Sperm quality is improved feeding stallions with a rice oil supplement

Abstract

Triglycerides are essential for sperm metabolism and high levels of triglycerides are associated with good semen quality. The level of polyunsaturated fatty acids (PUFAs) is considered critical for capacitation and is associated with sperm motility and increased membrane fluidity. The aim of this experiment was to evaluate the effects of supplementary feeding of stallions with commercial rice oil (Gama-Horse, HT Nutri®, Brazil) on sperm parameters. This supplement has been used for many years has been reported to improve semen quality. Four stallions with ages ranging between 6 and 30 years were used. The animals were managed similarly during the 190 days of the trial. The experiment was divided in three periods: pre-treatment (PT)—30 days to stabilize sperm reserves; treatment (TR)—80 days of supplementation with 200 mL rice oil containing 34% linoleic acid, 1% linolenic acid, 1% gamma oryzanol and vitamin E; control (CN)—80 days without rice oil supplementation. Ejaculates were collected twice a week with an artificial vagina. Semen examinations were performed immediately after collection: volume, concentration, total motility, hypo-osmotic test (HOST) evaluating functionality, carboxyfluorescein diacetate/propidium iodide (CFDA/PI) evaluating membrane integrity and total antioxidant potential (TRAP). A blood sample was obtained each 15 days to evaluate plasma testosterone and estradiol. To evaluate the effect of the rice oil supplementation, the semen data from the last 20 days of TR and from the last 20 days of CN were analyzed with ANOVA, differences being statistically significant if P< 0.05. The supplementation of rice oil increased concentration (P< 0.01) (TR: 226× 106 mL−1; CN: 172× 106 mL−1), total motility (P< 0.01) (TR: 59%; CN: 42%), HOST (P< 0.02) (TR: 73%; CN: 69%) and TRAP (P< 0.01) (TR: 1.9 nmol Trolox/mg of protein; CN: 0.98 nmol Trolox/mg of protein). No differences between periods of TR and CN were observed in volume, membrane integrity, testosterone or estradiol. Oral supplementation with the commercial rice oil containing PUFA and gamma-oryzanol increased the total antioxidant potential of the semen. In addition, higher membrane functionality and motility was detected, possibly due to antioxidant protection preventing lipid peroxidation of sperm membranes or due to improved membrane fluidity.