Dietary Amino Acid Requirements Research Articles

The tissue and dietary protein and amino acid requirements of pigs from 8.0 to 20.0 kg live weight

AbstractForty-three entire males were used to determine the pig's tissue requirements for protein and amino acids from 8·0 to 20·0 kg, and provide information on the capacity of diets formulated with conventional ingredients to contain the same levels and balances of amino acids as ideal protein to supply these nutrients. Seven diets with similar digestible energy (15·9 MJ digestible energy (DE) per kg) and crude protein concentrations from 119 to 232 g/kg (8·7 to 17·3 g lysine per kg) were offered ad libitum between 8·0 and 200 kg live weight. The rate of protein deposition was determined by comparative slaughter. The composition of the protein deposited in the whole empty body was determined from amino acid analyses of pigs killed at 8·0 kg and from the two extreme dietary treatments at 20·0 kg. Growth performance and the rates at which protein and lysine were deposited in the empty body increased linearly with increasing dietary protein concentration up to 187 g/kg and remained relatively constant thereafter. The corresponding dietary protein and lysine intakes required to support maximal protein accretion were 178 g/day (11·7 g/MJ DE) and 13·0 g/day (0·84 g/MJ DE) respectively. Based on the maximal deposition rates for protein (91·8 g/day), and lysine (5·96 g/day) and endogenous protein loss (77middot;6 g/day) estimated from the linear component of the relationship determined between protein deposition and apparent digestible protein intake, the pig's tissue requirements for protein and lysine were only 99·4 g/day (6·5 g/MJ DE) and 6·46 g/day (0·43 g/MJ DE) respectively. This disparity between the pig's tissue protein and amino acid requirements and the dietary levels needed to support these was associated with the fact that the apparent digestibility and biological value of the dietary protein were 0·92 and 0·602 respectively. Apart from small differences in the lysine content of body protein and the methionine: lysine ratio, the average amino acid composition of pigs killed at 8·0 kg, and from the diet of highest protein concentration at 20 kg, was similar to that of ideal protein, indicating that the low utilizability of dietary protein for tissue growth and maintenance was probably associated with low amino acid digestibility and/or availability. The implications of the results with respect to expression of the growing pig's requirements for protein and amino acids are discussed.

Whole-body amino acid composition and comparative aspects of amino acid nutrition of the goldfish, golden shiner and fathead minnow

Pond-raised fingerling goldfish ( Carassius auratus), golden shiners ( Notemigonus crysoleucas) and fathead minnows ( Pimephales promelas) were analyzed for whole-body amino acid composition. All three species had similar amino acid patterns in whole-body tissue. These compositional data were also used to compute essential amino acid ratios ( A E ratios) which were compared with the quantified amino acid requirements of another cyprinid species, the common carp ( Cyprinus carpio). The whole-body A E ratios of the three baitfish species were very similar to the A E ratios of the carp requirement values. Since previous studies have established a high correlation between whole-body amino acid patterns and dietary amino acid requirement patterns of several fish species, the whole-body amino acid values determined in this study will provide indices for formulating diets for the goldfish, golden shiner and fathead minnow.

Dietary amino acid balance and requirements for pigs weaned at 3 weeks of age

ABSTRACTNitrogen balance was measured in a series of experiments to determine the optimum balance between lysine, threonine and methionine plus cystine by successive additions of the free amino acids to a basal diet of barley, soya bean meal and tallow. The basal diet had a calculated digestible energy (DE) value of 14·5 MJ/kg and a crude protein content of 146 g/kg. The ranges of total lysine; threonine and methionine plus cystine tested were (g/kg) 6·6 to 11·8, 4·9 to 6·9 and 4·3 to 71, respectively. Latin-square designs were used involving a total of 33 pigs. Nitrogen utilization was optimized in pigs of 3 to 9 weeks of age when each kg of diet contained 10·5 g lysine, 6·4 g threonine and 5·0 g methionine plus cystine, corresponding to a ratio of 100: 61: 48. Thereafter, five diets were formulated in which the same ratio was maintained, but at different protein levels (129 to 192 g/kg). Again the diets were based on barley, soya bean meal and tallow supplemented with free amino acids. These diets were compared, in both nitrogen balance and performance experiments, with a conventional early-weaning diet with a protein content of 240 g/kg. All six diets had the same calculated DE value (14·5 MJ/kg). The N balance experiment was of Latin-square design and involved 18 pigs, and the performance experiment used 36 pigs fed individually from 3 to 9 weeks of age. A diet containing 0·99 g lysine per MJ DE (14·4 g lysine and 192 g balanced protein per kg) was considered to be adequate on the basis of the growth rate and food conversion efficiency results obtained.

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,

Total Aromatic Amino Acid Requirement, Phenylalanine Requirement and Tyrosine Replacement Value for Fingerling Channel Catfish

A series of experiments was conducted to determine the aromatic amino acid requirement, the tyrosine replacement value for phenylalanine and the phenylalanine requirement under conditions of adequate tyrosine for fingerling channel catfish. Effects of excessive dietary levels of tyrosine were also investigated. The studies were conducted utilizing casein and gelatinbased diets supplemented with crystalline L-amino acids to correspond to the pattern of 24% whole egg protein. Based on 8-week growth studies, the total dietary aromatic amino acid requirement for fingerling channel catfish was approximately 1.20 +/- 0.06% (50% of the dietary protein) of which about 50% could be supplied by tyrosine. The phenylalanine requirement per se, based on growth and feed efficiency, was determined to be 0.47 +/- 0.02% and 0.49 +/- 0.02%, respectively. High dietary levels of tyrosine (up to 10%) did not adversely affect performance of fingerling channel catfish. It appears that neither serum-free phenylalanine nor serum-free tyrosine can be used to accurately predict dietary aromatic amino acid adequacy for the fingerling channel catfish.

Effects of dietary protein levels during lactation to first-litter sows fed a fortified corn gestation diet.

Two experiments were each conducted at two locations to determine the efficacy of feeding varying dietary protein levels to first-litter lactating sows that had been fed a fortified corn diet (8.2% C.P.) during gestation. Gilts at both locations were limit fed the corn diet approximately 30 days prebreeding and throughout pregnancy at the rate of 1.82 kg/day. Lactation diets were fed after parturition on a restricted basis the first week postpartum then ad libitum until weaning (28 days). Creep feed was not supplied to the pigs. Lactation diets containing from 12 to 20% protein were formulated by altering the ratio of corn and soybean meal. Litter size was equalized to eight pigs in the first experiment but not in the second. Total protein concentrations in milk and blood serum were determined on days 14 and 28 postpartum of the second experiment. Although there were differences between locations, overall gestation performance was satisfactory. Sow weight loss was greatest and feed intake, litter gain and pig weight at weaning were lowest when the lower protein level was fed. Sow feed intakes and pig gains increased by 14 and 28 days as sow dietary protein levels increased. The number of pigs weaned per litter was not affected by lactation protein level (Experiment II). Milk protein concentrations on days 14 and 28 were somewhat indicative of pig performance but was not significantly correlated. These results suggest that sows fed a corn gestation diet may have a higher dietary amino acid requirement during lactation than sows fed higher gestation protein levels.

DIET AND FEEDING INTERVAL EFFECTS ON SERUM AMINO ACID CONCENTRATIONS OF GROWING SWINE

Four experiments were undertaken to establish the effects of diet and feeding regimen on serum amino acid concentrations of growing swine. Single meal feeding resulted in fluctuations in serum amino acid levels that could not be attributed solely to diet. A short-interval feeding regimen was proposed that resulted in relatively stable serum amino acid concentrations during the refeeding program. This procedure was suggested to be useful in attempting to evaluate protein quality by examination of serum amino acid fluctuations. A semipurified diet was observed to result in extremely high serum levels of methionine and several other amino acids, raising the possibility that the dietary amino acid requirements of swine fed semipurified diets were lower than accepted values. When the dietary methionine concentration was altered from 0.41% to 0.70%, an adaptation period of about 3 days was required to stabilize serum methionine at a new level.

Influence of Amino Acid Level in the Diet upon Amino Acid Oxidation by the Rat

A series of experiments was conducted to develop and evaluate a nondestructive method for estimating the amino acid requirements of the growing rat. Rats fed graded levels of lysine were injected with radioactively labeled lysine via heart puncture. The production of radioactive carbon dioxide was used as an index of the amount of lysine oxidized. Results obtained indicated that the oxidation of lysine did not increase markedly until the dietary lysine intake was increased above that level at which average daily gain and gain/feed were maximal. This level was approximately 115 mg lysine consumed per day for a 200-g rat fed ad libitum. The adaptation of the oxidative mechanisms in the rat to changes in the dietary amino acid intake was shown to be relatively rapid. The lysine requirement expressed in terms of daily lysine consumption did not appear to change with time for a period of up to 28 days. The oxidation of a second amino acid, methionine, by rats fed graded levels of lysine was shown to be independent of lysine intake. It was concluded that the oxidation technique provides a means for estimating the dietary amino acid requirement for a specific growth rate in the growing rat.

Dietary Amino Acid Requirements of the Aphid Myzus persicae Affected by Antibiotic Uptake

Plant-reared, apterous adult Myzus persicae were allowed to feed on synthetic diets with and without 0.01% aureomycin, and their progenies raised on antibiotic-free diets from which single amino acids were omitted. The individual omission of all 10 “essential” amino acids from diets fed to larvae derived from the antibiotic-treated mothers resulted in a considerable reduction in larval growth. Larvae derived from mothers fed an antibiotic-free diet exhibited such a reduction only when fed histidine-, isoleucine-, or methionine-free diets. In contrast, the individual omission of the “nonessential” amino acids did not affect the growth of larvae whether they were derived from mothers fed antibiotic-free diet or from mothers fed the diet containing aureomycin. The results suggest that the symbiotes of M. persicae supply the aphid with most of the essential amino acids in amounts sufficient for growth, when these nutrients are inadequately or not available to the aphids in their food. No improvement in the growth of larvae from antibiotic-treated mothers was obtained by incorporating lipid extracts of aphids or cholesterol into “complete” diets, in attempts to supply the aphids with dietary sterol.

Dietary amino requirements for Heliothis zea determined by dietary deletion and radiometric techniques

Feeding tests using a diet containing 18 allo free, l-amino acids as the major source of nitrogen showed that valine, leucine, lysine, arginine, histidine, isoleucine, threonine, tryptophan, phenylalanine, and methionine were indispensable for larval growth. Although larval growth rates, pupal weights, and survival to the pupal and adult stages on the amino acid diet were comparable to those obtained on a casein-wheat germ diet, most adults reared on the amino acid diet showed wing and/or body deformities. To verify further the larval dietary amino acid requirements, amino acid synthesis from glucose-U- 14C was investigated. Fourth instar larvae were reared on a synthetic diet containing glucose-U- 14C and the specific activities of the individual amino acids isolated from the whole carcass and from the protein extracted from the carcass were determined. The results of the radiometric study agreed with those obtained from feeding tests in that the radioactive carbon incorporated into the carbon chain of valine, leucine, lysine, arginine, histidine, isoleucine, threonine, and methionine showed sufficiently low 14C activity that they could be classified as indispensable nutrients. The relatively high labelling in aspartic acid, glutamic acid, glycine, serine, alanine, and cysteine indicated that the insect is capable of synthesizing these amino acids from glucose. Results of the radiometric study were inconclusive regarding the dietary need for phenylalanine, tyrosine, and tryptophan: however, feeding studies showed the phenylalanine and tryptophan were indispensable and tyrosine was dispensable. Proline was shown to be dispensable by the deletion technique, and the relatively low 14C labelling in proline was accounted for by dilution of the 14C with unlabelled components of the diet during the indirect synthetic route from glucose to proline rather than by limited synthesis of proline from glucose.

Nutritional Evidence for the Absence of the Complete Ornithine-Urea Cycle in the Insect, Argyrotaenia velutinana (Lepidoptera: Tortricidae)

Studies were made of the ornithine-urea cycle in the plant-feeding insect, Argyrotaenia velutinana (Walker), by replacing dietary arginine with intermediaries involved in the cycle. Axenic rearing on graded concentrations of arginine showed that arginine is a dietary requirement. This was in agreement with previous studies using the radioactive tracer technique which demonstrated that arginine was not synthesized by the insect. Likewise, the optimum dietary concentration of arginine found in this study was between 0.10 and 0.15% at a 2.0% dietary amino acid mixture level, which agreed with previous studies of the dietary quantitative amino acid requirements based on the pattern of amino acids found in the carcass of the insect. The dietary arginine requirement could be satisfied by substituting twice the equimolecular amount of citrulline: ornithine, creatine, or guanidoacetic acid could not replace arginine. Biological studies resulting from axenic rearing for three successive generations on a diet in which citrulline replaced arginine indicated that the conversion of citrulline to arginine was nutritionally adequate to satisfy the requirements for growth, development and reproduction of the insect.

Amino Acid Synthesis from Glucose-U-14C in Argyrotaenia velutinana (Lepidoptera: Tortricidae) Larvae

In previous studies using the dietary amino acid deletion technique, it was found that the insect Argyrotaenia velutinana (Walker) required the same 10 amino acids indispensable for the rat. To further verify the dietary amino acid requirements of this insect, amino acid synthesis from glucose-U-14C was investigated in the larval stage. For this, fifth-instar larvae were reared aseptically on a synthetic medium containing glucose-U-14C. The relatively high specific activity measurements for aspartic acid, glutamic acid, glycine, serine, alanine and cysteine indicate that the insect is capable of synthesizing these amino acids from glucose. Lysine, histidine, arginine, valine, methionine, isoleucine, leucine, phenylalanine and threonine showed low specific activity measurements; therefore, these amino acids are classified as nutritionally indispensable. These results agree with those obtained by the amino acid deletion technique. Although tyrosine showed no radioactivity it may be considered a dispensable amino acid because it was shown to be dispensable by the deletion technique, and its synthesis from phenylalanine has been demonstrated in other insects. Proline was shown to be dispensable by the deletion technique and the low specific activity measurement obtained for proline in this study was accounted for by dilution of the 14C with unlabeled components of the diet during the indirect synthetic route from glucose to proline.

Some Problems in Dietary Amino Acid Requirements

Some Problems in Dietary Amino Acid Requirements

The amino acid composition of broiler cockerels in relation to their dietary amino acid requirement

(1963). The amino acid composition of broiler cockerels in relation to their dietary amino acid requirement. British Poultry Science: Vol. 4, No. 3, pp. 285-290.

Influence of Age and Dietary Protein on Certain Free Amino Acids in Chick Blood Plasma

DURING the past few years, there has been a great deal of interest in studying the relationship of dietary amino acid levels to the concentrations of free amino acids in the blood plasma. Richardson et al. (1953) demonstrated that the concentrations of the free amino acids in chick plasma were related to the level of the same amino acids in the diet. In an experiment conducted to determine the rate and extent of absorption of amino acids from the intestinal tract of dogs, Denton and Elvehjem (1954) reported that the concentrations of amino acids in the blood corresponded roughly to the amino acid composition of the protein fed. Recently, Tonkinson et al. (1961) have presented data suggesting a correlation of the free amino acids in the blood plasma with the dietary amino acid requirements for turkeys.Since the blood serves as the primary means of transport of constituents to the …

Studies on a Short-Term Procedure for Determining Amino Acid Requirements of Laying Hens

MACHLIN (1954) reported that a reduction of dietary protein or tryptophan eleven days after administration of methionine-S35 to laying hens resulted in a relative increase in sulfur35 deposition in the egg albumen. This increase in deposition of sulfur35 due to an amino acid deficiency suggested a possible procedure for estimating dietary amino acid requirements of the laying hen. Fisher and Johnson (1956) reported the development of a synthetic diet containing free amino acids instead of protein that maintained egg production for a 30-day experimental period. Since the cost of conducting research with synthetic diets of this type limits the duration of the experimental periods, an assay procedure whereby amino acid deficiencies could be detected in a short period of time would be valuable for determining dietary amino acid requirements.The following studies using a lysine deficient laying diet were designed to ascertain if the results obtained by the procedure described …

Dietary Bulk and Amino Acid Requirements

Dietary Bulk and Amino Acid Requirements

The Amino Acids Required for the Complete Replacement of Endogenous Losses in the Adult Rat: One Figure

For the replacement of endogenous losses of nitrogen, the adult rat not need the following dietary amino acids : lysine, leucine, histidine, arginine, and phenylalanine. These amino acids are all required for growth in the rat.The adult rat requires both cystine and methionine for the maintenance of nitrogen equilibrium. The cystine requirement can be covered by dietary methionine, but methionine requirement cannot be satisfied by dietary cystine.The endogenous metabolism of the adult rat involves the destruction of tyrosine, or of tissue constituents derived from tyrosine, but not the destruction of phenylalanine. The losses thus incurred me be replaced by iether dietary tyrosine or by dietary phenylalanine.The differences between the dietary requirements of amino acids for growth and for maintenance of nitrogen equilibrium may be satisfactorily explained on the basis of differences between rates of supply and of demand with respect two functions.The adult rat may be maintained in nitrogen equilibrium on a nitrogen supply containing only the following amino acids : threonine, isoleucine, tryptophane, valine, methionine, tyrosine and norleucine.The precise function of norleucine in maintaining the nitrogenous integrity of the tissues needs further study. It may function in promoting the synthesis of lysine or of leucine, or of both.