Weaknesses in reports of “fertility” for horses and other species

Amann, R. P.

doi:10.1016/j.theriogenology.2004.04.010

Cited by 60 publications

(31 citation statements)

References 16 publications

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“…The relationships shown here could be of biological significance because of the correlation between the different ROS variables and their relationship with fertility. However, the numbers of mares inseminated per stallion were small and these results should be confirmed on a larger set of stallions and mares as inferences from fertility trials cannot be made reliably on small samples (Amann, 2005). Interestingly, the foaling rates were mostly better than average for cooled semen, being 70% to 91% in the present study compared with 65.2% reported by Rota et al (2004).…”

Section: Discussioncontrasting

confidence: 63%

Naturally and stimulated levels of reactive oxygen species in cooled stallion semen destined for artificial insemination

Johannisson

Lundgren

Humblot

et al. 2014

Animal

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The decrease in foaling rates after artificial insemination with cooled semen warrants the search for new predictors of fertility. The objectives were to investigate levels of naturally occurring reactive oxygen species (ROS) in cooled, stored stallion semen doses for artificial insemination (AI), and their relationship with parameters of semen quality and with pregnancy rate. Semen was collected from warmblood stallions (n = 15) and used to prepare commercial semen doses for AI. Sperm quality was evaluated after cooled transport to the laboratory overnight. The results were correlated with observed foaling and pregnancy rates. Hydroethidine and dichlorodihydrofluorescein diacetate were used as indicators for the ROS superoxide and hydrogen pero xide, respectively. Sperm morphology, motility, plasma membrane integrity and chromatin integrity were also evaluated. These variables were correlated with each other and with pregnancy rates. We found a high inter-individual variation in the ROS levels between stallions. The proportion of live, hydrogen peroxide-negative spermatozoa was correlated with progressive motility, whereas live hydrogen peroxide-negative spermatozoa and chromatin damage were negatively correlated, indicating that low levels of hydrogen peroxide were correlated with good chromatin integrity. The percentage of dead hydrogen peroxide-positive sperm was negatively related to the foaling rate. The negative relationships were stronger when combining results from both assays for ROS. These results for stored semen samples indicate that high individual variation exists for superoxide and hydrogen peroxide measurements, and that ROS status can influence sperm quality. Thus, ROS may be some of the factors influencing fertility. Moreover, combinations of ROS variables improved the correlation with fertility, indicating the usefulness of including these variables in a future model for prediction of the fertility of a semen sample.

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Section: Discussioncontrasting

confidence: 63%

Naturally and stimulated levels of reactive oxygen species in cooled stallion semen destined for artificial insemination

Johannisson

Lundgren

Humblot

et al. 2014

Animal

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“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14] Most of these reviews and the literature cited therein consistently concur to a basic fact; routine spermiogram evaluations are suitable to identify clear-cut cases of infertility and, sometimes, to provide cues for potential subfertility, but are not able to prognose levels of fertility of the semen (or the male) in question. 7,13,15,16 The reason is quite obvious: such assessments simply evaluate basic variables of sperm appearance and viability, but cannot disclose subjacent structural details, biochemical and metabolic details, or the capacity of spermatozoa to interact with the environment, in terms of membrane reactivity, unless a battery of tests is used. Neither can they measure whether the genomic message spermatozoa deliver to the gamete counterpart during fertilization is intact enough to warrant the development of the early embryo.…”

Section: Introductionmentioning

confidence: 99%

Flow cytometry for the assessment of animal sperm integrity and functionality: state of the art

Hossain¹,

Johannisson²,

Wallgren³

et al. 2011

Asian J Androl

139

120

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Flow cytometry is now a recognized methodology within animal spermatology, and has moved from being a research tool to become routine in the assessment of animal semen destined to breeding. The availability of 'bench-top' flow cytometers and of newer and versatile markers for cell structure and function had allowed the instrumentation to measure more sperm parameters, from viability to reactiveness when exposed to exogenous stimuli, and to increase our capabilities to sort spermatozoa for potential fertilizing capacity, or chromosomal sex. The present review summarizes the state of the art regarding flow cytometry applied to animal andrology, albeit keeping an open comparative intent. It critically evaluates the present and future capabilities of flow cytometry for the diagnostics of potential fertility and for the development of current reproductive technologies such as sperm freezing, sperm selection and sperm sorting. The flow cytometry methods will probably further revolutionize our understanding of the sperm physiology and their functionality, and will undoubtedly extend its application in isolating many uncharacterized features of spermatozoa. However, continuous follow-up of the methods is a necessity owing to technical developments and the complexity of mapping spermatozoa.

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“…sperm doses from a normal stallion, processed and stored under optimal conditions, used for AI in normal mares by experienced personnel. A large sample size is needed to compensate for extraneous variables [20]. Such a fertility trial requires considerable time and resources and is beyond the scope of the present review.…”

Section: Advantages Of Slc For Preparing Stallion Sperm Doses For Aimentioning

confidence: 99%

Biomimetics in Action: Practical Applications of Single Layer Centrifugation for equine breeding

Jm¹

2011

J Veterinar Sci Technolo

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Single Layer Centrifugation (SLC) of spermatozoa through a species-specific colloid has been shown to be effective in selecting the best spermatozoa from stallion semen. The method is easier to use and less time-consuming than density gradient centrifugation (DGC), and has been scaled-up to allow whole ejaculates to be processed in a practical manner. The major applications for SLC-sperm selection are as follows: to improve sperm quality in artificial insemination (AI) doses, particularly for "problem" stallions; to increase the "shelf-life" of normal sperm samples, either by processing the fresh semen before preparing AI doses, or by processing the stored semen dose to extract the best spermatozoa; to circumvent the problem of spermatozoa that do not tolerate cooling to 4-6°C; to improve cryosurvival by removing dead and dying spermatozoa prior to cryopreservation, or selecting the live spermatozoa post-thawing; to select morphologically normal spermatozoa with intact chromatin from sub-fertile stallion semen for ICSI, thus increasing the number of blastocysts; to remove pathogens (viruses, bacteria); to accelerate the process of flow cytometric sex selection by removing the dead and dying sperm before passage through the laser beam; to conserve rare breeds. These applications are discussed and practical examples provided.

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Weaknesses in reports of “fertility” for horses and other species

Cited by 60 publications

References 16 publications

Naturally and stimulated levels of reactive oxygen species in cooled stallion semen destined for artificial insemination

Naturally and stimulated levels of reactive oxygen species in cooled stallion semen destined for artificial insemination

Flow cytometry for the assessment of animal sperm integrity and functionality: state of the art

Biomimetics in Action: Practical Applications of Single Layer Centrifugation for equine breeding

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