Curcumin-Treated Bull Semen Leaves IVF Outcomes Unchanged in Bovine Study

Adding curcumin extract to thawed bull semen did not harm in vitro fertilization outcomes, according to a brief report published in Acta Veterinaria Scandinavica. Researchers found no statistically significant differences between curcumin-treated and control semen in cleavage rate, the proportion of oocytes developing beyond the two-cell stage, or blastocyst formation on day 8, suggesting that the spice-derived compound does not impair the fertilizing capacity of bull sperm under the conditions tested.

The study, conducted by Aleksandar Cojkic, Olga Sajecka, Ylva Sjunnesson and Jane M. Morrell, set out to address a gap in reproductive biotechnology. Curcumin, the major biologically active polyphenol in turmeric (Curcuma longa), has previously shown antioxidant and antibacterial properties in bull semen at a concentration of 5 percent, but its impact on fertilization outcomes had remained largely unexplored. Because semen processing and cryopreservation expose spermatozoa to oxidative, osmotic, thermal and mechanical stresses that can damage membranes, motility, mitochondrial activity and DNA integrity, safe additives that protect sperm function during preservation are a key research objective.

The experimental design relied on abattoir-derived bovine ovaries transported to the laboratory within five hours. Cumulus-oocyte complexes were aspirated from follicles three to eight millimeters in diameter, graded for quality, and randomly assigned to treatment or control groups before maturation. Five ovary replicates were performed, each split into two groups of roughly 30 oocytes, which were matured for 22 hours in Stroebech Media at 38.5 degrees Celsius under 6 percent carbon dioxide.

Fertilization used frozen-thawed semen from a single Swedish Red dairy bull with proven field and in vitro fertility. Treatment aliquots were incubated at room temperature with a 5 percent curcumin extract for 30 minutes after thawing, while control aliquots received the corresponding volume of diluted ethanol solvent. The curcumin solution was prepared by dissolving 5 milligrams of curcumin in 500 microliters of 70 percent ethanol, diluting to 15 milliliters with peptone water to reach 667 micrograms per milliliter, centrifuging, and using the supernatant for semen supplementation. The 5 percent concentration was chosen because prior work had shown it reduces bacterial load without compromising sperm quality.

A key methodological choice was the sperm concentration. The team deliberately reduced the insemination dose to 0.5 million spermatozoa per milliliter, half the one million per milliliter recommended by the media manufacturer, to prevent a large excess of sperm from masking any treatment effects. Each fertilization dish contained two wells with curcumin-treated sperm and two control wells in random order, with a final volume of 500 microliters per well. Cleavage was assessed 44 hours after fertilization, and embryo development was evaluated on day 8, with blastocysts graded according to IETS guidelines and their nuclei counted after DAPI staining.

The results were unambiguous on the fertilization side. Cleavage rates were 51.97 plus or minus 13.58 percent in controls versus 50.25 plus or minus 10.89 percent with curcumin, a non-significant difference. The proportion of cleaved oocytes reaching more than two cells was 41.88 versus 50.94 percent, and the day-8 blastocyst rate from cleaved oocytes was 18.23 versus 19.87 percent, neither reaching significance. Mean blastomere counts on day 8 were also similar, at 74 plus or minus 26 in controls and 72 plus or minus 22 in the treated group. Total oocytes in maturation numbered 311 for the curcumin group and 317 for controls.

Sperm quality analyses told a more nuanced story. Computer-assisted sperm analysis of motility and kinematics showed no significant treatment effects, though trends toward significance emerged for total motility, which was higher in the curcumin-treated group, and for immotile spermatozoa, which were lower. Flow cytometry assessing membrane integrity, mitochondrial membrane potential via JC-1 staining, and chromatin integrity via the sperm chromatin structure assay found most viability parameters unchanged. The notable exception was mitochondrial membrane potential, which was significantly lower in curcumin-treated semen than in controls.

The authors interpret this mitochondrial finding cautiously. They note that cryopreservation itself induces mitochondrial damage through reactive oxygen species and membrane disruption, so pre-existing alterations in the frozen-thawed sperm may have been exacerbated by curcumin. They also point to prior studies suggesting curcumin can act as a pro-oxidant at higher concentrations and may interact with mitochondrial electron transport chain components. Timing matters as well: earlier work reporting improved mitochondrial membrane potential treated fresh semen with curcumin before cryopreservation, whereas this study applied the compound after thawing to already-damaged mitochondria.

The team acknowledges several limitations. Using semen from a single bull limits generalizability, since bull-to-bull variation in cryotolerance, mitochondrial function and fertilizing capacity can shape responses to supplementation, although the single-bull design minimized fertility variation within the IVF system. Testing only one concentration precludes dose-dependent analysis. The authors also note that cleavage and blastocyst rates in both groups were lower than typically reported in standard IVF protocols, and that slaughterhouse-derived oocytes from animals with varied hormonal, nutritional and physiological backgrounds, along with the reduced sperm concentration and the 30-minute room-temperature incubation, may all have contributed to the lower embryo development observed.

Overall, the study concludes that curcumin supplementation at the tested concentration does not impair the fertilizing ability of thawed bull spermatozoa, even though its effect on mitochondrial status warrants further investigation. The authors suggest future work should test different concentrations and exposure times, evaluate curcumin addition before freezing, explore nanotechnology-based formulations that improve curcumin’s low aqueous solubility and bioavailability, and ultimately assess the efficacy and safety of curcumin-treated semen in vivo, including effects on pregnancy rates and offspring health after artificial insemination.

Subject of Research: The effect of curcumin extract added to thawed bull semen on in vitro fertilization outcomes and sperm quality in cattle

Article Title: Curcumin extract addition to bull semen does not adversely affect in vitro fertilization

Article References: Cojkic, A., Sajecka, O., Sjunnesson, Y., & Morrell, J. M. (2026). Curcumin extract addition to bull semen does not adversely affect in vitro fertilization. Acta Veterinaria Scandinavica, 68(1), Article 47. https://doi.org/10.1186/s13028-026-00890-5

Image Credits: AI Generated

DOI: 10.1186/s13028-026-00890-5

Keywords: curcumin, bull semen, in vitro fertilization, bovine embryos, sperm motility, mitochondrial membrane potential, cryopreservation, flow cytometry, reproductive biotechnology, antioxidant, oocytes, blastocyst