Dietary Amino Acid Supplementation Research Articles

Dietary amino acid supplementation affects temporal expression of amino acid transporters and metabolic genes in selected and commercial strains of rainbow trout (Oncorhynchus mykiss).

Replacement of fishmeal as the major protein source in feeds is critical for continued growth and sustainability of the aquaculture industry. However, numerous studies have shown suboptimal fish growth performance and reduced protein retention efficiency when carnivorous fish species are fed low fishmeal-high plant protein feeds. A study was conducted using a commercial strain and a genetically improved strain of rainbow trout selected for improved performance when fed an all plant protein diet to identify physiological differences associated with growth performance in the selected trout strain. Fifty individuals per strain (average weight~580g) were force-fed a plant-protein blend with and without amino acid supplementation (lysine, methionine and threonine) at 0.5% body weight and sampled at intervals over 24h. Samples from intestine and liver were analyzed for specific gene expression analysis related to amino acid transporters, digestive process control, protein degradation and amino acid metabolism. The results showed that expression levels of various intestinal amino acid transporters (SLC1A1, SLC7A9, SLC15A, SLC1A5 SLC6A19 and SLC36A1) were affected by strain, diet and time. Moreover, significant interactions were found regarding the temporal expression levels of cholecystokinin (CCK-L), Krüppel-like factor 15 (KLF15) and aspartate aminotransferase (GOT) transcripts in the examined tissues. The results provide evidence that improved growth and protein retention of the selected strain fed an all-plant protein diet is a result of nutritional adaptation and an overall change in physiological homeostatic control.

Health economic burden of patients with phenylketonuria (PKU) – A retrospective study of German health insurance claims data

This retrospective matched-cohort analysis compared health-economic burdens of adults (≥18 years; n = 377) with phenylketonuria (PKU) and age/gender-matched non-PKU controls (n = 3770) in Germany. Healthcare costs and resource-utilization were analyzed for the year 2015. Differences between groups were tested using 95% CI of mean differences (MD). PKU patients had significantly higher mean costs in total (MD €3307, 95% CI €1736–€4879), for pharmaceuticals (MD €1912, 95% CI €1195–€2629) [including dietary amino-acid supplements (MD €1268, 95% CI €864–€1672)], and outpatient costs (MD €395, 95% CI €115–€675). Inpatient costs (MD €904, 95% CI -€293 to €2100) and costs for aids and remedies (MD €97, 95% CI -€10 to €203) were also higher in PKU patients. PKU patients had more outpatient visits and stayed longer in hospital. Adult PKU patients incur higher total healthcare costs than non-PKU controls, especially regarding pharmaceuticals and outpatient costs, and more frequent resource-utilization, resulting in higher health-economic burden for the statutory healthcare system.

210 A Longer Adaptation Period to a Functional Amino Acid-supplemented Diet Improves Growth Performance and Attenuates Acute-phase Response in Salmonella Typhimurium-challenged Pigs

Abstract Functional amino acid supplementation during disease challenge enhances growth performance and immune status. The present study investigated the effect of duration of adaptation period to a functional amino acid (FAA)-supplemented diet on growth performance and immune status during a subsequent Salmonella challenge in pigs. Thirty-two mixed-sex weanling pigs (8 pigs/treatment; 11.6 ± 0.34 kg initial body weight) received either a basal diet without FAA supplementation throughout the experimental period (FAA-) or a diet containing a supplemented FAA profile (Thr, Met, and Trp at 120% of requirements) fed for either 0 (FAA+0), 1 (FAA+1) or 2 (FAA+2) wk pre- and 1 wk post-inoculation with Salmonella Typhimurium (ST). Pigs were orally inoculated with saline containing ST after the 2 wk pre-inoculation period and monitored for 1 wk post-inoculation. Pigs had ad libitum access to diets throughout the experiment. Performance parameters [average daily gain (ADG), feed intake, and gain:feed (GF)] were measured in the pre- and post-inoculation periods. Blood samples were collected on d 0, 4, and 7 post-inoculation for serum haptoglobin and albumin analysis. There was no effect of diet on pre-inoculation performance (P > 0.05). Post-inoculation, FAA+2 pigs had the highest ADG (0.46 kg/d) and GF (0.63 kg/kg), FAA- the lowest (0.21 kg/d; 0.29 kg/kg), with FAA+0 (0.33 kg/d; 0.46 kg/kg) and FAA+1 (0.40 kg/d; 0.53 kg/kg) being intermediate (ADG, P < 0.05, SEM=0.059; GF, P < 0.05, SEM=0.099). Overall, albumin was higher in FAA+2 (35.25 g/L) and FAA+1 (34.63 g/L) pigs compared to FAA+0 (30.38 g/L) and FAA- (29.67 g/L) pigs (P < 0.05, SEM=0.717). Furthermore, FAA+2 pigs had the lowest overall haptoglobin (0.90 g/L), FAA- the highest (1.54 g/L), with FAA+0 (1.32 g/L) and FAA+1 (1.06 g/L) being intermediate (P < 0.05, SEM=0.111). In conclusion, a longer adaptation period to FAA supplementation improved performance and attenuated the immune response of pigs when exposed to an enteric disease challenge.

The effect of dietary protein level and amino acid supplementation on the Nile tilapia (Oreochromis niloticus) nursing performance under biofloc system conditions at cold suboptimal water temperature.

The effect of dietary protein level and amino acid supplementation on the Nile tilapia (Oreochromis niloticus) nursing performance under biofloc system conditions at cold suboptimal water temperature.

A longer adaptation period to a functional amino acid-supplemented diet improves growth performance and immune status of Salmonella Typhimurium-challenged pigs.

We recently showed that dietary supplementation with key functional amino acids (FAA) improves growth performance and immune status of Salmonella Typhimurium (ST)-challenged pigs. It is not known if ST-challenged pigs will benefit from a longer adaptation period to FAA. The objective of this study was to evaluate the effects of different adaptation periods to diets containing FAA above requirements for growth on performance and immune response of weaned pigs subsequently challenged with ST. A total of 32 mixed-sex weanling pigs (11.6 ± 0.3 kg) were randomly assigned to 1 of 4 dietary treatments, being a basal amino acid (AA) profile fed throughout the experimental period (FAA-) or a functional AA profile (FAA+; Thr, Met, and Trp at 120% of requirements) fed only in the postinoculation (FAA+0), for 1 wk pre- and postinoculation (FAA+1), or throughout the experimental period (FAA+2). After a 14-d adaptation period, pigs were inoculated with ST (2.15 × 109 CFU/mL). Growth performance, body temperature, fecal score, acute-phase proteins, oxidant/antioxidant balance, score for ST shedding in feces and intestinal colonization, and fecal and digesta myeloperoxidase (MPO) were measured pre- and postinoculation. Postinoculation body temperature and fecal score, serum haptoglobin, plasma superoxide dismutase (SOD), malondialdehyde (MDA), and fecal MPO were increased while serum albumin and plasma reduced glutathione (GSH):oxidized glutathione (GSSG) were reduced compared to pre-inoculation (P < 0.05). Average daily gain and G:F were greater in FAA+2 pigs compared to FAA- pigs (P < 0.05). Serum albumin was higher in FAA+2 and FAA+1 compared to FAA+0 and FAA- pigs (P < 0.05) while FAA+2 pigs had lower haptoglobin compared to FAA- (P < 0.05). Plasma SOD was increased and GSH:GSSG was decreased in FAA- pigs compared to the other treatments (P < 0.05). Score for ST shedding in feces was progressively lower from d 1 to 6 regardless of treatment (P < 0.05) and was lower in FAA+2 pigs compared to FAA- and FAA+0 (P < 0.05). Counts of ST in colon digesta were higher in FAA- and FAA+0 pigs compared to FAA+2 (P < 0.05). Fecal and colonic digesta MPO were lower in FAA+2 and FAA+1 pigs compared to FAA- (P < 0.05). These results demonstrate a positive effect of a longer adaptation period to FAA-supplemented diets on performance and immune status of weaned pigs challenged with Salmonella.

Invited Review: Maintain or Improve Piglet Gut Health around Weanling: The Fundamental Effects of Dietary Amino Acids.

Simple SummaryGut health has significant implications for swine production. Gut morphology and luminal microbiota play determinant roles for its health maintenance. Amino acids, a group of nutrients for pigs, are not only obligatory for maintaining gut tissue integrity, but also for supporting the growth of luminal microbiota. This review summarized the up-to-date knowledge concerning the effects of dietary amino acids on the gut health of weanling pigs. Studies have shown that different amino acids have similar but also some different effects on gut health, but how to take advantages of all these effects for field application is not clear. The interactions between the effects of non-nutrient feed additives and the fundamental effects of amino acids warrant further investigation. Considering the global push to ban the antibiotics usage for swine production, a primary effort at present may be made to explore the specific and then the concert effects of amino acids on the profile and functions of gut microbiota in young pigs.Gut health has significant implications for swine nutrient utilization and overall health. The basic gut morphology and its luminal microbiota play determinant roles for maintaining gut health and functions. Amino acids (AA), a group of essential nutrients for pigs, are not only obligatory for maintaining gut mucosal mass and integrity, but also for supporting the growth of luminal microbiota. This review summarized the up-to-date knowledge concerning the effects of dietary AA supplementation on the gut health of weanling piglets. For instance, threonine, arginine, glutamine, methionine and cysteine are beneficial to gut mucosal immunity and barrier function. Glutamine, arginine, threonine, methionine and cysteine can also assist with relieving the post-weaning stress of young piglets by improving gut immunological functions, antioxidant capacity, and/or anti-inflammatory ability. Glutamine, glutamate, glycine and cysteine can assist to reconstruct the gut structure after its damage and reverse its dysfunction. Furthermore, methionine, lysine, threonine, and glutamate play key roles in affecting bacteria growth in the lumen. Overall, the previous studies with different AA showed both similar and different effects on the gut health, but how to take advantages of all these effects for field application is not clear. It is uncertain whether these AA effects are synergetic or antagonistic. The interactions between the effects of non-nutrient feed additives and the fundamental effects of AA warrant further investigation. Considering the global push to minimize the antibiotics and ZnO usage in swine production, a primary effort at present may be made to explore the specific effects of individual AA, and then the concert effects of multiple AA, on the profile and functions of gut microbiota in young pigs.

Glycerol phenylbutyrate efficacy and safety from an open label study in pediatric patients under 2 months of age with urea cycle disorders

Background/AimsNeonatal onset Urea cycle disorders (UCDs) can be life threatening with severe hyperammonemia and poor neurological outcomes. Glycerol phenylbutyrate (GPB) is safe and effective in reducing ammonia levels in patients with UCD above 2 months of age. This study assesses safety, ammonia control and pharmacokinetics (PK) of GPB in UCD patients below 2 months of age. MethodsThis was an open-label study in UCD patients aged 0 – 2 months, consisting of an initiation/transition period (1 – 4 days) to GPB, followed by a safety extension period (6 months to 2 years). Patients presenting with a hyperammonemic crisis (HAC) did not initiate GPB until blood ammonia levels decreased to below 100 µmol/L while receiving sodium phenylacetate/sodium benzoate and/or hemodialysis. Ammonia levels, PK analytes and safety were evaluated during transition and monthly during the safety extension for 6 months and every 3 months thereafter. ResultsAll 16 patients with UCD (median age 0.48 months, range 0.1 to 2.0 months) successfully transitioned to GPB within 3 days. Average plasma ammonia level excluding HAC was 94.3 µmol/L at baseline and 50.4 µmol/L at the end of the transition period (p = 0.21). No patient had a HAC during the transition period. During the safety extension, the majority of patients had controlled ammonia levels, with mean plasma ammonia levels lower during GPB treatment than baseline. Mean glutamine levels remained within normal limits throughout the study. PK analyses indicate that UCD patients <2 months are able to hydrolyze GPB with subsequent absorption of phenylbutyric acid (PBA), metabolism to phenylacetic acid (PAA) and conjugation with glutamine. Plasma concentrations of PBA, PAA, and phenylacetylglutamine (PAGN) were stable during the safety extension phase and mean plasma phenylacetic acid: phenylacetylglutamine ratio remained below 2.5 suggesting no accumulation of GPB. All patients reported at least 1 treatment emergent adverse event with gastroesophageal reflux disease, vomiting, hyperammonemia, diaper dermatitis (37.5% each), diarrhea, upper respiratory tract infection and rash (31.3% each) being the most frequently reported. ConclusionsThis study supports safety and efficacy of GPB in UCD patients aged 0 -2 months who cannot be managed by dietary protein restriction and/or amino acid supplementation alone. GPB undergoes intestinal hydrolysis with no accumulation in this population.

Role of Dietary Amino Acids and Nutrient Sensing System in Pregnancy Associated Disorders

Defective implantation is related to pregnancy-associated disorders such as spontaneous miscarriage, intrauterine fetal growth restriction and others. Several factors proclaimed to be involved such as physiological, nutritional, environmental and managemental that leads to cause oxidative stress. Overloading of free radicals promotes oxidative stress, and the internal body system could not combat its ability to encounter the damaging effects and subsequently leading to pregnancy-related disorders. During pregnancy, essential amino acids display important role for optimum fetal growth and other necessary functions for continuing fruitful pregnancy. In this context, dietary amino acids have received much attention regarding the nutritional concerns during pregnancy. Arginine, glutamine, tryptophan and taurine play a crucial role in fetal growth, development and survival while ornithine and proline are important players for the regulation of gene expression, protein synthesis and angiogenesis. Moreover, amino acids also stimulate the mammalian target of rapamycin (mTOR) signaling pathway which plays a central role in the synthesis of proteins in placenta, uterus and fetus. This review article explores the significances of dietary amino acids in pregnancy development, regulation of nutrient-sensing pathways such as mTOR, peroxisome proliferator-activated receptors (PPARs), insulin/insulin-like growth factor signaling pathway (IIS) and 5′ adenosine monophosphate-activated protein kinase (AMPK) which exhibit important role in reproduction and its related problems. In addition, the antioxidant function of dietary amino acids against oxidative stress triggering pregnancy disorders and their possible outcomes will also be enlightened. Dietary supplementation of amino acids during pregnancy could help mitigate reproductive disorders and thereby improving fertility in animals as well as humans.

Gastrointestinal Interaction between Dietary Amino Acids and Gut Microbiota: With Special Emphasis on Host Nutrition.

The gastrointestinal tract (GIT) of humans and animals is host to a complex community of different microorganisms whose activities significantly influence host nutrition and health through enhanced metabolic capabilities, protection against pathogens, and regulation of the gastrointestinal development and immune system. New molecular technologies and concepts have revealed distinct interactions between the gut microbiota and dietary amino acids (AAs) especially in relation to AA metabolism and utilization in resident bacteria in the digestive tract, and these interactions may play significant roles in host nutrition and health as well as the efficiency of dietary AA supplementation. After the protein is digested and AAs and peptides are absorbed in the small intestine, significant levels of endogenous and exogenous nitrogenous compounds enter the large intestine through the ileocaecal junction. Once they move in the colonic lumen, these compounds are not markedly absorbed by the large intestinal mucosa, but undergo intense proteolysis by colonic microbiota leading to the release of peptides and AAs and result in the production of numerous bacterial metabolites such as ammonia, amines, short-chain fatty acids (SCFAs), branched-chain fatty acids (BCFAs), hydrogen sulfide, organic acids, and phenols. These metabolites influence various signaling pathways in epithelial cells, regulate the mucosal immune system in the host, and modulate gene expression of bacteria which results in the synthesis of enzymes associated with AA metabolism. This review aims to summarize the current literature relating to how the interactions between dietary amino acids and gut microbiota may promote host nutrition and health.

Enteropeptidase inhibition improves kidney function in a rat model of diabetic kidney disease.

AimTo examine the effects of an enteropeptidase inhibitor, SCO‐792, on kidney function in rats.Materials and MethodsThe pharmacological effects of SCO‐792 were evaluated in Wistar fatty (WF) rats, a rat model of diabetic kidney disease (DKD).ResultsOral administration of SCO‐792 increased faecal protein content and improved glycaemic control in WF rats. SCO‐792 elicited a rapid decrease in urine albumin‐to‐creatinine ratio (UACR). SCO‐792 also normalized glomerular hyperfiltration and decreased fibrosis, inflammation and tubular injury markers in the kidneys. However, pioglitazone‐induced glycaemic improvement had no effect on kidney variables. Dietary supplementation of amino acids (AAs), which bypass the action of enteropeptidase inhibition, mitigated the effect of SCO‐792 on UACR reduction, suggesting a pivotal role for enteropeptidase. Furthermore, autophagy activity in the glomerulus, which is impaired in DKD, was elevated in SCO‐792‐treated rats. Finally, a therapeutically additive effect on UACR reduction was observed with a combination of SCO‐792 with irbesartan, an angiotensin II receptor blocker.ConclusionsThis study is the first to demonstrate that enteropeptidase inhibition is effective in improving disease conditions in DKD. SCO‐792‐induced therapeutic efficacy is likely to be independent of glycaemic control and mediated by the regulation of AAs and autophagy. Taken together with a combination effect of irbesartan, SCO‐792 may be a novel therapeutic option for patients with DKD.

Effects of reduced protein level and dietary amino acid supplementation on growth, body composition and intestinal morphometry of silver catfish ( Rhamdia quelen )

The reduction in the protein level and the supplementation of lysine (Lys) and methionine (Met) in the diet were evaluated in the performance and intestinal morphometry of silver catfish (Rhamdia quelen). The study was used in a completely randomized design for 63 days, where 320 fish (26.33 ± 0.40 g) were distributed in 20 tanks (250 L, 16 fish each) and fed until the apparent satiety was reached. Five diets were formulated, a positive control [38% of crude protein (CP) (38CP)], a negative control [34% of CP (34CP)] and three test diets [34% of CP supplemented with Lys (34L), 34% of CP supplemented with Met (34M) and 34% of CP supplemented with Lys plus Met (34LM)]. Final weight and condition factor were greater in fish fed the 34LM diet than in those fed the 34CP diet (p < .05). Body lipid deposition was lower in fish fed the 34CP diet than other diets (p = .0002). In the fillet, there was a lower deposition of lipids in fish fed with 34L diet than in fish fed with 34M and 34LM diets (p <.0001). Fish fed the 34LM diet had a higher AA content in the plasma than those fed 34L and 34CP diets (p < .0001). The lower villus height was observed in fish fed the 34L diet compared to the 38CP diet (p = .021). It is possible to reduce 4% of the CP level in silver catfish diets with supplementation of Lys and Met.

Effect of Dietary Supplementation of Critical Amino Acids and Multi-Enzyme with Low Protein and Energy Diet on Carcass and Blood Biochemical Performance of Broiler Chicken

Effect of Dietary Supplementation of Critical Amino Acids and Multi-Enzyme with Low Protein and Energy Diet on Carcass and Blood Biochemical Performance of Broiler Chicken

Multiple Amino Acid Supplementations to Low-Protein Diets: Effect on Performance, Carcass Yield, Meat Quality and Nitrogen Excretion of Finishing Broilers under Hot Climate Conditions.

Simple SummaryCrude protein is an essential nutrient in poultry feed. Reducing the use of crude protein not only reduces the feed cost, but also minimizes pollution during poultry production. Thus, finding the minimum protein requirement in broiler diet without compromising broiler growth is the objective in the present study. Supplementing essential amino acids including methionine and lysine to the low-protein diet showed comparable growth performance and carcass yield to the regular protein diet. Thus, reducing the crude protein level is possible if the essential amino acid balance is adequate for broiler growth.The objective of this study was to evaluate the effect of low-protein diets with amino acid supplementation on growth performance, carcass yield, meat quality and nitrogen excretion of broilers raised under hot climate conditions during the finisher period. In trial 1, broilers from 28 to 49 days of age were fed 18% crude protein (CP) as a positive control or 15% CP supplemented with (1) DL-methionine (Met) + L-lysine (Lys), (2) Met + Lys + L-Arginine (Arg), or (3) Met + Lys + L-Valine (Val). In trial 2, broilers from 30 to 45 days of age, were fed an 18% CP diet as a positive control or 15% CP supplemented with Met, Lys, Arg, Val, L-Isoleucine (Ile) or combination with glycine (Gly) and/or urea as nitrogen sources: (1) Met + Lys, (2) Met + Lys + Arg, (3) Met + Lys + Val, (4) Met + Lys + Ile, (5) Met + Lys + Arg +Val + Ile + Gly, and (6) Met+ Lys + Arg + Val + Ile + Gly + urea. Protein use was improved by feeding low-protein amino acid-supplemented diets as compared to the high-protein diet. Feeding 15% crude protein diet supplemented with only methionine and lysine had no negative effects on carcass yield, CP, total lipids and moisture% of breast meat while decreasing nitrogen excretion by 21%.

Dietary protein levels and amino acid supplementation patterns alter the composition and functions of colonic microbiota in pigs.

Different dietary nitrogen (N) patterns may have different effects on gut microbiota. To investigate the effects of different crude protein (CP) levels or essential amino acids (EAA) supplementation patterns on the structure and functions of colonic microbiota, 42 barrows (25 ± 0.39 kg) were randomly assigned to 7 dietary treatments including: diet 1, a high CP diet with balanced 10 EAA; diet 2, a medium CP diet with approximately 2% decreased CP level from diet 1 and balanced 10 EAA; diets 3, 4, 5, 6 and 7, low CP diets with 4% decreased CP level from diet 1. Specifically, diet 3 was only balanced for Lys, Met, Thr and Trp; diets 4, 5 and 6 were further supplemented with Ile, Val and Ile + Val on the basis of diet 3, respectively; and diet 7 was balanced for 10 EAA. Results over a 110-d trial showed that reducing the CP level by 2% or 4% dramatically decreased N intake and excretion (P < 0.05) in the presence of balanced 10 EAA, which was not observed when altering the EAA supplementation patterns in low CP diet (−4%). With balanced 10 EAA, 2% reduction in dietary CP significantly reduced Firmicutes-to-Bacteroidetes (F:B) ratio and significantly elevated the abundance of Prevotellaceae NK3B31 (P < 0.05); whereas 4% reduction evidently increased the abundances of Proteobacteria, Succinivibrio and Lachnospiraceae XPB1014 (P < 0.05). Among the 5 low CP diets (−4%), supplementation with Ile, or Val + Ile, or balanced 10 EAA increased F:B ratio and the abundance of Proteobacteria. In addition, the predicted functions revealed that different CP levels and EAA balanced patterns dramatically altered the mRNA expression profiles of N-metabolizing genes, the “N and energy metabolism” pathways or the metabolism of some small substances, such as amino acids (AA) and vitamins. Our findings suggested that reducing the dietary CP levels by 2% to 4% with balancing 10 EAA, or only further supplementation with Ile or Val + Ile to a low protein diet (−4%) reduced the N contents entering the hindgut to various degrees, altered the abundances of N-metabolizing bacteria, and improved the abilities of N utilization.

Drosophila TRIM32 cooperates with glycolytic enzymes to promote cell growth

Cell growth and/or proliferation may require the reprogramming of metabolic pathways, whereby a switch from oxidative to glycolytic metabolism diverts glycolytic intermediates towards anabolic pathways. Herein, we identify a novel role for TRIM32 in the maintenance of glycolytic flux mediated by biochemical interactions with the glycolytic enzymes Aldolase and Phosphoglycerate mutase. Loss of Drosophila TRIM32, encoded by thin (tn), shows reduced levels of glycolytic intermediates and amino acids. This altered metabolic profile correlates with a reduction in the size of glycolytic larval muscle and brain tissue. Consistent with a role for metabolic intermediates in glycolysis-driven biomass production, dietary amino acid supplementation in tn mutants improves muscle mass. Remarkably, TRIM32 is also required for ectopic growth - loss of TRIM32 in a wing disc-associated tumor model reduces glycolytic metabolism and restricts growth. Overall, our results reveal a novel role for TRIM32 for controlling glycolysis in the context of both normal development and tumor growth.

Dietary Amino Acid Supplementation and its Relationship with Placental and Fetal Growth in Pigs

Fil: Romanelli, Agustina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Tandil. Centro de Investigacion Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigacion Veterinaria de Tandil. Provincia de Buenos Aires. Gobernacion. Comision de Investigaciones Cientificas. Centro de Investigacion Veterinaria de Tandil; Argentina

Low sanitary conditions increase energy expenditure for maintenance and decrease incremental protein efficiency in growing pigs

Requirements for energy and particular amino acids (AAs) are known to be influenced by the extent of immune system stimulation. Most studies on this topic use models for immune system stimulation mimicking clinical conditions. Extrapolation to conditions of chronic, low-grade immune system stimulation is difficult. We aimed to quantify differences in maintenance energy requirements and efficiency of energy and protein used for growth (incremental energy and protein efficiency) of pigs kept under low (LSC) or high sanitary conditions (HSC) that were fed either a basal diet or a diet with supplemented AA. Twenty-four groups of six 10-week-old female pigs were kept under either LSC or HSC conditions for 2 weeks and fed a diet supplemented or not with 20% extra methionine, threonine and tryptophan. In week 1, feed was available ad libitum. In week 2, feed supply was restricted to 70% of the realized feed intake (kJ/(kg BW)0.6 per day) in week 1. After week 2, fasting heat production (FHP) was measured. Energy balances and incremental energy and protein efficiencies were measured and analyzed using a GLM. Low sanitary condition increased FHP of pigs by 55 kJ/(kg BW)0.6 per day, regardless of diet. Low sanitary condition did not alter the response of faecal energy output to incremental gross energy (GE) intake, but it reduced the incremental response of metabolizable energy intake (12% units), heat production (6% units) and energy retained as protein (6% units) to GE intake, leaving energy retained as fat unaltered. Incremental protein efficiency was reduced in LSC pigs by 20% units. Incremental efficiencies for energy and protein were not affected by dietary AA supplementation. Chronic, low-grade immune stimulation by LSC treatment increases FHP in pigs. Under such conditions, the incremental efficiency of nitrogen utilization for body protein deposition is reduced, but the incremental efficiency of absorbed energy for energy or fat deposition is unaffected.

Epithelial Dysfunction in Lung Diseases: Effects of Amino Acids and Potential Mechanisms.

Lung diseases affect millions of individuals all over the world. Various environmental factors, such as toxins, chemical pollutants, detergents, viruses, bacteria, microbial dysbiosis, and allergens, contribute to the development of respiratory disorders. Exposure to these factors activates stress responses in host cells and disrupt lung homeostasis, therefore leading to dysfunctional epithelial barriers. Despite significant advances in therapeutic treatments for lung diseases in the last two decades, novel interventional targets are imperative, considering the side effects and limited efficacy in patients treated with currently available drugs. Nutrients, such as amino acids (e.g., arginine, glutamine, glycine, proline, taurine, and tryptophan), peptides, and bioactive molecules, have attracted more and more attention due to their abilities to reduce oxidative stress, inhibit apoptosis, and regulate immune responses, thereby improving epithelial barriers. In this review, we summarize recent advances in amino acid metabolism in the lungs, as well as multifaceted functions of amino acids in attenuating inflammatory lung diseases based on data from studies with both human patients and animal models. The underlying mechanisms for the effects of physiologicalamino acidsare likely complex and involve cell signaling, gene expression, and anti-oxidative reactions. The beneficial effects of amino acids are expected to improve the respiratory health and well-being of humans and other animals.Because viruses (e.g., coronavirus) and environmental pollutants (e.g., PM2.5 particles) induce severe damage to the lungs, it is important to determine whether dietary supplementation or intravenous administration of individual functional amino acids (e.g., arginine-HCl, citrulline, N-acetylcysteine, glutamine, glycine, proline and tryptophan) or their combinations to affected subjectsmay alleviate injury and dysfunction in this vital organ.

Life-extending dietary restriction, but not dietary supplementation of branched-chain amino acids, can increase organismal oxidation rates of individual branched-chain amino acids by grasshoppers.

BACKGROUND:Life-extending dietary restriction increases energy demands. Branched-chain amino acids (BCAAs), at high levels, may be detrimental to healthspan by activating the mechanistic Target of Rapamycin (mTOR). Whether organismal oxidation of BCAAs increases upon dietary restriction is unknown.OBJECTIVE:Test whether dietary restriction (DR, which creates an energy deficit) or supplemental dietary BCAAs (superfluous BCAAs) increases oxidation of BCAAs, potentially reducing their levels to improve healthspan.METHODS:Grasshoppers were reared to middle-age on one of four diets, each a level of lettuce feeding and a force-fed solution: 1) ad libitum lettuce & buffer, 2) ad libitum lettuce & supplemental BCAAs, 3) DR lettuce & buffer, and 4) DR lettuce & supplemental BCAAs. On trial days, grasshoppers were force-fed one 13C-1-BCAA (isoleucine, leucine, or valine). Breath was collected and tested for 13CO2, which represents organismal oxidation of the amino acid. Additional trials re-tested oxidation of leucine (the most potent activator of mTOR) in both females and males on dietary restriction.RESULTS:Dietary restriction generally increased cumulative oxidation of each BCAA in females and hungry males over ∼8 hr. Results were consistent for isoleucine and valine, but less so for leucine. Supplementation of BCAAs, in combination with dietary restriction, increased isoleucine in hemolymph, with similar trends for leucine and valine. Despite this, supplementation of BCAAs did not alter oxidation of any BCAAs.CONCLUSIONS:Dietary restriction can increase oxidation of BCAAs, likely due to an energy deficit. The increased oxidation may decrease available BCAAs for activation of mTOR and improve healthspan.

Fecal characteristics and gut bacterial population of weaned pigs fed amino acid-supplemented diets varying in crude protein and fermentable carbohydrate contents

A 28-day study was conducted to evaluate the effects of dietary crude protein (CP; high- and low-CP diets) and dried citrus pulp (DCP; 0 and 7.5%) contents on fecal consistency score and intestinal bacterial enumeration. A total of 108 early-weaned piglets (21 days of age; 5.82 ± 0.16 kg initial body weight) were assigned to 1 of 4 dietary treatments in a 2 × 2 factorial arrangement, with 9 replicate pens per treatment and 3 pigs per pen. The high-CP diets consisted of feeding 20 and 21% CP contents throughout phase 1 (1 to 14 day) and phase 2 (15 to 28 day), respectively. For the low-CP diets, CP contents were reduced by 4 percentage units as compared with the high-CP diets in both phases. Crystalline amino acids (AA) were supplemented to maintain an ideal AA pattern. Feces were scored for consistency during the first 7 days postweaning. Digesta samples from the ileum, cecum, and colon were collected on days 7 and 28 postweaning to determine total coliform and lactobacilli counts. There were no CP x DCP interactions for fecal consistency scores. Although fecal consistency scores were unaffected by the dietary CP contents, adding 7.5% DCP to the diet reduced (P ≤ 0.03; days 1 and 3) and tended to reduce (P ≤ 0.09; days 2 and 5) the incidence of soft feces. On day 7 postweaning, reducing dietary CP inclusion resulted in decreased (P < 0.05) ileal and colonic coliform population in pigs fed diets containing DCP. Additionally, adding 7.5% DCP to the diet decreased (P < 0.05) cecal coliform counts only for pigs fed the low-CP diet on day 7. On day 28 postweaning, there were no treatment effects on coliform population in the ileum, cecum, and colon. Ileal, cecal, and colonic counts of lactobacilli were similar among treatments on days 7 and 28 postweaning. An effect of sampling day was found for ileal coliform (P < 0.01) and cecal lactobacilli (P = 0.04) counts, with greater bacterial populations observed on day 7 when compared with day 28 postweaning. In summary, adding 7.5% DCP to low-CP AA-supplemented diets decreased coliform bacteria proliferation in piglet hindgut immediately after weaning.