Influence of white- and red-sorghum varieties and hydrothermal component of steam-pelleting on digestibility coefficients of amino acids and kinetics of amino acids, nitrogen and starch digestion in diets for broiler chickens

2013 ◽  
Vol 186 (1-2) ◽  
pp. 53-63 ◽  
Author(s):  
S.Y. Liu ◽  
P.H. Selle ◽  
A.J. Cowieson
Keyword(s):  
Amino Acids ◽  
Broiler Chickens ◽  
Starch Digestion ◽  
Kinetics Of

The kinetics of starch and nitrogen digestion regulate growth performance and nutrient utilisation of broilers fed coarsely ground, sorghum-based diets

2013 ◽  
Vol 53 (10) ◽  
pp. 1033 ◽  
Author(s):  
S. Y. Liu ◽  
P. H. Selle ◽  
A. J. Cowieson
Keyword(s):  
Feed Efficiency ◽  
Broiler Chickens ◽  
Nitrogen Retention ◽  
Proximal Jejunum ◽  
Protein Digestion ◽  
Starch Digestion ◽  
Digestion Rate ◽  
Nutrient Utilisation ◽  
Digestion Kinetics ◽  
Kinetics Of

A study was conducted to examine the effect of starch and nitrogen digestion kinetics on broiler performance using sorghum-based diets as a model. Three sorghum varieties with red, white and yellow pericarps and three feed forms, mash, intact pellets and reground pellets, constituted a 3 × 3 factorial array of dietary treatments. Starch and nitrogen digestion kinetics were determined using an exponential mathematical model to relate digestion coefficients in the proximal jejunum, proximal ileum and distal ileum with mean retention times in each segment. There were interactions between sorghum variety and feed form for starch and nitrogen digestion kinetics. Steam-pelleting at a conditioning temperature of 90°C (unprocessed mash versus reground pellets) substantially influenced starch digestion rate in red and yellow sorghum-based diets, but not in white sorghum-based diets. Alternatively, with nitrogen digestion rate, there were no significant differences in yellow sorghum-based diets between feed forms but there were in red and white sorghum-based diets. The digestion rate of starch was more rapid than nitrogen, especially in the proximal jejunum. Starch digestion rates were significantly correlated with nitrogen retention but this was not the case with nitrogen digestion rates. The rate of glucose absorption from predicted glycaemic indices was highly correlated with enhanced feed efficiency. Thus this study demonstrates that even under ad libitum feeding regimes, kinetics of starch and protein digestion regulated feed efficiency and nitrogen retention in broiler chickens. The dynamics of starch and protein digestion were more accurate indicators of feed efficiency and nitrogen retention than apparent ileal starch and nitrogen digestibility.

The Kinetics of Inhibition of the Action of Thrombin by the Fibrinopeptides Formed during the Clotting of Fibrinogen

1966 ◽  
Vol 16 (01/02) ◽  
pp. 277-295 ◽  
Author(s):  
A Silver ◽  
M Murray
Keyword(s):  
Amino Acids ◽  
Competitive Inhibition ◽  
Amorphous Material ◽  
Peptide Bond ◽  
Initial Reaction ◽  
Reaction Products ◽  
Coagulation Mechanism ◽  
Kinetics Of ◽  
Kinetics Of Inhibition ◽  
Burk Plot

SummaryVarious investigators have separated the coagulation products formed when fibrinogen is clotted with thrombin and identified fibrinopeptides A and B. Two other peaks are observed in the chromatogram of the products of coagulation, but these have mostly been dismissed by other workers. They have been identified by us as amino acids, smaller peptides and amorphous material (37). We have re-chromatographed these peaks and identified several amino acids. In a closed system of fibrinogen and thrombin, the only reaction products should be fibrin and peptide A and peptide B. This reasoning has come about because thrombin has been reported to be specific for the glycyl-arginyl peptide bond. It is suggested that thrombin also breaks other peptide linkages and the Peptide A and Peptide B are attacked by thrombin to yield proteolytic products. Thrombin is therefore probably not specific for the glycyl-arginyl bond but will react on other linkages as well.If the aforementioned is correct then the fibrinopeptides A and B would cause an inhibition with the coagulation mechanism itself. We have shown that an inhibition does occur. We suggest that there is an autoinhibition to the clotting mechanism that might be a control mechanism in the human body.The experiment was designed for coagulation to occur under controlled conditions of temperature and time. Purified reactants were used. We assembled an apparatus to record visually the speed of the initial reaction, the rate of the reaction, and the density of the final clot formed after a specific time.The figures we derived made available to us data whereby we could calculate and plot the information to show the mechanism and suggest that such an inhibition does exist and also further suggest that it might be competitive.In order to prove true competitive inhibition it is necessary to fulfill the criteria of the Lineweaver-Burk plot. This has been done. We have also satisfied other criteria of Dixon (29) and Bergman (31) that suggest true competitive inhibition.

scholarly journals Progress towards reduced-crude protein diets for broiler chickens and sustainable chicken-meat production

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sonia Yun Liu ◽  
Shemil P. Macelline ◽  
Peter V. Chrystal ◽  
Peter H. Selle
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Broiler Chickens ◽  
Crude Protein ◽  
Plasma Concentrations ◽  
Essential Amino Acids ◽  
Chicken Meat ◽  
Meat Production ◽  
Accurate Identification ◽  
Reduced Crude Protein

AbstractThe prime purpose of this review is to explore the pathways whereby progress towards reduced-crude protein (CP) diets and sustainable chicken-meat production may be best achieved. Reduced-CP broiler diets have the potential to attenuate environmental pollution from nitrogen and ammonia emissions; moreover, they have the capacity to diminish the global chicken-meat industry’s dependence on soybean meal to tangible extents. The variable impacts of reduced-CP broiler diets on apparent amino acid digestibility coefficients are addressed. The more accurate identification of amino acid requirements for broiler chickens offered reduced-CP diets is essential as this would diminish amino acid imbalances and the deamination of surplus amino acids. Deamination of amino acids increases the synthesis and excretion of uric acid for which there is a requirement for glycine, this emphasises the value of so-called “non-essential” amino acids. Starch digestive dynamics and their possible impact of glucose on pancreatic secretions of insulin are discussed, although the functions of insulin in avian species require clarification. Maize is probably a superior feed grain to wheat as the basis of reduced-CP diets; if so, the identification of the underlying reasons for this difference should be instructive. Moderating increases in starch concentrations and condensing dietary starch:protein ratios in reduced-CP diets may prove to be advantageous as expanding ratios appear to be aligned to inferior broiler performance. Threonine is specifically examined because elevated free threonine plasma concentrations in birds offered reduced-CP diets may be indicative of compromised performance. If progress in these directions can be realised, then the prospects of reduced-CP diets contributing to sustainable chicken-meat production are promising.

Kinetics and mechanism of oxidation of DL-α-alanine by permanganate ion in acid perchlorate media

1991 ◽  
Vol 69 (12) ◽  
pp. 2018-2023 ◽  
Author(s):  
Refat M. Hassan
Keyword(s):  
Amino Acids ◽  
Ionic Strength ◽  
Acid Solution ◽  
Second Order ◽  
Perchloric Acid Solution ◽  
Oxidation Reduction ◽  
Initial Stage ◽  
Aqueous Perchloric Acid ◽  
Mechanism Of Oxidation ◽  
Kinetics Of

The kinetics of permanganate oxidation of DL-α-alanine in aqueous perchloric acid solution at a constant ionic strength of 2.0 mol dm−3 has been investigated spectrophotometrically. The reaction was found to show second-order kinetics overall with respect to each of the reactants in the slow initial stage; the second-order kinetics are not, however, maintained throughout the relatively fast final stage of reaction. The added salts lead to the prediction that Mn(III) and (or) Mn(IV) play a very important role in the reaction kinetics. A tentative mechanism consistent with the kinetics is discussed. Key words: kinetics, oxidation, reduction, amino acids, permanganate.

SOME ASPECTS OF THE STRUCTURE OF HEMOGLOBIN

1964 ◽  
Vol 42 (6) ◽  
pp. 755-762 ◽  
Author(s):  
David B. Smith
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Partial Amino Acid Sequence ◽  
Heme Pocket ◽  
Terminal Amino ◽  
Polypeptide Chains ◽  
Kinetics Of ◽  
Β Chain

An outline of present ideas concerning the arrangement, folding, and chemistry of the polypeptide chains of hemoglobin is given with some references to present know ledge of myoglobin.New material includes a partial amino acid sequence of the β-chain of horse hemoglobin, details concerning the amino acids lining the heme pocket of horse hemoglobin, and the effects of carboxypeptidases A and B on horse oxy- and horse deoxy-hemoglobin. The kinetics of the latter reactions are not simple. The C-terminal amino acids are released more rapidly from the oxygenated form.

scholarly journals Identification in skeletal muscle of a distinct extracellular pool of amino acids, and its role in protein synthesis

1971 ◽  
Vol 121 (5) ◽  
pp. 817-827 ◽  
Author(s):  
R. C. Hider ◽  
E. B. Fern ◽  
D. R. London
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Incubation Medium ◽  
Extensor Digitorum Longus ◽  
Extensor Digitorum ◽  
Longus Muscle ◽  
Kinetics Of

1. The kinetics of radioactive labelling of extra- and intra-cellular amino acid pools and protein of the extensor digitorum longus muscle were studied after incubations with radioactive amino acids in vitro. 2. The results indicated that an extracellular pool could be defined, the contents of which were different from those of the incubation medium. 3. It was concluded that amino acids from the extracellular pool, as defined in this study, were incorporated directly into protein.

scholarly journals Metabolic and endocrine changes induced by chronic heatexposure in broiler chickens : biological and endocrinological variables

1996 ◽  
Vol 75 (2) ◽  
pp. 205-216 ◽  
Author(s):  
P. A. Geraert ◽  
J. C. F. Padilha ◽  
S. Guillaumin
Keyword(s):  
Amino Acids ◽  
Ambient Temperature ◽  
Broiler Chickens ◽  
De Novo ◽  
Heat Exposure ◽  
Plasma Corticosterone ◽  
Plasma Metabolites ◽  
Exogenous Insulin ◽  
Plasma Insulin Concentration ◽  
Esterified Fatty Acids

Abstract:The present study was designed to investigate the effect of chronic heat exposure (32° constant) on plasma metabolites and hormone concentrations in broiler chickens. At 2 and 4 weeks of age, fifty-four male Shaver broiler chickens were allocated to one of three treatments: 22°ad lib. feeding (22AL), 32°ad lib. feeding (32AL) and 22°,pair-feeding with the 32AL group (22PF). Ambient temperature was kept constant at either 22 or 32° for 2 weeks. Plasma glucose, triacylglycerols, phospholipids, non-esterified fatty acids (NEFA), individual amino acids, uric acid, insulin, triiodothyronine (T3), thyroxine, corticosterone were determined. Sensitivity to exogenous insulin was also measured at 7 weeks of age. At 4 and 6 weeks of age, i.e. after 2 weeks at high ambient temperature, fasted 32AL chickens displayed similar concentrations of glucose and triacylglycerols to those of 22AL birds. When fed, 32AL chickens exhibited higher plasma levels of glucose and decreased concentrations of NEFAand amino acids. Feed restriction resulted in intermediate values. Concentrations of all plasmafree amino acids were decreased under heat exposure except for aspartic acid, glutamic acid andphenylalanine. At 6 weeks of age, plasma T3 was reduced irrespective of the nutritional state, while plasma corticosterone concentrations were increased in 32AL birds compared with 22AL birds. Heat exposure did not change plasma insulin concentration in either fasted or fed chickens. The 32AL chickens displayed significantly reduced sensitivity to exogenous insulin when fasted,but an enhanced response to insulin when fed, compared with both 22° groups. Such endocrinological changes could stimulate lipid accumulation through increasedde novolipogenesis, reduced lipolysis and enhanced amino acid catabolism under chronic heat exposure.

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