D.J. Denniston

THE EFFECT OF LIPOSOMES COMPOSED OF PHOSPHATIDYLSERINE AND CHOLESTEROL ON FERTILITY RATES USING FROZEN THAWED EQUINE SPERMATOZOA

Summary The objective of this study was to determine if the addition of liposomes composed of phosphatidylserine (PS) and cholesterol (CH) to equine sperm would improve pregnancy rates after sperm were cryopreserved. Ejaculates from four stallions, collected every other day during May and June were split, treated with PSCH liposomes or HBS (Hepes Buffered Saline) and cryopreserved. Fifty-two mares were bred over eighty estrous cycles with the frozen-thawed semen. The one cycle pregnancy rates of the mares inseminated with semen treated with liposomes (45%) were similar to mares inseminated with control semen (48%; p>0.05). Thus, at least at the levels used, PSCH liposomes added to equine sperm did not improve pregnancy rates of mares inseminated with cryopreserved semen.