[Plasma tryptophan in a protein controlled diet in depressed patients]

Cerebral serotonin is synthetized from its blood precursor: tryptophan (TRP), an essential amino acid (6). TRP has been extensively studied since serotonine has been reported to be involved in the pathogenesis of depression (9). In one hand, brain serotonin content depends on regulation by plasma large neutral amino acids (LNAA): leucine, isoleucine, valine, tyrosine and phenylalanine that compete with TRP to cross over the blood brain barrier (7, 13). In the other hand TRP is largely linked with albumin. So, we have studied plasma total TRP, free TRP and the ratio TRP on LNAA as potential cerebral serotonin index. The aim of this study is to observe the blood variations of the biological parameters in fasting and postprandial conditions in 8 depressed women, aged from 57 to 78 years, on a short protein controlled diet: 4 women had TRP poor then rich diet and the others 4 rich then poor. Alimentary proteins modulated diets and each patient was his own control: the results under modulated diet were compared with those under normal diet at the same time. More over, 2 psychotic patients aged 58 and 70 years have been studied at the same time, in each group. Biological datas were compared with clinical evolution.

Tryptophan depletion in patients with obsessive-compulsive disorder who respond to serotonin reuptake inhibitors

METHODS

The effects of short-term tryptophan depletion were examined in 15 patients with DSM-III-R obsessive-compulsive disorder who had demonstrated symptom reduction following treatment with serotonin reuptake inhibitors. Patients received a 24-hour, low-tryptophan (160-mg/d) diet followed the next morning by a drink of 15 amino acids. A double-blind, placebo-controlled cross-over design was used.

RESULTS

The diet and the amino acid drink reduced free plasma tryptophan levels by a mean of 84% 5 hours later. Short-term tryptophan depletion did not significantly change mean ratings of obsessions and compulsions. In contrast, mean depression ratings were significantly increased with tryptophan depletion compared with the control (tryptophan-supplemented) testing.

CONCLUSION

Maintenance of serotonin reuptake inhibitor-induced improvement of obsessive and compulsive symptoms, unlike remission of depressive symptoms, may not depend on ongoing short-term availability of serotonin.

Effects of inhibition of serotonin synthesis on 5-hydroxyindoleacetic acid excretion, in healthy subjects

The urinary excretion of 5-hydroxyindoleacetic acid (5-HIAA), the main metabolite of serotonin, reflects the content and turnover of gastrointestinal (GI) serotonin. Employing longitudinal measurements of 5-HIAA, the authors investigated in healthy subjects (n = 43) how manipulations of serotonin synthesis affect GI serotonin. Under conditions of serotonin-free diets, the intersubject and intrasubject variability (coefficient of variation) for 5-HIAA excretion averaged 33% and 14%, respectively. Dietary tryptophan restrictions to 50% of minimal daily requirements (which is equivalent to a 10-fold reduction in baseline tryptophan intake) decreased by half the urinary excretion of 5-HIAA, irrespective of the caloric content of diet. Restoration to the regular tryptophan intake produced a rapid normalization of the 5-HIAA excretion. Neutral amino acids are known to compete with the intestinal transport absorption mechanisms of tryptophan. Administration of neutral amino acids (1.8 g, by mouth, three times a day, before each meal) or of carbidopa (50 mg, by mouth, three times a day for 3 days) to a normal tryptophan diet failed to alter significantly the 5-HIAA excretion. Further, neutral amino acids failed to enhance the reduction in 5-HIAA produced by the low-tryptophan diet. The failure of these treatments to reduce 5-HIAA excretion could be due to large capacity transport and decarboxylation systems for tryptophan. Other possibilities are discussed. In summary, dietary tryptophan is essential for the maintenance of GI serotonin. Reductions or increases in dietary tryptophan are the easiest and most effective method to alter GI serotonin.(ABSTRACT TRUNCATED AT 250 WORDS)

Intragastric tryptophan reduces glycemia after glucose, possibly via glucose-mediated insulinotropic polypeptide, in early-weaned piglets

The aim of this experiment was to investigate the influence of oral tryptophan on insulin, glucose-mediated insulinotropic polypeptide and glucose concentrations in early-weaned piglets. Piglets were given by intragastric infusion, at the same level of feeding, either a tryptophan-deficient or tryptophan-adequate diet for 22 d. During the experiment blood samples were taken after intragastric infusion of 1) the accustomed meal, 2) a glucose plus tryptophan load and 3) a glucose load. Plasma samples were analyzed for insulin, glucose-mediated insulinotropic polypeptide, glucose and lactate. After the accustomed meal plasma insulin concentrations were augmented and liquid gastric emptying faster in pigs fed tryptophan-adequate compared with tryptophan-deficient diets (P < 0.05) but glucose-mediated insulinotropic polypeptide, glucose and lactate were unaffected. The addition of tryptophan to a glucose load increased glucose-mediated insulinotropic polypeptide and reduced glucose in both tryptophan-adequate and tryptophan-deficient diet fed pigs (P < 0.05). Piglets adapted to the tryptophan-adequate diet had a greater glucose-mediated insulinotropic polypeptide response to intragastric glucose plus tryptophan than piglets adapted to the tryptophan-deficient diet. Adaptation to a tryptophan-adequate diet seems to increase the release of glucose-mediated insulinotropic polypeptide due to infusion of a tryptophan-adequate compared with a tryptophan-deficient diet. The addition of tryptophan to a glucose load reduces the level of glycemia, possibly through glucose-mediated insulinotropic polypeptide-mediated glucose disposal.

Nutrition support for glutaric acidemia type I

Glutaric acidemia type I is a rare, autosomal recessive, inborn error of lysine and tryptophan metabolism. This disorder is caused by a defect in the mitochondrial enzyme glutaryl-coenzyme A dehydrogenase, resulting in permanent or episodic elevations of glutaric acid. Despite clinical variability, untreated children often experience progressive neurologic damage that frequently leads to death. Recent evidence suggests that a lysine- and tryptophan-restricted diet and pharmacologic therapy with oral riboflavin and L-carnitine may arrest the neurologic deterioration. Several cases of normal growth and development have been reported in children diagnosed and treated before neurologic insult. In this article, we review previously published experience with dietary and pharmacologic therapy and provide guidelines for nutrition support based on our experience of treating four affected children. We suggest that dietary restriction of lysine and tryptophan is a safe and potentially effective therapy for individuals with glutaric acidemia type I.

Effect of 6R-L-erythro-5,6,7,8-tetrahydrobiopterin on the extracellular levels of dopamine and serotonin in the rat striatum: a microdialysis study with tyrosine or tryptophan infusion

The present study demonstrates the effects of 6R-L-erythro-5,6,7,8-tetrahydrobiopterin (6R-BH4) on turnover of dopamine and serotonin (5-HT) in rat striatum during continuous infusion of the amino acids tyrosine and tryptophan. By monitoring with microdialysis, it was found that the increase in dopamine and homovanillic acid (HVA) concentrations in rat striatal extracellular fluid (ECF) induced by 6R-BH4 was further enhanced by the continuous infusion of tyrosine at a relatively low dose (1 mumol/min/kg) as compared with the concentration which saturates tyrosine hydroxylation. This dose of tyrosine alone did not induce the elevation of dopamine and HVA concentrations in ECF. In contrast, though the concentration of 5-HT and 5-HIAA in striatal ECF was gradually increased by tryptophan infusion, 6R-BH4 had no further effect. Although the higher output of dopamine into ECF was induced by the dialytic perfusion of 6R-BH4 via the microdialysis probe into striatum, tyrosine infusion had no further effect on dopamine concentration in the dialysates. The in vivo measurement of DOPA accumulation during NSD 1015 perfusion suggests that the enhancement of dopamine concentration in ECF induced by tyrosine infusion and 6R-BH4 might be attributable to an increase in tyrosine hydroxylase activity in striatum. Tryptophan hydroxylase was also activated by tryptophan infusion and/or 6R-BH4, however, it did not induce an increase in 5-HT concentration in striatal ECF.

[Body niacin status in experimental diabetes mellitus; effect of protein level in the ration]

Administration of a high-protein diet providing 7-7.8 g of tryptophan per kg of the ration to rats with streptozotocin and alloxan diabetes mellitus resulted in development of a trend to increased liver content of nicotinamide coenzymes and in increased 1-methylnicotinamide excretion with the urine in both groups of animals, this reflecting increased niacin synthesis from tryptophan. Sugar-reducing effect of high-dose nicotinamide was not potentiated by increase of protein share in the ration. These results permitted the authors to suggest that intensification of endogenous niacin synthesis from tryptophan contained in the ration may be one of the mechanisms of a protective effect of high-protein diets in diabetes.

Quantitative efficacy of niacin sources for chicks: nicotinic acid, nicotinamide, NAD and tryptophan

A niacin-deficient diet based upon corn and casein was used to establish growth-promoting efficacy of various sources of niacin activity. In the presence of excess dietary nicotinamide, chicks fed the corn-casein diet achieved maximal weight gain when 100 mg/kg of L-tryptophan was supplemented. The basal diet for efficacy studies therefore contained 100 mg/kg of added tryptophan and no supplemental nicotinic acid. Weight gain in the linear response surface of the growth curve proved to be a far better measure of niacin bioactivity than tissue accumulation of NAD(P). Slope-ratio growth efficacy studies indicated that excess dietary tryptophan was 1.94 +/- 0.14% as efficient as nicotinic acid in furnishing bioavailable niacin activity (52:1, wt:wt). Relative to nicotinic acid used as a standard (100%), nicotinamide bioactivity was 124%. Nicotinamide in NAD was utilized with an efficiency of 95% relative to nicotinamide per se.

Protein and energy relationships in the broiler chicken. Effects of protein quantity and quality on metabolism

Male broiler chickens growing from 7 to 35 d were fed on a diet containing 150 g crude protein (N x 6.25)/kg diet supplemented with lysine to equal that in diets containing 166, 183 and 200 g crude protein/kg diet (Expt 1). A second group of male broiler chickens growing over the same period were fed on a diet containing 120 g crude protein/kg supplemented with lysine, arginine, tryptophan, threonine and isoleucine equal to that in diets containing 144, 172 and 200 g crude protein/kg diet (Expt 2). Growth was improved by lysine supplementation but not to the level attained by feeding 200 g crude protein/kg (Expt 1). Lysine, arginine, tryptophan, threonine and isoleucine supplementation of a low-protein diet also improved growth, but growth again fell short of that attained by feeding a diet containing 200 g crude protein/kg. Plasma insulin-like growth factor-1 and thyroxine concentrations increased and triiodothyronine decreased as the crude protein level increased from 150 to 200 g/kg diet. Supplemental lysine did not affect plasma levels of these hormones. Although dietary crude protein levels noticeably changed rates of in vitro lipogenesis, changing either the level of a single limiting amino acid or the levels of several limiting amino acids did not change lipogenesis.

Huntington's disease and low tryptophan diet

Beal et al have postulated that abnormal metabolism of tryptophan or quinolinic acid underlies the mechanism which causes brain damage in Huntington's disease. A case history is reported where a low tryptophan diet was associated with an unexpectedly good outcome. It is possible that a low tryptophan diet may alter the course of Huntington's disease, either by postponing onset or diminishing the severity of symptoms.

Regulation of hypothalamic preprogrowth hormone-releasing factor messenger ribonucleic acid expression in food-deprived rats: a role for histaminergic neurotransmission

To determine the component(s) of dietary protein that regulates GH-releasing factor (GRF) synthesis, we measured hypothalamic prepro-GRF mRNA by solution hybridization/nuclease protection analysis in food-deprived rats refed protein-free diets (PF) supplemented with individual amino acids. Adult male Sprague-Dawley rats were allowed free access to food (Fed), food deprived for 72 h (FD), or FD then refed for 72 h with a normal (NF) diet, a protein-free (PF) diet, or PF diets containing tyrosine, tryptophan (Trp), glutamic acid, or histidine (His). Food-deprived rats displayed the expected 80% reduction in hypothalamic prepro-GRF mRNA. Upon refeeding, levels were normalized in rats refed a normal diet, but not in those refed a PF diet alone or with tyrosine, Trp, or glutamic acid. In contrast, prepro-GRF mRNA was restored to 70% of Fed values by a PF diet with His. Supplementing a PF diet with His was sufficient to maintain hypothalamic prepro-GRF mRNA expression, as 3 days of feeding replete rats with PF diet or PF diet with added Trp resulted in a 50% reduction in prepro-GRF mRNA, whereas levels were reduced 25% by feeding animals a PF diet with His. Groups of rats allowed free access to food were treated for 72 h with two daily injections of 100 mg/kg alpha-fluoremethylhistidine, a specific irreversible inhibitor of histidine decarboxylase, to determine if the effect of His on prepro-GRF mRNA depended on neural conversion to histamine. alpha-Fluoremethylhistidine-treated rats showed a 40% reduction in hypothalamic prepro-GRF mRNA, with no concomitant change in preproneuropeptide-Y or preprosomatostatin. These data indicate that decreased hypothalamic prepro-GRF mRNA in FD rats is due in part to the lack of dietary and provide clear evidence for a role of the histaminergic neural system in the regulation of hypothalamic GRF expression.

Supplemental dietary L-tryptophan effects on growth, meat quality, and brain catecholamine and indoleamine concentrations in turkeys

1. An experiment was conducted to investigate the effects of feeding supplemental tryptophan during the two weeks before market on growth, mortality during transportation, meal quality and brain neurotransmitter concentrations in male turkeys. 2. Brain serotonin, 5-hydroxyindoleacetic acid and norepinephrine concentrations were increased dose-dependently with 1.0, 2.0 and 3.0 g/kg supplemental dietary tryptophan. 3. Supplemental dietary tryptophan had no effect on body weight gain, food intake, food efficiency or mortality. 4. Carcase and individual thigh weights were significantly heavier in those birds fed 1.0 g/kg supplemental tryptophan.

Poly(ADP-ribose) polymerase activity and DNA strand breaks are affected in tissues of niacin-deficient rats

The niacin cofactor, NAD, is the substrate for poly(ADP-ribose) polymerase, an enzyme associated with DNA repair. We investigated, therefore, whether hepatic poly(ADP-ribose) polymerase activity was altered and DNA strand breaks in lymphocytes and liver were greater in niacin-deficient rats. A niacin deficiency was established in weanling rats with diets containing 1.5 mg/kg of niacin. Based on lower growth rates and NAD concentrations in blood, liver and skeletal muscle, this diet maintained rats in a deficient state for 1 mo, and, when the dietary niacin was reduced to 0.5 mg/kg, rats remained deficient for an additional month. The hepatic poly(ADP-ribose) polymerase activity was decreased in one experiment when mean hepatic NAD concentrations were 0.60 and 0.51 mumol/g at d 34 and d 60, respectively, compared with 0.77 and 0.80 mumol/g in pair-fed controls. Enzyme activity, however, was greater than in controls when hepatic NAD concentrations were < 0.30 mumol/g. Strand breaks in DNA did not accumulate except after tissues were exposed to hypoxanthine-xanthine oxidase, a free radical-generating system. Exposure to this system caused more DNA strand breaks in lymphocytes and hepatic nuclei from niacin-deficient rats compared with the same tissues from controls. The results suggest that, in rats, although hepatic poly(ADP-ribose) polymerase activity can be elevated, a severe niacin deficiency may increase the susceptibility of DNA to oxidative damage, likely due to a lower availability of NAD.

Effects of indirectly acting 5-HT receptor agonists on circulating melatonin levels in rats

Because circulating melatonin levels are generally thought to be under the strict control of pineal N-acetyltransferase, little attention has been paid to the impact of an altered availability of serotonin (5-HT) on melatonin formation. In order to see whether melatonin synthesis is stimulated by an increased availability of free, cytosolic 5-HT, we studied the effects of 5-HT precursors, 5-HT releasers and reuptake inhibitors and of monoamine oxidase inhibitors, alone and in combination, on circulating melatonin levels in experimental animals. The administration of tryptophan and 5-HT-releasing drugs (fenfluramine, +/- 3,4-methylenedioxymethamphetamine) to rats caused a dose- and time-dependent elevation of circulating melatonin levels during the day and night. This increase in melatonin was further enhanced by inhibition of monoamine oxidase. The elevation of plasma melatonin caused by 5-HT-releasing drugs was prevented by prior administration of fluoxetine. Monoamine oxidase inhibitors and fluoxetine alone had no effect on circulating melatonin levels. These findings indicate that the administration of indirectly acting 5-HT receptor agonists which increase the free cytoplasmic pool of 5-HT may also elevate circulating melatonin levels. The results of this study suggest that the rate of pineal melatonin synthesis is dependent on the free cytoplasmic pool of 5-HT in pinealocytes and that the drug-induced elevation of this pool stimulates melatonin formation and increases circulating melatonin levels. At least some of the effects of indirectly acting 5-HT receptor agonists, e.g. on sleep, mood, food intake, pain perception, and neuroendocrine secretion, may therefore be mediated by the elevation of circulating melatonin and the subsequent activation of central melatonin receptors.

Behavioral responses of broiler chickens to handling: effects of dietary tryptophan and two lighting regimens

In three 2 x 2 factorial experiments, effects of added dietary Trp (0 or .2%, Experiments 1 and 2; 0 or .4%, Experiment 3) and two lighting regimens [1) constant 23-h photoperiod (23H); or 2) increasing photoperiod (INC)] on behavioral responses of broilers to handling were assessed. In Week 6 of Experiment 1, and Weeks 3 and 6 of Experiments 2 and 3, 32 chickens from each treatment were picked up and held by both legs for 30 s, carried for 60 s, and induced into tonic immobility (TI). In all experiments, chickens reared under INC were more likely to flap when carried, and flapped longer, than chickens reared under 23H (P < .01). In Experiments 2 and 3, INC chickens were more likely to curl the body ventrally when handled and were more susceptible to TI induction than 23H chickens (P < .05). The duration of TI was shorter on INC than 23H in Experiment 2 (P < .05), and longer in Experiment 3 (P < .001). Dietary Trp supplementation resulted in a lower flapping duration and higher incidence of body curling in Experiment 2 (P < .05), and a shorter TI duration in Experiment 3 (P < .05). Flapping, body curling, and TI responses of chickens varied between handlers (P < .05). Vocalization and flapping rates were lower, and flapping incidence and duration of flapping and TI higher, in Week 6 than in Week 3 (P < .05). Chickens reared under INC may be at greater risk of injury during preslaughter handling than chickens reared under 23H.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in serotonin metabolism may elicit obstructive apnoea in the newborn rat

1. Experiments were performed on anaesthetized newborn rats (aged 3-10 days) to know whether an increase in central serotonin levels might favour the occurrence of obstructive apnoeas as previously suggested by in vitro results from our group. 2. The levels of serotonin (5-HT), its precursor 5-hydroxytryptophan (5-HTP) and its metabolite, 5-hydroxyindole-acetic acid (5-HIAA), were analysed in cerebrospinal fluid samples collected at the level of the obex prior to and after intraperitoneal injection of L-tryptophan (50 mg kg-1) in sixty-eight anaesthetized newborn rats (control rats prior to injection and injected rats 15, 30 and 45 min after the injection). A significant increase in 5-HT and 5-HTP levels occurred 30 min after the injection, attesting to the activation of 5-HT biosynthesis. 3. The EMG activity of both the genioglossus and the diaphragm was recorded before and after L-tryptophan load (50 mg kg-1) in twenty-two newborn rats. After the injection of L-tryptophan, the amplitude of the integrated genioglossus activity decreased, or was even abolished, either during a few respiratory cycles or for long periods in twenty-one out of twenty-two animals. Recovery of the genioglossus activity occurred within 45-60 min. 4. The thoracic respiratory movements and the resulting upper airway pressure changes were recorded before and after L-tryptophan injection (50 mg kg-1) in sixty-two animals. In some litters (n = 7), most of the animals (21/25) displayed, within 20-40 min of the injection, recurrent episodes of obstructive apnoea often followed by central ones. These respiratory difficulties became severe and drastic, and led in two instances to respiratory distress and death. Lower doses of L-tryptophan (10 mg kg-1) did not induce any respiratory disorders unless these were potentiated by pargyline treatment (50 mg kg-1, n = 7). The obstructive apnoeas liable to occur after an L-tryptophan load (50 mg kg-1) were prevented by blocking the 5-HT receptor with methysergide (50 mg kg-1, n = 5) or by blocking the 5-HT biosynthesis by applying p-chlorophenylalanine (PCPA) pretreatment at birth (300 mg kg-1, n = 7). In other litters (n = 6), none of the eighteen newborn rats tested were affected by L-tryptophan, however, In five young adult rats, L-tryptophan again had no effect.4+ ĕ

Rat liver is not damaged by high dose tryptophan treatment

Adult male Sprague-Dawley rats were treated with USP-grade L-tryptophan at a level of 250 mg/kg seven times over 14 d or three times over 3 d by gastric gavage. At autopsy liver specimens were prepared for histological study by stains specific for lipids, for glycoprotein and glycogen, and for fine structure by electron microscopy. Liver lipid did not accumulate as a result of tryptophan treatment. In a series of unfed animals, however, liver lipid had accumulated within 24 h of food withdrawal. Tryptophan has been implicated in fatty liver development by several reports that cite each other, but, in all cases but one, unfed animals were used, and the data show that liver lipid was already present in the unfed animals at the beginning of the experiment. Tryptophan has also been cited as causing abnormal liver morphology, but our evidence suggests that such observations are the result of artifact induced by frozen section preparation and not the result of tryptophan treatment. Our experiments indicate that tryptophan administered to rats at dosages in excess of those recommended for humans does not induce fatty liver or other morphological changes detectable by the methods described.

Effect of supplemental niacin on sow reproduction and sow and litter performance

In this study the effects of supplemental crystalline niacin on sow reproduction and sow and litter performance were evaluated using 240 litters produced by 67 sows. A basal 12.80% CP corn-soybean meal-oat diet was supplemented with 0 or 33 mg of crystalline niacin/kg during gestation and lactation. The sows were grouped to equalize initial BW and parity among the two treatment groups. Each sow was fed 2.0 kg/d during gestation and 1.8 kg plus .45 kg per nursing pig during lactation. Sows not culled due to reproductive or structural problems remained on the experiment for five parities (average 3.6). Supplemental niacin did not improve (P > .20) any of the sow reproductive or sow and litter performance variables evaluated, including the subjective scores for sow lameness, toe cracks, and hair and skin condition. In conclusion, these results suggest that a 12.80% CP corn-soybean meal-oat diet provides adequate niacin during gestation and lactation without supplementation with crystalline niacin.

Bioavailable level and source of cysteine determine protein quality of a commercial enteral product: adequacy of tryptophan but deficiency of cysteine for rats fed an enteral product prepared fresh or stored beyond shelf life

Young rats were used in bioassays designed to assess the protein quality and tryptophan as well as cystine adequacy of the enteral product TwoCal-HN that was either freshly prepared or had been stored (nonrefrigerated) in a warehouse for 10 mo (i.e., beyond shelf life). Based upon supplementation studies, cystine was observed to be the first-limiting amino acid in both fresh and expired TwoCal-HN, and tryptophan was not second limiting. Protein efficiency ratio (PER) of expired, but not fresh, TwoCal-HN was lower than that of the casein control diet, but with cystine supplementation, PER of the TwoCal-HN products was equal to or greater than the PER of the casein control. With a diet containing 10 g protein/100 g that also contained energy-furnishing ingredients simulating TwoCal-HN, maximal growth enhancement occurred with a supplement of 1 g cystine/kg diet. Both glutathione and N-acetyl-L-cysteine were observed to be equivalent to an isomolar level of L-cystine in stimulating growth. Using a chemically defined amino acid diet that was singly deficient in tryptophan, bioavailability of tryptophan was determined for casein, fresh TwoCal-HN, expired TwoCal-HN and D-tryptophan. Slope-ratio bioefficacy values relative to L-tryptophan (weight gain regressed on supplemental tryptophan intake) indicated that none of the experimental sources of tryptophan had bioavailabilities different from 100%. The results indicated that tryptophan did not deteriorate, as measured analytically or biologically, as a result of storing TwoCal-HN beyond shelf life.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino acid supplementation of low-protein sorghum-soybean meal diets for 20- to 50-kilogram swine

Five growth experiments (28 or 35 d in duration) with growing pigs (24 kg initially) were conducted to assess the value of added threonine, tryptophan, methionine, and isoleucine in low-protein, lysine-fortified, sorghum-soybean meal diets. Basal 12, 13, and 14% CP diets were fortified with lysine.HCl to contain .62% digestible lysine, the lysine content of the 16% CP control diet included in all experiments. The additions of .12% threonine (.54 vs .42% dietary threonine) to the 12% CP diet in Exp. 1 improved (P < .01) ADG and gain/feed, but additions of .05% tryptophan or .10% methionine were without effect. Interactions of threonine, methionine, and tryptophan additions were nonsignificant (P > .30). Increasing lysine from .71 to .86% or increasing threonine from .54 to .65% in 12% CP diets of Exp. 2 improved (P < .07) gain/feed but did not affect ADG. Neither the addition of .05% isoleucine nor the addition .46% NaHCO3 to the 12% CP diet in Exp. 3 affected performance. All 12% CP diets in Exp. 1 to 3 resulted in performance below that obtained on the 16% CP diet. Addition of threonine to 13% CP (.47 vs .55% threonine, Exp. 4) or 14% CP (.51 vs .58% threonine, Exp. 5) diets tended (P < .12) to improve gain/feed but did not affect ADG. Performance on the 14% CP diet with added threonine and on the 16% CP diet was equivalent. These data suggest a minimum of 14% CP is needed in lysine-threonine fortified, sorghum-soybean meal diets of growing pigs for maximum performance.

Fatal eosinophilia myalgia syndrome in a marrow transplant patient attributed to total parenteral nutrition with a solution containing tryptophan

A 16-year-old white male with acute biphenotypic leukemia developed evidence of the eosinophilia myalgia syndrome associated with total parenteral nutritional support with solutions containing tryptophan, which were given during his initial induction chemotherapy and also after autologous marrow transplantation. He developed pronounced eosinophilia and a vasculitic skin rash, myalgias of the abdomen, upper trunk, and neck, and died of respiratory distress with no evidence of an infectious etiology. Autopsy revealed diffuse vasculitis involving the heart, lungs, kidneys, testes, spleen, liver, skin, gut wall and marrow with neuritis of gut wall nerves and ganglia. Thus, the eosinophilia myalgia syndrome can be associated with parenteral tryptophan administration.

Amino acid supplementation of low-protein sorghum-soybean meal diets for 5- to 20-kilogram swine

Four growth experiments were conducted to determine the value of added threonine (Thr), methionine (Met), tryptophan (Trp), and isoleucine (Ile) in low-protein, lysine (Lys)-fortified, sorghum-soybean meal diets for starting pigs weaned at 28 d. Trials lasted 28 d and average initial weight was approximately 6.5 kg. A 21% CP (1.15% total and .95% digestible Lys) diet was included in all trials. Basal 15, 17, and 19% CP diets were formulated to contain .95% digestible Lys by adding .38, .26, and .13% Lys, respectively. In Exp. 1, the additions of either Thr (.27%) or Met (.08%) to the 15% CP diet improved (P < .05) ADG and gain/feed (G/F); Trp (.04%) and Ile (.05%) additions had no effect. None of the 15% CP diets resulted in performance comparable to that obtained on the 21% CP diet. In Exp. 2, 19 and 17% CP diets fortified with Thr, Met, and Trp to obtain the digestible contents of the 21% CP diet produced performance equal to performance on the 21% CP diet. Results of Exp. 3 indicate that Thr (.11%) and Met (.08%) supplementation of the 17% CP diet were needed to maximize performance; Trp and Ile additions were not beneficial. Results of the final experiment suggested that Thr and Met additions to the 17% CP diet could be reduced to .05 and .04%, respectively, without lowering performance. These data indicate that a 17% CP, sorghum-soybean meal diet fortified with Lys, Met, and Thr can produce performance equal to that obtained by pigs fed a 21% CP diet.