Nathalie Ommundsen Pessoa

Out-of-season sperm cryopreserved in different media of the Amazonian freshwater fish pirapitinga (Piaractus brachypomus)

The pirapitinga (Piaractus brachypomus) is a freshwater fish that inhabits the Amazon and Orinoco River basins. The use of cryopreserved sperm has been considered to facilitate procedures during the artificial reproduction. The aim of the present study was to develop a freezing protocol for pirapitinga sperm collected outside the spawning season. Sperm samples were diluted in four freezing media prepared by a combination of two extenders (glucose and BTS-Beltsville Thawing Solution) and two cryoprotectant agents (DMSO and methylglycol) loaded into 0.5-mL straws, frozen in a nitrogen-vapor shipping dewar (dry-shipper) and stored in liquid nitrogen at -196 degrees C. Post-thaw sperm motility was evaluated both subjectively using a light microscope and by a computer-assisted sperm analyzer (CASA). Curvilinear, average path and straight-line velocities were also determined. There were no differences (P>0.05) in post-thaw sperm motility between evaluations performed subjectively and using the CASA. Sperm samples cryopreserved in glucose-methylglycol yielded the greatest post-thaw sperm motility (81%) and fastest sperm velocities when compared to the samples frozen in the other three media (P<0.05). Out-of-season sperm cryopreserved in glucose and methylglycol under the conditions described above is of high quality and can therefore be used to facilitate artificial reproduction procedures, as only females will need handling for hormonal induction and gamete collection during the spawning season. Although the CASA system provides precise data on sperm motility, the subjective evaluation is practical and can be conducted by well-trained personnel at commercial fish farms as an acceptable evaluation of sperm quality.

Cooling of pirapitinga ( Piaractus brachypomus ) embryos stored at −10ºC

Cryopreservation has not been used successfully to preserve fish embryos, although chilling techniques have been used with good results. The aim of this study was to chill Piaractus brachypomus embryos at - 10°C for various storage times. Embryos at the following ontogenetic stages were used: blastoderm - 1.2 hours post-fertilization (hpf); epiboly - 5 hpf; blastopore closure - 8 hpf; and appearance of the optic vesicle - 13 hpf. One hundred embryos were selected from each ontogenetic stage and chilled at - 10°C for 6 or 10 h. The results were analysed using analysis of variance (ANOVA) and Tukeys test at a 5% significance level. A significantly greater number of completely developed live larvae were observed following embryonic treatment with a cryoprotectant solution that contained 17.5% sucrose and 10% methanol. There was no survival for embryos cooled at - 10°C in initial developmental stages (1, 2 and 5 h hpf). Furthermore, higher survival rates were observed when embryos were treated at more advanced developmental stages (8 and 13 hpf). Therefore, P. brachypomus embryos at the blastopore-closure (8 hpf) or appearance-of-optic-vesicle (13 hpf) stages should be used for embryo chilling protocols and chilling should be performed using a 17.5% sucrose with a 10% methanol solution at - 10°C for up to 6 h. The best results were obtained with 13-hpf and 8-hpf embryos and cooling at 6 h of storage.

Crotalus durissus venom: biological effects and relevant applications. A Review

Snakes have an important biological role in the ecological chain, as well as in scientific researches performed with the venoms produced by them, since the enzyme-protein fractions these substances possess have been studied as pharmacological tools for the discovery of new therapies. Snakes of the genus Crotalus have gained significant relevance in the scientific field, since the venom produced by these reptiles has been the target of researchers in a few decades, due to the composition and the effects that these substances can produce. In Brazil, a single species represents the genus, which is Crotalus durissus. This review demonstrates that even with the advancement in scientific research on the composition, role and application of the venom produced by the subspecies of Crotalus durissus snake, it is necessary to further study their fractions and their action potential, which also demonstrates the how rich are these active components in different fields of biomedicine.

Feline hypertrophic cardiomyopathy relevant aspects

Hypertrophic cardiomyopathy is a clinically heterogeneous disorder characterized by mild to severe thickening of left ventricular chamber associated with diastolic dysfunction. The main clinical signs are typically respiratory abnormalities secondary to pulmonary edema and/or pleural effusion; mild to severe acute heart failure; and paraparesis/paraplegia caused by arterial thromboembolism. The diagnosis should be based on a positive family history and the causes that cause secondary hypertrophy should be discarded. Echocardiography is currently the gold standard for the diagnosis of this pathology. It is the most common heart disease in adult cats; therefore, it is necessary knowledge of the condition in order to perform an effective clinical management, improving prognosis and quality of life of the animal.