Functional Amino Acids in Pigs and Chickens: Implication for Gut Health

In pigs and broiler chickens, the gastrointestinal tract or gut is subjected to many challenges which alter performance, animal health, welfare and livability. Preventive strategies are needed to mitigate the impacts of these challenges on gut health while reducing the need to use antimicrobials. In the first part of the review, we propose a common definition of gut health for pig and chickens relying on four pillars, which correspond to the main functions of the digestive tract: (i) epithelial barrier and digestion, (ii) immune fitness, (iii) microbiota balance and (iv) oxidative stress homeostasis. For each pillar, we describe the most commonly associated indicators. In the second part of the review, we present the potential of functional amino acid supplementation to preserve and improve gut health in piglets and chickens. We highlight that amino acid supplementation strategies, based on their roles as precursors of energy and functional molecules, as signaling molecules and as microbiota modulators can positively contribute to gut health by supporting or restoring its four intertwined pillars. Additional work is still needed in order to determine the effective dose of supplementation and mode of administration that ensure the full benefits of amino acids. For this purpose, synergy between amino acids, effects of amino acid-derived metabolites and differences in the metabolic fate between free and protein-bound amino acids are research topics that need to be furtherly investigated

Influence of dietary supplementation with an amino acid mixture on inflammatory markers, immune status and serum proteome in lps-challenged weaned piglets

In order to investigate the effect of a dietary amino acid mixture supplementation in lipopolysaccharide (LPS)-challenged weaned piglets, twenty-seven 28-day-old (8.2 ± 1.0 kg) newly weaned piglets were randomly allocated to one of three experimental treatments for five weeks. Diet 1: a CTRL treatment. Diet 2: an LPS treatment, where piglets were intraperitoneally administered LPS (25 µg/kg) on day 7. Diet 3: an LPS+MIX treatment, where piglets were intraperitoneally administered LPS on day 7 and fed a diet supplemented with a mixture of 0.3% of arginine, branched-chain amino acids (leucine, valine, and isoleucine), and cystine (MIX). Blood samples were drawn on day 10 and day 35, and serum was analysed for selected chemical parameters and proteomics. The LPS and LPS+MIX groups exhibited an increase in haptoglobin concentrations on day 10. The LPS group showed an increased cortisol concentration, while this concentration was reduced in the LPS+MIX group compared to the control group. Similarly, the LPS+MIX group showed a decreased haptoglobin concentration on day 35 compared to the two other groups. Immunoglobulin concentrations were affected by treatments. Indeed, on day 10, the concentrations of IgG and IgM were decreased by the LPS challenge, as illustrated by the lower concentrations of these two immunoglobulins in the LPS group compared to the control group. In addition, the supplementation with the amino acid mixture in the LPS+MIX further decreased IgG and increased IgM concentrations compared to the LPS group. Although a proteomics approach did not reveal important alterations in the protein profile in response to treatments, LPS-challenged piglets had an increase in proteins linked to the immune response, when compared to piglets supplemented with the amino acid mixture. Overall, data indicate that LPS-challenged piglets supplemented with this amino acid mixture are more protected against the detrimental effects of LPS.This study was supported by Ajinomoto Animal Nutrition Europe, by Indukern Portugal, Lda., and by Fundação para a Ciência e a Tecnologia (FCT, Lisbon, Portugal) through projects UIDB/CVT/00276/2020 to CIISA and PEST/UID/AGR/4129/2020 to LEAF. It was also supported by national funds, through FCT Stimulus of Scientific Employment Program to author P.A.L. (DL57/2016/CP1438/CT0007) and a Ph.D. grant (SFRH/BD/143992/2019) to author D.M.R. This work had the support from the Portuguese Mass Spectrometry Net-work, integrated in the National Roadmap of Research Infrastructures of Strategic Relevance (ROTEIRO/0028/2013; LISBOA-01-0145-FEDER-022125)

Tryptophan requirements of growing pigs: a dose response study

A total of 144 pigs were divided into four dietary treatment groups with increasing tryptophan:lysine ratios (apparent ileal digestible (AID) Trp:Lys 0:14, 0:17, 0:20 and 0:23 and standardized ileal digestible (SID) Trp:Lys 0:15, 0:18, 0:21 and 0:24) for 6 weeks. There were 6 replicates with 6 animals per replicate in each treatment. It was shown that increasing dietary AID Trp:Lys from 0:14 to 0:20 significantly stimulated feed intake from 1.2 to 1.6 kg/day, liveweight gain from 509 to 752 g/day and body weight at the end of the experiment from 44.2 to 56.6 kg. Feed conversion ratio was reduced from 2.49 to 2.15. AID and SID Trp:Lys requirements for maximum liveweight gain were estimated at 0.19 and 0.22 and 0.20 and 0.23 using linear plateau and quadratic models, respectively