The Critical Functions of FGF2, LIF and IGF1 in the Improvement of In Vitro Embryo Production

In vitro embryo production (IVP) has emerged as a crucial tool in assisted reproduction and animal biotechnology. A key factor in this process is in vitro oocyte maturation (IVM), a critical process preceding fertilization that directly influences embryo quality. FLI supplementation, composed of fibroblast growth factor (FGF2), leukemia inhibitory factor (LIF), and insulin-like growth factor 1 (IGF1), has been shown to facilitate the IVM process to mimic essential aspects of in vivo oocyte development, and therefore, promote higher rates of oocyte maturation, embryonic viability, blastocyst formation, and improve the number of live animals born after embryo transfer. Individually or together, these components participate in signaling pathways that are crucial for improving oocyte competence and early embryo development. This review highlights the individual and combined roles of FGF2, LIF, and IGF1 in maturation and embryo culture medium, their influence on subsequent embryonic development, and their signaling pathways. Additionally, the incorporation of antioxidants and amino acids as supplementary components in combination with FLI is explored as a strategy to mitigate oxidative stress and enhance metabolic support during IVM and embryo culture. Together, these elements can significantly improve IVP outcomes, providing a potential pathway for optimizing the efficiency of embryo production in various species.