Muscle Amino Acid Research Articles

Regulation of Skeletal Muscle Function by Amino Acids

Amino acids are components of proteins that also exist free-form in the body; their functions can be divided into (1) nutritional, (2) sensory, and (3) biological regulatory roles. The skeletal muscle, which is the largest organ in the human body, representing ~40% of the total body weight, plays important roles in exercise, energy expenditure, and glucose/amino acid usage—processes that are modulated by various amino acids and their metabolites. In this review, we address the metabolism and function of amino acids in the skeletal muscle. The expression of PGC1α, a transcriptional coactivator, is increased in the skeletal muscle during exercise. PGC1α activates branched-chain amino acid (BCAA) metabolism and is used for energy in the tricarboxylic acid (TCA) cycle. Leucine, a BCAA, and its metabolite, β-hydroxy-β-methylbutyrate (HMB), both activate mammalian target of rapamycin complex 1 (mTORC1) and increase protein synthesis, but the mechanisms of activation appear to be different. The metabolite of valine (another BCAA), β-aminoisobutyric acid (BAIBA), is increased by exercise, is secreted by the skeletal muscle, and acts on other tissues, such as white adipose tissue, to increase energy expenditure. In addition, several amino acid-related molecules reportedly activate skeletal muscle function. Oral 5-aminolevulinic acid (ALA) supplementation can protect against mild hyperglycemia and help prevent type 2 diabetes. β-alanine levels are decreased in the skeletal muscles of aged mice. β-alanine supplementation increased the physical performance and improved the executive function induced by endurance exercise in middle-aged individuals. Further studies focusing on the effects of amino acids and their metabolites on skeletal muscle function will provide data essential for the production of food supplements for older adults, athletes, and individuals with metabolic diseases.

Effect of L-theanine on meat quality, muscle amino acid profiles, and antioxidant status of broilers.

This study investigated the effect of L-theanine on carcass traits, meat quality, muscle antioxidant capacity, and amino acid (AA) profiles of broilers. Three hundred 1-day-old Ross 308 male broilers were randomly allotted to five groups with six replicates. Birds were fed the basal diet or basal diet with 300, 600, 900, or 1,500mg/kg L-theanine for 42 consecutive days. The results showed that L-theanine quadratically increased dressing percentage, eviscerated percentage, and leg muscle yield (p<.05). Meanwhile, drip loss, cooking loss, shear force, L*24h, and muscle lactate content decreased quadratically in response to dietary L-theanine supplementation (p<.05), while pH24h and muscle glycogen content were quadratically improved by L-theanine (p<.05). Notably, the contents of muscle malondialdehyde and protein carbonyl, and the activities of muscle total antioxidant capacity, catalase, and glutathione peroxidase decreased quadratically in response to dietary L-theanine supplementation (p<.05), suggesting that the oxidative stress level of muscle was decreased quadratically. Moreover, L-theanine quadratically increased the concentrations of most of muscle essential AA, nonessential AA, and flavor AA (p<.05). In conclusion, L-theanine can be used as a valuable feed additive to modulate carcass traits, meat quality, muscle antioxidant status, and AA profiles of boilers, and its optimum addition level is 600mg/kg based on the present study.

Fishmeal can be replaced with a high proportion of terrestrial protein in the diet of the carnivorous marine teleost (Trachinotus ovatus)

In general, over 30% fishmeal (FM) is required in diets for marine teleosts, which limits the sustainable development of aquaculture. Here, seven isonitrogenous (46%) and isolipidic (12%) diets (namely D1-D7) were formulated with three compound proteins (CPro I, CPro II and CPro III), which consisted of terrestrial animal and plant proteins, as substitutes for FM. Diet D1 (control) contained 30% FM, while diets D2-D3, D4-D5 and D6-D7 were formed by replacing 40% and 60%, 40% and 60%, and 60% and 80% FM with CPro I, CPro II, and CPro III, respectively. Juveniles of the carnivorous marine teleost Trachinotus ovatus were fed the seven diets in floating sea cages for 8 weeks. Growth performance including weight gain (WG) and specific growth rate (SGR), serum biochemical indices alkaline phosphatase (AKP) and glutamic pyruvate transaminase (GPT) activities, serum and liver antioxidant indices catalase (CAT) activities and total antioxidant capacity (T-AOC), fish proximate composition, muscle cooking percentage (CP) and textural properties of fish fed diets D2-D7 showed no difference or improved values compared with those of fish fed diet D1, suggesting no negative effects produced with 40–80% replacement of dietary FM by the compound proteins. Significantly higher contents of essential amino acids (EAA), non-essential amino acids (NEAA) and flavour amino acids (FAA) in muscle, as well as higher liver antioxidant capacity were found in fish fed diets D6 (12% FM) or D7 (6% FM) compared with those fed diet D1. The results demonstrated that 40–80% replacement of dietary FM by terrestrial compound proteins is feasible in T. ovatus, moreover 60% or 80% replacement brought a positive influence on antioxidant capacity and nutritional value.

50 Years Ago in TheJournal ofPediatrics: Cerebral Gigantism: Concentrations of Amino Acids in Plasma and Muscle

50 Years Ago in TheJournal ofPediatrics: Cerebral Gigantism: Concentrations of Amino Acids in Plasma and Muscle

Histological Distribution and Characterization of Collagen in European eel (Anguilla anguilla) Muscle

ABSTRACTThe histologic structure of eel muscle was observed, and the acid solubilized collagen (ASC) and pepsin solubilized collagen (PSC) from eel muscle were prepared and examined. The collagenous fiber amount in both head and tail seemed to be higher than that in the trunk. The Glu, Asp, Arg, Ala, Leu, and Lys contents accounted for about 54% of total amino acids in the eel muscle. There were no significant differences in the amino acid composition and ultraviolet spectra between ASC and PSC. The molecular weights of α1 subunit in both collagens were 129 and 123 kDa, respectively; but their molecular weights of α2 subunit were 113 kDa. According to peptide mapping analysis, it was found that there were obvious differences in primary structures between ASC and PSC. The amide A band positions of ASC and PSC appeared at 3320 cm−1 and 3312 cm−1 of Fourier transform infrared spectra, respectively. No obvious difference was found in the thermal stability of both collagens, probably due to the synergistic effect of molecular weight and hydrogen bonds.

PSIX-22 Effects of betaine supplementation on growth performance, muscle amino acid contents, meat quality and antioxidant capacity in finishing pigs

Abstract The aim of this study was to investigate the effects of betaine supplementation on growth performance, muscle amino acid contents, meat quality and antioxidant capacity in finishing pigs. A total of 144 crossbred barrows (Duroc×Landrace×Yorkshire) weighing about 69 kg were divided into three groups with six replicates of eight pigs each for a 60-day feeding trial. Pigs were fed a maize-soybean meal basal diet supplemented with 0 (control), 1 or 1.5 g/kg betaine, respectively. Data were analyzed by one-way ANOVA using SPSS software, and the differences among treatments were examined by Tukey’s test, which were considered to be significant at P &amp;lt; 0.05. The results showed that the feed conversion ratio tended to be improved (P = 0.081) by betaine supplementation. Compared with the control, 1.5 g/kg betaine supplementation significantly increased (P &amp;lt; 0.05) the contents of methionine, glutamate and total non-essential amino acid in thigh muscle, but the amino acid contents in loin muscle were not affected by betaine supplementation. The 24-h and 48-h drip loss of thigh muscle and the content of malondialdehyde in loin muscle were decreased (P &amp;lt; 0.05) by 1 g/kg betaine inclusion, and the 24-h redness values of loin and thigh muscles were increased (P &amp;lt; 0.05) by 1.5 g/kg betaine inclusion. Moreover, both levels of betaine significantly increased (P &amp;lt; 0.05) 24-h pH value and the activity of total superoxide dismutase of loin and thigh muscles. Overall, this study indicated that 1.5 g/kg betaine supplementation could increase the contents of methionine, glutamate and total non-essential amino acid in thigh muscle rather than loin muscle, and betaine supplementation was beneficial to improve meat quality and antioxidant capacity in finishing pigs. 1SEM, total standard error of means (n = 6)

High Altitude Adaptability and Meat Quality in Tibetan Pigs: A Reference for Local Pork Processing and Genetic Improvement.

Simple SummaryThe increase in altitude will bring about a complex change in a series of elements of nature, which will have a profound impact on human production and life. Studying domestic animals in the native environment is an effective way to explore the impact of high altitude on human life, and at the same time is conducive to the development of local animal husbandry. Here, we found that the hypoxic adaptation of Tibetan pigs may be related to higher levels of VEGFA, HIF1 and myoglobin expression. The higher aerobic oxidative capacity of Tibetan pigs is beneficial to improve energy utilization, and the higher UFA content of Tibetan pigs is beneficial to cold resistance. In addition, Tibetan pigs have higher levels of BCAA and Myh2 expression, which serve to relieve muscle fatigue and improve endurance. In addition, it was observed that there are obvious differences in carcass and meat quality traits of different altitudes pigs. Taken together, our findings illustrate the adaptability of Tibetan pigs to high altitude from various perspectives and compare carcass and meat quality traits of three pig breeds.The carcass and meat quality traits of pig breeds living at three different altitudes (Yorkshire pigs, YP: 500m; Qingyu Pigs, QYP: 1500m; Tibetan pigs, TP: 2500m) were compared. It was observed that there are obvious differences in pig breeds with respect to performance parameters. Specifically, YP had the best carcass traits, showing high slaughter rates and leanest meat. Conversely, QYP had the highest back fat thickness and intramuscular fat (IMF) content. For the high-altitude breed TP, the animals exhibited low L* and high a* values. The genotypes contributing to the observed phenotypes were supported by a PCR analysis. The glycolytic genes expression (HK, PFK, PK) were highest in YP, whereas expression of genes related to adipogenesis (C/EBPα, FABP4, SCD1) were highest in QYP. As expected, genes associated with angiogenesis and hypoxia (HIF1a, VEGFA) were expressed at the highest levels in TP. The composition and proportion of amino and fatty acids in pig muscles at the three altitudes examined also varied substantially. Among the breeds, TP had the highest proportion of umami amino acids, whereas QYP had the highest proportion of sweet amino acids. However, TP also exhibited the highest proportion of essential fatty acids and the lowest proportion of n6:n3. This study explains the high-altitude adaptive evolution and the formation of meat quality differences in different altitude pigs from various angles and provides a reference for local pork food processing and genetic improvement of local pigs.

Proteomic and Transcriptomic Changes in Hibernating Grizzly Bears Reveal Metabolic and Signaling Pathways that Protect against Muscle Atrophy

Muscle atrophy is a physiological response to disuse and malnutrition, but hibernating bears are largely resistant to this phenomenon. Unlike other mammals, they efficiently reabsorb amino acids from urine, periodically activate muscle contraction, and their adipocytes differentially responds to insulin. The contribution of myocytes to the reduced atrophy remains largely unknown. Here we show how metabolism and atrophy signaling are regulated in skeletal muscle of hibernating grizzly bear. Metabolic modeling of proteomic changes suggests an autonomous increase of non-essential amino acids (NEAA) in muscle and treatment of differentiated myoblasts with NEAA is sufficient to induce hypertrophy. Our comparison of gene expression in hibernation versus muscle atrophy identified several genes differentially regulated during hibernation, including Pdk4 and Serpinf1. Their trophic effects extend to myoblasts from non-hibernating species (including C. elegans), as documented by a knockdown approach. Together, these changes reflect evolutionary favored adaptations that, once translated to the clinics, could help improve atrophy treatment.

The amino acid profile after addition of humic acids and phytobiotics into diet of broiler chicken

The aim of the study was analysed the effect of humic acids separately and humic acids in combination with phytobiotic as garlic and oregano powder on amino acid (AA) profile of the most valuable parts of Ross 308 chicken. A total of 200 pcs Ross 308 broiler chickens of mixed sex were randomly divided into 4 groups (n=50): control group (C) without supplementation, experiment group E1 (2% humic acids), E2 (80% humic acids and 20% garlic powder) and E3 (90% humic acids and 10% oregano powder). Fattening period lasted for 42 days and all groups were kept under the same conditions. After slaughter, the AA profiles of breast and thigh samples were determined. In comparison with control group, 6 out of 10 AA was significantly affected (p ≤0.05) by used dietary supplementation - Met, Cys and His in thigh and Leu, Phe, His and Arg in breast muscle. AA composition of breast muscle was positively affected mainly by humic acids and 10% oregano powder supplementation (E3), while thigh muscle by humic acids and 20% garlic powder (E2). The highest obtained AA in breast muscle was Leu (2.02 g.100 g-1) in E3 group and thigh muscle His (1.15 g.100 g-1) in E2 group (p ≤0.05). In conclusion, humic acids and 10% oregano powder supplementation (E3) elicited to the best AA profile of chicken breast muscle but also the worst AA profile in thigh muscle so the effect of such a supplementation is disputable. On the other hand, humic acids and 20% garlic powder supplementation resulted into slight increase of AA in both breast and thigh muscle (E2).

Derangements of amino acids in cachectic skeletal muscle are caused by mitochondrial dysfunction.

BackgroundCachexia is the direct cause of at least 20% of cancer‐associated deaths. Muscle wasting in skeletal muscle results in weakness, immobility, and death secondary to impaired respiratory muscle function. Muscle proteins are massively degraded in cachexia; nevertheless, the molecular mechanisms related to this process are poorly understood. Previous studies have reported conflicting results regarding the amino acid abundances in cachectic skeletal muscle tissues. There is a clear need to identify the molecular processes of muscle metabolism in the context of cachexia, especially how different types of molecules are involved in the muscle wasting process.MethodsNew in situ ‐omics techniques were used to produce a more comprehensive picture of amino acid metabolism in cachectic muscles by determining the quantities of amino acids, proteins, and cellular metabolites. Using matrix‐assisted laser desorption/ionization (MALDI) mass spectrometry imaging, we determined the in situ concentrations of amino acids and proteins, as well as energy and other cellular metabolites, in skeletal muscle tissues from genetic mouse cancer models (n = 21) and from patients with cancer (n = 6). Combined results from three individual MALDI mass spectrometry imaging methods were obtained and interpreted. Immunohistochemistry staining for mitochondrial proteins and myosin heavy chain expression, digital image analysis, and transmission electron microscopy complemented the MALDI mass spectrometry imaging results.ResultsMetabolic derangements in cachectic mouse muscle tissues were detected, with significantly increased quantities of lysine, arginine, proline, and tyrosine (P = 0.0037, P = 0.0048, P = 0.0430, and P = 0.0357, respectively) and significantly reduced quantities of glutamate and aspartate (P = 0.0008 and P = 0.0124). Human skeletal muscle tissues revealed similar tendencies. A majority of altered amino acids were released by the breakdown of proteins involved in oxidative phosphorylation. Decreased energy charge was observed in cachectic muscle tissues (P = 0.0101), which was related to the breakdown of specific proteins. Additionally, expression of the cationic amino acid transporter CAT1 was significantly decreased in the mitochondria of cachectic mouse muscles (P = 0.0133); this decrease may play an important role in the alterations of cationic amino acid metabolism and decreased quantity of glutamate observed in cachexia.ConclusionsOur results suggest that mitochondrial dysfunction has a substantial influence on amino acid metabolism in cachectic skeletal muscles, which appears to be triggered by diminished CAT1 expression, as well as the degradation of mitochondrial proteins. These findings provide new insights into the pathobiochemistry of muscle wasting.

GLUTATHIONE, MITOCHONDRIAL DEFECTS, AND A UNIQUE METABOLIC CYCLE IN OLDER HUMANS: IMPLICATIONS FOR SARCOPENIA

Sarcopenia in aging leads to decreased muscle mass and physical-function (muscle strength and exercise capacity), but underlying mechanisms are not well understood and effective interventions are limited. We hypothesized that deficiency of the intracellular antioxidant protein Glutathione initiates a unique self-perpetuating metabolic cycle linking impaired fasted mitochondrial fuel-oxidation (fMFO) to protein catabolism and contributes to sarcopenia. We also hypothesized that supplementing the Glutathione precursor amino-acids glycine and N-acetylcysteine (GlyNAC) to correct Glutathione deficiency in older humans could reverse these defects. We tested our hypothesis in a 24-week open-label clinical-trial in 8 older-humans (74y) studied before and 24-weeks after GlyNAC supplementation, compared to 8 gender-matched unsupplemented young-controls (25y), and measured intracellular Glutathione concentrations, fMFO, physical-function, muscle-protein breakdown-rate (MPBR), gluconeogenesis, and urine nitrogen-excretion (UNE). GlyNAC supplementation in older humans corrected Glutathione deficiency and restored impaired fMFO (to levels in young controls), lowered MPBR and UNE, and increased physical-function, but did not affect gluconeogenesis or increase lean-mass, and suggest that muscle amino-acids are utilized for energy needs rather than glucose production. The absence of an increase in lean-mass suggests that GlyNAC should be combined with anabolic agents for potential benefits in combating sarcopenia. Overall, these results indicate the presence of a unique reversible metabolic cycle in older humans initiated by Glutathione deficiency which results in impaired mitochondrial fatty-acid and glucose oxidation, muscle-protein breakdown, UNE, and leads to deficiency of glycine and cysteine which re-initiate the cycle. These data have implications for improving physical-function and muscle mass in age-associated sarcopenia, and warrants further investigation.

Effects of histidine load on ammonia, amino acid, and adenine nucleotide concentrations in rats.

The unique capability of proton buffering is the rationale for using histidine (HIS) as a component of solutions for induction of cardiac arrest and myocardial protection in cardiac surgery. In humans, infusion of cardioplegic solution may increase blood plasma HIS from ~ 70 to ~ 21,000µM. We examined the effects of a large intravenous dose of HIS on ammonia and amino acid concentrations and energy status of the body. Rats received 198mM HIS intravenously (20ml/kg) or vehicle. Samples of blood plasma, urine, liver, and soleus (SOL) and extensor digitorum longus (EDL) muscles were analysed at 2 or 24h after treatment. At 2h after HIS load, we found higher HIS concentration in all examined tissues, higher urea and ammonia concentrations in blood and urine, lower ATP content and higher AMP/ATP ratio in the liver and muscles, higher concentrations of almost all examined amino acids in urine, and lower glycine concentration in blood plasma, liver, and muscles when compared with controls. Changes in other amino acids were tissue dependent, markedly increased alanine and glutamate in the blood and the liver. At 24h, the main findings were lower ATP concentrations in muscles, lower concentrations of branched-chain amino acids (BCAA; valine, leucine, and isoleucine) in blood plasma and muscles, and higher carnosine content in SOL when compared with controls. It is concluded that a load of large HIS dose results in increased ammonia levels and marked alterations in amino acid and energy metabolism. Pathogenesis is discussed in the article.

Optimizing diets to decrease environmental impact of Nile tilapia (Oreochromis niloticus) production

Aquaculture is one of the most thriving animal production sectors, and Nile tilapia (Oreochromis niloticus) farming represents 8% of total finfish culture. However, the industry sustainability depends on the development of cost-effective and environmental friendly feeds. This study aimed to reduce dietary protein levels in diets for juvenile tilapia and to minimize diet environmental impact while maximizing biological efficiency. A growth trial was performed using five isoenergetic plant protein-based diets with decreasing levels of crude protein: 360, 340, 320, 300 and 280 g/kg diet (D360, D340, D320, D300 and D280, respectively). Dietary protein utilization was assessed by metabolic trials using a radiolabelled amino acid mixture. Tilapia in all treatments showed similar growth performance and feed intake. Feed conversion ratio was significantly higher in fish fed the D280 than the D360 diet, while no differences were found for other treatments. Protein retention was significantly higher in tilapia fed the D300 than the D360 diet. Amino acid catabolism increased in fish fed the D360 diet, though without significant differences in muscle amino acid retention. This study demonstrates that dietary protein levels can be reduced to 300 g/kg diet without hindering tilapia growth and feed conversion ratio, while reducing environmental nitrogen losses.

Skeletal muscle amino acid uptake is lower and alanine production is greater in late gestation intrauterine growth-restricted fetal sheep hindlimb.

In a sheep model of intrauterine growth restriction (IUGR) produced from placental insufficiency, late gestation fetuses had smaller skeletal muscle mass, myofiber area, and slower muscle protein accretion rates compared with normally growing fetuses. We hypothesized that IUGR fetal muscle develops adaptations that divert amino acids (AAs) from protein accretion and activate pathways that conserve substrates for other organs. We placed hindlimb arterial and venous catheters into late gestation IUGR (n = 10) and control (CON, n = 8) fetal sheep and included an external iliac artery flow probe to measure hindlimb AA uptake rates. Arterial and venous plasma samples and biceps femoris muscle were analyzed by mass spectrometry-based metabolomics. IUGR fetuses had greater abundance of metabolites enriched within the alanine, aspartate, and glutamate metabolism pathway compared with CON. Net uptake rates of branched-chain AA (BCAA) were lower by 42%-73%, and muscle ammoniagenic AAs (alanine, glycine, and glutamine) were lower by 107%-158% in IUGR hindlimbs versus CON. AA uptake rates correlated with hindlimb weight; the smallest hindlimbs showed net release of ammoniagenic AAs. Gene expression levels indicated a decrease in BCAA catabolism in IUGR muscle. Plasma purines were lower and plasma uric acid was higher in IUGR versus CON, possibly a reflection of ATP conservation. We conclude that IUGR skeletal muscle has lower BCAA uptake and develops adaptations that divert AAs away from protein accretion into alternative pathways that sustain global energy production and nitrogen disposal in the form of ammoniagenic AAs for metabolism in other organs.

Different biochemical composition and nutritional value attribute to salinity and rearing period in male and female mud crab Scylla paramamosain

Crabs show major differences in biochemical composition and nutritional value responding to various culture environments, growth stages and even sexes. In the present study, juvenile mud crab Scylla paramamosain (0.026 ± 0.010 g) were cultured at two earthen ponds with the respective salinity level of 25‰ and 5‰ for four months. The proximate composition, amino acid content and fatty acid profile in edible parts (muscle and hepatopancreas) of male and female crabs reared at different salinities and two rearing periods (three-month stage: 60–120 g and four-month stage: 150–300 g) were investigated and compared. Crabs at high salinity had significantly lower moisture contents in muscle and hepatopancreas, but had higher protein contents in muscle and higher ratio of n-3/n-6 highly unsaturated fatty acids (PUFA) in both edible parts, regardless of gender and rearing period. Additionally, significant differences in biochemical composition and nutritional value were also found between male and female crabs. For example, the contents of crude protein and most amino acids were higher in muscle and hepatopancreas of females, whereas males contained higher n-3 PUFA contents in both edible parts. Further, the contents of delicious amino acids (DAA) and essential amino acids (EAA) in muscle and the crude lipid content in hepatopancreas exhibited a higher trend at three-month stage than that at four-month stage. The results suggested that S. paramamosain reared at high salinity had better nutritional value than that at low salinity, while female and male crabs possess their respective advantages in terms of different nutritional composition. In addition, crabs had a better nutritional quality at three-month stage, even though they were at a smaller size.

Genotype and dietary lysine deficiency affect carcass and muscle amino acid composition of pigs growing from 10 to 25 kg body weight.

Amino acid (AA) composition of body protein is considered constant although there are evidences that AA pattern in pigs may be altered by different factors. Pigs with different body composition and protein deposition rates-like fatty and lean pigs-may differ in AA composition, with possible consequences on their AA requirements. This work investigates effects of genotype and dietary lysine deficiency on AA composition of carcass and muscles of Iberian and Landrace×Large White pigs. Twenty-eight barrows (10kg body weight [BW]), 14 from each breed, were used. They were randomly assigned to two experimental diets according to a factorial arrangement (two breeds×two diets). Diets were isonitrogenous and isoenergetic (200±1g CP/kg dry matter (DM); 14.7±0.1MJ ME/kg DM) and with identical chemical composition except for lysine concentration (10.9 and 5.20g lysine/kg DM, for lysine-adequate (AL) diet and lysine-deficient (DL) diet respectively). Pigs were individually housed, and daily feed allowance was adjusted on a weekly basis according to BW. Pigs were slaughtered at 25kg BW. Isoleucine, valine and phenylalanine concentration were higher in carcass protein of Iberian pigs (p<.01). In longissimus muscle, higher concentration of arginine, isoleucine, phenylalanine, lysine and valine (p<.001-p<.05), and lower of methionine (p<.001) were detected in Iberian pigs, whereas phenylalanine, leucine, lysine, threonine and methionine concentration decreased and arginine increased (p<.001-p<.05) when pigs were fed DL diet. Genotype and lysine deficiency effects were moderate in the AA composition of protein of biceps femoris muscle. The results show that AA proportions in protein of carcass and longissimus muscle can be influenced by pig genotype and conditions of lysine shortage. The biceps femoris muscle, with different functional and metabolic properties, shows more constant AA composition than longissimus, which seem to prevail independent from genotype or nutritional challenges.

Effects of dietary curcumin and acetylsalicylic acid supplements on performance, muscle amino acid and fatty acid profiles, antioxidant biomarkers and blood chemistry of heat-stressed broiler chickens.

The objective was to investigate the effects of dietary curcumin and acetylsalicylic acid (ASA) on the performance and physiological responses of broiler chickens under chronic thermal stress. One hundred and sixty day-old male chicks (Ross 308) were divided equally into 4 groups (each contained 4 replicates). On the day 22 of age and thereafter, the first group (TN) was raised in a thermoneutral condition (23 ± 1 °C), while the second group (HS) was subjected to 8 h of thermal stress (34 °C) and both groups fed the basal diet with no supplements. The third (CR) and fourth (AS) groups were subjected to the same thermal stress conditions and fed curcumin-supplemented diet (100 mg curcumin kg-1 diet) and ASA-supplemented diet (1 g ASA kg-1 diet), respectively. Dietary treatment had a significant effect on ADFI (P = 0.041), average daily gain (P = 0.013) and final body weight (P = 0.001). The curcumin-supplemented had higher values for these measures compared with other experimental groups (P < 0.05). Also, the dietary curcumin supplement significantly increased the carcass yield as compared to the HS group (P < 0.05). Compared with the HS group, the dietary curcumin and ASA supplements decreased the concentration of malondialdehyde in the breast muscles (P = 0.014). Both dietary supplements exhibited a marked ability to restore the serum TAC, Na and K in heat-stressed broiler chickens. The current study reported a remarkable ability of curcumin supplement to restore the concentrations of polyunsaturated fatty acids (PUFA) in the breast muscles of heat-stressed broilers, including α-linolinec acid and Docosahexaenoic acid (P = 0.009 and 0.001, respectively). It could be concluded that supplemental dietary curcumin or ASA enhanced growth performance and antioxidant biomarkers of heat-stressed broilers. Moreover, curcumin might be an effective dietary supplement to alleviate the adverse effect of chronic thermal stress on carcass yield and meat quality.

Responses of chemical composition, amino acid and fatty acid profiles of breast muscle to dietary crude fibre levels in China Micro-Ducks

The effects of dietary crude fibre (CF) levels on the chemical composition, amino acid (AA) and fatty acid (FA) profiles of breast muscle in male China Micro-ducks (21 - 56 d) were investigated in this study. The birds were randomly allocated to four treatments, of which dietary CF levels were 16.7, 42.6, 77.9 and 101.6 g/kg of dry matter (DM), respectively. No influences on the proportions of crude ash, crude protein, lysine, methionine, threonine, phenylalanine, histidine, arginine, aspartic acid, glutamic acid, glycine, alanine, serine, cysteine, tyrosine, proline, C12:0, C18:0, C18:1n9, C20:0 and C22:1n9 in muscle were observed across the treatments. Consequently, the concentrations of semi-essential AA, non-essential AA, total AA, aromatic AA and delicious AA in muscle, along with the Δ-9-desaturase (18) index, were not affected by the treatments. Significant lower concentrations of valine, leucine, isoleucine, essential AA, branched-chain AA, C16:1n7 and monounsaturated FA in muscle, along with a lower ratio of branched-chain to aromatic AA, were noted in a dietary treatment with a CF level of 16.7 g/kg DM compared to other dietary treatments. The rise of the dietary CF level significantly increased the proportions of DM, ether extract, gross energy, C18:2n6, C18:3n3, C20:4n6, unsaturated FA, total FA, polyunsaturated FA, n-3 polyunsaturated FA, n-6 polyunsaturated FA, essential FA, and the Δ-9-desaturase (16) index. Furthermore, the rise of the dietary CF level increased the ratios of unsaturated to saturated FA, polyunsaturated to saturated FA, and n-6 to n-3 polyunsaturated FA in muscle. However, it decreased the atherogenic index and the proportions of C14:0, C16:0, and saturated FA significantly. In conclusion, depending largely on dietary levels, CF profoundly and positively influenced the nutritional quality of breast muscle, especially the FA profile. Keywords: China Micro-duck, dietary fibre, fatty acid, nutritional quality of meat, fatty acid

ВПЛИВ ІОНІВ МАНГАНУ, ЦИНКУ, КУПРУМУ ТА ПЛЮМБУМУ НА ВМІСТ ВІЛЬНИХ АМІНОКИСЛОТ В ОРГАНІЗМІ КОРОПА

The influence of ions of Manganese, Zinc, Copper and Lead in two concentrations, which corresponded to 2 and 5 MPC, on the content of free amino acids in the carp organism was studied. It is shown, that free amino acids are compounds, that are actively used in the energy supply of fish organisms. Their metabolism is one of the factors, that provides biochemical adaptation of fish to the changes of the conditions in the aquatic environment. The leading role in this process in carp organism have glycine, the content of which in the muscles of the control fish is quite high. It exceeds all other concentrations of amino acids in this tissue, and when exposed to the organism of fish, the ions of the investigated metals decreases to the greatest extent. Among other amino acids, it should be noted the growth both in the muscles and in the liver of experimental fish the amount of sulfur-containing. An important role in the detoxification of ammonia, which is formed under the influence on the organism of carp the elevated metal concentrations, belongs to aspartic and glutamic acids. In our studies, the content of free amino acids in the liver and muscle of fish is reduced by the action of metal ions, which may indicate an active involvement of aspartic and glutamic acid in the processes of detoxification of these ions. In general, the dynamics of free amino acids in carp tissues reflects the general tendencies of metabolism in its organism. Oxidation catabolism of amino acids of skeletal muscle and liver of fish is an important part of the integral physiological and biochemical mechanism, which provides energy homeostasis in their organism in conditions of intoxication.

Effects of dietary supplementation with betaine on muscle growth, muscle amino acid contents and meat quality in Cherry Valley ducks.

The effects of dietary betaine supplementationon growth performance, carcass characteristics, muscle amino acid contents, meat quality, antioxidant capacity, myogenic gene expression and mechanistic target of rapamycin (mTOR) signalling pathway in Cherry Valley ducks were evaluated. A total of 720 1-day-old Cherry Valley ducks were randomly distributed into four groups with six replicates of 30 birds for a 42-day feeding trial. Ducks were fed a basal diet supplemented with 0 (control), 250, 500 or 1,000mg/kg betaine, respectively. Growth performance was not affected by betaine. Incremental levels of betaine linearly (p<0.05) increased the breast muscle yield and linearly (p<0.05) decreased the subcutaneous fat thickness and the abdominal fat yield. The contents of methionine, serine, glycine, glutamate and total non-essential amino acid in breast muscle were linearly (p<0.05) increased by betaine supplementation. With increasing betaine levels, the drip loss and the content of malondialdehyde (MDA) were linearly (p<0.05) decreased, and the redness of meat (linear p<0.05), the activities of catalase (CAT) (linear p<0.05) and total superoxide dismutase (T-SOD) (linear p<0.05, quadratic p<0.05) were increased. Moreover, the myogenic differentiation factor 1 (MyoD1) mRNA expression and the mTOR mRNA expression and protein phosporylation were linearly (p<0.05) up-regulated, and the myostatin (MSTN) mRNA expression was linearly (p<0.05) down-regulatedby betaine supplementation. Overall, this study indicated that betaine supplementation did not affect the growth performance of Cherry Valley ducks, but could linearly increase some amino acid contents in breast muscle, especially glycine, and increase muscle antioxidant activity to improve meat quality. Moreover, betaine supplementation could improve the breast muscle yield by increasing MyoD1 mRNA expression, decreasing MSTN mRNA expression and regulating mTOR signalling pathway.