Effects Of Dietary Tryptophan Supplementation Research Articles

Effects of dietary tryptophan supplementation on rectal temperature, humoral immunity, and cecal microflora composition of heat-stressed broilers.

This trial aimed to determine the effects of tryptophan (Trp) on the rectal temperature, hormone, humoral immunity, and cecal microflora composition in broiler chickens under heat stress (HS). One hundred and eighty 18 days-old female Arbor Acres broilers were randomly divided into three treatment groups, with six replicates of ten birds in each replicate. The broilers were either raised under thermoneutral conditions (TN, 23 ± 1°C) or subjected to heat stress (34 ± 1°C for 8 h daily). The TN group received a basal diet, and another two heat-stressed groups were fed the basal diet (HS) or the basal diet supplemented with 0.18% Trp (HS + 0.18% Trp) for 21 consecutive days. The basal diet contained 0.18% Trp. Results revealed that HS increased the rectal temperature, serum epinephrine (EPI), and corticotropin-releasing hormone (CRH) concentrations (p < 0.05), reduced the bursal index, the levels of serum immunoglobulin A (IgA), IgG, IgM, and serotonin (5-HT) as well as the relative abundance of Actinobacteria in cecum (p < 0.05) compared with the TN group. Dietary supplementation of Trp decreased the rectal temperature, serum dopamine (DA), EPI, and the levels of CRH and L-kynurenine (p < 0.05), increased the bursal index, the levels of serum IgA, IgM, and 5-HT as well as the relative abundance of Ruminococcus torques group in cecum of heat-stressed broilers (p < 0.05) compared to HS group. In conclusion, dietary Trp supplementation decreased rectal temperature, improved cecal microbiota community and Trp metabolism, and enhanced humoral immunity of heat-stressed broilers.

Effect of dietary tryptophan supplementation on growth, body composition and digestive enzymes activity of juvenile silver pompano Trachinotus blochii (Lacepede, 1801)

A 60-day feeding trial was conducted to study the effect of dietary supplementation of tryptophan in juvenile silver pompanoTrachinotus blochii (Lacepede, 1801) (Average initial weight=6.81±0.05 g). Five isonitrogenous and isolipidic feedssupplemented with tryptophan at different levels, 0 (TRP0), 0.5 (TRP0.5), 1.0 (TRP1.0), 1.5 (TRP1.5) and 2.0 (TRP2.0) g 100 g-1of diets were formulated. The weight gain%, specific growth rate, hepato-somatic index, digestives enzymes of stomach andintestine except protease activity in stomach, red blood cells, white blood cells, crude protein, fat and ash content of the fishwere significantly influenced (p&lt;0.05) by tryptophan supplementation. The viscero-somatic index, intraperitoneal fat ratio,muscle ratio, protease activity in the stomach and acid insoluble ash were unaffected by the treatment. Best observations interms of growth, body composition and digestive enzyme activity among the treatments were obtained in the fish group fedwith tryptophan at a level of 0.5 g 100 g-1 feed. From the current observations it can be concluded that supplementation oftryptophan at the rate of 0.5 g 100 g-1 diet can positively influence the growth of T. blochii. Keywords: Essential amino acids, Growth, Silver pompano, Tryptophan

Effects of dietary tryptophan supplementation on body temperature, hormone, and cytokine levels in broilers exposed to acute heat stress

The present study was conducted to investigate the effects of tryptophan (Trp) supplementation on rectal temperature, hormone, and cytokine levels in broilers subjected to acute heat stress. A total of 300 18-day-old female Arbor Acres broilers were randomly allocated to five dietary treatment groups with six replicates per treatment group and ten birds per replicate. Broilers were fed a basal diet and in the thermoneutral conditions (TN, 23 ± 1 °C) was considered as the TN group. Broilers were fed a basal diet and exposed to acute heat stress (HS, 34 ± 1 °C) was regarded as the HS group, and other broilers exposed to acute heat stress (34 ± 1°C) were fed a basal diet supplemented with 0.09%, 0.18%, and 0.27% Trp. Results indicated that acute heat stress increased the rectal temperature (P < 0.05), enhanced the concentrations of corticosterone (CORT), dopamine (DA), adrenaline (Adr), adrenocorticotropic hormone (ACTH), and corticotropin-releasing hormone (CRH) in serum (P < 0.05), and elevated the levels of serum tryptophan hydroxylase (TPH)1, tryptophan 2, 3-dioxygenase (TDO), indoleamine 2, 3-dioxygenase (IDO), and kynurenic acid (P < 0.05), compared with the TN group. Meanwhile, acute heat stress increased the levels of serum Trp, hypothalamic Trp, 5-hydroxytryptophan (5-HT), and interleukin-22 (P < 0.05) relative to the TN group. However, compared with the heat stress group, Trp supplementation decreased the rectal temperature of heat-stressed broilers and dietary 0.09% Trp supplementation decreased the levels of serum CRH and TDO (P < 0.05), increased the levels of serum Trp and IL-22 (P < 0.05) in heat-stressed broilers. In addition, dietary supplemented with 0.18% Trp reduced the levels of serum DA, Adr, noradrenaline (NA), CRH, TDO, IDO, kynurenic acid, IL-1β, and hypothalamic 5-HIAA/5-HT (P < 0.05), increased the levels of serum Trp, 5-HT, and IL-22, and upregulated the concentrations of hypothalamic Trp and 5-HT in heat-stressed broilers (P < 0.05). Moreover, dietary 0.27% Trp supplementation decreased the levels of serum DA, CRH, TDO, and hypothalamic 5-HIAA/5-HT (P < 0.05), and upregulated the levels of serum Trp, 5-HT, IL-22, hypothalamic Trp and 5-HT in heat-stressed broilers (P < 0.05). Taken together, dietary 0.18% Trp supplementation may be the optimal level for broilers reared under acute heat stress.

Tryptophan Alleviates Acute Heat Stress-Induced Impairment of Antioxidant Status and Mitochondrial Function in Broilers.

Heat stress has been considered as a critical risk factor for decreasing performance and causing oxidative stress in broilers. The tryptophan (TRP) derivative 5-hydroxytryptophan has been reported to protect membrane fluidity in broilers suffering from oxidative stress. Therefore, this experiment was conducted to investigate the effects of dietary TRP supplementation on antioxidant status and mitochondrial function-related genes expressions in broilers exposed to acute heat stress (34 ± 1°C, 24 h). Female Arbor Acres broilers (19-d-old, n = 180) were randomly assigned to 1 of 3 treatments. Broilers were fed a basal diet and in the thermoneutral conditions (TN, 23 ± 1°C) was considered as the TN group. Broilers were fed a basal diet and exposed to acute heat stress (HS, 34 ± 1°C) was regarded as the HS group. Broilers were fed a basal diet supplemented with 0.18% L-tryptophan and under HS conditions was treated as the HS + TRP groups. Heat stress led to increased malondialdehyde (MDA) concentration (P < 0.05), while it elevated catalase (CAT), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and total antioxidant capacity activities (T-AOC) (P < 0.05) compared with the TN group. Nevertheless, compared with the HS group, TRP supplementation increased SOD activity (P < 0.05). The effects of acute heat stress were associated with increased mRNA abundance for redox-related genes (P < 0.05), and reduced mRNA levels for mitochondrial function-related genes (P < 0.05). Notably, the effects of acute heat stress on mitochondrial function-related genes expressions were reversed by TRP treatment. Collectively, dietary 0.18% TRP supplementation beneficially protects against acute heat stress-induced oxidation stress and mitochondrial dysfunction by regulating antioxidant states and increasing mitochondrial function-related genes expressions in broilers.

PSIV-7 Effect of dietary tryptophan supplementation on growth, energy balance and blood metabolites in milk-fed low birth weight pigs

Abstract Low birth weight (LBW) is associated with reduced postnatal growth efficiency, glucose intolerance and type II diabetes mellitus in adulthood. Using a piglet model of LBW, the objective of this study was to investigate the effect of supplemental Trp on growth, energy balance and blood metabolites in LBW pigs. LBW (&amp;lt; 1.0 Kg) and normal birth weight (NBW; &amp;gt; 1.0 Kg) pigs were selected from twelve sows (parity=2–4, litter size=14–18; three LBW and one NBW piglets/sow) and randomly assigned to 4 milk-replacer based treatments (n=7–8; 7 days old) including: 1) NBW with 0% L-Trp (NBW-T0), 2) LBW with 0% L-Trp (LBW-T0), 3) LBW with 0.4% L-Trp (LBW-T0.4), and 4) LBW with 0.8% L-Trp (LBW-T0.8) for 3 weeks. Diets were provided 4–5 times/day and the voluntary intake was measured for each feeding throughout the study. Growth parameters, heat production and body weight were recorded biweekly. After an overnight fast at week 3, pigs were allowed to consume their respective diets for 1 hour and blood samples were collected at baseline (0), 60 and 120 min after the meal test. The data were analyzed using univariate GLM with Dunnett’s post-hoc test (SPSS®). No significant differences were observed on growth parameters (i.e. body weight, heart girth, wither height and body length), growth performance (i.e. average daily gain, average daily feed intake, gain:feed, gain:protein) and heat production when LBW-T0 was compared with LBW-T0.4 and LBW-T0.8. The plasma triglycerides for pigs fed LBW T0.4 and T0.8 was lower compared to that offered LBW-T0, but total cholesterol did not differ across groups. Pigs in LBW-T0.8 group had lower blood glucose than those fed LBW-T0 at 60 min after the meal challenge. In conclusion, Trp supplementation did not affect the growth and energy balance, but reduced the blood glucose and triglycerides concentration in LBW pigs.

Effects of dietary tryptophan supplementation and stocking density on growth performance and stress responses in rainbow trout (Oncorhynchus mykiss)

The aim of the present study was to investigate the effects of dietary tryptophan (Trp) supplementation on growth performance and stress responses of rainbow trout (Oncorhynchus mykiss) at low (LD) and high (HD) stocking density. For this, three diets were formulated by supplementing 0% (control), 0.5% (T0.5), and 1% (T1) Trp corresponding to 0.77, 1.85 and 3.14 g Trp per 100 g protein. In the LD treatment, the fish were initially stocked at 15 kg/m3; whereas, in the HD treatment, the fish were initially stocked at 25 kg/m3. The fish were reared under these densities and with the aforementioned diets for 70 days. After the feeding trial, the fish were sampled to determine carcass proximate composition, and blood hematological and biochemical parameters. The results showed that T0.5 had higher growth performance compared to the other treatments under the LD condition; however, there was no significant difference among the treatments under the HD condition. The increase in the fish stocking density significantly increased FCR, but the Trp-treated treatments had significantly lower FCR compared to the control treatment. Increase in the fish stocking density significantly increased carcass moisture, but decreased the carcass protein and lipid levels. The T0.5 treatment had significantly higher carcass lipid levels compared to the other treatments at the LD condition. The T0.5 treatment had significantly lower cortisol and glucose, and higher T3 levels compared to the other treatments under the LD condition; however, there was no significant difference among the treatments under the HD condition. Blood RBC and hemoglobin values significantly increased in the fish fed with 0.5% Trp supplementation; moreover, the increase in the fish stocking density significantly increased these parameters. The T0.5 treatment had significantly higher blood hematocrit levels compared to the other treatments at the LD condition. In conclusion, dietary Trp supplementation at 0.5% level is beneficial to augment growth performance in rainbow trout, when the fish initial biomass is 15 kg/m3. The mechanism of growth promotion effects of 0.5% Trp was found to be related to stress suppression. Further studies would provide data about the potential effects of Trp on rainbow trout under higher stocking densities.

Effect of dietary tryptophan supplementation on growth performance, immune response and anti-oxidant status of broiler chickens from 7 to 21 days.

BackgroundThis study was conducted to investigate the optimum dietary level of tryptophan (Trp) supplementation at which broiler chickens have better growth with efficient immune system and anti‐oxidant status.MethodOne hundred and twenty (n = 120) 1‐day‐old broiler chicks were fed a common commercial diet from days 1 to 7. On day 7, the chicks were randomly divided in three treatment groups, that is, Trp 0.2 [national research council (NRC) recommended level of tryptophan], Trp 0.3 (tryptophan supplemented at 0.3%) and Trp 0.5 (tryptophan supplemented at 0.5%). All the experimental diets were iso‐caloric (ME; 3,000 kcal/kg) and iso‐proteic (CP; 18.5%). Weekly data on feed intake and body weight gain (BWG) were recorded to calculate feed conversion ratio (FCR). On day 19, avian tuberculin was injected to note the cellular immunity. On day 21, two birds per replicate were killed to determine carcass and visceral organ weights. Blood serum samples were collected for analysis of humoral immune response against sheep red blood cells, total oxidant and anti‐oxidants by spectrophotometric method.ResultsFeed intake, carcass and visceral organ weights remained unaffected by dietary treatments while BWG and FCR tended to improve (p < .05) in broiler chicks fed the Trp 0.3 and the Trp 0.5 diets. Total oxidant status was also improved (p < .05) in broiler chicks fed the Trp 0.5 diet. Likewise, broiler chicks fed the Trp 0.3 and the Trp 0.5 diets tended to have better (p < .05) total anti‐oxidant status, catalase, glutathione peroxidase, glutathione reductase and arylesterase (ARE). The overall antibodies response and IgG improved (p < .05) by the Trp 0.3 and Trp 0.5 diets compared to control. However, IgM level remained similar across the treatment. The cellular immunity against avian tuberculin improved at 24 hr post‐injection but its effect disappeared at 48 hr.ConclusionThe results of present study revealed that Trp above the NRC recommended level may give better growth, immune response and anti‐oxidant status in broiler chickens.

Effects of dietary tryptophan supplementation in the acetic acid-induced colitis mouse model.

Inflammatory bowel disease (IBD) is characterized by chronic inflammation of the gastrointestinal tract and is strongly associated with intestinal immunity and the microbiome. Tryptophan (Trp) is an inflammatory inhibitor and modulator of the intestinal microflora. We explored the serum profile of amino acids and the effects of diet supplementation with Trp (1.0 g kg-1) on intestinal immunity and microbiota in the acetic acid-induced colitis mouse model. We analyzed the survival rate, colonic morphological parameters, profiles of serum amino acids, microbiota in colonic contents and the relative gene abundance of intestinal proinflammatory cytokines. Although the dietary Trp supplementation failed to improve the survival rate and ameliorate the morphological parameters of colon in mice with colitis, Trp modulated the general serum amino acid profile by reducing the amino acid profiles of threonine, methionine and proline, affected intestinal immunity by inhibiting the colonic expression of interleukin-22 and changed the microbiota by reducing the abundance of Candidatus, Clostridium and Coprococcus at the genus level. In conclusion, dietary Trp supplementation in a mouse model of colitis did not ameliorate the survival rate and morphological parameters of colon but did modulate the serum amino acid profiles, intestinal immunity and microbiota. These findings enhance our understanding of the roles of Trp in the metabolism of serum amino acids, intestinal immunity and microbiota.

Dietary tryptophan supplementation and affective state in pigs

Abstract The assessment and provision of welfare in farm animals has become a major issue in animal science. A key element for providing good welfare is the enabling of positive affective states in the animals. As the serotonergic system plays a central role in regulating affective behavior, an increase in centrally available serotonin (5-HT) via dietary supplementation of its precursor, tryptophan (TRP), might be an approach to induce positive affective states. Therefore, the aim of our study was to investigate the effects of dietary TRP supplementation on brain TRP metabolism and 5-HT levels but also on affective state and behavioral reactivity in pigs. All subjects were fed a standard diet until 8 weeks of age, then feed was changed for all animals, with half the animals (control) receiving a diet with the recommended TRP content (2.5 g/kg), whereas the other half (TRP+) received a TRP-enriched diet (10.2 g/kg). In part 1 of our study, we investigated the effects of the dietary TRP supplementation on TRP metabolism in brain areas related to affective and cognitive processing. We found significantly increased concentrations of TRP and its metabolites in nearly all analyzed brain tissues. In part 2 of our study, we analyzed the effects of these alterations on the affective state as measured in a cognitive bias test, namely the spatial judgment task, but also on behavioral reactivity as measured in a combined open field/novel object test. The TRP enrichment revealed no significant behavioral changes in the open field/novel object tests. In the spatial judgment task, the TRP+ group showed more pessimistic behavior after dietary change than before. Thus, our results do not support the suggestion that TRP supplementation induces positive affective states and thus improves animal welfare in pigs.

Effects of dietary tryptophan and stocking density on the performance, meat quality, and metabolic status of broilers.

BackgroundHighly automated cage-rearing systems are becoming increasingly popular in China. However, a high stocking density can cause oxidative stress and decrease broiler performance. The tryptophan (TRP) derivative 5-hydroxytryptophan (5-HT) has been shown to preserve membrane fluidity in birds suffering from oxidative stress. Therefore, this experiment was conducted to determine the effects of dietary TRP supplementation on performance, breast meat quality and oxidative stress in broilers reared in cages with a high or low stocking density.MethodsFemale Arbor Acres broilers (25-d-old, n = 144) were randomly allocated to 1 of 4 treatments. The birds were fed a diet based on corn, soybean meal, cottonseed meal and corn gluten meal containing either 0.18 or 0.27% TRP and were housed with stocking densities of 11 or 15.4 birds/m2 in a 2 × 2 factorial experiment. Broiler performance was evaluated from d 25 to 42. Eight birds from each treatment were slaughtered on d 42 and plasma and breast muscle samples were collected to measure biochemical indices.ResultsA higher stocking density tended to be associated with reduced weight gain (P < 0.10), and significantly increased plasma glutamic-pyruvic transaminase (GPT) activity (P < 0.001). Increased dietary TRP significantly reduced the activities of lactic dehydrogenase and GPT while increasing total cholesterol in the plasma (P < 0.01), reducing drip loss of breast muscle (P < 0.10) and improving feed efficiency (P < 0.10).ConclusionsAn increase in dietary TRP, 1.5-fold higher than the standard supplementation level, can alleviate oxidative stress as well as improve welfare and feed efficiency in broilers reared in cages with a high stocking density.

Effects of Dietary Tryptophan Supplementation and Feed Restriction on Growth Performance and Carcass Characteristics of Goslings

Effects of Dietary Tryptophan Supplementation and Feed Restriction on Growth Performance and Carcass Characteristics of Goslings

Dietary l-tryptophan and tank colour effects on growth performance of rainbow trout ( Oncorhynchus mykiss) juveniles reared in a recirculating water system

The aim of the present study was to evaluate the possible anti-stressful effect of dietary tryptophan supplementation on growth of juvenile rainbow trout ( Oncorhynchus mykiss) reared in different background colour using recirculating water system. Therefore, rainbow trout (4.7 g ± 0.02) were reared for 11 weeks in black, light blue and white tanks and fed either a commercial diet (CD) or the same diet supplemented with tryptophan (2 g 100 g −1 diet). Rearing in black tanks led to reduced final weight and total length, lower food consumption, food conversion ratio and body protein, while no differences were observed between fish reared in light blue or white tanks. Feeding the fish tryptophan supplemented diet resulted in depressed growth, increased food consumption and food conversion ratio, decreased body protein and increased body lipid, reduced liver total lipids and a marked increase in hepatosomatic index (least in fish reared in white tanks). It is concluded that rearing on a black background was stressful for rainbow trout juveniles, while the dietary level of tryptophan used failed as a stress-releasing factor and probably evoked an amino acid imbalance.