Motility is a key factor in function of the spermatozoon and determines semen quality and fertilizing capacity. Effective motility occurs when sperm is diluted in a swimming solution, the adequacy of which is determined by factors varying according to fish species. Spermatozoon motility rate and velocity, as well as duration of the motility period, are influenced by the temperature of the water in which broodfish are held. Increase in temperature of swimming medium beyond the optimal increases cell metabolism, leading to an increase in velocity with rapid depletion of energy resources, promoting early cessation of movement. The aim of this review was to discuss current information on the influence of temperature on quantitative spermatozoon properties, which could affect sperm function. Our findings provide a greater understanding of fish sperm physiology and a biological foundation for the further development of spermatozoon motility investigations as well as reproduction technologies.

Effect of water temperature on the physiology of fish spermatozoon function: a brief review

Heat stress has an effect on motility and metabolic activity of rabbit spermatozoa

Daily exposure to summer temperatures affects the motile subpopulation structure of epididymal sperm cells but not male fertility in an in vivo rabbit model

Artificial insemination with cryopreserved semen is the most viable biotechnology for faster and increased genetic improvement in many species allowing for improved herd performance and productivity. Pakistan has 34.6 million buffalo which have major share in total milk produced in the country. Rapid increase in human population and demand for animal products motivated the researchers to increase per animal milk production using this biotechnology. In buffalo, natural breeding practice is common in the country compared to artificial insemination, low fertility rate with cryopreserved semen is main hindrance in its propagation. It is need of the hour to disseminate the knowledge of various factors and components contributing in buffalo semen cryopreservation to improve milk and fertility rate of this breed.

Cryopreservation of buffalo (Bubalus bubalis) semen-limitations and expectations

Retinol might stabilize sperm acrosomal membrane in situations of oxidative stress because of high temperatures

A total of 32 sexually mature rabbit bucks (at 6th month of age) were used in this experiment to study the effects of breed (Black Baladi -BB- vs. White New Zealand -WNZ-) and season (summer vs. winter) on libido and seminal parameters. The experimental design was completely random with four groups arranged factorially (two breeds and two seasons) with eight rabbits in each group and three months per season. The results obtained from this study indicated that, libido (14.5 vs. 21.9 sec) and physical semen characteristics represented by the volume of semen per ejaculate without gel fractions (0.70 vs. 0.49 mL), sperm-cell concentration (703 vs. 597×106/mL), total sperm output (513 vs. 293×106/ejaculate), sperm abnormalities (11.6 vs. 14.0%), acrosomal damages (8.6 vs. 11.5%), dead spermatozoa (13.9 vs. 16.0%), and advanced sperm motility (63.2 vs. 57.1%) were signifi cantly (P<0.01) better on BB rabbit bucks than on WNZ breed. In addition, these parameters proved to be signifi cantly (P<0.01) better in winter season (15.8 sec, 0.68 mL, 702×106/mL, 487×106/ejaculate, 10.7%, 8.4%, 12.7%, and 65.6%, respectively) than in summer (20.6 sec, 0.52 mL, 598×106/mL, 319×106/ejaculate, 15.0%, 11.7%, 17.3%, and 54.7%, respectively). Following the hypo-osmotic swelling test (HOST) at 75 mOsmol/L during incubation at 37oC for 20 min, the percentages of sperm motility, swollen spermatozoa, and spermatozoa with coiled tails were higher for BB bucks (16.98, 44.08, and 39.13) than for the WNZ breed (7.2, 32.3, and 26.0). This was also the case in the winter season (14.4, 42.7, and 38.5) when compared to summer (9.8, 33.7, and 26.6), respectively. We concluded that, under Egyptian conditions, both libido and semen quality in BB bucks seems to be better than those displayed by the WNZ bucks. Nevertheless, overall semen characteristics were better in winter than in the summer season.

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M.E. Emarah

Papers

Seasonal effects on semen quality in Black Baladi and White New Zealand rabbit bucks.