Validation of the iSperm for assessing rhinoceros Sperm

Abstract

This study's objective was to determine the feasibility of using a portable computer-assisted sperm analyzer to standardize the evaluation of rhinoceros sperm motility and concentration. Assessments were performed opportunistically as part of other ongoing studies and included both fresh and cryopreserved samples from black (Diceros bicornis; n = 3), white (Ceratotherium simum; n = 7), and greater one-horned (Rhinoceros unicornis; n = 5) rhinoceroses. Accuracy of the iSperm Rhino 5 software in identifying sperm cells was evaluated through manual scoring of sperm tracks (n = 48 videos from 12 samples). The number of sperm identified by the observer and the software were significantly correlated (Pearson r = 0.9908, P < 0.0001). Moreover, the bias between the observer to iSperm values was small (Bland-Altman test; mean ratio = 0.97 observer/iSperm). A strong correlation (Pearson r = 0.9847, P < 0.0001) between hemocytometer counting and the iSperm for sperm concentration (n = 50) was also observed with a bias of just 1.03 (mean ratio hemocytometer to iSperm). Reliability analysis was performed by comparing ten consecutive evaluations on four different samples using intraclass correlation coefficients (ICC). In this study, the reliability (aka repeatability) of measuring the concentration or total motility via iSperm was deemed excellent (ICC > 0.96). Results of this work demonstrate that the iSperm offers a reliable and semi-automated alternative to manual evaluations for assessing sperm concentrations and motility in the rhinoceros. The ability to determine wildlife sperm concentrations rapidly and motility objectively while working under field conditions would be a great asset to conservation biologists in both zoological institutions and wildlife reserves.