[Effect of docosahexaenoic acid and Trolox® in extenders for cooling semen from Mangalarga Marchador stallion]

ABSTRACT The objective of this study was to evaluate the effect of docosahexaenoic acid (DHA), associated or not with Trolox®, in extenders for cooling semen from Mangalarga Marchador stallions. Ten ejaculates were cooled in the following diluents: D1) BotuSemen® (BS; control); D2) BS + 30ngmL-1 DHA (BS30DHA); D3) BS30DHA + 40μM Trolox® (BS30DHA40T); D4) BS + 50ngmL-1 DHA (BS50DHA); D5) BS50DHA + 40μM Trolox® (BS50DHA40T). After 48 hours of refrigeration, the sperm movement, structural and functional integrity of the plasma membrane and sperm longevity were evaluated. All extenders tested similarly preserved motility, linearity, straightness of trajectory, amplitude of lateral head displacement, beat cross frequency, hyperactive, the structural and functional integrity of the sperm membrane (P> 0.05). The BS50DHA extender was superior to BS30DHA40T in preserving VCL and VSL and was superior to BS30DHA40T and BS50DHA40T in preserving VAP and oscillation index (P< 0.05). It is concluded that the use of Trolox® in extenders for cooling stallion sperm containing docosahexaenoic acid at the proposed concentrations is not indicated because it alters sperm movement parameters considered important for fertility.