Effect of the addition of IGF-1 during in vitro culture on the embryonic development speed from different crossbreed bovine embryos.

Supplementation with insulin-like growth factor type 1 (IGF-1) during in vitro culture of bovine embryos has yielded mixed results, likely due to genetic variability among embryos. This work aimed to evaluate the effect of IGF-1 at two concentrations on the development speed embryos from primary F1 crossbreeds used in dual-purpose cattle farming in the Colombian low tropics. Specifically, we investigated the influence of IGF-1 and embryo breed on the blastocyst formation rate. Oocytes were sourced from non-pregnant cows: Bos taurus indicus (20 Brahman and 14 Gyr) and Bos taurus taurus (12 Holstein and 28 Romosinuano). Oocytes were fertilized with semen from specific bulls (Recoil for Holstein, Gabinete for Gyr, and UBER POI 1490 for Brahman). The resulting embryos from each crossbreed group were randomly distributed in three different cultured media with 50 ng/mL IGF-1, 100 ng/mL IGF-1, or no IGF-1 (control) for 7 days. Results showed that 50 ng/mL IGF-1 significantly increased embryo production by day 6 (25.9%±14.56%) compared to control (20.5%±11.84%) and 100 ng/mL IGF-1 (23.0%±9.54%) (p < 0.05). By day 7, both 50 ng/mL (42.6%±26.55%) and 100 ng/mL (49.7%±21.98%) IGF-1 groups exhibited significantly higher production rates compared to the control group (p < 0.001). The embryo breed also influenced development, with Gyr-Holstein (GxH) crossbreeds showing the highest production rates (p < 0.001). In conclusion, IGF-1 supplementation enhances in vitro embryo production, with the effect influenced by both breed and IGF-1 concentration. These findings suggest that breed-specific optimization of IGF-1 conditions is necessary to maximize embryonic development outcomes.