Functional integrity of sex-sorted, frozen-thawed boar sperm and its potential for artificial insemination.
Despite being developed in its present form 20 years ago, sex-sorting of mammalian sperm is still a work in progress. While relatively successful in cattle and sheep, the unique challenges of incorporating sex-sorted sperm into pig production have not yet been overcome. Generally speaking, boar sperm survive freeze-thawing less well and are required in larger numbers for insemination, while in vitro embryo production of pig embryos is less successful compared to other domestic species [Niemann H, Rath D. Progress in reproductive biotechnology in swine. Theriogenology 2001;56:1291-1304]. Due to the large number of sperm required for artificial insemination in pigs, a technique of storing sperm after sorting must be developed while adequate numbers of sperm are allocated into X- or Y-chromosome-bearing enriched pools. Cryopreservation is perhaps the ideal method of storage between sorting and insemination, as it allows unlimited time to build up a sperm bank, whereas liquid-storage requires the use of sperm within days of sorting. The limited number of studies investigating the survivability of sex-sorted, frozen-thawed boar sperm have produced promising in vitro results but poor in vivo outcomes. Before fertility can be improved, the causes of any damage to sperm function during the sex-sorting and freeze-thawing procedures must be more fully understood. Once defined, the source of damage may be minimised and this would lead to increased success rates after in vivo application of sex-sorted, frozen-thawed boar sperm.
Bathgate
R
R
Centre for Advanced Technologies in Animal Genetics and Reproduction, The University of Sydney, NSW 2006, Australia. roslynb@vetsci.usyd.edu.au
D000818:Animals; D002498:Centrifugation; D015925:Cryopreservation / Q000662:veterinary*; D003470:Culture Media; D005260:Female; D005298:Fertility; D007315:Insemination, Artificial / Q000379:methods*; D008297:Male; D011247:Pregnancy; D012743:Sex Preselection / Q000662:veterinary*; D013094:Spermatozoa / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D013552:Swine / Q000502:physiology*; D014466:Ultraviolet Rays
D003470:Culture Media