The Effect of Cushioned Centrifugation, with and without Enzymatic Reduction of Viscosity, on the Motility Pattern and Kinematic Parameters of Dromedary Camel Bull Spermatozoa

In order to contribute to the development of semen processing procedures in camelids, the aims of the present study were to evaluate (i) the effect of 35% seminal plasma incubation on dromedary camel epididymal sperm motility and kinematic parameters, (ii) the effects of centrifugation, with cushion fluid and enzymatic reduction of viscosity (Papain + E64) during ejaculate processing, on the motility and kinematic parameters of dromedary camel ejaculates. The incubation with seminal plasma significantly reduced the percentage of progressively motile spermatozoa as well as the proportion of medium progressive spermatozoa whilst increasing the percentage of non-progressive spermatozoa. The centrifugation procedure improved the sperms' kinematic parameters, and the highest values were observed for samples centrifugated with cushion fluid. The samples treated with Papain + E64 showed a significant increase in both total and medium progressive spermatozoa, along with a reduction of non-progressive spermatozoa (p < 0.05). The results of this investigation show that a simple, cheap, and effective procedure, such as cushioned centrifugation, could improve the motility patterns of dromedary camel spermatozoa; in combination with enzymatic reduction of viscosity, this method leads to the best results in terms of recovery rates and sperms' kinematic parameters.

Real-time calcium measurements of live optically trapped microorganisms

A system has been developed that allows for the real-time measurement of calcium dynamics in swimming sperm. Specifically, the ratiometric dye Indo-I is used as a fluorescent indicator of intracellular calcium dynamics. The dual emissions are collected by a high-sensitivity back-illuminated CCD camera coupled to a Dual-View imaging system. From the CCD, the images are sent to a custom developed algorithm which processes the images and outputs the calcium measurements in real-time. Additionally, sperm velocity and position data are processed and outputted in real-time. The velocity and position data are obtained using a separate coupled red light (>670 nm) phase contrast imaging setup that does not optically interfere with the fluorescent imaging. Using this system the effects of optical trapping on calcium dynamics was determined. Optical trapping of sperm with a decaying focused laser power of 510 mW to 3 mW over 8 seconds causes a statistically insignificant change in calcium dynamics between in-trap and out-of-trap conditions. Progesterone, a calcium activator, was added and sperm were trapped under the 8 second power decay conditions. Progesterone treated sperm has a statistically higher average calcium level than untreated sperm, but shows no statistical difference between progesterone treated in-trap and out-of-trap conditions. Trapping at 16 seconds at 510 mW without decay, which have been shown to decrease sperm motility, shows a statistical difference between baseline pre-trap and in-trap intracellular calcium levels.