Status of Sperm Functionality Assessment in Wildlife Species: From Fish to Primates

Abstract

(1) Background: in order to propagate wildlife species (covering the whole spectrum from species suitable for aquaculture to endangered species), it is important to have a good understanding of the quality of their sperm, oocytes and embryos. While sperm quality analyses have mainly used manual assessment in the past, such manual estimations are subjective and largely unreliable. Accordingly, quantitative and cutting-edge approaches are required to assess the various aspects of sperm quality. The purpose of this investigation was to illustrate the latest technology used in quantitative evaluation of sperm quality and the required cut-off points to distinguish the differential grades of fertility potential in a wide range of vertebrate species. (2) Methods: computer-aided sperm analysis (CASA) with an emphasis on sperm motility, 3D tracking and flagellar and sperm tracking analysis (FAST), as well as quantitative assessment of sperm morphology, vitality, acrosome status, fragmentation and many other complimentary technologies. (3) Results: Assessing sperm quality revealed a great deal of species specificity. For example, in freshwater fish like trout, sperm swam in a typical tight helical pattern, but in seawater species sperm motility was more progressive. In amphibian species, sperm velocity was slow, in contrast with some bird species (e.g., ostrich). Meanwhile, in African elephant and some antelope species, fast progressive sperm was evident. In most species, there was a high percentage of morphologically normal sperm, but generally, low percentages were observed for motility, vitality and normal morphology evident in monogamous species. (4) Conclusions: Sperm quality assessment using quantitative methodologies such as CASA motility, FAST analysis, morphology and vitality, as well as more progressive methodologies, assisted in better defining sperm quality—specifically, sperm functionality of high-quality sperm. This approach will assist in the propagation of wildlife species.

Effects of Diluent pH on Enrichment and Performance of Dairy Goat X/Y Sperm

“…Researchers have also separated X and Y sperms by electrophoresis based on the differences in cell surface charge contents (Ishijima et al, 1992). Specific ligands have also been used to bind sperm-specific receptors, such as Y sperm SRY proteins (Soleymani et al, 2019), HY antigen (Yadav et al, 2017), and TLR7/8 receptor (Umehara et al, 2020). The most effective and frequently used method for sperm separation is flow cytometry sorting, which takes advantage of the different DNA contents of X and Y sperms.…”

Sperm collection and computer-assisted sperm analysis in the teleost model Japanese medaka (Oryzias latipes)

“…While an osmotic shock is typically required to activate fish sperm, it can also lead to membrane damage during the motility period, which can also impact the longevity. This effect is more critical in freshwater species (Cosson, 2010), which may explain why marine sperm are capable of longer motility duration (about 550 sec on average compared to about 150 sec for freshwater species), despite exhibiting a similar average velocity and motility as freshwater sperm (Browne et al, 2015; van der Horst et al, 2021). Motility duration longer than 30 minutes is not common, but it has been reported in several marine species (Browne et al, 2015; Cosson, 2010).…”

“…Three useful factors for assessing fish sperm quality are motility, progressivity, and longevity. Percent motility and progressive motility are common indicators of sperm quality as progressive motion is necessary for and correlates strongly with fertilization success (Kime et al, 2001; van der Horst et al, 2021). Duration of movement is also an important indicator in fish as sperm remain fully motile for less than 2 minutes in most teleost species and the trajectory of sperm is generally less linear than in mammals (Kime et al, 2001).…”

“…However, due to the important diversity in reproductive strategies between fishes, the sperm of teleost fish differs from that of mammals and from one fish species to another. Teleost fish, which primarily fertilize eggs externally by releasing gametes into water, have highly concentrated sperm that are relatively simple in structure with no acrosome, unlike mammals, which fertilize internally and therefore do not have to compensate for dilution in water, but do have to withstand more viscous fluids (van der Horst et al, 2021). Additionally, sperm from most fish move rapidly but are fully motile for less than 2 minutes after activation, although there are several exceptions (Browne et al, 2015; Kime et al, 2001).…”

Sperm morphology and testicular histology of the polyandric species Leptodactylus podicipinus (Anura: Leptodactylidae) from an urban environment

“…Sperm morphology is an important parameter in the evaluation of male fertility, and sperm morphology abnormalities are thought to be relatively uncommon in most species, with sperm assessment studies reporting high rates of normal sperm morphologies in fish, reptiles, and amphibians (Stewart et al, 2016;van der Horst, 2021).…”