Amino Acid Nitrogen Content Research Articles

Effect of a commercial enzyme preparation on alfalfa silage fermentation and protein degradability

A commercial enzyme preparation (trade name Clampzyme) containing cellulases, hemicellulases and glucose oxidases was tested for ensiling of alfalfa at three dry matter levels, 16% and 22% unwilted and 28% wilted, in comparison with untreated control and formic acid treated silages. On average the enzyme-treated silages hd a lower pH (by 14.6% at P = 0.000), lower crude fibre content (by 16.0% at P = 0.000) and ammonia concentration (by 20.3% at P = 0.017), and higher water-soluble carbohydrates (by 115% at P = 0.000) and crude protein (by 11.8% at P = 0.006) contein preservation, increasing the control. The enzyme treatment had an undesirable effect on the silage protein preservation, increasing the buffer soluble nitrogen (by 16.9% at P = 0.014) and the free amino acid nitrogen (by 25.5% at P = 0.007) content compared with the untreated control. The enzyme-treated silages tended to have lower trichloroacetic acid insoluble nitrogen (by 7.8% at P = 0.080) than the control. The degradability of the silage protein in vitro (4-h incubation) was higher (by 28.0% at P = 0.006) for the enzyme-treated silages compared with the control. The same trend was observed in sacco where the difference over the control silages decreased from 11.9% ( P = 0.001) at the 1 h to 8.2% ( P = 0.001) at 24 and 4.3% ( P = 0.001) at 48 h of rumen incubation. In these experiments no protective effect of the formic acid on silage protein degradability in vitro or in sacco was observed. In conclusion, the enzyme treatment had a positive effect on alfalfa silage fermentation, in particular on reducing the crude fibre content and preserving the soluble sugars. An increase in rumen degradability of the silage protein in vitro and in sacco was observed with the rapidly degradable fraction of the protein being the most affected.

Temporary storage compounds and sucrose‐starch metabolism in seed coats during pea seed development (Pisum sativum)

Quantitative data for growth, carbohydrate, protein and free amino acid nitrogen content of pea (Pisum sativum L. cv. Finale) seed coat were obtained during the main stage of seed development. These data allowed us to define the role of the seed coat storage compounds. High amounts of arginine were measured in the seed coat and this amino acid is hypothesized to be synthesized de novo in the seed coat cells. Starch appeared to be stored in a specific parenchyma layer of the seed coat. Starch storage was shown to occur from phloem‐unloaded sucrose and high activities of some enzymes of sucrose‐starch metabolism (sucrose synthase, EC 2.4.1.13 and ADP glucose pyrophosphorylase, EC 2.7.7.27) were measured. The contribution of seed storage compounds is discussed in terms of buffering embryo nutrition. The sink strength of the young pea seed may be located within the seed coat.

Untersuchungen zum ruminalen Stickstoffumsatz bei Kälbern und Schafen

In a model experiment with calves supplied with duodenal re-entrant and rumen fistula resp. rations were tested that were energetically different (535 and 585 EFU cattle/kg DM) due to changing quotas of wheat starch and straw resp., dry matter intake being equal, and in which 45% of the crude protein came from soybean oil meal or urea resp. Due to the N-equivalent exchange of soybean oil meal by urea in rations for ruminating calves (130th day of life) the ammonia-N content in the rumen fluid, the quota of bacteria-N in the duodenal non-ammonia N (NAN) as well as the fermentation of crude plant protein in the ration were clearly increased. The iso-acid content in the rumen fluid and the utilization of the N available for bacteria N synthesis (N intake minus not degraded feed N in the duodenum) were reduced. An influence on duodenal NAN passage, on the apparent fermentation of the organic matter, on postruminal NAN digestibility and on the content of amino acid nitrogen as well as the amino acid composition of duodenal NAN could not be proved. A ca. 20% higher energy intake by ruminating calves did not have a clear influence on other parameters, with the exception of the reduction of the molar quota of acetic acid in favour of the quota of propionic acid in the rumen fluid.

Changes in carbohydrate and nitrogenous components and amylase activities during germination of grain amaranth

Grain amaranth (Amaranthus hypochondriacus), Yercaud local variety, was soaked overnight and germinated for 192 h taking the soaked grains as the zero time (0 h) sample. The changes in the activities of alpha- and beta-amylases, starch, sugar, protein and lysine contents during germination are reported. Activity of alpha-amylase was high in the 0 h soaked grains, while beta-amylase activity was high in 72 h germinated grains. The joint action of the amylases resulted in a decrease of starch content from 0 to 192 h in germinated grains and an increase in total sugars during the initial period of germination. Protein nitrogen was found to decrease from 48 h to 192 h accompanied by an increase in free amino acid and non-protein nitrogen contents. Total lysine content was found to be increased by 31% in 24 h germinated grain amaranth. Protein fractionation of raw, soaked and 24 h germinated grain amaranth showed that the distribution of different types of proteins varied during germination of the grains. An increase of water soluble protein content was noticed in 24 h germinated grains.

Changes in plasma growth hormone and various metabolic factors during smoltification of coho salmon, Oncorhynchus kisutch

Plasma and tissue samples were collected weekly from juvenile coho salmon during the parr-smolt transformation as well as for an additional 12 weeks in freshwater during desmoltification. The parameters measured were: plasma growth hormone, muscle glycogen, liver glycogen, liver glucose, muscle protein, muscle amino acid nitrogen, and individual plasma saturated and unsaturated free fatty acids. Plasma levels of growth hormone increased over the sampling period. Muscle and liver glycogen decreased during smoltification but increased again over desmoltification. Liver free glucose was unchanged over the sampling period except for low levels seen over a 3-week period immediately following normal release from the hatchery. The ratio of liver free glucose to glycogen increased during smoltification and then decreased. Muscle protein levels were fairly stable over both smoltification and desmoltification. Amino acid nitrogen content of the muscle fluctuated weekly but generally increased over the latter weeks of the study. Both the saturated and unsaturated plasma free fatty acids remained stable initially, but increased dramatically near the end of the study. Correlations between the various parameters and plasma growth hormone are examined to ascertain possible roles of growth hormone in the physiology of the smoltification and desmoltification processes.

Influence of nitrogen fertilization on chemical composition of potato tubers

The present study is focused on the changes in chemical composition of potato tubers (14 varieties) affected by increased doses of nitrogen fertilizers. Intensified nitrogen fertilization decreased the content of dry matter and starch in potato tubers. Moreover, it increased nitrogen content in dry matter and in non-starch dry substance of the potato tubers. Nitrogen fertilization also increased the content of protein nitrogen in dry matter of potato tubers but decreased its contribution to total nitrogen. Nitrogen fertilization consequently increased the content of amide and amino acid nitrogen in potato dry matter and total nitrogen. Increased levels of nitrogen fertilizers were followed by an increase in amino acid content determined in the hydrolyzates of raw potato flesh. No effect of nitrogen fertilization on essential amino acids in conversion to crude protein has been observed.

Organic geochemistry of two 40-m sediment cores from the Gulf of Trieste (Northern Adriatic)

Sediment samples from two 40-m cores drilled in two different sedimentological environments in the Gulf of Trieste (Northern Adriatic), i.e. in the salt marsh of Sečovlje and in the inner part of the Bay of Koper, were taken for geochemical analysis of organic matter. The organic geochemical analysis comprised the analyses of organic carbon, nitrogen and phosphorus contents and the analyses of amino acid and hexosamine nitrogen and total carbohydrate contents in the samples. Parallel analyses of carbon and oxygen isotopic composition in calcite, and of the granulometric and mineralogical composition of the samples were performed. Depth variations of the distribution pattern of organic carbon, nitrogen, phosphorus, amino acids, hexosamines and carbohydrates in the cores indicate temporal variability of organic matter deposition and transformations in a changing fluvial-brackish-marine environment in the past. The results also provide information on paleoecological changes in the Gulf during Quaternary sedimentation processes. It appears that the marine environmental conditions in the past were not markedly different from those of the present day.

The Influence of Diet on Nitrogen and Amino Acid Content of Mixed Rumen Bacteria

Abstract Rumen bacteria were isolated from rumen fluid collected 3 hours after feeding from cows fed 24 different diets. The bacteria isolated were analysed for nitrogen and amino acid nitrogen (AA-N) content. The nitrogen content in the bacterial dry matter varied between 6.2% and 9.0% with a mean value of 7.8%. This variation could not be related to any dietary components analysed for. The proportion of AA-N in total bacterial nitrogen varied between 62.1% and 72.3% with a mean value of 67.4% and a significant relation was obtained both to the crude fibre and LHK (sugar + starch) content in the diets. The proportion of AA-N found in the bacteria is discussed in relation to the proportion of AA-N found in duodenal content in 18 published reports, and it is concluded that a proportion of AA-N in bacterial nitrogen of approximately 70% seems justified.

Effect of Herbicides on Chemical Composition of Potato Tubers and Quality of the Subsequent Chips and Starch

AbstractApplication of 6 different herbicides in potato cultivation resulted in changes of chemical composition of tubers, quality of chips and properties of starch. Sencor, Bladex, Topogard, Afalon and Aresin indicated rather unfavourable effects on chemical composition of the tubers. On one hand they increased the average weight of the tubers, on the other hand they decreased the dry matter (triazines) and starch content (Afalon). They increased the amount of reducing and total sugars (urea) and increased the content of amide nitrogen (triazines and Afalon) and amino acid nitrogen (Bladex). Sencor and Afalon resulted in darker colour of the chips. Afalon, Aresin and Chwastox increased the part of small granules or decreased the amount of large granules in the starch. Afalon and Bladex resulted in changes of phosphorus content, and Chwastox changed the amount of amylose in starch.

Variation of the legumin seed storage protein amongst Vicia species

Variation in legumin, the major seed storage protein of Vicia faba was investigated in different (primitive and cultivated) varieties of V. faba and in other primitive Vicia species. Qualitative variation in legumin subunit patterns on gel electrophoresis was less within the species V. faba than the variation between Vicia species. However, the large seeded modern V. faba cultivars showed much increased levels of the ‘main’ legumin subunit pairs. Analyses of amino acid composition, and nitrogen and sulphur content did not show systematic variation between the samples tested, and suggested that breeding and selection had not decreased protein content or nutritional quality. It was concluded that the heterogeneities of legumin genes in the Vicia species examined are comparable, and that selection for a large-seeded phenotype in V. faba has had the effect of increasing the expression of a subset of legumin genes, those encoding the ‘main’ subunit pairs.

Amino Acid Composition of the Plumage of the White-Crowned Sparrow

To provide baseline data for estimating the dietary amino acid requirements of molting birds, we measured the amino acid composition, nitrogen and sulfur content, and heat of combustion of the homogenized plumage of six White-crowned Sparrows (Zonotrichia leucophrys gambelil). On the average, the plumage contained 15.22% nitrogen, 3.14% sulfur, and 0.86% ash. Of the 17 amino acids measured, serine, proline, cystine/2, and glycine (in that order) were most abundant, comprising 46 mol% of the hydrolysate. Nonessential amino acids predominated (68 mol%). Cystine/2 contributed 11 mol%. Variation of amino acid composition among the plumages of the six birds was small (coefficient of variation = 2-7%). The heat of combustion of the homogenized plumages was 21.69 kJ/g of dry mass. Although exact quantitative comparisons are not possible, the amino acid composition of White-crowned Sparrow plumage in general parallels that of other species. Its cystine/2 and sulfur content, however, are noticeably greater than that reported for any other species thus far examined (primarily pale and domesticated). The quantities of exogenous nutrients required per unit time in the production of eggs, feathers, or tissues can be estimated from a knowledge of the growth rates and composition of the synthesized products. If either the ratio of calories to specific nutrients is low or the concentrations of dietary nutrients are much less than their concentrations in products, then an animal engaged in production must (1) eat in excess of caloric requirements in order to obtain adequate materials, (2) rely on endogenous materials, if available, or (3) alter the rate, timing, or pattern of production so that requirements match nutrient availability. Depending on circumstances, any or all of these adjustments might be invoked. In the case of avian molt, it has been noted that the amino acid cystine is much more concentrated in feathers than in the foods that many birds consume (Hanson 1962, Newton 1968, Gavrilov and Dolnik 1974). This has fostered hypotheses that attempt to relate energy requirements, feeding tactics, and alterations of body composition during molt to dietary cystine availability (Gavrilov and Dolnik 1974). The reliability of such hypotheses depends on accurate estimates of the cystine content of the entire plumage. Although this emphasis on cystine may be questionable, it is nevertheless necessary to know the amino acid composition of whole plumage before this or other hypotheses about amino acids as limiting factors during molt can be critically examined. Although there have been many analyses of the amino acid composition of single feathers, feather parts, and purified keratins (Block 1939, Ward and Lundgren 1954, Schroeder and Kay 1955, Harrap and Woods 1964, 1967, Kemp and Rogers 1972, O'Donnell and Inglis 1974, Busch and Brush 1979, Nitsan et al. 1981), none except the last has reported the average amino acid composition of an entire plumage. Also, nearly all of these analyses involved feathers from domesticated species of birds having white or near-white plumage. Because differences occur in the amino acid composition of feathers from different species as well as among feather parts from a single species (Schroeder and Kay 1955, Harrap and Woods 1964, 1967) extrapolations of percentage composition from purified keratins or feather parts to whole plumage or from one species to another might be tenuous. As we were reluctant, in nutritional investigations to be reported elsewhere, to depend on such extrapolations without testing their reliability, we undertook the following analysis. MATERIALS AND METHODS We sacrificed six White-crowned Sparrows (Zonotrichia leucophrys gambeli) captured during the autumn migration in eastern Washington and plucked all the feathers from them. We put the feathers from each bird into a loosely woven cloth bag and washed them according to the methods of Harrap and Woods (1964). We then macerated the air-dried feathers with shears until they formed a felt-like,

Potato composition: III. Tissue selection and its effects on total nitrogen, free amino acid nitrogen and enzyme activity (polyphenolase, monophenolase, peroxidase and catalase)

Russet Burbank, Norchip, Kennebec, White Rose, Red La Soda and Lenape tubers were sampled at harvest, after storage for 2 and 4 mo at 7 C, and after 3 wk at 20 C following each storage treatment. Freeze-dried tissue from the bud-end, stem-end and core was analyzed for total, and free amino acid nitrogen, and for monophenolase, polyphenolase, peroxidase, and catalase activities. Significant differences among cultivars and among different parts of the tuber were found for all nitrogen fractions and all enzyme activities. Storage treatments significantly changed the total and free amino acid nitrogen contents and polyphenolase, peroxidase, and catalase activities. When compared for total nitrogen content and catalase activity, differences among different parts of the tuber which were statistically significant were similar in all cultivars. However, when compared for free amino acid content, and monophenolase, polyphenolase and peroxidase activities, differences among different parts of the tuber which were statistically significant were dependent upon which cultivar was examined. The differences among cultivars which were statistically significant for all nitrogen fractions and all enzyme activities, except peroxidase, were not significantly changed by storage treatment. The differences among different parts of the tuber which were statistically significant for quantity of both nitrogen fractions and for all enzyme activities were not significantly changed by storage.

Air-Dry Tree Leaves for Use in a Restricted Dietary Regime

Extensive nutritive analyses were completed on air dry tree leaves (approximately 85% from oak trees) collected on the ground in October. The total essential amino acid composition of the leaves on an air dry basis (76.08% dry matter) was calculated to be about 72% of the total essential amino acid composition of corn. The amino acid nitrogen content of the leaves was about 93% of the amino acid nitrogen content of corn. The crude protein content of the leaves on a dry matter basis was 6.02%. Aluminum, iron and manganese were present at highest levels of the trace elements determined. The leaves contained 25.58% cellulose, 26.48% lignin and 2.42% hemicellulose.

Chemical methods suitable for screening for protein content and quality in cowpea (Vigna unguiculata) meals.

AbstractSeveral chemical methods have been tested for their suitability as screening procedures for estimation of the protein content and quality of cowpea (Vigna unguiculata) meals.Preliminary estimates of crude protein can be obtained by the UDY dye‐binding procedure, followed by the automated microKjeldahl (% N × 6.25) method using, for example, Carlo Erba equipment. Total amino acid nitrogen was estimated also with the Carlo Erba apparatus and for the cowpea varieties examined a positive correlation between the total amino acid nitrogen and total nitrogen contents was found. Total sulphur was evaluated as a measure of the sulpho‐amino acids in cowpea meals. Total sulphur was determined by wet digestion and subsequent turbidimetric estimation of barium sulphate. Methionine was determined in meal hydrolysates by a Locarte Autoanalyzer. Cysteine was determined either as cysteic acid on the Locarte Autoanalyzer or as bismuth sulphide.The results obtained for cowpea meals showed that there was a relatively small variation in the total sulphur and in the sulpho‐amino acid contents. Although the relation between total sulphur and sulpho‐amino acids was found to be significant at the 95% confidence level, the confidence limits were wide and at this stage a definite recommendation cannot be given as to the probable usefulness of the total sulphur‐screening procedure. A strong negative correlation was observed between both methionine and sulpho‐amino acids/16 g of N and % crude protein. Similarly, a negative relationship was observed between total sulphur/16 g of N and % crude protein.

Action of Miracil D and related compounds on histone synthesis and phosphorylation in regenerating liver

The effect of Miracil D and hycanthone on 3H-amino acid incorporation into histones was studied under conditions known to cause a greater than 90% inhibition of thymidine incorporation into DNA of regenerating rat liver. A dose level of 50 mg of either drug per kg body weight administered 8 h after partial hepatectomy caused an approximate 50% inhibition of amino acid incorporation into fl, f2b and combined f2a plus f3 histone in 24-h regenerating liver. There was little or no effect on amino acid nitrogen concentration or incorporation of 3H-amino acid into the acid-soluble fraction, cytoplasmic proteins or acid-insoluble nuclear proteins. Under the same conditions, Miracil D caused a 65% inhibition of 32P incorporation into lysirierich f1 histone whereas a structurally related compound, GE-99, did not have a significant inhibitory effect on this parameter nor on [ 3H]thymidine incorporation into DNA. Temporal studies with hycanthone revealed a suppression of the increased phosphorylation of fl histone in regenerating rat liver without influencing the phosphorylation of other histones. The data support the concept of coordinated control of DNA synthesis and phosphorylation of fl histone.

Effects of formamidoxime on macromolecular synthesis in regenerating liver and hepatomas

Formamidoxime caused an inhibition of [ 3H]thymidine incorporation into DNA in regenerating liver and transplanted hepatomas of different growth rates when administered by i.p. injection to rats. A dose level of formamidoxime (500 mg/kg body weight) which caused at least a 75% inhibition of DNA synthesis in these tissues had little or no effect on the incorporation of [ 3H]orotate into total RNA. After administration of formamidoxime there was no significant effect on amino acid nitrogen concentration in the tissues. The incorporation of 3H-labeled amino acids into acid-soluble material, cytoplasmic proteins and acid-insoluble nuclear proteins were either unaffected or showed only small changes after treatment of rats with the drug. In regenerating rat liver and Morris hepatomas 7787 and 7777, formamidoxime caused an inhibition of incorporation of 3H-labeled amino acids into both lysine-rich and arginine-rich histones. In the host livers of rats bearing the transplanted hepatomas, histone synthesis was less affected. The data indicated that formamidoxime causes inhibitory effects which are similar in nature and extent to those previously shown for the structurally related compound, hydroxyurea, in the regenerating rat liver and demonstrated that these effects can also be observed in liver tumors.

Storage stability of mixed hyperalimentation solutions

Two mixed hyperalimentation solutions (4.25% crystalline amino acid solutions in 25% dextrose and 5% casein hydrolysate in 25% dextrose) were analyzed for chemical stability after storage at room and refrigerated temperatures for 14 days, and the microbial growth supporting potential of various hyperalimentation solutions was assessed. Both of the solutions tested chemically darkened slightly at room temperature, but no significant changes in dextrose, amino acid or total nitrogen content, titratable acidity or pH were noted after two weeks. Of five organisms tested, only Candida albicans underwent appreciable growth in solutions of 5% casein hydrolysate in 25% dextrose (in 24 hours) and in 4.25% crystalline amino acid solution in 25% dextrose (in 48 hours). Although the mixed hyperalimentation solutions tested can probably be left safely at room temperature for 12 hours, they should be refrigerated until used.

The nature of the organic nitrogen of soils

Examination of the 6N HC1 hydrolysates from 14 different proteins indicated that a considerable proportion of the total protein nitrogen in the hydrolysates, as determined by the micro-Kjeldahl method, was not accounted for by the NH4-N and the α amino nitrogen found in the hydrolysates. It seems clear that this hydrolysable unidentified nitrogen (HUN) originates mainly from non-amino nitrogen atoms present in arginine, tryptophan, lysine and proline. These nitrogen atoms do not satisfy the conditions necessary for reaction with ninhydrin. The amounts of each amino acid in a particular protein determine the HUN value which will be obtained for 6N HC1 hydrolysates of that protein. There is good agreement between the HUN values for a wide range of proteins when calculated from the amino acid composition of the protein and when determined experimentally. It is concluded that these findings indicate a considerably higher content of amino acid nitrogen in the organic nitrogen of soils and leaf litter than was previously considered to be the case. It is suggested that the findings support the contention that the organic nitrogen of soils contains leaf protein complexes.

The non-protein nitrogen composition of grass silage:III. The composition of spoilt silages

SUMMARYThe nitrogenous composition of the water soluble, non-protein nitrogen fractions of three samples of high-pH-spoilt silage and one sample of overheated silage were examined in detail. The amino acid nitrogen content of the high-pH-spoilt silages declined with increasing extent of spoilage, due to a selective degradation of the amino acids. Losses of amino acids were associated with proportionate increases in the amount of volatile basic nitrogen. Lower aliphatic amines were not present and it was therefore concluded that the ultimate end product of nitrogen metabolism in high-pH-spoilt silages was ammonia. Only low concentrations of putrefaction products, such as putroscine, cadaverine and histamine were present.The composition of the non-protein nitrogen fraction of the overheated silage was unusual in that the ammonia nitrogen content was high and associated with the complete destruction of certain amino acids. The free amino acid nitrogen content was low but this was partially compensated for by a very high ‘peptide’ nitrogen content. There was no evidence of putrefaction products in this silage.

Amino acid nitrogen and proteins in the haemolymph of adult desert locusts, Schistocerca gregaria

The changes in amino acid nitrogen, proline, and protein content in the haemolymph of adult desert locusts were followed up to 60 days from the time of adult emergence. Large amounts of amino acid nitrogen are present in young insects. The highest concentration was observed on the second day in both sexes and a gradual decline was noticed after 8 days. Proline content in haemolymph followed almost a similar pattern to amino acid nitrogen. Protein levels declined during the first 3 days, increased rapidly up to 15 days, and remained more or less constant thereafter in both sexes. The possible significance of these observations is discussed. A maximum of twelve and ten protein bands was observed in female and male haemolymph samples by polyacrylamide gel electrophoresis. The electrophoretic patterns became more or less similar after a week's time after final ecdysis and consisted of at least ten protein bands in female and eight in male electropherograms. Gel chromatography on Sephadex G-150 column resolved the mixture of haemolymph proteins of male and female locusts 3 to 7 days old into three main fractions. The presence of sex specific, vitellogenic proteins, and human serum albumin-like proteins was detected. By electrogel chromatographic techniques at least 26 haemolymph proteins were found in females and 21 in males. Approximate molecular weights, diffusion constants, and Stoke's radii of all the 47 haemolymph proteins are reported for the first time.