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. ResumoO Prochilodus brevis é um peixe reofílico, importante componente do ecossistema fluvial e apreciado na culinária nordestina. No entanto, ações antrópicas têm ameaçado sua sobrevivência. Desta forma, surge, nos pesquisadores, o interesse no desenvolvimento de protocolos de conservação do material genético, como a criopreservação seminal. Logo, a deter...

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. ResumoO tambaqui (Colossoma macropomum) é uma espécie nativa de peixe de água doce de grande importância para aquicultura brasileira. Devido a isso, diversas técnicas têm sido desenvolvidas para aperfeiçoar a reprodução desta espécie em cativeiro, dentre elas a criopreservação de sêmen de peixe. Como uma forma de melhorar os protocolos de criopreservação, tem-se buscado utilizar soluções diluidoras e métodos de congelação adequados, proporcionando uma boa qualidade seminal pós-descongelação. Dessa forma, este estudo objetivou avaliar a eficiência de diferentes diluidores e métodos de congelação na criopreservação do sêmen de tambaqui (C. macropomum). As amostras de sêmen fresco foram diluídas em diferentes tratamentos (Glicose 5% + 10% Dimetilsufóxido -DMSO; Glicose 5% + 10% Metil glicol -MG; Beltsville Thawing Solution -BTS + 10% DMSO e BTS + 10% MG) na proporção 1:9 e congeladas em máquina de congelação programada e em Dry shipper. As amostras seminais foram descongeladas e avaliadas para vitalidade, morfologia e cinética espermát...

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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 postactivation. 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. Key words: Colossoma macropomum, Piaractus brachypomus, Prochilodus brevis, sperm class analyzer ResumoO objetivo do presente trabalho foi investigar o desempenho cinético (motilidade e velocidades espermáticas) de Prochilodus brevis (curimatã), Colossoma macropomum (tambaqui) e Piaractus brachypomus (pirapitinga) em diferentes tempos pós ativação. O sêmen de P. brevis, C. macropomum e P. brachypomus foi coletado após indução hormonal com extrato hipofisário de carpa. As amostras não contaminadas com sangue, fezes ou urina tiveram motilidade subjetiva, morfologia, osmolaridade e concentração analisadas. As amostras selecionadas foram analisadas com o Sperm Class Analyzer.

Currently, aquaculture has been growing due to factors such as increased fish consumption and production, population growth, higher family income and urbanization (Food and Agriculture Organization of the United Nations (FAO), 2019). Therefore, studies that focus on investigating the reproductive biology of fish have been intensified to develop species conservation and genetic improvement programmes (Denniston, Michelet, & Godke, 2000), as well as to enable an increase in aquaculture production and reduce pressure on natural stocks. Thus, species belonging to genus Prochilodus, like Prochilodus brevis, a rheophilic species native to Northeast Brazil, have shown increasing potential for use in Brazilian aquaculture (Peixe Br, 2019) to meet the great demand for fish, as they are among the most important species in both commercial and subsistence continental

Background: Seminal cryopreservation is a technique that optimizes aquacultural production, as it requires less breeding and enables reproduction outside of the breeding season. This technique also helps to preserve species, thus reducing the pressure on the natural stocks. Several studies have sought to develop freezing protocols that result in semen of a good quality. However, some studies do not evaluate the ability of frozen semen to produce viable larvae. Therefore, the aim of this study was to verify the fertilizing capacity of the frozen semen of Prochilodus brevis.Materials, Methods & Results: Semen from twenty adult males of the Brazilian bocachico was collected and evaluated to establish the total motility, curvilinear velocity, straight linear velocity, average path velocity, membrane integrity, pH, and concentration. Six pools were formed, each of which was diluted in a freezing medium containing 5% glucose with 10% dimethyl sulfoxide (DMSO) or 5% glucose with 10% methyl glycol (MG). The samples were loaded into 0.25 mL French straws, frozen in a dry shipper, and stored in a liquid nitrogen canister. The semen was then thawed and evaluated to establish the total motility, curvilinear velocity, straight linear velocity, average path velocity, and membrane integrity. For the fertilization test, four females were used. The oocytes from each female were divided into three batches and fertilized with either fresh or cryopreserved semen. The rates of fertilization, hatching, and larval survival were then measured. Data were expressed as the mean ± standard deviation and analyzed using SAS (2002). The frozen semen with glucose + DMSO was significantly higher (P < 0.001) than the frozen semen with glucose + MG, in all seminal quality parameters evaluated (63.95 ± 15.88% and 25.36 ± 3.53% for the motility, 36.38 ± 7.02 μm.s-1 and 20.45 ± 2.84 μm.s-1 for the curvilinear velocity, 19.26 ± 2.74 μm.s-1 and 3.03 ± 1.40 μm.s-1 for the straight linear velocity, 25.70 ± 6.51 μm.s-1 and 6.90 ± 1.12 μm.s-1 for the average path velocity, and 63.58 ± 6.95% and 35.58 ± 11.26% for the membrane integrity, respectively). MG were very close to zero and not statistically significant. Regarding these same parameters, there were no significant differences (P > 0.05) when the fresh semen was compared to the cryopreserved semen with glucose + DMSO (36.25 ± 2.5% and 29.16 ± 5.64% for the fertilization rate, 38.56 ± 11.23% and 29.33 ± 11.75% for the hatching rate, and 11.59 ± 5.16% and 7.63 ± 5.46% for the larval survival rate, respectively).Discussion: This is the first study of the artificial fertilization of Prochilodus brevis using cryopreserved semen. Seminal quality parameters are important for predicting the success of the cryopreservation technique, however, in vivo tests are essential to confirm such success. Thus, obtaining larvae is a major step towards the standardization of a cryopreservation protocol for a particular species. It is known that cryopreservation reduces the seminal quality but is a necessary process for the conservation of male gametes in the long term and, as shown in this study, good results can be obtained. In this study, the best results were obtained with the inclusion of DMSO in the freezing medium. This effect can be attributed to DMSO having a very low molecular weight, which decreases the formation of ice crystals. Considering the results obtained, we concluded that it is feasible to obtain larvae of the Brazilian bocachico using frozen semen in a 5% glucose solution with 10% DMSO.

SummaryProchilodus brevis is a rheophilic species with a threatened natural population that promotes studies aimed at optimizing reproduction in captivity. The correct quantity of inseminating dose and activating solution volume significantly improves fertilization rates, thereby increasing productivity in captivity. The objective of this study was to determine the proportion of sperm per oocyte and the ideal volume of activating solution to be used in the assisted fertilization of P. brevis. Gametes were collected and fertilization performed in two steps. In step 1, the ideal proportion of spermatozoa was determined based on the fertilization rate:oocyte by testing six doses of semen: D1 = 30 × 103, D2 = 150 × 103, D3 = 300 × 103, D4 = 3 × 106, D5 = 5 × 106, and D6 = 10 × 106. In step 2, the fertilization and hatching rates were evaluated using different volumes of activating solution (V1 – 25 ml, V2 – 50 ml, V3 – 75 ml,V4 – 100 ml, V5 – 125 ml, and V6 – 150 ml). A linear regression equation was estimated from steps 1 and 2. The Student–Newman–Keuls test was used to compare the means. In step 1, the percentage of fertilization increased linearly, reaching a plateau of 51.69%. In step 2, the best fertilization rates were obtained with an estimated ideal volume of 75.64 ml per 2 ml of oocytes. Therefore, the proportion of 928,410.29 sperm:oocyte, associated with the volume of 75.64 ml of water per 2 ml of oocytes, provided the maximum reproductive performance for P. brevis.

Water pollution is a significant problem worldwide, particularly in Brazil where the majority of urban populations rely on drinking water from surface water reservoirs. The accumulation of plastic debris, such as polycarbonate blends, in reservoirs and other waterways is a public health issue because of health and environmental concerns associated with their chemical degradation. A compound commonly found in plastics, 2,2-bis(4-hydroxyphenyl)propane (bisphenol-A; BPA), has become a serious environmental problem due to its release in water and its estrogen-like properties. This paper focuses on understanding the degradation process of two types of plastics containing BPA, polypropylene (PP) and poly(lactic acid) (PLA), in surface waters. The strength of the chemical binding of BPA to PP and PLA was examined using thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy. Release of BPA from both types of plastics was determined in surface water samples collected from the Billings Reservoir, the largest source of drinking water of Sao Paulo residents. The results show that BPA bound to PP-based plastics is released more rapidly into surface waters than that bound to PLA-based plastics.