15N-labeled lysine in colostomized laying hens. 5. 15N incorporation into blood fractions and the gastrointestinal tract

In the metabolism experiment three colostomized laying hens received, together with a commercial ration of 120 g, 0,2% 15N-labelled L-lysine with an atom-% 15N-excess (15N') of 48%; subsequently the same ration was fed over a period of 4 days with 0.2% unlabelled L-lysine. After the end of the experiment the hens were slaughtered. The atom-% 15N' was determined in total, in the lysine, histidine and arginine N in the corpuscles, the plasma, the NPN-fraction of the blood in the stomachs, the small intestine, the caecum and the rectum. 15N' in the corpuscles was 0.11 atom-%, in the blood plasma 0.17 atom-%, in the NPN-fraction of the blood 0.09 atom-%, in the tissue of the gastro-intestinal tract 0.11 atom-% and in its contents 0,12 atom-%. On average the blood contained per hen 77.9% lysine-15N', 16.4% arginine-15N' and 5.7% histidine-15N' of the basic amino acid-15N'. For the gastro-intestinal tract 78.7% lysine-15N', 19.0% arginine-15N' and 2.3% histidine-15N' of the 15N' of the basic amino acids were ascertained. In comparison to histidine the alpha-amino-N of lysine is incorporated to a considerably higher degree into arginine. For lysine and arginine the atom-% 15N' in the contents of the gastro-intestinal tract for days after the end of the supplementation of labelled lysine is between 8 and 10 times higher than in the feces of the last day of the experiment. This indicates a considerable secretion of the two amino acids in the gastro-intestinal tract and their re-absorption to a large extent.     

Dynamics of amino acid and protein metabolism in laying hens after the administration of 15N-labeled wheat protein. 2. 15N excretion with nitrogen and basic amino acids of the feces

Over 4 days 12 colostomized laying hens received together with a commercial ration labelled wheat with a 15N excess (15N') of 14.37 atom-%. The labelling of the basic amino acids amounted to 13.58 atom-% for lysine, to 14.38 atom-% for histidine and to 13.63 atom-% 15N' for arginine. 3 animals each were butchered 12 h, 36 h, 60 h and 108 h resp. after the last application of 15N. The heavy nitrogen in the total N and in the N fraction of non-protein origin as well as in the basic amino acids in faeces was daily determined for the individual hens in the total experimental period. On average the crude protein of faeces contained 5.45 % lysine, 2.32% histidine histidine and 3.68% arginine: the protein of faeces correspondingly contained 5.43% lysine, 2.32% histidine and 4.07% arginine. The quota of TCA soluble N in the total N of faeces amounts to one third on the 3rd und 4th days of the experiment and that of 15N' to 28%. The average atom-% 15N' of the protein fraction is 3.48 atom-% 15N' and that of the non-protein N fraction of faeces 2.93 atom-% 15N'. The apparent digestibility and that of the non-protein N fraction of faeces 2.93 atom-% 15N'. The apparent digestibility of the 14N of the ration on average amounts to 82.8% and that of the wheat 15N' to 87.5%. The average quota of the basic amino acids in the protein compounds of faeces amounts to 70.9% for lysine 15N', 73.7% for histidine 15N' and 70.3% for arginine 15N'. The digestibility of the 15N labelled amino acids amounts to 80.4% for lysine, 90.8% for histidine and 90.2% for arginine.     

The substitution of lysine supplemented high protein wheat for protein feeds during the rearing and laying periods of hens. 8. Nitrogen excretion and true amino acid digestibility as an effect of various lysine levels and successive laying periods]

Digestibility trials were performed with laying hens receiving 3 types of rations containing equal proportions of the same dietary components. The percentage of high-protein wheat in these rations was 74%. Ration I was supplemented with 0.12% lysine while 0.06% lysine was added to ration II; ration III remained unsupplemented. The crude protein content of rations 1 to 3 was 16.1%, 16.5% and 16.6%, respectively. The corresponding lysine percentages were 0.66, 0.62 and 0.56. Studies were made to investigate the influence of different lysine levels on the rate of N excretion and various amino acid data. These studies were carried out during two successive laying periods. Only random differences between the data for urinary N excretion and N balances per kg liveweight were obtained in the two laying periods and for the different lysine levels. The true lysine digestibility was significantly lower in the poor-lysine ration as compared with the ration with 0.66% lysine. Moreover, the absorptive capacity for thio-amino acids is influenced by the lysine level of the ration. The proportion of lysine contained in faecal crude protein increased with the decreasing lysine content of the ration. Similarly, the total number of amino acids present in faecal crude protein increased with the declining supply of lysine. These findings suggest that relatively more NPN compounds are excreted in the faeces if adequate amounts of amino acids are supplied rather than when one amino acid is deficient.     

The effect of straw meal on the crude protein and amino acid metabolism and the digestibility of crude nutrients in broiler breeding hens. 3. Digestibility of amino acids

In two experiments with colostomized broiler hens the influence of a straw meal supplement on the apparent digestibility of the amino acids of the ration and the 15N labelled basic amino acids in wheat was studied. In experiment 1 the animals received 120 g mixed feed plus 0, 20, 30 and 40 g straw meal per animal and day. The digestibility of the amino acids decreased on average from 86% to 83%, 80% and 79% with the growing straw intake. In contrast to the control variant, 20 g straw meal intake resulted in a significant decrease of digestibility for lysine, histidine, glycine, tyrosine, phenylalanine, cystine and methionine. 30 and 40 g straw meal reduced significantly the digestibility of all amino acids with the exception of arginine. The amino acid composition of the crude protein in faeces changed only very slightly due to the straw supplement. In experiment 2 15N labelled wheat was a component of the ration. Of the 15N labelled amino acids lysine, histidine and arginine, 88, 90 and 95% were apparently digested. The adaptation of the animals to straw meal intake did not change the digestibility of the amino acids.     

The substitution of protein feed by lysine supplemented protein-rich wheat during the raising and laying periods of hens. 7. Report. Determination of the true digestibility of amino acids with and without lysine supplement in the feed]

In the present paper regression techniques were used for determing the true digestibility of amino acids from lysine-supplemented rations fed to laying hens as compared with unsupplemented rations of the same composition. 5 groups of 4 hens each were investigated receiving graded amounts of food and nutrients. The daily amounts of pellets fed per bird in group 1 to 5 were 120 gms, 100 gms, 80 gms, 60 gms and 40 gms. The quantity of lysine contained in 100 gms of the pellets was 664 mg in ration 1 and 554 mg in ration 2, the corresponding N values being 2.57 gm and 2.62 mg. The total amount of endogenic amino acids excreted per day was 128 mg per kg of body weight in birds receiving the lysine-supplemented ration and 132 mg per kg of body weight for the lysine-deficient ration. Data for the true digestibility of lysine and isoleucine were significantly higher in the case of the lysine-supplemented ration than with the lysine-deficient mixture. Lysine values were 86% and 75%, the corresponding lysine data in crude faecal proteins 4.8% and 7.1%. Generally speaking, the crude faecal protein of hens fed the lysine-deficient diet contained higher proportions of most of the essential and non-essential amino acids.     

Studies on the protein and amino-acid metabolism of laying hens using 15N-labelled casein. 15N-incorporation into N-fractions and amino acids of various parts of the body

Four colostomized Leghorn hens were fed, during 6 days, 15N-labelled casein as sole protein source. Two animals were slaughtered 48 hours, the other two 144 hours after the last 15N-application. The share of TCE-soluble N in total N averaged 16% for the body parts analysed, i.e. meat, bone, liver, kidneys, oviducts, residual viscera and other. The variation of the lysine, histidine and arginine levels in the body parts ranged from 3.6 to 7.9 g, 1.1. to 3.7 g and 6.4 to 7.4 g in 16.7 g hydrolysate N, respectively. Except for feathers, the analysed body parts contained and excess amount of heavy nitrogen. The degree of labelling was found to depend on the time of slaughtering after the tracer application. In the liver and in the oviduct being metabolically active organs, the 15N-excess in the total N fraction decreased by 45% between the 2nd and the 6th days after 15N-feeding, whilst in the meat it went down by 20%. The decline of the 15N-concentration in the TCE-soluble N compounds was faster than in the total N-fraction. Out of the body samples analysed, the lysine of the liver having 0.26 atom % 15N-excess was found to be more strongly labelled in hens 1 and 2. The amino acid arginine reached about the same level of labelling, the 15N-frequency of histidine being the lowest.     

Metabolism of colostomized laying hens with 15N-labeled wheat. 3. Incorporation of 15N into and its distribution over follicles of various stages of development, the restovar and the oviduct

Of colostomised hens fed with labelled wheat protein the atom-% 15N-excess (15N') was ascertained in the bigger follicles, the restovar and the oviduct from the total N, the lysine-N, histidine-N and arginine-N. The labelling of the basic amino acids decreases the smaller the follicles are. In contrast to the yolk, in which a constant relation between the three amino acids was found, the relations were inconsistent and typical of the individual hens. In the atom-% 15N' in the three amino acids in the restovar and the oviduct there were greater differences between the hens. In the lysine, histidine and arginine we found, on an average, 21.2% of the total labelled N of the follicles.     

Metabolism of colostomized laying hens with 15N-labeled wheat. 2. Incorporation of the labeled nitrogen into fractions of the egg]

The colostomised hens received 15N-labelled wheat. For a period of 8 days the incorporation of the 15N excess (15N') into the albumen, the yolk and the egg-shell was measured. In addition to that, the values for atom-percent of 15N' in the amino acids lysine, histidien and arginine of the albumen and the yolk were ascertained. The egg-shell and the albumen were labelled shortly after the beginning of the experiment. In both fractions the atom-per cent of 15N' rises more quickly than in the yolk. After the withdrawal of the labelled feed the decrease in the yolk was slower than in the egg-shell and the albumen. Concerning the atom-per cent of 15N' there is hardly a difference between the total N and the amino acids. Despite the different supply with amino acids, the relation of histidine 15N' : lysine 15N' : arginine-15N' in the yolk and the albumen remains largely constant. It is 1 : 2 : 3 and corresponds to the quantitative relation of the N content of the three amino acids in the egg protein. The utilisation of 14N and 15N' of the wheat lysin for the egg synthesis amounts to approximately 50%. There are considerable differences between the utilisation of 15N' of the histidine and 15N' of the arginine and the 14N of the two dietary amino acids.     

Dynamics of amino acid and protein metabolism of laying hens after administration of 15N-labeled wheat protein. 5. Incorporation of 15N into the blood fraction and its amino acids

12 colostomized laying hens which received 15N labelled wheat over 4 days were butchered 12 h, 36 h, 60 h and 108 h (3 animals each) after the last 15N application. The intake of 15N excess (15N') from the wheat amounted to 540 mg 15N' during the application period. The 15N' in the blood plasma decreased after the last 15N' application from 0.76 atom-% to 0.55 atom-% after 108 h, the labelling of the corpuscular components at the same measuring points increased from 0.28 to 0.50 atom-% 15N'. 96.6% of the plasma 15N' and 93.8% of that in the corpuscles is precipitable in trichloric acetic acid. The atom-% 15N' of histidine in the total blood remained unchanged in dependence on the butchering time. The 15N amount in lysine and arginine and that in the non-basic amino acids decreased inconsiderably in the period between 12 h and 108 h after the last 15N' wheat feeding.     

The substitution of protein feed by lysine supplemented high protein wheat during the rearing and laying period in hens. 9. True amino acid digestibility of rations with varying lysine levels in hens who had a colostomy]

24 experimental birds were fed the same basal ration containing 74% high-protein wheat, 4% extracted soya bean meal, 7% extracted groundnut meal, 2% feed yeast, 1.75% dried green meal, 1.25% mixed vitamins and 10% of a mineral mixture. The birds were placed in 4 groups each comprising 6 hens. The first two groups received an optimum of lysine (0.68%) added to the ration. The rations for the two other groups contained 0.55% lysine. 6 birds of each group receiving either the lysinesupplemented or the unsupplemented rations were colostomated to investigate in which way the hydrolysed urine would affect the true amino acid digestibility. 8.3% of urinary N from the total amount of faecal N were precipitated as uranyl acetate in the faeces of hens fed the lysine-supplemented ration as compared with 7.3% urinary N in birds receiving the unsupplemented ration. The corresponding figures for non-precipitable faecal N were 8.9% and 8.2%. A comparison was made between the levels of amino acids excreted by colostomated and non-colostomated hens showing that 12.4% +/- 3% and 11.7% +/- 3% more amino acids (figures for the supplemented and unsupplemented rations) were excreted in the presence of urine. On the basis of these results the authors recommend that only colostomated hens should be used in digestibility and total metabolism trials.     

Effects of excess arginine with and without supplemental lysine on performance, plasma amino acid concentrations and nitrogen balance of young swine

Three experiments were conducted to determine the effects of excess arginine on performance, plasma amino acid levels and N balance of young pigs (initial weights 6.9, 7.0 and 10.3 kg, respectively). In a 28-d growth trial, various amounts of arginine (0 to 1.6%) were added to a conventional starter diet. Addition of arginine decreased (P less than .01) average daily feed intake (ADFI) and gain (ADG), but had no effect on feed efficiency (G/F). Plasma urea, arginine and ornithine concentrations were elevated (P less than .001) by the increasing dietary arginine levels at d 14 and 28. Plasma histidine levels were reduced (P less than .01) at d 28. Plasma lysine levels exhibited a cubic response (P less than .05) at d 14, but were not affected by excess arginine at d 28. In a second growth trial ADFI and ADG were decreased (P less than .05), but G/F was not affected by the addition of 1.6% dietary arginine. Lysine supplementation (0, .15 or .30%) increased performance in the absence of excess arginine, but the main effect of lysine was not significant for any performance criteria. As in the first experiment, plasma concentrations of urea, arginine and ornithine were increased (P less than .001) by the addition of arginine. Plasma histidine was not affected by either arginine or lysine. Plasma lysine levels were reduced (P less than .001) by dietary arginine and increased (P less than .001) by lysine. In a N balance experiment, addition of 1.6% dietary arginine increased N digestibility, but decreased apparent biological value. Nitrogen balance was not affected by added arginine. Lysine addition did not improve any of these three indices of N utilization. The inability of lysine supplementation to alleviate any of the adverse effects of excess arginine in young swine indicates that the reduced performance is caused by a generalized amino acid imbalance, and not by a specific interference with lysine utilization in the manner of a classical arginine-lysine antagonism.     

Vitamin E requirement of chicks and young hens

In 4 experiments young chickens of the species White Leghorn received semisynthetic rations with a vitamin E content less than 1 mg/kg basal ration. Sunflower oil heated with FeCl3 supplement was used as a factor increasing requirement. Feed intake, live weight gain and feed expenditure with semisynthetic rations without oil supplements did not depend on vitamin E supplements. After the feeding of rations without vitamin E animal losses were higher. The losses were normalized by 1 mg vitamin E supplement per kg feed. Rations containing sunflower oil without vitamin E supplementation resulted in encephalomalacia of the young chickens. Vitamin deficiency increased triiodine thyronine content in the blood plasma. Antibody formation after the application of human gamma globulin did not depend on the vitamin E supply studied. A vitamin E requirement of young chickens and young hens of the laying species of less than 1 mg/kg mixed feed is derived from the results.     

Substitution of protein feed through lysine-supplemented high-protein wheat during the rearing and laying period of hens. 4. Effect of graded lysine doses during the rearing of young hens on the performance characteristics during the laying period]

1530 laying hybrid hens kept under conditions of large-scale production were used to test whether varying lysine levels given to young hens would later on influence the production of the birds during their laying period. Thus, young hens received isonitrogenous and isocaloric diets with varying lysine content (group 1-4: 0.59%, 0.61%, 0.54%, 0.46%) and varying sources of lysine (group 1: wheat/fish meal; group 2--4: wheat/synthetic L-lysine). The ration used for the controls was prepared on the basis of nationally prescribed formulas.     

Low protein rations based on wheat and soybean meal or corn and soybean meal for laying hens 1

Rations in which all the protein was supplied by wheat and soybean meal or corn and soybean meal were fed to White Leghorn hens for 252 d. Rations based on wheat‐soybean meal which contained 14% protein supported a high and efficient rate of egg production when supplemented with sufficient lysine and methionine to ensure minimum intakes of 600 and 300 mg per hen‐day, respectively. Similarly, corn‐soybean meal rations which contained 12 to 14% protein and were properly supplemented with methionine and lysine supported satisfactory laying hen performance. Average egg size of hens fed on rations based on wheat was slightly smaller than that of hens fed on corn‐based rations. Lysine supplementation did not alleviate this.

The data re‐emphasise that protein concentration of laying hen rations can be reduced from the commonly used 15.5 and 16.5% levels to 14% without impairing productive performance, provided that rations based on wheat and soybean meal or corn and soybean meal are supplemented judiciously with lysine and/or methionine.     

Long‐term feeding effects of dietary protein levels on egg production,immunocompetence and plasma amino acids of laying hens in subtropical condition

The objective of this study was to determine the effect of protein levels on production performance, immune response, liver triglyceride and plasma amino acids profile of laying hens during 21–48 weeks of age. Two groups of commercial hens (Babcock B‐308) were fed with diets with different crude protein levels (14% and 18% CP). The high protein diet (18% CP) significantly increased production performance, essential amino acid intake, spleen weight (% of body weight), ND‐titre (haemagglutination‐inhibition test), serum albumin (g/dl), serum alpha‐globulin and plasma essential amino acids (except histidine) and decreased liver triglyceride (mg/g liver) in relation to the low protein diet (14% CP). In long‐term effect, therefore, this study suggested that adequate dietary condition of amino acids, particularly methionine and branch‐chain amino acids is necessary for sustaining normal immunocompetence and achieving maximum production performance.     

Utilization of 15N-labeled urea in laying hens. 9. Bones, feathers and 15N-incorporation in the rest of the body

For studying the incorporation of the 15N labelled urea into individual organs and tissues 3 colostomized laying hens were butchered after they had received 1% urea (96.06 atom-% 15N excess) with a high quality ration over a period of six days and after receiving conventional urea for another two days. Nitrogen and atom-% 15N excess (15N') were determined in the bones, the feathers and the remaining body (skin, lungs and windpipe, head with comb and wattle, lower leg without bones and with skin, pancreas and fatty tissue). In the remaining body the atom-% 15N' was determined in 15 amino acids. The labelling in the remaining body and the bones was approximately the same and averaged 0.37 atom-% 15N'. A significantly lower relative frequency could be detected in the feathers. The lysine of the remaining body contained only 0.04 atom-% 15N', tyrosine 0.06, histidine and arginine 0.07. The phenylalanine and proline molecules were labelled with 0.11 atom-% 15N'. Most 15N' was incorporated in serine and glutamic acid with over 0.30 atom-%. In the six non-essential amino acids out of the 15 amino acids studied, 48.6 of the non isotopic nitrogen of the total N of the remaining body and 70.7% of the isotopic nitrogen of total 15N' could be detected. Consequently the urea-N is mainly used for the synthesis of the non-essential amino acids, with its utilization being very low.     

The metabolism of colostomised laying hens with 15N-labelled wheat. 4. 15N-Incorporation in the corpuscular components of blood, in the blood plasma and the basic amino acids]

Three colostomised Laying hybrids received over four days a dosage of 672 mg 15N-excess (15N'), 20.3 mg lysine 15N', 23.0 mg histidine-15N' and 66.7 mg arginine-15N' with a ration customary in production. After feeding the same nonlabelled ration for another four days the hens were killed and the N-content of the blood as well as of its fractions (corpuscular components, plasma, free amino acids of the plasma) was determined.     

Some effects of protein deficiency in young growing pigs. II. Blood plasma free amino acids

The influence of protein deficiency, rehabilitation and total starvation on the free amino acid levels in the blood plasma of pigs has been investigated. It was found that the concentration of most amino acids was reduced during protein deficiency. The levels of leucine, isoleucine and valine were diminished by the greatest proportion, followed by threonine, tyrosine and citrulline. During the first few weeks of protein deficiency the levels of lysine, histidine and arginine were slightly increased, but later decreased below control values. Concentrations of glycine and alanine were altered in a similar way except that the initial increase was much more pronounced. The concentrations of most of these amino acids returned to control levels after rehabilitation. Total starvation led to an increase in concentration of leucine, isoleucine, valine, threonine and to a smaller extent phenylalanine, lysine, citrulline and arginine. The concentration of glycine, alanine and glutamic acid were very much reduced. The level of urea in the circulation dropped reversibly during protein deficiency and increased very much during total starvation.     

The effect of a single oral dose of lysine or arginine on the excretion of free amino acids by the starved laying hen

The excretion of free amino acids by laying hens was measured during the period 0 to 5 h after the oral administration of 0.1 g lysine HCl or 0.1 g arginine HCl.

Lysine administration resulted in a significant increase in the excretion (μmoles) of arginine (6.8 to 25.9), ornithine (5.8 to 39.3) and tyrosine (3.2 to 5.1) while arginine administration resulted in a significant increase in the excretion (μmoles) of lysine (6.8 to 93.0), ornithine (4.1 to 71.9), tyrosine (2.3 to 5.5), histidine (10.8 to 88.3), threonine (16.8 to 33.3), serine (22.7 to 34.0) and glycine (17.3 to 56.3). The effect of arginine administration on lysine excretion was significantly greater than that of lysine on arginine excretion (P < 0.01).

In the lysine experiment the overall pattern of changes in the hourly excretion rate of the affected amino acids was the same as that of administered lysine. The maximum hourly excretion rate of administered arginine occurred one hour earlier than the maximum for the amino acids affected by administered arginine.

It is suggested that arginine may alleviate certain dietary amino acid excesses by increasing the excretion of that amino acid which is in excess.     

Protein digestibility and absorption of amino acids in various segments of the digestive tract of pigs. 2. Protein and amino acid balances at the end of the small intestine and of the whole digestive tract (apparent and true protein and amino acid digestibility)]

Growing pigs with ileum and ileocecal re-entrant canulae were given 5 different rations (pig fattening feed 1 and 2, rations with dried skim milk, wheat gluten + lysine and wheat + wheat gluten + lysine). The crude protein and amino acid excretion was quantitatively determined with ileum chyme and feces. The calculation of the amino acid balances (apparent and true digestibility) at the end of the small intestine, at the end of the wholedigestive tract and the isolated colon showed characteristic differences for the individual amino acids. On ileum level the amino acids with relatively high endogenous quotas, threonine, tryptophane, alanine, aspartic acid and glycine showed a distinctly lower, the amino acids arginine, methionine, phenylalanine, glutamic acid, proline and tyrosine a distinctly higher digestibilityhan crude protein. In comparison of the values on the feces level, including the true digestibility, these differences are largely balanced out. At the end of the small intestine the absorption of the amino acids is in the main completed. The disappearance rate of amino acids from the colon shows large differences with reference to the different rations as well as the individual amino acids. They were particularly high for various rations as far as proline, tryptophane, glycine and cystine are concerned. If wheat gluten + lysine rations were given, a net synthesis of methionine in the colon could be proved.