The Effects of Supplementing Oil and Leucine on Nutrient Transport in Sows, Muscle Development and Antioxidant Activity in Piglets

This study investigated the effects of dietary soybean oil and leucine (Leu) supplementation during the peripartum and lactating periods on placental nutrient transport, offspring muscle development, and antioxidant capacity in piglets. Sixty-eight gestating sows (Yorkshire × Landrace) were assigned to a 2 × 2 factorial design with two soybean oil levels (5% or 10% crude fat) and two Leu levels (0% or 1%). The results show that supplementation with oil, Leu, or both significantly increased muscle fibre diameter and cross-sectional area in the longissimus dorsi and biceps femoris, along with elevated muscle protein concentration and calcineurin (CaN) activity. Antioxidant status was improved in both the placenta and piglet muscles. In the placenta, oil and Leu upregulated the expression of VEGF-A and transporter genes for amino acids (SNAT2, SLC1A1, SLC7A1, SLC7A2, SLC7A8, and SLC7A11), glucose (GLUT1), and fatty acids (FABP2, FABP4, and FABP5). In the longissimus dorsi, they enhanced the expression of myogenic regulators (IGF1, IGF2, MYOD, and MYOG) and the slow-twitch fibre marker MyHC I. Notably, Leu also upregulated the expression of mTOR signalling pathway related genes in both the placenta and the longissimus dorsi. In conclusion, dietary supplementation with oil and Leu during the peripartum and lactating periods in sows enhanced placental nutrient transport, improved antioxidant capacity, and promoted muscle growth and slow-twitch fibre formation in piglets, providing a theoretical basis for optimising maternal nutritional regulation to promote placental function and offspring muscle development.