Weaning-Induced Alterations to Sulfur Amino Acid Utilization in Pigs

Abstract

Weaning is one of the most stressful events for pigs. It is associated with low and variable feed intake, poor nutrient utilization, and high feed costs. A small percentage of weaned pigs do not ingest feed for several days post-weaning. Cysteine (Cys) is an important sulfur amino acid (SAA) and has key roles in pig production, but how Cys metabolism is modified by weaning is unclear. The objective of this study was to determine how a lack of feed intake alters SAA metabolism. Feed restriction at weaning alters cysteine utilization in a tissue-dependent manner. Specifically, glutathione (GSH) was depleted in the small intestine despite increased endogenous Cys availability from muscle protein breakdown. Impaired intestinal GSH production may negatively affect gut structure and function, leading to poor growth performance and increased morbidity and mortality during the immediate post-weaning period.