The finding is partly based on observation and partly on the product of mathematical modelling. The model has looked at the collective behavior of sperm and it could lead to a new technique for selecting the best semen for artificial insemination in livestock.
The new technique comes from researchers at Imperial College in London and it has stemmed from attempts to improve the success rates with artificial insemination. Here the findings suggest that the most active semen, meaning strongly swimming sperm, relate to the most fertile males.
The difficulty is with defining active semen and what this means in turns of the speed that sperm moves at and the directions sperm takes. In the past this has been a somewhat subjective measure, judged by scientists peering down at semen samples underneath a microscope. This is based on something called the mass motility (MM) scale.
The new technique looks at sperm movement in a more sophisticated way, assessing the speed of rotating semen. This is based on an assessment of various physical measures. To achieve this, the research group discovered that when semen is confined to a ring of plastic on the microscope slide, then at a given certain sperm concentration the collective sperm begins to start to collectively rotate in one direction. However, when the concentration is low this unified movement is not observed and the sperm move in random directions. With random direction the chance of sperm making contact with an egg are far lower.
Trials, led by Professor Pierre Degond, from the Department of Mathematics at Imperial, have been undertaken using ram’s semen together with computer imaging. The results are more sophisticated than with current manual counting measures.
The key question is whether what has been observed with rams is similar with people and whether this can offer new clues about fertility.
The unusual research has been published in the Journal of the Royal Society Interface. The research paper is titled “Symmetry-breaking phase transitions in highly concentrated semen.”
