摘要
Objective:To investigate the effects of non-permeable cryoprotectant,cholesterol-loaded cyclodextrin,when added at different concentrations into cooled and frozen-thawed semen extended with Tris-citrate-fructose egg yolk glycerol and lecithin-based extenders.Methods:A total of 40 ejaculates from four buffalo bulls were collected using artificial vagina.Ejaculates were extended with one of Tris-citrate-fructose egg yolk glycerol and lecithin-based extenders which contained different concentrations[0(control),0.75,1.50,2.25 and 3.00 mg/mL]of cholesterol-loaded cyclodextrin.The extended semen samples were cooled to 5曟and then frozen slowly to-196曟in 0.25 mL ministraws before being stored in liquid nitrogen pending its evaluation.Sperm motility,live sperm,normal sperm morphology,sperm membrane integrity and acrosome morphology were measured.Results:Supplementation of cholesterol-loaded cyclodextrin improved progressive motility,viability,morphology and acrosome as well as plasma membrane integrities at 1.50-2.25 mg/mL depending upon types of used extenders and stages of pre-and post-freezing process(P<0.01).The best concentration was 1.50 mg/mL at pre-freeze stage and 2.25 mg/mL at post-freezing.However,greater concentration(3.00 mg/mL)of cholesterol-loaded cyclodextrin had a detrimental effect compared to the control group with the two evaluated extenders(P<0.01).Conclusions:Cholesterol-loaded cyclodextrin supplementation at 1.50-2.25 mg/mL concentration could improve pre-frozen and post-thawed buffalo sperm quality.The most suitable concentration is 1.50 mg/mL at pre-freeze stage and 2.25 mg/mL at post-freezing.
