The effect of the breeding season, cryopreservation and physiological extender on selected sperm and semen parameters of four ferret species: implications for captive breeding in the endangered black-footed ferret

Abstract

In the present investigation, comparative baseline information on selected sperm characteristics of ejaculate spermatozoa of the domestic (Mustela putorius furo), fitch (Mustela sp.) and black-footed ferrets (Mustela nigripes) and the Siberian polecat (Mustela eversmanni) are presented. The main emphasis was to establish differences and similarities among these species in relation to semen and sperm quality during the breeding season, in cryopreservation success and in supporting sperm motility in different extenders or physiological media. The results confirm that most sperm morphology abnormalities were evident during the beginning of the breeding cycle in all four species. No significant interspecies differences were apparent in the sperm attributes examined, for all sampling months during the breeding season. Moreover, all species exhibited comparable patterns of reproductive seasonality. Cryopreservation suppressed sperm characteristics equally in all species studied. Ejaculate spermatozoa of closely related ferret species shared many similar motion characteristics using computer-aided sperm motility analysis. These results suggest that the basic sperm physiology of the ferret species under examination is very similar. Disparate to the interspecies comparisons, there were significant differences for most sperm motion parameters when spermatozoa of any of the ferrets were compared in different extenders. Assisted reproductive technologies developed for use in domestic ferret, fitch ferret or Siberian polecat may be successfully applied to captive breeding of the black-footed ferret using semen during any of the functional breeding months.

Sperm structure and motility in the eusocial naked mole-rat, Heterocephalus glaber: a case of degenerative orthogenesis in the absence of sperm competition?

“…77% (range 12-97%) in natural populations of red deer [39] and 76% (range 6-91%) in adult dogs [40]. Even the endangered black-footed ferret ( Mustela nigripes ), which is exposed to a high degree of inbreeding, had 68% normal spermatozoa in the breeding season [41]. Interestingly, in humans who typically have a low risk of sperm competition, males with more than 15% normal spermatozoa is regarded as fertile according to Strict Criteria [42] and the lower reference limit for normal forms is 4% [35].…”

The future of computer-aided sperm analysis

“…While CASA technology is widely used with excellent results in animal production laboratories and on wildlife species, 37 38 the same is not yet true for human clinical laboratories. Those who use it for this purpose have (presumably) accepted that its results are more robust than what might be obtained from inadequately trained semen analysis technicians, and/or their lower determination cost precludes the use of more accurate assessments.…”

Application of two staining methods for sperm morphometric evaluation in domestic pigs

“…Eosin-nigrosin staining is a popular method for semen evaluation in both mammals and birds ( 4 , 17 , 27 ). The method enables the analysis of sperm viability and evaluation of its morphological structure.…”