Oxidative stress induced by cryopreservation reduces sperm quality, hindering preservation of the superior germ plasm. This study aimed to evaluate the effects of selenium nanoparticles (SeNPs) and sodium selenite (Na₂SeO₃) supplementation into semen extender on post-thaw semen quality of Madura bulls. Eight ejaculates were obtained from four bulls over a two weeks period. In the first week, semen was collected twice from two bulls. In the second week, two ejaculates were collected from the remaining two bulls. Following preliminary screening, collected ejaculates were cryopreserved using skim milk-egg yolk-glycerol extender supplemented with SeNPs and Na₂SeO₃ at concentrations of 0 (control), 5, 10 and 25ppm and stored in liquid nitrogen (LN₂) for 90 days. Post-thaw semen quality was evaluated using CASA for kinematic motility parameters, as well as microscopic assessment of sperm viability, morphological abnormalities, plasma membrane integrity (PMI), acrosomal membrane integrity (AMI), and oxidative parameters, such as reactive oxygen species (ROS), malondialdehyde (MDA) and catalase activity (CAT). Both types of selenium and their concentrations improved sperm motility, viability, PMI, AMI, and oxidative markers (P≤0.05), but did not affect sperm abnormalities compared to the control. Supplementation of SeNPs (5ppm) provided the best sperm quality in terms of motility, viability, PMI and AMI. The higher Na₂SeO₃ dose (25ppm) was associated with increased levels of oxidative markers. However, this condition was not observed in the SeNPs group. In general, all SeNPs doses showed good efficacy by reducing ROS and MDA levels, with increasing CAT activity, indicating superior redox modulation compared to Na₂SeO₃. In conclusion, SeNPs at 5ppm represents an optimal, non–pro-oxidant dose for improving post-thaw quality of Madura bull semen, and offers a promising strategy for Indonesian local cattle cryopreservation programs.

To Cite This Article: Widayati DT, Diatmono DFF, Padmawati FG, Sitaresmi PI, Kusumawati A and Pangestu M, 2026. Nano-selenium supplementation of semen extender improves post-thaw semen quality of Indonesian local Madura bulls: A preliminary study. Pak Vet J, 46(7): 1819-1827. http://dx.doi.org/10.29261/pakvetj/2026.175