The spermatozoa of the dasyurid marsupial, Sminthopsis crassicaudata, are highly susceptible to cold shock

2010 ◽  
Vol 22 (3) ◽  
pp. 580 ◽  
Author(s):  
N. A. Czarny ◽  
J. C. Rodger

Since the late 1970s research has suggested that marsupial spermatozoa did not suffer cold shock. We have re-examined cold shock to investigate problems with freezing of spermatozoa from a dasyurid marsupial, the fat-tailed dunnart (Sminthopsis crassicaudata). Epididymal spermatozoa were rapidly cooled to 0.5°C in a pre-cooled tube held in an iced-water slurry. Upon re-warming all spermatozoa were immotile and the addition of 10% or 20% egg yolk to the sperm medium had no beneficial effect. Spermatozoa that were rapidly cooled to 4°C maintained only 2% motility when re-warmed but the addition of at least 10% egg yolk was beneficial and upon re-warming greater than 65% of the initial motility was maintained. In order to achieve motile spermatozoa at 0°C, controlled-rate cooling at 0.5°C min–1 was examined. In the absence of egg yolk there was a significant decline in the percentage of motile spermatozoa below 4°C. However, the inclusion of at least 10% egg yolk resulted in no loss of motility in spermatozoa cooled to 0°C. This is the first experimental study indicating that spermatozoa from a marsupial are highly susceptible to cold shock and that the impact of rapid chilling can be mitigated by the addition of 10% egg yolk. The ability to successfully cool the spermatozoa of S. crassicaudata to 0°C may have an important role in future studies examining dasyurid sperm cryopreservation.

2009 ◽  
Vol 21 (9) ◽  
pp. 61
Author(s):  
N. A. Czarny ◽  
J. C. Rodger

Carnivorous marsupials are native Australian predators including the highly threatened northern quoll (Dasyurus hallucatus) and Tasmanian devil (Sarcophilus harrisii). These species are currently actively managed in captive populations but assisted reproductive techniques such as gamete banking may also contribute to their conservation. Previous studies on a model dasyurid, the fat tailed dunnart (Sminthopsis crassicaudata), have found that spermatozoa do not survive freezing and thawing using a variety of freezing protocols and cryoprotectants. We have re-examined cold shock to investigate problems with sperm cryopreservation in S. crassicaudata. Epididymal spermatozoa were rapidly cooled to 0.5ºC in a pre-cooled tube held in an iced water slurry and upon re-warming the spermatozoa were non-motile (n=6). The addition of up to 20% egg yolk, which is considered protective to the spermatozoa of cold shock sensitive eutherians, did not improve the outcome (n=6). Similarly when S. crassicaudata spermatozoa were rapidly cooled to 4ºC, just 2% remained motile upon re-warming (n=10). However when spermatozoa were combined with at least 10% egg yolk and rapidly cooled to 4ºC only small reductions in motility were observed upon rewarming (n≥8). In order to achieve motile spermatozoa at 0ºC, controlled rate cooling at 0.5ºC/minute was examined. In the absence of egg yolk there was a decline in the percentage of motile spermatozoa below 4ºC (n=6). However if spermatozoa were combined with at least 10% egg yolk there was no significant loss of motility at temperatures as low as 0ºC (n=6). This study has revealed that at least one species of marsupial is highly susceptible to cold shock. These paradigm shifting findings give direction to future experiments aiming to develop a robust technique for sperm preservation in endangered dasyurids.


1996 ◽  
Vol 8 (4) ◽  
pp. 673 ◽  
Author(s):  
DA Taggart ◽  
CM Leigh ◽  
VR Steele ◽  
WG Breed ◽  
PD Temple-Smith ◽  
...  

The effects of long-term cooling and freezing on sperm motility are described for six marsupial species: the fat-tailed dunnart, koala, brushtail possum, long-footed potoroo, northern brown bandicoot and ring-tailed possum. The effects of up to eight days of cooling at 4 degrees C on the motility of dunnart spermatozoa and the effect of cryopreservation on spermatozoa of the other species were determined. The cryoprotectant used was a Tris-citrate-fructose-egg yolk-glycerol diluent. The percentage and rating of sperm motility, and sperm structure, as determined by light microscopy, were investigated. Sperm motility in the fat-tailed dunnart was retained for up to six days when cooled to 4 degrees C, suggesting that sperm from this species have some degree of tolerance to cold shock. After this time, however, the percentage of motile spermatozoa and their motility rating declined. In all species except the fat-tailed dunnart, reinitiation of motility following cryopreservation occurred across a range of glycerol concentrations (4-17%). Cryoprotectant containing 6% and/or 8% glycerol resulted in little change of motility rating or of the percentage of live sperm after thawing, although there was some decline in the percentage of motile sperm. The unusual structural and motility characteristics of dunnart spermatozoa may account for the lack of success of sperm cryopreservation in this species.


2020 ◽  
Vol 92 (3) ◽  
pp. 30901
Author(s):  
Suvanjan Bhattacharyya ◽  
Debraj Sarkar ◽  
Ulavathi Shettar Mahabaleshwar ◽  
Manoj K. Soni ◽  
M. Mohanraj

The current study experimentally investigates the heat transfer augmentation on the novel axial corrugated heat exchanger tube in which the spring tape is introduced. Air (Pr = 0.707) is used as a working fluid. In order to augment the thermohydraulic performance, a corrugated tube with inserts is offered. The experimental study is further extended by varying the important parameters like spring ratio (y = 1.5, 2.0, 2.5) and Reynolds number (Re = 10 000–52 000). The angular pitch between the two neighboring corrugations and the angle of the corrugation is kept constant through the experiments at β = 1200 and α = 600 respectively, while two different corrugations heights (h) are analyzed. While increasing the corrugation height and decreasing the spring ratio, the impact of the swirling effect improves the thermal performance of the system. The maximum thermal performance is obtained when the corrugation height is h = 0.2 and spring ratio y = 1.5. Eventually, correlations for predicting friction factor (f) and Nusselt number (Nu) are developed.


2019 ◽  
Vol 15 (02) ◽  
pp. 26-29
Author(s):  
Amarjeet Amarjeet ◽  
C T Khasatiya ◽  
L Chaudhary

The present investigation was carried out to study the refrigeration preservation of the cauda epididymal retrieved spermatozoa of buck in Tris egg yolk citrate (TEYC) dilutor containing pomegranate juice as antioxidant additive. The retrieved cauda epididymal spermatozoa extended in TEYC dilutor were studied in five groups by adding different concentration of pomegranate juice as additive (0% as control T1 group and 5%, 10%, 15% and 20% as treatment T2, T3, T4 and T5 groups, respectively) and storing at refrigerated temperature up to 48 hr. The results showed that the control extender had the least dead, abnormal and HOS non-reacted sperm percent among all treatments tested and that with increasing the pomegranate juice concentration in dilutor, the percentage of the dead, abnormal and HOST non-reacted spermatozoa increased significantly. The same trend was observed at all 12 hourly storage intervals indicating its detrimental effect on epididymal sperms of bucks at refrigeration temperature. The dead, abnormal, and HOST non-reacted sperm were significantly and positively interrelated with each other (r = 0.53-0.83). It was concluded that the inclusion of pomegranate juice in TEYC dilutor did not show any beneficial/antioxidant effect on epididymal sperms of buck in fresh or refrigerated semen and in fact all the levels of pomegranate juice (5% to 20%) were detrimental to cauda epididymal spermatozoa of a buck.


2019 ◽  
Vol 15 (01) ◽  
pp. 71-74
Author(s):  
L M Chaudhary ◽  
C T Khasatiya ◽  
Amarjeet Amarjeet ◽  
A B Yede

The study was carried out on the preservation of epididymal spermatozoa of buck at refrigerated temperature without and with tomato juice as a supplement in Tris egg yolk citrate extender. The eight pairs of testicles including epididymis (total 16) from slaughtered bucks were collected within 2–4 hours of their slaughter. Sperms collected from cauda epididymis were preserved at refrigerated temperature up to 48 hours in tris egg yolk citrate extender at 300 million sperm/mL with different concentration of tomato juice (0%, 4%, 6%, 8%, and 10%) and the physical characteristics of spermatozoa were assessed to know the effect of tomato juice (Tj). The mean dead, abnormal and HOST non-reacted spermatozoa increased significantly (p less than0.05) at every 12-hour intervals of preservation in the dilutor without and with different concentration of tomato juice. Tomato juice exerted an adverse effect on physical characteristics of sperm during refrigeration preservation. All the three sperm traits studied however revealed significant (p less thaN 0.01) positive interrelationships with correlations of 0.31 to 0.72.


2020 ◽  
Author(s):  
V. L. Kocharin ◽  
A. A. Yatskikh ◽  
D. S. Prishchepova ◽  
A. V. Panina ◽  
Yu. G. Yermolaev ◽  
...  

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