Vol.:(0123456789) 1 3 Amino Acids https://doi.org/10.1007/s00726-018-2586-7 ORIGINAL ARTICLE Dietary supplementation with an amino acid blend enhances intestinal function in piglets Dan Yi 1  · Baocheng Li 1  · Yongqing Hou 1  · Lei Wang 1  · Di Zhao 1  · Hongbo Chen 1  · Tao Wu 1  · Ying Zhou 1  · Binying Ding 1  · Guoyao Wu 1,2 Received: 7 March 2018 / Accepted: 11 May 2018 © Springer-Verlag GmbH Austria, part of Springer Nature 2018 Abstract The traditionally classified nutritionally non-essential amino acids are now known to be insufficiently synthesized for maximal growth and optimal health in piglets. This study determined the effects of dietary supplementation with an amino acid blend (AAB; glutamate:glutamine:glycine:arginine:N-acetylcysteine = 5:2:2:1:0.5) on piglet growth performance and intestinal functions. Sixteen piglets (24-day-old) were randomly assigned to a corn and soybean meal-based diet supplemented with 0.99% alanine (isonitrogenous control) or 1% AAB. On day 20 of the trial, blood and intestinal tissue samples were obtained from piglets. Compared with the control, AAB supplementation reduced (P < 0.05) diarrhoea incidence; plasma alanine aminotransferase and diamine oxidase activities; intestinal concentrations of hydrogen peroxide, malondialdehyde, and heat shock protein-70, and intestinal mRNA levels for interleukin-1β, interferon-γ, and chemokine (C–X–C motif) ligand-9; and the numbers of Enterobacterium family, Enterococcus genus and Clostridium coccoides in the colon digesta. Furthermore, AAB supplementation enhanced (P < 0.05): the plasma concentrations of serine, aspartate, glutamate, cysteine, tyrosine, phenylalanine, tryptophan, lysine, arginine, citrulline, ornithine, taurine, and γ-aminobutyric acid; intestinal villus height and surface area, villus height/crypt depth ratio, antioxidative enzyme activities, and mRNA levels for porcine β-defensin-1, sodium-independent amino acid transporters (b 0,+ AT and y + LAT1), aquaporin (AQP) 3, AQP8, AQP10, nuclear factor erythroid 2-related factor 2 and glutathione S-transferase omega-2, and protein abundances of AQP3, AQP4, claudin-1, occludin and myxovirus resistance 1; and the numbers of Bifidobacterium genus and Lactobacillus genus in the colon digesta. Collectively, these comprehensive results indicate that dietary AAB supplementation plays an important role in improving piglet growth and intestinal function. Keywords Amino acid blend · Intestinal function · Piglets Abbreviations AAB Amino acid blend AQP Aquaporin b 0,+ AT Sodium-independent amino acid transporter CXCL Chemokine (C–X–C motif) ligand LAT1 L-type amino acid transporter 1 NEAA Nutritionally non-essential amino acids TBST Tris-buffered saline with Tween 20 Introduction A major challenge in the global swine industry is to control piglet diarrhoea and maximize the genetic potential of pig growth. Diarrhoea results from intestinal dysfunction, lead- ing to loose or watery stools due to excessive water in the bowel. With the worldwide banning of the use of in-feed antibiotics (that can minimize the incidence of diarrhoea) in animal production, it is urgent to seek potential alterna- tives to the antibiotics for the sustainable development of the Handling Editor: F. Blachier. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00726-018-2586-7) contains supplementary material, which is available to authorized users. * Yongqing Hou houyq@aliyun.com 1 Hubei Collaborative Innovation Center for Animal Nutrition and Feed Safety, Hubei Key Laboratory of Animal Nutrition and Feed Science, Wuhan Polytechnic University, Wuhan 430023, China 2 Department of Animal Science, Texas A&M University, College Station, TX 77843, USA