macropomum) sperm. Samples of fresh semen were diluted in different treatments (Glucose 5% + 10% Dimethyl sulfoxide – DMSO, Glucose 5% + 10% Methyl glycol – MG, BTS + 10% DMSO and BTS + 10% MG) at a 1:9 dilution rate and frozen in a programmed freezing machine and a dry shipper. The semen samples were thawed and evaluated for vitality, sperm morphology and kinetics. Cryopreserved semen with DMSO and using the programmed freezing machine provided a greater percentage of motile sperm (15.44 ± 1.04%) after thawing compared to the dry shipper (3.99 ± 0.55%), regardless of the diluent. Additionally, DMSO showed better sperm velocities than MG regardless of the freezing method and the extender employed. A higher percentage of living spermatozoa was observed when glucose (37.28 ± 1.32%) (regardless of the freezing method and cryoprotectant) and DMSO (37.98 ± 1.25%) was used in the programmed freezing machine. For morphology, a greater amount of normal spermatozoa (46.10 ± 1.82%) was observed when the semen was cryopreserved using a freezing machine programmed with DMSO as the cryoprotectant and Glucose or BTS (38.16 ± 1.9% and 39.26 ± 1.87%, respectively) as extenders. Therefore, we suggest the use of the DMSO (10%) cryoprotectant in association with the Glucose (5%) extended in the programmed freezing machine for cryopreservation of C. macropomum semen.

The study aimed to evaluate the in vitro antioxidant action of glycosaminoglycans (GAGs) from the skin of Oreochromis niloticus, and to determine their ideal concentration to supplement the sperm freezing medium of Prochilodus brevis. In experiment 1, the in vitro antioxidant properties of GAGs were verified through the analysis of DPPH, chelating ferrous ability, and total antioxidant capacity. In experiment 2, milt pools were formed, which were frozen in solution supplemented or not with different GAGs concentrations: 0 (control), 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, or 5.0 mg mL-1 (total of 10 treatments). The samples were evaluated for membrane integrity, DNA integrity, sperm morphology, and sperm kinetics. The results of experiment 1 showed that the GAGs exhibited, with the increase of the concentration, significant antioxidant action, for all the evaluated tests, mainly in the chelating ferrous ability. In experiment 2, it was observed that the increase of GAGs concentration decreased kinetic parameters (P < 0.05), however, the control and 0.5 mg mL-1 GAGs concentration showed similar results. For the other parameters (membrane integrity, DNA integrity, and sperm morphology), there was no decrease in results with the increase of GAGs concentration. In conclusion, GAGs extracted from O. niloticus skin have antioxidant action, and the concentration of 0.5 mg mL-1 was the most adequate to supplement the P. brevis sperm-freezing medium.