Effect of frame rate capture frequency on sperm kinematic parameters and subpopulation structure definition in boars, analysed with aCASA‐Mot system

Abstract

Motility is the most widely used indicator of sperm quality. Computer-Assisted Semen Analysis (CASA) allows the objective evaluation of sperm motility parameters. CASA technology is a common tool to predict semen doses in farm animal reproduction. The kinds of video cameras used until now for image acquisition have presented limited frame rates (FR), which have a negative influence on the quality of the obtained data. The aim of the present work was to define the optimal frame rate for a correct evaluation of boar sperm motility and its subpopulation structure. Eighteen ejaculates from nine mature boars of the Pietrain breed were used. Using the ISAS v1 CASA-Mot system, with a video camera working up to 200 Hz, six FRs (25, 50, 75, 100, 150 and 200 fps) were compared. ISAS D4C20 counting chambers, warmed to 37°C, were used. FR affected all the kinematic parameters, with curvilinear velocity (VCL) and BCF the most sensitive ones. All the parameters showed differences among animals. Non-linear correlation showed the asymptotic level for VCL at 212 fps, being the highest FR for all the parameters. For future studies based just on progressive motility, almost 100 fps FR for 0.5 s must be used, while when kinematics must be considered, almost 212 fps for one-second should be analysed. Three principal components were obtained (velocity, progressivity and oscillation), being similar at 50 and 200 fps. Cells were grouped in four subpopulations but with different kinematic and cellular distribution at both FRs.

Optimization of CASA-Mot Analysis of Donkey Sperm: Optimum Frame Rate and Values of Kinematic Variables for Different Counting Chamber and Fields

“…Additionally, in recent studies, while using a high-performance camera and the same study design, depending on each species that the sperm shows non-linear trajectory will need more captures to define the correct track. This explains the differences obtained in the calculation of the OFR in the bull (256 fps) [24], the boar (212 fps) [25], and the salmon (250 fps) [26].…”

The application of computer-assisted semen analysis (CASA) technology to optimise semen evaluation. A review

“…Although CASA systems have been demonstrated to possess higher accuracy than the traditional methods (Didion, 2008), errors can occur in the automatic detection of sperm trajectory and silhouette identification (Simonik et al, 2015). However, the final results of the semen samples can be influenced by several factors, such as dilution of the semen samples, time elapsed since ejaculation until examination, sample temperature, counting chamber type (Del Gallego et al, 2017), location inside the camera (Nöthling and dos Santos, 2012), number of analysed fields (Broekhuijse et al, 2011), recording frame rate (Valverde et al, 2019b), staining technique for morphological evaluation (Soler et al, 2005b;Valverde and Madrigal-Valverde, 2019) and type of CASA system (Boryshpolets et al, 2013).…”

“…As mentioned previously, few variables, such as sample concentration and dilution, frame rate (Valverde et al, 2019b), frequency of image acquisition (Acosta and Kruger, 1996), algorithm for the reconstruction of the trajectories (Morris et al, 1996), number of fields analysed and the counting chamber can affect motility results in semen evaluation even with the same CASA system (Bompart et al, 2019;Valverde and Madrigal-Valverde, 2019).…”

“…The CASA systems allow the analysis of a large number of sperm cells in a short time, thereby providing an array of quantitative data on kinematics and head sperm morphometry, thus making it possible to optimise the reliability of seminal analyses. automated semen analyses using the CASA technology, namely the type and depth of the counting chamber (Bompart et al, 2019;Valverde and Madrigal-Valverde, 2019), the dilution media, and the frame rate of image acquisition (Valverde et al, 2019b). However, this is associated with the high frame rate values that introduce significant changes in the values of few sperm kinetic parameters.…”

Sperm kinematics and morphometric subpopulations analysis with CASA systems: a review

“…All this has led to the implementation of more accurate measurements of the classical parameters by introducing metric data obtained mainly by computer assisted semen analysis (CASA) technology and the study of other specific markers of sperm function ( Barratt, Tomlinson, & Cooke, 1993;Macleod & Irvine, 1995;Fernández-Valadés et al, 2001;Álvarez-Gonçalvez, Arellano, & Pérez Carrera, 2015). Despite its advantages, CASA technology for assessing motility (CASA-Mot) could not offer its full potential since it doesn't use a system-limitation analysis (Soler, Cooper, Valverde, & Yániz, 2016;Valverde, Madrigal-Valverde, Caldeira, et al, 2019). Therefore, most laboratories using CASA-Mot systems are replacing subjective evaluations with an objective one.…”