| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1986: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1985: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
Little information is available about the mechanism of reduced motility and fertilizing capacity of stored and frozen-thawed poultry spermatozoa. This study was then designed to clarify the mechanism of the decrease of sperm function induced by in vitro preservation at low temperature. In this experiment, particular attention was paid to examine the occurence of lipid peroxidation of sperm membrane and permeability of plasma membrane of spermatozoa employing fresh, stored and modified spermatozoa treated with soem chemical agents which are considered to be related to the membrane function of living cells. The results obtained here are as follows:
(1) Lipid in spermatozoa is easily oxidized under aerobic conditions, but not unter unaerobic atomosphere. The lipid peroxidation of sperm was accelerated by addition of ascorbic acid which is related to the redox potential in the biological reaction.
(2) The stored spermatozoa produced more peroxidation of lipid associated with sperm membrane t
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han fresh spermatozoa. However, pH of semen samples and storage temperature (3 or 10 C) had little effect on the production of lipid peroxides in preserved spermatozoa in this study.
(3) Addition of anti-oxidants such as butylated hyroxytoluene (BHT) and acid citrate diluent (ACD) to semen lead to considerable reduction in the production of lipid peroxides in the preserved spermatozoa, suggesting the possibility of protection of membrane damages of spermatozoa by modifying semen diluents.
(4) Membrane permeability of chicken and turkey spermatozoa was altered by in vitro preservation at low temperature for a prolonged period of time (24 or 48 hrs). Uptake rates of amino acid and glucose by stored spermatozoa were considerably reduced as compared with freshly ejaculated sperm. Surprisingly enough, great difference in turkey and fowl spermatozoal membrane was observed when semen samples obtained form two birds were frozen-thawed in liquid nitrogen (-196 C). Membrane permeability of frozen-thawed rooster spermatozoa increased, whereas frozen-thawed turkey sperm showed the decreased permeability of sperm membrane. These results suggest a possible difference in membrane function between two species.
(5) Treatment of spermatozoa with membrane perturbance and modifiers resulted in big changes in membrane function, suggesting that this kind of treatment may clarify in part a possible mechanism of the functional alterations of sperm membrane in birds. Less
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