Food mineral composition and acid–base balance in preterm infants

Background Due to a transient age-related low renal capacity for net acid excretion, preterm infants fed formula are at a considerable risk of spontaneously developing incipient late metabolic acidosis, clinically characterized by e.g., disturbed bone mineralization and impaired growth. Aim of the study From acid–base data in blood and urine under different diets of modified human milk or preterm formulas is attempted to explore the impact of food mineral (and protein) composition on renal regulation and systemic acid–base balance in preterm infants. Patients and methods Data were collected from 48 infants fed their own mother’s milk (28 native human milk, 20 enriched with fortifier) and 34 patients on formula (23 on a standard batch, 11 on a modified batch with reduced acid load). Intake of food was measured and acid–base data were determined in blood and timed-urine (8–12 h) samples. Results Differences in mineral composition of the diets led to considerable differences of daily “alkali-intake”, without significant effects on non-respiratory (base excess, BE) and respiratory (PCO₂) acid–base data in the blood. In contrast, a highly significant proportionality between individual dietary alkali intake and daily renal base (Na⁺ + K⁺–Cl⁻) excretion was observed (y = 0.32x−0.70, n = 80, r = 0.77, P < 0.0001), irrespective of the type of the diet. Conclusion Renal base saving mechanisms are normally effective in preterm infants to compensate for differences in dietary acid–base load. Generally, nutritional acid–base challenges can be judged much earlier and more safely by urinary than by blood acid–base analysis. Taking into account the age specific low capacity for renal NAE, the relatively high nutritional acid load of preterm standard formula should be reduced.     

Investigation of Effect of Nutritional Drink on Chemotherapy-Induced Mucosal Injury and Tumor Growth in an Established Animal Model

Chemotherapy-induced mucositis represents a significant burden to quality of life and healthcare costs, and may be improved through enhanced nutritional status. We first determined the safety of two nutritional drinks (plus placebo), and then potential gut protection in tumor-bearing rats in a model of methotrexate-induced mucositis. In study 1, animals were fed one of two test diets (or placebo or control chow pellets) for a total of 60 days and were monitored daily. All diets were found to be safe to administer. In study 2, after seven days of receiving diets, a Dark Agouti Mammary Adenocarcinoma (DAMA) was transplanted subcutaneously. Ten days after starting diets, animals had 2 mg/kg intramuscular methotrexate administered on two consecutive days; after this time, all animals were given soaked chow. Animals were monitored daily for changes in bodyweight, tumor burden and general health. Animals were killed 10, 12 and 16 days after initially starting diets, and tissues were collected at necropsy. In study 1, animals receiving diets had gained 0.8% and 10.8% of their starting bodyweight after 60 days, placebo animals 4.4%, and animals fed on standard chow had gained 15.1%. In study 2, there was no significant influence of test diet on bodyweight, organ weight, tumor burden or biochemical parameters. Only animals treated with MTX exhibited diarrhea, although animals receiving Diet A and Diet C showed a non-significant increase in incidence of diarrhea. Administration of these nutritional drinks did not improve symptoms of mucositis.     

Impact of an environmentally-realistic intake of cadmium on calcium,magnesium, and phosphate metabolism in bank voles,Clethrionomys glareolus

Oral intake of cadmium can disrupt calcium metabolism in laboratory rodents. If this occurs in free-living wild rodents, reproductive potential, growth, and survival could be adversely affected. This study investigated whether an environmentally-realistic intake of cadmium (1.5–1.7 mg/kg BW/24h) by bank voles, Clethrionomys glareolus, affected uptake and assimilation of calcium and also that of magnesium and phosphorus, two elements metabolized in close association with calcium. Mineral metabolism was monitored in bank voles fed four different diets; two diets were relatively low (0.12%) in calcium and contained either no cadmium (LC) or cadmium (LCCd), while the remainder were relatively high (0.74%) in calcium and also contained either no cadmium (HC) or cadmium (HCCd). Dietary calcium levels were varied because calcium can affect gut absorption of cadmium, and calcium levels in natural forage vary with habitat soil type.Cadmium had a significant effect on voles fed a low calcium diet. Animals given LCCd diet had significantly poorer calcium net gut absorption efficiency than animals fed the corresponding control (LC) diet and were in negative calcium balance, losing approximately 0.5–1% of body calcium reserves each day. In contrast, calcium inputs matched total outputs in animals fed the LC diet. Cadmium had no effect on net gut absorption of magnesium and phosphorus, but renal reabsorption and subsequent assimilation of these elements was greater in animals fed the LCCd diet than in those given the LC diet.Cadmium had no clear effect on macroelement metabolism in bank voles fed a diet relatively high in calcium. Net gut absorption and assimilation of calcium by voles fed the HCCd diet was reduced to the same extent as observed in animals fed the LCCd diet. However, because of their high dietary calcium intake, voles fed the HCCd diet maintained a positive calcium balance and there was no significant difference in calcium assimilation between animals fed the HCCd and HC diet. Cadmium had no effect on magnesium and phosphorus metabolism in voles fed high calcium diets.     

Protein hydrolysate vs free amino acid-based diets on the nutritional recovery of the starved rat

Summary Background and Aims To test the hypothesis that a peptide-based enteral product was equivalent to a low-fat, free amino acid-based formula in the nutritional and functional recovery of the starved rat. Methods Sixteen male Wistar rats were starved for 3 days. Then, rats were randomised to a whey protein hydrolysate-based diet or a free amino acid-based diet and refed for 3 days. The experiment was designed to provide the same energy intake in both groups. The parameters studied included body weight gain, nitrogen retention, plasma free amino acid concentrations, muscle glutamine concentrations and glutathione levels in gut mucosa and liver. Results Weight gain was statistically higher on the peptide-based diet than on the elemental diet after rhe refeeding period. This difference in weight gain was associated with a statistically higher nitrogen retention. Plasma and muscle free glutamine concentrations were higher in rats fed the whey protein hydrolysate-based diet than those in rat refed the free amino acid-based diet, even though the glutamine intake was higher in the latter group. Glutathione concentrations in liver and gut mucosa were similar in the groups. Conclusion We conclude that enteral diets containing peptides were more effective than a diet containing free amino acids in the nutritional recovery of the starved rat. Received: 17 May 2000, Accepted: 1 September 2000     

Nutritional and technological evaluation of an enzymatically methionine-enriched soy protein for infant enteral formulas

Enzymatically modified soy proteins have the amino acid profile and functional properties required for dietary support. The objective of this study was to evaluate the nutritional and technological properties of an enzymatically modified soy protein ultrafiltered fraction with bound methionine (F(1-10)E) to be used as a protein ingredient for infant enteral formulas. F(1-10)E was chemically characterized and biologically evaluated. Thirty-six weaning Wistar rats were fed during 3 weeks with a 4% casein-containing diet. Rats were divided into three groups and recovered for 3 weeks with 18% protein-containing diets based on: (1) F(1-10)E, (2) casein or (3) soy isolate+methionine. Nutritional indicators were weight gain, protein efficiency ratio, plasma proteins, apparent digestibility and protein in the carcass. Additionally, F(1-10)E was added as a protein ingredient of an enteral formula, and its sensory and rheological properties were compared with a hydrolyzed-whey protein commercial formula. F(1-10)E contained 68% protein and 5% sulphur amino acids, with 60% of peptides 0.05) in weight gain (108 g and 118 g, respectively), protein efficiency ratio (2.7), apparent digestibility (93% and 95%), plasma proteins (5.7 mg/100 ml) and carcass protein (61%), and better than soy isolate-based+methionine diet (P<0.05). Viscosity of the commercial formula and our formula was similar during a 24-h period. Sensory acceptability was 8 for our formula and 3.5 for the commercial one, on a scale of 1-10 (P<0.05). Due to its nutritional, sensorial and rheological properties, F(1-10)E could be used as a protein source in infant enteral formulas.     

Dietary glycomacropeptide supports growth and reduces the concentrations of phenylalanine in plasma and brain in a murine model of phenylketonuria

Phenylketonuria (PKU) is a genetic disorder caused by deficiency of phenylalanine hydroxylase (PAH) that requires life-long adherence to a low-phenylalanine (Phe) diet. Glycomacropeptide (GMP) is uniquely suited to the nutritional management of PKU, because pure GMP contains no Phe. Our aim was to assess how ingestion of diets containing GMP support growth and affect the concentrations of amino acids in plasma and brains of mice with a deficiency of PAH, the Pah(enu2) mouse (PKU mouse). Experiments were conducted in 4- to 6-wk-old wild-type (WT) (C57Bl/6) and PKU mice fed diets containing 20% protein from casein, amino acids, or GMP supplemented with limiting indispensable amino acids (IAA). PKU mice fed the GMP diet showed gains in body weight, feed efficiency, and a protein efficiency ratio that did not differ from the amino acid diet. The concentrations of isoleucine and threonine in plasma showed a significant 2- to 3-fold increase for WT and PKU mice fed GMP compared with casein or amino acid diets, respectively. PKU mice fed the GMP diet had decreased concentrations of Phe in plasma (11% decrease) and in 5 regions of the brain (20% decrease) compared with the amino acid diet. The concentration of Phe in the brain was inversely correlated with the concentrations of isoleucine, threonine, and valine in plasma (R2 = 0.74; P < 0.0001), suggesting competitive inhibition of Phe transport into the brain. In summary, PKU mice fed GMP showed comparable growth and reduced concentrations of Phe in plasma and the brain compared with an amino acid diet. These data support the use of GMP supplemented with IAA as an alternative source of dietary protein for individuals with PKU.     

Hepatic cysteine dioxygenase activity and sulfur amino acid metabolism in rats: possible indicators in the evaluation of protein quality

Experiments were carried out to examine the possibility that the sulfur amino acid metabolism of rats may be an indicator of the nutritional value of dietary protein. Rats were fed diets containing 8, 16 or 24% of gluten, soy protein or casein for 3 wk. Hepatic cysteine dioxygenase activity, hepatic concentration of glutathione, cysteine and taurine and urinary taurine were examined. In addition, the sulfur amino acid metabolism of rats fed these diets fortified with the appropriate first limiting amino acid for 7 d was also examined. High urinary taurine excretion was observed in the three gluten groups, whereas very low urinary taurine excretion was observed with up to 24% soy protein or up to 16% casein. The hepatic hepatic cysteine dioxygenase activities of the gluten diet groups were higher than those of corresponding soy protein or casein diet groups, except that of rats fed the 24% casein diet. The hepatic concentrations of both glutathione and cysteine in gluten diet groups were also higher than those of corresponding soy protein or casein diet groups, except 24% soy protein and 16 and 24% casein diet groups. In rats fed the casein or soy protein diets urinary taurine excretion and hepatic cysteine dioxygenase activity increased with increasing methionine supplementation, the first limiting amino acid. Conversely, in rats fed the gluten diet both urinary taurine excretion and hepatic cysteine dioxygenase activity decreased with increasing lysine supplementation, the first limiting amino acid. These findings suggest that urinary taurine excretion and hepatic cysteine dioxygenase activity may be useful as sensitive indicators of the nutritional value of dietary protein.     

Vegetable proteins enhance the growth of milk-fed piglets, despite lower apparent ileal digestibility

This experiment compared the replacement of whey protein with isolated soy protein (ISP), or 2 levels of a hydrolyzed vegetable protein mixture (Lo HVPM and Hi HVPM, containing a partially hydrolyzed blend of soy, wheat, and other proteins) in liquid milk-replacer diets fed to neonatal pigs from 2 to 19 d of age. Piglets fed the vegetable protein diets weighed 20% more (8179 +/- 211 g, P < 0.05) at the end of the study than piglets fed the whey diet (6805 +/- 244 g). Growth rates were 35% higher for piglets fed the Hi HVPM diet than for piglets fed the whey diet. Similarly, intakes of the vegetable protein diets exceeded that for the whey diet (P < 0.05). Although the apparent ileal digestibilities of most amino acids were greater for the whey diet, digestible amino acid intakes (especially Arg, Phe, Met, and His) were greater in pigs fed the Hi HVPM and ISP diets (P < 0.01). Furthermore, carcasses of piglets fed the whey diet contained a higher percentage of fat and ash, whereas piglets fed the vegetable protein-containing diets accreted protein 42% faster (P < 0.01). Villus height and area and leucine aminopeptidase activity in the small intestine were greater in piglets fed the Lo HVPM diet than in those fed the ISP diet. Collectively, these data support the conclusion that some processed vegetable proteins may be good alternatives to whey protein in liquid diets formulated for neonatal pigs and that an appropriate balance of amino acids is more important than the source of protein per se.     

Amino Acid-Based Diet Prevents Lethal Infectious Diarrhea by Maintaining Body Water Balance in a Murine Citrobacter rodentium Infection Model

Infectious diarrhea is one of the most important health problems worldwide. Although nutritional status influences the clinical manifestation of various enteric pathogen infections, the effect of diet on enteric infectious diseases remains unclear. Using a fatal infectious diarrheal model, we found that an amino acid-based diet (AD) protected susceptible mice infected with the enteric pathogen Citrobacter rodentium. While the mice fed other diets, including a regular diet, were highly susceptible to C. rodentium infection, AD-fed mice had an increased survival rate. An AD did not suppress C. rodentium colonization or intestinal damage; instead, it prevented diarrhea-induced dehydration by increasing water intake. An AD altered the plasma and fecal amino acid levels and changed the gut microbiota composition. Treatment with glutamate, whose level was increased in the plasma and feces of AD-fed mice, promoted water intake and improved the survival of C. rodentium-infected mice. Thus, an AD changes the systemic amino acid balance and protects against lethal infectious diarrhea by maintaining total body water content.     

Some aspects of bile acid and urobilinogen excretion and fecal elimination in men given a rural Guatemalan diet and egg formulas with and without added oat bran.

Six healthy men were fed a formula diet with and without oat bran and a natural food diet typical of rural Guatemala. No significant difference in dye transit time was found between diets but the Guatemalan diet significantly decreased dye retention time and increased stool frequency. Serum cholesterol and triglyceride levels showed no significant differences among dietary treatments. Excretion of fecal bile acids significantly increased on the Guatemalan and oat bran diets, but fecal bile acid concentration was significantly lower only on the Guatemalan diet. Urinary urobilinogen excretion and fecal urobilinogen concentration were significantly lower with the Guatemalan diet.     

Effects of fructo-oligosaccharide on DSS-induced colitis differ in mice fed nonpurified and purified diets

We investigated whether feeding a purified compared with nonpurified diet supplemented with or without fructo-oligosaccharide (FOS; 50 g/kg diet) altered the response of C57BL/6 mice to DSS-induced diarrhea. In Expt. 1, we examined disease severity in mice receiving DSS (2% in drinking water) for 5 d. In Expt. 2, we measured cecal organic acid concentrations and fecal water-holding capacity (WHC). In Expts. 3 and 4, we tested whether polycarbophil calcium (PC), a water-absorbing polymer, altered fecal WHC and disease severity. FOS exacerbated diarrhea and weight loss in mice fed the purified diet and reduced fecal bleeding in mice fed the nonpurified diet (P < 0.05). Without DSS administration, cecal acetate and butyrate concentrations were higher in mice fed the nonpurified diet than in mice fed the purified diet (P < 0.05). Fecal WHC was higher in mice fed the nonpurified diet than in mice fed the purified diet (P < 0.05). One day after starting DSS administration, cecal succinate concentrations were higher in mice fed the FOS-supplemented purified diet than in mice fed the other 3 diets, whereas SCFA concentrations were higher in mice fed the nonpurified diet than in mice fed the purified diet (P < 0.05). PC supplementation increased fecal WHC and prevented FOS exacerbation of diarrhea in mice fed the purified diet (P < 0.05). We conclude that the effects of FOS on DSS-induced diarrhea differ in mice fed the purified and nonpurified diets. The protective effect of nonpurified diet was associated with increased production of organic acids and WHC in the intestinal contents.     

Dietary marine algae (Schizochytrium sp.) increases concentrations of conjugated linoleic, docosahexaenoic and transvaccenic acids in milk of dairy cows.

Modification of milk fat to contain long-chain (n-3) fatty acids and increased concentrations of conjugated linoleic acid has potential for improving health of consumers. Natural modification of milk through nutritional manipulation of diets for dairy cows is preferable to post-harvest modification. The objectives of this study were to increase the concentrations of beneficial fatty acids in milk fat by feeding a diet rich in (n-3) fatty acids from algae to dairy cows. Cows were fed a control diet, a diet containing algae (Schizochytrium sp.) protected against ruminal biohydrogenation, or a diet containing unprotected algae for 6 wk. Feed intake and milk production were recorded daily. Milk samples were obtained weekly for analysis of milk composition and profile of fatty acids. Percentage of fat in milk of cows fed algae was lower (P < 0.01) than in milk from cows fed the control diet; however, energy-corrected milk production did not differ (P > 0.05). Inclusion of algae in diets decreased (P < 0.01) feed intake. Milk fat from cows fed algae contained greater (P < 0.01) concentrations of conjugated linoleic acid, (n-3) fatty acids (particularly docosahexaenoic acid), and transvaccenic acid. Concentrations of docosahexaenoic acid were greater (P < 0.01) in milk fat from cows fed protected algae compared to milk fat from cows fed unprotected algae. Milk fat from cows fed algae contained lower (P < 0.05) concentrations of total saturated fatty acids compared to cows fed the control diet. In conclusion, milk fat can be modified through nutritional management of dairy cows to provide more favorable fatty acids for consumers.     

Persistent diarrhoea syndrome

Persistent diarrhea (PD) is 3 or more stools/day which lasts nonstop for 14 days. Some small intestine disorders impede its diagnosis. PD follows 3-20% of acute diarrhea cases. It is more difficult to treat than acute diarrhea and often brings about nutritional and metabolic complications, e.g., growth failure. Skin infection, systemic infection, and micronutrient deficiency often accompany PD so it is often referred to PD syndrome (PDS). PDS patients often have more frequent recurrences of diarrhea although not of PD. Deaths of hospitalized PDS patients range from 10-12% and most occur within the 1st 48 hours. Physicians should immediately follow the guidelines for managing sepsis dehydration, fever, hypoglycemia, and malnutrition when 1st treating a hospitalized PDS patient. They should then start broad spectrum antibiotics. Once stable, nutrition management can begin. This includes maintaining breast feeding or using expressed breast milk, a digestible balanced diet free of allergenic proteins, and additional micronutrients and vitamins. Upon arrival at home, the child should eat a high energy high protein diet. PDS most often occurs in young infants, e.g., peaking at 7 months in Bangladesh. Other risk factors include nonbreast feeding, recent antibiotic therapy, history of bloody diarrhea, vitamin A deficiency, and malnutrition. Giardia lamblia and aggregative, enterotoxigenic Escherichia coli in the stool have been associated with PDS, but have not yet been identified as causative agents. Scientists surmise that PDS is caused by an insult to the intestine which allows the passage of proteins, especially dietary proteins, through the mucosa thereby inducing a hypersensitive reaction which causes more mucosal damage. Excess bacterial growth plays a role in production of an irritant product which contributes to fluid loss.     

Lyophilized carrot ingestion lowers lipemia and beneficially affects cholesterol metabolism in cholesterol–fed C57BL/6J mice

Summary Background Several lines of evidence indicate that diet rich in fruit and vegetable can protect against cardiovascular diseases by acting on cholesterol metabolism and on oxidative stress. Aim of the study The aim of this study was to assess whether daily carrot consumption (provided as lyophilized powder) could differentially influence the consequences of cholesterol supplementation on lipid metabolism and oxidative stress in C57BL/6J mice. Methods Fourteen mice were randomized in four groups. Mice were fed either control diets (without or with 0.25% cholesterol added) or lyophilized carrot enriched diets (20% wt/wt without or with 0.25 % cholesterol added) for 4 weeks. Cholesterol and triglycerides in plasma and in liver were measured at the end of the experimental period. Fecal excretion of sterols was evaluated. Vitamin E and carotenoid concentrations were also determined. Several biomarkers relative to oxidative stress such as FRAP (Ferric Reducing Ability of Plasma) and isoprostanes were investigated. Results Feeding the carrot diet resulted in a decrease of cholesterol (–41%) and triglycerides (–49 %) in plasma and in the liver (–41% and –39%, respectively) in animals fed cholesterol–supplemented diets. Carrot diet induced an increase of total neutral sterols fecal excretion, which inhibits digestive cholesterol absorption. Carrot diet increased antioxidant status in cholesterolfed mice as related by the 16% higher FRAP values. Although vitamin E was not affected by carrot diet, vitamin E/TG ratio was significantly higher in animals fed carrot diets. The carrot diet induced an increase of vitamin E in the heart in both cholesterol–free and cholesterol–supplemented mice suggesting a higher protection of this tissue. Conclusion This study shows that carrot ingestion decreases lipemia and improves antioxidant status in mice. Such results suggest that carrot intake may exert a protective impact against CVD linked to atherosclerosis. It is likely that these effects could be due to the synergistic effect of fiber and associated antioxidants.     

Comparative effects of protein, protein hydrolysate and amino acid diets on nitrogen metabolism of normal, protein-deficient, gastrectomized or hepatectomized rats

The effects of diets containing protein, protein hydrolysate or an amino acid mixture on nitrogen metabolism of normal and severely protein-deficient rats and on rats after gastrectomy and hepatectomy were compared. In experiment 1, rats weighing about 80 g were fed one of three experimental diets containing casein, protein hydrolysate or an amino acid mixture for 28 d. In experiment 2, rats weighing about 270 g were fed a protein-free diet for 40 d, and then one of the above three experimental diets for 14 d. In experiment 3, rats weighing about 220 g were totally gastrectomized and fed one of the three experimental diets for 21 d. In experiment 4, rats weighing about 210 g had about 70% of the liver resected, and then were fed one of the three experimental diets for 15 d. In all four experiments, daily food intake, daily body weight gain, nitrogen balance, urinary nitrogen compounds, body composition and hematologic values were measured. In normal, protein-deficient and hepatectomized rats, most results were similar for the groups fed protein, protein hydrolysate or amino acid diets, except that urinary ammonia was higher in the group fed the amino acid diet than in the other two groups. For about 10 d after total gastrectomy, food intake and growth of the animals fed the protein diet were lower than in the other two groups.     

三种维生素对仔鸡发育及组织维生素含量的影响

目的：　研究日粮维生素Ａ（ＶＡ）、维生素Ｄ（ＶＤ）、维生素Ｅ（ＶＥ）在营养方面的相互影响。方法：　在基础日粮中添加不同剂量的维生素组成试验日粮进行动物试验,测定肉鸡的增重、饲料转化率和组织维生素含量。　结果：　当饲粮ＶＥ含量为２０ ＩＵ／ｋｇ 时,采食每千克饲粮添加２０ ０００ＩＵ ＶＡ的仔鸡增重显著低于采食每千克饲粮添加１ ５００ＩＵ 的仔鸡（Ｐ＜ ０．０５）;高ＶＡ组鸡的血浆和肝脏ＶＥ含量非常显著低于低ＶＡ组（Ｐ＜ ０．０１）,表明日粮高水平ＶＡ可能抑ＶＥ的吸收;当饲粮ＶＡ含量为３０ ０００ＩＵ／ｋｇ、ＶＥ为２０ＩＵ／ｋｇ 时,随ＶＤ水平极度提高,雏鸡体重呈下降趋势。而饲粮ＶＤ含量为２００ＩＵ和１ ０００ＩＵ／ｋｇ 对鸡生长及血液和肝脏ＶＡ、ＶＥ含量无显著性影响;当ＶＥ水平提高到２００ ＩＵ／ｋｇ,ＶＤ水平提高到８ ０００ ＩＵ／ｋｇ 时,雏鸡体重显著增加（Ｐ＜ ０．０５）;在相同ＶＤ水平下,高水平ＶＥ日粮组试鸡的体重均高于低水平日粮组。结论：日粮ＶＡ、ＶＤ和ＶＥ间存在着显著的相互影响,在配制动物日粮时应注意ＶＡ、Ｄ和Ｅ的适宜比例关系。     

Beneficial effect of amino acid supplementation, especially cysteine, on body nitrogen economy in septic rats

BACKGROUND AND AIMS: Muscle wasting and increased synthesis of proteins and compounds involved in host defense characterize severe injury. The aims of the studies reported were to determine which amino acids exhibited an increased tissue content linked to anabolic processes in infected rats by comparison with healthy pair-fed controls, and to explore whether diets supplemented with these amino acids attenuate the catabolic response to infection. METHODS: Total amino acid content of the liver and the rest of the body were measured in control well-fed rats, in infected rats and their pair-fed controls 2 days after infection. In the nutritional protocols, infected rats were fed with a diet supplemented with alanine (basal diet), or threonine, serine, aspartate, asparagine and arginine (AA) or AA+cysteine (complete diet). RESULTS: Infection significantly increased liver total amino acid content by 38% for most amino acids. In contrast, the percentage increase was cysteine 79.3, threonine 45.3, aspartate-asparagine 46.3 and serine 46.5. Whole body without liver content of most amino acids decreased after infection due to the catabolic response, while the content of cysteine increased by 6% (P<0.05) and those of threonine and arginine did not decrease. After infection, animals fed the complete diet lost less weight than animals fed the basal diet (P<0.05). Furthermore, AA plus cysteine supplementation reduced significantly urinary nitrogen excretion and muscle wasting. CONCLUSIONS: The results provide evidence that diet supplementation with cysteine, threonine, serine, aspartate-asparagine and arginine supports the synthesis of vital proteins to spare body protein catabolism during infection.     

Absorption and tissue distribution of zinc, iron and copper by rats fed diets containing lactalbumin, soy and supplemental sulfur-containing amino acids

Zinc, copper and iron utilization was examined in rats fed diets containing 30% lactalbumin (L); 30% soy assay protein (S) or 30% soy assay protein supplemented with 0.26% cysteine (SC), 0.45% methionine (SM), 0.26% cysteine and 0.45% methionine (SCM) or 0.71% cysteine (SXC). Diets L, SC and SCM contained equal amounts of cysteine; diets L, SM and SCM contained equal amounts of methionine; diets L, SCM, SXC contained equal amounts of sulfur-containing amino acids. Rats fed diet L had significantly higher levels of zinc in tibias, kidneys and plasma; higher levels of copper in kidneys; and higher levels of iron in tibias than rats fed diet S. Rats fed diet L also absorbed (apparent and true) significantly more zinc; excreted significantly more zinc of endogenous origin in the feces; and absorbed (apparent) significantly less copper than rats fed diet S. Rats fed the soy diets supplemented with sulfur-containing amino acids, especially diet SXC, tended to have elevated levels of zinc in their tibias and kidneys and greater apparent and true absorptions of zinc than rats fed diet S. Rats fed diet SXC still had significantly lower zinc levels in tissue than rats fed diet L. Apparent absorption of zinc was similar among rats fed diets L, SCM and SXC.     

Nitrogen source primarily supplied by amino acids and the efficacy for maximal growth of rats.

The effect of osmotic pressure of diets on be food intake of young rats was investigated by comparing the nutritional effect of casein with the corresponding amino acid mixture at 3.2% nitrogen level. Changes in the osmolarity of diets due to the type of dietary carbohydrate had a little effect on food intake, whereas partial substitution of casein for amino acids resulted in significant increase in food intake. Weight gain and food intake of rats fed the 25% replaced amino acid diet were compared with those of rats fed the casein diet. Food intake was lower at 12.5% replacement than at 25% replacement. These observation suggest that a well-balanced amino acid mixture supported maximal growth of rats when 25% of the amino acid mixture was replace with casein. This suggestion could be experimentally confirmed by using an amino acid mixture based on the amino acid composition of whole-egg protein.     

Early Infant Formula Feeding Impacts Urinary Metabolite Profile at 3 Months of Age

There is a growing consensus that nutritional programming may persist and influence risk for several chronic diseases in adulthood. In the present study, we used urinary metabolic analysis in assessing diet effects on early-life metabolism. Urine samples from healthy three-month-old infants fed human milk (HM; n = 93), cow’s milk-based infant formula [MF; n = 80], or soy protein-based infant formula (SF; n = 76) were analyzed with an untargeted metabolomics approach using GC-TOF MS. PLS-DA and ANOVA analyses were performed using MetaboAnalyst (v4.0). A total of 150 metabolites differed significantly among the feeding groups, including dietary-specific patterns of urinary metabolites of sugars, sugar alcohols, amino acids, and polyphenols. Urinary metabolites may mirror the infant’s overall metabolism and serve as a noninvasive tool to examine the neonatal effects of diet on early-infant metabolism.