摘要Background Chinese indigenous pigs are popular with consumers for their juiciness,flavour and meat quality,but they have lower meat production.Insulin-like growth factor 2(IGF2)is a maternally imprinted growth factor that promotes skeletal muscle growth by regulating cell proliferation and differentiation.A single nucleotide polymor-phism(SNP)within intron 3 of porcine IGF2 disrupts a binding site for the repressor,zinc finger BED-type containing 6(ZBED6),leading to up-regulation of IGF2 and causing major effects on muscle growth,heart size,and backfat thick-ness.This favorable mutation is common in Western commercial pig populations,but absent in most Chinese indig-enous pig breeds.To improve meat production of Chinese indigenous pigs,we used cytosine base editor 3(CBE3)to introduce/GF2-intron3-C3071T mutation into porcine embryonic fibroblasts(PEFs)isolated from a male Liang Guang Small Spotted pig(LGSS),and single-cell clones harboring the desired mutation were selected for somatic cell nuclear transfer(SCNT)to generate the founder line of IGF2T/T pigs.Results We found the heterozygous progeny IGF2C/T pigs exhibited enhanced expression of IGF2,increased lean meat by 18％-36％,enlarged loin muscle area by 3％-17％,improved intramuscular fat(IMF)content by 18％-39％,marbling score by 0.75-1,meat color score by 0.53-1.25,and reduced backfat thickness by 5％-16％.The enhanced accumulation of intramuscular fat in IGF2C/T pigs was identified to be regulated by the PI3K-AKT/AMPK pathway,which activated SREBP1 to promote adipogenesis.Conclusions We demonstrated the introduction of/GF2-intron3-C3071T in Chinese LGSS can improve both meat production and quality,and first identified the regulation of IMF deposition by IGF2 through SREBP1 via the PI3K-AKT/AMPK signaling pathways.Our study provides a further understanding of the biological functions of IGF2 and an example for improving porcine economic traits through precise base editing.