Plasma Essential Amino Acids Research Articles

Plasma essential amino acid levels in first episode psychosis at baseline and after antipsychotic treatment

This study assessed plasma levels of essential amino acids (EAA) in drug-naïve first episode psychosis (FEP) patients at diagnosis and after 10 weeks of antipsychotic treatment. Forty FEP patients were enrolled at baseline, with blood samples collected before and after a 10-week antipsychotic treatment period. Plasma EAA levels were measured using an LC/MS/MS method. Psychotic symptoms were evaluated using standardized inventories before and after treatment. A decrease in BPRS score of more than 40% was used to indicate treatment response. Thirty-five healthy volunteers served as the control group. Baseline plasma levels of Thr, Met, Leu, Lys, His, and Tyr were higher in FEP patients than in healthy controls. After 10 weeks of treatment, Leu, His, and Tyr increased further, primarily in treatment-responsive patients. Conversely, Val level was lower than controls in patients at baseline and remained unchanged after treatment. Increased EAA levels were correlated with lower (less severe) scores in positive symptom scales. Treatment non-responders had persistently low Tyr/large neutral amino acid (LNAA) ratio. Tyr/LNAA ratio increased after treatment, specifically in treatment-responders. Phe/Tyr ratio decreased post-treatment in both responder and non-responder groups. Elevated EAA levels in FEP patients may signify compensatory responses to increased physiological demand for neurotransmitters or energy. Combining specific EAA supplementation with antipsychotic treatment may enhance treatment response in these patients.

Postprandial plasma aminoacidemia and indices of appetite regulation following pea-rice blend, pea isolate and whey protein ingestion in healthy young adults.

Plant-derived proteins are often deficient in essential amino acids and have lower rates of digestibility than animal-derived proteins. Blending different plant-derived proteins could compensate for these deficiencies and may augment postprandial aminoacidemia over single-source plant proteins. This study assessed plasma amino acids and appetite hormones, appetite sensations and ad libitum energy intake following ingestion of a pea-rice protein blend (BLEND), compared with pea-only (PEA) and whey (WHEY) protein. In a randomised, double-blind, crossover design, ten healthy adults (M n 4, F n 6; mean (sd) age 22 (sd 3) years; BMI 24 (sd 3) kg·m2) ingested 0·3 g·kg·body mass-1 of BLEND, PEA or WHEY. Arterialised venous blood samples and appetite ratings were obtained in the fasted state and over 240 min postprandially. Energy intake was measured via an ad libitum buffet-style test meal. Mean plasma essential amino acid incremental AUC was higher in WHEY, compared with PEA (P < 0·01; mean diff (95 % CI): 44218 (15806, 72631) μmol·240 min·l-1) and BLEND (P < 0·01; 14358 (16031, 101121) μmol·240 min·l-1), with no differences between PEA and BLEND (P = 0·67). Plasma ghrelin and glucagon-like peptide-1, appetite ratings and ad libitum energy intake responses did not differ between treatments (P > 0·05 for all). Ingestion of a pea-rice protein blend did not augment postprandial aminoacidemia above pea protein, perhaps attributable to marginal differences in essential amino acid composition. No between-treatment differences in appetite or energy intake responses were apparent, suggesting that the influence of protein ingestion on perceived appetite ratings and orexigenic hormonal responses may not be solely determined by postprandial plasma aminoacidemia.

The anabolic response to a ground beef patty and soy-based meat alternative: a randomized controlled trial

BackgroundSoy-based meat alternatives (SBMA) are becoming increasingly popular, but it is unclear if they have the same anabolic effect on skeletal muscle as animal meat. ObjectivesWe aimed to compare the stimulation of skeletal muscle protein synthesis by consumption of 1 or two 4 oz patties of SBMA with 4 oz (80% protein/20% fat) beef. MethodsThe study design was a randomized controlled trial. Participants were aged 18–40 y of age and in good general health with a body mass index (kg/m2) between 20 and 32. Stable isotope tracer methods were used (L-[ring-2H5] phenylalanine, [U-13C9-15N]- tyrosine, and L-[ring-2H4] tyrosine) to quantify the response of muscle protein fractional synthetic rate (FSR) to consumption of a single beef (4 oz), single SBMA (4 oz), or two 4 oz SBMA patties (8 oz). Whole-body rates of protein synthesis, breakdown, and net balance, as well as plasma essential amino acid concentrations, were also measured. ResultsThe increase above basal in muscle protein FSR following consumption of the 4 oz beef patty (0.020 ± 0.016%/h) was significantly greater than the increase following consumption of 4 oz SBMA (P = 0.021; 0.003 ± 0.010%/h) but not 8 oz SBMA (P = 0.454; 0.013 ± 0.016%/h). The maximal essential amino acid concentration was significantly correlated (P = 0.046; r = 0.411) with the change in muscle FSR from the basal to the postprandial period. In addition, the change in muscle FSR from the basal to postprandial period was significantly correlated (P = 0.046; r = 0.412) with the corresponding change in whole-body protein synthesis. ConclusionsConsumption of a 4 oz beef patty stimulates muscle and whole-body protein synthesis >4 oz SBMA patty and similarly to 8 oz of SBMA.This trial was registered at clinicaltrials.gov as NCT05197140.

Chemotherapy-Induced Changes in Plasma Amino Acids and Lipid Oxidation of Resected Patients with Colorectal Cancer: A Background for Future Studies.

Previous studies have documented that FOLFOX and XELOX therapies negatively impact the metabolism of skeletal muscle and extra-muscle districts. This pilot study tested whether three-month FOLFOX or XELOX therapy produced changes in plasma amino acid levels (PAAL) (an estimation of whole-body amino acid metabolism) and in plasma levels of malondialdehyde (MDA), a marker of lipid hyper oxidation. Fourteen ambulatory, resected patients with colorectal cancer scheduled to receive FOLFOX (n = 9) or XELOX (n = 5) therapy, after overnight fasting, underwent peripheral venous blood sampling, to determine PAAL and MDA before, during, and at the end of three-month therapy. Fifteen healthy matched subjects (controls) only underwent measures of PAAL at baseline. The results showed changes in 87.5% of plasma essential amino acids (EAAs) and 38.4% of non-EAAs in patients treated with FOLFOX or XELOX. These changes in EAAs occurred in two opposite directions: EAAs decreased with FOLFOX and increased or did not decrease with XELOX (interactions: from p = 0.034 to p = 0.003). Baseline plasma MDA levels in both FOLFOX and XELOX patients were above the normal range of values, and increased, albeit not significantly, during therapy. In conclusion, three-month FOLFOX or XELOX therapy affected plasma EAAs differently but not the baseline MDA levels, which were already high.

440 Muscle Protein Synthesis and Whole-Body Protein Balance Following Ingestion of Beef or a Soy Protein Based Meat Alternative

OBJECTIVES/GOALS: We endeavor to investigated the hypothesis that muscle protein synthesis (MPS) is stimulated more after consumption of a 4-ounce beef patty as compared to 4- and 8-ounces of a soy protein based meat alternative (SPBMA) and if a greater stimulation is related to differences in the responses of plasma essential amino acid (EAA) concentrations. METHODS/STUDY POPULATION: Participants were aged 18 to 40 years of age with a BMI between 20 and 32 kg/m2. Written informed consent was obtained from all participants, and approved by UAMS IRB. Participants were assigned to one of three intervention groups via a single-blinded permuted block randomization, stratified for sex: 4 oz beef patty; 4 oz SPBMA; 2 x 4 oz (8oz) SPBMA. The impossible burgerTM was selected as it is primarily soy protein, a high-quality plant protein, and specifically designed to mimic a beef burger. Stable isotope were infused to assess protein metabolism. Appropriate muscle and blood samples were obtained. Enrichment and plasma EAA concentrations were measured with mass spectrometry. ANOVA’s on the change from basal to postprandial were used to identify group difference, significance was accepted at p &lt; 0.05. RESULTS/ANTICIPATED RESULTS: The MPS increase from basal to postprandial indicated a significant main effect of group (p = 0.026), with the beef group (0.020 ± 0.016%/hour) being significantly greater than the 4oz SPBMA (0.003 ± 0.010%/hour; p = 0.021) but not the 8oz PBMA group (0.013 ± 0.016%/hour; p = 0.454). Similar results were observed for whole-body protein synthesis, where the beef group (p = 0.042) and 8oz SPBMA (p = 0.033) were significantly greater than the 4oz SPBMA (p = 0.021). Whole-body protein balance was significantly greater in the 8oz SPBMA as compared to 4oz of beef and SPBMA. Lastly, we observed a significantly relationship (p = 0.046; r = 0.411) between the maximal plasma EAA concentration and change in MPS, indicating the greater rate of MPS following 4oz of beef is mediated by an higher increase in plasma EAA concentrations. DISCUSSION/SIGNIFICANCE: In conclusion, 4oz of beef stimulates muscle protein FSR more than 4oz of a SPBMA. A common SPBMA can stimulate increase in protein metabolism, however, greater amounts are required as compared to beef protein. Further, the change in the muscle protein FSR response was significantly correlated with the maximal EAA concentration.

Plant Protein Blend Ingestion Stimulates Postexercise Myofibrillar Protein Synthesis Rates Equivalently to Whey in Resistance-Trained Adults.

Whey protein ingestion is typically considered an optimal dietary strategy to maximize myofibrillar protein synthesis (MyoPS) after resistance exercise. Although single-source plant protein ingestion is typically less effective, at least partly, due to less favorable amino acid profiles, this could theoretically be overcome by blending plant-based proteins with complementary amino acid profiles. We compared the postexercise MyoPS response after the ingestion of a novel plant-derived protein blend with an isonitrogenous bolus of whey protein. Ten healthy, resistance-trained, young adults (male/female: 8/2; age: 26 ± 6 yr; BMI: 24 ± 3 kg·m -2 ) received a primed continuous infusion of L-[ ring - 2 H 5 ]-phenylalanine and completed a bout of bilateral leg resistance exercise before ingesting 32 g protein from whey (WHEY) or a plant protein blend (BLEND; 39.5% pea, 39.5% brown rice, 21.0% canola) in a randomized, double-blind crossover fashion. Blood and muscle samples were collected at rest, and 2 and 4 h after exercise and protein ingestion, to assess plasma amino acid concentrations, and postabsorptive and postexercise MyoPS rates. Plasma essential amino acid availability over the 4 h postprandial postexercise period was ~44% higher in WHEY compared with BLEND ( P = 0.04). From equivalent postabsorptive values (WHEY, 0.042 ± 0.020%·h -1 ; BLEND, 0.043 ± 0.015%·h -1 ) MyoPS rates increased after exercise and protein ingestion (time effect; P < 0.001) over a 0- to 2-h period (WHEY, 0.085 ± 0.037%·h -1 ; BLEND, 0.080 ± 0.037%·h -1 ) and 2- to 4-h period (WHEY, 0.085 ± 0.036%·h -1 ; BLEND, 0.086 ± 0.034%·h -1 ), with no differences between conditions during either period or throughout the entire (0-4 h) postprandial period (time-condition interactions; all P > 0.05). Ingestion of a novel plant-based protein blend stimulates postexercise MyoPS to an equivalent extent as whey protein, demonstrating the utility of plant protein blends to optimize postexercise skeletal muscle reconditioning.

Effects of Individual Essential Amino Acids on Growth Rates of Young Rats Fed a Low-Protein Diet.

To investigate the effects of individual essential amino acids (EAA) on growth and the underlying mechanisms, EAA individually supplemented a low-protein (LP) diet fed to young rats in the present study. Treatments were an LP diet that contained 6% crude protein (CP), a high-protein (HP) diet that contained 18% CP, and 10 LP diets supplemented with individual EAA to achieve an EAA supply equal to that of the HP diet. The CP concentration of the LP diet was ascertained from the results of the first experiment, which examined the effects of dietary CP concentrations on growth rates, with CP ranging from 2% to 26%. Weight gain was increased with the supplementation of His, Ile, Lys, Thr, or Trp as compared to the LP diet (p < 0.05). Feed intake was greater for the His-, Lys-, and Thr-supplemented treatments as compared to the LP group (p < 0.05). Protein utilization efficiency was lower for the HP group than other groups (p < 0.01). The supplementation of Leu, Lys, and Val led to reduced protein utilization efficiency (p < 0.05), but the supplementation of Thr and Trp led to greater efficiency than the LP group (p < 0.05). Compared to the LP group, plasma urea concentrations were elevated with individual EAA supplementation, with the exception of the Thr addition. The added EAA resulted in increased concentrations of the corresponding EAA in plasma, except for Arg and Phe supplementation. The supplementation of Arg, His, Leu, Lys, and Met individually stimulated mTORC1 pathway activity (p < 0.05), and all EAA resulted in the decreased expression of ATF4 (p < 0.05). In summary, the supplementation of His, Ile, Lys, Thr, or Trp to an LP diet improved the growth performance of young rats. Responses to His and Lys additions were related to the activated mTORC1 pathway and feed intake increases. The improved growth performance resulting from the addition of a single EAA is not solely attributed to the increased plasma availability of EAA. Rather, it may be the consequence of a confluence of factors encompassing signaling pathways, the availability of amino acids, and other associated elements. The additivity of these factors results in independent responses to several EAA with no order of limitation, as is universally encoded in growth models for all production animal species.

The impact of heat treatment of bovine milk on gastric emptying and nutrient appearance in peripheral circulation in healthy females: a randomized controlled trial comparing pasteurized and ultra-high temperature milk

BackgroundHeat treatments of dairy, including pasteurization and ultra-high temperature (UHT) processing, alter milk macromolecular structures, and ultimately affect digestion. In vitro, animal, and human studies show faster nutrient release or circulating appearance after consuming UHT milk (UHT-M) compared with pasteurized milk (PAST-M), with a faster gastric emptying (GE) rate proposed as a possible mechanism. ObjectivesTo investigate the impact of milk heat treatment on GE as a mechanism of faster nutrient appearance in blood. We hypothesized that GE and circulating nutrient delivery following consumption would be faster for UHT-M than PAST-M. MethodsIn this double-blind randomized controlled cross-over trial, healthy female (n = 20; 27.3 ± 1.4 y, mean ± SD) habitual dairy consumers, consumed 500 mL of either homogenized bovine UHT-M or PAST-M (1340 compared with 1320 kJ). Gastric content volume (GCV) emptying half-time (T50) was assessed over 3 h by magnetic resonance imaging subjective digestive symptoms, plasma amino acid, lipid and B vitamin concentrations, and gastric myoelectrical activity were measured over 5 h. ResultsAlthough GCV T50 did not differ (102 ± 7 min compared with 89 ± 8 min, mean ± SEM, UHT-M and PAST-M, respectively; P = 0.051), GCV time to emptying 25% of the volume was 31% longer following UHT-M compared with PAST-M (42 ± 2 compared with 32 ± 4 min, P = 0.004). Although GCV remained larger for a longer duration following UHT-M (treatment × time interaction, P = 0.002), plasma essential amino acid AUC was greater following UHT-M than PAST-M (55,324 ± 3809 compared with 36,598 ± 5673 μmol·min·L-1, P = 0.006). Heat treatment did not impact gastric myoelectrical activity, plasma appetite hormone markers or subjective appetite scores. ConclusionsContrary to expectations, GE was slower with UHT-M, yet, as anticipated, aminoacidemia was greater. The larger GCV following UHT-M suggests that gastric volume may poorly predict circulating nutrient appearance from complex food matrices. Dairy heat treatment may be an effective tool to modify nutrient release by impacting digestion kinetics. Clinical Trial Registrywww.anzctr.org.au (ACTRN12620000172909).

Postprandial plasma amino acid and appetite responses with ingestion of a novel salmon-derived protein peptide in healthy young adults.

This study assessed postprandial plasma aminoacidemia, glycemia, insulinemia and appetite responses to ingestion of a novel salmon-derived protein peptide (Salmon PP) compared with milk protein isolate (Milk PI). In a randomised, participant-blind crossover design, eleven healthy adults (M = 5, F = 6; mean ± sd age: 22 ± 3 years; BMI: 24 ± 3 kg/m2) ingested 0·3 g/kg/body mass of Salmon PP or Milk PI. Arterialised blood samples were collected whilst fasted and over a 240-min postprandial period. Appetite sensations were measured via visual analogue scales. An ad libitum buffet-style test meal was administered after each trial. The incremental AUC (iAUC) plasma essential amino acid (EAA) response was similar between Salmon PP and Milk PI. The iAUC plasma leucine response was significantly greater following Milk PI ingestion (P < 0·001), whereas temporal and iAUC plasma total amino acid (P = 0·001), non-essential amino acid (P = 0·002), glycine (P = 0·0025) and hydroxyproline (P < 0·001) responses were greater following Salmon PP ingestion. Plasma insulin increased similarly above post-absorptive values following Salmon PP and Milk PI ingestion, whilst plasma glucose was largely unaltered. Indices of appetite were similarly altered following Salmon PP and Milk PI ingestion, and total energy and macronutrient intake during the ad libitum meal was similar between Salmon PP and Milk PI. The postprandial plasma EAA, glycine, proline and hydroxyproline response to Salmon PP ingestion suggest this novel protein source could support muscle and possibly connective tissue adaptive remodelling, which warrants further investigation, particularly as the plasma leucine response to Salmon PP ingestion was inferior to Milk PI.

Post-prandial muscle protein synthesis rates following the ingestion of pea-derived protein do not differ from ingesting an equivalent amount of milk-derived protein in healthy, young males.

Plant-derived proteins have received considerable attention as an alternative to animal-derived proteins. However, plant-derived proteins are considered to have less anabolic properties when compared with animal-derived proteins. The lower muscle protein synthesis rates following ingestion of plant- compared with animal-derived protein have been attributed to the lower essential amino acid content of plant-derived proteins and/or their specific amino acid deficiencies. This study aimed to compare post-prandial muscle protein synthesis rates following the ingestion of 30g pea-derived protein with 30g milk-derived protein in healthy, young males. In a randomized, double-blind, parallel-group design, 24 young males (24 ± 3 y) received a primed continuous L-[ring-13C6]-phenylalanine infusion after which they ingested 30g pea (PEA) or 30g milk-derived protein (MILK). Blood and muscle biopsies were collected frequently for 5h to assess post-prandial plasma amino acid profiles and subsequent post-prandial muscle protein synthesis rates. MILK increased plasma essential amino acid concentrations more than PEA over the 5h post-prandial period (incremental area under curve 151 ± 31 vs 102 ± 15mmol∙300min∙L-1, respectively; P < 0.001). Ingestion of both MILK and PEA showed a robust muscle protein synthetic response with no significant differences between treatments (0.053 ± 0.013 and 0.053 ± 0.017%∙h-1, respectively; P = 0.96). Post-prandial muscle protein synthesis rates following the ingestion of 30g pea-derived protein do not differ from the response following ingestion of an equivalent amount of milk-derived protein. International Clinical Trials Registry Platform (NTR6548; 27-06-2017).

Effect of dietary nitrogen content and ammonium phosphate inclusion on lysine requirement for nitrogen retention in growing pigs

Inclusion of a source of non-protein nitrogen (NPN) may improve essential amino acid (EAA) and nitrogen (N) utilization in N-limiting diets. Growing barrows (20.4 ± 0.5 kg) were randomly assigned to 1 of 10 dietary treatments ( n = 9 pigs/treatment) in nine blocks. Diets contained no ammonium phosphate (NAP) or 1.7% ammonium phosphate (AP) to have an EAA-N:total N ratio of 0.36 and 0.33, respectively, with graded levels of dietary lysine (Lys; 0.8%, 0.9%, 1.0%, 1.1%, and 1.2% standardized ileal digestible (SID)). Following a 7-day dietary adaptation, a 4-day N-balance collection period was conducted. Blood samples were obtained on day 2 of the collection period. Nitrogen retention (NR) increased and urinary N output decreased with inclusion of NPN and increasing Lys ( P &lt; 0.01). Plasma urea N decreased with increasing Lys ( P &lt; 0.05). Total plasma EAA content was reduced with NPN supplementation ( P &lt; 0.05), while content of Arg, Asp, Gln, and Glu was increased ( P &lt; 0.01). The linear breakpoint model indicated that NR was maximized at 1.00% SID Lys in NAP-fed pigs and at 1.09% SID Lys in AP-fed pigs. These results indicate that diets deficient in dietary N reduce NR and Lys requirement, which were in turn increased with NPN supplementation.

Effects of heating soybeans on postruminal amino acid bioavailability, performance, and ruminal fermentation in lactating cows.

Soybeans can provide ruminally degradable protein, lipid, and metabolizable amino acid (AA) to lactating dairy cows; however, soy-based trypsin inhibitors can limit protein digestion in nonruminants. Eight ruminally cannulated lactating Holstein cows were used to evaluate the impacts of soy-based trypsin inhibitors on nutrient disappearance, lactation, and plasma AA bioavailability. Treatments were abomasal infusion of 0 or 400g/d casein or a crystalline AA analog of casein with unroasted or roasted soybeans fed at 10% dry matter (DM). Data were analyzed using the MIXED procedure of SAS. Measures of digestion were determined from fecal output determined with acid detergent insoluble ash and urine output determined from measures of urine creatinine. Neither soybean processing (P ≥ 0.20) nor the source of abomasal infusion (P ≥ 0.60) impacted nutrient digestibility. Ruminal ammonia, isobutyrate, and isovalerate were increased (P ≤ 0.01) among cattle consuming unroasted soybeans. Source of infusion did not affect (P ≥ 0.38) ruminal volatile fatty acids or nitrogen metabolism. Ruminal N metabolism was largely unaffected by soybean processing although microbial N efficiency was greater (P < 0.01) among cows fed unroasted soybeans. DM intake and energy-corrected milk were greater (P < 0.01) in cows fed roasted compared to unroasted soybeans. The proportion of fat, protein, lactose, and solids not fat (SNF) in milk did not differ between soybean processing or postruminal AA source, but fat, protein, lactose, and SNF yield was greater (P ≤ 0.01) when cows were fed roasted soybeans because milk yields were greater when cows were fed roasted vs. unroasted soybeans. As expected, infusion of casein or its crystalline AA analog increased plasma essential AA and milk urea nitrogen concentration. The rate of increase in essential AA concentration in plasma was 2.9× greater for casein than for crystalline AA. These data seem to indicate that soy-based trypsin inhibitors have no impacts on postruminal AA bioavailability when fed to cows and that metabolizable protein from casein is greater than from crystalline AA.

Higher Muscle Protein Synthesis Rates Following Ingestion of an Omnivorous Meal Compared with an Isocaloric and Isonitrogenous Vegan Meal in Healthy, Older Adults

BackgroundPlant-derived proteins are considered to have fewer anabolic properties when compared with animal-derived proteins. The anabolic properties of isolated proteins do not necessarily reflect the anabolic response to the ingestion of whole foods. The presence or absence of the various components that constitute the whole-food matrix can strongly impact protein digestion and amino acid absorption and, as such, modulate postprandial muscle protein synthesis rates. So far, no study has compared the anabolic response following ingestion of an omnivorous compared with a vegan meal. ObjectivesThis study aimed to compare postprandial muscle protein synthesis rates following ingestion of a whole-food omnivorous meal providing 100 g lean ground beef with an isonitrogenous, isocaloric whole-food vegan meal in healthy, older adults. MethodsIn a randomized, counter-balanced, cross-over design, 16 older (65–85 y) adults (8 males, 8 females) underwent 2 test days. On one day, participants consumed a whole-food omnivorous meal containing beef as the primary source of protein (0.45 g protein/kg body mass; MEAT). On the other day, participants consumed an isonitrogenous and isocaloric whole-food vegan meal (PLANT). Primed continuous L-[ring-13C6]-phenylalanine infusions were applied with blood and muscle biopsies being collected frequently for 6 h to assess postprandial plasma amino acid profiles and muscle protein synthesis rates. Data are presented as means ± standard deviations and were analyzed by 2 way-repeated measures analysis of variance and paired-samples t tests. ResultsMEAT increased plasma essential amino acid concentrations more than PLANT over the 6-h postprandial period (incremental area under curve 87 ± 37 compared with 38 ± 54 mmol·6 h/L, respectively; P-interaction < 0.01). Ingestion of MEAT resulted in ∼47% higher postprandial muscle protein synthesis rates when compared with the ingestion of PLANT (0.052 ± 0.023 and 0.035 ± 0.021 %/h, respectively; paired-samples t test: P = 0.037). ConclusionsIngestion of a whole-food omnivorous meal containing beef results in greater postprandial muscle protein synthesis rates when compared with the ingestion of an isonitrogenous whole-food vegan meal in healthy, older adults.This study was registered at clinicaltrials.gov as NCT05151887.

Extrusion of lupines with or without addition of reducing sugars: Effects on the formation of Maillard reaction compounds, partition of nitrogen and Nε-carboxymethyl-lysine, and performance of dairy cows

The extrusion of leguminous seeds induces the formation of Maillard reaction compounds (MRC) as a product of protein advanced glycation and oxidation, which lowers protein degradability in the rumen. However, the quantitative relationship between the parameters of pretreatment (i.e., addition of reducing sugars) and extrusion, and the formation of MRC has not been established yet. Moreover, the fate of the main stable MRC, Nε-carboxymethyl-lysine (CML), in the excretory routes has never been investigated in ruminants. We aimed to test the effects of the temperature of extrusion of white lupines with or without addition of reducing sugars on the formation of MRC, crude protein (CP) degradability in the rumen, N use efficiency for milk production (milk N/N intake), and performance of dairy cows. Two experiments with a replicated 4 × 4 Latin square design were conducted simultaneously with 16 (3 rumen-cannulated) multiparous Holstein cows to measure indicators of ruminal CP degradability (ruminal NH3 concentration, branched-chain volatile fatty acids), metabolizable protein supply (plasma essential AA concentration), N use efficiency (N isotopic discrimination), and dairy performance. In parallel, apparent total-tract digestibility of dry matter, organic matter, neutral detergent fibers, N, total Lys and CML, and partition of N and CML were measured with 4 cows in both experiments. The diets consisted on a DM basis of 20% raw or extruded lupines and 80% basal mixed ration of corn silage, silage and hay from permanent grasslands, pelleted concentrate, and a vitaminized mineral mix. Expected output temperatures of lupine extrusion were 115°C, 135°C, and 150°C, without and with the addition of reducing sugars before extrusion. The extrusion numerically reduced the in vitro ruminal CP degradability of the lupines, and consequently increased the predicted supply of CP to the small intestine. Nitrogen balance and urinary N excretion did not differ among dietary treatments in either experiment. Milk yield and N use efficiency for milk production increased with extrusion of lupines at 150°C without addition of reducing sugars compared with raw lupines. Nitrogen isotopic discrimination between dietary and animal proteins (the difference between δ15N in plasma and δ15N in the diet) were lower with lupines extruded at 150°C without and with addition of reducing sugars. Regardless of sugar addition, milk true protein yield was not affected, but milk urea concentration and fat:protein ratio were lower with lupines extruded at 150°C than with raw lupines. In the CML partition study, we observed that on average 26% of the apparently digested CML was excreted in urine, and a much lower proportion (0.63% on average) of the apparently digested CML was secreted in milk, with no differences among dietary treatments. In conclusion, we showed that the extrusion of white lupines without or with addition of reducing sugars numerically reduced enzymatic CP degradability, with limited effects on N partition, but increased milk yield and N use efficiency at the highest temperature of extrusion without addition of reducing sugars.

Ingestion of mycoprotein, pea protein, and their blend support comparable postexercise myofibrillar protein synthesis rates in resistance-trained individuals.

Pea protein is an attractive nonanimal-derived protein source to support dietary protein requirements. However, although high in leucine, a low methionine content has been suggested to limit its anabolic potential. Mycoprotein has a complete amino acid profile which, at least in part, may explain its ability to robustly stimulate myofibrillar protein synthesis (MyoPS) rates. We hypothesized that an inferior postexercise MyoPS response would be seen following ingestion of pea protein compared with mycoprotein, which would be (partially) rescued by blending the two sources. Thirty-three healthy, young [age: 21 ± 1 yr, body mass index (BMI): 24 ± 1 kg·m-2] and resistance-trained participants received primed, continuous infusions of l-[ring-2H5]phenylalanine and completed a bout of whole body resistance exercise before ingesting 25 g of protein from mycoprotein (MYC, n = 11), pea protein (PEA, n = 11), or a blend (39% MYC, 61% PEA) of the two (BLEND, n = 11). Blood and muscle samples were taken pre-, 2 h, and 4 h postexercise/protein ingestion to assess postabsorptive and postprandial postexercise myofibrillar protein fractional synthetic rates (FSRs). Protein ingestion increased plasma essential amino acid and leucine concentrations (time effect; P < 0.0001), but more rapidly in BLEND and PEA compared with MYC (time × condition interaction; P < 0.0001). From similar postabsorptive values (MYC, 0.026 ± 0.008%·h-1; PEA, 0.028 ± 0.007%·h-1; BLEND, 0.026 ± 0.006%·h-1), resistance exercise and protein ingestion increased myofibrillar FSRs (time effect; P < 0.0001) over a 4-h postprandial period (MYC, 0.076 ± 0.004%·h-1; PEA, 0.087 ± 0.01%·h-1; BLEND, 0.085 ± 0.01%·h-1), with no differences between groups (all; P > 0.05). These data show that all three nonanimal-derived protein sources have utility in supporting postexercise muscle reconditioning.NEW & NOTEWORTHY This study provides evidence that pea protein (PEA), mycoprotein (MYC), and their blend (BLEND) can support postexercise myofibrillar protein synthesis rates following a bout of whole body resistance exercise. Furthermore, these data suggest that a methionine deficiency in pea may not limit its capacity to stimulate an acute increase in muscle protein synthesis (MPS).

Effects of Consuming Ounce-Equivalent Portions of Animal- vs. Plant-Based Protein Foods, as Defined by the Dietary Guidelines for Americans on Essential Amino Acids Bioavailability in Young and Older Adults: Two Cross-Over Randomized Controlled Trials.

The Dietary Guidelines for Americans (DGA) recommends consuming a variety of "Protein Foods" based on "ounce-equivalent" (oz-eq) portions. No study has assessed the same oz-eq portions of animal- vs. plant-based protein foods on essential amino acid (EAA) bioavailability for protein anabolism in young and older adults. We assessed the effects of consuming two oz-eq portions of pork, eggs, black beans, and almonds on postprandial EAA bioavailability in young and older adults. We conducted two investigator-blinded, randomized crossover trials in young (n = 30; mean age ± SD: 26.0 ± 4.9 y) and older adults (n = 25; mean age ± SD: 64.2 ± 6.6 y). Participants completed four testing sessions where they consumed a standardized meal with two oz-eq of either unprocessed lean pork, whole eggs, black beans, or sliced almonds. Blood samples were taken at baseline and 30, 60, 120, 180, 240, and 300 min postprandially. Plasma EAA bioavailability was based on postprandial integrated positive areas under the curve. Participant age did not affect EAA bioavailability among the four protein foods tested. Two oz-eq portions of pork (7.36 g EAA) and eggs (5.38 g EAA) resulted in greater EAA bioavailability than black beans (3.02 g EAA) and almonds (1.85 g EAA) in young and older adults, separately or combined (p < 0.0001 for all). Pork resulted in greater EAA bioavailability than eggs in young adults (p < 0.0001), older adults (p = 0.0007), and combined (p < 0.0001). There were no differences in EAA bioavailability between black beans and almonds. The same "oz-eq" portions of animal- and plant-based protein foods do not provide equivalent EAA content and postprandial bioavailability for protein anabolism in young and older adults.

Processed fava bean as a substitute for rapeseed meal with or without rumen-protected methionine supplement in grass silage-based dairy cow diets

Fava bean offers a sustainable home-grown protein source for dairy cows, but fava bean protein is extensively degraded in the rumen and has low Met concentration. We studied the effects of protein supplementation and source on milk production, rumen fermentation, N use, and mammary AA utilization. The treatments were unsupplemented control diet, and isonitrogenously given rapeseed meal (RSM), processed (dehulled, flaked, and heated) fava bean without (TFB) or with rumen-protected (RP) Met (TFB+). All diets consisted of 50% grass silage and 50% cereal-based concentrate including studied protein supplement. The control diet had 15% of crude protein and protein-supplemented diets 18%. Rumen-protected Met in TFB+ corresponded to 15 g/d of Met absorbed in the small intestine. Experimental design was a replicated 4 × 4 Latin square with 3-wk periods. The experiment was conducted using 12 multiparous mid-lactation Nordic Red cows, of which 4 were rumen cannulated. Protein supplementation increased dry matter intake (DMI), and milk (31.9 vs. 30.7 kg/d) and milk component yields. Substituting RSM with TFB or TFB+ decreased DMI and AA intake but increased starch intake. There were no differences in milk yield or composition between RSM diet and TFB diets. Rumen-protected Met did not affect DMI, or milk or milk component yields but increased milk protein concentration in comparison to TFB. There were no differences in rumen fermentation except for increased ammonium-N concentration with the protein-supplemented diets. Nitrogen-use efficiency for milk production was lower for the supplemented diets versus control diet but tended to be greater for TFB and TFB+ versus RSM. Protein supplementation increased plasma essential AA concentration but there were no differences between TFB diets and RSM. Rumen-protected Met clearly increased plasma Met concentration (30.8 vs. 18.2 µmol/L) but did not affect other AA. Absence of differences between RSM and TFB in milk production together with limited effects of RP Met suggest that TFB is a potential alternative protein source for dairy cattle.

Combined enteral infusion of glutamine, carbohydrates, and antioxidants modulates gut protein metabolism in humans

Background:Available data suggest that nutrients can affect intestinal protein metabolism, which contributes to the regulation of gut barrier function. Objective:We aimed to assess whether an oral nutritional supplement (ONS) containing glutamine (as the dipeptide Ala-Gln), carbohydrates, and antioxidants would modulate duodenal protein metabolism in healthy humans. Design:Thirty healthy control subjects were included and, over a period of 5 h, received by nasogastric tube either saline or ONS providing 11.7 kcal/kg as 0.877 g Ala-Gln/kg, 3.9 g carbohydrates/kg, and antioxidants (29.25 mg vitamin C/kg, 9.75 mg vitamin E/kg, 195 μg β-carotene/kg, 5.85 mg Se/kg, and 390 μg Zn/kg) or glutamine (0.585 g/kg, 2.34 kcal/kg). Simultaneously, a continuous intravenous infusion of l-[1-13C]-leucine was done until endoscopy. Leucine enrichment was assessed by using gas chromatography–mass spectrometric analysis, and mucosal fractional synthesis rate was calculated by using intracellular amino acid enrichment as precursor. Mucosal proteolytic pathways were also evaluated. Results:ONS infusion resulted in a doubling increase (P < 0.01) of duodenal fractional synthesis rate and a significant (P < 0.05) decrease in cathepsin D–mediated proteolysis compared with saline, whereas proteasome and Ca2+-dependent activities were unaffected. ONS infusion significantly (P < 0.01) decreased duodenal glutathione but not glutathione disulfide concentrations or the ratio of glutathione to glutathione disulfide. Insulinemia increased after ONS infusion, whereas plasma essential amino acids decreased. Infusion of glutamine alone did not reproduce ONS effects. Conclusions:ONS infusion improves duodenal protein balance in healthy humans. Further investigations are needed to study the origin of these effects and to evaluate ONS supply in stressed persons.

The Muscle Protein Synthetic Response to the Ingestion of a Plant-Derived Protein Blend Does Not Differ from an Equivalent Amount of Milk Protein in Healthy Young Males

Plant-derived proteins are considered to have lesser anabolic properties when compared with animal-derived proteins. The attenuated rise in muscle protein synthesis rates following ingestion of plant-derived compared with animal-derived protein has been, at least partly, attributed to deficiencies in specific amino acids such as leucine, lysine, and/or methionine. Combining different plant-derived proteins could provide plant-derived protein blends with a more balanced amino acid profile. This study aimed to compare postprandial muscle protein synthesis rates following the ingestion of 30g milk protein with a 30 g blend combining wheat, corn, and pea protein in healthy young men. In a randomized, double-blind, parallel-group design, 24 young males (aged 24±4 y) received a primed continuous l-[ring-13C6]-phenylalanine infusion after which they ingested 30g milk protein (MILK) or a 30 g plant-derived protein blend combining 15g wheat, 7.5g corn, and 7.5g pea protein (PLANT-BLEND). Blood and muscle biopsies were collected frequently for 5h to assess postprandial plasma amino acid profiles (secondary outcome) and subsequent muscle protein synthesis rates (primary outcome). Data were analyzed by 2-factor repeated measures ANOVA and 2-samples t tests. MILK increased plasma essential amino acid concentrations more than PLANT-BLEND over the 5 h postprandial period (incremental AUC = 151 ± 31compared with 79±12 mmol·300 min·L-1, respectively; P<0.001). Ingestion of both MILK and PLANT-BLEND increased myofibrillar protein synthesis rates (P<0.001), with no significant differences between treatments (0.053±0.013%/h and 0.064±0.016%/h, respectively; P=0.08). Ingestion of 30g plant-derived protein blend combining wheat-, corn-, and pea-derived protein increases muscle protein synthesis rates in healthy young males. The muscle protein synthetic response to the ingestion of 30g of this plant-derived protein blend does not differ from the ingestion of an equivalent amount of a high-quality animal-derived protein.Clinical trial registry number for Nederlands Trial Register: NTR6548 (https://trialsearch.who.int/Trial2.aspx?TrialID=NTR6548).

Raw Eggs To Support Postexercise Recovery in Healthy Young Men: Did Rocky Get It Right or Wrong?

Egg protein is ingested during recovery from exercise to facilitate the postexercise increase in muscle protein synthesis rates and, as such, to support the skeletal muscle adaptive response to exercise training. The impact of cooking egg protein on postexercise muscle protein synthesis is unknown. We sought to compare the impact of ingesting unboiled (raw) compared with boiled eggs during postexercise recovery on postprandial myofibrillar protein synthesis rates. In a parallel design, 45 healthy, resistance-trained young men (age: 24 y; 95% CI: 23, 25 y) were randomly assigned to ingest 5 raw eggs (∼30 g protein), 5 boiled eggs (∼30 g protein), or a control breakfast (∼5 g protein) during recovery from a single session of whole-body resistance-type exercise. Primed continuous l-[ring-13C6]-phenylalanine infusions were applied, with frequent blood sampling. Muscle biopsies were collected immediately after cessation of resistance exercise and at 2 and 5 h into the postexercise recovery period. Primary (myofibrillar protein synthesis rates) and secondary (plasma amino acid concentrations) outcomes were analyzed using repeated-measures (time × group) ANOVA. Ingestion of eggs significantly increased plasma essential amino acid (EAA) concentrations, with 20% higher peak concentrations following ingestion of boiled compared with raw eggs (time × group: P < 0.001). Myofibrillar protein synthesis rates were significantly increased during the postexercise period when compared with basal, postabsorptive values in all groups (2-4-fold increase: P < 0.001). Postprandial myofibrillar protein synthesis rates were 20% higher after ingesting raw eggs [0.067%/h; 95% CI: 0.056, 0.077%/h; effect size (Cohen d): 0.63], and 18% higher after ingesting boiled eggs (0.065%/h; 95% CI: 0.058, 0.073%/h; effect size: 0.69) when compared with the control breakfast (0.056%/h; 95% CI: 0.048, 0.063%/h), with no significant differences between groups (time × group: P = 0.077). The ingestion of raw, as opposed to boiled, eggs attenuates the postprandial rise in circulating EAA concentrations. However, postexercise muscle protein synthesis rates do not differ after ingestion of 5 raw compared with 5 boiled eggs in healthy young men. This trial was registered at the Nederlands Trial Register as NL6506 (www.trialregister.nl).