Association of L-arginine with heparin on the sperm capacitation improves in vitro embryo production in bovine

We aimed to evaluate the effects of L-arginine (L-arg) in the quality of in vitro heparin-induced capacitation of cryopreserved bovine spermatozoa and its effects on IVP. The experimental groups were: Control 0 hour without pre-capacitation, and groups of sperm capacitated for 30 min in the absence of COC with heparin (Control 30 min), with 1 mM L-arg and with 1 mM L-arg + heparin. The capacitation pattern was evaluated by chlortetracycline assay and the integrity of the plasma membrane (PM) and acrosome membrane (AM) by the association of Hoescht 33342 and propidium iodide. Further, we assess the sperm quality by the rate of in vitro blastocysts production. Treatment with 1 mM L-arg + heparin increased the percentage of capacitated sperm when compared to Control 0 hour and the treatment with heparin (61.1 vs. 18.2 and 47.0%, respectively, P0.05). The group capacitated with 1 mM L-arg + heparin for 30 min increased the blastocyst rate compared to Control IVF (53.7 vs. 40.8%, P<0.05). We conclude that the addition of L-arg with heparin increases the number of capacitated spermatozoa in vitro with 30 min of pre-incubation in the absence of COC not altering the integrity of plasma and acrosomal membrane. This treatment in the absence of COC was the most effective method for blastocysts production, and the method of pre-incubation could be used to assess the role of other substances in the sperm capacitation and its effect on IVP.

Association of L-arginine with heparin on the sperm capacitation improves in vitro embryo production in bovine

We aimed to evaluate the effects of L-arginine (L-arg) in the quality of in vitro heparin-induced capacitation of cryopreserved bovine spermatozoa and its effects on IVP. The experimental groups were: Control 0 hour without pre-capacitation, and groups of sperm capacitated for 30 min in the absence of COC with heparin (Control 30 min), with 1 mM L-arg and with 1 mM L-arg + heparin. The capacitation pattern was evaluated by chlortetracycline assay and the integrity of the plasma membrane (PM) and acrosome membrane (AM) by the association of Hoescht 33342 and propidium iodide. Further, we assess the sperm quality by the rate of in vitro blastocysts production. Treatment with 1 mM L-arg + heparin increased the percentage of capacitated sperm when compared to Control 0 hour and the treatment with heparin (61.1 vs. 18.2 and 47.0%, respectively, P<0.05). The addition of 1 mM L-arg to the medium has capacitated the spermatozoa (26.2 ± 3.8) but was less effective than heparin (47.0 ± 4.0) (P<0.05). There was no difference in the percentage of sperm with intact PM between treatments when compared to Control 0 hour (P>0.05). The group capacitated with 1 mM L-arg + heparin for 30 min increased the blastocyst rate compared to Control IVF (53.7 vs. 40.8%, P<0.05). We conclude that the addition of L-arg with heparin increases the number of capacitated spermatozoa in vitro with 30 min of pre-incubation in the absence of COC not altering the integrity of plasma and acrosomal membrane. This treatment in the absence of COC was the most effective method for blastocysts production, and the method of pre-incubation could be used to assess the role of other substances in the sperm capacitation and its effect on IVP.(AU)

Viabilidade econômica e de risco da produção de tomate no município de Cambuci/RJ, Brasil / Economic feasibility and risk of tomato production in the municipality of Cambuci/RJ, Brazil

A tomaticultura possui grande importância econômica e social para muitos municípios produtores e para todos os demais municípios participantes do mercado consumidor. O tomate sofre elevadas variações de preços no mercado. Tal característica expõe produtores a riscos e incertezas de preços. Nesse sentido, questiona-se o que, quanto, como, e para quem produzir? Objetivou-se analisar a viabilidade econômica da produção de tomate de mesa no município de Cambuci/RJ. Para obter os indicadores de viabilidade econômica, foram estimados o Valor Presente Líquido (VPL), a Taxa Interna de Retorno (TIR). Para determinar as incertezas do empreendimento, foi realizada a análise de sensibilidade. O risco envolvido na tomaticultura deste município foi avaliado por meio da Simulação de Monte Carlo. Os resultados mostraram indicadores econômicos satisfatórios para o período analisado. A análise de sensibilidade revelou que o preço de venda do tomate foi a variável com maior efeito sobre os resultados econômicos da atividade, seguido pelo custo da mão de obra. A simulação de Monte Carlo demonstrou que é baixa a probabilidade dos produtores de tomate obterem VPL negativo. Assim, conclui-se que o cultivo de tomate em Cambuci/RJ apresenta-se como alternativa viável para seus produtores, entretanto, variações pessimistas de preços podem inviabilizar esta atividade.(AU)

The tomato production has great economic and social importance for many municipalities producers and for all other municipalities participating in the consumer market. The tomato suffers high price changes in the market. This feature exposes producers to risks and uncertainties price. In this sense, the question is what, how, how much, and for whom to produce? This study aimed to analyze the economic feasibility of production of fresh market tomatoes in Cambuci/RJ. For the economic viability indicators were estimated Net Present Value (NPV) and Internal Rate of Return (IRR). To determine the uncertainties of the project was carried out sensitivity analysis. To assess the risk involved in tomato production this municipality Monte Carlo simulation was used. The results showed satisfactory economic indicators for the period analyzed. The sensitivity analysis showed that the selling price of tomato was the variable with the greatest effect on the results of economic activity, followed by the cost of hand labor. The Monte Carlo simulation showed that there is low probability of obtaining negative NPV for tomato growers. Thus, it was concluded that the cultivation of tomato in Cambuci/RJ presents itself as a viable alternative to producers, however, pessimistic variations in prices may derail this activity.(AU)