Abstract

The Gaga chicken is an indigenous Indonesian breed that is important to preserve using semen cryopreservation technology. The study was conducted to determine the effect of adding sorbitol and butylated hydroxytoluene (BHT) in the diluent on the structural and surface ultrastructure of cryopreserved Gaga chicken sperm during cryopreservation/frozen storage. The study aimed to assess how adding sorbitol and butylated hydroxytoluene (BHT) to the diluent affects the structure and surface ultrastructure of cryopreserved Gaga chicken sperm. A completely randomized design was employed with four treatments and 10 replications including egg yolk-lactate ringer diluent (EYLR) as the control group, EYLR diluent with 3 mM BHT, EYLR diluent with 2 sorbitol, and EYLR diluent with both 3 mM BHT and 2 sorbitol. Semen was collected using a massage technique from 4 male chickens aged approximately 10 months, pooled semen was diluted, packaged in 0.25 mL straws, equilibrated for 2 hours at 5 °C, pre-freeze for 10 minutes, frozen for 24 hours, and thawed for 30 seconds at 37 °C. The parameters evaluated were sperm plasma membrane integrity, acrosome integrity, DNA damage, mitochondrial functionality, and surface ultrastructure. The results showed that the treatment had a significant effect on plasma membrane integrity and post-thawing mitochondrial functionality compared to the control, but no effect was observed on acrosome integrity or DNA damage. The results showed that the combination treatment of BHT with sorbitol had a significant effect on plasma membrane integrity and post-thawing mitochondrial function, but did not affect acrosome integrity or DNA damage when compared to the control group. Ultrastructural observations indicated that cryopreservation caused damage to the head, middle, and tail of the sperm in the control groups. However, these changes were prevented by the diluent containing a combination of BHT and sorbitol. The addition of both components (BHT 3 mM + sorbitol 2) effectively maintained plasma membrane integrity, mitochondrial functionality, and surface ultrastructure of Gaga chicken sperm during cryopreservation. © The Author(s) 2024