Dietary Hydrolysate Research Articles

Bacterial contamination and growth in two defined formula diets of different pH

We inoculated partially hydrolysed protein feed of low pH and an intact protein feed of neutral pH with various pathogenic bacteria, and showed that the low pH feed restricted bacterial growth. To study this effect in a clinical setting, 20 malnourished in-patients were randomised prospectively to receive one or other of these feeds. Both formulae were given as a continuous feed via a nasogastric tube, 1,000 ml over 12 h twice daily, using routine hygienic measures. On two occasions significant contamination was demonstrated ( Erwinia herbicola and Acinetobacter Iwoffi), both occurring in the intact protein diet. When the bacteria were isolated and transferred to the hydrolysed protein diet, their growth was inhibited. The contamination did not cause clinical complications. The study demonstrates inhibition of microbial growth in a partially hydrolysed protein formula of low pH. This effect may reduce the risk of contamination, and limit infectious complications.

Efficiency of enteral nitrogen support in surgical patients: small peptides v non-degraded proteins.

In a prospective study, 12 intensive care patients, after abdominal surgery, received three alternate six-day courses of two enteral diets with identical nitrogen (0.3 g N/kg per day) and energy (60 kcal/kg per day) supply. The protein hydrolysate (PH) diet contained enzyme-hydrolysed casein and lactoserum (60% small peptides), while the non-degraded protein (NDP) diet contained a nitrogen source of similar amino acid composition, but in the form of non-degraded proteins. The patients were randomised to receive either PH-NDP-PH or NDP-PH-NDP. Parameters reflecting protein metabolism were assessed in the plasma, urine, and stomal effluent on days 1, 6, 12, and 18, three hours after stopping the nutrition (t0), and one hour after restarting it (t1). Comparisons of t1 and t0 values showed that 13 amino acids (including the eight essential amino acids) increased significantly with the protein hydrolysate diet, but only two increased with the non-degraded protein diet. Similarly, with protein hydrolysate, insulin-aemia at t1 was significantly higher than at t0 and correlated with plasma leucine, phenylalanine, alanine, and lysine concentrations. In addition, significant improvements in plasma albumin, transferrin, and retinol binding protein concentrations were seen with protein hydrolysate, together with a significant decrease in the plasma phenylalanine/tyrosine ratio and urinary 3-methylhistidine excretion. We conclude that in patients in intensive care after abdominal surgery enteral support containing small peptides is more effective than an equivalent diet containing whole proteins in restoring plasma amino acid and protein levels.

Larval Diets from Different Protein Sources for Mediterranean Fruit Flies (Diptera: Tephritidae)

The effects of larval diets with different protein sources were investigated on the development of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann). Casein, corn hydrolysate, soy protein, soy hydrolysate, yeast hydrolysate, lactoalbumin, lactoalbumin hydrolysate, and wheat gluten were tested as replacements for torula yeast. Flies raised on soy hydrolysate had the highest pupation (63%), pupal weight (11.2 mg), days to pupation (9.1 days), and least percentage eclosion (92.8%). Larvae failed to pupate when fed the corn hydrolysate diet. Pupal weight increased with protein levels, fitting to the regression model y = 5.5(ln x)0.5; after a rapid increase, pupal weight leveled off with further increases beyond 5% dietary protein. Protein source and protein concentration affected pupal color; anomalous white pupae resulted from larvae reared on diets containing casein, soy protein, and lactoalbumin at a protein concentration of 3.6%. Increasing the dietary levels of casein, soy protein, and lactoalbumin above 3.6% resulted in normal brown pupae.

Effect of Orally Administered 5-Ethoxy-6-[4-Methoxyphenyl] Methyl-1,3-Benzodioxole on Reproduction of the Mediterranean Fruit Fly (Diptera: Tephritidae)

Ovarian growth was delayed at least 25 d in females of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), fed sugar cubes containing J2581 (5-ethoxy-6-[4-methoxyphenyl]methyl-1,3-benzodioxole) at a concentration of 0.57 mg/g. Ovarian development of females fed a sugar-protein hydrolysate diet containing the same concentration of J2581 was delayed by 9 d. Egg hatch (larval eclosion) was significantly reduced from 0 to 6%. Eggs that failed to hatch had fragmented yolk plasm and absence of embryonic development. Ajuvenile hormone analog, (7S)methoprene, concomitantly fed with J2581 to newly emerged flies, caused partially increased oviposition but no improvement in ovarian growth or percentage egg hatch. J2581 and seven other benzyl-1,3-benzodioxoles were not mutagenic in the Ames Salmonella microsome test with and without metabolic activators.

Reduction of 24‐Hour Gastric Acidity by Different Dietary Regimens: A Randomized Controlled Study in Healthy Volunteers

Evidence from animal experiments suggests that intraduodenal infusion of nutrients leads to an inhibition of gastric acid secretion via an enterogastric feedback mechanism. Detailed data are lacking, however, on the difference in circadian gastric acidity between gastric and intraduodenal alimentation in man. We conducted a randomized study in 10 healthy volunteers (5 men, 5 women, age 22-30 yr). From 8:00 am of the first study day until 4:00 pm of the next day, either a standardized normal meal or a liquid polymer diet (Fresubin) was given orally at 8:00 am, noon, and 6:00 pm. In a third experiment, a liquid hydrolysed diet (Survimed OPD) was continuously applied to the duodenum using a portable pump. Daily caloric intake and main nutrient components were comparable in all three diets. From 2:00 pm of the first day until 4:00 pm of the next day, an intragastric pH-metry was performed with a combined glass pH-electrode in the gastric corpus. Median pH-values from predefined time periods (whole day, prandial, interdigestive, nocturnal) were compared between the three groups. The orally applied liquid polymer diet led to a significantly stronger increase in 24-hr and prandial gastric pH than the normal diet. Twenty-four-hr, interdigestive, and nocturnal pH-median values were significantly higher during continuous intraduodenal application of the liquid hydrolysed diet than during the normal diet.

Hormonal responses to complete or hydrolyzed protein diets in patients after upper gastrointestinal surgery.

Six gastrointestinal hormones were measured in the plasma of six healthy controls and long-term changes were evaluated in six patients 2-20 years after upper gastrointestinal surgery. In a metabolic unit study we determined fasting hormonal levels, the time to peak hormonal response, and a 135-minute hormonal response to the meal. Test meals were isocaloric, 500 kcal, and isonitrogenous, consisting either of natural breakfast components or of complete liquid diets with intact protein (Ensure) or hydrolyzed protein (Vital). Postsurgical subjects were in good health and had no postcibal complaints. Nevertheless, their hemoglobin and serum albumin were significantly lower than in controls. Postsurgical subjects had higher fasting gastrin (121.3 +/- 11.6 vs 65.4 +/- 6.6 pg/ml, P less than .01) and motilin (148.7 +/- 32.9 vs 70.4 +/- 13.1 pg/ml, P less than .05) than controls. In postsurgical patients the peak gastrin and pancreatic glucagon responses to meals were obtained in significantly shorter time. Their total response to motilin and secretin to meals was significantly lower than in controls. Fasting glucose and the meal-induced responses of insulin and vasoactive intestinal polypeptide were not different from controls. The nature of dietary protein did not significantly affect hormonal responses to feeding. We conclude that gastrointestinal hormonal changes persist many years after surgery. These changes are probably related to faster transit of meals with a generally weaker total hormonal response to feeding. Although these differences from normal may be nutritionally well compensated, they may become important in periods of metabolic stress.

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.

Effect of liquid nutrients on the development and reproduction of the predacious miteAmblyseius gossipi(mesostigmata: Phytoseiidae)

Abstract The facultative predacious mite, Amblyseius gossipi El-Badry was able to develop, survive and reproduce on molasses, royal jelly and yeast hydrolysate diets. Compared with a palm tree pollen grain diet, the maximum number of individuals attaining maturity was on royal jelly or a combination of royal jelly and molasses. The duration of the development time, from larva to adult, was twice as long as that on pollen grains. The maximum reproduction/female/day was recorded on royal jelly and molasses or their combination and the minimum on yeast hydrolysate. Individuals neither developed nor reproduced on clean plant leaves.

Reduction of serum phenylalanine levels in PKU rats with intestinal absorption inhibitors of phenylalanine (PHE): 61

It has been often suggested that inhibition of the intestinal absorption of PHE would be a new approach for PKU treatment. We have previously shown that a PKU model for dietetic studies is obtained by means of the synergistic inhibition of Phenylalanine-Hydroxylase with p-chlorophenylalanine + cotrimoxazole (daily intraperitoneal injection of the 2 inhibitors leads to hyperphenylalaninemia without need for a phenylalanine load). Addition of beta-2-thienylalanine (THI) or phenylalaninol (PHE-ol) to the diet (1g%) significantly reduced phenylalaninemia: PHE: 1.30 ± 0.30, + THI : 0.70 ± 0.27, + PHE-ol:0.87 + 0.29 mmol/l. However, the effectiveness of THI or PHE-ol was mainly dependent on diet quality: with 5 isonitrogenous-isoosmotic diets (amino acids, lactalbumin & its hydrolysate, casein & its hydrolysate), decrease of serum PHE with THI or PHE-ol only occurred with high PHE diets (inhibitor/PHE molar ratio 1.4), without significant difference between results with intact or hydrolysed protein diets. It has been claimed that amino acid (AA) changes in serum, liver and brain, induced by hyperPHE, could explain disturbed protein synthesis in PKU; we confirm such changes in our PKU model (mainly: essential AA decrease in serum, liver and brain), however AA imbalance did not disappear on THI or PHE-ol supplemented diets. These data suggest that PHE analogues (such THI or PHE-ol)used in diets to decrease intestinal absorption of PHE cannot ensure serum PHE reduction comparable to that obtained with PHE restricted diets.

Liquid Protein Diets and Electrolyte Deficiency

To the Editor.— The Journal had two articles (240:115, 1978; 240:120, 1978) and an editorial (240:144, 1978) referring to patients who followed 300-calorie, protein hydrolysate diets and experienced remarkably similar illnesses: syncopal episodes, hypotension, prolonged Q-T interval, and low QRS voltage. In addition, three of the four died of arrhythmias. The hospital's normal values were not listed for potassium and magnesium, but Singh et al (240:115, 1978) mentioned that the electrolyte levels were marginally depressed. Comment was made that one patient received magnesium orally while in an intensive care unit. Another received one ampul of magnesium and died 2 1/2 days later without receiving any more. This patient had also taken a parenteral-mineral preparation containing magnesium, which can vary from 0.15 to 100 mg, depending on the particular one selected. There was no explanation for the omission of the milliequivalents of these items, but it is unlikely that the patients

A preliminary investigation of the effects of diets on lesion formation in the hindgut of adult female American cockroaches

A preliminary investigation of the general relationships between different levels and sources of dietary nitrogen and lesion formation in the alimentary canal of adult female American cockroaches, Periplaneta americana (L.), has been conducted. Increasing levels of casein protein in the diet could not be clearly correlated with an increased incidence of lesions, but very high casein protein levels produced gross tissue abnormalities in the hindgut. Diets containing casein hydrolysate appeared to enhance lesion formation. When 1% additions of kynurenic acid, xanthurenic acid, tryptophan, and uric acid were made as supplemental sources of nitrogen, lesions appeared in a greater number of animals. Except in the case of uric acid, these spiked diets resulted in a lower total lesion area than when the nitrogen source was casein hydrolysate alone. Additions of an antibiotic, neomycin, to casein hydrolysate diets resulted in a lower level of lesion-forming activities.Lesion formation which was enhanced by dietary means appeared to result from an inflammatory reaction involving hemocytes. It is proposed that these inflammations were caused by high ammonia concentrations and irritant bacterial metabolites present in the gut lumen. No evidence was found to indicate that oxyuroid nematodes contributed to hindgut lesion formation.

Modifications of Adult Olive Fruit Fly Diet to Control the Production of Mottled Eggs and to Increase Fecundity1

The addition of 0.25% Vanderzant’s vitamin mixture and 0.05% cholesterol to the sucrose and yeast hydrolysate diet of adult females of Dacus oleae (Gmelin) can both inhibit the production of mottled eggs and increase fecundity. Yeast hydrolysate renders the diet unpalatable and deliquescent, but an upper limit of ca. 23% by weight results in optimal egg production. Two dry diets were developed. Neither contained an antibiotic and both were readily prepared. Each diet prevented the production of mottled eggs, maintained hatchability at over 75%, and out-performed the standard, wet-mixed, fresh-egg-yolk diet when measured by the average number of eggs per female per day (standard diet, 9.4; diet 14,12.2; and diet 15,14.2).

Further observations on trypsinogen deficiency disease: Report of a second case

A second infant with trypsinogen deficiency disease is described. The infant presented with severe hypoproteinemia, edema, anemia, and growth failure, and subsequently developed dyspigmentation of the hair. The clinical abnormalities and their dramatic response to protein hydrolysate diet are strikingly similar to those of the first patient described. The finding of a second case unrelated to the first in a single community suggests that trypsinogen deficiency disease is probably not a rare disease. Since it is a treatable disorder, it is important to consider it in the differential diagnosis of any infant with hypoproteinemia, edema, and failure to thrive.

Effect of Dietary Amino Acid Source on the Zinc-deficiency Syndrome in the Chick

The objective of these studies was to compare isolated soybean protein, casein hydrolysate and dried egg white as amino acid sources in chick diets varying in zinc content. Compared with isolated soybean protein in low zinc diets for chicks, casein hydrolysate and dried egg white produced severe zinc deficiency, but the chicks did not develop leg abnormalities, and tibias and femurs of the chicks had higher concentrations of zinc, ash and fat and less water. The length-to-width ratios of femurs from zinc-deficient chicks fed casein hydrolysate or egg white were much greater than for chicks fed zinc-deficient soy protein diets. Dietary amino acid source had no effect on the zinc content of heart, liver or muscle. Supplements of Mn, inorganic P, vitamin D3, cod liver oil, or a mixture of 13 additional trace elements had no effect on the zinc-deficiency syndrome in chicks fed soy protein. Autoclaving the soy protein or adding 80 ppm Cu had slight beneficial effects, whereas doubling of the mineral mix had slight detrimental effects on the zinc-deficient chick fed soy protein. HEDTA in a soy protein diet containing 12 ppm zinc overcame all zinc-deficiency symptoms. Addition of phytic acid in amounts comparable to those in soy protein to egg white and casein hydrolysate diets caused little or no depression in zinc availability and caused no leg abnormalities. It appears that soy protein contains a complicating factor other than phytic acid which affects zinc metabolism, especially in bone.

Dietary Regulation of Pancreatic Enzyme Synthesis, Secretion and Inactivation in the Rat

Dietary regulation of the synthesis, secretion and inactivation of trypsin, chymotrypsin and amylase was studied in rats fed a nitrogen-free ration or diets containing casein, whole-egg protein or hydrolysates of these proteins. Measurements of the enzyme content of the pancreas after an 11-hour fast showed that substitution of the nitrogen-free diet for the casein diet depressed synthesis of the 3 enzymes, whereas replacement with whole-egg protein usually increased synthesis of trypsinogen and chymotrypsinogen but not amylase. Relatively more of the amino acid supply of the pancreas was diverted to chymotrypsinogen and less to amylase when whole-egg protein was fed. The reverse was true when casein was given. Rats fed the nitrogen-free diet synthesized relatively more trypsinogen. With respect to trypsinogen and chymotrypsinogen, the secretory response elicited by hydrolyzed casein and hydrolyzed egg protein was similar to the one evoked by casein. However, hydrolyzed egg protein was not equivalent to whole-egg protein. Interpretation of these results is based on the premise that dietary protein regulates pancreatic enzyme synthesis, in part, through amino acid pool(s) in the pancreas. The observation that the nitrogenfree diet retarded the rate of inactivation of amylase more than did the protein or hydrolyzed protein diets may be related to a protective effect of starch which was included in the nitrogen-free diet.