ABCG2 and fetal growth restriction: The ABC transporter pathway was enriched in NBW pigs compared to that in IUGR pigs in the 25 and 50 kg BW groups, and phenylalanine, tyrosine, and tryptophan biosynthesis and energy metabolism pathways were enriched in NBW pigs compared to that in IUGR pigs in the 25 and 100 kg BW groups (Fig. 9).