Total Essential Amino Acid Concentrations Research Articles

Enhancing the Nutritional Profile of Noodles With Bambara Groundnut (Vigna subterranea) and Moringa (Moringa oleifera): A Food System Approach

Bambara groundnut (BG, Vigna subterranea) and moringa (Moringa oleifera) are underutilised crops that improve nutritional quality of diets locally. The objectives of this study were to measure the performance of both crops on a marginal soil, analyse the harvested plant parts and noodles produced from them, and to undertake taste testing and survey consumer reactions. The noodles contained either 100% wheat flour or wheat with either BG flour (20%) or moringa powder (6%). BG yielded 0.70 t ha-1 of dry nuts and moringa 1.54 t ha-1 of dry leaflets. Both plant products were high in nutrients (especially K, and Ca in moringa) and some amino acids. Inclusion in noodles significantly enhanced their nutritional composition particularly energy content, crude fat, crude fibre and carbohydrate. Significant increases (p<0.05) of Mg, Mn, P, K and Zn occurred. Total essential amino acid concentration increased from 34.1% in the pure wheat noodles to 38.2% in BG and 34.8% in moringa noodles. Sensory analysis showed acceptability of all three noodle types was above the “Neither like nor dislike” category leaning towards the liking end for almost all the attributes tested. A consumer reaction survey showed there were internal and external factors motivating respondents to choose both products. Weak correlations were found between some of these factors and respondents’ willingness to pay more for the BG and moringa noodles. We conclude that adopting a comprehensive research approach from plant to plate can assist transfer of underutilised crops from field studies to acceptable consumer products with enhanced nutritional profiles.

Effect of N-acetyl-l-methionine supplementation on lactation performance and plasma variables in mid-lactating dairy cows

The objective of current study was to investigate the effect of N-acetyl-l-methionine (NALM) supplementation on lactation performance and plasma variables in mid-lactating dairy cows. Forty-eight multiparous cows were blocked into 12 groups based on parity, days in milk, and milk production and were randomly assigned to 1 of the 4 treatments: 0, 15, 30, or 60 g/d of NALM per cow to supplement the basal diet. The experiment was conducted over a 13-wk period, with the first week as adaptation. The yields of milk, fat-corrected milk, and milk lactose were increased quadratically, and energy-corrected milk yield tended to increase with increased NALM supplementation in a quadratic manner. The dry matter intake, milk protein yield, milk fat yield, contents of milk composition (protein, fat, lactose, total solids, and milk urea nitrogen), feed efficiency, and body weight change were not affected by NALM supplementation. In addition, plasma methionine concentration was increased quadratically, and proline, total nonessential AA, and total AA concentrations were significantly higher in the 30 g/d group compared with that of the control group. However, other AA and total essential AA concentrations were not affected with supplementation of NALM. Adding NALM increased concentrations of total protein and globulin in plasma, but decreased plasma urea nitrogen concentration in a quadratic manner. Meanwhile, plasma malonaldehyde concentration decreased linearly as doses of NALM addition increased. Our results suggested that the supplementation of NALM improved milk yield and protein synthesis in the liver, and lowered lipid peroxidation in mid-lactating dairy cows.

Effects of dietary glutamate supplementation on flesh quality, antioxidant defense and gene expression related to lipid metabolism and myogenic regulation in Jian carp (Cyprinus carpio var. Jian)

The present study was conducted to investigate the effects of dietary glutamate (Glu) supplementation on flesh quality, antioxidant defense and gene expression related to lipid metabolism and myogenic regulation. A total of 600 Jian carp Cyprinus carpio var. Jian with the similar size (mean initial weight 126.40 ± 0.21 g) were randomly assigned to five dietary treatment groups for feeding 63 days: a basal diet, basal diet supplemented with 4, 8, 16, and 32 g kg−1 Glu. With Glu supplement, the relative shear force, hydroxyproline content, and pH value have been significantly increased, and cooking loss and lactate content have been significantly decreased in muscle. Muscle protein, lipid, and the total essential amino acid concentration were significantly improved by Glu. Meanwhile, dietary Glu supplementation also modified muscle fatty acid profiles. Additionally, Glu supplementation significantly enhanced GSH content and the activities and gene expression of CuZnSOD, GPx, GST, and GR in muscle. The enhanced antioxidant enzymes activities were modulated by Nrf2. The expression level of genes involved in myogenic regulation (MyoD, Myf5, myogenin, and Mrf4) and TOR were significantly elevated by dietary Glu supplementation. Moreover, dietary Glu supplementation increased FAS mRNA level and decreased LPL mRNA level. In conclusion, these results suggest that Glu is a potential role to improve muscle flesh quality and the underlying mechanism may be partly due to regulate lipid metabolism, myogenic regulatory factors, and antioxidative capacity induced by Glu.

Exercise Training in Standardbred Horses Alters the Skeletal Muscle Metabolome and Plasma Amino Acid Profile: Implications for the “Athlete's Paradox”

To date equine skeletal muscle metabolism has centered on a limited number of candidate metabolites. As such, there is a dearth of information regarding global changes in skeletal muscle metabolism following exercise training. Thus, the purpose of this study was to determine the effects of exercise training on skeletal muscle metabolism through changes in the skeletal muscle metabolome in healthy, untrained Standardbred horses. In addition, we aimed to determine the extent to which protein metabolism is also altered through changes in the concentrations of plasma amino acids (AA). We hypothesized that training would significantly alter the skeletal muscle metabolome, as well as protein metabolism, as reflected in changes in the plasma AA profile. Eight untrained, Standardbred horses (n=4 mares, n=4 geldings; 3–9 yrs; 485 ± 13 kg, mean ± S.E.) underwent a 12‐week training program that significantly increased VO2 and exercise capacity (p&lt;0.05). Percutaneous needle biopsies were obtained from the M. gluteus medius in the untrained state (UT) and again following training (TR). Frozen muscle samples were submitted to Metabolon, Inc. for global metabolite profiling via UHPLC‐MS/MS. Blood obtained via jugular venipuncture was placed into EDTA tubes for the measurement of plasma AA concentrations via HPLC. For metabolomics analysis, differences between UT and TR samples were evaluated by two way‐ANOVA and Welch's t‐test for paired comparisons and considered significant at p&lt;0.05. For plasma AAs, differences were analyzed via Student's t‐test and considered significant at p&lt;0.05. Training resulted in significant alterations in lipid, branched‐chain amino acid (BCAA), and nucleotide metabolite classes in skeletal muscle. Of note, analysis revealed significant increases in the relative abundance of almost every identified FFA and complex lipid species in TR compared to UT muscle (p&lt;0.05), particularly the long‐chain (LC)‐acylcarnitines and diacylglycerides (DAGs) (1.5 to 2.3‐fold increases). Further, TR muscle exhibited increased fold‐changes (1.2 to 4.2‐fold) of C4 and several C5 BCAA‐derived acylcarnitines compared to UT (p&lt;0.05). In plasma, training caused a significant 36% increase in the concentration of total essential AAs (p&lt;0.05), of which and interestingly there was a significant increase in total BCAAs (42%, p&lt;0.05) and phenylalanine (27%, p&lt;0.05). In conclusion, exercise training significantly increased blood concentrations of total EAAs and BCAAs alongside significant increases in the relative abundances of certain skeletal muscle metabolites (i.e. LC‐acylcarnitines, BCAA‐derived acylcarnitines, and DAGs) that have been shown to be elevated during obesity and are proposed to play a role in the development of insulin resistance. These data underscore the complex nature of static metabolic signatures and the role that certain metabolites play in mediating health and disease. Future research should aim to utilize other sophisticated techniques that can address issues of metabolite flux and tissue utilization.Support or Funding InformationThis research was supported by: the New Jersey Institute for Food, Nutrition and Health (IFNH), USDA NIFA (NC 1184), the Rutgers University Equine Science Center (ESC), and the New Jersey Agriculture Experiment Station (NJAES).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Lowering rumen-degradable and rumen-undegradable protein improved amino acid metabolism and energy utilization in lactating dairy cows exposed to heat stress

The objective of this study was to evaluate the effects of reducing dietary rumen-degradable protein (RDP) and rumen-undegradable protein (RUP) on protein and energy metabolism in heat-stressed dairy cows. Eighteen primiparous and 30 multiparous mid-lactation Holstein cows were used in a completely randomized design arranged in a 2 × 2 factorial (n = 12/treatment). Cows were randomly assigned to 1 of 4 dietary treatments that included 2 levels of RDP (10 and 8%; D) and 2 levels of RUP (8 and 6%; U) of dry matter for 21 d as (1) 10D:8U, (2) 8D:8U, (3) 10D:6U, and (4) 8D:6U. Diets were isoenergetic and contained 50% forage and 50% concentrate (dry matter basis). Cows were housed in a freestall barn. Three weeks before start of treatments, all animals were fed the 10D:8U diet and received supplemental cooling to prevent heat stress. During the treatment period, cows experienced a daily increment in temperature-humidity index from 74 to 82 for 1000 to 2000 h. Blood samples were collected on d -1 and 21 of the treatment period to determine plasma concentrations of AA, glucose, insulin, fatty acids, and β-hydroxybutyrate. For primiparous cows, reducing from 10 to 8% RDP decreased insulin concentrations. For multiparous cows, we found significant RDP by RUP interactions for insulin, β-hydroxybutyrate, fatty acids, total essential AA, and 3-methylhistidine concentrations. Reducing from 10 to 8% RDP decreased insulin concentrations at 6% RUP, but concentrations did not change when reducing RDP at 8% RUP. Reducing from 10 to 8% RDP decreased β-hydroxybutyrate concentrations at 8% RUP, but concentrations did not change when reducing RDP at 6% RUP. Reducing from 10 to 8% RDP increased nonesterified fatty acid and total essential AA concentrations at 8% RUP, but concentrations did not change when reducing RDP at 6% RUP. Reducing from 8 to 6% RUP decreased 3-methylhistidine concentration at 8% RDP, but not at 10% RDP. Reducing from 8 to 6% RUP increased milk protein yield efficiency in primiparous and multiparous cows. These results indicate that reducing RDP and RUP lowers circulating insulin, which was associated with mobilization and utilization of fatty acids. Reduced RDP and RUP increases the use of AA to maintain milk protein synthesis and limit AA catabolism in cows exposed to warm climates.

Profiles of serum amino acids to screen for catabolic and inflammation status in calves with Mycoplasma bronchopneumonia.

The aim of the present study was to investigate the relationships between serum amino acid profiles in normal and calves with Mycoplasma bronchopneumonia. Serum free amino acid concentrations in serum obtained from 34 calves with or without Mycoplasma bronchopneumonia were determined by high-performance liquid chromatography. The calves with Mycoplasma were characterized by significantly lower total amino acid and total essential amino acid concentrations and molar ratios of branched-chain amino acid (BCAA) to aromatic amino acid (BCAA/AAA) and BCAA to tyrosine (BTR), and by a significantly higher molar ratio of serine phosphorylation (SPR). The proposed diagnostic cutoffs for BCAA/AAA, BTR and SPR in serum based on ROC analysis for detection of catabolic states associated with Mycoplasma bronchopneumonia were set at <1.75, <2.86 and >0.85, respectively. Our results suggest that determining the profiles of amino acids, especially BTR and SPR, could provide useful diagnostic information in terms of predicting protein catabolism in Mycoplasma bronchopneumonia.

Increased consumption of salmon during pregnancy partly prevents the decline of some plasma essential amino acid concentrations in pregnant women

Oily fish is a good source of n-3 long-chain polyunsaturated fatty acids. Since these fatty acids may change efficiency of amino acid (AA) absorption, we determined whether increased salmon consumption influences plasma AA concentrations in pregnant women and their newborns. Pregnant women were randomly allocated to remain on their habitual diet (n = 61; control group) or to consume two 150 g farmed salmon portions per week from 20 weeks pregnancy until birth (n = 62; salmon group). Plasma AA concentrations were determined in women at w20, w34 and w38 of pregnancy and in umbilical cord at delivery. Concentrations of arginine, valine, leucine and lysine were affected by both time of pregnancy and salmon intake (p < 0.05), with a smaller gestation-associated decrease in the salmon group. Total essential AA concentrations were similar in both groups at w20, but at w38 were higher in salmon group (p < 0.05). Cord plasma AA concentrations, higher than in maternal plasma (p < 0.01), were similar in the two groups (p > 0.05). Two portions/wk of oily fish increased plasma essential AA concentrations during pregnancy and could contribute to a maternal health benefit. Two portions/wk of salmon did not affect plasma AA concentrations in the newborn. NCT00801502.

Food Value and Phytochemical Composition of &lt;i&gt;Luffa &lt;/i&gt;&lt;i&gt;c&lt;/i&gt;&lt;i&gt;ylindrica&lt;/i&gt; Seed Flour

<b> </b>Amino acid, fatty acid and phytochemical compositions of <i>Luffa cylindrica</i> seed flour were investigated. The total amino acid concentration was 72.71g/100g protein and the total essential amino acid concentration was 38.76g/100g protein. Arginine (9.75g/100g protein) was the most concentrated essential amino acid while the Lysine/Arginine ratio was 0.52. The calculated isoelctric point (pI), predicted protein efficiency ratio (P-PER) and limiting amino acid were 5.91, 1.89 and threonine respectively. Linoleic acid (31.47%) was the most abundant fatty acid in the seed flour. Unsaturated fatty acids (66.9%) were of higher concentration than saturated fatty acids (33.07%) while the total concentration of polyunsaturated fatty acids was 52.02%. Flavonoids (4.53%) were the most concentrated phytochemical in the <i>Luffa cylindrica</i> seed flour while saponins, alkaloids and cardiac glycosides were also present. This study shows that <i>Luffa cylindrica</i> seed contains a high proportion of essential amino acids and has a low atherogenic potential. Also, it is a potential source of healthy fat that may be useful as source of food nutrient and phytomedicine.

Validation of an in vitro digestive system for studying macronutrient decomposition in humans

In vitro digestion systems have proven to be powerful tools for understanding and monitoring the complex transformation processes that take place during digestion. In this study, human digestion was simulated with a three‐step in vitro process that was validated in depth by choosing pasteurized milk as an example of a complex food matrix. The decomposition of the macronutrients was followed over the entire digestive process to the level of intestinal enterocyte action, using protein and peptide analysis by SDS‐PAGE, reversed phase HPLC, size exclusion HPLC, and LC‐MS. The mean peptide size after in vitro digestion of pasteurized milk was 5–6 amino acids. Interestingly, mostly essential amino acids (93.6%) were released during in vitro milk digestion, a significantly different relative distribution compared to the total essential amino acid concentration of bovine milk (44.5%). All triglycerides were degraded to free fatty acids and monoacylglycerols. Herein, we present a human in vitro digestion model validated for its ability to degrade the macronutrients of dairy products comparable to physiological ranges.This project is financially supported by the Swiss federal program NanoTera.Grant Funding Source: Swiss Ferderal Research Program NanoTera

Early Changes in Plasma Amino Acid Concentrations during Aggressive Nutritional Therapy in Extremely Low Birth Weight Infants

To examine the changes in plasma amino acid (AA) concentrations over time when extremely low birth weight infants are provided either a standard intravenous AA supplementation (standard AA) or an early and high supplementation regimen (early and high AA). Sixty-two infants were enrolled at birth in a randomized, double-masked, prospective fashion and treated for 7 days. The infants with standard AA concentrations received intravenous AA starting at 0.5 g/kg/d and increased by 0.5 g/kg every day to a maximum of 3 g/kg/d. Infants in the early and high AA group received 2 g/kg/d of intravenous AA soon after birth and advanced by 1 g/kg every day to 4 g/kg/d. Plasma AA concentrations were determined by high-pressure liquid chromatography on days 1, 3, and 7. Total AA concentrations, total essential AA concentrations, and total nonessential AA concentrations were significantly higher in the infants in the early and high AA group; essential AA concentrations and total AA concentrations were higher at 1 and 3 days, and nonessential AA concentrations were different only on day 3. There were significant differences between standard AA and early and high AA groups for all AA concentrations except the nonessential AAs Glu, Asn, Gly, Gln, Ala, and Tyr and the conditionally essential AA Cys. Infants who received early and higher parenteral AA had higher plasma AA concentrations.

Effects of rumen-protected tryptophan on growth performance, fibre characteristics, nutrient utilization and plasma essential amino acids in Cashmere goats during the cashmere slow growth period

Tryptophan (Trp) is a limiting amino acid in growing ruminants and supplementation of Trp in a rumen-protected form may have positive effects on performance in ruminants. Trp may affect cashmere fibre growth by regulating plasma melatonin secretion. From December to February, identified as the cashmere slow growth period, cashmere growth rate slows down and plasma melatonin secretion declines. Thus, Trp supplementation may affect cashmere fibre growth positively during this period. This study was conducted to investigate the effects of rumen-protected tryptophan (RPT) on Cashmere goats during the cashmere slow growth period. Optimal RPT supplementation level was determined. The Thirty-six Liaoning Cashmere goat wethers (41.63 ± 0.37 kg) aged 1.5-year-old were stratified by weight and randomly assigned to the following treatments: without RPT (control), low RPT (LRPT), medium RPT (MRPT) and high RPT (HRPT) at RPT levels of 0, 2.0, 4.0 and 6.0 g per goat per day, respectively. LRPT and MRPT supplementation increased average daily gain ( P < 0.05) and N retention ( P < 0.05).The length and growth rate of cashmere fibre increased both linearly ( P < 0.05) and quadratically ( P < 0.05) with increasing RPT supplementation. Plasma Trp concentration increased linearly ( P < 0.05) with increasing RPT supplementation. Conversely, RPT supplementation decreased plasma isoleucine, valine and total essential amino acid concentrations ( P < 0.05). In conclusion, RPT supplementation potentially enhanced growth performance, cashmere fibre growth and N utilization in Liaoning Cashmere goat wethers. In experimental conditions of the current trial, the optimum RPT supplementation level was 2.0 g per goat per day during the cashmere slow growth period.

The effect of rumen degradable protein level and source on the duodenal essential amino acid profile of sheep

Two trials were conducted to determine the effects of rumen degradable protein (RDP) level and source on the duodenal essential amino acid (AA) composition of Dohne Merino wethers. The animals had ad libitum access to wheat straw (32 g crude protein (CP)/kg DM; 742 g neutral detergent fibre (NDF)/kg DM) and water. In the first experimental treatments casein provided 0, 40, 80, 120 and 160 g supplemental RDP/d. In experiment two, urea-nitrogen replaced 0, 25, 50, 75 and 100% of the true protein in the isonitrogenous treatments. Expressing essential AA concentration as a percentage of duodenal protein indicated that increasing RDP levels tended to decrease arginine, but significantly increased tryptophan concentrations. Histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, valine and total essential AA concentrations were not affected by dietary RDP level. Increasing the urea-N content of RDP supplements significantly decreased isoleucine, leucine, lysine, phenylalanine, tryptophan, valine and total essential amino acid (TEAA) concentrations. Histidine and threonine proportions also tended to decrease with higher non-protein N levels. When the essential AA profile is expressed in relation to lysine, the concentrations of histidine, leucine, phenylalanine and threonine decreased significantly. Arginine and valine showed a decreasing trend and tryptophan increased significantly as RDP levels were raised. The largest differences appeared between 0 and 40 g RDP supplementation, while the AA patterns for the rest of the treatments remained relatively constant. Substituting urea for true RDP induced a variable response in arginine and isoleucine, but did not affect any of the other AA\'s. Increasing RDP intakes significantly increased the duodenal flow of every essential AA, except arginine, and showed a strong tendency to increase TEAA flow as well. Replacing true RDP with urea significantly reduced the flow of methionine and tryptophan and also tended to decrease lysine availability in the duodenum. Individual AA and TEAA flow to the duodenum were also numerically decreased by a minimum of 34% as urea-N was increased. It appears that the qualitative duodenal essential AA profile in sheep fed low quality forages is relatively insensitive to RDP level or source. The daily essential AA flow to the duodenum seems to be compromised by urea substitution for true RDP.. Keywords : Amino acid; microbial protein;rumen degradable protein; urea; casein South African Journal of Animal Sciences Vol. 35 (3) 2005: pp.162-171

Amino acid composition of Arctic charr, Salvelinus alpinus (L.) and the prediction of dietary requirements for essential amino acids

Embryo somatic tissues, non-somatic yolk-sac materials, and whole, individual fingerlings (age 0+) of Arctic charr, Salvelinus alpinus (L.), as well as a commercial trout diet, were analysed for a wide spectrum of amino acids. Analytical material consisted of prefeeding swim-up fry that were separated into discrete yolk sac and somatic embryo tissue samples. Amino acid concentrations in fry somatic tissue and whole fingerlings were generally very similar to each other, but were lower than those measured in yolk materials. Higher correlations were observed between the majority of specific amino acid concentrations in the trout diet when compared with fingerling data (r2 = 0.91) and fry somatic tissue data (r2 = 0.89), than when correlated with fry yolk sac material (r2 = 0.76). These results indicate that the essential amino acid profiles of fry somatic tissue and whole fingerlings are closer to that of a commercial feed than they are to the endogenous profiles found in the embryonic yolk sac material itself. The dietary ratios of individual essential amino acids were also compared with the total essential amino acid concentrations (A/E ratios) in whole fingerling tissues, and these ratios could be used to accurately estimate the apparent essential amino acid requirements of Arctic charr. The rationale for using carcass amino acid composition data to estimate the dietary essential amino acid requirements of Arctic charr is discussed.

Effect of Postruminal Glutamine Supplementation on Immune Response and Milk Production in Dairy Cows

Seventeen multiparous Holstein cows were used to examine the effect of an increased duodenal supply of Gln on immune function and production. Cows received continuous abomasal infusions of water (control: n = 8) or 300g/d of Gln (n = 9) for 21 d starting within 48h of calving. There were nonsignificant increases in milk and milk protein yields in response to Gln supplementation. Glutamine treatment had no effect on plasma glucose, nonesterified fatty acids (NEFA), or β-hydroxybutyrate (BHBA) concentrations but did tend to increase plasma urea N concentration. The Gln treatment resulted in an increase of 108μM in the plasma Gln concentration. Total essential AA concentrations decreased with the Gln treatment, whereas total nonessential AA concentrations were unaffected. T Lymphocyte proliferation did not differ between the control and Gln-treated cows. Treatment had no effect on the relative abundance of CD8 T cells but did increase the abundance of CD4 T cells. Cytokine production, as measured by IFN-γ concentration determined in vitro in concanavalin-A-stimulated peripheral blood mononuclear cells, was similar between the treatments. Over the first 3 wk following calving, Gln supplementation had limited effects on milk production, metabolic parameters, and immune function.

A 3-MONTH STUDY of LBW INFANTS FED PARTIALLY or EXTENSIVELY HYDROLYSED PRETERM FORMULAS: GROWTH PARAMETERS, INDICES OF PROTEIN METABOLISM, PLASMA AMINO ACID CONCENTRATIONS

36 Background: Two previous studies have reported data on plasma amino acid concentrations in infants fed preterm hydrolysed formulas. The use of a high percentage of whey resulted in an increase in plasma threonine and a significant decrease in valine, leucine, tyrosine, phenylalanine and histidine [Acta Pediatr Suppl 405:98-104,1994]. The use of acidic whey reduced hyperthreoninemia and lead to plasma amino acid concentrations close to reference value [JPGN 24:491,1997]. These studies were short-term (analysis were performed at the end of first month) and only one type of hydrolysed preterm formulas was analysed. Aim: The aim of this study was to evaluate the effect of feeding both extensively and partially hydrolysed preterm formulas compared to standard preterm formula and fortified breast milk on growth, indices of protein metabolism (including plasma amino acid concentrations) followed during the first 3 months of life. Methods: Sixty low-birth-weight infants (birth weight 1535±104.2 g), appropriate for gestational age were enrolled into the study. The infants were randomly assigned to receive one of three study formulas: extensively hydrolysed (EH, n=15), partially hydrolysed (PH, n=15) preterm formula, standard preterm formula (SF, n=15) or fortified breast milk (FBM, n=15). The infants were investigated at the ages of 4, 8 and 12 weeks. Physical examination included anthropometric measurements (weight, length, and head circumference). On the day of examination samples of venous blood were obtained following 2-3 hour fast. Serum urea, albumin, prealbumin, transferrin and plasma amino acid concentrations were measured. Overall significance of a group difference was determined by ANOVA for repeated measurements. For the analysis of group differences multiple comparisons procedures (LSD, Duncan) were applied. Results: Weight gain was significantly higher in groups fed PH and SF when compared to the group fed FBM at 8 and 12 weeks. There were no differences with respect to length and head circumference among the groups throughout the study. Serum urea was significantly higher in groups fed EH, PH and SF than in FBM at 12 weeks. Plasma concentrations of albumin, prealbumin and transferrin did not differ throughout the study. Plasma concentrations of total amino acid and total essential amino acid concentrations did not differ. Significant differences were found in plasma concentrations of tyrosine, valine and glutamine. Tyrosine was significantly higher at 4 weeks in groups fed EH and PH than in FBM and at 12 weeks in group PH than in groups fed FBF and EH. Valine was significantly higher in groups fed PH and SF than in group fed FBM at 8 and 12 weeks. Glutamine was significantly higher in groups fed PH and SF than FBM at 8 weeks. Conclusions: In this three-month study of preterm infants fed extensively and partially hydrolysed preterm formula no significant differences were found in growth, indices of protein metabolism and plasma amino acid concentrations as compared with standard preterm formula. Although some significant differences were found in weight gain, urea concentrations and plasma concentrations of some amino acids between preterm infants fed both partially and extensively hydrolysed formulas and those fed fortified human milk, all the parameters were within reference values. These results are indicative of a satisfactory biochemical tolerance of extensively and partially hydrolysed preterm formulas.

A new approach to genetic alteration of soybean protein composition and quality

AbstractAlthough soybeans produce high‐quality meal, modern animal and fish production systems often require synthetic essential amino acid supplements to fortify feed rations. However, biotechnology may enable development of soybeans with naturally adequate levels of certain essential amino acids for advanced feed formulations. One approach involves genetic manipulation of glycinin (11S) and β‐conglycinin (7S) contents, the principal components of soybean storage proteins. Because 11S contains more cysteine and methionine than 7S protein, a higher 11S:7S ratio could lead to beneficial changes in the nutritional quality of soybean meal. Although genotypic variation for 11S:7S may be low among soybean [Glycine max (L.) Merr.] germplasm, ratios ranging from 1.7–4.9 were observed among accessions of the wild ancestor of cultivated soybean (Glycine soja Sieb, and Zucc.). Thus, wild soybean germplasm was evaluated as a potential source of genes that govern protein synthesis that may have been lost during the domestication of G. max. Change in the amount of 11S protein accounts for a significant portion of the genotypic variation in protein concentration and composition among wild soybeans. Strong positive correlation exists between the 11S:7S ratio and methionine or cysteine concentration of total protein. Moderate positive associations were found for threonine or tyrosine. A moderate negative correlation was found between lysine and 11S:7S. No association was found for leucine and phenylalanine or for total essential amino acid concentration. Based on these data, G. soja may contain a different complement of genes that influence expression of 11S and 7S proteins than G. max germplasm. Thus, through interspecific hybridization, wild soybeans may be a useful genetic resource for the further improvement of protein quality in cultivated soybeans.

Immediate commencement of amino acid supplementation in preterm infants: Effect on serum amino acid concentrations and protein kinetics on the first day of life

To determine whether the general reluctance to begin amino acid administration to preterm infants from birth onward might lead to loss of lean body mass and impairment of growth, we measured amino acid levels and protein kinetics in 18 preterm infants. Nine infants received amino acids (1.15 ± 0.06 gm · kg -1 · day -1) and glucose (6.05 ± 1.58 gm · kg -1 · day -1), whereas the other nine infants received only glucose (6.48 ± 1.30 gm · kg -1 · day -1) from birth onward. Protein kinetics on the first postnatal day were measured with a stable isotope dilution technique with [1- 13C]leucine as a tracer. No statistically significant differences were noted in blood pH, base excess, urea concentration, or glucose levels. Both total amino acid concentration and total essential amino acid concentration were significantly lower and were below the reference range in the nonsupplemented group. Plasma amino acid levels of five essential amino acids (methio-nine, cystine, isoleucine, leucine, arginine) were below the reference range in the nonsupplemented group, whereas only cystine was below the reference range in the supplemented group. Nitrogen retention was improved significantly by the administration of amino acids (-110 ± 44 mg nitrogen per kilogram per day in the glucose-only group vs +10 ± 127 mg nitrogen per kilogram per day in the group given glucose and amino acids; p = 0.001); leucine oxidation was not significantly increased in the supplemented group (41 ± 13 μmol · kg -1 · hr -1 vs 46 ± 16 μmol · kg -1 · hr -1). Leucine balance also improved significantly (-41 ± 13 μmol ·kg -1 · hr -1 vs -8 ± 16 μmol · kg -1 · hr -1; p = 0.01) because of a combination of an increased amount of leucine being used for protein synthesis and a lower amount of leucine coming from protein breakdown. Plasma cystine concentration, the only amino acid below the reference range in the supplemented group, was highly predictive for protein synthesis in that group. We conclude that the administration of amino acids to preterm infants from birth onward seems safe and prevents the loss of protein mass. (J P EDIATR 1995;127:458-65)

Appearance of nutrients in the blood of the golden perch Macquaria ambigua following feeding

1. 1. The appearance of nutrients in the systemic blood following feeding were investigated in an Australian freshwater fish, the golden perch ( Macquaria ambigua). 2. 2. Total gut transit time of a single meal was found to be 96.9 hr (SE = 10.13 hr, N = 9) which is greater than has been described for other species. 3. 3. A significant peak in total amino acid concentration was observed at 24 hr after feeding. Total non-essential amino acids concentration was significantly above control levels by 9 hr, and peaked at 24 hr after feeding, while total essential amino acid concentration did not rise significantly until 12hr and did not peak until 36 hr after feeding. In addition, the relative proportion of essential amino acids found in the blood following feeding was greater than would be expected based on the composition of the diet. 4. 4. No significant variations were seen in glucose, free fatty acids, β-hydroxybutyrate, lactate or total protein concentration as a result of feeding.

Milk Protein Quality in Low Birth Weight Infants

Growth rates (weight, length, and head circumference) and selected biochemical indexes of protein metabolism (serum urea, acid-base status, and plasma amino acid concentrations) were determined in low birth weight (LBW) infants appropriate for gestational age (birth weight less than 1,650 g) fed three formulas differing only in the whey-to-casein ratios: 60/40, 50/50, and 35/65. A group of infants fed exclusively human milk protein (HMP)-fortified human milk was used as a control. All diets provided similar daily protein and energy intakes, which were 3.5 g/kg and 122 kcal/kg in the human milk-fed infants and 3.3 g/kg and 121 kcal/kg in the formula-fed infants. Neither weight gain nor rate of growth in length and head circumference differed between the feeding groups and reached intrauterine or better rates in all groups. Values for serum urea and acid-base status were normal and also did not differ among the groups. At the end of the study, plasma threonine concentrations were significantly higher in all formula-fed infants than in the infants fed human milk. The highest plasma threonine concentration was found in the infants receiving the whey-predominant formula. Plasma concentrations of valine, methionine, and phenylalanine were also significantly higher in all formula-fed groups when compared with the human milk group. Plasma total essential amino acid concentrations were also significantly higher in the formula-fed infants than in the human milk fed. The results show that protein quality does not affect growth rate or biochemical indexes of metabolic tolerance in LBW infants fed adequate protein and energy intakes.(ABSTRACT TRUNCATED AT 250 WORDS)

Milk Protein Quality in Low Birth Weight Infants

Growth rates tweight, length, and head circumference) and selected biochemical indexes of protein metabolism (serum urea, acid‐base status, and plasma amino acid concentrations) were determined in low birth weight (LBW) infants appropriate for gestational age (birth weight &lt; 1,650 g) fed three formulas differing only in the whey‐to‐casein ratios: 60/40, 50/50, and 35/65. A group of infants fed exclusively human milk protein (HMP)‐fortified human milk was used as a control. All diets provided similar daily protein and energy intakes, which were 3.5 g/kg and 122 kcal/kg in the human milk‐fed infants and 3.3 g/kg and 121 kcal/kg in the formula‐fed infants. Neither weight gain nor rate of growth in length and head circumference differed between the feeding groups and reached intrauterine or better rates in all groups. Values for serum urea and acid‐base status were normal and also did not differ among the groups. At the end of the study, plasma threonine concentrations were significantly higher in all formula‐fed infants than in the infants fed human milk. The highest plasma threonine concentration was found in the infants receiving the whey‐predominant formula. Plasma concentrations of valine, methionine, and phenylalanine were also significantly higher in all formula‐fed groups when compared with the human milk group. Plasma total essential amino acid concentrations were also significantly higher in the formula‐fed infants than in the human milk fed. The results show that protein quality does not affect growth rate or biochemical indexes of metabolic tolerance in LBW infants fed adequate protein and energy intakes. However, further modifications of formula proteins are necessary if the goal of formula feeding is to achieve similar plasma amino acid patterns as in infants fed exclusively HMP.