Linking the Degree of Intrauterine Growth Restriction to Alterations in Metabolism, Energy Reserves, and Gut Health in Newborn Piglets

Lay Summary

Piglets with intrauterine growth restriction (IUGR) negatively affect overall swine production efficiency, as they exhibit stunted postnatal growth, reduced feed conversion efficiency, and poorer carcass quality. Classifying piglets at birth according to their degree of IUGR enables farmers to implement targeted strategies for the subset of pigs at higher risk. In this study, piglets were classified based on their birth weight (BtW) into four categories: IUGR, restricted low BtW (R-LBW), non-restricted low BtW (NR-LBW), and normal (N). Overall, IUGR piglets were lighter at birth and showed impaired growth throughout lactation. This growth retardation could be attributed to low vitality and reduced colostrum intake, metabolic alterations affecting amino acid and energy metabolism, gastrointestinal dysfunction characterized by altered morphology and upregulation of pro-inflammatory and stress-related genes, and limited energy reserves. Piglets classified as R-LBW and NR-LBW also exhibited reduced growth performance compared to N piglets and displayed distinct morphological characteristics, although few differences were observed in internal traits between the two categories. Understanding the biological challenges faced by IUGR and low BtW piglets, as well as how to differentiate them, could help farmers improve survival, growth, and overall health, ultimately enhancing farm efficiency and animal welfare.