Abstract: 【Objective】 The purpose of this experiment was to explore the effects of adding heat shock protein A8 (HSPA8) before freezing and adding different concentrations of seminal plasma (SP) after thawing on frozen-thawed boar sperm.【Method】 The semen of Landrace boars was collected by hand holding method, 0.5 μg/mL HSPA8 was added to the boar semen cryopreserved agent for French straws, and then stored in liquid nitrogen for 3 weeks before thawing.After thawing, different concentrations of seminal plasma (0, 10%, 30% and 50%) were added again.The athletic ability, plasma membrane integrity, acrosome integrity, apoptosis, mitochondrial membrane potential, protamine deficiency and in vitro capacitation level of Landrace boar sperm after freezing and thawing were evaluated.【Result】 Compared with control group (no HSPA8 and sperm plasma), in 0.5 μg/mL HSPA8 treatment group (no sperm plasma), the sperm kinetic parameters VSL, VCL, VAP and STR were significantly increased (P < 0.05), and LIN and WOB were not significantly different (P > 0.05), the sperm quality parameters such as sperm motility, plasma membrane integrity and acrosome integrity were significantly increased (P < 0.05), the sperm apoptosis level and mitochondrial membrane potential were significantly reduced (P < 0.05), the sperm protamine deletion rate was significantly decreased (P < 0.05), the tyrosine phosphorylation level of sperm protein was significantly increased (P < 0.05).After that, adding different concentrations of seminal plasma treatment group to the thawing solution, compared with 0.5 μg/mL HSPA8 treatment group (no seminal plasma), when the amount of seminal plasma reached 50%, VSL, VCL, VAP, LIN, STR and WOB were significantly increased (P < 0.05), the sperm motility, plasma membrane integrity, acrosome integrity and mitochondrial membrane potential were significantly increased (P < 0.05), the sperm apoptosis level was significantly reduced (P < 0.05), the sperm protamine deletion rate was significantly decreased (P < 0.05), the tyrosine phosphorylation level of sperm protein was significantly increased (P < 0.05).【Conclusion】 In conclusion, the combination of adding 0.5 μg/mL HSPA8 to the freezing base solution and adding 50% seminal plasma to the thawing diluent could effectively improve the quality of frozen-thawed sperm, which would provide certain reference value for the cryopreservation and commercial production of boar semen.

Key words: boar sperm; heat shock protein A8 (HSPA8); seminal plasma (SP); frozen-thawed; quality parameters