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1.
Calves are born with a mostly inadequate essential amino acid (EAA) status. Studies were designed to test the hypothesis that delaying the intake of the first colostrum for 24 h, besides its early effects, also has late effects on plasma free amino acid levels and on the protein status. There were marked and rapid elevations (within 2 h) of plasma levels of various amino acids, and especially of EAA, after the intake of the first colostrum, whereas changes after the intake of mature milk on day 28 of life were mostly absent or concentrations even decreased. The EAA and non-essential amino acid (NEAA) status was rapidly normalized after intake of the first colostrum, but normal plasma levels of some amino acids were also reached during the first 24 h of life even when the first meal was withheld. Delaying colostrum intake had only transient effects on EAA and NEAA (except hydroxyproline), in contrast to its effects on plasma immunoglobulin G and total protein levels.  相似文献   

2.
Plasma bile acids, plasma amino acids, and the total hepatic pools of aspartate aminotransferase, gamma glutamyltransferase, glutamate dehydrogenase, and sorbitol dehydrogenase were compared in control sheep (Group 1), sheep with subclinical pyrrolizidine alkaloid toxicosis (Group 2), and in sheep with acute hepatocellular necrosis associated with the hemolytic phase of chronic copper poisoning (Group 3). Subclinical pyrrolizidine alkaloid toxicosis was not associated with any changes in bile acid or amino acid status but was associated with a significant decline in the hepatic pools of sorbitol dehydrogenase and aspartate aminotransferase. This observation could not be explained in terms of enzyme leakage from damaged hepatocytes and suggested that pyrrolizidine alkaloids might specifically inhibit hepatocellular enzyme synthesis. Group 3 sheep also had reduced hepatic enzyme pools which were at least partly referable to enzyme leakage from damaged hepatocytes. In these sheep, increases in plasma bile acids were a more sensitive index of hepatic function than were either increased aromatic amino acid concentration or the ratio between branched chain and aromatic amino acids.  相似文献   

3.
To determine whether equine dysautonomia (ED) is associated with alterations in plasma amino acid metabolism, plasma amino acid profiles were determined for horses with acute (n = 10), subacute (n = 6) and chronic (n = 7) ED and for healthy cograzing horses (n = 6) and control horses (n = 10). Horses with acute ED had perturbations in plasma amino acid profiles resembling those of severe protein malnutrition. In addition, horses with ED and cograzing healthy horses had depletion of the plasma sulphur amino acids cyst(e)ine and methionine. As similar plasma amino acid perturbations occur in subacute/chronic cyanide toxicity, the role of cyanogenic glycosides in the aetiology of ED warrants further study. Unfortunately, amino acid analysis cannot be used as a definitive premortem diagnostic test for ED, since there was overlap in the individual amino acid levels of control, cograzing and ED horses.  相似文献   

4.
 通过检测泌乳中期山羊血浆及乳中游离氨基酸含量的变化,探讨不同精粗比饲料对机体中氨基酸（ａｍｉｎｏａｃｉｄｓ,ＡＡ）的代谢流向及乳蛋白的影响。选用泌乳中期山羊７只,随机分为２组,分别饲喂精粗比４∶６（低精料组）和６∶４（高精料组）日粮,颈静脉血管瘘采血,手工挤奶取奶样。Ｂｒａｄｆｏｒｄ法测定乳中总蛋白质浓度,ＲＰ－ＨＰＬＣ检测山羊血浆和乳中游离氨基酸的含量。结果表明,２组山羊血浆中均分离出１４种游离氨基酸,乳中分离出８种游离氨基酸,不同精粗比饲料对血液或乳中游离氨基酸谱无明显影响。不同精粗比日粮情况下,除丙氨酸外,血液中游离氨基酸的含量均高于乳中同种氨基酸的含量;且血液中生酮氨基酸（Ｌｅｕ,Ｌｙｓ）、兼性氨基酸（Ｐｈｅ,Ｉｌｅ）和支链氨基酸（Ｌｅｕ,Ｉｌｅ和Ｖａｌ）含量显著或极显著高于乳中。高精料组除Ｇｌｙ和Ａｌａ外,其余氨基酸含量均低于低精料组;乳中总蛋白浓度略高于低精料组,但无统计学差异。表明血液中游离氨基酸为乳蛋白的合成提供了原料和能量保证。饲喂高精料日粮,血液中游离氨基酸含量较低,不利于乳蛋白含量和产量的提高。  相似文献   

5.
Plasma and blood-cell free amino acid concentrations and venoarterial differences across the hindlimbs via abdominal aorta and caudal vena cava cannulae were determined on Holstein steer calves (130 kg) fed purified diets containing soy protein or urea as the sole source of dietary N. Calves were fed 24 hourly feedings per day to promote "steady-state" metabolism. Trials lasted 30 d and consisted of four calves per treatment. Urea feeding resulted in reduced venous concentrations of plasma amino acids, namely, a 30% decrease in essential amino acids (P less than .05) and a 16% decrease in nonessential amino acids (P less than .10). Nonessential amino acid concentrations of blood cells were affected little in urea-fed calves; however, blood-cell essential amino acid concentrations were depressed due to significant decreases in threonine, valine, methionine, isoleucine and phenylalanine. A net negative concentration difference across the hindlimbs for plasma free amino acids was noted for soy-fed calves. Urea feeding resulted in a small positive amino acid concentration difference. The branched-chain amino acids (BCAA) changed (P less than .01) from a large negative concentration difference in soy-fed calves to essentially a zero difference in calves fed urea. Blood-cell total amino acid change across hindlimbs showed no treatment differences, although BCAA changed from large outputs from the blood cells in soy-fed calves to essentially zero change in urea-fed calves.  相似文献   

6.
OBJECTIVE: To characterize the effect of maintenance hemodialysis on plasma amino acid concentrations and to quantitate free amino acid losses into the dialysate during hemodialysis in healthy dogs. ANIMALS: 8 healthy adult dogs. PROCEDURE: Five dogs received hemodialysis treatments 3 times per week for 4 weeks. Plasma amino acid concentrations were evaluated once per week for 4 weeks in each of the 5 dogs prior to hemodialysis (time 0), 90 minutes during hemodialysis, and immediately after hemodialysis (180 minutes). Total free amino acid concentrations and plasma amino acid concentrations (time 0, 90 minutes, and 180 minutes) in the dialysate were evaluated in 3 dogs that received 1 hemodialysis treatment. RESULTS: Significant time versus week interactions with any plasma amino acid were not detected; however, significant decreases in all plasma amino acid concentrations measured were detected at the midpoint of dialysis (46 +/- 2%) and at the end of each dialysis session (38 +/- 2%). Mean (+/- SEM) total free amino acid loss into the dialysate was 2.7 +/- 0.2 g or 0.12 g/kg of body weight. CONCLUSIONS AND CLINICAL RELEVANCE: Hemodialysis is associated with significant alterations in plasma amino acid concentrations and loss of free amino acids into the dialysate. Loss of amino acids into the dialysate, coupled with protein calorie malnutrition in uremic patients, may contribute to depletion of amino acid stores.  相似文献   

7.
Trials were conducted with four adult sheep of the Merino breed, live weight 45 to 50 kg, fed two diets with different nitrogen levels (7.6 g nitrogen per day as protein or 24 g nitrogen per day with an addition of 17.4 g urea nitrogen to 7.6 g nitrogen as protein). The following findings were obtained: the concentration of free amino acids in blood plasma in the 9th, 12th, 15th, 18th and 22nd weeks from the beginning of feeding with both diets was lower, in most of the analyzed amino acids, three hours after feeding than before feeding. The results show that at an increased intake of urea nitrogen the concentration increases of the free amino acids lysine, serine, glutamic acid, glycine, valine and isoleucine before feeding. Three hours after feeding these differences are less pronounced. An increase is only recorded in the concentration of arginine, glutamic acid and glycine, whereas the concentration of alanine decreases.  相似文献   

8.
Six horses were conditioned on a treadmill at a constant speed of 5.6 km/hr on a 12.5% grade for gradually increasing periods of time over 14 days in order to determine the effect of repeated submaximal exercise on the concentrations of plasma free amino acids, protein metabolism, and plasma volume. Following 14-days of training, plasma volume increased (29%, P<0.05), as did total circulating content of plasma protein, albumin and urea. Urinary urea nitrogen excretion decreased (P<0.05) with exercise training. After the first week of training, the concentration of glycine had decreased (P<0.05) and the concentrations glutamic acid, arginine and alanine were increased (P<0.05) when compared to their corresponding pre-training (control week) levels. Compared to pretraining levels, there were decreases (P<0.05) in aspartic acid, histidine, arginine, valine, phenylalanine, isoleucine, and lysine, following the second week of training. Following a week of recovery, all resting concentrations of plasma free amino acids; when compared to their pretraining control; had decreased, with the exception of three nonessential amino acids (glutamic acid,serine, and glycine). Based upon the results of the present study, it would appear that exercise training produced a significant change in the amino acid and protein metabolism of the horse.  相似文献   

9.
A large-scale trial was carried out under commercial conditions to investigate to which extent the feeding of rations with varying lysine content to young hens would influence the crude nutrient content of the body fractions and might change the pattern of amino acid composition and the activity of GOT in the blood. Four rations were fed each containing 14.2% crude protein, 626-633 EFh units/kg and 0.59%, 0.61%, 0.54% and 0.46% lysine. The crude protein and crude fat content of the total body and of body fractions were in no case found to be related to the feeding regime. The proportion of crude ash in the "remainder of non-utilizable parts", in "bones", "intestinal and abdominal fat", "ovaries" and "small intestine" decreased with the decreasing lysine content of the rations. The concentrations of free lysine, histidine, arginine, and phenylalanine in the deproteinized blood plasma of the young hens were significantly (a = 0.01) lower in the birds of the lysine deficient group than in the hens of the other groups. Positive regressions were calculated for the lysine content or the content of aspartic acid in the ration and the pattern of free amino acids in blood plasma. Positive and negative linear relationships were found to exist between the concentrations of free lysine, and those of histidine, arginine or threonine, and serine. A close correlation existed between the total amount of essential amino acids in blood plasma and the lysine concentrations of the plasma. Increasing lysine supplementation produced a decline in the N content of the whole blood and blood corpuscles but a rise in the N content of blood plasma. The activity of GOT in the blood of young hens was not found to be useful as an indicator of the quality of dietary proteins.  相似文献   

10.
A three‐day assay was developed to evaluate the effect of autoclaving on protein quality of vetch as an alternative to classical growth methods. Male chickens (n = 10/diet) were given approximately isonitrogenous diets based on raw or autoclaved vetch for 3 days. Samples of plasma, muscle and liver were obtained for free amino acid analysis. Heating vetch depressed growth (11.9 vs. 23.2 g/d; p < 0.05). Plasma methionine and histidine increased (0.05 < p < 0.06), while gluconeogenic amino acids tended to decrease (p < 0.10) after heating. Muscle free amino acids did not change except for a trend to increased methionine (p = 0.06) in birds fed autoclaved vetch. In liver, most essential amino acids, glycine, proline and tyrosine increased markedly with heated vetch diet. Correlations between plasma and muscle free amino acids were poor compared with those between plasma and liver free amino acids. Liver free amino acid pool was more sensitive than muscle or plasma pool to amino acid inflow modifications after vetch heating.  相似文献   

11.
为了探讨饲喂不同精粗比日粮对肝脏氨基酸分配与重分配的影响及可能的机制,本研究选择6只安装了肝脏多血管瘘的健康泌乳奶山羊,分别饲喂精粗比为40∶60(对照组)和60∶40(高精料组)的饲料,2×2拉丁方设计,饲喂期16周。期间取乳样,测定乳蛋白含量,并通过肝门静脉、肝静脉和股动脉血管瘘取血, RP-HPLC法测定血浆中游离氨基酸含量。结果表明,高精料组山羊乳中乳蛋白含量显著低于低精料组(P<0.05);肝门静脉血液中各游离氨基酸含量均高于低精料组,而肝静脉和股动脉血液中各游离氨基酸含量均低于低精料组,即高精料组各游离氨基酸在肝脏中的消耗量均多于低精料组,通过股动脉进入乳腺组织的氨基酸含量也少于低精料组。本研究结果显示,长期饲喂高精料日粮,乳蛋白含量降低。其机制与肝脏中氨基酸分配与重分配发生改变,氨基酸在肝脏中消耗量增大,进入乳腺组织合成乳蛋白的前体物氨基酸减少有关。  相似文献   

12.
We measured the plasma levels of amino acids at various reproductive stages in female rats, including the estrous cycle, pregnancy and lactation, and compared the resulting amino acid profiles using two- or three-dimensional figures. These figures revealed that the amino acid profiles of pregnant and lactating dams differed considerably from those during the estrous cycle or in male rats. The plasma levels of individual amino acids were almost the same between proestrus, estrus, metestrus and diestrus, and their profiles did not differ significantly. However, the amino acid profiles changed during pregnancy and lactation in dams. The plasma Ser level decreased significantly in mid and late pregnancy, whereas Tyr, Gly and His decreased significantly in the late and end stages of pregnancy, and Trp and Lys significantly decreased and increased at the end of pregnancy, respectively. Much larger changes in amino acid profiles were observed during lactation, when the levels of many amino acids increased significantly, and none showed a significant decrease. Plasma Pro, Ser and Gly levels increased continuously from day 1 until day 15 of lactation, whereas Asn and Met increased significantly from days 1 and 5 respectively until the end of lactation. These results suggest that the profiles of plasma amino acids show characteristic changes according to reproductive stage and that it may be necessary to consider such differences when performing amino acid-based diagnosis.  相似文献   

13.
The effects of adding lysine and/or methionine to a ration of calculated deficiency in these amino acids of 10% and 20%, respectively, were studied in 24 Brown Swiss cows. The mixed rations (27% grass silage, 19% maize silage, 5% hay and 49% concentrate on DM basis) contained 14.5% CP on average. Lysine supply was selectively elevated by adding fish meal in exchange for other concentrate ingredients. Methionine was supplied in a rumen-protected form. Milk protein content was elevated whereas fat amount decreased by adding both amino acids. Lactose content increased without additional lysine from fish meal. Live weight, milk yield, milk fat content and protein amount remained unaffected by any variation of amino acids supply. Also nutrient digestibility and nitrogen balance were not changed by the treatments. Blood plasma concentrations confirmed the assumed variation in metabolic lysine and, less clear, methionine supply. Effects on plasma concentrations of other amino acids were relatively small. Most plasma hormones and enzymes, and metabolites in plasma, urine and milk did not respond to the variation in amino acid supply. Lysine addition via fish meal increased aspartate amino transferase and decreased urinary allantoin concentration. Additional methionine elevated plasma ornithine. Overall lysine and methionine appear to have been only marginally deficient in the unsupplemented ration fed for 3 weeks despite the deficiency of 10% to 20% as calculated by the I.N.R.A. method.  相似文献   

14.
BACKGROUND: The concentration of free hemoglobin (Hgb) in plasma can markedly affect the outcome of laboratory tests by interfering with the spectrophotometric absorbance of biochemical tests read at wavelengths within the absorbance range of Hgb (400-440 nm). Little is known about the effects of hemoglobinemia on antithrombin (AT) activity in human plasma samples, and we are unaware of data for canine plasma samples. OBJECTIVES: The objective of this study was to determine the degree of interference by Hgb on plasma AT activity and to determine if the interference is proportional to the concentration of plasma Hgb. METHODS: Two pools of test plasma, designated AT100 and AT70, were prepared. Hemolysate was prepared by washing and freeze-thawing packed red cells in a small volume of saline, followed by collection of the filtrate. Solutions of decreasing Hgb concentration were prepared and added to the test plasma pools to create a series of samples with final calculated and measured Hgb concentrations of 0, 0.5, 1.5, 2.5, 3.5, 4.5, and 5.5 g/L. AT activity, expressed as a percentage of normal human plasma, was determined using a functional chromogenic assay. RESULTS: Increasing concentrations of Hgb resulted in a linear decrease in AT activity. Using linear regression analysis on the 70% and 100% plasma pools, the slopes for samples containing <1.5 g Hgb/L were not significantly different from zero. Slopes for samples containing Hgb concentrations >or=1.5 g/L were significantly (P > .0001) different from zero for both plasma pools, indicating interference with the assay. CONCLUSIONS: The results of this study suggest it may be possible, using a conversion equation, to accurately determine AT activity in hemolyzed samples, facilitating evaluation of coagulation status in patients with intravascular hemolysis.  相似文献   

15.
Five ram lambs (average body mass: 25 kg) were given, through a catheter inserted into the left ruminal vein, a total of 28.8 mM sodium acetate, 14.4 mM sodium propionate and 4.8 mM sodium butyrate per kg body mass as a 2-hour infusion. During and at 0, 1, 2, 4, 6, 10 and 24 h after the infusion blood samples were taken from the jugular vein and the blood plasma was assayed for free amino acid (FAA) and immunoreactive insulin (IRI) concentrations. Volatile fatty acid (VFA) infusion significantly decreased the blood plasma concentrations of all FAA but cystine. The lowest FAA concentrations were measured in plasma samples taken at the end of the 2-h infusion. Subsequently the level of all amino acids rose and by 24 h after the infusion the blood plasma concentration of all FAA came close to the preinfusion value. The largest differences were observed in the concentration of glutamate, glycine, leucine and isoleucine. In contrast to FAA, IRI concentration was increased significantly (almost fivefold) by VFA infusion. By 10 h after the infusion IRI concentration returned to the initial level. The results reported here indicate that energy supply given in the form of VFA infusion significantly affects blood plasma FAA profiles, supposedly as a result of changes induced in protein synthesis in tissues. Insulin presumably plays a role in the regulation of these changes.  相似文献   

16.
The aim of the study was to determine if differences in the molecular size of two protein sources affect in vivo intestinal absorption rates of amino acids under normal feeding conditions. Accordingly, the portal absorption rate of amino acids was studied in rats fed semi‐synthetic diets containing native casein (NC) or enzymatically hydrolysed casein as the only protein sources. Enzymatic casein hydrolysate (ECH) consisted of a mixture of free amino acids (51.2% with respect to total amino acids) and low molecular weight peptides. Rats were pre‐adapted to the experimental diets for 5 days prior to the absorption studies. Total free amino acid concentrations in portal vein plasma of rats fed ECH diet at 60, 105, 150 and 195 min after feeding were lower (p < 0.05) than those of rats fed NC. Lower (p < 0.05) concentrations of free threonine, proline, tyrosine, valine and tryptophan at all time points, and higher (p < 0.05) leucine at 60 and 105 min were found in rats fed ECH when compared with those fed NC in portal vein plasma. Portal flow rates of threonine, proline, tyrosine and valine were higher in NC at most time points tested, while leucine and lysine were higher for ECH fed rats 60 and 105 min after feeding. In arterial plasma, significantly (p < 0.05) higher concentrations of some individual free amino acids (proline, tyrosine, valine and tryptophan) were determined at 60, 105, 150 and 195 min after feeding, and lower leucine values after 60 and 105 min, in rats fed NC compared with those fed ECH. Results indicate that in normal feeding conditions amino acids from NC and ECH are absorbed at different rates in rats.  相似文献   

17.
Amino acid profiles and serum albumin and serum total protein concentrations were evaluated in dogs with renal disease. Nine dogs ranging in age from 1 to 15 years were identified as having mild to moderate chronic renal failure (CRF; exogenous creatinine clearance, 0.5 to 2.13 ml/kg of body weight/min). These dogs and a group of 10 clinically normal control dogs were fed a diet containing 31% protein for 8 weeks, at which time serum and urine amino acid assays and clearance studies were performed. All dogs then were fed a diet containing 16% protein for 8 weeks and then reevaluated. Chronic renal failure was associated with mild abnormalities in serum concentrations of amino acids. When fed the higher protein diet, dogs with CRF had lower serum concentrations of glutamine, leucine, proline, and serine and higher serum concentrations of cystathionine and 3-methylhistidine than clinically normal control dogs. When fed the low protein diet, dogs with CRF had lower serum serine concentrations and higher serum concentrations of cystathionine, phenylalanine, and 3-methylhistidine. Urine excretion of amino acids in all dogs on both diets was low, and dogs with CRF had lower renal clearances of 3-methylhistidine than control dogs. There were no significant differences in concentrations of serum albumin and total solids between either group, regardless of diet. We concluded that dogs with mild to moderately severe CRF have mild abnormalities of serum free amino acid concentrations, but renal conservation of essential amino acids is not impaired.  相似文献   

18.
It is well known that in protein‐starved chickens, small amounts of amino acid supplement, especially methionine, reduces nitrogen excretion and thereby improves nitrogen balance. On the other hand, excess intake of methionine causes growth depression and the growth‐depressive effect of excess methionine can be alleviated by consumption of dietary glycine. Insulin‐like growth factor‐I (IGF‐I) is one of various growth‐promoting factors relating to the efficiency of animal production and is known to be very sensitive to changes in nutritional status. In the present study, the interactive effect of glycine on nitrogen sparing effect of methionine in protein‐starved chickens was examined. In addition, the relation of IGF‐I and its specific binding protein to the nitrogen sparing effect of supplemented methionine was also investigated. Two‐days refeeding of methionine supplemented to protein‐free diet could promptly alleviate body weight loss in protein‐starved chickens, and the alleviation of body weight loss by methionine was not improved by glycine supplements. Moreover, such acute alleviation of body weight loss by dietary methionine was independent of the change in plasma IGF‐I concentration.  相似文献   

19.
The consumption of poultry meats exceeds 50% of total meat consumption. With the outbreak of bovine spongiform encephalopathy and foot and mouth disease, the consumption of poultry meat is set to increase. The use of meat bone meal derived from cattle and pigs is prohibited. Therefore, plant protein has to be used more frequently and the importance of the study of amino acid nutrition is increasing. In order to improve dietary efficiency, it is necessary to elucidate the exact amino acid requirements of poultry. The amino acid requirements are not constant and are affected by various factors. By using the plasma amino acid concentration as a parameter, it is possible to predict the amino acid requirements within a short period using a small number of animals repeatedly. By satisfying the amino acid requirements through supplementing crystalline amino acids, it is possible to reduce dietary protein and excretory nitrogen simultaneously. However, when the dietary protein is reduced, the abdominal fat tends to increase. This is solved by deciding the optimum dietary protein level, but it is difficult to control the taste of poultry meat by dietary amino acids.  相似文献   

20.
The influence of fetal plasma substrate and insulin concentrations on the fractional synthesis rate or turnover of the mixed proteins in the organs of fetal lambs was calculated from measurements of the rate of uptake of L-14C lysine by the protein in the steady state in utero. The control values for protein synthesis rate in the fetal organs of Welsh mountain ewes, 130 to 140 days' pregnant, were similar to those previously observed in the fetuses of Border Leicester ewes: the mean turnover rates were 38, 72, 40 and 63 per cent per day for the brain, liver, cardiac muscle and the placenta respectively; that for skeletal muscles was 6.8 per cent per day; the corresponding half lives were 2.15, 1.27, 1.8 and 1.42 days respectively and 11.3 days for skeletal muscle. A fivefold increase in the plasma glucose levels had no influence on protein turnover rate over a six hour period. A fourfold increase in the concentration of some amino acids, following a mixed infusion, decreased turnover rate in brain, heart and liver. The half life was increased by 30 per cent, but a small reduction in half life was observed in skeletal muscle. Insulin caused a fall in intracellular lysine concentration in skeletal muscle and in plasma, which suggests that the hormone can reduce muscle protein catabolism in the fetal lamb in the last trimester of gestation. Enhancement of synthesis rate occurred in the presence of the amino acid infusions only; the half life of the proteins was reduced by a factor of three. Insulin also increased placental protein synthesis rate by 50 per cent but had no influence on the other tissues studied.  相似文献   

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