Tesis doctoral sobre antioxidantes en semen

EzH3ik5WgAM6ddnLa semana pasada, el Dr. Felipe Martínez asistió como Presidente de Tribunal a la tesis doctoral de D.ª Francisca Sánchez, del grupo SaBio del IREC/UCLM. La tesis se tituló “Estrategia antioxidante para la protección espermática frente al estrés oxidativo”, y la defendió brillantemente el día 16 de abril.

Ha sido una satisfacción asistir a esta tesis, con dos de los tres trabajos presentados ya publicados en revistas de prestigio. Agradezco a los Drs. Rocío Fernández y J. Julián Garde, grandes personas y grandes investigadores, por habernos considerado para colaborar en esta tarea. Y una satisfacción compartir la mesa con los Drs. Olga García (UCLM) y Manuel Álvarez (UAB/LiU).

¡Esperemos que pronto podamos celebrarlo adecuadamente!

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Alternatives to antibiotics on artificial reproduction: New publication

We just had accepted a publication about our research on sperm selection and sperm chromatin. Dr. Morrell from SLU in Uppsala collaborates with us in this research line supported by two granted projects. In this article, “Low density Porcicoll separates spermatozoa from bacteria and retains sperm quality” (OA), we have scaled the Porcicoll SLC-based sperm selection technique to the pre-application stage. Dr. Morrell is the inventor of the colloid and one of the leading developers of SLC. She demonstrated the ability of the method for removing bacteria from ejaculates when using a low-density colloid.

We are very interested in improving the chromatin integrity of the pig sperm for industrial use, and bacterial contamination is a challenge. With this collaboration, we are enabling the use of large-volume SLC for removing bacteria from semen. Therefore, no antibiotics might be added for cooled storage. We demonstrate that after collection in conditions allowing for bacterial contamination, low-density SLC was able to remove most bacteria and keep counts low and improve sperm quality. Notably, sperm chromatin benefited by decreasing DNA fragmentation, a key event related to reduced fertility.

This research allows us to advance towards a better application of reproductive techniques while achieving H2020 objectives regarding the fight against antimicrobial resistance (AMR). Reducing antibiotic use is a positive step for the pig industry and society as a whole. Besides, we successfully carried out the experiment while processing large volumes of ejaculate, which is an incremental step towards applying these methods in the pig industry.

Below: Plots showing bacterial relationships in the sperm samples, and correlations among bacterial species and sperm quality parameters.

heatmap correl

More information:



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Convocatoria de contrato postdoctoral en nuestro grupo

Se ha abierto el plazo para solicitar una plaza de investigador postdoctoral en nuestro grupo, para dos años. 

Krawetz SA et al. 2009. Molecular aspects of male fertility. International Workshop on Molecular Andrology. EMBO Rep 10:1087-92.

Krawetz SA et al. 2009. Molecular aspects of male fertility. International Workshop on Molecular Andrology. EMBO Rep 10:1087-92.

El contrato se enmarca en un proyecto para estudiar la cromatina espermática, técnicas avanzadas enfocadas a inmunofluorescencia y citometría de flujo. No es imprescindible experiencia en esas técnicas, pero sí en biología celular y molecular en general.

La convocatoria está publicada en:


Se valorará experiencia en laboratorio, trabajo en biología del espermatozoide, capacidad para publicar, dirigir estudiantes, etc. Nuestra intención es que la persona que contratemos aproveche al máximo esos dos años para su CV: publicaciones y dirección de tesis; si hubiese posibilidad, dirección de proyectos y contratos cortos.

Las condiciones del proyecto y los detalles de los contratos están detallados en https://lnkd.in/gUWznnS


Special Issue “Molecular Determinants of Seminal Plasma on Sperm Biology and Fertility” in IJMS

ijms-logoDr. Manuel Álvarez-Rodríguez from LIU/UAB and Dr. Felipe Martínez-Pastor have co-edited a Special Issue in the IJMS on seminal plasma. We have achieved to put together 17 state-of-the-art research articles and reviews on the topic, including aspects related to human medicine, animal breeding, molecular and cellular research.

Our expectation is that this Special Issue contributes effectively to this exciting field, and that the researchers can find it useful as a valuable vault of frontier knowledge.



Manuel Álvarez-RodríguezFelipe Martínez-Pastor Seminal Plasma Induces Overexpression of Genes Associated with Embryo Development and Implantation in Day-6 Porcine Blastocysts


Low-density colloid as alternative to antibiotics and sperm chromatin improvement

How to replace antibiotics from current semen extenders? We are trying to advance in this topic with Dr. Jane Morrell from SLU and the Spanish colleagues from Topigs-Norsvin. We have just published an article in the Theriogenology journal in which we successfully test a prototype for processing large volumes of pig semen removing bacteria.

These large volumes could be processed with a low-density colloid (Porcicoll, invented by Dr. Morrell), successfully removing contaminating bacteria (skilfully tested by our colleagues of the Microbiology Group at the University of León). This system could substitute for antibiotics currently used in semen extenders.

After storing the semen doses for several days, processed samples showed lower bacterial content, higher quality and notably lower damage in the sperm genetic material. This last point is of major interest for us, as part of our current line of research on the structure of boar sperm chromatin. In subsequent studies we are studying more specifically the effect of bacterial contamination and the remediation by the colloid, and the impact on many sperm chromatin parameters.

sperm 500ml bottles

Large-volume bottles after the centrifugation in a laminar-flow hood (Cell Biology, University of León). The sperm pellet is visible. Semen medium with seminal plasma, debris and bacteria is retained on top of the colloid (barely visible).

This experiment was part of two projects (RTI2018-095183-B-I00, MCI/AEI/FEDER, EU, and LE023P20, Junta de Castilla y León/Consejería de Educación/FEDER, EU) for studying the sperm chromatin and the use of colloids for processing semen. This line of work contribute to the circular economy and the improvement of the agroalimentary sector by enhnancing the application of artificial insemination and reducing antibiotic use.

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