Amino Acid Nutrition Research Articles

Technical note: simultaneous determination of amino thiols in pig tissue by ultra-high performance liquid chromatography with fluorescence detection.

Sulfur amino acid nutrition and metabolism are linked to animal disease. While validated methods for the determination of amino thiol levels in plasma or serum are available, there is a dearth of validated methods for their measurement in tissue. A robust and reproducible ultra-high performance liquid chromatography method has been validated for the simultaneous determination of concentrations of cysteine (Cys), cysteinylglycine (CysGly), homocysteine (Hcys), γ-glutamylcysteine (γ-GluCys), and glutathione (GSH) in pig tissue. Tissue was homogenized and deproteinized with trichloroacetic acid. Amino thiols in the acid-soluble fraction of the tissue homogenate were reduced with tris-(2-carboxyethyl)-phosphine hydrochloride and derivatized with 4-(aminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole (ABD-F). Amino thiols were resolved under reversed-phase gradient conditions on a Waters Acquity BEH C18 column (1.7 µm, 2.1 mm × 100 mm) within 4.5 min and detected with fluorescence. The peak area ratio of analyte to 2-mercaptopropionylglycine internal standard, added to external calibration standards and samples, was used to develop linear calibration curves. Linear calibrations were performed over the range of 15-1,500 nmol/g for Cys, CysGly, Hcys, and γ-GluCys and 150-15,000 nmol/g for GSH. Linearity, lower limit of detection, lower limit of quantitation, accuracy, precision, sample stability, and carryover were evaluated. We demonstrate excellent linearity for all analytes within their respective concentration range (r2 > 0.99) and excellent recovery of amino thiols from spiked samples (mean ± SD across tissues; Cys, 100.0 ± 2.2%; CysGly, 95.4 ± 5.1%; Hcys, 96.6 ± 2.0%; γ-GluCys, 102.2 ± 2.7%; and GSH, 100.6 ± 3.3%). The intra-day and inter-day precisions did not exceed 5% and 10%, respectively. Repeated freezing and thawing of tissue homogenate did not affect measured amino thiol concentrations, ABD-labeled amino thiols were stable for 1 wk after derivatization, and there was no sample carryover across consecutive injections. We confirm the identity of each ABD-labeled amino thiol with Orbitrap mass spectrometry. Finally, we apply the method to the determination of amino thiol concentrations in liver and jejunum tissues in newly weaned pigs and show that despite elevated Cys and maintained GSH concentrations in liver, both γ-GluCys and GSH decline in jejunum of weaned pigs.

High-volume pre-dilution on-line hemodiafiltration is the adequate blood purification method from the viewpoint of amino acid nutrition

BackgroundWe compared amino acid leakage among high-volume pre-dilution on-line hemodiafiltration (Pre O-HDF), hemodialysis (HD), and post-dilution on-line hemodiafiltration (Post O-HDF).Subjects and methodsThe subjects were 9 patients. For HD, the total dialysate flow rate was established as 500 mL/min. For high-volume Pre O-HDF, it was established as 600 mL/min, under a replacement fluid volume of 90 L. For Post O-HDF, it was established as 600 mL/min, under a replacement fluid volume of 10 L. In both procedures, the duration of treatment was 4 h, and the blood flow volume was 200 mL/min. We compared the leakages of total amino acid, non-essential amino acid, and essential amino acid, clear spaces (CSs), β2-microglobulin (β2-MG) reduction rate, Kt/V for urea, and albumin leakage among the three procedures.ResultsAmino acid leakages after high-volume Pre O-HDF were significantly lower than HD and Post O-HDF. The CSs after high-volume Pre O-HDF were significantly lower than Post O-HDF. The β2-MG reduction rate after high-volume Pre O-HDF was significantly lower than Post O-HDF. The Kt/V for urea was not significantly different. Albumin leakages were below the detection limit (< 1 g) in the three procedures.ConclusionUnder the treatment conditions we performed this time, high-volume Pre O-HDF reduces amino acid leakage in comparison with HD and Post O-HDF. High-volume Pre O-HDF is a therapeutic mode that suppresses amino acid leakage.

Analysis of Main Tea Characteristic Components and Volatile Components and Amino Acid Nutrition Evaluation of Insect Tea from Three Producing Areas in Guangxi

Analysis of Main Tea Characteristic Components and Volatile Components and Amino Acid Nutrition Evaluation of Insect Tea from Three Producing Areas in Guangxi

Assessment of Amino Acid Nutrition in the Several Peanut (Arachis hypogaea L.) Varieties from Fujian, China

Assessment of Amino Acid Nutrition in the Several Peanut (Arachis hypogaea L.) Varieties from Fujian, China

Comprehensive Utilization of Land Resources for Photovoltaic Power Generation to Culture Chinese Mitten Crab (Eriocheir sinensis): Growth Performance, Nutritional Composition and Tissue Color

The assertive growth of photovoltaics (PV) will occupy a lot of land resources. There is also a needed land resource to expand the culturing area of Eriocheir sinensis. The aquavoltaic systems offer a potential solution to integrate PV power and E. sinensis culturing. In this study, we cultured E. sinensis in an area of PV panels (PV group) and an area with no PV panels (control group), respectively. The results showed that the weight gain rate, body length, body width, and meat yield of male crabs in the PV group significantly increases. In addition, the moisture of muscles, hepatopancreas, and testes in the PV group has significantly increased, and the total lipids of the hepatopancreas and muscles in the PV group were significantly decreased. Moreover, the PV panels affected the content of eight amino acids in different tissues, including Met, Arg, Cys, Pro, Gly, Leu, Tyr, and His. In addition, several saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA) had been significantly influenced by the PV panels. ∑MUFA, docosahexaenoic acid (DHA), ∑n-3 PUFA, ∑n-6 PUFA, and n-3/n-6 PUFA ratio (p &lt; 0.05) in the PV group had significantly decreased. The results of tissue color showed that the L* value of ovaries was significantly higher than in the control group, and a* and b* values of hepatopancreas were significantly lower. In conclusion, PV panels could promote growth performance and amino acid nutrition of crabs. However, the PV panels had a few negative influences on the fatty acid composition and tissue color.

Long-term home parenteral nutrition and profile of amino acids in serum and their loss in urine.

Amino acids are an essential part of parenteral nutrition. This study aimed to determine the serum profile of amino acids and their loss in urine in patients with long-term home parenteral nutrition (HPN) during 12 h of infusion in comparison with similar parameters in the remaining 12 h as well as in healthy participants. We enrolled forty-five patients with long-term HPN for 6-75 (median, 33) months. The indication for HPN was short bowel syndrome secondary to radical resection of the small intestine following complications of Crohn's disease. HPN was administered via two-chamber all-in-one bags prepared in a hospital pharmacy overnight for 12 h each day. The average dose of amino acids, carbohydrates and fats administered was 1·5, 3·4 and 0·68 g/kg per d, respectively, at an infusion rate of 0·11, 0·28 and 0·06 g/kg per h, respectively. The levels of essential amino acids in the serum of the patients were not significantly different from those in healthy individuals; however, of the non-essential amino acids, cystine and glutamine levels were lower and glycine and ornithine levels were higher in the patients (P < 0·05). Excretion of amino acids in the urine during 12 h of infusion at an infusion rate of 0·11 g/kg per h was 301 mg, while it was 104 mg during the remaining 12 h (P < 0·0001). Our patients on long-term HPN had a normal serum profile of essential amino acids. The total urinary excretion of amino acids during 12 h of infusion accounted for only 0·34 % (0·23-0·46) of the administered dose.

Impact of Amino Acids Nutrition Following Gastrectomy in Gastric Cancer Patients.

Postoperative body weight loss (BWL) and skeletal muscle loss (SML) after gastrectomy are associated with a decline in quality of life and worse longterm prognosis in gastric cancer (GC) patients. This study aimed to evaluate the efficacy of amino acids nutrition on BWL and SML in the early period following gastrectomy. The parameters of body composition were measured by bioelectrical impedance analysis in the patients undergoing radical gastrectomy for GC and analyzed retrospectively. Patients received either peripheral parenteral nutrition (PPN) of 4.3% glucose fluid with regular diet (control group, n=43) or PPN of 7.5% glucose fluid containing amino acids plus oral nutritional supplement (ONS) rich in protein with regular diet (amino acids group, n=40) following gastrectomy. The percentages of BWL and SML from preoperative values to those at 7 days and 1 month after surgery were compared between the two groups. The %BWL and %SML at 7 days after surgery were significantly lower in the amino acids group than those in the control group (%BWL, -2.4±1.7% vs. -4.2±1.8%; p<0.0001, %SML, -4.1±3.8 vs. -6.5±3.8; p=0.006). Moreover, the %BWL at 1 month after surgery was significantly lower in the amino acids group compared to that in the control group (- 4.6±2.9% vs. -6.1±2.6%; p=0.01); however, the %SML was similar between the two groups. The hematological nutritional parameters were similar between the two groups. Amino acids nutrition by PPN and ONS following gastrectomy prevented postoperative BWL and SML in the early period after surgery in GC patients.

Meta-Analysis of Rumen-Protected Methionine in Milk Production and Composition of Dairy Cows.

Simple SummaryIn terms of amino acid nutrition of dairy cows, many scholars have shown that adding rumen-protected methionine to dairy cow feed can improve milk yield and milk components such as milk protein, lactose and milk fat, but the research of some scholars is inconsistent. This paper aims to summarize and analyze all the research contents through meta-analysis and comprehensively understand the impact of rumen-protected methionine on the milk yield and milk composition of dairy cows. The results show that adding rumen-protected methionine to cow feed did not significantly improve milk yield nor the lactose concentration in milk but did improve the fat and protein concentrations in milk, and the effects were better in the high-protein feed than that in the low-protein feed.This study aims to evaluate the influence of rumen-protected methionine (RPM) on the milk yield and milk compositions of dairy cows by employing a meta-analysis method. The articles in the publication databases between January 2010 and January 2022 which reported on various concentrations of RPM supplements in dairy cow diets and then monitored the milk yield and milk compositions were searched. A total of 14 studies were included, covering 27 treatments with a total of 623 dairy cows. Comprehensive Meta-Analysis V3 was used for statistical analysis, the forest map was drawn by the standard mean difference (SMD) with a 95% confidence interval (95% CI), and the SMD was calculated by a random effect model. The dose effect curve was drawn by fitting the SMD and RPM dose of each study to explore the optimal dosage of RPM. Compared with the basal diet, the RPM supplement significantly increased the percentages of milk fat (SMD (95% CI): 1.017% [0.388, 1.646]) and milk protein (SMD (95% CI): 0.884 [0.392, 1.377]). However, the milk yield (SMD (95% CI): 0.227 kg/d [−0.193, 0.647]) and lactose concentration (SMD (95% CI): 0.240% [−0.540, 1.020]) were not affected. The subgroup analysis found that the effect of the RPM supplement on the milk fat and milk protein was greater in the high-protein feed than in the low-protein feed. Multiple regression analysis showed that feeding RPM significantly improved the milk yield and milk protein percentage of dairy cows. The results of the dose–effect analysis show that the optimal range for the RPM was 7.5–12.5 g/d. RPM supplements in a dairy diet can improve the milk protein percentages and milk fat percentages of dairy cows.

Response surface optimization of millet milk fermented by Lactobacillus kefir

Based on the amino acid score (AAS), chemical score (CS), and amino acid proportional coefficient score (SRCAA) as evaluation indicators, millet powder, whey protein isolate powder, and soybean protein isolate powder were mixed to make millet compound powder. After the millet compound powder and water were uniformly mixed at a material-to-liquid ratio of 1:20, the kefir fermented millet nutritional milk was prepared by beating, gelatinizing, liquefying, saccharifying, and fermenting. The protein content, polyphenol content, viable count and acidity of kefir millet fermented milk were significantly higher than those of the other two commercially available similar beverages. The scavenging rates of DPPH free radicals and hydroxyl radicals in the kefir millet fermented milk group at three stages (before undigested, after gastric digestion for 2.5 h, and after intestinal digestion for 2.5 h) were significantly higher than those in the unfermented millet pulp group. Novelty impact statement In this study, based on the amino acid pattern and amino acid nutrition evaluation methods (AAS, CS, SRCAA), millet flour and two protein powders with rich lysine content (whey protein isolate powder and soybean protein isolate powder) were rationally compounded as amino acid balanced millet compound powder. The millet compound powder is fermented by Lactobacillus kefir into millet nutritional fermented milk with unique flavor of probiotic fermentation. The antioxidant activity of millet nutritional fermented milk and millet pulp before fermentation was compared and analyzed by gastrointestinal digestion simulation in vitro, and it was determined that millet nutritional fermented milk had strong antioxidant activity.

PSVIII-6 Animal Science’s Challenge and Opportunity

Abstract Knowledge of the global epidemic of metabolic syndrome provides animal scientists with an opportunity to improve their health and that of their communities; increase awareness and support of their disciplines and efforts; and support truly sustainable food systems and economic development. This presentation will expand these arguments. Professionals within the disciplines of animal science must push back against those who oppose animal agriculture, particularly by refuting the dietary messaging accusing animal source foods of being health hazards. Official dietary policy for almost half a century has been explicitly anti-animal products, despite a growing body of scientific evidence refuting these recommendations. Animal science undergraduates receive more training in nutrition than medical students. Animal nutrition is a functional scientific discipline. Swine nutritionists have a more advanced understanding of amino acid nutrition in monogastrics than many human nutritionists. Human nutrition has necessarily relied on observational studies, which are widely recognized as being of low scientific quality. Serious conflicts of interests exist within the field of human nutrition. The leadership of the human nutrition community has failed to: acknowledge the weak scientific basis of their dietary guidance; incorporate the highest-quality scientific evidence available into their guidance and policies; and address a global epidemic – metabolic syndrome (hyperinsulinemia and insulin resistance). According to the CDC, more than 34% of adults in the Midwestern US region are obese (Body Mass Index ³ 30). Odds are that a significant proportion of our fellow Midwest Section members are afflicted with metabolic syndrome, most of them unaware of their condition and its risks. Likewise in the communities we serve. We have an opportunity, and in light of the failures of human nutrition, a responsibility to: stop accepting their pronouncements; stop citing them in our research; and challenge their legitimacy wherever possible.

Biomarkers and De Novo Protein Design Can Improve Precise Amino Acid Nutrition in Broilers.

Simple SummaryAlmost half of the protein ingested by broilers is not retained and is excreted, impairing the nitrogen utilization, health and productivity of the animals, and intensifying the environmental impact of poultry meat production. This work proposes two potential tools, combining traditional nutrition with biotechnological, metabolomics, computational and protein engineering knowledge, which can contribute to improving precise amino acid nutrition in broilers in the future: (i) the use of serum uric nitrogen content as a rapid biomarker of amino acid imbalances, and (ii) the design and modeling of de novo proteins that are fully digestible and fit exactly to the animal’s requirements. Both tools can open up new opportunities to form an integrated framework for precise amino acid nutrition in broilers, helping us to achieve more efficient, resilient, and sustainable production. This information can help to determine the exact ratio of amino acids that will improve the efficiency of the use of nitrogen by poultry.Precision nutrition in broilers requires tools capable of identifying amino acid imbalances individually or in groups, as well as knowledge on how more digestible proteins can be designed for innovative feeding programs adjusted to animals’ dynamic requirements. This work proposes two potential tools, combining traditional nutrition with biotechnological, metabolomic, computational and protein engineering knowledge, which can contribute to improving the precise amino acid nutrition of broilers in the future: (i) the use of serum uric nitrogen content as a rapid biomarker of amino acid imbalances, and (ii) the design and modeling of de novo proteins that are fully digestible and fit exactly to the animal’s requirements. Each application is illustrated with a case study. Case study 1 demonstrates that serum uric nitrogen can be a useful rapid indicator of individual or group amino acid deficiencies or imbalances when reducing dietary protein and adjusting the valine and arginine to lysine ratios in broilers. Case study 2 describes a stepwise approach to design an ideal protein, resulting in a potential amino acid sequence and structure prototype that is ideally adjusted to the requirements of the targeted animal, and is theoretically completely digestible. Both tools can open up new opportunities to form an integrated framework for precise amino acid nutrition in broilers, helping us to achieve more efficient, resilient, and sustainable production. This information can help to determine the exact ratio of amino acids that will improve the efficiency of the use of nitrogen by poultry.

52 Metabolic Syndrome: Animal Science’s Challenge and Opportunity

Abstract Knowledge of the global epidemic of metabolic syndrome provides animal scientists with an opportunity to improve their health and that of their communities; increase awareness and support of their disciplines and efforts; and support truly sustainable food systems and economic development. This presentation will expand these arguments. Professionals within the disciplines of animal science must push back against those who oppose animal agriculture, particularly by refuting the dietary messaging accusing animal source foods of being health hazards. Official dietary policy for almost half a century has been explicitly anti-animal products, despite a growing body of scientific evidence refuting these recommendations. Animal science undergraduates receive more training in nutrition than medical students. Animal nutrition is a functional scientific discipline. Swine nutritionists have a more advanced understanding of amino acid nutrition in monogastrics than many human nutritionists. Human nutrition has necessarily relied on observational studies, which are widely recognized as being of low scientific quality. Serious conflicts of interests exist within the field of human nutrition. The leadership of the human nutrition community has failed to: acknowledge the weak scientific basis of their dietary guidance; incorporate the highest-quality scientific evidence available into their guidance and policies; and address a global epidemic – metabolic syndrome (hyperinsulinemia and insulin resistance). According to the CDC, more than 34% of adults in the Southern US region obese (Body Mass Index ³ 30). Odds are that a significant proportion of our fellow Southern Section members are afflicted with metabolic syndrome, most of them unaware of their condition and its risks. Likewise in the communities we serve. We have an opportunity, and in light of the failures of human nutrition, a responsibility to: stop accepting their pronouncements; stop citing them in our research; and challenge their legitimacy wherever possible.

Efficiency of using Artemia salina as part of a feed additive for chickens

Main problem: The development of the genetic potential of poultry, as well as the receipt of high-quality eggs for collection or further incubation, are possible only if rational and correct feeding of the broodstock and, more importantly, the young during its rearing period is observed. During this period, high-quality protein nutrition occupies an important place, which determines the level of productivity, stable growth, reproductive ability of the bird, as well as the state of health during the feeding period. Protein deficiency always remains an urgent problem for agricultural land, whose main activity is aimed at breeding dairy and meat animals. In this regard, research in the field of finding the use of non-traditional protein feed is of great need. If we summarize the modern achievements in the field of protein and aminoacid nutrition of poultry, we can find the most profitable way to obtain feed additives in industrial production. The studies, the results of which will be described in this article, are aimed at studying the possibility, experimental substantiation of the optimal dosage and the effectiveness of using the feed additive from crustaceans Artemia salina in the diets of chickens of the egg-meat direction of productivity [1]. Purpose: To study the possibility, experimental substantiation of the optimal dosage and the effectiveness of the use of the feed additive from crustaceans Artemia salina in the diet of chickens of the egg-meat direction of productivity. Methods: Analysis and generalization of theoretical information Results and their significance: This article presents the results of the analysis and generalization of theoretical material. The theoretical significance is determined by the fact that it is invested in scientific and practical problems related directly to solving urgent problems, increasing the efficiency, competitiveness and quality of domestic poultry products.

Influence of alimentary factors on the absorption of feed nutrients and poultry productivity

The article is a summary of the literature on the main aspects of the modern bird feeding system. Theoretical aspects and results of experimental research of scientists on the substantiation of parameters of protein and amino acid nutrition are given, which is an important factor that, under appropriate conditions can significantly guarantee the realization of the genetic potential of corresponding breeds and crosses of poultry. It is shown that an important aspect of protein nutrition is the ratio of feed amino acids. Their negative interaction can be caused by a deficiency of one or more amino acids, an imbalance between them, antagonism, and toxicity. This is accompanied by effects on various physiological and biochemical processes, significantly affects appetite, intestinal absorption, renal reabsorption and transport of amino acids, their catabolism, rate of protein decomposition, synthesis, and formation of toxic metabolic products. The data show that the required level of energy for the bird's body is provided by carbohydrates (mainly of plant origin) and lipids (fat supplements of various origins). It is noted that lipids promote the absorption, transport, and deposition of fat-soluble vitamins. The effectiveness of using fat supplements as energy depends on their source. At the same time, among the indispensable nutrients that have a significant impact on growth intensity, reproductive quality, poultry productivity, and biological value of products, an important role is played by macro-and micronutrients. Many researchers emphasize that along with the use of traditional feeds in poultry feeding, the possibilities of non-traditional cereals rich in protein and lipids are not fully used. A limiting factor in their use is the presence in their composition of anti-nutrients contained in many feeds. Once in the digestive tract of animals, they negatively affect the absorption of feed nutrients. In most cases, the consumption of such feed by animals is manifested in growth retardation, increased feed consumption, hormonal effects, and, less frequently, in the dysfunction of certain organs.

Edamame soybean protein concentrate as a source of amino acid nutrition for poultry

This study aims to determine the opportunity and characteristics of edamame soybean protein concentrate (eSPC) as a source of amino acid. In this study, edamame soybean protein concentrate (eSPC) was manufactured using various methods of manufacturing solvent-based materials. This experiment consisted of two different methods, namely washing with acid and ethanol solvent. The results of manufacturing eSPC were analyzed for nutrients, especially the protein and amino acids contents. From the presentation and description of data, the best results of edamame soybean processing into protein concentrate (eSPC) was obtained in the acid method with a protein content of 48.83% and a total of 36.66% amino acids. The highest content of lysine was obtained at eSPC processing using 3.77% of acid, while methionine highest was with approximately 1.12%. These results showed that the eSPC is well used as a source of lysine and methionine in poultry feed.

PEPT1 is essential for the growth of pancreatic cancer cells: a viable drug target.

PEPT1 is a proton-coupled peptide transporter that is up-regulated in PDAC cell lines and PDXs, with little expression in the normal pancreas. However, the relevance of this up-regulation to cancer progression and the mechanism of up-regulation have not been investigated. Herein, we show that PEPT1 is not just up-regulated in a large panel of PDAC cell lines and PDXs but is also functional and transport-competent. PEPT2, another proton-coupled peptide transporter, is also overexpressed in PDAC cell lines and PDXs, but is not functional due to its intracellular localization. Using glibenclamide as a pharmacological inhibitor of PEPT1, we demonstrate in cell lines in vitro and mouse xenografts in vivo that inhibition of PEPT1 reduces the proliferation of the cancer cells. These findings are supported by genetic knockdown of PEPT1 with shRNA, wherein the absence of the transporter significantly attenuates the growth of cancer cells, both in vitro and in vivo, suggesting that PEPT1 is critical for the survival of cancer cells. We also establish that the tumor-derived lactic acid (Warburg effect) in the tumor microenvironment supports the transport function of PEPT1 in the maintenance of amino acid nutrition in cancer cells by inducing MMPs and DPPIV to generate peptide substrates for PEPT1 and by generating a H+ gradient across the plasma membrane to energize PEPT1. Taken collectively, these studies demonstrate a functional link between PEPT1 and extracellular protein breakdown in the tumor microenvironment as a key determinant of pancreatic cancer growth, thus identifying PEPT1 as a potential therapeutic target for PDAC.

204 Awardee Talk: Recent Advances in Protein Nutrition in Horses

Abstract Protein has been recognized as an essential nutrient for animals for well over 100 years. Protein plays many important structural and metabolic roles, and some of its component amino acids have additional functions, including as regulatory molecules, as energy substrates and in the synthesis of other non-protein molecules. Skeletal muscle makes up approximately 50% of body weight in horses, with protein being the major non-water component. As an athletic species, the development and maintenance of muscle mass is of the utmost importance in horses. Because muscle mass is largely determined by the balance of rates of muscle protein synthesis and breakdown, understanding how these pathways are regulated and influenced by dietary protein and amino acid provision is essential. Historically, much research regarding protein nutrition in horses has focused on the protein digestibility of different feed ingredients, and the adequacy of different protein sources in supporting the growth and maintenance of horses. This presentation will focus on some of the current areas of active research relating to protein nutrition in horses: the activation of the signaling pathways that regulate muscle protein synthesis, amino acid supplementation in athletic horses, protein metabolism in aged and horses and those with insulin dysregulation, and amino acid and protein nutrition in predominantly forage-fed horses. There are many exciting opportunities for future research in the area of protein and amino acid nutrition in horses across the lifespan.

Amino Acids Supplementation for the Milk and Milk Protein Production of Dairy Cows.

Simple SummaryThe composition of milk not only has nutritional implications, but is also directly related to the income of dairy producers. As regards milk’s composition, concerns around milk protein have emerged from the increased consumption of casein products. The synthesis of proteins in milk is a highly complex and high-cost process, because the conversion efficiency of dietary protein to milk protein is very low in dairy cows. Thus, some studies have increased milk protein by using protein supplements or a single amino acid (AA) supply. AAs are the building blocks of protein, and can also stimulate the protein synthetic pathway. This review mainly concerns the use of AAs for producing milk protein in high-producing dairy cows, particularly with methionine, lysine, and histidine. Understanding the mechanisms of AAs will help to promote milk protein synthesis in the dairy industry.As the preference of consumers for casein products has increased, the protein content of milk from dairy cows is drawing more attention. Protein synthesis in the milk of dairy cows requires a proper supply of dietary protein. High protein supplementation may help to produce more milk protein, but residues in feces and urine cause environmental pollution and increase production costs. As such, previous studies have focused on protein supplements and amino acid (AA) supply. This review concerns AA nutrition for enhancing milk protein in dairy cows, and mainly focuses on three AAs: methionine, lysine, and histidine. AA supplementation for promoting protein synthesis is related to the mammalian target of rapamycin (mTOR) complex and its downstream pathways. Each AA has different stimulating effects on the mTOR translation initiation pathway, and thus manifests different milk protein yields. This review will expand our understanding of AA nutrition and the involved pathways in relation to the synthesis of milk protein in dairy cows.

Hematological and biochemical indicators of rainbown trout blood depending on lysin and methionine levels in feed

The effect of use of complete feed with different lysine and methionine levels on the hematological and biochemical indicators of rainbow trout blood is studied in the article. The aim of the experiment was to establish the effect of different levels of amino acid nutrition of commercial rainbow trout on hematological and biochemical indicators of its blood. For this purpose, five experimental groups were formed by the analog method. The study lasted 210 days and was divided into two periods: equalizing (10 days) and basic (200 days). In the equalizing period, the trial fish consumed feed of the control group. In the basic period of the experiment, the level of lysine and methionine in the production feed ranged from 2.5 to 2.9% and from 0.8 to 1.0%, respectively. It was found that the different content of lysine and methionine in the diets of two-year-old rainbow trout did not cause significant changes in biochemical indicators of blood. The increase in the content of limiting amino acids in the combined feed of young rainbow trout caused slight deviations in hemoglobin content compared to control. The analysis of the obtained results revealed the highest content of erythrocytes (1.28 T/l) in the blood of specimen of experimental group 5, the level of amino acids in combined feeds was the lowest. Its highest content was found in the blood plasma of trout of experimental group 4, which received combined feed with a content of 2.8 % lysine and 0.95 % methionine. The concentration of total protein in the blood serum was almost the same in all experimental groups of commercial rainbow trout. It was found that different levels of amino acid nutrition of rainbow trout did not affect the dynamics of changes in the blood cell morphology differentials.

Interactive effects of dietary amino acid density and environmental temperature on growth performance and expression of selected amino acid transporters, water channels, and stress-related transcripts

Exposure to heat stress (HS) is one of the challenges facing the broiler industry worldwide. Various nutritional strategies have been suggested, such as altering dietary concentrations of some nutrients. Thus, we evaluated feeding different amino acid (AA) densities on live performance, Pectoralis (P.) muscles, and expression of selected AA transporters, water channels, and stress-related transcripts in a fast-growing broiler strain. Ross 308 chicks (n = 576) were randomly assigned to 4 dietary treatments (24 reps, 6 chicks per rep), differing in AA density (110, 100, 90, and 80% of a breeder's AA specifications). During 24 to 36 days of age, half of the birds were kept at a thermoneutral (TN) temperature of 20°C, whereas the other half were subjected to HS at 32° C for 8 h daily, making the treatment design a 4 × 2. The results revealed no interaction between housing temperature and AA density on growth performance or P. muscles weights. Feeding 80% AAs depressed BWG, FCR, and P. muscles at 36 d (P < 0.001). There was an interaction (P < 0.001) between AA density and temperature on the expression of all examined genes. Reducing the AA density beyond 100% upregulated the expression of AA transporter (CAT1, B0AT, b0,+AT, SNAT1, LAT1), HSP70, HSP90, glucocorticoid receptor (GR), and AQP3 in the TN birds’ jejunum. Whereas in the HS birds, inconsistent expressions were observed in the jejunum, of which CAT1, B0AT, and LAT1 were markedly downregulated as AA density was reduced. In P. major of TN birds, reducing AA density resulted in upregulating the expression of all AA transporters, HSP70, GR, and AQP1, while downregulating HSP90 and AQP9. In contrast, AA reduction markedly downregulated CAT1, B0AT, and LAT1 in the P. major of HS birds. These findings indicate that the dietary AA level alters the expression of various genes involved in AA uptake, protein folding, and water transport. The magnitude of alteration is also dependent on the housing temperature. Furthermore, the results highlight the importance of adequate AA nutrition for fast-growing chickens under HS.