Cryopreservation of ferret (Mustela putorius furo) sperm collected by rectal massage and electroejaculation: Comparison of a decelerating and an accelerating freezing rate protocol.

The domestic ferret (Mustela putorius furo) provides a good model for developing new reproductive technologies for use with threatened related species. Such technologies could also be used in the reproductive management of this pet species. The present work reports an improved freezing protocol for ferret sperm. Semen was collected by electroejaculation plus rectal massage (in an attempt to reduce the electrical stimulation necessary) from five adult male ferrets, and then subjected to one of two freezing protocols: (a) from 5 to -35°C at 40°C/min, then from -35 to -65°C at 17°C/min, and finally from -65 to -85°C at 3°C/min-a decelerating freezing rate; and (b) from 5 to - 10°C at 5°C/min, and then from -10 to -130°C at 60°C/min-an accelerating freezing rate. After thawing, the viability and acrosomal integrity of the sperm frozen via the two-step accelerating method were better than those frozen via the three-step decelerating method (43.3 ± 3.5% and 71.2 ± 3.4% compared with 29.7 ± 3.7% and 58.8 ± 3.4% respectively; p < .05). No differences were seen between the methods with respect to sperm motility variables; most sperm (>90%) remained static with both freezing methods. In conclusion, although the method with accelerating freezing rate was associated with better post-thaw sperm viability and acrosome integrity values, neither of the two freezing methods tested provided adequate motility results after thawing. Combining rectal massage with electrical stimuli seemed to reduce the number of the latter required for successful sperm collection.

Recent advances in bird sperm morphometric analysis and its role in male gamete characterization and reproduction technologies.

Postcopulatory sexual selection through sperm competition may be an important evolutionary force affecting many reproductive traits, including sperm morphometrics. Environmental factors such as pollutants, pesticides, and climate change may affect different sperm traits, and thus reproduction, in sensitive bird species. Many sperm-handling processes used in assisted reproductive techniques may also affect the size of sperm cells. The accurately measured dimensions of sperm cell structures (especially the head) can thus be used as indicators of environmental influences, in improving our understanding of reproductive and evolutionary strategies, and for optimizing assisted reproductive techniques (e.g., sperm cryopreservation) for use with birds. Computer-assisted sperm morphometry analysis (CASA-Morph) provides an accurate and reliable method for assessing sperm morphometry, reducing the problem of subjectivity associated with human visual assessment. Computerized systems have been standardized for use with semen from different mammalian species. Avian spermatozoa, however, are filiform, limiting their analysis with such systems, which were developed to examine the approximately spherical heads of mammalian sperm cells. To help overcome this, the standardization of staining techniques to be used in computer-assessed light microscopical methods is a priority. The present review discusses these points and describes the sperm morphometric characteristics of several wild and domestic bird species.

CHARACTERIZATION OF NATURAL EJACULATES AND SPERM CRYOPRESERVATION IN A GOLDEN EAGLE (AQUILA CHRYSAETUS).

This paper describes the sperm characteristics and response to cooling and freezing of naturally ejaculated semen from a captive, adult golden eagle (Aquila chrysaetus) trained to allow sperm recovery via cooperative copulation. A basic spermiogram was prepared, and sperm motility and morphometric variables recorded using a computer-aided system. For sperm storage, the effects of a polyvinylpyrrolidone-based extender were evaluated at 5°C. The same extender was also used in freezing procedures in which glycerol (11%) and dimethylacetamide (6%) were compared as cryoprotectants. The extender preserved sperm viability over storage periods of up to 6 days. Although sperm motility and percentage live sperm values were poorer for frozen-thawed (5.8-14.6% and 44-42%, respectively) than for fresh samples (46.7 and 74.6%, respectively), no differences were seen between the effects of the two cryoprotectants. These results could be of use when attempting to store the sperm of golden eagles and other raptors.

Comparison of isoflurane and alfaxalone (Alfaxan) for the induction of anesthesia in flamingos (Phoenicopterus roseus) undergoing orthopedic surgery.

Used since the 1970s as an avian anesthetic, the neurosteroid alfaxalone has been reformulated to avoid side effects from its castor oil excipient. This case report describes the clinical use of a new alfaxalone formulation (Alfaxan) as an intravenous anesthetic induction agent in wild isoflurane-anesthetized rose flamingos (Phoenicopterus roseus). Twenty-five male and female rose flamingos underwent orthopedic surgery using isoflurane anesthesia. The animals were induced following one of two protocols: inhaled isoflurane by facemask (ISO; n = 9) or intravenous alfaxalone (2 mg/kg; ALF; n = 16). The time and quality of anesthetic induction (until first signs of muscle relaxation) and the time and quality of recovery (sternal recumbency) were recorded using a scoring system. Mild sedation was first observed at 18.4 +/- 3.8 min and 1.7 +/- 0.3 min, following isoflurane and alfaxalone administration, respectively (P < 0.001). Alfaxalone induction time was significantly shorter and induction quality was considered smoother than in the ISO group. Flamingos given alfaxalone induction required lower isoflurane concentrations for maintenance anesthesia than did flamingos induced with mask isoflurane (1.5-2 % vol vs. 4-5 % vol for ALF vs. ISO, respectively). Alfaxalone produced moderate cardiorespiratory effects not seen in the isoflurane induction group. Recovery times were similar with both protocols without significant differences in quality and length. The new alfaxalone formulation produces a safe and effective anesthetic induction in rose flamingos and has significant isoflurane-sparing effects during anesthesia.