Trp Supplementation Research Articles

INFLUENCE OF DITARY TRYPTOPHAN SUPPLEMENTAL ON PRODUCTIVE PERFORMANCE OF SINAI BEDOUIN LAYER HENS

This experiment was conducted in the Poultry Research Farm and the Poultry Nutrition Laboratory, Faculty of Agriculture, Minufia University, Shebin El-kom, in order to investigate the effect of dietary tryptophan (Trp) supplementation on Production performance, egg quality traits and some blood constituents of Sinai Bedouin layer hens were fed on supplementation during the period of 26 to 38 wks of age were determined. Economic efficiency and phonetic correlation between some productive parameters at the different levels of tryptophan supplementation were calculated. Results showed that final body weight and weight gain were significantly (P≤ 0.05) higher by increasing of tryptophan level. Hen–day production percentage, egg number, egg weight and egg mass were significantly improved as the level of dietary tryptophan increased. Feed conversion ratio was significantly (P ≤ 0.05) improved. Pronounced effects on egg shell percentage and thickness were significantly noted. Albumen, yolk and Haugh units were improved by adding tryptophan at the level of 0.23% of laying diets. Other traits of egg quality were not significantly affected by higher tryptophan levels. High positive phenotypic correlations between some productive parameters and final body weight was noticed by increasing tryptophan levels. Significant phenotypic correlation between egg weights and some egg quality traits by increasing tryptophan levels was recorded. There was a significant increase in plasma total protein, globulin concentration resulted from dietary tryptophan. No significant differences were determined in transaminase enzymes (ALT and AST) plasma blood concentration between all treatments significantly reduced the levels of total cholesterol and triglycerides concentrations. Finally, it could be concluded that dietary tryptophan might have positive effects on productive performance, economic efficiency and health status of layer hens. In respect of Sinai Bedouin laying hens diets 0.23% tryptophan could be recommended for improve most of economic traits.

Dietary L-Tryptophan potentiates non-specific immunity in Labeo rohita fingerlings reared under elevated temperature

At present environmental scenario global climate change is a reality and its affect all living organism including fish. The aquatic ecosystem is the most affected system as it is the biggest sink for global warming and elevated temperature and obviously affects all the aquatic life forms. With this hypothesis an experiment was conducted to evaluate the effect of elevated temperature on Labeo rohita fingerlings and potential of dietary L-tryptophan (TRP) in mitigating the effects elevated temperature and enhancing the non-specific immunity. Seven hundred and twenty fishes were randomly distributed in three different thermal groups each with three replicates. The thermal groups were ambient temperature (26 °C), 34 and 38 °C. Then each thermal groups were fed with four different formulated diets containing 0. 0.36%, 0.72% and 1.44% TRP. The effect of dietary TRP supplementation was studied on stress responses, such as cortisol, blood glucose, histopathological changes in liver and kidney and immuno-hematological changes such as red blood cell count (RBC), haemoglobin (Hb), white blood cell count (WBC), lysozyme, nitroblue tetrazolium (NBT), total serum protein, albumin, globulin and albumin-globulin ratio. Subsequently the treated fish were subjected to challenge test with Aeromonas hydrophila. In the present study, primary stress markers were noticeably (p < 0.01) elevated with temperature stress and levels were reduced with nutritional supplementation of TRP. Similarly, immuno-hematological parameters were altered with the exposure of temeparture stress and got improved with dietary TRP supplementation. Results of the present study suggest that dietary supplementation of 1.44% tryptophan has definitive role in the mitigation of temperature stress and gives protection against bacterial infection to L. rohita.

Impact of the Gut Microbiota on Intestinal Immunity Mediated by Tryptophan Metabolism.

The gut microbiota influences the health of the host, especially with regard to gut immune homeostasis and the intestinal immune response. In addition to serving as a nutrient enhancer, L-tryptophan (Trp) plays crucial roles in the balance between intestinal immune tolerance and gut microbiota maintenance. Recent discoveries have underscored that changes in the microbiota modulate the host immune system by modulating Trp metabolism. Moreover, Trp, endogenous Trp metabolites (kynurenines, serotonin, and melatonin), and bacterial Trp metabolites (indole, indolic acid, skatole, and tryptamine) have profound effects on gut microbial composition, microbial metabolism, the host's immune system, the host-microbiome interface, and host immune system–intestinal microbiota interactions. The aryl hydrocarbon receptor (AhR) mediates the regulation of intestinal immunity by Trp metabolites (as ligands of AhR), which is beneficial for immune homeostasis. Among Trp metabolites, AhR ligands consist of endogenous metabolites, including kynurenine, kynurenic acid, xanthurenic acid, and cinnabarinic acid, and bacterial metabolites, including indole, indole propionic acid, indole acetic acid, skatole, and tryptamine. Additional factors, such as aging, stress, probiotics, and diseases (spondyloarthritis, irritable bowel syndrome, inflammatory bowel disease, colorectal cancer), which are associated with variability in Trp metabolism, can influence Trp–microbiome–immune system interactions in the gut and also play roles in regulating gut immunity. This review clarifies how the gut microbiota regulates Trp metabolism and identifies the underlying molecular mechanisms of these interactions. Increased mechanistic insight into how the microbiota modulates the intestinal immune system through Trp metabolism may allow for the identification of innovative microbiota-based diagnostics, as well as appropriate nutritional supplementation of Trp to prevent or alleviate intestinal inflammation. Moreover, this review provides new insight regarding the influence of the gut microbiota on Trp metabolism. Additional comprehensive analyses of targeted Trp metabolites (including endogenous and bacterial metabolites) are essential for experimental preciseness, as the influence of the gut microbiota cannot be neglected, and may explain contradictory results in the literature.

Effects of l-tryptophan on the growth, intestinal enzyme activities and non-specific immune response of sea cucumber (Apostichopus japonicus Selenka) exposed to crowding stress

In order to reveal the effects of l-tryptophan (Trp) on the physiology and immune response of sea cucumber (Apostichopus japonicus Selenka) exposed to crowding stress, four density groups of sea cucumbers (i.e. 4, 8, 16 and 32 individuals per 40 L water, represented as L, ML, MH and H) were fed with diets containing 0, 1, 3 and 5% l-tryptophan respectively for 75 days. The results showed that the specific growth rates (SGR) of the sea cucumber fed with diet with 3% Trp (L, 2.1; ML, 1.76; MH, 1.2; H, 0.7) were significantly higher than those fed with basal diet without Trp supplementation (P < .05). Peak amylase activity occurred at H stress density at 3% dietary Trp. Trypsin activity was higher in diet 3% in ML and MH densities than the controls, which increased by 66.4% and 53.8%. However, the lipase activity first increased and then decreased from the stocking density L to H, with highest values of 3% Trp group showed the highest value than other groups. Compared to those fed with the basal diet, sea cucumber fed diets with Trp (3%) had significantly higher phagocytic activities (0.28 OD540/106 cells, H) in coelomic fluid and respiratory burst activities (0.105 OD630/106 cells, MH) (P < .05). The results suggested that Trp cannot improve superoxide dismutase (SOD) activity at L, ML and MH densities. The alkaline phosphatase activity (AKP) significantly decreased at H stress density. Under the experimental conditions, the present results confirmed that a diet supplemented with 3% Trp was able to enhance intestinal enzyme activities, non-specific immune response and higher growth performance of A. japonicus.

Erratum to "Effect of High Dietary Tryptophan on Intestinal Morphology and Tight Junction Protein of Weaned Pig".

[This corrects the article DOI: 10.1155/2016/2912418.].

Short-term supplementation of isocaloric meals with L-tryptophan affects pig growth.

L-Tryptophan (Trp) and some of its metabolites regulate the circadian rhythm in mammals. We aimed to investigate the effects of short-term supplementation of Trp in isocaloric meals on growth performance using the parameters of multiple blood biomarkers and free amino acids in growing pigs. A total of 32 Landrace×Yorkshire barrows with a mean body weight of 8.64 (±1.13) kg were randomly assigned to four groups and then fed with various concentrations of Trp diets daily. Our results showed that sequential supplementation of different concentrations of Trp in isocaloric meals decreased the feed:gain (F:G) ratio (P=0.079) and plasma urea and albumin (P=0.019), whereas the level of total protein did not. Among the essential and conditionally essential amino acids, the concentrations of histidine, isoleucine, proline, threonine, arginine, and valine in the plasma decreased (P<0.05), whereas the concentrations of Trp, glycine, serine, and methionine increased (P<0.01). In addition, concentrations of branched chain amino acids also significantly decreased (P=0.004), while the rate of conversion of Trp to branched chain amino acids increased (P<0.001). Taken together, we show that administration of a high concentration of Trp in breakfast with decreasing concentrations of Trp in lunch and dinner positively affected feed utilization and improved feed efficiency, at least in part, through the optimization of amino acid interconversions and nitrogen utilization.

Suppression of Th1 differentiation by tryptophan supplementation in vivo.

Metabolism of the essential amino acid tryptophan (trp) is a key endogenous immunosuppressive pathway restricting inflammatory responses. Tryptophan metabolites promote regulatory T cell (Treg) differentiation and suppress proinflammatory T helper cell (Th)1 and Th17 phenotypes. It has been shown that treatment with natural and synthetic tryptophan metabolites can suppress autoimmune neuroinflammation in preclinical animal models. Here, we tested if oral intake of tryptophan would increase immunosuppressive tryptophan metabolites and ameliorate autoimmune neuroinflammation as a safe approach to treat autoimmune disorders like multiple sclerosis (MS). Without oral supplementation, systemic kynurenine levels decrease during the initiation phase of experimental autoimmune encephalomyelitis (EAE), a mouse model of MS, indicating systemic activation of tryptophan metabolism. Daily oral gavage of up to 10mg/mouse/day was safe and increased serum kynurenine levels by more than 20-fold for more than 3h after the gavage. While this treatment resulted in suppression of myelin-specific Th1 responses, there was no relevant impact on clinical disease activity. These data show that oral trp supplementation at subtoxic concentrations suppresses antigen-specific Th1 responses, but suggest that the increase in trp metabolites is not sustained enough to impact neuroinflammation.

Can tryptophan supplement intake at breakfast enhance melatonin secretion at night?

BackgroundTryptophan (TRP) is an essential amino acid, and it has been suggested that TRP intake at breakfast combined with daytime bright light exposure can increase nocturnal melatonin secretion. However, the mechanisms involved are not yet clear. The aim of this study was to examine the effect of TRP supplement intake at breakfast on nocturnal melatonin secretion under different daytime light intensities in humans.MethodTwelve subjects (aged 21.3 ± 3.0 years, mean ± standard deviation) participated in a random order in experimental sessions lasting 3 days under four conditions in a laboratory setting. The four conditions were TRP*Bright, Placebo*Bright, TRP*Dim, and Placebo*Dim. A TRP capsule (1000 mg) or a placebo starch capsule (1000 mg) were taken at breakfast. In addition, during the daytime (07:00–18:00), the subjects were asked to stay under different light intensities: >5000 lx (bright) or <50 lx (dim). Saliva samples were collected for measuring the concentration of melatonin. The time courses of melatonin concentration and dim light melatonin onset (DLMO) were compared among the four conditions using repeated measurements analysis of variance (ANOVA).ResultNocturnal melatonin concentrations in the bright light condition tended to be higher than in the dim light condition (main effect of light: p = .099). Moreover, in the bright light condition, the change in DLMO between baseline and after the intervention was significantly higher than that in the dim light condition (main effect of light: p <.001). However, the ANOVA results indicated no significant effect of TRP intake on melatonin secretion.ConclusionOur findings indicated that intake of 1000 mg of TRP at breakfast on 1 day did not change nocturnal melatonin secretion, even though TRP is the precursor of melatonin. In contrast, daytime bright light exposure increased nocturnal melatonin secretion and advanced the phase of melatonin onset. Therefore, TRP supplementation, unlike exposure to daytime bright light, does not acutely affect biological rhythm and sleep in humans.Trial registrationUMIN Clinical Trial Registry: UMIN000024121

Dietary Tryptophan Enhanced the Expression of Tight Junction Protein ZO-1 in Intestine.

Dietary amino acids provide various beneficial effects for our health. The aim of the present study was to assess the effects of tryptophan (Trp) supplementation on barrier function. Ninety-six healthy finishing pigs (initial body weight 51.49 ± 1.12 kg) were randomly allocated into 2 treatment groups, control group, and 0.2% Trp group. The control group was fed the basal diet, and 0.2% Trp group was fed basal diet plus 0.2% Trp. The trial period is 60 d. Compared with control group, the mRNA abundance of claudin-3 and zonula occluden-1 (ZO-1) in the jejunum in 0.2% Trp group (P < 0.05) was increased. According to immunohistochemistry and immunoblotting test, the expression of ZO-1 in jejunum in 0.2% Trp group was also significantly increased compared with the control group (P < 0.05). These results revealed that Trp enhanced the expression of tight junction protein ZO-1 in the intestine of pig model. Trp may be potential and beneficial dietary functional factor for regulating the intestinal development and inhibiting intestinal aging.

Performance of pigs kept under different sanitary conditions affected by protein intake and amino acid supplementation.

ABSTRACTThere is growing evidence that requirements for particular AA increase when pigs are kept under low sanitary conditions. The extent to which reduction in growth performance is related to these increased requirements is unclear. To evaluate this relationship, an experiment (2 × 2 × 2 factorial arrangement) was performed with 612 male pigs (9 per pen) kept under low sanitary conditions (LSC) or high sanitary conditions (HSC) and offered ad libitum access to either a normal CP concentration diet (NP; 17, 15, and 15% CP for the starter, grower, and finisher phase, respectively) or a low CP concentration diet (LP; 20% CP reduced relative to NP for each phase), each of which containing a basal AA profile (AA-B) or a supplemented AA profile (AA-S). The supplemented diet type contained 20% more Met, Thr, and Trp relative to Lys on an apparent ileal digestible basis compared with the basal diet type. Pigs were followed for a complete fattening period and slaughtered at a targeted pen weight of 110 kg. Haptoglobin concentrations in serum (0.92 g/L for LSC and 0.78 g/L for HSC) and IgG antibody titers against keyhole limpet hemocyanin (3.53 for LSC and 3.08 for HSC) collected in the starter, grower, and finisher phases and pleuritis scores at slaughter (0.51 for LSC and 0.20 for HSC) were greater for LSC pigs compared with HSC pigs (P ≤ 0.01), illustrating that sanitary conditions affected health conditions. The ADG and G:F were greater for HSC pigs compared with LSC pigs (P ≤ 0.01). The number of white blood cells (WBC) was higher in (AA-S)–fed pigs compared with (AA-B)–fed pigs when kept at LSC but not at HSC [SS (sanitary conditions) × AA interaction, P = 0.04]. Pigs fed NP had a lower number of WBC compared with pigs fed LP (P = 0.02). The number of platelets in pigs fed AA-S diets was higher compared with pigs fed AA-B diets (P ≤ 0.01). A 20% reduction in dietary supplementation of Met, Thr, and Trp relative to Lys decreased G:F more in LSC pigs than in HSC pigs (interaction, P = 0.03), illustrating that dietary requirements for these AA differ depending on sanitary conditions. This study, performed under practical conditions, shows that AA requirements are dependent on sanitary conditions. Furthermore, supplementation of diets with particular AA may improve performance, especially under poor hygienic conditions. Dietary protein concentration as well as Met, Thr, and Trp supplementation can modify immune status, which may influence resistance to subclinical and clinical diseases.

Effects of Low-Protein Diet Supplemented with Tryptophan, Pyridoxine and Niacin on Feed Intake and Growth Performance of Weaning Piglets

This study aimed to investigate the effects of dietary tryptophan (Trp), pyridoxine and niacin supplementation on feed intake and growth performance of weaning pigs fed low-protein diet. A total of 42 day-old crossbred (Landrace×Yorkshire×Duroc) of weaned female pigs were reared under seven dietary treatments. Treatments were 1) corn-soybean meal diet, 2) pyridoxine + niacin, 3) pyridoxine, 4) niacin, 5) 0.30% synthetic Trp + pyridoxine + niacin, 6) 0.30% synthetic Trp + pyridoxine and 7) 0.30% synthetic Trp + niacin. The experimental results indicated no significant difference (p>0.05) in feed intake for pigs fed the experimental diets. However, pigs fed the synthetic Trp + pyridoxine diet tended to have better feed intake among dietary treatments, followed by synthetic Trp + niacin diet. Overall (wk 1 to 8), pigs consuming supplemental Trp diets had better weight gain and feed efficiency than without Trp supplemental pigs (p<0.01). In conclusion, supplementation of Trp in combination with pyridoxine or niacin in weaning pigs diets greatly improve growth performance than only supplementing Trp alone in low crude protein diet.

Pigs experimentally infected with an enterotoxigenic strain of Escherichia coli have improved feed efficiency and indicators of inflammation with dietary supplementation of tryptophan and methionine in the immediate post-weaning period

This experiment tested the hypothesis that pigs challenged with an enterotoxigenic strain of E. coli (ETEC) will improve performance by dietary supplementation of sulfur amino acids (SAA) and tryptophan (Trp) above the current recommended levels in the immediate post-weaning period. Male pigs (n = 96) weighing 6.2 ± 0.78 kg (mean ± s.d.) and weaned at 21 days were stratified into one of four treatments based on weaning weight (n = 24). Four diets were formulated [11.2 MJ NE/kg; 20.1% crude protein, 1.25% standardised ileal digestible (SID) lysine (Lys)] according to a 2 × 2 factorial arrangement of treatments with two levels of SID SAA : Lys ratio (0.52 vs 0.60) and two levels of SID Trp : Lys ratio (0.16 vs 0.24). Diets did not contain any antimicrobial compounds. Pigs were individually housed and were fed diets for 14 days after weaning. Pigs were infected with ETEC (3.44 × 108 CFU/mL, serotype O149 : K91 : K88) on Days 5, 6, and 7 after weaning. Pigs were bled on Days 5, 8 and 14 and subsequently analysed for plasma levels of acute-phase proteins, urea, cytokines (Days 5 and 8 only) and amino acids (Days 5 and 8 only). Increasing Trp (P = 0.036) and SAA (P = 0.028) improved feed conversion ratio, and combined supplementation of SAA and Trp further improved FCR than individual supplementation of either SAA or Trp (P = 0.092). Dietary treatments had no impact on the incidence of post-weaning diarrhoea (P &gt; 0.05). Increasing SAA increased shedding of ETEC on Days 12 and 14 after weaning (P &lt; 0.019). Increasing dietary Trp reduced the intensity of inflammation (as measured by APP Index = [(C-reactive protein × PigMAP)/apolipoprotein A1]) immediately after infection with ETEC (P &lt; 0.05), while increasing dietary SAA reduced the APP index on 24 h and 7 days after ETEC infection (P &lt; 0.05). Increasing dietary SAA reduced plasma levels of interferon-gamma regardless of dietary Trp or day of sampling (P = 0.043). Increasing dietary SAA decreased plasma urea (PU) levels on Days 5, 8 and 14 (P &lt; 0.05). These data indicate that Trp supplementation reduced the intensity of inflammation and SAA supplementation decreased the pro-inflammatory interferon-gamma response and improved protein utilisation, as measured by PU, whereas supplementation with both Trp and SAA improved feed conversion ratio.

Analysis the role of arabidopsis CKRC6/ASA1 in auxin and cytokinin biosynthesis

The crosstalk between auxin and cytokinin (CK) is important for plant growth and development, although the underlying molecular mechanisms remain unclear. Here, we describe the isolation and characterization of a mutant of Arabidopsis Cytokinin-induced Root Curling 6 (CKRC6), an allele of ANTHRANILATE SYNTHASE ALPHA SUBUNIT 1 (ASA1) that encodes the a-subunit of AS in tryptophan (Trp) biosynthesis. The ckrc6 mutant exhibits root gravitropic defects and insensitivity to both CK and the ethylene precursor 1-aminocyclopropane-1-carboxylicacid (ACC) in primary root growth. These defects can be rescued by exogenous indole-3-acetic acid (IAA) or tryptophan (Trp) supplementation. Furthermore, our results suggest that the ckrc6 mutant has decreased IAA content, differential expression patterns of auxin biosynthesis genes and CK biosynthesis isopentenyl transferase (IPT) genes in comparison to wild type. Collectively, our study shows that auxin controls CK biosynthesis based on that CK sensitivity is altered in most auxin-resistant mutants and that CKs promote auxin biosynthesis but inhibit auxin transport and response. Our results also suggest that CKRC6/ASA1 may be located at an intersection of auxin, CK and ethylene metabolism and/or signaling.

Effect of High Dietary Tryptophan on Intestinal Morphology and Tight Junction Protein of Weaned Pig

Tryptophan (Trp) plays an essential role in pig behavior and growth performances. However, little is known about Trp's effects on tight junction barrier and intestinal health in weaned pigs. In the present study, twenty-four (24) weaned pigs were randomly assigned to one of the three treatments with 8 piglets/treatments. The piglets were fed different amounts of L-tryptophan (L-Trp) as follows: 0.0%, 0.15, and 0.75%, respectively, named zero Trp (ZTS), low Trp (LTS), and high Trp (HTS), respectively. No significant differences were observed in average daily gain (ADG), average daily feed intake (ADFI), and gain: feed (G/F) ratio between the groups. After 21 days of the feeding trial, results showed that dietary Trp significantly increased (P < 0.05) crypt depth and significantly decreased (P < 0.05) villus height to crypt depth ratio (VH/CD) in the jejunum of pig fed HTS. In addition, pig fed HTS had higher (P < 0.05) serum diamine oxidase (DAO) and D-lactate. Furthermore, pig fed HTS significantly decreased mRNA expression of tight junction proteins occludin and ZO-1 but not claudin-1 in the jejunum. The number of intraepithelial lymphocytes and goblet cells were not significantly different (P > 0.05) between the groups. Collectively, these data suggest that dietary Trp supplementation at a certain level (0.75%) may negatively affect the small intestinal structure in weaned pig.

Effect of dietary l-tryptophan on cannibalism, survival and growth in pikeperch Sander lucioperca (L.) post-larvae

The effect of supplemented commercial diets with crystalline l-tryptophan (TRP—5, 10 and 20 g TRP kg−1) on cannibalism, survival and growth parameters of pikeperch post-larvae (Sander lucioperca) was evaluated. Fifteen-day-old pikeperch larvae (mean weight—6.8 mg) were reared during the next 28 days (20.5 °C, 16L:8D) in glass aquaria in a recirculating aquaculture system. The enzyme-linked immunosorbent assay showed that TRP-supplemented diets were effective in increasing the levels of serotonin (5-HT) in the body tissue of pikeperch. TRP supplementation resulted in a slight decrease in both types of cannibalism, although the reduction in cannibalism impact did not amount to more than a few percent. TRP treatment had no significant influence on the final survival of pikeperch post-larvae (ranged from 20.1 ± 12.4 to 29.0 ± 12.9 %). However, contrary to the earlier studies conducted on other fish species, no significant difference in the growth rates and feeding behavior of pikeperch between TRP-fed and control group were found. The final body weight and growth rate ranged from 0.211 ± 0.014 to 0.243 ± 0.016 and from 12.19 ± 0.38 to 12.76 ± 0.35 % day−1, respectively. To our knowledge, this is the first study reporting the effects of TRP supplementation on the cannibalism–survival–growth relations in fish in the post-larval stage.

Effects of short term supplementation of l-tryptophan and reducing large neutral amino acid along with l-tryptophan supplementation on growth and stress response in pigs

Abstract Two experiments were conducted to evaluate the effects of short term dietary supplementation of l -Trp and reducing large neutral amino acid (LNAA; valine, leucine, isoleucine, tyrosine, and phenylalanine) on growth and stress response in nursery and growing pigs. In Exp. 1, 674 crossbred pigs in 40 pens at 9-week of age were randomly allotted to 2 dietary treatments with supplementation of 0.0% and 0.8% l -Trp to a corn and soybean meal basal diet. Experimental period was composed of 5 days in a nursery and 7 days in a finisher. After 12 days feeding of experimental diets, pigs were provided a common diet for an additional 7 days. In Exp. 2, 108 crossbred barrows at 6-week of age were randomly allotted to 3 dietary treatments: (1) a corn soybean meal basal diet (4.5% LNAA) supplemented with 0.0% l -Trp; (2) a corn soybean meal basal diet (4.5% LNAA) supplemented with 0.8% l -Trp; (3) a reduced LNAA (3.8%) diet supplemented with 0.7% l -Trp, which had the same Trp:LNAA ratio as treatment 2. The experimental period lasted 16 days. In Exp. 1, during the entire period, pigs fed the diet supplemented with 0.8% l -Trp had increased ADG and gain:feed (P l -Trp supplementation. On day 6, one day after mixing, pigs fed the diet supplemented with 0.8% l -Trp had a lower (P l -Trp supplementation. In Exp. 2, during the entire period, pigs fed the diet supplemented with 0.8% l -Trp or a reduced LNAA diet supplemented with 0.7% l -Trp had increased gain:feed (P l -Trp supplementation. Weight gain and gain:feed were similar (P > 0.05) between pigs fed the diet supplemented with 0.8% l -Trp and pigs fed a reduced LNAA diet supplemented with 0.7% l -Trp. In conclusion, short term supplementation of 0.8% l -Trp improved growth performance of pigs during period of social-mixing and was associated with reduced stress hormone concentrations. Dietary supplementation of 0.8% l -Trp had similar effects on feed efficiency as a reduced LNAA diet supplemented with 0.7% l -Trp, suggesting lowering LNAA is a valid method of reducing levels of l -Trp supplementation required for mitigating stress response.

Tryptophan, threonine and isoleucine supplementation in low-protein diets for commercial laying hens

Isoleucine (Ile), threonine (Thr) and tryptophan (Trp) are most likely candidates for becoming third limiting amino acids (AA) in layer diets. This work studied the effect of supplementing Ile, Thr and Trp in low-protein diets on the productive performance, egg quality and serum parameters of Hy-Line W36 laying hens. A total of 360 30-week-old laying hens were distributed in a completely randomized design into 9 treatments with 5 replications of 8 birds each. Treatments consisted of a control diet that was based on corn and soybean meal formulated with 15.5% CP. A second diet with 13% CP was formulated to meet the requirements for all essential AA of the control diet, except for Ile, Thr and Trp. The other treatments consisted of individual and combined supplementation of the aforementioned AA in the 13% CP diet. The reduction of the dietary protein level negatively influenced (p<0.05) the productivity of the hens, impairing egg production, feed conversion (kg kg-1 and kg dz-1), and egg mass. However, these variables were restored with individual and combined supplementation of the three AA in the 13% CP diet. Individually-supplemented diets with Ile, or combined with Thr and/or Trp, resulted in hens with lower (p<0.05) serum uric acid and ammonia concentrations as compared to birds receiving diets with 15.5% (control) and 13% CP. The protein levels can be reduced (13% CP) in the diet of commercial laying hens without compromising performance, egg quality or serum parameters with individual Ile, Thr or Trp supplementation.

The aromatic amino acid tryptophan stimulates skeletal muscle IGF1/p70s6k/mTor signaling in vivo and the expression of myogenic genes in vitro

ObjectivesNutrition plays a key role in the maintenance of muscle and bone mass, and dietary protein deficiency has in particular been associated with catabolism of both muscle and bone tissue. One mechanism thought to link protein deficiency with loss of muscle mass is deficiency in specific amino acids that play a role in muscle metabolism. The aim of this study was to test the hypothesis that the essential amino acid tryptophan, and its metabolite kynurenine, might directly affect muscle metabolism in the setting of protein deficiency. MethodsAdult mice (12 mo) were fed a normal diet (18% protein), as well as diets with low protein (8%) supplemented with increasing concentrations (50, 100, and 200 uM) of kynurenine (Kyn) or with tryptophan (Trp; 1.5 mM) for 8 weeks. Myoprogenitor cells were also treated with Trp and Kyn in vitro to determine their effects on cell proliferation and expression of myogenic differentiation markers. ResultsAll mice on the low-protein diets weighed less than the group fed normal protein (18%). Lean mass measured by dual-energy X-ray absorptiometry was lowest in mice on the high Kyn diet, whereas percent lean mass was highest in mice receiving Trp supplementation and percent body fat was lowest in mice receiving Trp. Enzyme-linked immunosorbent assays showed significant increases in skeletal muscle insulin-like growth factor-1, leptin, and the myostatin antagonist follistatin with Trp supplementation. mRNA microarray and gene pathway analysis performed on muscle samples demonstrate that mTor/eif4/p70s6k pathway molecules are significantly up-regulated in muscles from mice on Kyn and Trp supplementation. In vitro, neither amino acid affected proliferation of myoprogenitors, but Trp increased the expression of the myogenic markers MyoD, myogenin, and myosin heavy chain. ConclusionThese findings suggest that dietary amino acids can directly affect molecular signaling in skeletal muscle, further indicating that dietary manipulation with specific amino acids could potentially attenuate muscle loss with dietary protein deficiency.

Tryptophan concentration is the main mediator of the capacity of adipose mesenchymal stromal cells to inhibit T-lymphocyte proliferation in vitro

Background aimsMesenchymal stromal cells (MSCs) have immunomodulatory properties that are mediated by cell-to-cell interactions and paracrine effects through soluble factors, among which tryptophan (Trp) conversion into kynurenine (Kyn) through the enzymatic activity of indoleamine 2,3-dioxygenase has been proven to be of special relevance. However, the respective role of Trp depletion and/or Kyn accumulation on the inhibition of T-cell proliferation by MSCs remains unclear. MethodsThe effect of supplementation with increasing concentrations of Trp on the capacity of MSCs to inhibit T-lymphocyte proliferation in vitro was investigated. ResultsWe report that Trp supplementation impairs the capacity of adipose mesenchymal stromal cells (ASCs) to inhibit T-cell proliferation, despite the accumulation of very high concentrations of Kyn in the medium (>200 μmol/L). Moreover, Trp supplementation after 72 h of peripheral blood mononuclear cell:ASC co-culture, once the inhibitory effect of ASCs was established, reverted ASC inhibition and restored T-cell proliferation. Addition to stimulated lymphocytes of Kyn inhibited T proliferation in 3 of 10 peripheral blood mononuclear cell donors, but at different concentrations, suggesting that sensitivity of lymphocytes to Kyn might be donor-dependent. ConclusionsOur results confirm the relevance of Trp metabolism as a key mediator of the immunomodulatory properties of ASCs and clarify the respective roles of the Trp/Kyn balance.

Effects of dietary threonine and tryptophan supplementation on growing pigs induced by porcine respiratory and reproductive syndrome vaccination

A total of 32 growing pigs were used in a 2 × 2 factorial arrangement of treatments with two different diets (conventional [CON] diet vs. threonine [Thr]- and tryptophan [Trp]-rich [TTR] diet) and two immunological challenge regimens (porcine respiratory and reproductive syndrome [PRRS] vaccine vs. phosphate buffer solution [PBS]) to study the hypothesis that dietary supplementation with Trp and Thr would benefit for growing pigs vaccinated with PRRS vaccine. After feeding the experimental diets for 21 d, the pigs were intramuscularly vaccinated with PRRS or PBS. Performance data were recorded over a period of 10 weeks and are presented for the pre-challenge period (3 weeks) and the challenge period (7 weeks, where on day 1, pigs were immunologically challenged). During the pre-challenge period, the growth performance was not different between dietary treatments. PRRS vaccination resulted in increased rectal temperature and decreased feed intake and growth rate (p < 0.05). In PRRS-vaccinated pigs, diet TTR enhanced the feed intake, especially during the first 2 weeks after the PRRS vaccination compared with diet CON (p < 0.05). PRRS vaccination also resulted in increased plasma concentration of urea nitrogen, essential and non-essential amino acids (p < 0.05) and porcine reproductive and respiratory syndrome virus specific antibodies (p < 0.05), but decreased concentration of immunoproteins including alpha-1-acylglycoprotein and immunoglobulin G (p < 0.05). The alleviation of the PRRS vaccination induced decrease in feed intake and growth rate by Thr and Trp supplementation, indicating that the PRRS-vaccinated pigs had a higher Thr and Trp requirement than non-vaccinated pigs.