No abstract

No abstract

Experiments were carried out to investigate the cryoprotecting potential of dextrans (ranging from 10 to 2000 kDa) using a synthetic model system developed recently in this laboratory. Goat spermatozoa from the cauda epididymidis were extracted in a chemically defined medium (modified Ringer's solution) and assayed for motility using a phase-contrast microscope. The sperm cells were subjected to a freezing protocol in a computer-controlled biofreezer (cooling at 0.25 degrees C min(-1) to 5 degrees C; 5 degrees C min(-1) to -20 degrees C; 20 degrees C min(-1) to -100 degrees C) and plunged into liquid nitrogen. The frozen cells were thawed rapidly at 37 degrees C in a thermostatic waterbath. In the absence of dextran, all the spermatozoa lost their motility. The cryoprotecting efficacy of each dextran was found to be biphasic in nature. Initially, as the concentration of dextran was increased, the recovery of sperm motility also increased and reached an optimum value; however, with further increases in dextran concentration, the recovery of motility decreased sharply. Of all the sugar polymers tested, 10 kDa dextran showed the highest cryoprotecting efficacy, whereas the 2000 kDa sugar polymer was the least active. Dextrans of 10, 40, 73, 173, 252, 500 and 2000 kDa offered maximum cryorecovery of forward motility to the extent of approximately 23%, 21%, 19%, 18%, 16%, 15% and 8%, respectively. Optimum concentrations of these dextrans for cryoprotection of sperm motility were 8.42, 2.50, 1.09, 0.37, 0.31, 0.10 and 0.04 mmol l(-1), respectively. It thus appears that each dextran has a characteristic cryoprotection profile. The data show that the cryoprotecting efficacy and optimum cryoprotecting concentrations of dextrans are inversely related to their molecular mass. Dextran also served as a significant cryoprotectant in the presence of glycerol (0.87 mol l(-1)) and dimethyl sulphoxide (0.76 mol l(-1)), which are well known cryoprotectants; the action of the combined cryoprotectants was almost additive. The presence of glycerol or glycerol plus dimethyl sulphoxide caused a significant reduction (from 8.42 to 6.27 mmol l(-1)) in the optimum concentration of dextran. In the presence of the three cryoprotectants, recovery of sperm motility was as high as 58% (forward motility) and 60% (total motility).

Sperm forward motility is an essential parameter in mammalian fertilization. Studies from our laboratory have identified and characterized a few unique sperm motility regulatory proteins/glycoproteins from the male reproductive fluids and mammalian blood serum. The purified sperm motility-initiating protein MIP from caprine epididymal plasma as well as the forward motility-stimulating factor FMSF and motility-stimulating protein MSP from buffalo and goat serum, respectively, have high efficacy to initiate or increase motility in nonmotile or less motile sperm. "ntibody of sperm motility inhibitory factor MIF-II has the high potential to enhance sperm vertical velocity and forward motility by increasing intracellular cyclic adenosine monophosphate c"MP level. The appearance and disappearance of D-galactose-specific lectin and its receptor along the epididymis has been reported to be involved in motility regulation in spermatozoa. " novel synthetic cryopreservation method and role of lipid to protect membrane damage during cryopreservation have been demonstrated. Motility-promoting proteins may be extremely useful for improving cattle breeding and breeding of endangered species, thereby helping in enhanced production of animal products as well as in the conservation of animals. Isolated proteins and developed cryopreservation technology may also be beneficial in human infertility clinics to increase the chance of fertilization.Keywords: Spermatozoa, Epididymis, Motility regulatory proteins, Cryopreservation, Reproduction © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. . IntroductionLivestock is a very important subsector of Indian agricultural production system. The overall contribution of the livestock is almost . %. India ranks first in milk production in the world . million tons , which is mostly contributed by cattle and buffalo. The bull concentrates in itself a high economic value and thus need to be maintained on proper nutrition and management to obtain optimum performance in terms of semen production [ ]. The demand for the best males has increased considerably due to a shortage in the number of proven bulls having better semen characteristics for sustaining a successful breeding program [ ].Reproductive techniques facilitate the breeding of farm animals, which ultimately improve milk production and growth in dairy industry. "rtificial insemination "I is a first-generation reproductive biotechnology that profoundly contributed to genetic improvement, particularly in dairy cattle. Such impact would not have been possible without successfully freezing bull semen. Quality control of frozen sperm is of utmost importance for the sperm to be used in "I [ ]. Sperm cryopreservation allows prolonged preservation of semen and a wider use of a male gamete [ ]. Thi...