Porcine somatic cell nuclear transfer donor sources affect transplant success: A meta-analysis

Herd boars, male domestic pigs used for stud, are economically important, and somatic cell nuclear transfer (SCNT) is a promising technology to expand herd boar yields. However, live births are dictated by donor cell source, and fetal donors may offer more advantages than adult donors. A meta-analysis was conducted to better understand how donor sources affect SCNT outcomes. Of the 1,431 records viewed, 10 were selected for review. Blastocyst formation rates, successful pregnancies, and live births were assessed to measure efficacy. SCNT blastocyst formation differed between adult and fetal donors among the studies. SCNT pigs had more malformed fetuses as well, which negatively affected the post-birth mortality. Organs of porcine fetuses are limited by deficiencies of maternal nutrient and growth hormones, which compromise post-birth adaptations. SCNT pregnancy success is neither determined by donor source nor by live births. Live births are also tied to donor age. Embryos from fetal donors are more frequently healthy likely due to less differentiation and less reprogramming of reconstructed embryos. Adult donors in contrast have more cell differentiation and as such accumulate more mutations and damage. This may reduce reconstructed embryo viability. Finally, SCNT efficiency may be improved with more in vitro passages, but more work is required to validate this concept.