Regulatory role for l-arginine in the utilization of amino acids by pig small-intestinal bacteria

Abstract

We recently reported that bacteria from the pig small intestine rapidly utilize and metabolize amino acids (AA). This study investigated the effect of L-arginine on the utilization of AA by pure bacterial strains (Streptococcus sp., Escherichia coli and Klebsiella sp.) and mixed bacterial cultures derived from the pig small intestine. Bacteria were incubated at 37°C for 3 h in anaerobic AA media containing 0-5 mmol/L of arginine to determine the effect of arginine on the bacterial utilization of AA. Amino acids in the medium plus cell extracts were analyzed by high-performance liquid chromatography. Results indicated concentration-dependent increases in the bacterial utilization of arginine and altered fluxes of arginine into ornithine and citrulline in the bacteria. Net glutamine utilization increased in pure bacterial strains with increased concentrations of arginine. With the addition of arginine, net utilization of threonine, glycine, phenylalanine and branched-chain AA increased (P<0.05) in Streptococcus sp. and Klebsiella sp., but decreased in E. coli. Net utilization of lysine, threonine, isoleucine, leucine, glycine and alanine by jejunal or ileal mixed bacteria decreased (P<0.05) with the addition of arginine. Complete utilization of asparagine, aspartate and serine were observed in pig small-intestinal bacteria after 3 h of incubation. Overall, the addition of arginine affected the metabolism of the arginine-family of AA and the serine- and aspartate-family of AA in small-intestinal bacteria and reduced the utilization of most AA in ileal mixed bacteria. These novel findings indicate that arginine exerts its beneficial effects on swine nutrition partially by regulating AA utilization and metabolism in the small-intestinal microbiota.

Co-dependence of genotype and dietary protein intake to affect expression on amino acid/peptide transporters in porcine skeletal muscle

“…Plasma AA concentrations are affected by a variety of factors, including intracellular protein synthesis and degradation in tissues, AA transport and metabolism, and intestinal microbiota activity (Blachier et al 2007;Dai et al 2011Dai et al , 2012Dai et al , 2013. There is evidence that the pig small intestine extensively catabolizes AA in a segment-dependent manner (Dai et al 2015;Yang et al 2014) such that nearly 50 % of total dietary AA (the sum of all AA) do not enter the portal circulation.…”

Dietary essentiality of “nutritionally non-essential amino acids” for animals and humans

“…34 Likewise, arginine decreases the net utilization of threonine, glycine, phenylalanine, and branched-chain AA by intestinal E. coli, and of lysine, threonine, isoleucine, leucine, glycine, and alanine by jejunal or ileal mixed bacteria. 35 These findings indicate that glutamine and arginine exert their beneficial effects on nutrition and the metabolic status partly by regulating AA utilization and metabolism in the small-intestinal microbiota.…”

Dietary supplementation with l-glutamate and l-aspartate alleviates oxidative stress in weaned piglets challenged with hydrogen peroxide

“…Based on the studies with glutamine, arginine (Dai et al 2012(Dai et al , 2015, and glutamate (Rezaei et al 2013b), we surmise that increased availability of Glu or Asp in diets may inhibit the catabolism of amino acids (including Lys) in the small-intestinal bacteria. Therefore, together with the data on growth performance, we suggest that the restoration of amino acid profiles in the blood of Glu-or Asp-supplemented piglets plays an important role in alleviating H 2 O 2 -induced growth suppression.…”