RESUMO
Veterinary drugs are potential environmental pollutants that interfere with male reproductive function. Infertility has increased, and it is known that environmental toxins contribute to declining sperm parameters. Amitraz {N,N-[(methylamino) dimeth-ylidyne] di-2,4-xylidine} (AMZ) is a formamidine pesticide widely used as an insecticide and an acaricide. The aim of this study was to evaluate the toxicity of AMZ in bovine sperm. Three experiments using frozen-thawed bovine semen incubated with AMZ for 2 h were carried out. Negative and solvent (dimethyl sulfoxide) controls were run simultaneously with treatments. In experiment 1, the AMZ concentrations used were 10, 15 and 25 µg AMZ/ml and the sperm parameters evaluated were viability, mitochondrial activity, acrosomal status, functional membrane integrity and apoptosis. In experiments 2 and 3, 25 µg AMZ/ml was used to evaluate fertilizing capacity, embryo development and blastocyst DNA damage. In experiment 1, 25 µg AMZ/ml decreased sperm viability (P = 0.01), reduced mitochondrial activity (P = 0.03) and induced apoptosis (P < 0.01). Also, 15 and 25 µg AMZ/ml affected functional membrane integrity (P < 0.01). In experiment 2, AMZ did not alter sperm-zona binding (P = 0.40) and pronucleus formation (P = 0.36). In experiment 3, 25 µg AMZ/ml decreased the rate of embryo development (P < 0.01) and increased apoptosis (P = 0.03). These results suggest that AMZ induced alterations in bovine sperm, probably affecting male fertility at concentrations that could be present in the environment.
Assuntos
Análise do Sêmen , Preservação do Sêmen , Masculino , Animais , Bovinos , Análise do Sêmen/veterinária , Sêmen , Espermatozoides , Preservação do Sêmen/veterinária , Desenvolvimento Embrionário , Criopreservação/veterináriaRESUMO
In vitro embryo production has grown in recent decades due to its great potential for cattle production. However, the quality of in vitro-produced embryos is lower compared with those produced in vivo. The postfertilization culture environment has a major influence on bovine embryo quality. We hypothesize that the inclusion of the inclusion of alpha-lipoic acid (ALA) in the in vitro culture (IVC) medium during the first 24 h would have positive effects on embryo development in vitro and cryotolerance. The aims of this study were to evaluate the antioxidant effect of ALA in IVC medium for 24 h on bovine zygotes (21 h post in vitro fertilization, IVF), day 2 cleaved embryos (46 h post-IVF), and to assess embryo quality, developmental competence, and cryotolerance after vitrification. In all experiments, IVC medium was the Control, and 2.5 µM ALA was the treatment implemented. Viability and reactive oxygen species (ROS) levels in zygotes and day 2 embryos did not differ from the Control (P > 0.05). Supplementation with ALA increased total blastocyst and hatching rates (P < 0.05). It also improved embryo quality, evidenced by the increased blastocyst total cell number and the percentage of excellent-quality embryos observed (P < 0.05). In embryos cultured with ALA and then vitrified, ALA reduced intracellular ROS levels in warmed blastocysts (P < 0.05). In conclusion, ALA supplementation to IVC medium during 24 h is a new advantage in improving embryo quality for assisted bovine reproduction.
Assuntos
Criopreservação , Ácido Tióctico , Bovinos , Animais , Criopreservação/veterinária , Ácido Tióctico/farmacologia , Espécies Reativas de Oxigênio/farmacologia , Técnicas de Cultura Embrionária/veterinária , Vitrificação , Fertilização in vitro/veterinária , Blastocisto , Desenvolvimento EmbrionárioRESUMO
The aim of this study was to evaluate the association between plasma copper (Cu) concentration and ovarian function during a fixed-time artificial insemination (FTAI) protocol and the effect of parenteral Cu administration (100 mg) at the start of such protocol (day 0) on area of preovulatory follicle (APF); area of corpus luteum (ACL), plasma estradiol (E2), and progesterone (P4) concentrations; CL blood flow (CLBF); and pregnancy rate in beef heifers and cows. In cows, plasma Cu concentration on days 0 and 7 correlated positively with APF. Copper administration increased plasma Cu concentration and decreased APF and plasma E2 concentration (day 9), without modifying ACL, plasma P4 concentration, and CLBF (day 16) in cows. Pregnancy rate was higher in Cu-supplemented cattle on day 41 after FTAI as compared with controls (58.76 and 45.28%, respectively). In conclusion, Cu administration at the beginning of the FTAI protocol increased pregnancy rate in beef heifers and cows, modifying APF and plasma E2 concentration in the latter.
Assuntos
Cobre , Sincronização do Estro , Animais , Bovinos , Cobre/farmacologia , Corpo Lúteo , Estradiol , Sincronização do Estro/métodos , Feminino , Inseminação Artificial/métodos , Inseminação Artificial/veterinária , Gravidez , Taxa de Gravidez , ProgesteronaRESUMO
Sub-optimal cattle embryo development to the blastocyst stage still is a problem when conducting in vitro production (IVP) procedures. Supplementation of in vitro maturation (IVM) medium with omega 3-polyunsaturated eicosapentaenoic acid (EPA) is an approach that might have positive effects on lipid metabolism of cattle oocytes, potentially improving subsequent embryo development. The aim of this study was to evaluate effects of EPA addition to serum-free IVM medium on pronuclear formation after in vitro fertilization, cleavage, and blastocyst rates. Effects of EPA on lipid accumulation and intracellular reactive oxygen species (ROS) generation with IVP of cattle embryos was also investigated. In all experiments, cumulus-oocyte complexes were matured in IVM medium supplemented with 0 nM, 1 nM, or 1 µM EPA for 24 h. Pronuclear formation, cleavage, and blastocyst rates were similar for embryos when there was supplementation of EPA at all concentrations to those of the control group (P > 0.05). The inclusion of 1 nM EPA in medium resulted in a greater lipid content and less intracellular ROS in day 8-embryos compared with those of the Control group (P < 0.05). There were no differences, however, when there was inclusion of 1 µM EPA compared to embryos of the Control group at the day 8 developmental stage (P > 0.05). In conclusion, supplementation with IVM medium with the 1 nM EPA concentration resulted in a lesser blastocyst lipid and intracellular ROS concentration, without modifying embryo development, therefore, EPA could be a desirable supplement to improve embryo quality in cattle.
Assuntos
Blastocisto/química , Bovinos/fisiologia , Ácido Eicosapentaenoico/farmacologia , Técnicas de Maturação in Vitro de Oócitos/veterinária , Lipídeos/química , Espécies Reativas de Oxigênio/química , Animais , Ácido Eicosapentaenoico/administração & dosagem , Técnicas de Cultura Embrionária , Desenvolvimento Embrionário , Fertilização in vitro , Metabolismo dos Lipídeos , OócitosRESUMO
Selenium (Se) is an essential trace element with important functions in animals and whose deficiency is associated with reproductive failures. The aim of this study was to investigate the effect of Se concentrations during in vitro maturation (IVM) of Bos taurus oocyte within the reference ranges for Se status in cattle. For this purpose, Aberdeen Angus cumulus-oocyte complexes (COCs) were matured in IVM medium supplemented with 0, 10, 50, and 100 ng/mL Se (control, deficient, marginal, and adequate, respectively). The results demonstrated that marginal and adequate Se concentrations added during IVM increased viability and non-apoptotic cumulus cells (CC). Moreover, the addition of Se to culture media decreased malondialdehyde level in COC with all studied concentrations and increased total glutathione content in CC and oocytes with 10 ng/mL Se. On the other hand, total antioxidant capacity of COC, nuclear maturation, and the developmental capacity of oocytes were not modified by Se supplementation. However, 10 ng/mL Se increased hatching rate. In conclusion, supplementation with 10 ng/mL Se during in vitro maturation of Bos primigenius taurus oocytes should be considered to improve embryo quality.