Amino Acid Supply Research Articles

Long-chain n-3 PUFA ingestion for the stimulation of muscle protein synthesis in healthy older adults.

This review aims to critically evaluate the efficacy of long-chain ո-3 PUFA ingestion in modulating muscle protein synthesis (MPS), with application to maintaining skeletal muscle mass, strength and function into later life. Ageing is associated with a gradual decline in muscle mass, specifically atrophy of type II fibres, that is exacerbated by periods of (in)voluntary muscle disuse. At the metabolic level, in otherwise healthy older adults, muscle atrophy is underpinned by anabolic resistance which describes the impaired MPS response to non-pharmacological anabolic stimuli, namely, physical activity/exercise and amino acid provision. Accumulating evidence implicates a mechanistic role for n-3 PUFA in upregulating MPS under stimulated conditions (post-prandial state or following exercise) via incorporation of EPA and DHA into the skeletal muscle phospholipid membrane. In some instances, these changes in MPS with chronic ո-3 PUFA ingestion have translated into clinically relevant improvements in muscle mass, strength and function; an observation evidently more prevalent in healthy older women than men. This apparent sexual dimorphism in the adaptive response of skeletal muscle metabolism to EPA and DHA ingestion may be related to a greater propensity for females to incorporate ո-3 PUFA into human tissue and/or the larger dose of ingested ո-3 PUFA when expressed relative to body mass or lean body mass. Future experimental studies are warranted to characterise the optimal dosing and duration of ո-3 PUFA ingestion to prescribe tailored recommendations regarding n-3 PUFA nutrition for healthy musculoskeletal ageing into later life.

80 Precision Nutrition to Enhance Poultry Performance and Health: the Role of Functional Amino Acids

Abstract Dietary amino acids drive the performance and meat yield of modern broiler strains, and as such, amino acids are among the most economically important nutrients in poultry feeds. At the same time, minimizing N excretion is an increasingly prevalent sustainability target for poultry producers across the world, and this goal is often pursued by feeding reduced crude protein diets. Moreover, poultry production has largely transitioned away from the use of in-feed antibiotic growth promoters, bringing attention to the impact of dietary protein and amino acid levels on the intestinal and overall health of broilers. In response to these dynamic scenarios, research from our lab and others has attempted to more precisely link dietary supply of essential and non-essential amino acids with their functional needs for broilers subjected to various pathogenic and environmental stressors. This presentation will address existing research and knowledge gaps related to functional amino acids in the context of precision nutrition to enhance poultry performance and health.

79 Functional Amino Acids in Dogs and Cats: Implications for Overall Health

Abstract The majority of pets depend exclusively on commercial pet food supplied by their owners, who now more than ever are looking for diets supporting the health and well-being of their companion animals. Due to the diverse roles of amino acids beyond protein synthesis, their use as functional nutrients in canine and feline nutrition has gained attention. Dietary supplementation of tryptophan or tyrosine, as the precursors of serotonin and catecholamines, respectively, may reduce stress, anxiety-related and agonistic behavior in dogs. Surplus dietary arginine may also confer benefits by improving cognitive function in aging dogs likely through the enhancement of nitric oxide synthesis. In adult cats, phenylalanine has been studied for its potential effect on delaying gastric emptying and promoting satiety, which could aid in prevention of feline obesity. On the other hand, diets with greater dietary lysine:calorie may protect lean body mass of senior cats, and thus, may help combat sarcopenia. Studies investigating the functional role of amino acids in dogs and cats, however, are limited and the results are often conflicting. Additionally, data on empirical determination of amino acid requirements in adult dogs and cats are scarce, potentially preventing the dietary delivery of the ideal ratios of amino acids and subsequently the provision of specific amino acids in targeted doses above the requirement to evaluate their potential functional roles. Consequently, although the functional properties of some amino acids in dogs and cats are promising, more research focusing not only on their potential health benefits, but also on the empirical determination of amino acid requirements in dogs and cats is warranted to promote their use as functional nutrients in pet food.

62 Sulphur Amino Acids: Assessing Requirements and Utilization in Dogs and Cats

Abstract Methionine (Met), cyst(e)ine (Cys), homocysteine and taurine are the four sulfur-containing amino acids. Met can serve as a substrate for protein synthesis or to produce homocysteine, which can be remethylated to Met or irreversibly catabolized to Cys. Unlike dogs, cats are unable to further metabolize Cys to taurine, making the latter an indispensable amino acid for the cat. Met, on the other hand, is a dietary indispensable amino acid for all mammals with Cys having the ability to spare part of the Met requirement (total sulfur amino acid requirement; Met + Cys). The amount of Met that cannot be replaced by Cys is defined as the Met requirement (NRC, 2006). Empirical determinations of the Met requirement in adult dogs and cats are still limited and the recommendations proposed by the NRC (2006) are based on studies that used insensitive techniques for mature animals. When a more robust technique, the indicator amino acid oxidation, and more practical experimental diets were used to empirically determine the Met requirement, a greater estimate was found in adult cats (Pezzali et al., 2022) and adult Labrador Retrievers and Beagles, but not in miniature Dachshunds (Mansilla et al., 2020), compared with the current recommendations proposed by the NRC (2006) and AAFCO (2023). Harrison et al. (2020), however, found a decreased estimate for the Met requirement in adult Labrador Retrievers compared with Mansilla et al. (2020), likely due to differences in experimental design and diet composition. This discrepancy highlights the need to standardize methodologies and to investigate the effect of other dietary factors on the Met and total sulfur amino acid requirements owing to their complex metabolism. Indeed, the metabolism of sulfur amino acids may differ between dog breeds, resulting in differences in Met requirements and potentially making taurine a conditionally indispensable amino acid in some breeds under specific dietary conditions. While dietary Met is usually provided in excess in commercial diets, excess of Met may lead to hyperhomocysteinemia, which has been associated with detrimental health effects in other species. Due to the complex metabolism of sulfur amino acids and the complex matrix of pet foods, determining the ideal provision of sulfur amino acids in commercial diets to maximize animal health is a challenge. More long-term studies investigating the effect of different doses and ratios (Met:Cys) of sulfur amino acids on overall metabolism are necessary, in addition to requirement studies, to optimize the dietary delivery of sulfur amino acids in dogs and cats.

PSI-29 Effects of Dietary Intake on Amino Acid Composition of Histotroph (Uterine Luminal fluid) in Nonpregnant Cows: Implications for Pregnancy

Abstract When the developing embryo enters the uterus, before the placenta develops, the embryo receives nourishment from endometrially derived histotroph produced by the uterine glands that remain functional throughout gestation. Throughout pregnancy, this histotroph remains necessary for proper embryonic development. Maternal nutrition may affect histotroph composition resulting in altered embryo development. The objectives were to determine the effects of dietary intake on histotroph amino acid (AA) concentrations. Eighteen multiparous nonpregnant cows (initial BW = 597 kg) were housed at the North Dakota State University Animal Nutrition and Physiology Center (n = 6 cows/pen). Cows were individually fed a TMR once daily via a Calan feeding system and had ad libitum access to fresh water. Cows were randomly assigned to 1 of 2 treatments (n = 9/treatment): dietary intake designed to maintain body weight (CON) or dietary intake designed to lose body weight at a moderate rate (-0.7 kg/d; NEG), for 63 days. Slaughter group 1 contained 4 CON and 5 NEG cows, and group 2 contained 5 CON and 4 NEG cows. Cows were estrus-synchronized with the Co-Synch + CIDR protocol to ensure a common day of the estrous cycle at the time of slaughter (3 d after completion of the Co-Synch + CIDR protocol). When total uterine histotroph AA was calculated (luteal + non-luteal horns) and analyzed by treatment with group in the model, the differences were: CON > NEG for 1) Trp as % of essential AA, and 2) Ser as % of total AA (P = 0.04 and 0.05, respectively). Tendencies for total tract histotroph were observed for Phe and Trp as a % of total AA (P = 0.07 and 0.06, respectively) for CON > NEG. Luteal histotroph Ser as a % of total AA was greater (P = 0.05) for CON vs. NEG. When evaluating non-luteal histotroph, CON had greater (P < 0.05) Cys as a % of total AA compared with NEG cows. Non-luteal histotroph Arg concentration tended (P = 0.10) to be greater for NEG vs. CON. These results demonstrate that feed intake affects cow AA supply in the uterine histotroph, and these AA (Trp, Ser, Phe, Cys and Arg) may function in critical nutrient pathways, reproductive tract vascularization, and antioxidant production, which are necessary for optimal fetal development.

Neurocritical Care Nutrition: Unique Considerations and Strategies for Optimizing Energy Supply and Metabolic Support in Critically Ill Patients

Neuro-critically ill patients face unique challenges in nutritional support due to varying metabolic and energy demands arising from clinical situations such as elevated intracranial pressure, trauma, stroke, epilepsy, targeted temperature management (TTM), and pharmacological interventions. Despite these challenges, there is a lack of systematic reviews addressing their specific needs. This study conducts a systematic review and narrative synthesis of the existing literature on nutritional support for neuro-critical patients, focusing on amino acids that act as neurotransmitters or their precursors. We examined nutritional requirements and timing in patients with stroke and traumatic brain injury, as well as energy and metabolic demands during TTM, a common therapeutic intervention in neuro-critical care. Our review aims to clarify uncertainties surrounding amino acid provision in neuro-critical patients and provide up-to-date recommendations on nutritional support for those with elevated intracranial pressure and undergoing TTM, serving as a foundation for future research and evidence-based guideline development. Key findings include the potential benefits of branched-chain amino acids (BCAAs) in neuro-critical care, the roles of methionine and serine, the significance of arginine in vascular constriction, the controversial role of glutamate in nutrition, and the potential benefits of selenium supplementation. We also discussed special considerations in nutritional support for neuro-critical patients, such as changes in energy demand, the influence of sedation on energy demand, and metabolism changes during TTM. Our review highlights the need for a better understanding of the unique metabolic requirements of neuro-critical patients and the development of evidence-based guidelines for optimal nutritional support in this population.

15 Industry Perspective on the Value and Challenges of Amino Acid Feeding in Ruminants

Abstract The focus of this presentation is to provide a perspective on the value and challenges to meeting the amino acid needs of ruminant livestock based on experiences in the feed manufacturing and ruminant feeding industries. Monogastric nutritionists have demonstrated extensively the value of having an ideal amino acid profile from the point of growth, efficiency, and environmental stewardship. For the ruminant animal, the challenges of protein fractionation, deamination and re-synthesis of amino acids in the rumen create greater complexity both for research advancement as well as practical application to delivery of amino acid technology. In this presentation, amino acid supplies, protein synthesis, the impact of overlaid growth-promoting technologies, and return relative to investment of amino acid-feeding technology will be discussed. In addition to discussing the biological and economic aspects of amino acid feeding, thoughts on the means of delivering amino acid technology within the constraints of feed manufacturing and feeding practices common to ruminant livestock will be discussed. As genetics for improved lean growth in cattle continue to evolve, amino acid nutrition should be at the forefront of investigation of nutritional technologies which allow the improvement in genetic potential to be fully expressed. In addition to the potential value that amino acid feeding brings to ruminant livestock growth and efficiency, it also stands to merit environmental stewardship within this industry.

14 Predicting Performance Responses of Growing Cattle to Amino Acid Supplementation

Abstract Amino acid utilization by cattle can be studied by: 1) assessing amino acid requirements with foundational research and using the resultant information to predict animal performance, or 2) evaluating changes in animal performance in response to changes in amino acid supply and subsequently using those measures to predict amino acid requirements. Neither approach has yielded definitive results, and our ability to predict responses of cattle to amino acid supplementation is still quite limited after many years of research. Most supplementation studies have focused on methionine and lysine, amino acids for which ruminally protected products are commercially available. Most finishing cattle fed diets typical of the U.S. feedlot industry are not responsive to methionine or lysine supplementation, although little research is available for cattle fed beta-agonists. In some cases, growing cattle fed corn-based diets have demonstrated performance responses to lysine supplementation. Growing cattle fed forage-based diets, particularly those based on grass silages, appear responsive to supplemental amino acids. Numerous studies with Holstein steers (150 to 250 kg) maintained in a research model to make amino acids the most limiting nutrient have demonstrated linear increases in nitrogen retention, followed by a plateau, when limiting amino acids were supplemented. From those studies, maintenance requirements for amino acids appear to be small, and efficiencies of amino acid utilization for growth are less than predicted by NASEM (2016). Some factors that would be expected to increase the likelihood that amino acids are the most limiting nutrient include: decreased body weight, greater mature body weight, environments that minimize maintenance energy requirements, and diets that lead to redued amounts of microbial protein synthesis (energy sources such as fat and ruminally resistant starch). Despite the many unknowns associated with amino acid requirements of cattle for growth, potential exists to use amino acid supplementation to improve economics of cattle performance or reduce environmental impacts of cattle production.

Characteristics of amino acid metabolism in colorectal cancer.

In recent years, metabolomics research has become a hot spot in the screening and treatment of cancer. It is a popular technique for the quantitative characterization of small molecular compounds in biological cells, tissues, organs or organisms. Further study of the tumor revealed that amino acid changes may occur early in the tumor. The rapid growth and metabolism required for survival result in tumors exhibiting an increased demand for amino acids. An abundant supply of amino acids is important for cancer to maintain its proliferative driving force. Changes in amino acid metabolism can be used to screen malignant tumors and improve therapeutic outcomes. Therefore, it is particularly important to study the characteristics of amino acid metabolism in colorectal cancer. This article reviews several specific amino acid metabolism characteristics in colorectal cancer.

Nutritional regulation of skeletal muscle energy metabolism, lipid accumulation and meat quality in pigs.

The quality of pork determines consumers' purchase intention, which directly affects the economic value of pork. Minimizing the proportion of inferior pork and producing high quality pork are the ultimate goals of the pig industry. Muscle energy metabolism, serving as a regulative hub in organism energy expenditure and storage as a fat deposit, is compatible with myofiber type composition, affecting meat color, intramuscular fat content, tenderness, pH values and drip loss. Increasing data illustrate that dietary nutrients and bioactive ingredients affect muscle energy metabolism, white adipose browning and fat distribution, and myofiber type composition in humans, and rodents. Recently, some studies have shown that modulating muscle energy metabolism and lipid accumulation through nutritional approaches could effectively improve meat quality. This article reviews the progress and development in this field, and specifically discusses the impacts of dietary supply of amino acids, lipids, and gut microbiota as well as maternal nutrition on skeletal muscle energy metabolism, lipid accumulation and meat quality of pigs, so as to provide comprehensive overview with respect to effective avenues for improving meat quality.

The Use of Standardized Solutions Instead of Individualized Prescriptions for Parenteral Nutrition on the Neonatal Intensive Care Unit in UZ Brussel: A Feasibility Study.

For parenteral nutrition (PN) of newborns, the European Society for Paediatric Gastroenterology Hepatology and Nutrition (ESPGHAN) 2018 guidelines recommend standardized solutions over individual PN (IPN) solutions for most patients. This retrospective study assessed if a shift from IPN to standardized PN was feasible at the UZ Brussel. Using prescription data of 145 neonates, we calculated the nutrient provision for IPN and for standardized PN of the same volumes. We compared the macronutrient intakes with ESPGHAN 2018 recommendations to assess the feasibility. For neonates of a gestational age (GA) <32 or >36 weeks, standardized PN reached recommendations as least as fast as IPN. For neonates with a GA of 32 to 36 weeks, the administration protocol requires further adjustments as amino acid provision was lacking compared to IPN. Overall, the results support the feasibility of a shift from IPN to standardized PN at the UZ Brussel.

Rumen-protected lysine supplementation improved amino acid balance, nitrogen utilization and altered hindgut microbiota of dairy cows

This study was conducted to evaluate the effects of dietary crude protein (CP) and rumen-protected lysine (RPL) supplementation on lactation performance, amino acid (AA) balance, nitrogen (N) utilization and hindgut microbiota in dairy cows. Treatments were in a 2 × 2 factorial arrangement, and the main effects were CP concentration (16% vs. 18%) and RPL supplementation (with or without RPL at 40 g/cow per day). Forty cows were randomly allocated to 4 groups: low-CP diet (LP), low-CP diet plus RPL (LPL), high-CP diet (HP), high-CP diet plus RPL (HPL). The experiment was conducted for 8 weeks. Results showed that RPL increased the dry matter intake (P < 0.01), milk protein yield (P = 0.04) and energy corrected milk (P = 0.04), and tended to increase milk fat yield (P = 0.06) and fat corrected milk (P = 0.05). Cows in the HP group tended to have higher milk urea N (P = 0.07). Plasma concentrations of Arg, Ile, Lys, Met, Pro, total essential AA and total nonessential AA were increased by RPL (P < 0.05). The total essential AA, total nonessential AA and most AA (except Ile, Phe, Gly and Pro) were increased in the HP group (P < 0.05). N excretion was increased in the HP group through an increase in urea N excretion (P < 0.01) and an upward trend in plasma urea N (P = 0.07). In addition, RPL tended to increase milk protein N secretion (P = 0.08), milk N (P = 0.07) and microbial protein synthesis (P = 0.06), and decreased plasma urea N (P < 0.001). In the hindgut, the bacterial community were different between the LP and LPL groups (P < 0.01). The probiotic abundances of Christensenellaceae_R-7_group and Acinetobacter were increased by RPL (P = 0.03 and 0.03, respectively). The pathogenic abundances of Clostridium_sensu_stricto_1 (P < 0.001) and Turicibacter (P < 0.01) were decreased by RPL. In conclusion, supplementing RPL with low dietary CP could balance AA supply and increase milk protein yield, resulting in an improvement in N utilization efficiency, and altered the composition of the hindgut microbiota to favor the lactation performance of dairy cows.

Arginine-depleting Enzymes, A Potential Treatment Option for Tumors With Arginine Auxotrophy : A Review

The World Health Organization reports that one of the top global causes of illness and mortality is cancer, with nearly 10 million deaths in 2020. Changes in cellular metabolism are common characteristics of a wide variety of malignancies. Enzymatic deficits cause many tumors to lose the ability to synthesize amino acids required for their growth, survival, or proliferation. Thus, some tumors depend on the extra-cellular supply of specific amino acids to meet their needs, allowing them to survive. Amino acid depletion as a targeted therapy takes advantage of these tumor traits by depleting certain amino acids in the body that is required for the tumor to survive. This review aims to discuss the potential and challenges of arginine-depleting enzymes as a means in treating arginine auxotrophic cancers. Previously, arginine deiminase (ADI) of bacterial origin has been studied for the in vivo arginine auxotrophic tumour therapy. However, it has been hampered by drawbacks, including immunogenicity and toxicity issues. Thus, human arginase I (hARGI) has been considered a better candidate due to its low mmunogenicity and toxicity effects. However, hARGI’s application as an anti-cancer drug is hindered by its low activity towards arginine owing to its high Km values indicating the enzyme’s low substrate affinity. Thus, it is necessary to improve the enzyme catalytic capability and stability for more practical application in therapeutic cancer treatment. With the advancement of bioinformatics tools, more studies are anticipated to rationally engineer the enzyme for more practical clinical application in the treatment of arginine auxotrophic cancers.

Microbial gene expression during hibernation in arctic ground squirrels: greater differences across gut sections than in response to pre-hibernation dietary protein content.

Obligate seasonal hibernators fast for 5-9months depending on species yet resist muscle atrophy and emerge with little lean mass loss. The role of the gut microbiome in host nitrogen metabolism during hibernation is therefore of considerable interest, and recent studies support a role for urea nitrogen salvage (UNS) in host-protein conservation. We were interested in the effect of pre-hibernation diet on UNS and the microbial provision of essential amino acids (EAAs) during hibernation; therefore, we conducted a study whereby we fed arctic ground squirrels (Urocitellus parryii) pre-hibernation diets containing 9% vs. 18% protein and compared the expression of gut bacterial urease and amino acid (AA) metabolism genes in 4 gut sections (cecum mucosa, cecum lumen, small intestine [SI] mucosa, and SI lumen) during hibernation. We found that pre-hibernation dietary protein content did not affect expression of complete bacterial AA pathway genes during hibernation; however, several individual genes within EAA pathways were differentially expressed in squirrels fed 18% pre-hibernation dietary protein. Expression of genes associated with AA pathways was highest in the SI and lowest in the cecum mucosa. Additionally, the SI was the dominant expression site of AA and urease genes and was distinct from other sections in its overall microbial functional and taxonomic composition. Urease expression in the gut microbiome of hibernating squirrels significantly differed by gut section, but not by pre-hibernation dietary protein content. We identified two individual genes that are part of the urea cycle and involved in arginine biosynthesis, which were significantly more highly expressed in the cecum lumen and SI mucosa of squirrels fed a pre-hibernation diet containing 18% protein. Six bacterial genera were responsible for 99% of urease gene expression: Cupriavidus, Burkholderia, Laribacter, Bradhyrizobium, Helicobacter, and Yersinia. Although we did not find a strong effect of pre-hibernation dietary protein content on urease or AA metabolism gene expression during hibernation, our data do suggest the potential for pre-hibernation diet to modulate gut microbiota function during hibernation, and further investigations are warranted.

Toward the Development of Potentially Healthy Low-Energy-Density Snacks for Children Based on Pseudocereal and Pulse Flours.

The main objective of this study was the development of gluten-free cracker-type snacks with a balanced supply of essential amino acids, a lower glycemic index, and a lower caloric intake that were sensorially acceptable. For this purpose, chickpea flour was replaced by quinoa (10, 20, 30, 40, and 50%) and the fat was partially (75%) replaced by chicory inulin. The flours were characterized in terms of their proximate composition, individual mineral content, particle size distribution, and functional properties. The parameters analyzed for the crackers, once baked, were the water content, water activity, weight, dimensions, color, and texture. A sensory analysis was performed as well, using the formulations containing 50% chickpea flour and 50% quinoa flour (g/100 g flour), with and without inulin, as well as those made with 100% chickpea flour. From the analysis of the raw flours, it can be concluded that snack products developed from them could be a nutritive option for children, in terms of the protein, magnesium, and fiber content. The functional properties revealed that both flours are suitable for producing doughs and baked products. The obtained results indicate that snacks made with 50% quinoa flour (g/100 g flour) and 75% chicory inulin (g/100 g high oleic sunflower oil) could be an interesting alternative for children as, in addition to offering a very interesting nutritional contribution, the energy intake from fat is reduced by 57%.

The influence of substituting dietary peptide-bound with free amino acids on nitrogen metabolism and acid-base balance of broiler chickens depends on asparagine and glutamine supply.

Reducing dietary crude protein (CP) concentration while maintaining adequate amino acid (AA) supply by free AA inclusion can contribute to attenuate the negative environmental effects of animal farming. This study investigated upper limits of dietary free AA inclusions without undesirable effects including the dependence on asparagine (Asn) and glutamine (Gln) supply. Ten broilers were allocated to sixty-three metabolism units each and offered nine experimental diets from day (d) 7-21 (n 7). One diet (167 g CP/kg) contained 80 g soya protein isolate (SPI)/kg. In the other diets, 25, 50, 75 and 100 % of the digestible AA from SPI were substituted with free AA. Digestible Asn+aspartic acid (Asp) and Gln+glutamic acid (Glu) were substituted with Asp/Glu or 50/50 mixes of Asp/Asn and Glu/Gln, respectively. Total excreta were collected from d 11-14 and from d 18-21. Growth and nitrogen accretion were unaffected by 25 and 50 % substitution without and with free Asn/Gln, respectively, but decreased at higher substitution (P ≤ 0·024). Circulating concentrations of Asp, Glu and Gln were unaffected by treatment, while Asn decreased at substitution higher than 50 % when Asn/Gln were not provided (P ≤ 0·005). Blood gas analysis on d 21 indicated a compensated metabolic acidosis at substitution higher than 50 and 75 % without and with free Asn/Gln, respectively (P ≤ 0·017). Results suggest that adding Asn/Gln increased an upper limit for proportion of dietary free AA from 10 to 19 % of dietary CP and enabled higher free AA inclusion without affecting the acid-base balance.

Effects of faba bean, blue lupin and rapeseed meal supplementation on amino acid metabolism of dairy cows fed grass silage-based diets.

Information about the amino acid (AA) supply of locally produced protein supplements to dairy cow metabolism is needed to design sustainable diets for milk production. In this dairy cow experiment, grass silage and cereal-based diets supplemented with isonitrogenous amounts of rapeseed meal (RSM), faba beans (FB) and blue lupin seeds (BL) were compared with a control diet (CON) without protein supplementation. The diets were arranged as a 4×4 Latin Square using periods of 21days, and four rumen-cannulated Nordic Red dairy cows were used in the experiment. The intake of all AAs increased in response to protein supplementation and was for many individual AAs higher when RSM rather than the grain legumes FB and BL were fed. The total AA flow at the omasal canal was 3026, 3371, 3373 and 3045g/day for cows fed CON, RSM, FB and BL, respectively, but only RSM resulted in higher milk protein output. This may be explained by the higher provision of essential AA for milk protein synthesis when RSM was fed. The cows fed FB showed some positive features such as a tendency for greater omasal flow of branched-chain AA compared with BL. Overall, low plasma methionine and/or glucose concentrations in all treatments suggest that their supply was possibly limiting further production responses under the dietary conditions of the current study. It seems that the benefits of grain legume supplementation are limited when high-quality grass silage and cereal-based diets are used as the basal diet, but higher responses in amino acid supply and subsequent production responses can be expected when RSM is used.

Review: How the efficiency of utilization of essential amino acids can be applied in dairy cow nutrition.

How the efficiency of utilization of essential amino acids (EffUEAA) can be applied in dairy cow nutrition is presented in this review. The concept of EffUEAA proposed by the National Academies of Sciences, Engineering and Medicine (NASEM, 2021) is first detailed. It represents the proportion of the metabolisable essential amino acids (mEAA) supply used to support protein secretions and accretions (scurf, metabolic fecal, milk and growth). For these processes, the efficiency of each individual EAA is variable, and considered to vary similarly for all the protein secretions and accretions. The anabolic process of gestation is ascribed to a constant efficiency (33%), whereas the efficiency of endogenous urinary loss (EndoUri) is set at 100%. Therefore, the NASEM model EffUEAA was calculated as the sum of EAA in the true protein of secretions and accretions divided by the available EAA (mEAA - EndoUri - gestation net true protein/0.33). In this paper, the reliability of this mathematical calculation was tested through an example where the experimental efficiency of His was calculated assuming that liver removal represents catabolism. The NASEM model and experimental efficiencies were in the same range and varied in similar manner. Assuming that the NASEM model EffUEAA reflects EAA metabolism in the dairy cow, its different applications were examined. In NASEM, target efficiencies were determined for each EAA: 75, 71, 73, 72, 73, 60, 64, 86 and 74% for His, Ile, Leu, Lys, Met, Phe, Thr, Trp, and Val, respectively. From these, recommendations for mEAA supply can be calculated as: [(secretions + accretions)/(target EffUEAA×0.01)+EndoUri+gestation/0.33], assuming energy supply is adequate. In addition to NASEM propositions, equations to predict EffUEAA with precision and accuracy are detailed, using the ratio of (mEAA-EndoUri) to digestible energy intake, in a quadratic model that includes days in milk. Moreover, milk true protein yield predictions from predicted EffUEAA or efficiency of utilization of metabolisable protein are better than those from the multivariate equation of NASEM (2021) and superior to those predicted with a fixed efficiency. Finally, either the NASEM model or the predicted EffUEAA can be used to assess the responsiveness of a ration to supplementation with a single EAA. If the EffUEAA of the EAA to supplement is higher than the target EffUEAA, while the EffUEAA of the other EAA are lower than the target value, this suggests a potential improvement in milk true protein yield to supplementation with this EAA.

Screening Effect of Amino Acid on Xylitol Production By Recombinant Escherichia coli System

Numerical studies have been conducted to sources for safer biological methods to produce xylitol. In view of these concerns and the benefits of xylitol, a fermentation process that is formulated to yield highest xylitol is both favourable and profitable. In this study, recovery of xylitol production from xylose by recombinant Escherichia coli system was conducted by modulating both carbon source and amino acid composition of the media for the relative growth delay of the strain. The key enzyme for xylitol production in this recombinant system is xylose reductase, XR which utilize NADPH to reduce D-xylose to xylitol. By adding 20 types of amino acids individually and substituting glycerol as the carbon source each time, showed an increase of xylitol to 5.24 g/L and yield biomass production to 1.536. It is hypothesize that supply of single amino acid act as a tool to enhance (NAD(P)H)/(NADP+) ratio. Reduced NAD(P)H competition from other bioprocesses help the cell replenishes the reduced cofactor pool. Xylitol has a remarkable benefits as a healthy replacement of table sugar. Therefore, the success of this study will definitely bring forward advance in the production technology and act as a reference for future research.

Processing Enhances Coix Seed Prolamins Structure and Releases Functional Peptides after Digestion: In Silico and In Vitro Studies.

Dipeptidyl peptidase-IV (DPP-IV) is a key target for the treatment of type 2 diabetes mellitus. It is possible that peptides that precisely regulate DPP-IV could be released from coix seed prolamins (CSP), but whether this happens has not yet been investigated. We performed the in silico digestion of CSP and predicted the bioactivity, absorption, transport, toxicity, and allergenicity of the resulting peptides. The simulation predicted that 47 non-toxic bioactive peptides would be released. After screening these, we found that 64.58% of them could possess DPP-IV inhibitory activity. The effect of thermal processing on the amino acid composition and structural properties of CSP was determined, and the DPP-IV inhibitory activity of its digestion-derived peptides was also assessed. The results showed that processing could change the flavour of coix seed and the supply of amino acids. After processing, the spatial conformation of CSP changed from ordered to disordered, and the peptide content and the DPP-IV inhibitory activity of its digestion products significantly increased by 19.89-30.91% and 36.84-42.02%, respectively. These results support the hypothesis that processing can change the protein structure and increase the probability that bioactive peptides will be released. They also have important implications for the development of bioactive peptides and the intensive processing of coix seeds.