Effect of lipopolysaccharide and zymosan on amino acid metabolism in chicks

1. This study investigated the metabolic effects of lipopolysaccharide (LPS, a pathogen-associated molecular pattern derived from gram-negative bacteria) and zymosan (a pathogen-associated molecular pattern derived from fungi) in young chickens (<i>Gallus gallus domesticus</i>).2. Liver RNA-seq analysis was performed on samples from chicks that received intraperitoneal injections of either LPS or zymosan. Pathogen-associated molecular patterns (PAMP) altered the expression of several genes associated with lipid, amino acid and carbohydrate metabolism in the liver. Moreover, both PAMP affected a common set of genes, with changes in their expression exhibiting a strong positive correlation (<i>R</i> ≥ 0.90). Subsequent analyses revealed that both PAMP altered plasma concentrations of several amino acids, including histidine.3. Finally, both PAMP significantly increased the mRNA expression of histidine decarboxylase and carnosine-N-methyltransferase, which are enzymes involved in the synthesis of histamine and anserine, respectively, in the liver and pectoralis major.4. These findings suggested that LPS and zymosan affect several metabolic pathways, particularly those related to amino acid metabolism and that they likely act through overlapping metabolic mechanisms.