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Background: Prochilodus brevis is a rheophilic fish of economic and ecological importance. However, anthropic action has made its population vulnerable. Thus, the development of reproductive biotechnologies, such as seminal conservation, is necessary to subsidize their fish farming. However, seminal collections are often performed in places with few laboratory resources, demanding studies to determine the maximum time for which sperm can be cooled, as well as its process until frozen. Thus, the present study aimed to evaluate the influence of cooling time and the presence of dilution solutions on cryopreservation of P. brevis semen.Material, Methods & Results: After seminal collection, nine pools were formed and analyzed for seminal pH, concentration, membrane integrity, morphology and spermatic kinetics - motility, curvilinear velocity (VCL), average path velocity (VAP) and straight line velocity (VSL). After the analysis of the pools in natura (control 1), they were processed as follows: 1)- immediate freezing (control 2); 2)- cooling: undiluted, diluted in coconut water powder (ACP-104) or diluted in 5% glucose, followed by cooling at different times (6, 12, 24 or 48 h); 3)- Post-refrigeration freezing: the pools were diluted in their respective diluents and 10% dimethyl sulfoxide. After 15 days, the samples were thawed and analyzed for the aforementioned parameters. For the cooled and post-thawed semen, a completely randomized design with 2 (diluent × cooling time) and 3 (storage form × cooling time and storage form × diluent) factors, respectively, was utilized. ANOVA and Dunnett tests were applied to compare the means. In case of seminal cooling, there was no difference (P > 0.05) in sperm motility between control 1 and the undiluted and diluted treatments in ACP-104 for up to 24 h. After 48 h, only the VCL of the sample diluted in ACP-104 was similar (P > 0.05) to that of control 1. When comparing forms of storage (undiluted, diluted in ACP-104 or diluted in glucose) and cooling times, the undiluted samples and the samples diluted in ACP-104 were better (P < 0.05) for all the kinetics parameters analyzed, than those diluted in glucose after 24 h. After 48 h, the cooled semen diluted in ACP-104 presented greater (P < 0.05) motility than the other treated semen samples. The samples diluted in glucose for 48 h presented lower spermatic velocity (P < 0.05) than those subjected to other treatments. Regardless of the diluent used, the post-thawed semen and the cooled semen diluted for 6 h, presented higher sperm kinetic values (P < 0.05) than those of control 2 and other treated samples. Overall, the samples diluted in ACP-104 showed satisfactory results when cooled for up to 48 h or cooled for up to 6 h and frozen.Discussion: This is the first study that froze semen from P. brevis after cooling. Although glucose is a commonly used diluent during seminal freezing and has good post-thawing stability for this species, it is not recommended for cooling before seminal freezing, as prolonged exposure of spermatozoa to glucose may cause osmotic stress to sperm cells. Conversely, good results with ACP-104 might be because of its rich composition, mainly the presence of indole-3-acetic acid (IAA), an auxin with proven potential for seminal conservation of other species. Therefore, for fertilization trials, it is recommended to use ACP-104 as diluent for seminal cooling of P. brevis for up to 48 h or semen that has been frozen after cooling in ACP-104 for a maximum of 6 h.

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

Diante as dificuldades do trabalho home office gerado pela pandemia da COVID-19, principalmente considerando os docentes universitários, o presente trabalho objetivou investigar os aspectos ergonômicos e os impactos do distanciamento social vivenciados por tutores e professores formadores de cursos de graduação a distância de uma universidade cearense, em um contexto pandêmico. Trata-se de uma pesquisa descritiva de cunho qualitativo e quantitativo, com aplicação de questionário on-line constituído por 37 questões (objetivas/subjetivas). Participaram 146 indivíduos, dos quais 56,2% eram mulheres, com média etária de 41 anos. 54,1% relataram ritmo de trabalho acelerado, 37,7% apresentam desconforto físico e 34,9% desconforto emocional. 83,6% estão praticando o distanciamento social, 63,7% apresentaram alterações de sono, 65,8% têm consumido mais alimentos, 94,5% têm assumido mais obrigações domésticas/familiares, mesmo assim 48,6% mantiveram a produtividade. Por fim, espera-se assessorar os gestores na dinâmica das atividades de graduações a distância e permitir uma reflexão da prática educacional em tempos adversos.

Background: The addition of antioxidant substances to a cryoprotective solution can increase its protective capacity, shielding spermatozoa from the oxidative stress caused by the seminal cryopreservation process. However, there is no record of a seminal cryopreservation protocol of tambaqui (Colossoma macropomum) using antioxidants as a supplement to the cryoprotective solution. Thus, the objective of this study was to evaluate the effects of adding vitamin C, vitamin E, cysteine, and/or taurine to the seminal cryopreservation of tambaqui.Materials, Methods & Results: Pools of semen (n = 10) were diluted in cryoprotective solutions supplemented with: vitamin C (T1), vitamin E (T2), vitamin C + vitamin E (T3), cysteine (T4), taurine (T5), and taurine + cysteine (T6). The control treatment (T7) was not supplemented. Diluted semen was loaded in 0.5 mL straws, frozen in a dry-shipper, stored in a cryogenic cylinder, and then thawed in a water bath (45ºC for eight seconds). The quality of fresh and cryopreserved semen was evaluated by measuring total motility, progressive motility, curvilinear velocity (VCL), straight line velocity (VSL), average path velocity (VAP), linearity, and straightness using a computerized system of sperm analysis. Sperm membrane integrity parameters were analyzed using eosin-nigrosin staining, sperm morphology was assessed using pink bengal staining, and motility duration was measured by a digital timer. Data were analyzed using the statistical program SAS (2002) and the results were expressed as means ± standard error of the mean. The results showed that, in general, there was no significant increase in seminal quality when antioxidants were added to the cryoprotective solution. The T5 treatment promoted an increase (P < 0.05) in progressive motility when compared to T1 (6.33 ± 1.14% and 2.98 ± 0.88%, respectively). However, it did not differ significantly (P > 0.05) from the other treatments. Treatments T2 and T5 presented the highest values of VCL (34.74 ± 2.58 and 33.60 ± 1.81 μm.s-1, respectively). These were higher (P < 0.05) than T1 (26.31 ± 1.64 μm.s-1) but not different (P > 0.05) from the T7 control (30.87 ± 1.49 μm.s-1). The VSL and VAP results showed that T1 presented the lowest velocity (9.89 ± 1.75 and 15.06 ± 1.92 μm.s-1, respectively) compared to the other treatments (P < 0.05) that did not differ from each other. Combining the two vitamins (T3) or the two amino acids (T6) was not advantageous in relation to the use of only one of these antioxidants.Discussion: The present study reports, for the first time, results of the addition of antioxidants to the tambaqui seminal freezing medium. The addition of taurine and vitamin E, although not significantly different from the control treatment, resulted in a tendency to increase sperm kinetics. This effect may be due to the action of taurine as a regulator of Ca2+ transporters, which is necessary to trigger sperm activation, and to the ability of vitamin E to scavenge reactive oxygen species produced during lipid peroxidation. On the other hand, the reduced sperm quality observed when vitamin C was used may have been related to the toxicity caused by a high concentration of this vitamin. In addition, once the safe dose of antioxidants has been exceeded, the normal physiological functions of reactive oxygen species can be inhibited. Thus, it is concluded that the use of vitamin E and taurine promotes promising results of curvilinear velocity after thawing of sperm. Therefore, these treatments are recommended, as well as more tests to determine their optimal concentrations.

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.

BACKGROUND: Using sulfated polysaccharides (SP) in fish sperm freezing medium promotes cell maintenance. OBJECTIVE: To evaluate the effect of different SP concentrations, extracted from two seaweeds (Gracilaria domingensis and Ulva fasciata), as a supplement to the sperm freezing medium of Prochilodus brevis . MATERIALS AND METHODS: Five semen pools were diluted in a solution composed of 5% glucose, 10% dimethyl sulfoxide (DMSO) and different SP concentrations (0, 0.5, 1.0, 1.5, 2.0, 2.5 or 3.0 mg/mL). The samples were cryopreserved and, after 7 days, rewarmed and analyzed for morphology, plasma membrane integrity, DNA integrity, mitochondrial activity and sperm kinetics [total motility, progressive motility, curvilinear velocity (VCL), straight line velocity (VSL), average path velocity (VAP), linearity (LIN), and wobble (WOB)]. RESULTS: There was no interaction between seaweed and SP concentrations. Similar effects were observed with SP extracted from the two seaweeds, regardless of concentration. When comparing the SP concentrations, regardless of the seaweed, 1.0 mg/mL SP showed better results for VCL and VSL. For VAP and WOB, 1.0 mg/mL SP showed better results, but differed from 3.0 mg/mL. LIN followed the same pattern, but differed from SP at 2.5 and 3.0 mg/mL. For progressive motility, 1.0 mg/mL G. domingensis showed superior results compared to the control. For mitochondrial activity, G. domingensis was superior to U. fasciata, regardless of concentration. The lowest concentrations (0.5 and 1.0 mg/mL) showed the best results, regardless of the seaweed. However, the control was superior to all treatments tested. CONCLUSION: G. domingensis SP at the lowest concentrations might be a potential supplement to the P. brevis freezing medium.