USING TRIBUTYRIN, A BUTYRATE PRODRUG, DURING GESTATION TO ALTER PERFORMANCE IN PIGS

Abstract

Prenatal and postnatal muscle growth and development occurs in a series of three waves. Every stage of the process requires the coordinated actions of myogenic precursor cells (MPC) or satellite cells (SC). Fetal programming of the muscle resident stem cells through maternal dietary intake is a potential method by which to influence muscle fiber growth throughout life. Butyric acid is a potent histone deacetylase (HDAC) inhibitor and has demonstrated strong effects on improving activation and differentiation of skeletal muscle satellite cells. It has also been implicated in serving as an important regulatory mechanism in intestinal cells. In animal models, this activity has resulted in direct promotion of muscle growth and improved resistance to pathogen induced illness. Whether butyrate supplementation during gestation can influence fetal and then lifelong muscle development has not yet been examined. Tributyrin, a pro-drug form of butyrate was utilized in all studies to address technical difficulties associated with using butyric acid as a feed supplement. In the first experiment, we aimed to investigate whether tributyrin at various concentrations in the sow diet could enhance fetal development and the degree to which inclusion levels might be most ideal (1% or 2% butyric acid). We found that tributyrin had a dose-dependent effect on fetal myogenic precursor cell activity and muscle structural organization. An increased proportion of primary fibers identified in the muscle of 2% treated fetal pigs indicated a greater capacity for an increased number of myofibers. Given these results, we repeated the gestational feeding study with more sows which were then allowed to farrow naturally with just one dietary level of tributyrin used (2%). Piglet tissues were collected between postnatal days 3 and 5, and sow milk samples were collected once on day 5 post farrowing to test the fatty acid composition. We found significant changes in the sow’s transition- milk in response to tributyrin. There was an indication of differences in expression of genes associated with SC differentiation in whole Longissimus dorsi (LD) muscle. However, there was no notable change in the muscle fiber size or numbers by day 3 or 5 post farrowing. In our final study, we performed a collaborative study with a contract research organization (CRO) based in the Midwest. This study followed the same design as our first two studies, but post-farrowing offspring growth was monitored. We saw significant improvements to pre-weaning average daily gains in tributyrin treated piglets. A subsample of gilts were selected once they reached 6 months of age for evaluation of carcass traits. Of those selected gilts, there was a significant reduction in overall fat accumulation. Future research is needed to confirm whether this is a universal response for pigs that had prenatal exposure to tributyrin. These findings help support the idea that prenatal tributyrin can enhance muscle growth and lifelong performance in pigs.