Effect of various concentrations of butylated hydroxyanisole and butylated hydroxytoluene on freezing capacity of Turkman stallion sperm

The present study aimed to determine the effect of different concentrations of butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) on post-thaw stallion sperm quality. The ejaculates collected from four healthy mature Turkmen stallions were pooled and divided into eight aliquots. The samples were diluted with extenders containing different concentrations (0.5, 1 or 2 mM/mL) of BHA or BHT. The positive control (PC) samples were diluted with extender containing 0.5% ethanol (v/v) whereas; the negative control (NC) samples were diluted with basic extender only. Semen samples were frozen according to a standard protocol. After thawing of samples, sperm motility, viability, membrane integrity, total abnormality and lipid peroxidation were assessed. The greatest (P < 0.05) values for total sperm motility, viability and plasma membrane functionality and least values for malonedialdehyde (MDA) concentration were observed in samples supplemented either with 1 mM BHT or 2 mM BHA. However, the progressive motility was greater (P < 0.05) only in samples treated with 2 mM BHA. In conclusion, the use of 1 mM BHT or 2 mM BHA in extender improves the freezing capacity of stallion sperm by reducing oxidative stress during freeze-thaw process.