Percentage Of Total Amino Acids Research Articles

Peculiarities in the Amino Acid Composition of Sow Colostrum and Milk, and Their Potential Relevance to Piglet Development

The composition of mother's milk is considered the ideal diet for neonates. This study investigated how conserved or variable the amino acid profile of sow colostrum and milk is throughout lactation, compared with other studies in sows and other species. Twenty-five sows (parity one to seven) from one farm with gestation lengths of 114 to 116 d were sampled on d 0, 3, and 10 after parturition. The total amino acid profile of the samples was analyzed through ion-exchange chromatography, and the results were displayed as the percentage of total amino acid and compared with literature data. Most of the amino acid concentrations in sow milk decreased significantly (p < 0.05) throughout the lactation period, while the amino acid profile generally showed a conserved pattern, especially from d 3 to d 10, and was rather similar across different studies. Glutamine + glutamate was the most abundant amino acid in milk at all sampling moments, accounting for 14-17% of total amino acids. The proportions of proline, valine, and glycine in sow milk nearly accounted for 11%, 7%, and 6% respectively, and were higher compared to human, cow, and goat milk, while the methionine proportion was less than the other three. Compared to the large variations often reported in macronutrient concentrations, the amino acid profile of sow milk in the present study, as well as in others, seems well conserved across the lactation period. Similarities with characteristic differences were also observed between sow milk and piglet body composition, which might reflect the nutrition requirements of preweaning piglets. This study warrants further research exploring the link between the whole amino acid profile and the particular amino acids for suckling piglets and could facilitate insight for optimizing creep feed.

Combined analysis of silk synthesis and hemolymph amino acid metabolism reveal key roles for glycine in increasing silkworm silk yields

Rearing silkworms (Bombyx mori) using formula feed has revolutionized traditional mulberry feed strategies. However, low silk production efficiencies persist and have caused bottlenecks, hindering the industrial application of formula feed sericulture. Here, we investigated the effects of formula feed amino acid composition on silk yields. We showed that imbalanced amino acids reduced DNA proliferation, decreased Fib-H, Fib-L, and P25 gene expression, and caused mild autophagy in the posterior silk gland, reducing cocoon shell weight and ratio. When compared with mulberry leaves, Gly, Ala, Ser, and Tyr percentages of total amino acids in formula feed were decreased by 5.26%, while Glu and Arg percentages increased by 9.56%. These changes increased uric acid and several amino acids levels in the hemolymph of silkworms on formula feed. Further analyses showed that Gly and Thr (important synthetic Gly sources) increased silk yields, with Gly increasing amino acid conversion efficiencies to silk protein, and reducing urea levels in hemolymph. Also, Gly promoted endomitotic DNA synthesis in silk gland cells via phosphoinositide 3-kinase (PI3K)/Akt/target of rapamycin (TOR) signaling. In this study, we highlighted the important role of Gly in regulating silk yields in silkworms.

Phytochemical Constituents of Ulva Lactuca and Supplementation to Improve The Nile Tilapia (Oreochromis Niloticus) Haemato-Biochemical Status

This study was carried out to investigate the phytochemical constituents and biological screening of green algae (Ulva lactuca ) methanolic crude extract. The HPLC spectrum profile identified seven phenolic and flavonoid compounds namely: catechin, chlorogenic ,caffeic, quercetin, and major compounds, ellagic acid with 60.87 % and rutin with 33.40% of total area. The GC profile of fatty acids portions represented to relative distribution percentage were 9 compounds, the major fatty acids are lauric acid 55.0 % , caprylic acid 21.2 % , capric Acid was 19.8 and palmitic acid was 1.94% . The 17 amino acids produced from GC spectrum , the percentage of total amino acid were 25.98% .The most abundant amino acids were glutamic acid 2.34% , alanine 2.22 and aspartic 2.09, leucine 1.33 , valine 1.26 , phenylalanine 1.0 , therionine 0.98 and isoleucine 0.9%. of total amino acid. Tilapia (Oreochromis Niloticus) diets were divided into Ulva fermentation and multi enzymes, groups each with three different supplementations (LC, PRO, and LC + PRO). The result recorded the diets containing fermented Ulva with L-carnitine, probiotic ( LC+PRO) was the highest level of red blood cell ( RBCs , HGB) by 1.97 cmm , 10.63 g/d . Similarly, increase of Hematocrit (HCt) , WBCs, platelets, and lymphocytes due to the highest level of protein, albumin, and globulin in this diets also, U. lactuca contains a number of complex carbohydrates and polysaccharides. This study has revealed that U. lactuca seaweed is a rich source of protein ( 22% ) which is nutritionally superior to the terrestrial plant proteins and can be used to provide significant proportions of the protein requirements of fish as well as for human.

Oxaliplatin-Fluoropyrimidine Combination (XELOX) Therapy Does Not Affect Plasma Amino Acid Levels and Plasma Markers of Oxidative Stress in Colorectal Cancer Surgery Patients: A Pilot Study.

Chemotherapy for colorectal cancer may lower muscle protein synthesis and increase oxidative stress. We hypothesize that chemotherapy may worsen plasma amino acids (AAs) and markers of oxidative stress (MOS). Therefore, this study aimed to document plasma AAs and MOS before, during and after chemotherapy in colorectal cancer (CRC) surgery patients. Fourteen normal-weight CRC patients were enrolled one month after surgery and scheduled for oxaliplatin-fluoropyrimidine combination (XELOX) therapy. Venous blood samples for AA and MOS (malondialdehyde, MDA; 8-hydroxy-2’-deoxyguanosine, 8-OHdG) measurements were drawn in fasting patients before each oxaliplatin infusion at initiation (A), 1 month (B) and 3 months (C) of the therapy, and after XELOX had finished (6 months, D). The results showed that during XELOX therapy (from phase B to phase D), in comparison to baseline (phase A), the branched chain amino acid/essential amino acid ratio, branched chain amino acids expressed as a percentage of total AAs, and arginine expressed as a percentage of total AAs significantly decreased (p = 0.017, p = 0.028, p = 0.028, respectively). Plasma levels of MOS did not change significantly. This study indicates that XELOX therapy does not affect plasma AA levels or worsen oxidative stress.

Comparative study of the nutritional composition and toxic elements of farmed and wild Chanodichthys mongolicus

Information of the difference in quality between farmed and wild fish is central to better ensuring fish products produced in aquaculture meet regulatory and consumer requirements. Proximate composition, amino acid and fatty acid profiles, and toxic elements contents of farmed and wild Chanodichthys mongolicus were established and compared. Significantly higher crude protein content while lower moisture content in farmed fish compared to wild fish were observed (P<0.05). The percentages of total amino acids (TAA), total essential amino acids (TEAA), total non-essential amino acids (TNEAA) and total delicious amino acids (TDAA) in farmed fish were all significantly higher than those in the wild equivalent (P<0.05). Compared to the FAO/WHO recommended reference values, the ratios of TEAA/TAA (39.84%–40.33%) were comparable to 40% and TEAA / TNEAA (66.22%–67.60%) were above 60%. Fatty acid profiles in both farmed and wild C. mongolicus were dominated by monounsaturated fatty acid (MUFA), with farmed fish contained much more MUFA content compared to wild counterpart (P<0.05). Notably, wild fish exhibited significantly higher levels of total polyunsaturated fatty acid (PUFA) including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) than farmed fish (P<0.05). The EPA (C20:5n3) and linoleic acid (C18:2n6) were the predominant PUFA in wild and farmed C. mongolicus, respectively. Moreover, farmed fish displayed an overall lower toxic element levels (As, Cd, Pb and Hg) in comparison with wild fish, and both were far lower than the established limit standard. In conclusion, our results suggest that the nutritional quality of farmed C. mongolicus was inferior to their wild counterpart with respect to fatty acids nutrition, and therefore further studies should focus on the improving C. mongolicus diet in order to enhance the overall nutritional composition.

Proximate Chemical Composition of Sea Grapes Caulerpa racemosa (J. Agardh, 1873) Collected from a Sub-Tropical Coast

Background: Nutritional fact study has prime importance to make the species edible and commercially viable to the consumers. Proximate chemical composition and amino acid profile were investigated to understand the nutritional value and protein quality of an edible algae Caulerpa racemosa. Methods: Samples were collected randomly by hand from the intertidal zone of the sub-tropical coastal Island St. Martin’s Island from February 2013 to May 2014. Samples were preserved using standard methods for chemical analysis. Proximate composition was determined using standard methods, Kjeldahl method for protein, Soxhlet method for crude lipid, H2SO4 (0.3 N) and NaOH (0.5 N) for dietary fibre, muffle furnace method for moisture content, ion-exchange chromatography for amino acid and statistical package used for validating the data. Results: The result of the study reveals that C. racemosa contains higher amount of proteins (19.72±0.77%), crude lipid (7.65±1.19%) and fibre (11.51±1.32%) compared to other green and brown algae. The higher concentration of aspartic acid (12.7±0.2%) and glutamic acid (9.2±0.7%) were observed in C. racemosa, while histidine (2.6±0.7%), methionine (1.4±0.4%) and tyrosine (3.8±0.2%) were the limiting amino acids. Lysine (6.6±0.2%), leusine (6.9±0.6%), glycine (6.5±0.4%), arginine (6.4±0.3%), alanine (7.6±0.6%) and threonine (6.2±0.5%) were obtained at a higher percentage of total amino acids. Conclusion: This study suggests that C. racemosa could be potentially used as a nutritious and functional food item for human consumption. Further studies on this edible species should be focused on fatty acid composition, vitamins, non-starch polysaccharide constituents, trace elements and sensory perceptions in order to depict safer and versatile utilization.

Biochemical composition and amino acid profiles of Nannochloropsis granulata algal biomass before and after supercritical fluid CO2 extraction at two processing temperatures

To assess the effect of supercritical fluid CO2 (SCFCO2) extraction on the biochemical composition of algal biomass, samples of untreated Nannochloropsis granulata biomass (Initial) and residual biomass after SCFCO2 extraction at 70 and 90°C (C70 and C90) were analyzed. SCFCO2 extraction significantly reduced crude lipid content from 285.5g/kg to 256.2–256.3g/kg (P=0.032) and caloric content from 23.4MJ/kg to 23.0–23.1MJ/kg (P=0.004). Concomitantly, significant increases in ash content from 77.8g/kg to 83.8–86.2g/kg (P=0.002) and carbohydrate content from 149.1g/kg to 155.9–165.9g/kg (P=0.033) were observed and no significant differences between C70 and C90. Small, but significantly lower levels of crude protein (CP, N×6.25 or N×4.78) and non-protein N (NPN) were observed for C70 with no differences between Initial and C90. However, sum of amino acid (AA) residues (ΣAA), a more direct estimate of true protein content, indicated no significant difference in protein content (P=0.536) between treatments (average, 362.0g/kg). Only minor differences in total and free AA profiles were observed between Initial, C70 and C90 and the free AA content as percentage of total AA was insignificant (P=0.564) between treatments (average, 4.9%). However, several free essential AAs (EAAs) were significantly higher in C70 and C90 than Initial resulting in SCFCO2-extracted biomass having significantly higher (P=0.007) total free EAA content (2438.0–2697.0μg/g of DW) than Initial (2100.4μg/g of DW) indicating some protein damage and free EAA liberation. While there was a trend toward most AAs slightly increasing in C70 and C90, the EAA lysine; particularly sensitive to high-temperature processing, was significantly lower (P=0.003) in C90 (6.0g lysine/100g protein) than Initial (6.9g lysine/100g protein) while C70 was intermediate (6.4g lysine/100g protein) providing evidence that lysine damage was more severe at 90°C than 70°C. The essential AA index (EAAI) of 0.9 for N. granulata biomass is highly comparable to reference proteins such as egg albumin, soy, Chlorella and Spirulina (0.9–1.0) indicating very good potential for use in animal and fish feeds. Further investigations involving species-specific in vitro protein quality and in vivo biological performance of target animals fed diets supplemented with these products are warranted.

Amino Acid and Fatty Acid of Abalone Haliotis Squamata Cultured in Different Aquaculture Systems

The aim was to analyze the amino acid and fatty acid of abalone Haliotis squamata cultured in different aquaculture systems. The percentage of total amino acid of abalone cultured in laboratory, floating cage, and longline system valued 11.02%, 9.53% and 8.24%. respectively. Abalone contained 14 saturated fatty acids and 16 unsaturated fatty acids. The saturated fatty acids of abalone were dominated by palmitenoic acid (C16:0) and steraenoic acid (C18:0). The high percentage of unsaturated fatty acids in abalone were oleat acid (C18:1n9), linolenic acid (C18:3n3), arachidonoic acid (C20:4n6) and eicosapentaenoic acid/EPA (C20:5n3).

Changes in amino acids content of humic acids sequentially extracted from peat and sod–Podzolic soil

Vialykh, E. A., Ilarionov, S. A., Abdelrahman, H. M. and Vialykh, I. A. 2014. Changes in amino acids content of humic acids sequentially extracted from peat and sod–Podzolic soil. Can. J. Soil Sci. 94: 575–583. Amino acids (AA) and peptides are thought to be part of humic acids (HA), but debate whether they are an integral part of the HA is still going. Humic acids sequentially extracted from peat and sod-podzolic soil were analyzed for their AA content, elemental composition and by Fourier transform infrared spectroscopy. Extracted HA were hydrolyzed in 6 M HCl for 16 h for AA release, which was detected by a capillary electrophoresis system. Alanine, arginine, sum of aspartic acid and asparagine, sum of cysteic acid and cysteine, sum of glutamic acid and glutamine, glycine, histidine, leucine and isoleucine, lysine, methionine, phenylalanine, proline, serine, threonine, tyrosine, valine were identified. The total content of hydrolyzable AA in sod-Podzol HA increased by 6.2–8.2% with increasing the extraction cycles while an inverse tendency was observed for AA released from peat HA. Moreover, individual AA expressed as percentages of total AA were constant values with coefficients of variation lower than 20% for the studied HA.

Functional Properties of the Protein Isolate and Major Fractions of Pine Nut Proteins Prepared from the Changbai Mountain in China

The functional properties of protein isolate and major protein fractions prepared from Changbai Mountain pine nuts were investigated. Albumin, globulin, glutelin, and protein isolates were obtained after the Osborne method and alkaline dissolution and acid precipitation, and protein contents of the fractions are 48.02%, 81.93%, 83.02%, and 89.69%, respectively. For the sulfhydryl contents, albumin is the highest, and glutelin is the lowest. In a disulphide bond, the protein isolate content is the highest with a value of 28.74 μmol/g, and the glutelin content is the lowest with the value of 13.46 μmol/g. For the four kinds of proteins, the essential amino acids in percentage of total amino acids are 31.13%, 34.22%, 30.30%, and 34.54%, respectively. The pH dependent protein solubility profile reveals that the minimum solubility is at pH 5.0, which corresponds to the isoelectric point. Protein isolate has the minimum water absorption capacity with a value of 0.59 ml/g. On the other hand, albumin has the minimum oil absorption capacity with a value of 2.11 ml/g. The emulsifying activity and stability and the foaming activity and stability increased with increasing concentration of four kinds of proteins. SDS-PAGE results showed that these four kinds of proteins have different molecules.

Comparative study of proximate composition and amino acid in farmed and wild Pseudobagrus ussuriensis muscles

SummaryThe proximate composition and amino acid compositions of the muscle of wild and farmed Pseudobagrus ussuriensis were compared. The lipid content of the farmed fish was significantly higher, while moisture content was significantly lower, than those of the wild fish. Pseudobagrus ussuriensis protein has a well‐balanced amino acid composition. The percentages of total amino acids, essential amino acids, nonessential amino acids and delicious amino acids were significantly higher in the wild than those in farmed fish. The ratios of WEAA to WTAA (42.78%–43.02%) and WEAA to WNEAA (85.52%–87.74%) were comparable to the reference values of 40% and above 60% recommended by FAO/WHO. According to the amino acid scores, methionine would have been described as the first limiting amino acid, and Lys had the highest score for the protein in both wild and farmed Pseudobagrus ussuriensis. This study shows that Pseudobagrus ussuriensis under investigation have high nutritional qualities and are good protein resources.

太湖水体溶解性氨基酸的空间分布特征

Amino acids( AAs) are important bio-available components of organic matter( OM) and are the major forms of organic nitrogen( ON) in aquatic ecosystem. They also represent significant fractions of OM in recent coastal marine sediments,water column particles and dissolved organic matters. They are typically labile composed relative to bulk OM and ON,and account for a considerable portion of the particulate OC and ON recycled in both water column and sediments,and therefore are an important nutrient form. Owing to the different AAs monomers have different biogeochemical stability,AAs are often used as an indicator of organic matter sources and as an index of OM degradation potential. Changes in amino acid composition exhibit consistent trends and demonstrate the degradation of cellular organic matter as it sinks through water column and is incorporated into sediments. Due to the labile character of AAs,the percentage of OC and N represented by amino acid( AA-C / OC% and AA-N / ON%) and the percentage of total amino acids have proven to be useful degradation indicators. They are sensitive at different stages of OM alteration and appear uncompromised by source variation. Dissolved amino acids( DAAs) characteristics were investigated in water of Lake Taihu,a large,shallow and eutrophic freshwater lake in China. The northern lake is characterized by phytoplankton dominance,high water turbidity,and severe Microcystis spp. algal blooms. In contrast,eastern lake is characterized by submersed vegetation,clear water,and diverse communities of fishes and invertebrates. The main upstream land use types of south Taihu were classified by the mountain forests and farmland. DAAs concentrations in Taihu ranged from 0. 27 to 3. 95 μmol / L,with a mean value of 1.38 μmol / L. The large regional differences in concentrations and yields of DAAs suggested that DOM produced in situ is an important source of bio-reactive of organic matter in waters of Taihu. The spatial distributions of DAAs concentrations in Taihu were less variable than those previously reported from other aquatic environments. DAAs concentrations of north Taihu were significantly higher than south lake and east lake,with mean values of( 2. 59±0. 71) μmol / L in north Taihu,( 0. 48±0. 14) μmol / L in south Taihu,and( 0. 48 ± 0. 16) μmol / L in east Taihu,respectively( P 0. 001). Based on the relationship between amino acid yields and percent labile DOC,( 17. 65 ±17. 84) % of fresh DOC in north lake is labile,which is higher than in south lake or east lake. The results showed internal sources mainly from the decomposing of phytoplankton should be the main source of DAAs in Taihu,and DAAs was important fraction of DOM. DAAs compositions were dominated by Phenylalanine( PHE) and lysine( LYS) in north lake,while only LYS in south and east lake.Compositions and concentrations of DAAs can be possible used as an indicator,which could provide useful information about the nutritional status and bio-available DOM in Lake Taihu. But because of high spatial heterogeneity in Taihu,we need to establish DAAs-liable DOC linear model for Lake Taihu,by the means of the algal-dominated and macrophytedominated DOM degradation experiments.

Soybean meal substitution with a yeast-derived microbial protein source in dairy cow diets

The objective of this study was to examine the effects substituting soybean meal with a yeast-derived microbial protein (YMP) on rumen and blood metabolites, dry matter intake, and milk production of high-producing dairy cows. Sixteen Holstein cows (12multiparous and 4 primiparous), 93±37 DIM (mean ± SD) at the beginning of the experiment, were used in a 4×4 Latin square design with four 28-d periods. Cows were blocked by parity and production, with 1 square consisting of 4 animals fitted with rumen cannulas. Basal diets, formulated for 16.1% crude protein and 1.56Mcal/kg of net energy for lactation, contained 40% corn silage, 20% alfalfa hay, and 40% concentrate mix. During each period, cows were fed 1 of 4 treatment diets corresponding to YMP (DEMP; Alltech Inc., Nicholasville, KY) concentrations of 0, 1.14, 2.28, and 3.41% DM. Soybean meal (44% CP) was replaced by YMP to attain isonitrogenous and isoenergetic diets. Dietary treatments had no effect on pH and on most ruminal volatile fatty acid concentrations, with the exception of isovalerate, which decreased linearly with the addition of YMP. Rumen ammonia concentration decreased linearly, whereas free amino acids, total amino acid nitrogen, and soluble proteins weighing more than 10kDa showed a cubic response on rumen N fractionation. A quadratic response was observed in oligopeptides that weighed between 3 and 10kDa and peptides under 3kDa when expressed as percentages of total amino acids and total nitrogen. Although nonesterified fatty acid concentration in blood did not differ between treatments, β-hydroxybutyrate and plasma glucose increased linearly as YMP increased. Dry matter intake showed a cubic effect, where cows fed 1.14, and 3.41% YMP had the highest intake. Milk production was not affected by YMP, whereas a trend was observed for a quadratic increase for 4% fat-corrected milk and energy-corrected milk. Medium- and long-chain fatty acid concentrations in milk increased quadratically, which elicited similar effects on milk fat concentration and yield. Total solids percentage and yield, and milk urea nitrogen also showed quadratic effects as YMP increased in the diet. No effects were observed on feed efficiency, milk protein, and lactose percentage or yield. A complementary in vitro study demonstrated a quadratic tendency for apparent and true dry matter digestibility as YMP was added to the diet. It was concluded that the substitution of soybean meal with YMP increased the percentage of total solids in milk and tended to improve energy-corrected and fat-corrected milk production in high-producing dairy cows consuming high-forage diets.

INFLUENCE OF EFFECTIVE MICRO-ORGANISMS, SEAWEED EXTRACT AND AMINO ACIDS APPLICATION ON GROWTH, YIELD AND BUNCH QUALITY OF RED GLOBE GRAPEVINES

This investigation was conducted for two successive seasons (2007 & 2008) in a private vineyard located at El-Khatatba, Menoufiya governorate; to study the influence of effective micro-organisms, seaweed extract and amino acids application on growth, yield and bunch quality of Red Globe grapevines. The chosen vines were eight-year-old, grown in a sandy loam soil, spaced at 2 X 3 meters apart and irrigated by the drip irrigation system, cane-pruned and trellised by Spanish Parron system. Two rates of the conducted treatments were applied through soil drenching: effective micro-organisms (EM) at 10 or 20 cm/vine; seaweed extract (Gifert) at 10 or 20 cm/vine and amino acids (Pepton) at 0.5 or 1.0 g/vine at three dates: the 1st date after bud burst stage, the 2nd date after fruit set stage, and the 3rd one at veraison stage. Nine treatments were applied as follows:- Control (untreated vines); EM (10 cm/vine) (EM1); EM (20 cm/vine) (EM2); Gifert (10 cm/vine) (G1); Gifert (20 cm/vine) (G2); Pepton (0.5 g/vine) (P1); Pepton (1.0 g/vine) (P2);EM1 + G1 + P1 and EM2 + G2+ P2. The results showed that the combined application of EM, Gifert and Pepton at the higher rate gave the best results in comparison with control followed by the lower rate of the same combined products. This treatment resulted in the best yield and its components as well as the best physical characteristics of bunches, improved physical and chemical characteristics of berries and ensured the best vegetative growth parameters. Total chlorophyll and percentages of total amino acids, nitrogen, phosphorus and potassium in the leaves and total carbohydrates in the canes were increased. With respect to microbiological activity in the rhizosphere, it was noticed that total spore forming; the populations of total microorganism; dehydrogenase and phosphatase enzymes activity increased in the rhizosphere as a result of the combined application of EM, Gifert and Pepton at the higher rate. On the other hand, control was found to record the minimum values of these characters. The economical study indicated that the combined application of EM, Gifert and Pepton at the higher rate on Red Globe grapevines gave the highest net income as compared to the control.

Estimation of copepod trophic niche in the field using amino acids and marker pigments

In this study, marker pigments analysed in incubation feeding experiments and monthly amino acid composition (AAC, weight percentage of total amino acids yields) of copepods collected over 1 yr from the field were used to estimate the food niche of 4 co-occurring copepod species: Acar- tia clausi, Oithona nana, Temora longicornis and Euterpina acutifrons. Both marker pigments and AAC of copepods are good indicators of copepod food niche. Marker pigments are indicators of the autotrophic food ingested by copepods and AAC is an indicator of both autotrophic and non- autotrophic food needed by copepods to maximise reproductive success. Marker pigments showed that copepod species fed selectively on the phytoplankton community and that copepod species had different diets. A. clausi fed mainly on chlorophytes and diatoms, E. acutifrons on diatoms and chloro- phytes, T. longicornis on dinoflagellates and diatoms, and O. nana on dinoflagellates and prymnesio- phytes. Each copepod species had its own specific AAC and, furthermore, there was a significant relationship between similarity in AAC among copepod species and similarity in the phytoplankton classes ingested by them, indicating that the differences in the AAC among copepod species were due to different food resources. As a higher copepod reproductive success is observed when the AAC of the food is more similar to the AAC of the copepods, this selective feeding behaviour could be due to the necessity of a diet with an AAC balanced in an optimal proportion. The food niche partitioning observed in this study might contribute to the coexistence of these copepod species in their habitat.

A Key Point Mutation (V156E) Affects the Structure and Functions of Human Apolipoprotein A-I

A Key Point Mutation (V156E) Affects the Structure and Functions of Human Apolipoprotein A-I

Nutrients in edible mushrooms: an inter-species comparative study

A comparative study on various components of nutritional interest, such as water, protein, total amino acids, ash and minerals, in mushrooms of different species ( Pleurotus ostreatus, Pleurotus eryngii, Pleurotus pulmunarius and Lentinula edodes) was carried out. Mushrooms were cultivated on the same compost (wheat straw added with 15% of sugar beet) and analysed immediately after harvest to avoid any interfering parameters. The limiting amino acid was also evaluated and the relevant protein chemical score was calculated. The moisture content of the edible mushrooms studied is high (ranging from 85.2 to 94.7%) and the ash contents range from 6.9 to 10.5% on a dry basis. Potassium is the most abundant mineral element followed by magnesium. Total nitrogen varies from 3.47 to 7.93% (dry basis), and P. ostreatus species has the largest variability among the samples analysed. The most abundant amino acids in mushrooms, expressed as percentages of total amino acids, are glutamic acid (12.8–20.9%), aspartic acid (9.1–12.1%) and arginine (3.7–11.7%), but in the analysed P. pulmunarius and L. entinus edodes a particularly low percentage of arginine (3.7 and 5.7%) has been detected. The chemical score generally ranges from 96 to 110%, the limiting amino acid being leucine or/and lysine. ©

Research Note: Characterization of Two Samples of Corn that Vary in Bushel Weight

Two samples of corn differing substantially in bushel weight were obtained from a commercial feed mill. The light weight sample (606 g/L; 47 lb/bu) was higher in protein (9.3%) and lower in ether extract (2.95%) than the normal weight corn (696 g/L; 54 lb/bu), which contained 8.1% protein and 3.43% ether extract. The determined TME of the corn samples on a dry matter basis did not differ significantly (3.81 vs. 3.83 kcal/kg). The normal corn had increased levels of lysine, methionine, and methionine plus cystine when the amino acid levels were compared as a percentage of total amino acids. No differences were observed when comparisons were made as a percentage of the total sample. In the light corn sample, the analyzed lysine and sulfur amino acid concentrations (percentage amino acids/percentage CP) were 13 to 16% lower than calculated values derived from published prediction equations. In the normal corn, the differences were only 8 and 3%, respectively.

Response to Abomasal Infusion of Methionine of Weaned Dairy Calves Fed a Complete Pelleted Starter Ration Based on By-Product Feeds1,2

Three abomasal infusion trials were to determine the first-limiting amino acid for nitrogen retention of postweaned Holstein bull calves fed a starter ration based on cereal by-product feeds. Ration ingredients contributed the following percentages of total amino acids: wheat middlings 38, brewer's grains 24, hominy feed 21, oat hulls 10, distiller's grains 6, and molasses 1. Dry matter of the pelleted ration contained 13 to 14% crude protein and .23 to .26% sulfur. Each trial was a replicated 4 × 4 Latin square with 9-day periods. Calves were weaned at 4 wk and infusions initiated at 5 to 6 wk of age. Abomasal infusion of the 10 essential amino acids, an isonitrogenous quantity of an equimolar mixture of alanine, asparagine, glutamate, glycine, and serine, or an isocaloric quantity of glucose indicated that essential amino acid(s) rather than nonspecific nitrogen or energy was limiting protein synthesis. Quadratic responses in urine nitrogen excretion and retained nitrogen occurred when 0, .3, .6, and 1.2g L-methionine/kg starter ration were infused. Greatest responses occurred with .6g methionine, which increased retained nitrogen 11 and 19% and decreased urine nitrogen 7 and 10%. The relationship between infused methionine and plasma methionine was linear. Infusions in all trials had no effect on digestibility of energy and nitrogen.

Role of Gut Flora in the Transfer of Amino Acids Through a Marine Food Chain

The gut of the sea urchin Strongylocentrotus droebachiensis has between 2 × 108 and 6 × 109 bacteria/mL of gut contents. When these bacteria are present, radioactive carbon fed to the urchins as either glucose or cellulose appears in all of the protein amino acids of the gonads. However, when the gut flora is suppressed by a mixture of antibiotics, injection of the sea urchins with radioactive glucose results in the labeling of some of the amino acids (nonessential amino acids) but not others (essential amino acids). These results imply that: (a) sea urchins have the ability to digest cellulose, probably with the aid of the gut flora; (b) intestinal microorganisms can synthesize essential amino acids; and (c) amino acids of microbial origin are available to the sea urchins. The amino acid compositions of (i) kelp (Laminaria longicruris), (ii) sea urchin intestinal microflora, and (iii) sea urchins, were determined over a yearly cycle. The amino acid composition of kelp and microbes were compared as a source of nutrient for the sea urchins, using as indications: overall similarity in compositions, essential amino acid index, and percentage of total amino acid that is essential. All three comparative methods show that the microbial protein is of higher nutritive value than the kelp protein.Key words: amino acids, nitrogen, bacteria, kelp, Laminaria longicruris, sea urchin, Strongylocentrotus droebachiensis