DIGESTION IN THE RUMEN AND AMINO ACID SUPPLY TO THE DUODENUM OF SHEEP FED ENSILED AND FRESH ALFALFA

1986 ◽  
Vol 66 (4) ◽  
pp. 1019-1027 ◽  
Author(s):  
D. A. FLORES ◽  
L. E. PHILLIP ◽  
D. M. VEIRA ◽  
M. IVAN
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Rumen Fluid ◽  
Essential Amino Acids ◽  
Ruminal Ph ◽  
Sheep Rumen ◽  
Branched Chain ◽  
High Degree ◽  
The Relationship ◽  
Adaptation Phase

A study was conducted with six sheep equipped with rumen and duodenal re-entrant cannulae to investigate differences in duodenal amino acid supply with fresh and ensiled alfalfa. The experiment was conducted as a cross-over design with two 12-d periods consisting of an adaptation phase (5 d) followed by feces collection (5 d), and finally on day 12, 24 h continuous collection of duodenal digesta and sampling of rumen fluid. During the experiment the sheep were restricted on feed to 52 g DM d−1 kg−0.75. Analyses of the forages revealed extensive breakdown of threonine, lysine and other basic amino acids, and high degree of preservation of branched chain amino acids. Relative to the amount consumed, there was a net loss of amino acids at the duodenum with fresh alfalfa but a net gain with silage. The relationship between intake of individual essential amino acids and duodenal recovery was inconsistent. Duodenal recovery of total essential amino acids was 28% higher with fresh than with ensiled alfalfa, a difference which was most pronounced with threonine and lysine. Digestion of organic matter and fiber was unaffected (P > 0.05) by ensiling of alfalfa. Estimates of ruminal pH were higher (P < 0.05) for silage than fresh forage (6.9 vs. 6.7) but VFA concentrations were lower (P < 0.05) for silage (52.1 vs. 64.1 mmol L−1). Rumen ammonia levels were similar for the two forages. The deficit in duodenal supply of essential amino acids with silage is discussed in relation to the problem of silage intake in ruminants. Key words: Alfalfa silage, duodenal amino acids, sheep, rumen digestion

scholarly journals The case for regulating indispensable amino acid metabolism: the branched-chain α-keto acid dehydrogenase kinase-knockout mouse

2006 ◽  
Vol 400 (1) ◽  
Author(s):  
Susan M. Hutson
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Essential Amino Acids ◽  
The Body ◽  
Keto Acid ◽  
Acid Dehydrogenase ◽  
Indispensable Amino Acid ◽  
Branched Chain

BCAAs (branched-chain amino acids) are indispensable (essential) amino acids that are required for body protein synthesis. Indispensable amino acids cannot be synthesized by the body and must be acquired from the diet. The BCAA leucine provides hormone-like signals to tissues such as skeletal muscle, indicating overall nutrient sufficiency. BCAA metabolism provides an important transport system to move nitrogen throughout the body for the synthesis of dispensable (non-essential) amino acids, including the neurotransmitter glutamate in the central nervous system. BCAA metabolism is tightly regulated to maintain levels high enough to support these important functions, but at the same time excesses are prevented via stimulation of irreversible disposal pathways. It is well known from inborn errors of BCAA metabolism that dysregulation of the BCAA catabolic pathways that leads to excess BCAAs and their α-keto acid metabolites results in neural dysfunction. In this issue of Biochemical Journal, Joshi and colleagues have disrupted the murine BDK (branched-chain α-keto acid dehydrogenase kinase) gene. This enzyme serves as the brake on BCAA catabolism. The impaired growth and neurological abnormalities observed in this animal show conclusively the importance of tight regulation of indispensable amino acid metabolism.

Protein degradation and synthesis measured with multiple amino acid tracers in vivo

1996 ◽  
Vol 271 (4) ◽  
pp. E733-E741 ◽  
Author(s):  
P. Tessari ◽  
R. Barazzoni ◽  
M. Zanetti ◽  
M. Vettore ◽  
S. Normand ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Protein S ◽  
Essential Amino Acids ◽  
Body Protein ◽  
Amino Acid Availability ◽  
Before And After ◽  
Branched Chain ◽  
Multiple Amino Acid

Whether tracers of different essential amino acids yield the same estimates of body protein turnover is still uncertain. Therefore, we have simultaneously determined leucine (Leu; using [14C]Leu), phenylalanine (Phe; using [13C]Phe), and tyrosine (Tyr; using [2H2]Tyr) rates of appearance (Ra) from proteolysis (PD), as well as Leu and Phe disposal, into protein synthesis (PS) both before and after an anabolic stimulus in healthy volunteers. Protein anabolism was stimulated by insulin plus a branched-chain amino acid-enriched aromatic amino acid-deficient amino acid solution, which increased Leu (from 145 +/- 9 to 266 +/- 10 mumol/l) but decreased Phe (from 57 +/- 2 to 46 +/- 3) and Tyr (from 58.7 +/- 5.5 to 21.0 +/- 2.2) concentrations. Postabsorptive endogenous Leu Ra (2.04 +/- 0.12 mumol.kg-1.min-1), Phe Ra (0.66 +/- 0.03), and Tyr Ra (0.45 +/- 0.06), as well as rates of PS determined with the leucine (1.65 +/- 0.10 mumol.kg-1.min-1) and the phenylalanine tracer (0.57 +/- 0.03), agreed well with the known abundance of these amino acids in body protein(s). After insulin and amino acids, PD was suppressed (P < 0.001) using all tracers. However, although percent suppression of endogenous Leu Ra (-->1.49 +/- 0.10 mumol.kg-1.min-1, 26 +/- 5%) and Phe Ra (-->0.53 +/- 0.02 mumol.kg-1.min-1, -20 +/- 2%) were comparable, endogenous Tyr Ra was suppressed to a larger extent (-->0.23 +/- 0.02 mumol.kg-1.min-1, -46 +/- 3% P = 0.038). PS was stimulated using the Leu (+24 +/- 7%, P < 0.02) but not the Phe (+6 +/- 4%, not significant) data. We conclude that isotopes of different essential amino acid: provide comparable estimates of PD and PS in the postabsorptive state. However, their responses to an anabolic stimulus may differ, possibly depending on exogenous amino acid availability and/or the resulting plasma levels.

scholarly journals Idendification of sulphur-rich proteins which resist rumen degradation and are hydrolysed rapidly by intestinal proteases

1994 ◽  
Vol 72 (6) ◽  
pp. 855-863 ◽  
Author(s):  
Kerrie R. Hancock ◽  
Paul M. Ealing ◽  
Derek W.R. White
Keyword(s):  
Amino Acids ◽  
Rumen Fluid ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Essential Amino Acids ◽  
Rumen Degradation ◽  
Foreign Proteins ◽  
Sheep Rumen ◽  
Pasture Plants

Several proteins with high proportions of S-containing essential amino acids were incubated in sheep rumen fluid in vitro and their rate of digestion was examined by sodium dodecyl sulphate-polyacrylamide-gel electrophoresis. The S-rich proteins rice prolamin (10 kDa), maize zein (10 kDa) and the 3·2 kDa pumpkin (Cucurbita maxima L.) trypsin inhibitor-1 (CMTI-1) were highly resistant to rumen fluid degradation, relative to control proteins of known degradation rate (casein, bovine serum albumin (BSA) and pea (Pisum sativum) albumin-1 (PA1)). Comparison of PA1 and a recombinant N-terminal epitope-tagged PA1 indicated that addition of the epitope caused a slight increase in resistance to rumen degradation. The proteins were also incubated with a mixture of trypsin (EC 3·4·21·4) and chymotrypsin (EC 3·4·21.1). PA1, BSA and casein were hydrolysed less rapidly than rice prolamin, maize zein and CMTI-1. Digestion by these intestinal proteases appeared to be complete. Thus, the prolamin, zein and CMTI-1 proteins are suitable candidates for expression as foreign proteins in pasture plants to increase throughput and uptake of essential amino acids in sheep.

scholarly journals The effect of forage and forage–concentrate diets on rumen fermentation and metabolism of nutrients by the mesenteric- and portal-drained viscera in growing steers

1992 ◽  
Vol 67 (3) ◽  
pp. 355-370 ◽  
Author(s):  
C. J. Seal ◽  
D. S. Parker ◽  
P. J. Avery
Keyword(s):  
Amino Acids ◽  
Rumen Fluid ◽  
Essential Amino Acids ◽  
Nutrient Utilization ◽  
Whole Body ◽  
Glucose Turnover ◽  
Mucosal Tissue ◽  
Branched Chain Amino Acid ◽  
Portal Veins ◽  
Branched Chain

Growing Friesian steers chronically catheterized in the anterior mesenteric and portal veins were used to study the influence of feeding with either a forage or forage–concentrate diet on nutrient utilization by mucosal tissue. When animals were consuming the forage–concentrate diet the molar proportion of propionate in rumen fluid was significantly increased, although production rate as measured by isotope dilution was not altered. Net rates of absorption of VFA into portal blood when compared with rumen production rates underlined the extent to which metabolism within mucosal tissue modifies the propionate supply to the liver. Net glucose utilization by splanchnic tissue was shown to be significantly lower on the forage–concentrate diet. There were no effects of diet on whole-body glucose turnover or on the proportion of glucose derived from propionate. Animals fed on the forage–concentrate diet had significantly lower concentrations of circulating essential amino acids, due mainly to a reduction in branched-chain amino acid levels. There was net absorption of all amino acids by animals on both diets except for glutamate, glutamine and taurine in forage-fed animals.

scholarly journals Clustering of ingredients with amino acid composition similar to the nutritional requirement of Nile tilapia

2010 ◽  
Vol 67 (5) ◽  
pp. 517-523 ◽  
Author(s):  
Álvaro José de Almeida Bicudo ◽  
Luis Fernando Batista Pinto ◽  
José Eurico Possebon Cyrino
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Principal Components ◽  
Nile Tilapia ◽  
Principal Component ◽  
Essential Amino Acids ◽  
Amino Acid Profile ◽  
Nutritional Requirement ◽  
Dietary Amino Acids ◽  
The Relationship

The search for balanced diets, which may elicit improved growth of fish, requires appropriate selection of available protein sources. This study aims at clustering feedstuffs according to amino acid profile, determining which ones show essential amino acids (EAA) profiles closer to the ideal dietary amino acids requirements of Nile tilapia (Oreochromis niloticus), and studying the relationship among amino acids feedstuffs groups. Tabled data on EAA more cystine and tyrosine, in relation to lysine contents, of 40 feedstuffs ordinarily used to formulate fish diets were studied. Feedstuffs were grouped according to amino acids profile by cluster analysis of Euclidean distances. The principal components analysis was used to determine the relationship among amino acids in each feedstuff group. Three groups of ingredients were parted and two ingredients, low tannin sorghum and corn gluten meal 60%, did not go with any group. Dietary amino acids requirements of Nile tilapia were similar to the amino acid profile of 22 feedstuffs. The principal component analysis explained with three principal components more than 75% of total variance of amino acids in three feedstuff groups. Therefore, until additional, detailed information on amino acids availability of different ingredients is consolidated, total amino acids profiles will continue to be important information to select and use conventional or surrogate ingredients for formulating and processing feeds for tilapia.

scholarly journals Mice Lacking the Intestinal and Renal Neutral Amino Acid Transporter SLC6A19 Demonstrate the Relationship between Dietary Protein Intake and Amino Acid Malabsorption

Nutrients ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 2024 ◽  
Author(s):  
Kiran Javed ◽  
Stefan Bröer
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Dietary Protein ◽  
Protein Intake ◽  
Essential Amino Acids ◽  
Protein Restriction ◽  
Intestinal Lumen ◽  
Dietary Protein Intake ◽  
Neutral Amino Acids ◽  
The Relationship

Dietary protein restriction has beneficial impacts on metabolic health. B0AT1 (SLC6A19) is the major transporter of neutral amino acids at the intestinal epithelia and absorbs the bulk of the diet-derived neutral amino acids from the intestinal lumen. It also reabsorbs neutral amino acids in the renal proximal tubules. Mice lacking B0AT1 show cellular outcomes of protein restriction, such as high FGF21 levels and low mTORC1 activity. Moreover, they have improved glucose homeostasis and resist diet-induced obesity. In this study, we investigated the relationship between protein restriction and dietary protein intake in C57Bl6/J wild-type (wt) and SLC6A19-knockout (SLC6A19ko) mice. When SLC6A19ko mice were fed diets containing 5%, 25%, or 52% of their total calories derived from protein, no differences in food intake or weight gain were observed. All essential amino acids significantly positively correlated with increasing dietary casein content in the wt mice. The SLC6A19ko mice showed reduced postprandial levels of essential amino acids in plasma, particularly following high-protein diets. Upon fasting, essential amino acids were the same in the wt and SLC6A19ko mice due to reduced amino acid catabolism. Bacterial metabolites originating from amino acid fermentation correlated with the dietary protein content, but showed a complex profile in the blood of the SLC6A19ko mice. This study highlights the potential of SLC6A19 as a knock-out or inhibition target to induce protein restriction for the treatment of metabolic disorders.

Regional amino acid transport into brain during diabetes: effect of plasma amino acids

1987 ◽  
Vol 253 (5) ◽  
pp. E575-E583 ◽  
Author(s):  
A. M. Mans ◽  
M. R. DeJoseph ◽  
D. W. Davis ◽  
R. A. Hawkins
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Transport ◽  
Basic Amino Acid ◽  
Essential Amino Acids ◽  
Diabetic Rats ◽  
Transport Systems ◽  
Plasma Amino Acids ◽  
Acid Transport ◽  
Branched Chain

Transport of phenylalanine and lysine into the brain was measured in 4-wk streptozotocin-diabetic rats to assess the effect on the neutral and basic amino acid transport systems at the blood-brain barrier. Amino acid concentrations in plasma and brain were also measured. Regional permeability-times-surface area (PS) products and influx were determined using a continuous infusion method and quantitative autoradiography. The PS of phenylalanine was decreased by an average of 40% throughout the entire brain. Influx was depressed by 35%. The PS of lysine was increased by an average of 44%, but the influx was decreased by 27%. Several plasma neutral amino acids (branched chain) were increased, whereas all basic amino acids were decreased. Brain tryptophan, phenylalanine, tyrosine, methionine, and lysine contents were markedly decreased. The transport changes were almost entirely accounted for by the alterations in the concentrations of the plasma amino acids that compete for the neutral and basic amino acid carriers. The reduced influx could be responsible for the low brain content of some essential amino acids, with possibly deleterious consequences for brain function.

scholarly journals Multi-omics data reveal genes that are relevant for muscular amino acids in the common carp

2020 ◽  
Author(s):  
Youxiu Zhu ◽  
Hanyuan Zhang ◽  
Peng Xu ◽  
Zixia Zhao ◽  
Jianxin Feng ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Common Carp ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Essential Amino Acids ◽  
Muscle Tissues ◽  
The Common ◽  
Branched Chain ◽  
Amino Acid Contents

Abstract Background Fish muscular amino acids are a series of essential nutrients that embrace essential amino acids, branched-chain amino acids and flavorous amino acids. Previous studies have found that amino acids have important physiological effects on fish growth and development, as they are involved in maintaining nitrogen balance and in the formation of enzymes and hormones. Amino acids, such as aspartic acid, glutamic acid, glycine and alanine, that can have a significant effect on fish umami taste are called flavorous amino acids. Nevertheless, the studies on the genetic mechanisms of amino acid metabolism in the common carp (Cyprinus carpio) are still limited. Results The purpose of this study was to examine the divergent patterns at the genomic, transcriptomic and epigenomic levels in fish with different amino acid contents. Genome-wide association analysis using 195 individuals of common carp was conducted, and 62 genes were identified to be associated with glycine, proline, and tyrosine content. RNA-Seq of samples with extreme contents of essential amino acids, branched-chain amino acids and flavorous amino acids was applied using brain, liver and muscle tissues, resulting in 1,643 differentially expressed genes. Whole-genome bisulfite sequencing identified 3,108 genes with differentially methylated promoters. Through the enrichment analysis of transcriptome and DNA methylation results, we screened out a series of enriched pathways associated with amino acid metabolism, including various categories of pathways spanning growth regulation, lipid metabolism, the citrate cycle and other signaling pathways. Integrated studies demonstrated prominent correlations between DGE and DMP for amino acid contents trait in brain and muscle tissues. Conclusion In summary, the multi-omics data revealed candidate genes and pathways correlated with amino acid metabolism. These results will promote the process of the genomic selection and breeding strategy in muscular amino acid contents of fish.

scholarly journals Multi-omics data reveal genes that are relevant for muscular amino acids in the common carp

2021 ◽  
Author(s):  
Youxiu Zhu ◽  
Hanyuan Zhang ◽  
Peng Xu ◽  
Zixia Zhao ◽  
Jianxin Feng ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Common Carp ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Essential Amino Acids ◽  
Muscle Tissues ◽  
The Common ◽  
Branched Chain ◽  
Amino Acid Contents

Abstract Background: Fish muscular amino acids are a series of essential nutrients that embrace essential amino acids, branched-chain amino acids and flavorous amino acids. Previous studies have found that amino acids have important physiological effects on fish growth and development, as they are involved in maintaining nitrogen balance and in the formation of enzymes and hormones. Amino acids, such as aspartic acid, glutamic acid, glycine and alanine, that can have a significant effect on fish umami taste are called flavorous amino acids. Nevertheless, the studies on the genetic mechanisms of amino acid metabolism in the common carp (Cyprinus carpio) are still limited.Results: The purpose of this study was to examine the divergent patterns at the genomic, transcriptomic and epigenomic levels in fish with different amino acid contents. Genome-wide association analysis using 195 individuals of common carp was conducted, and 62 genes were identified to be associated with glycine, proline, and tyrosine content. RNA-Seq of samples with extreme contents of essential amino acids, branched-chain amino acids and flavorous amino acids was applied using brain, liver and muscle tissues, resulting in 1,643 differentially expressed genes. Whole-genome bisulfite sequencing identified 3,108 genes with differentially methylated promoters. Through the enrichment analysis of transcriptome and DNA methylation results, we screened out a series of enriched pathways associated with amino acid metabolism, including various categories of pathways spanning growth regulation, lipid metabolism, the citrate cycle and other signaling pathways. Integrated studies demonstrated prominent correlations between DGE and DMP for amino acid contents trait in brain and muscle tissues.Conclusions: In summary, the multi-omics data revealed candidate genes and pathways correlated with amino acid metabolism. These results will promote the process of the genomic selection and breeding strategy in muscular amino acid contents of fish.

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