Muscle Amino Acid Research Articles

Interactive effects of glutamine and gamma-aminobutyric acid on growth performance and skeletal muscle amino acid metabolism of 22-42-day-old broilers exposed to hot environment.

The present experiment was conducted to investigate the interactive effects between dietary glutamine (Gln, 0 and 5g/kg) and gamma-aminobutyric acid (GABA, 0 and 100mg/kg) on growth performance and amino acid (AA) metabolism of broilers under hot environment. A total of 360 22-day-old Arbor Acres male chickens were randomly assigned to five treatment groups under thermoneutral chamber (PC, 23°C) and cyclic heat stress (HS, 30-34°C cycling) conditions. Compared with the PC group, cyclic HS decreased (P < 0.05) daily weight gain (DWG), daily feed consumption (DFC), the concentrations of Gln, glutamate (Glu), and GABA, and the activities of glutaminase and glutamic acid decarboxylase (GAD) in breast muscle at 28, 35, and 42days, while it increased (P < 0.05) the activities of glutamine synthetase (GS) and gamma-aminobutyric acid transaminase (GABA-T) at 28, 35, and 42days. Dietary Gln and GABA improved (P < 0.05) DWG and DFC of broilers under cyclic HS during 28-42days. In breast muscle, the Gln supplementation increased (P < 0.05) the concentrations of Gln (28, 35, and 42days), Glu (28, 35, and 42days), and GABA (42days) and the activities of glutaminase (28, 35, and 42days) and GAD (28, 35, and 42days) but decreased (P < 0.05) GS activities at 28, 35, and 42days and GABA-T activities at 28days. The addition of GABA increased (P < 0.05) the concentrations of Gln and Glu and activities of glutaminase and GAD, while it decreased (P < 0.05) GABA-T activities at 28, 35, and 42days. Significant interactions (P < 0.05) between Gln and GABA were found on breast skeletal muscle Gln concentrations, glutaminase activities, GS activities at 28 and 35days, and DWG, GABA concentrations, and GABA-T activities at 28, 35, and 42days in broilers under cyclic HS. In conclusion, the present results indicated that the interactions of exogenous Gln and GABA could offer a potential nutritional strategy to prevent HS-related depression in skeletal muscle Gln and GABA metabolism of broilers.

Effect of Feeding a Mixed Microbial Culture Fortified with Trace Minerals on the Performance and Carcass Characteristics of Late-fattening Hanwoo Steers: A Field Study.

This study was conducted to determine the effects of feeding a trace minerals-fortified microbial culture (TMC) on the performance and carcass characteristics of late-fattening Hanwoo steers. A mixture of microbes (0.6% [v/w] of Enterobacter sp., Bacillus sp., Lactobacillus sp., and Saccharomyces sp.) was cultured with 99% feedstuff for ensiling and 0.4% trace minerals (zinc, selenium, copper, and cobalt). Sixteen late-fattening steers (mean age, 21.8 months) were allocated to two diets: a control diet (concentrate mix and rice straw) and a treated diet (control diet+3.3% TMC). At a mean age of 31.1 months, all the steers were slaughtered. The addition of TMC to the diet did not affect the average daily weight gain of the late fattening steers, compared with that of control steers. Moreover, consuming the TMC-supplemented diet did not affect cold carcass weight, yield traits such as back fat thickness, longissimus muscle area, yield index or yield grade, or quality traits such as meat color, fat color, texture, maturity, marbling score, or quality grade. However, consumption of a TMC-supplemented diet increased the concentrations of zinc, selenium, and sulfur (p<0.05) in the longissimus muscle. With respect to amino acids, animals consuming TMC showed increased (p<0.05) concentrations of lysine, leucine, and valine among essential amino acids and a decreased (p<0.05) concentration of proline among non-essential amino acids. In conclusion, the consumption of a TMC-supplemented diet during the late-fattening period elevated the concentrations of certain trace minerals and essential amino acids in the longissimus muscle, without any deleterious effects on performance and other carcass characteristics of Hanwoo steers.

Analysis of meat flavor compounds in pedigree and two-strain Yangzhou geese

In this study, we evaluated the meat flavor compounds of Yangzhou geese, including one group of pedigree strain (AA group) and 4 groups of 2-strain crossbreds (KA, KB, CA, and SA). Each group consisted of 100 geese comprised of 5 replicates of 10 males and 10 females each. Inosine 5′-monophosphate (IMP), amino acid (AA), and fatty acid (FA) levels in breast and thigh muscle were determined. Results showed that AA group had the highest levels of total amino acid (TAA) and dissolved free amino acids (DFAA) in breast muscle and of polyunsaturated fatty acids (PUFA) in thigh muscle (P < 0.05). In SA group, the levels of C17:1, C22:0, C22:1, C20:4, and C24:1 in breast muscle were significantly higher in SA than in other groups (P < 0.05). KB group had the lowest glycine levels in breast muscle (P < 0.05) while MUFA levels were significantly higher in KB than in other groups (P < 0.05). In KA, the levels of C18:3 in breast muscle in were higher than in CA and KB (P < 0.05). CA had relevant higher IMPc levels in breast muscle than SA (P < 0.05) and other groups (P > 0.05); however, no significant differences were obtained in thigh muscle (P > 0.05). In conclusion, Yangzhou AA goose has high levels of meat flavor compounds than its crossbreeds. Future efforts should focus on assessing meat flavor through measurement of sensory characteristics of Yangzhou geese.

Impact of combined resistance and aerobic exercise training on branched-chain amino acid turnover, glycine metabolism and insulin sensitivity in overweight humans.

Obesity is associated with decreased insulin sensitivity (IS) and elevated plasma branched-chain amino acids (BCAAs). The purpose of this study was to investigate the relationship between BCAA metabolism and IS in overweight (OW) individuals during exercise intervention. Whole-body leucine turnover, IS by hyperinsulinaemic-euglycaemic clamp, and circulating and skeletal muscle amino acids, branched-chain α-keto acids and acylcarnitines were measured in ten healthy controls (Control) and nine OW, untrained, insulin-resistant individuals (OW-Untrained). OW-Untrained then underwent a 6 month aerobic and resistance exercise programme and repeated testing (OW-Trained). IS was higher in Control vs OW-Untrained and increased significantly following exercise. IS was lower in OW-Trained vs Control expressed relative to body mass, but was not different from Control when normalised to fat-free mass (FFM). Plasma BCAAs and leucine turnover (relative to FFM) were higher in OW-Untrained vs Control, but did not change on average with exercise. Despite this, within individuals, the decrease in molar sum of circulating BCAAs was the best metabolic predictor of improvement in IS. Circulating glycine levels were higher in Control and OW-Trained vs OW-Untrained, and urinary metabolic profiling suggests that exercise induces more efficient elimination of excess acyl groups derived from BCAA and aromatic amino acid (AA) metabolism via formation of urinary glycine adducts. A mechanism involving more efficient elimination of excess acyl groups derived from BCAA and aromatic AA metabolism via glycine conjugation in the liver, rather than increased BCAA disposal through oxidation and turnover, may mediate interactions between exercise, BCAA metabolism and IS. Clinicaltrials.gov NCT01786941.

Muscle metabolism and whole blood amino acid profile in patients with liver disease

Objective. Branched-chain amino acids (BCAA) are used in liver cirrhosis to promote protein synthesis, support ammonia detoxification, and treat hepatic encephalopathy. Cirrhosis leads to subnormal BCAA plasma concentrations and studies indicate that levels are decreased due to their role in muscle ammonia removal. Muscle contribution has not been fully elucidated. We studied muscle amino acid metabolism in six healthy subjects, 13 cirrhosis patients and six patients with an episode of alcoholic hepatitis. Methods. Subjects had catheters inserted into the femoral artery and vein to obtain arterial (A) and venous (V) concentrations of amino acids (μmol/L blood). Results. BCAA concentrations were lower in patients with cirrhosis compared to healthy subjects (p < 0.05) with no difference between patients with alcoholic hepatitis and the other groups. Muscle BCAA uptake was variable and on average higher in patients with alcoholic hepatitis and patients with stable cirrhosis compared to healthy subjects (mean A-V difference 0.5 and 32 vs. − 12 μmol/L blood) (p = 0.22). The release of aromatic amino acids (AAA) was comparable in the three groups (P > 0.30). The BCAA/AAA (Fischer's ratio) was lower in patients with cirrhosis and patients with alcoholic hepatitis compared to healthy subjects (mean 1.65, 1.17 and 2.73, both p < 0.05) and it was negatively correlated to the Child-Pugh score (p < 0.05). Conclusions. Patients with liver disease have lower BCAA and higher AAA blood concentrations compared to healthy subjects. The trend towards an increased muscle uptake of BCAA may have contributed but this was not significant.

Nutritional evaluation ofTenebrio molitormeal as fishmeal substitute for tilapia (Oreochromis niloticus) diet

Fishmeal (FM) and soy meal (SM) are the most common protein sources used in fish feed, but they are associated with environmental, economic or production problems. Insects could be an interesting alternative source of protein. This work investigates the nutritive value of Tenebrio molitor meal (TM) and the effect of total replacement of SM by TM (TM/FM diet) or partial replacement of FM by TM (TM/FM/SM diet) versus a diet based in SM and FM (FM/SM diet) for tilapia. We studied the chitin content in TM, the in vitro protein digestibility, protease activity, oxidative stress and antioxidant defences, growth performance and nutrient utilization. The results indicate that an inclusion up to 500 g kg−1 of TM in the diet did not affect feed intake, in vitro protein digestibility, muscle amino acid composition or biometric indexes. However, their inclusion reduced growth performance and affected the muscle fatty acid profile. The lowest values for protease activity, elevated FRAP in digestive tracts and ROS level in muscle and higher SOD activity were observed in fish fed with SM/FM diet. The use of TM requires better understanding of the role of chitin in digestion and the study of toxins that might affect fish growth.

Creatine Supplementation Increases Muscle Branched‐Chain Amino Acids in an Alzheimer Mouse Model

Besides mental dysfunctions, Alzheimer's disease (AD) may impair muscle function. Creatine supplementation (CR) can enhance skeletal muscle mass and function in sarcopenia and muscular dystrophies, but has yet to be studied in AD. We examined the effect of oral CR on muscle amino acids (AA) level in an AD model.24 triple transgenic (3×Tg, ~8 mo old) AD mice were randomly assigned to control (CON; 6 males (M)/6 females (F)) or CR (3% w/w; 4M/8F) diet. Bodyweights and feed intakes were measured throughout the 8‐week study. Quadriceps muscle (QM) was collected at the end to analyze for levels of creatine and AA and measured by high‐performance liquid‐chromatography. Data (mean±SEM) were analyzed by 2‐way ANOVAs.Feed intakes and changes in bodyweight were similar among groups (p&gt;0.05). Creatine content in QM was higher (p=0.067) in CR (M: 0.38±0.04, F: 0.38±0.02 nmol/μl) vs. CON (M: 0.33±0.01, F: 0.35±0.01 nmol/μl). Total branched‐chain AA (BCAA) level in QM was greater for CR (M: 111.10±8.51, F: 87.26±4.31 nmol/mg tissue) vs. CON (M: 78.56±4.46, F: 66.07±4.35 nmol/mg tissue). BCAA/non‐BCAA ratio was higher (p=0.002) in CR (M: 0.87±0.17, F: 0.58±0.03) vs. CON (M: 0.54±0.04, F: 0.45±0.03). Particularly, leucine was dramatically increased (p&lt;0.0001) in CR (M: 61.15±5.64, F: 47.28±2.55 nmol/mg) vs. CON (M: 34.21±2.64, F: 25.49±2.38 nmol/mg).CR supplementation enhances muscle AA contents, increasing BCAA levels in the 3×Tg AD mouse model, which may promote muscle function in AD.Funded by CIHR and Everett Endowment Fund

Nutritional Responses of Round Goby (Neogobius melanostomus) caught from Rhine River (Germany) as a Wild Species to Different Fish Oils

This study was aimed to determine the effects of food supplementation with different levels of two types of fish oil (anchovy and menhaden oils), on growth and the composition of fatty acids and essential amino acids in muscle of a wild and alien species. In this study round goby (Neogobius melanostomus) caught from Rhine River (0.95–1.0 g fresh mass) were fed for 47 days diets containing 5% anchovy oil (AO), 5% menhaden oil (MO) or 2.5% AO+2.5% MO. Fish were cultured in indoor 40 L aquaria (12 aquaria in total). The feeding rate was adjusted to 10% of the fish fresh mass per day and water temperature was constantly maintained at 19°C. After 47 days, no differences were observed in weight gain, specific growth rate (SGR), feed conversion ratio (FCR) and condition factor (P>0.05). The lowest FCR was found in AO diet. Muscle fatty acid composition was influenced by dietary fish oils, and fish fed the AO diet have shown slightly higher contents of eicosapentaenoic and docosahexaenoic acid in their muscle. Muscle amino acid composition was not affected by the diet, an except for leucine. The results indicated that addition of fish oil is important in maintaining the content of n-3 fatty acids in fish in aquaculture.

Regulation of free glutamate content in meat by dietary lysine in broilers.

Regulation of taste is important for improving meat quality and glutamate (Glu) is one of the important taste-active components in meat. Here, the effects of dietary lysine (Lys) content on taste-active components in meat, especially free Glu, were investigated. Fourteen-day-old broiler chicks (Gallus gallus) were fed on diets containing 100% or 150% of the recommended Lys content for 10 days. Concentrations of free amino acids in plasma, muscle and liver were measured. The levels of messenger RNAs (mRNAs) for enzymes related to Glu metabolism were determined in muscle and liver. The concentration of muscle metabolites was also determined. The free Glu content in muscle of chicks fed the Lys150% diet was increased by 44.0% compared with that in chicks fed the Lys100% diet (P < 0.01). The mRNA level of lysine α-ketoglutarate reductase, which is involved in Lys degradation and Glu production, was significantly increased (P < 0.05) in the Lys150% group. Metabolome analysis showed that the Lys degradation products, muscular saccharopine, pipecolic acid and α-aminoadipic acid, were increased in the Lys150% group. Our results suggest that free Glu content in muscle is regulated by Lys degradation. These results suggest that a short-term feeding of high-Lys diet could improve the taste of meat.

Whole-body and muscle amino acid composition of Plata pompano (Trachinotus marginatus) and prediction of dietary essential amino acid requirements

Summary Background: knowing the essential amino acid (EAA) requirement values is fundamental to formulate good quality and cost-effective fish feeds. However, such requirements have been established for few fish species. The estimation of amino acid requirements based on amino acid composition of fish is a fast and reliable alternative. Objective: to determine whole-body and muscle amino acid composition of Plata pompano (Trachinotus marginatus) and estimate its EAA requirements. Methods: EAA requirements were estimated using A/E ratios [(Individual EAA ⁄ Total EAA) * 1000]. Results: hystidine, leucine, lysine and phenylalanine were present in higher concentrations in muscle tissue in comparison with the whole-body. On the other hand, arginine, isoleucine, methionine, tryptophan and valine concentration were not different between whole-body and muscle. A/E ratios for Plata pompano determined in the present study are similar to those reported in other fish species, although valine A⁄E ratios were slightly smaller. Conclusion: until dose-response experiments are conducted to precisely determine EAA requirements, the estimated EAA values using whole-body EAA-as proposed in this study-could be used to formulate diets for Plata pompano. Key words: A ⁄E ratio, Carangidae, diet formulation, fish nutrition.. Resumen Antecedentes: conocer los requerimientos de aminoácidos esenciales (EAA) es fundamental para la formulación de raciones rentables y de buena calidad para peces. Sin embargo, dichos requerimientos se han establecido solo para unas pocas especies de peces. La determinación de las necesidades de aminoácidos basada en la composición de aminoácidos de los peces es un método alternativo rápido y viable. Objetivo: determinar la composición de aminoácidos del cuerpo completo y del músculo del Pámpano (Trachinotus marginatus) y estimar sus necesidades de EAA. Métodos: el requerimiento de aminoácidos esenciales se calculó utilizando el índice A/E [(Individual EAA⁄Total EAA) * 1000]. Resultados: la histidina, leucina, fenilalanina y lisina estaban en una mayor concentración en el músculo que en el cuerpo. Por otro lado, arginina, isoleucina, metionina, triptófano y valina no mostraron ninguna diferencia significativa entre la composición del músculo y el cuerpo. Los valores de A/E para Pámpano determinados en este estudio son similares a los reportados para otras especies de peces, pero no los de valina, que fue levemente menor. Conclusiones: hasta que no sean realizados experimentos de dosis-respuesta para determinar con precisión los requerimientos de EAA, el cálculo de los requerimientos de aminoácidos esenciales a partir de la concentración de aminoácidos del cuerpo -como se propone en este estudio- puede ser utilizado en la formulación de dietas para pámpano. Palabras clave: Carangidae, formulación de dietas, nutrición de peces, razón A/E. Resumo Antecedentes: estimar as necessidades por aminoácidos essenciais (AAE) é importante para formular dietas de boa qualidade e com bom custo-benefício. No entanto, poucas espécies de peixes possuem suas necessidades por (AAE) estabelecidas. A determinação das necessidades por (AAE) baseada na composição de aminoácidos do peixe é uma alternativa rápida e viável. Objetivo: determinar a composição de aminoácidos da carcaça e do músculo do Pampo prateado (Trachinotus marginatus) e estimar suas necessidades por (AAE). Métodos: as necessidades por AAE foi estimada usando o índice A/E [(AAE individual⁄AAE total) * 1000]. Resultados: histidina, leucina, lisina e fenilalanina estavam em maior concentração no músculo do que na carcaça. Por outro lado, arginina, isoleucina, metionina, triptofano e valina não apresentaram diferenças significativas entre a composição da carcaça e do músculo. O índice A/E determinado no presente estudo para o Pampo prateado é similar ao reportado para outras espécies de peixe, entretanto o valor do índice A/E para a valina foi ligeiramente menor. Conclusão: até que experimentos dose resposta sejam realizados para determinar com exatidão as necessidades por aminoácidos essenciais, os valores estimados para as necessidades por aminoácidos essenciais usando a composição da carcaça como proposto neste estudo pode ser usada na formulação de dietas para o Pampo prateado. Palavras chave: Carangidae, formulación de dietas, nutrição de peixes, razão A/E.

Effects of dietary protein and lipid levels on growth, feed utilization and body composition of juvenile swimming crab, Portunus trituberculatus

Abstract An 8-week feeding trial was conducted to determine the optimal dietary protein to energy (P/E) ratio for juvenile swimming crabs reared in cement pools. Nine practical diets were formulated to contain three protein levels (35%, 43% and 51%), each with three lipid levels (5%, 9% and 13%), to produce a range of P/E ratios from 17.70 to 26.89 g protein MJ− 1. Each diet was randomly assigned to triplicate groups of 60 juvenile swimming crabs (initial average weight about 3.75 ± 0.20 g) that were stocked in rectangle plastic baskets. The results of the present study indicated that weight gain, specific growth rate, protein efficiency ratio, protein retention and lipid retention were significantly influenced by the dietary protein and lipid levels, however, no significant differences in feed conversion ratio and survival were observed among all treatments. Crabs fed the diet with 51% protein and 5% lipid (P/E ratio of 26.89 mg protein kJ− 1) exhibited higher weight gain, specific growth rate and lipid retention than other diets. Moreover, the crabs fed the diets with the lowest protein level (35%) showed higher protein efficiency ratio and protein retention compared to the other diets containing higher protein levels (43% and 51% protein levels). The dietary protein and lipid levels (P/E ratios) had significant influences on the whole body crude protein, crude lipid, moisture contents and muscle amino acid profile; lipid content in the whole body significantly increased when the dietary lipid level increased from 5% to 13% at the same protein levels. There were no significant differences in the ash content of the whole body and muscle, and the crude lipid content in the muscle was not significantly affected by the dietary protein and lipid levels. Lysine, methionine, histidine and threonine of the muscle were significantly influenced by the dietary protein and lipid levels. Meanwhile, total protein, cholesterol and glucose concentrations in the serum were significantly affected by the dietary different protein and lipid levels. These results demonstrate that the diet containing 51% protein level and 5% lipid level with P/E of 26.89 mg protein kJ− 1 is optimal for juvenile swimming crab.

Amino acid δ13C analysis shows flexibility in the routing of dietary protein and lipids to the tissue of an omnivore.

Stable-isotope analysis (SIA) has revolutionized animal ecology by providing time-integrated estimates of the use of resources and/or habitats. SIA is based on the premise that the isotopic composition of a consumer's tissues originates from its food, but is offset by trophic-discrimination (enrichment) factors controlled by metabolic processes associated with the assimilation of nutrients and the biosynthesis of tissues. Laboratory preparation protocols dictate that tissues both of consumers and of their potential prey be lipid-extracted prior to analysis, because (1) lipids have carbon isotope (δ(13)C) values that are lower by approximately 3-8‰ than associated proteins and (2) amino acids in consumers' proteinaceous tissues are assumed to be completely routed from dietary protein. In contrast, models of stable-isotope mixing assume that dietary macromolecules are broken into their elemental constituents from which non-essential amino acids are resynthesized to build tissues. Here, we show that carbon from non-protein dietary macromolecules, namely lipids, was used to synthesize muscle tissue in an omnivorous rodent (Mus musculus). We traced the influence of dietary lipids on the synthesis of consumers' tissues by inversely varying the dietary proportion of C4-based lipids and C3-based protein while keeping carbohydrate content constant in four dietary treatments, and analyzing the δ(13)C values of amino acids in mouse muscle after 4 months of feeding. The influence of dietary lipids on non-essential amino acids varied as function of biosynthetic pathway. The source of carbon in ketogenic amino acids synthesized through the Krebs cycle was highly sensitive to dietary lipid content, with significant increases of approximately 2-4‰ in Glutamate and Aspartate δ(13)C values from the 5% to 15% dietary lipid treatment. Glucogenic amino acids (Glycine and Serine) were less sensitive to dietary lipid, but increased by approximately 3-4‰ from the 25% to 40% lipid diet. As expected, the δ(13)C values of essential amino acids did not vary significantly among diets. Although lipids provide a calorie-rich resource that fuels energy requirements, our results show that they also can be an important elemental source of carbon that contributes to the non-essential amino acids used to build structural tissue like muscle. As such, the calculation of trophic-discrimination factors for animals that consume a lipid-rich diet should consider lipid carbon as a building block for proteinaceous tissues. Careful consideration of the macromolecular composition in the diet of the consumer of interest will help to further refine the use of SIA to study animal ecology and physiology.

Fasting increases human skeletal muscle net phenylalanine release and this is associated with decreased mTOR signaling.

AimFasting is characterised by profound changes in energy metabolism including progressive loss of body proteins. The underlying mechanisms are however unknown and we therefore determined the effects of a 72-hour-fast on human skeletal muscle protein metabolism and activation of mammalian target of rapamycin (mTOR), a key regulator of cell growth.MethodsEight healthy male volunteers were studied twice: in the postabsorptive state and following 72 hours of fasting. Regional muscle amino acid kinetics was measured in the forearm using amino acid tracers. Signaling to protein synthesis and breakdown were assessed in skeletal muscle biopsies obtained during non-insulin and insulin stimulated conditions on both examination days.ResultsFasting significantly increased forearm net phenylalanine release and tended to decrease phenylalanine rate of disappearance. mTOR phosphorylation was decreased by ∼50% following fasting, together with reduced downstream phosphorylation of 4EBP1, ULK1 and rpS6. In addition, the insulin stimulated increase in mTOR and rpS6 phosphorylation was significantly reduced after fasting indicating insulin resistance in this part of the signaling pathway. Autophagy initiation is in part regulated by mTOR through ULK1 and fasting increased expression of the autophagic marker LC3B-II by ∼30%. p62 is degraded during autophagy but was increased by ∼10% during fasting making interpretation of autophagic flux problematic. MAFbx and MURF1 ubiquitin ligases remained unaltered after fasting indicating no change in protesomal protein degradation.ConclusionsOur results show that during fasting increased net phenylalanine release in skeletal muscle is associated to reduced mTOR activation and concomitant decreased downstream signaling to cell growth.

Correlation between body size and fatty acid and essential amino acid composition of round goby (Neogobius melanostomus) and monkey goby (Neogobius fluviatilis) from the Rhine River (Germany)

In this study correlations between body size and muscle fatty and amino acid content of two species of goby, round goby (Neogobius melanostomus) and monkey goby (Neogobius fluviatilis) caught from river Rhine (Germany) were investigated. Among saturated fatty acids (SFAs), mono- (MUFA) and polyunsaturated fatty acids (PUFAs) only SFAs were significantly higher in round goby than monkey goby (P < 0.05). In general, the correlation between body size of both gobies and the content of most of the individual fatty acids was not significant. In monkey goby, the content of palmitic acid (C16:0) and oleic acid (C18:1 n-9) was positively correlated with weight (r = 0.43) and total length (r = −0.58), respectively, and the content of docosahexaenoic acid (DHA) increased with condition factor (r = 0.50). The content of threonine, arginine, valine, phenylalanine and isoleucine in monkey goby was higher than those of round goby (P < 0.05). In round goby the three essential amino acids arginine, valine and leucine were positively (P < 0.05) correlated with body length, which indicates that longer round gobies are of higher nutritional value.

A Comparative Study on Lipid and Protein Composition of Oreochromis niloticus Muscles from Five Different Localities in Egypt

This study was aimed to compare the muscle lipid and protein composition of Oreochromis niloticus from five different localities in Egypt in order to determine the most nutritionally valuable samples based on the mode of feeding supplied. The fish samples were brought from the River Nile (natural feeding), Ismailia Canal (zooplankton feeding) and three fish aquacultures; Balteem (low protein diet, 18%), Al Abbasa (high protein diet, 30%) and Al Qanater Al Khaireya (zooplankton feeding in concrete tanks). Muscle total protein and total lipid contents were estimated. Fatty acid and amino acid analysis were carried out. Studying muscle protein fractions was undertaken using SDS-PAGE electrophoresis. Results showed that the highest total proteins content was detected in the River Nile sample, while the lowest was estimated in Al Qanater fish sample. The percentage value of essential amino acids in the fish muscles from Al Abbasa was higher (45.6%) than the other four localities. Total lipids were found to have the highest value in Al Abbasa aquaculture sample whereas the lowest level was detected in the River Nile sample. Analysis of fatty acids and amino acids revealed variable differences between all the examined samples from the five localities. Polyunsaturated fatty acid (PUFA) analysis showed that omega-3 had the highest % value in O. niloticus from the River Nile and Al Abbasa localities (30.30 and 30.36 respectively), while omega-6 fatty acids were higher in the fish samples from Balteem and Al Qanater (35.5% and 36.08% respectively) than the other fish samples. Elecrtophoretic data analysis showed that the highest number and percentage values of protein fractions among the five localities were recorded in sample obtained from the River Nile. It could be concluded that the best nutritional fish muscle quality was related to natural feeding in the River Nile sample and that fed on high protein diet at Al Abbasa aquaculture.

Evaluation of methods to estimate the essential amino acids requirements of fish bfrom the muscle amino acid profile

Many methods to estimate amino acid requirement based on amino acid profile of fish have been proposed. This study evaluates the methodology proposed by Meyer & Fracalossi (2005) and by Tacon (1989) to estimate amino acids requirement of fish, which do exempt knowledge on previous nutritional requirement of reference amino acid. Data on amino acid requirement of pacu, Piaractus mesopotamicus, were used to validate de accuracy of those methods. Meyer & Fracalossi's and Tacon's methodology estimated the lysine requirement of pacu, respectively, at 13 and 23% above requirement determined using dose-response method. The values estimated by both methods lie within the range of requirements determined for other omnivorous fish species, the Meyer & Fracalossi (2005) method showing better accuracy.

Herbicide Clomazone Effects on δ-Aminolevulinic Acid Activity and Metabolic Parameters in Cyprinus carpio

The objective of this study was to investigate δ-aminolevulinic acid (δ-ALA-D) activity and metabolic parameters of Cyprinus carpio exposed to clomazone herbicide. Fish were exposed 2.5, 5, 10 and 20 mg L(-1) of clomazone for 192 h. Results indicated that δ-ALA-D activity was decreased in the gills at concentrations of 5 and 10 mg L(-1). Liver glycogen increased, while muscle and gill glycogen levels decreased at 5, 10 and 20 mg L(-1). Glucose was increased in the gills and plasma. Lactate decreased in the gills and liver and increased in the muscle. Protein and amino acids levels increased in the liver and gills and decreased in the muscle. At a clomazone concentration of 20 mg L(-1), ammonia increased in the gills and muscle and decreased in the liver. The results indicated that the metabolic parameters of glycogen, lactate, protein and amino acids in liver, muscle and gills, blood glucose levels, and the enzyme δ-ALA-D in gills may be useful indicators of clomazone toxicity in carp.

Effects of fishmeal replacement with soy protein hydrolysates on growth performance, blood biochemistry, gastrointestinal digestion and muscle composition of juvenile starry flounder (Platichthys stellatus)

Abstract The nutritional value of soy protein can be improved by enzymatic modification into hydrolysates (SPH), which provide an alternative ingredient for replacing fishmeal protein (FMP) in feed. This study assessed the feasibility of replacing FMP with SPH in diet for juvenile starry flounder ( Platichthys stellatus Pallas). The changes in growth performance, blood biochemical indices, gastrointestinal enzyme activities, and muscle composition of fish were examined after 9 weeks of feeding with iso-energetic and iso-proteic diets, in which 0 (control), 15, 30, 50, 70, 85, and 100% of FMP were replaced by SPH (SPH0–100). Results showed that diets with low to moderate SPH inclusion levels (SPH15–50) significantly reduced feed conversion ratio and increased average body weight gain, weight gain ratio, specific growth ratio, daily feed intake, and protein efficiency ratio ( P P P P P P P P P > 0.05), but diets SPH15–70 significantly elevated trypsin activity ( P P P > 0.05), whereas the contents of aspartic acid, glutamic acid, serine, glycine, and total indispensable amino acids in muscle significantly declined in fish fed the diets SPH85–100 ( P

STIM1 Regulates Sarcoplasmic Reticulum CA2+-ATPase 1A (SERCA1a) in Skeletal Muscle

Stromal interaction molecule 1 (STIM1) mediates Ca2+ movements from the extracellular space to the cytosol through a store-operated Ca2+ entry(SOCE) mechanism in various cells including skeletal muscle cells. In the present study, to reveal the unidentified functional role of the STIM1 C-terminus from 449 to 671 amino acids in skeletal muscle, binding assays and quadrupole time-of-flight mass spectrometry were used to identify proteins binding in this region along with proteins that mediate skeletal muscle contraction and relaxation. STIM1 binds to sarcoplasmic/endoplasmic reticulum Ca2+-ATPase 1a (SERCA1a) via this region (called STIM1-SBR). The binding was confirmed in endogenous full-length STIM1 in rabbit skeletal muscle and mouse primary skeletal myotubes via co-immunoprecipitation assay and immunocytochemistry. STIM1-knockdown in mouse primary skeletal myotubes decreased Ca2+-uptake from the cytosol to the sarcoplasmic reticulum (SR) through SERCA1a only at micromolar cytosolic Ca2+ concentrations, suggesting that STIM1 could be required for the full activity of SERCA1a possibly during the relaxation of skeletal muscle. Various Ca2+ imaging experiments using myotubes expressing STIM1-SBR suggest that STIM1 is involved in intracellular Ca2+ distributions between the SR and the cytosol via regulating SERCA1a activity without affecting SOCE. Therefore, in skeletal muscle, STIM1 could play an important role in regulating Ca2+ movements between the SR and the cytosol.

Branched-chain amino acid-rich diet improves skeletal muscle wasting caused by cigarette smoke in rats

Cigarette smoke induces skeletal muscle wasting by a mechanism not yet fully elucidated. Branched-chain amino acids (BCAA) in the skeletal muscles are useful energy sources during exercise or systemic stresses. We investigated the relationship between skeletal muscle wasting caused by cigarette smoke and changes in BCAA levels in the plasma and skeletal muscles of rats. Furthermore, the effects of BCAA-rich diet on muscle wasting caused by cigarette smoke were also investigated. Wistar Kyoto (WKY) rats that were fed with a control or a BCAA-rich diet were exposed to cigarette smoke for four weeks. After the exposure, the skeletal muscle weight and BCAA levels in plasma and the skeletal muscles were measured. Cigarette smoke significantly decreased the skeletal muscle weight and BCAA levels in both plasma and skeletal muscles, while a BCAA-rich diet increased the skeletal muscle weight and BCAA levels in both plasma and skeletal muscles that had decreased by cigarette smoke exposure. In conclusion, skeletal muscle wasting caused by cigarette smoke was related to the decrease of BCAA levels in the skeletal muscles, while a BCAA-rich diet may improve cases of cigarette smoke-induced skeletal muscle wasting.