Dear Friend, '

Happy to see you here again plan for a met up whenever your here in INDIA.

And coming to your question, According to my experience I have not noticed any significant difference in cryosurvival index of sperm cells. Some studies have shown that TYB along with glycerol will give better results when compared to TYB or Glycerol alone.

Regards,

Sanketh Dhumal S

Glycerol with TYB is an accepted cryopreservative for sperm from many species; glycerol supplemented medium is also accepted, in particular for species or circumstances where additional animal source biologicals are not wanted in the medium. Egg yolk from a few avian species has been tested, but chicken egg yolk is the most common source material, dating back to work with bovine sperm. The LDL fraction of the egg yolk has some beneficial properties, generalizing, including protection of sperm membranes during cooling and freezing, and the LDL's can also bind other semen proteins to further protect sperm cell membranes. On the whole, there are a number of publications, particularly in humans, where the two basic solutions are comparable. In my own experiences, I prefer egg yolk extenders and cryopreservation media, where in-house comparisons have trended towards better cryo-survival post-thaw with egg yolk base media. Other LDL sources may be useful, for example soy lecithin has been used as a non-animal LDL source for livestock media, and a few human sperm trials have shown that it can be used to replace egg yolk.

For freezing sperm, egg yolk based medias have previously been found to be superior to non-egg yolk media (Paras et al., 2008, Hammadeh et al., 2001, Duru et al., 2001). Why egg yolk confers such improvements is unknown, though several plausible explanations have been suggested (Holt, 2000). Egg yolk has been found to be cryoprotective on its own (Sherman, 1990) and both phospholipid and protein isolated from the low-density lipoprotein fraction of egg yolk are active constituents (Watson, 1981).

If you’re talking about a commercial freeze media. It probably also has detergents, antioxidants, antibiotics, buffers, etc. So there are a lot of these other factors to consider. On a population basis media with egg yolk will be better overall. For any individual alone, you would expect an individual response, i.e. some people will have a better response to one of the media types and vice versa.

Duru, N. K., Morshedi, M. S., Schuffner, A. & Oehninger, S. (2001). Journal of Andrology 22, 646-651.

Hammadeh, M. E., Georg, T., Rosenbaum, P. & Schmidt, W. (2001). Andrologia 33, 331-336.

Holt, W. V. (2000). Animal Reproduction Science 62, 3-22.

Paras, L., Freisinger, J., Esterbauer, B., Schmeller, N., Szlauer, R. & Jungwirth, A. (2008). Andrologia 40, 18-22.

Sherman, J. (1990). CRC Handbook of the Laboratory Diagnosis and Treatment of Infertility. , edited by B. A. Keel, Webster, B.W., pp. 229-259. Boca Raton: CRC Press.

Watson, P. (1981). Journal of reproduction and fertility 62, 483-492.

depending on semen specy . For poultry , fish ,equine , donkey won't be suitable

then the final % of Gly is important (varies from 4 to 7 %)

I would rather prefer to use for :bovine ,sheep, goat, canine an extender with liposome. it gaves you the flexibility to freeze on the following day of the semen collection .

Glycerol is relatively safer and very effective than other cryoprotectants in cryopreserving sperm from bovine and human. Its usual concentration for human sperm is 7 % . Many semen extenders / buffer media have been used to dissolve glycerol to get final glycerol conc of 7 %. In my experience TYBG provides the best survival. Not only sperm survival but the forward progressive motility is higher. Proteins and lipids from egg yolk protects sperm membrane better than other supplements. However, the egg yolk has to be tested thoroughly and free from pathogens so that the recipients are safe.

It is well known that egg yolk or soy lecithin or lecithin protect sperm from cold shock and glycerol or DMSO or propylene glycol from the cryo injuries. Egg yolk is better than others but being a biological material there is always chances of contamination and day to day variability in the quality of yolk which may affect the quality of preserved semen. Glycerol 5 to 7 % depending on the species is better. So the media or extender should contain both egg yolk and glycerol in optimum concentration for protecting sperm from cold shock (during the process of cooling from ambient temperature to 5°C) and from cryo injuries (during the process of freezing from 5°C to - 196°C)

Thank you Davendra

Dear Hemraz: To what Davendra Kumar and Guy Delhomme tells you very well, I would ask you in which animal species do you plan to work using egg yolk or soya lecithin and glycerol or DMSO or propylene glycol? Because it is a very important fact, especially in the use of egg yolk or soya lecithin.

i have used inra96 with 5% glycerol -no egg yolk- In horses and it worked very well. I guess the phosphocaseinate in the extender confered cryoprotection comparable to egg yolk?