RESUMO
Glycerol (11%; v:v) is the cryoprotectant most often used for the cryopreservation of rooster sperm. However, chicken breeds differ in the resistance of their sperm to the cryopreservation process and endangered or local breeds usually present low fertilizing ability when conventional sperm cryopreservation protocols are used. The objective of this study was to optimize the protocol for the cryopreservation of the sperm from the endangered breed "Gallina Valenciana de Chulilla". For this purpose, 10 pools of semen from 43 roosters of this breed were cryopreserved using 8%, 7%, 6%, or 4% glycerol, and the sperm quality was determined immediately after thawing and in the insemination doses. Lohmann Brown Classic laying hens (n = 40) were used for the insemination trials. The sperm quality after cryopreservation progressively decreased as the glycerol concentration was reduced (P < 0.01); samples frozen using 4% glycerol exhibited the lowest quality (38% total motile sperm and 49% live sperm), and samples frozen using 8% glycerol exhibited the highest quality (67% total motile sperm and 66% live sperm). These differences were also observed after the glycerol was removed (P < 0.01). However, the sperm fertilizing ability was similar for all the treatments (23%-30% fertilized eggs), and increased as the glycerol concentration decreased. In conclusion, semen from roosters frozen using 4% glycerol exhibited lower sperm quality but similar fertilizing ability compared with samples processed using higher glycerol concentrations. These results may provide useful information for developing cryopreservation protocols for other breeds.
Assuntos
Galinhas/genética , Galinhas/fisiologia , Criopreservação/veterinária , Glicerol/farmacologia , Preservação do Sêmen/veterinária , Espermatozoides/fisiologia , Animais , Criopreservação/métodos , Crioprotetores/química , Crioprotetores/farmacologia , Feminino , Glicerol/química , Inseminação Artificial/veterinária , Masculino , Análise do Sêmen , Preservação do Sêmen/métodos , Motilidade dos EspermatozoidesRESUMO
Se denomina metaanálisis al procedimiento estadístico que integra los resultados de estudios independientes, pero con un diseño similar. Se logra así mayor potencia estadística para detectar diferencias entre tratamientos y obtener mayor precisión en los resultados. Además de proporcionar una estimación más precisa del efecto global, en algunos casos un examen adecuado de la heterogeneidad entre los estudios individuales puede suministar información de gran relevancia clínica. En este artículo se traza un resumen de la historia, principios, métodos estadísticos y metodología del metaanálisis, así como de sus ventajas e incovenientes. El aumento actual en el número de metaanálisis que se publican en las revistas médicas y también en hipertensión refleja el creciente reconocimiento de la importancia que esta técnica tiene para mejorar el conocimiento sobre el cuidado de la salud. Y, sin embargo, los metaanálisis, incluso cuando proporcionan resultados concluyentes, reciben menos atención que los estudios que combinan, lo que hace presumir que también tienen una menor influencia en la práctica clínica. Este artículo puede ayudar a comprender la importancia y utilidad de esta técnica, que es claramente superior y más objetiva que la revisión narrativa tradicional y que, no obstante, no está libre de controversia (AU)
Assuntos
Metanálise como Assunto , Bioestatística , PesquisaRESUMO
To know the mechanisms involved in the activation of promutagenic aromatic amines mediated by plants, we used Persea americana S117 system (S117) for the activation of 2-aminofluorene (2-AF) and m-phenylenediamine (m-PDA) in Ames assays. In these assays, the effect of the diphenylene iodonium (DPI), an inhibitor of flavin-containing monooxygenases (FMOs), of the 1-aminobenzotriazole (1-ABT), an inhibitor of cytochromes P450 (cyt-P450s) and of the methimazole, a high-affinity substrate for FMOs, was studied. The efficacy of both inhibitors and of the methimazole was verified to find that they did partially inhibit the mutagenesis of both aromatic amines, activated with rat liver S9. Similarly, both inhibitors and methimazole did produce a significant decrease in 2-AF and m-PDA mutagenesis, when the activation system was S117, indicating that, similar to what occurs in mammalian systems, plant FMOs and cyt-P450s can metabolize aromatic amines to mutagenic product(s). However, the affinity of both FMOs and cyt-P450s of plant for 2-AF and m-PDA was different. Data obtained indicate that the activities of plant FMOs must be the main enzymatic system of m-PDA activation while, in 2-AF activation, plant cyt-P450s have the most relevant activities. In addition, peroxidases of the S117 system must contribute to 2-AF activation and some isoforms of FMOs and/or cyt-P450s of the S117 system, uninhibited by the inhibitors used, must be the responsible for a partial activation of m-PDA.
