Evaluation of sperm kinematics, physical integrity and malondialdehyde levels as indicators of sperm freezability in Pradu Hang Dam chicken.

The widespread application of semen cryopreservation in indigenous poultry conservation is limited by high individual variability in freezability, which dictates overall post thaw sperm quality and fertilizing potential of cryopreserved sperm. The aim of this study was to identify the physical, kinematic, and biochemical characteristics that differentiate Pradu Hang Dam Chickens' good freezable (GF; n = 11) and bad freezable (BF; n = 11) ejaculates. Pre- and post-thaw total motility, sperm kinematics (computer-assisted sperm analysis - CASA), viability (SYBR-14/PI), plasma membrane functionality (hypo-osmotic swelling test; HOST), and lipid peroxidation (malondialdehyde; MDA) were all assessed on cryopreserved semen samples. The GF ejaculates exhibited significantly higher total motility (P < 0.0001), viability (P < 0.0001), and HOST-reactivity (P < 0.0001) compared to the BF group. Notably, CASA reported no significant differences in the kinematic parameters of the groups' surviving motile subpopulations, indicating that cryopreservation serves as an extreme functional filter. According to biochemical examination, BF ejaculates had significantly higher levels of oxidative stress, as indicated by enhanced post-thaw MDA levels (P < 0.0001). Correlation analysis demonstrated largely conserved relationships among sperm quality traits in both groups. Fisher's r-to-z comparisons identified only a limited number of nominal differences in individual correlations, primarily involving membrane functionality and motility related variables. Collectively, these findings indicate that poor sperm freezability in Pradu Hang Dam chickens is primarily associated with increased susceptibility to oxidative stress and compromised membrane integrity rather than intrinsic differences in the kinematic performance of surviving spermatozoa. These results highlight membrane protection and oxidative stress mitigation as promising targets for improving cryopreservation outcomes in indigenous chicken genetic resources.