Supply Of Essential Amino Acids Research Articles

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%.

Different dietary ratios of arginine, methionine and lysine for turkeys: effects on whole-body composition and nutrient utilization efficiency in the early growth stage

Abstract The growth rate, tissue development and health status of turkeys are affected by the dietary supply of essential amino acids (AAs) such as lysine (Lys), methionine (Met) and arginine (Arg). According to various guidelines, the diets fed to turkeys in the first 4 weeks of the rearing period should contain 1.60–1.76% Lys, 1.60–1.80% Arg and 0.55–0.70% Met. This study investigated the effects of different ratios of Arg and Met in starter diets with 1.60% of Lys content, i.e. a low level, on the whole-body composition of turkeys and nutrient retention efficiency. The experiment lasted for 28 days and it had a two-factorial randomized design with three levels of Arg (90%, 100% and 110%) and two levels of Met (30% or 45%), relative to the content of dietary Lys, with six groups of eight replicates per group and 18 turkeys per replicate. Different dietary Arg and Met levels, relative to Lys, did not affect AA concentrations in the body protein or the proximate whole-body composition (crude protein, crude fat, gross energy and ash) of turkeys. The higher Met level positively influenced energy, protein and Arg utilization and their retention efficiency as well as the growth performance of turkeys. An increase in the dietary level of Arg to 100% and 110% of Lys content had no influence on the growth performance of turkeys and it reduced the retention efficiency of Arg. Differences in the body weight gain, feed intake and Lys utilization of turkeys fed diets with different Arg levels resulted also from the strong interaction between Met and Arg levels. At the lower level of Met in the diet, a decrease in Arg relative to Lys from 100% to 90% resulted in decreased (P = 0.003) feed intake (from 50.34 g to 46.72 g) and growth rate (from 31.84 g to 29.79 g), which was not noted for the higher Met content (45% relative to Lys). At the lowest level of Arg in the diet (90% of Lys content), a decrease in Met relative to Lys from 45% to 30% caused a decrease in Lys retention efficiency (from 61.51% to 56.29%). The results of this study suggest that the higher content of Met in the diet (45% to Lys) and the Arg level corresponding to 90% of Lys content contribute to optimizing nutrient retention efficiency in turkeys during the first 28 days of their life.

Role of Essential Amino Acids in Age-Induced Bone Loss

Age-induced osteoporosis is a global problem. Essential amino acids (EAAs) work as an energy source and a molecular pathway modulator in bone, but their functions have not been systematically reviewed in aging bone. This study aimed to discuss the contribution of EAAs on aging bone from in vitro, in vivo, and human investigations. In aged people with osteoporosis, serum EAAs were detected changing up and down, without a well-established conclusion. The supply of EAAs in aged people either rescued or did not affect bone mineral density (BMD) and bone volume. In most signaling studies, EAAs were proven to increase bone mass. Lysine, threonine, methionine, tryptophan, and isoleucine can increase osteoblast proliferation, activation, and differentiation, and decrease osteoclast activity. Oxidized L-tryptophan promotes bone marrow stem cells (BMSCs) differentiating into osteoblasts. However, the oxidation product of tryptophan called kynurenine increases osteoclast activity, and enhances the differentiation of adipocytes from BMSCs. Taken together, in terms of bone minerals and volume, more views consider EAAs to have a positive effect on aging bone, but the function of EAAs in bone metabolism has not been fully demonstrated and more studies are needed in this area in the future.

Research of a Dry Extruded Mixture of Protein Rich Plant Composition

Abstract Since plant protein is generally accepted as sustainable and environmentally friendly, production of new plant protein-based products is expanding and a raw material is diversified to ensure a high-value and complete meal. The objective of the study was to compare chemical composition and amino acid provision of pea-buckwheat, pea-barley and pea-oat extruded mixtures with the aim to look for new products to diversify diet using the best plant protein resources. Within the research, amino acid scores of hull-less barley, buckwheat, hull-less oat and grey pea as an indicator of raw material protein quality were evaluated. The highest scores of essential amino acids were found in oat and pea protein. Amino acid scoring patterns of raw material – oat ‘Stendes Emilija’ and grey pea ‘Bruno’ fully meet the requirements for essential amino acid supply. The protein of buckwheat is the richest in lysine (4.3 g 100g−1 protein) among studied cereals, although the difference in the essential amino acids was not significant. The results of the research showed that pea-barley and pea-buckwheat composite mixtures meet human needs better if pea protein is used in the proportion 65:35 with barley or buckwheat flour than in the proportion 35:65. The high protein content – 43.33% and 43.96%, the sum and composition of essential amino acids, and high level of total dietary fibre – 11.9% and 13.7% are the main reasons to consider the mixtures (including as a base for smoothies) as a complete meal.

Enrichment of wheat flour with Spirulina. Evaluation of thermal damage to essential amino acids during bread preparation

Microalgae and cyanobacteria represent a sustainable and valuable source of essential amino acids and bio-active molecules (e.g. poly-unsaturated fatty acids and antioxidants) which, if added to staple food, could enrich its nutritional profile and the human diet. In this study, two different composite mixtures were obtained by adding different percentages (1% and 2%) of Spirulina powder to “Italian type 1” semi-whole wheat flour (W = 300) after which the chemical, physical, alveographic, and rheological parameters were subsequently analyzed.Spirulina powder did not cause drastic changes at the rheological level when added up to 2%. Furthermore, the concentration of proteins significantly increased in the samples enriched with 1% Spirulina (3.17%) and 2% Spirulina (5.12%), while at the same time the gluten content decreased by 5.62% and 7.41%, respectively. The total amount of essential amino acids in the samples enriched with 1% and 2% Spirulina (48,209 and 55,286 mgaa/kgDW, respectively), was higher in comparison with 45,433 mgaa/kgDW of the control, and those concentrations were maintained after the baking process. Spirulina powder confirmed the hypothesis of being able to improve the supply of essential amino acids that is lacking in wheat flour. The next steps include an investigation into the sensory and liking characteristics of the product.

Comparison of Experimental Strategies to Study l-Type Amino Acid Transporter 1 (LAT1) Utilization by Ligands.

l-Type amino acid transporter 1 (LAT1), expressed abundantly in the brain and placenta and overexpressed in several cancer cell types, has gained a lot of interest in drug research and development, as it can be utilized for brain-targeted drug delivery, as well as inhibiting the essential amino acid supply to cancer cells. The structure of LAT1 is today very well-known and the interactions of ligands at the binding site of LAT1 can be modeled and explained. However, less is known of LAT1′s life cycle within the cells. Moreover, the functionality of LAT1 can be measured by several different methods, which may vary between the laboratories and make the comparison of the results challenging. In the present study, the usefulness of indirect cis-inhibition methods and direct cellular uptake methods and their variations to interpret the interactions of LAT1-ligands were evaluated. Moreover, this study also highlights the importance of understanding the intracellular kinetics of LAT1-ligands, and how they can affect the regular function of LAT1 in critical tissues, such as the brain. Hence, it is discussed herein how the selected methodology influences the outcome and created knowledge of LAT1-utilizing compounds.

Assessment of vegan complete diets for dogs and cats available in Germany

Nutritional assessment of commercial vegan complete diets for adult cats and dogs and the evaluation of the products' legal labelling. Four complete vegan diets for adult cats and dogs available on the German market were analyzed concerning their nutrient and mineral content. The required amount of food was determined by calculation and compared to the manufacturers' feeding recommendation. Data labelling was assessed for its accordance with EC regulation 767/2009. The supply of taurine and vitamins was evaluated for its adequacy by use of the nutritional additive data on the product label. In most cases, the labelled data complied with the regulatory framework. The manufacturers' feeding recommendation differed significantly from the calculated feed quantity in 2 out of 4 feeds. The recommendations resulted in a coverage of 64 to 121 % of the total energy requirement, more frequently leading to an underestimation of the required feed amount. The supply of minerals exceeded the recommended allowance by 5.2- to 8.2-fold in the adult dog and by 9.0- and 11.4-fold in the adult cat. In 1 out of 4 diets, the European Pet Food Industry Federation guidelines were undercut for crude protein, crude fat and phosphorus. Zinc and copper contents were in excess and/or insufficient. A shortfall in National Research Council (NRC) recommendations was present for zinc content in one diet. Most products met the recommended supply of essential amino acids; 2 products only met the minimum requirements for methionine and cystine but not the recommended provision. The added taurine met the recommended intake in one commercial diet for cats. Requirements for vitamin intake were fulfilled by the nutritional additives in 3 products. None of the products fulfilled the energy and nutrient requirements for a complete diet for adult dogs and cats without limitations. Therefore, deficiencies in the supply of individual nutrients cannot be ruled out under long-term feeding of the examined vegan diets.

Etiology of Colitis-Complex Diarrhea in Growing Pigs: A Review

Simple SummaryDiarrhea in growing pigs is a challenge for the pig industry since it is associated with reduced animal welfare, retarded growth, increased feed conversion ratio, and is often treated with antibiotics. One of the major causes of diarrhea in the growing period is large intestinal inflammation, often referred to as colitis. The exact causes of colitis-complex diarrhea are still to be understood, but dietary factors and/or pathogens have been recognized as the major factors in developing colitis-complex diarrhea. In this review, a thorough picture of pathogens, dietary factors, and a number of possible biomarkers related to colitis-complex diarrhea is presented.Colitis-complex diarrhea (CCD) in pigs can be defined as a type of diarrhea, which is associated with colonic inflammation and disrupted colonic gut barrier functionality in growing pigs (4–16 weeks post-weaning). It is a challenge for the pig industry as it is associated with the high use of antibiotics, reduced animal welfare, and depressed growth rate. The exact etiology of CCD is still unclear; however, pathogens including Brachyspira (B.) hyodysenteriae, B. pilosicoli, and swine whipworms such as Trichuris (T.) suis have been involved in specific colitis (SC). In the absence of specific pathogens, dietary factors, such as high levels of protein, pelleted feedstuffs, and lack of sufficient antioxidants, can result in non-specific colitis (NSC). On the other hand, supplement of polyunsaturated fatty acids (PUFA) and polyphenols, sufficient supply of essential amino acids (e.g., threonine, cysteine, and proline), short-chain fatty acids (SCFA; especially butyrate), and resistant starch have shown to confer preventing/ameliorating effects on CCD. Different putative biomarkers associated with CCD have been presented. It is anticipated that a comprehensive picture of the possible causes of CCD and potential dietary interventions could cast light on the direction of future studies aimed at developing preventive and curative strategies against CCD in growing pigs.

Impact of lysine supplementation on growth and development ofHermetia illucens larvae

Hermetia illucens larvae are able to convert a broad range of organic substrates into animal protein and are believed to have the potential to help solving the supply problem for animal protein in the future. Many farmed animals such as poultry or pigs need an adequate amount of essential amino acids like lysine for optimal growth and performance. In most diets for farmed animals, essential amino acids are supplemented as feed additive to avoid excessive protein intake while ensuring a sufficient supply of essential amino acids. There is no information on the requirements of lysine for the growth ofH. illucens larvae. Furthermore, it remains open whether lysine may have an extra effect on growth and development in the cultivation of such larvae. The aim of the study was to evaluate, if an addition of lysine to their feed substrate will affect these parameters. Therefore, in the present study up to 3.0% crystalline lysine was added to a basic substrate and survival, growth, and development of larvae were recorded. Furthermore, larval nutritional values like crude fat, crude protein, and lysine content were analysed. The addition of lysine did not improve growth, development or nutritional values ofH. illucens larvae. In contrast, the addition of lysine led to reduced larval size, survival and prepupal rates, especially when high amounts of lysine were provided. The results of this study indicate that a lysine content of 0.3% in the substrate is sufficient for optimal larval growth. UsingH. illucens larvae for animal protein production could, therefore, be accomplished with less lysine compared to many other farmed animals.

Counter-directed leucine gradient promotes amino acid transfer across the human placenta

The developing fetus is highly vulnerable to imbalances in the supply of essential amino acids (AA). Transplacental AA transfer depends on complex interactions between accumulative transporters, exchangers and facilitators, which maintain both intra-extracellular and materno-fetal substrate gradients. We determined physiological AA gradients between maternal and fetal blood and assessed their importance by studying maternal-fetal leucine transfer in human trophoblasts. Maternal-venous and corresponding fetal-arterial/fetal-venous sera were collected from 22 healthy patients at partum. The acquisition of the full AA spectra in serum was performed by ion exchange chromatography. Physiological materno-fetal AA levels were evaluated using paired two-way ANOVA with Tukey's correction. AA concentrations and gradients were tested for associations with anthropometric data by Spearman correlation analysis. Functional effects of a physiological leucine gradient versus equimolar concentrations were tested in BeWo cells using L-[3H]-leucine in conventional and Transwell-based uptake and transfer experiments. The LAT1/SLC7A5-specific inhibitor JPH203 was used to evaluate LAT1-transporter-mediated leucine transport. Maternal AA concentrations correlated with preconceptional and maternal weights at partum. Interestingly, low materno-fetal AA gradients were associated with maternal weight, BMI and gestational weight gain. Leucine uptake was promoted by increased extracellular substrate concentrations. Materno-fetal leucine transfer was significantly increased against a 137µM leucine gradient demonstrating that transplacental leucine transport is stimulated by a counter-directed gradient. Moreover, leucine transfer was inhibited by 10µM JPH203 confirming that Leu transport across the trophoblast monolayer is LAT1-dependent. This study demonstrates a currently underestimated effect of transplacental AA gradients on efficient leucine transfer which could severely affect fetal development.

Management of Anaemia of Chronic Disease: Beyond Iron-Only Supplementation.

Chronic diseases are characterised by altered autophagy and protein metabolism disarrangement, resulting in sarcopenia, hypoalbuminemia and hypo-haemoglobinaemia. Hypo-haemoglobinaemia is linked to a worse prognosis independent of the target organ affected by the disease. Currently, the cornerstone of the therapy of anaemia is iron supplementation, with or without erythropoietin for the stimulation of haematopoiesis. However, treatment strategies should incorporate the promotion of the synthesis of heme, the principal constituent of haemoglobin (Hb) and of many other fundamental enzymes for human metabolism. Heme synthesis is controlled by a complex biochemical pathway. The limiting step of heme synthesis is D-amino-levulinic acid (D-ALA), whose availability and synthesis require glycine and succinil-coenzyme A (CoA) as precursor substrates. Consequently, the treatment of anaemia should not be based only on the sufficiency of iron but, also, on the availability of all precursor molecules fundamental for heme synthesis. Therefore, an adequate clinical therapeutic strategy should integrate a standard iron infusion and a supply of essential amino acids and vitamins involved in heme synthesis. We reported preliminary data in a select population of aged anaemic patients affected by congestive heart failure (CHF) and catabolic disarrangement, who, in addition to the standard iron therapy, were treated by reinforced therapeutic schedules also providing essential animo acids (AAs) and vitamins involved in the maintenance of heme. Notably, such individualised therapy resulted in a significantly faster increase in the blood concentration of haemoglobin after 30 days of treatment when compared to the nonsupplemented standard iron therapy.

Putative imbalanced amino acid metabolism in rainbow trout long term fed a plant-based diet as revealed by 1H-NMR metabolomics.

The long-term effect of a plant (P)-based diet was assessed by proton nuclear magnetic resonance (1H-NMR) metabolomics in rainbow trout fed a marine fish meal (FM)-fish oil (FO) diet (M), a P-based diet and a control commercial-like diet (C) starting with the first feeding. Growth performances were not heavily altered by long-term feeding on the P-based diet. An 1H-NMR metabolomic analysis of the feed revealed significantly different soluble chemical compound profiles between the diets. A set of soluble chemical compounds was found to be specific either to the P-based diet or to the M diet. Pterin, a biomarker of plant feedstuffs, was identified both in the P-based diet and in the plasma of fish fed the P-based diet. 1H-NMR metabolomic analysis on fish plasma and liver and muscle tissues at 6 and 48 h post feeding revealed significantly different profiles between the P-based diet and the M diet, while the C diet showed intermediate results. A higher amino acid content was found in the plasma of fish fed the P-based diet compared with the M diet after 48 h, suggesting either a delayed delivery of the amino acids or a lower amino acid utilisation in the P-based diet. This was associated with an accumulation of essential amino acids and the depletion of glutamine in the muscle, together with an accumulation of choline in the liver. Combined with an anticipated absorption of methionine and lysine supplemented in free form, the present results suggest an imbalanced essential amino acid supply for protein metabolism in the muscle and for specific functions of the liver.

Detection about fungal contamination in products milk in local and manufacturing yogurt and cheese in Al-Diwaniya city

This study included random examination of milk products such as yogurt and cheese in both types the local and manufacturing milk product, to detect the fungal contamination in these products. Yogurt was a well source of essential nutrients such as protein, essential minerals (Ca, P, Mg, Zn, K) and vitamins such as B1, B9, B2 B12, B3. Yogurt increase the body product of cytokine, activity of phagocytic cell, antibodies, T- cell and natural killer cell, also it induced immune system against other diseases such as cancer, gastrointestinal and allergic syndrome. Caseins are the main protein in cheese; which exist in the form of aggregates after combination with colloidal calcium phosphate common knowledge as micelles of casein. Caseins in cheese are nutritionally rich due to the high supply of essential amino acids, phosphate and calcium. Samples taken from market of al-Diwaniya city about ten samples for each type, these samples cultured on SDA by use dilution method and after incubated found several types of fungi were appeared, such as Candida albicans the general average for it cell in 1 ml about 2.7×10^2(cell/ml) in samples of local yogurt, 7.6×10 (cell/ml) in samples of manufacturing yogurt, in cheese; about 1.8×10(cell/ml) in samples of local cheese and 1.3×10 in manufacturing cheese. The fungi also appeared in samples such as Penicillium notatum, Aspergillus flavus, Fusarium oxysporium, Trichoderma harzianum, the higher frequency rate was recorded in samples of local yogurt about 13.7%, 25.4%, 19.6%, 11.3% respectively.

Effects of supplemented nonessential amino acids and nonprotein nitrogen on growth and nitrogen excretion characteristics of broiler chickens fed diets with very low crude protein concentrations

Reducing dietary CP for broiler chickens below a certain threshold results in decreased growth, even when the supply of essential amino acids and glycine equivalent (Glyequi) is adequate, probably because other nonessential amino acids (neAA) are growth-limiting. Nonprotein nitrogen (NPN) might be used for the synthesis of neAA. Therefore, the effects of specific neAA and ammonium chloride (NH4Cl) supplementation on the growth and N-excretion characteristics of broiler chickens were investigated. Nine male Ross 308 broiler chickens were kept in each of 81 metabolism units from day 7 to 21 and received 1 of 9 diets in 9 replicates in a one-factorial arrangement of treatments. Two diets with different neAA concentrations, except for Glyequi, were mixed resulting in CP levels of 180 (CP180) and 160 (CP160) g/kg. In six other diets, CP160 was supplemented with either l-Ala, l-Pro, l-Asp, a mix of l-Asp and l-Asn·H2O, l-Glu, or a mix of l-Glu and l-Gln to achieve concentrations of the respective neAA as formulated in CP180. In a further diet, NH4Cl was added to CP160 to achieve the CP concentration of CP180. The ADG and gain:feed ratio (G:F) from day 7 to 21 were highest at CP180. Reduced neAA concentrations in CP160 decreased ADG and G:F. Supplementation of Asp+Asn, Glu, and Glu+Gln to CP160 increased ADG and G:F, but not to the level found for CP180. Compared with CP160, addition of Asp increased G:F but not ADG. Supplementation of Asp+Asn caused higher ADG and G:F than supplementation of Asp alone. The N-utilization efficiency was highest at CP160 and at CP160 supplemented with Ala, Pro, and Glu. Lower N-utilization efficiency was found at CP180 than at CP160, without and with supplemented neAA. The treatment containing NH4Cl presented the lowest ADG, G:F, and N-utilization efficiency. These results showed that individual supplementation of Asp+Asn, Glu, and Glu+Gln partly compensates for the growth-reducing effects of very low CP diets. Supplementation of NH4Cl as NPN source is not suitable for broiler chickens.

Significant impact of casein hydrolysate to overcome the low consumption of glycerol by Klebsiella aerogenes ATCC 29007 and its application to bioethanol production

As the demand for biodiesel increases, the by-product glycerol is increasing. Biodiesel-derived glycerol is expected to be applied in bioindustries. However, major limitation of industrial fermentation is that the rate of substrate consumption is significantly slower than conventional process. In this study, in order to improve the consumption of refined crude glycerol in Klebsiella aerogenes, casein hydrolysate was supplemented in main medium. As a result, the substrate consumption rate, cell and ethanol concentration were improved about 2.6-fold, 2.5-fold and 3.0-fold, respectively, compared with the control group. In addition, four components of the main medium (peptone, ammonium sulfate, casein hydrolysate, refined crude glycerol) were statistically optimized. The consumption of glycerol was achieved about 89%, and the productivity of bioethanol was found to be 0.83 g/(L h) under the optimized medium. Also, the bioethanol concentration and yield were 15.89 g/L and 0.487 (g/g), respectively. The supplementation of casein hydrolysate had a significant effect on fermentation. It was proved by analyzing the concentration of free amino acids contained in casein hydrolysate. As a result, it was found that glycerol consumption and bioethanol production were promoted by the abundant supply of essential amino acids contained in casein hydrolysate for cell growth. Therefore, these results will be the basis for sustainable development by providing the opportunity to reuse crude glycerol for industrial applications.

Nutritional and Medical Perspectives of Whey Protein: A Historical Overview

Whey nowadays considered as nutritional power house of future. Presently, whey mainly used as energy base drinks for sportsman and for therapeutic application in many countries. The two primary sources of protein in milk are the caseins and whey. After processing occurs, the caseins are the proteins responsible for making curds, while whey remains in an aqueous environment. Whey protein is a reliable source of amino acids and biologically active proteins which act as a nutritional supplement. The components of whey include beta lactoglobulin, alpha lactoalbumin, bovine serum albumin, lactoferrin, immunoglobluins, lactoperoxidase enzymes, glycomacropeptides, lactose, and minerals. Whey proteins have a high amount of branched chain amino acids such as leucine, isoleucine, and valine. These are also rich in the sulfur-containing amino acids cysteine and methionine, which enhance immune functions through their intracellular conversion to glutathione. The present review paper gives information about the potential beneficial properties of whey protein and focuses on using whey protein supplementation as an immuno-modulator, antioxidant, anti-inflammatory, anti-diabetic, anti-cancer. In this context, the current review presented that whey protein supplementation is shown to maintain a high concentration of cellular antioxidants and boost immune defenses that promote carcinogen detoxification. Due to the positive findings, whey protein supplementation is starting to be viewed as a non-pharmaceutical adjunct therapy in the treatment of cancer. Also, whey protein provides an abundant supply of essential amino acids to organs and tissues, which stimulate tissue regenerative mechanisms and help minimize immune suppression.
 J Pharm Care 2019; 7(4): 112-117.

Host and symbiont genetic determinants of nutritional phenotype in a natural population of the pea aphid.

A defining feature of the nutritional ecology of plant sap-feeding insects is that the dietary deficit of essential amino acids (EAAs) in plant sap is supplemented by EAA-provisioning microbial symbionts in the insect. Here, we demonstrated substantial variation in the nutritional phenotype of 208 genotypes of the pea aphid Acyrthosiphon pisum collected from anatural population. Specifically, the genotypes varied in performance (larval growth rates) on four test diets lacking the EAAs arginine, histidine and methionine or aromatic EAAs (phenylalanine and tryptophan), relative to the diet containing all EAAs. These data indicate that EAA supply from the symbiotic bacteria Buchnera can meet total aphid nutritional demand for only a subset of the EAA/aphid genotype combinations. We then correlated single nucleotide polymorphisms (SNPs) identified in the aphid and Buchnera genomes by reduced genome sequencing against aphid performance for each EAA deletion diet. This yielded significant associations between performance on the histidine-free diet and Buchnera SNPs, including metabolism genes predicted to influence histidine biosynthesis. Aphid genetic correlates of performance were obtained for all four deletion diets, with associations on the arginine-free diet and aromatic-free diets dominated by genes functioning in the regulation of metabolic and cellular processes. The specific aphid genes associated with performance on different EAA deletion diets are largely nonoverlapping, indicating some independence in the regulatory circuits determining aphid phenotype for the different EAAs. This study demonstrates how variation in the phenotype of associations collected from natural populations can be applied to elucidate the genetic basis of ecologically important traits in systems intractable to traditional forward/reverse genetic techniques.

ДЕЙСТВИЕ УРОВНЯ БЕЛКА И ЕГО РАСПАДАЕМОСТИ НА ИСПОЛЬЗОВАНИЕ АЗОТА КОРМА, ОБЕСПЕЧЕННОСТЬ НЕЗАМЕНИМЫМИ АМИНОКИСЛОТАМИ И МОЛОЧНУЮ ПРОДУКТИВНОСТЬ ГОЛШТИНСКИХ КОРОВ-ПЕРВОТЕЛОК

ДЕЙСТВИЕ УРОВНЯ БЕЛКА И ЕГО РАСПАДАЕМОСТИ НА ИСПОЛЬЗОВАНИЕ АЗОТА КОРМА, ОБЕСПЕЧЕННОСТЬ НЕЗАМЕНИМЫМИ АМИНОКИСЛОТАМИ И МОЛОЧНУЮ ПРОДУКТИВНОСТЬ ГОЛШТИНСКИХ КОРОВ-ПЕРВОТЕЛОК

Seryl-tRNA synthetase-mediated essential amino acids regulate β-casein synthesis via cell proliferation and mammalian target of rapamycin (mTOR) signaling pathway in bovine mammary epithelial cells

Essential amino acids (EAA) play an important role in promoting milk protein synthesis in primary bovine mammary epithelial cells (BMEC). However, the regulatory mechanisms involved in the relationship between EAA and milk protein synthesis have not been fully explored. This study examined the effects of seryl-tRNA synthetase (SARS) on EAA-stimulated β-casein synthesis, cell proliferation, and the mammalian target of rapamycin (mTOR) system in BMEC. First, BMEC were cultured in medium either lacking all EAA (-EAA) or that included all EAA (+EAA) for 12 h. The BMEC were then supplemented with the opposing treatments (-EAA supplemented with +EAA and vice versa) for 0 h, 10 min, 0.5 h, 1 h, 6 h, or 12 h, respectively. After the treatment-specific time allotment, proteins were collected for Western blotting. Subsequently, a 2 × 2 factorial design was used to evaluate the interactive of SARS inhibition (control or SARS inhibited) and EAA supply (+EAA or -EAA) on gene and protein abundance, cell viability, and cell cycle in BMEC. Based on the data obtained in the first experiment, the changes in protein abundance of β-casein and SARS depended on EAA treatment time in similar patterns. The protein abundance of β-casein, SARS, and mammalian target of rapamycin (mTOR)-related proteins, cell viability, cell cycle progression, and the mRNA abundance of cyclin D1 (CCND1, cell cycle progression marker) and marker of proliferation Ki-67 (MKI67, cell proliferation marker) were stimulated by the presence of EAA. Correspondingly, when cells were deprived of EAA, cell proliferation and abundance of these proteins and genes were reduced overall. Moreover, the decreases in these aspects were further exacerbated by inhibiting SARS, suggesting that an interaction between EAA and SARS is important for regulating protein synthesis. The results indicated that SARS stimulated the mTOR signaling pathway when EAA were present, enhanced EAA-stimulated cell proliferation, and contributed to increased β-casein production in BMEC.

Macronutrient and amino acids composition of milk replacers for dairy calves

SUMMARY Other than crude protein (CP), crude energy (CE) and crude fiber (CF) content, the adequate supply of essential amino acids (EAA) is an important factor in milk replacer evaluation. The aim of this study was to analyze milk replacer samples as regard to nutrients, especially EAA, composition and simulate the attainability of calves' requirements in different feeding systems. Forty-one milk replacer samples were collected from 14 brands and analyzed for nutrient composition. The near infrared spectroscopy technique was used for AA content estimation. Samples presented adequate levels of CP (21.2±2.90%) and ether extract (14.5±3.41%) for calves fed according to the conventional (4L/d), but not for intensive milk feeding system (>6L/d). High values of CF were observed in the samples (1.6±0.86%). The EAA composition of milk replacer samples was lower than expected for a liquid feed supposed to replace whole milk. None of the analyzed samples presented adequate lysine (5.72±1.09% CP) or methionine (1.65±0.38% CP) to meet calves' daily requirements, regardless of feeding system. Higher crude protein milk replacers are needed. Alternatively, supplementation of milk replacers with EAA is recommended.