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

The action of substances with non-permeable cryoprotectant potential, besides glucose, has not yet been studied for the species Prochilodus brevis. The objective of this work was to evaluate the action of four non-permeable cryoprotectants on this species sperm cryopreservation. Five pools were cryopreserved in a solution of 5% glucose and 10% dimethyl sulfoxide (Me 2 SO) associated or not (control) with cryoprotectants egg yolk (5, 10 or 12%), soy lecithin (2.5, 7.5 or 10%), sucrose (5, 10 or 20%) and lactose (5, 8 or 15%). After thawing, samples were evaluated for sperm kinetics (total motility, motility duration, velocities, and wobble -WOB), morphology and membrane and DNA integrity. The treatments containing egg yolk improved significantly (P<0.05) results when compared the control for the membrane integrity parameter. When compared to other treatments, egg yolk, at any concentration, presented higher results (P<0.05) for membrane integrity, total motility, curvilinear velocity (VCL) and average path velocity (VAP) parameters. Egg yolk also showed the best results for WOB, but it did not differ from 5% and 8% lactose and 5% and 20% sucrose. Soy lecithin had the lowest percentages of morphologically normal sperm (P<0.05), while the other treatments did not differ from each other. There was no difference regarding DNA integrity data. Thus, 5% egg yolk is indicated as a non-permeable cryoprotectant for P. brevis, in association with 5% glucose and 10% Me 2 SO.

The fish species Colossoma macropomum (Curvier, 1816), also known as tambaqui, is endemic to the Amazon basin, and the Brazilian native species most commercially produced, with 102 thousand tons per year (Pedroza-Filho et al., 2020; Peixe Br., 2019), especially due to it rusticity and appreciated meat (Sousa et al., 2016;Varela-Junior et al., 2015). Moreover, C. macropomum is ecologically important, since it has been used as a bioindicator of genotoxic ultraviolet light effect (Groff, 2008). In addition, it can resist different dispersions of

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.

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.