A Low Concentration of a Sustainably Obtained Blueberry Extract Improves the Post-Thawing Motility of Cryopreserved Bull Spermatozoa.

Natural extracts could improve sperm storage and artificial insemination (AI). This study, for the first time, evaluates the suitability of a blueberry extract (Vaccinium corymbosum), obtained from pomace using a sustainable methodology, as a supplement for bull semen extenders. Cryopreserved semen doses from eight bulls were combined in 9 pools (3 bulls/pool), supplemented with 0%, 1%, 5%, or 10% extract and incubated up to 5 h at 38°C. Motility was assessed hourly using OpenCASA, and the effects of treatment and time were evaluated using linear mixed-effects models. Motility was significantly better preserved with 1% extract (total and progressive motility, linear velocity and linearities, with lower BCF and fractal dimension, related to hyperactivation). The effect of 5% was overall positive but lower than 1%, whereas 10% showed a mostly negative effect. This natural extract could safely supplement bull semen extenders by at least 5% and even help improve sperm motility. Therefore, its use as a supplement in bull semen extenders offers an opportunity to enhance assisted reproductive techniques in cattle using a sustainable approach.