Dietary antioxidant supplementation improves the in vitro quality and antioxidant capacity of Colombian Creole stallion semen

Dietary antioxidant supplementation has become popular for managing male infertility because of its impact on the antioxidant capacity of semen. This study evaluates the effect of dietary antioxidant supplementation on the seminal characteristics of Colombian Creole horses. Semen from six Colombian Creole stallions was collected using an artificial vagina. The stallions were randomly allocated to a control group (CG) or a supplementation group (SG) that received a multi-antioxidant supplement. A repeated measures design, with a wash out period of two weeks between treatments, was used. Sperm motility and kinematics were assessed using a computer-assisted semen analysis system, membrane integrity (MI) and the acrosomal integrity (AI) of sperm were assessed using fluorescent microscopy, abnormal morphology (AM) was analysed using supravital staining, and the functionality of the sperm membrane was assessed using the hypoosmotic swelling (HOS) test. A fraction of each ejaculate sample was centrifuged to obtain seminal plasma (SP). The reactive oxygen species and the total antioxidant capacity (TAC) of the SP were measured via spectrofluorimetry. Linear models were fitted, and comparison of means was performed using Tukey's test. Dietary antioxidant supplementation increased sperm beat cross frequency. In addition, a higher AI was found for the SG. Supplementation also increased the TAC of the SP. Individual analysis revealed that dietary antioxidant supplementation increased the total and progressive motility of the semen of two horses in the SG; however, supplementation reduced these two parameters in two other individuals compared to the CG. It can be concluded that dietary antioxidant supplementation with a nutraceutical that provides vitamins, minerals, amino acids, and omega-3 for horses can increase sperm quality as well as the TAC of SP; however, this may be subject to the individual effect of each horse.