Effects Of LDL And Cholesterol Sulphate On Cryopreservation And Lipid Contents Of Goat And Sheep Spermatozoa

For the lower pregnant rate of AI with goat and sheep frozen semen than that of natural mating, the goat and sheep frozen semen were still not used commercially. One of the reasons of lower pregnant rate might be the depletion of cholesterol from goat and sheep spermatozoa during freezing leading to premature capacitation. Therefore, the paper studied on the changes of cholesterol and phospholipids of goat and sheep spermatozoa during freezing which was protected with egg yolk (EY). Then low density lipoprotein (LDL) was used to instead of egg yolk in diluents to study on the protection of spermatozoa from cholesterol depletion. Additional, Potassium cholesterol sulfate (PCS) was supplemented to LDL diluent and EY diluent to study on the ability of LDL+PCS and EY+PCS to maintain the cholesterol and phospholipids contents, motility, membrane and acrosome of spermatozoa.1. The cholesterol contents and cholesterol and phospholipids ratio of goat and sheep spermatozoa were decreased from 230.33 to175.33nmol/109 sperm and from 0.54 to 0.36 during freezing, when the egg yolk was added to the semen diluent.2. When EY was replaced with LDL in goat semen frozen diluent, LDL could maintain the cholesterol content and the ratio of cholesterol and phospholipids. LDL could also increase the motility, the rates of no-effected membrane and acrosome of frozen goat spermatozoa. So, LDL could be used to replace EY in diluent, and the suitable dosage was 9g LDL in 100ml diluent.3. When EY was replaced with LDL in sheep semen freezing diluent, LDL could maintain the cholesterol content and the ratio of cholesterol and phospholipids. LDL could also increase the motility of frozen sheep spermatozoa. Therefore, LDL could be used to replace the EY in diluent, and the suitable dosage was 9g LDL in 100 ml diluent.4. When PCS was added to the LDL diluent, PCS could increase the ratio of cholesterol and phospholipid, motility and the rate of no-effected membrane of frozen goat spermatozoa. PCS could be used as a composition in goat semen freezing diluent.5. In EY diluent, PCS could increase the ratio of cholesterol and phospholipid, motility and the rate of no-effected membrane of goat spermatozoa. So, PCS could be used as a composition in gaot semen freezing diluent and the suitable dosage of PCS was 0.10g/100ml diluent.6. In LDL diluent, PCS could increase the ratio of cholesterol and phospholipids, but did not influence the membrane and acrosom of frozen sheep spermatozoa. PCS was harmful to sheep spermatozoa during freezing.7. In EY diluent, PCS could maintain the cholesterol content and the retio of cholesterol and phospholipids of frozen sheep semen and increase the motility, the rate of no-effected membrane and acrosome. EY diluent supplemented with PCS might have batter protection to sheep spermatozosa than that of EY only in diluent during freening.