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Biomedical subjects

D H Baker

Publications and source records attributed to D H Baker.

At least 199 records · Page 11Linked to original sources
PubMed1984

Methionine peptides as potential food supplements: efficacy and susceptibility to Maillard browning.

Three experiments were conducted with young chicks fed purified diets to ascertain the bioefficacy of six different methionylmethionine (Met-Met) dipeptides, differing only in isomeric configuration, an oligopeptide (n = 8) of L-methionine, and also N-glycyl-L-methionine. DL/LD-Met-Met (50% D-Met-L-Met and 50% L-Met-D-Met), D-Met-L-Met, L-Met-D-Met, L-Met-L-Met, and N-Gly-L-Met were utilized as well as L-Met based on weight gain per millimole of sulfur consumed from each experimental compound. DD/LL-Met-Met (50% D-Met-D-Met and 50% L-Met-L-Met), D-Met-D-Met and L-oligo-Met were utilized less efficiently for chick growth. When the Met compounds were pretreated to facilitate Maillard browning (incubated at 37.6 degrees with dextrose at pH 9.5), all Met sources (except N-acetyl-L-Met, which was used as a positive control) exhibited reduced efficacy relative to an equivalent dietary addition of unreacted L-Met. The Met-Met peptides which when unreacted had been equivalent in efficacy to L-Met were, however, superior to L-Met when each compound, including L-Met, had undergone browning. N-Gly-L-Met was very reactive when heat-treated with dextrose, producing an almost black color after the 14-day incubation period, and its efficacy after browning was reduced by an even greater extent than was the case for L-Met.

Animals↗
PubMed1984

Urea cycle function in the dog with emphasis on the role of arginine.

English Pointer puppies were used in experiments designed to assess urea cycle function. A preliminary assay revealed a dietary arginine (Arg) requirement of 0.40% for maximal weight gain of puppies fed a chemically defined L-amino acid diet. Subsequent studies showed that consumption of an Arg-free diet resulted in growth failure, emetic episodes, mild hyperammonemia, decreased plasma Arg and urea, and orotic aciduria. Oral administration of ornithine (Orn), equimolar to 0.40% Arg, failed to correct these Arg deficiency symptoms. Consumption of an equimolar concentration of citrulline (Cit), on the other hand, resulted in near normal weight gains, but blood and urine metabolite levels still did not parallel those of dogs fed Arg. Plasma glucose concentration was unaffected by dietary treatment. Older dogs (20 weeks of age) performed no better than younger dogs (7 weeks of age) when fed an Arg-free diet. In a serial bleeding study, plasma ammonia increased after ingestion of an Arg-free diet, reached a peak during emesis and declined immediately thereafter. In contrast, plasma ammonia of dogs fed an Arg-adequate diet remained relatively constant. It was apparent that in terms of meaningful Arg replacement value, Orn had minimal activity. Cit could replace Arg for growth, but was not as efficient as Arg for urea cycle function.

Age Factors↗
PubMed1984

Selenium deficiency and transsulfuration in the chick.

Experiments were conducted to investigate the effect of selenium (Se) deficiency on the efficiency of cysteine formation from methionine (Met) in three strains of chickens. Hubbard, Leghorn, or crossbred (New Hampshire X Columbian) chicks were fed a crystalline amino acid diet that was fortified with both vitamin E and ethoxyquin but was essentially devoid of Se. The sulfur-containing amino acid (SAA) requirement was provided as equal quantities of Met and cystine (Cys-Cys) or as an isosulfurous level of Met alone. When fed diets unsupplemented with Se, all chicks exhibited depressed growth and markedly reduced blood glutathione peroxidase (SeGSH-Px) activities. SAA source had no effect on SeGSH-Px activity. Source of SAA also had no effect on growth rate of Leghorn or crossbred chicks, regardless of Se status. Se-deficient Hubbard chicks, on the other hand, gained faster and more efficiently when fed the Met-Cys-Cys combination than when fed an isosulfurous level of Met alone. Plasma concentrations of Cys-Cys and cystathionine were reduced in Se-deficient chicks of all strains. Homocystine was detected only in plasma of Hubbard chicks fed Se-adequate diets containing Met as the source of SAA. These findings support the view that transsulfuration efficiency may be impaired by Se deficiency in some strains of chickens.

Animals↗
PubMed1984

The iron-zinc interrelationship in the chick as influenced by Eimeria acervulina infection.

Two 14-day growth trials were performed to assess the effects of Eimeria acervulina infection (duodenal coccidiosis) on the Fe-Zn interrelationship in growing chicks. In the first assay, two levels of Fe (0 and 2000 mg/kg) were added to diets that contained either 0 or 52 mg supplemental Zn (from ZnCO3) per kilogram to establish whether excess Fe would affect Zn status of healthy and coccidial-infected chicks. In the second trial, either 0 or 2000 mg Zn/kg was added to diets containing 0 or 500 mg Fe/kg to determine whether Zn could modify Fe utilization. Based on chick performance as well as plasma Zn concentration, excess dietary Fe did not antagonize Zn in either healthy or E. acervulina-infected chicks. Coccidial infection, however, increased liver Fe and decreased intestinal Fe and hemoglobin concentration. Excess dietary Zn reduced performance and Fe content of tissues in both healthy and infected chicks. Coccidial infection ameliorated the adverse effects of excess Zn on performance and tissue Zn concentration and consequently enhanced Fe status of birds fed 2000 mg Zn/kg. These data suggest that the Fe-Zn interaction is a one-directional phenomenon in the chick, i.e., excess Zn reduces Fe utilization but excess Fe does not antagonize Zn.

Animals↗
PubMed1984

Complete cartilage-ring tracheal stenosis associated with anomalous left pulmonary artery: the ring-sling complex.

The persistent high mortality in infants with pulmonary artery "sling" (retrotracheal anomalous left pulmonary artery) is primarily due to the coexistence in such patients of long-segment tracheal stenosis due to complete cartilage rings. Five such patients are reported. Airway studies (by filtered high-kV radiography, bronchography, and/or CT) showed low carina, horizontal equal-length right and left mainstem bronchi, and long-segment tracheal stenosis. The length of the stenosis far exceeded the contact with the pulmonary sling. The suggested term "ring-sling complex" for such patients correctly places emphasis on detection of the tracheal malformation, which currently has no satisfactory surgical treatment.

Bronchography↗
PubMed1984

Effect of 3-nitro-4-hydroxyphenylarsonic acid on copper utilization by the pig, rat and chick.

Experiments were conducted to examine the effect of dietary roxarsone (3-nitro-4-hydroxyphenylarsonic acid) on Cu utilization by the pig, chick and rat. A fortified corn-soybean meal diet was fed in each experiment. Roxarsone dramatically reduced liver Cu concentration at all levels of supplemental Cu fed. The level of roxarsone commonly fed, 50 mg/kg diet, resulted in a two- to fourfold depression in liver Cu concentration in all species studied. The effects of roxarsone on weight gain were more perplexing. In the chick, the diets containing 100 and 250 mg Cu/kg depressed growth in the presence, but not in the absence, of 50 mg/kg dietary roxarsone. In contrast, at toxic levels of Cu, roxarsone had no effect on (500 or 750 mg Cu/kg diet) or slightly alleviated (1,000 mg Cu/kg diet) the growth-depressing effects of Cu. In the rat, a roxarsone level of 50 mg/kg diet exacerbated the growth-depressing effect of 1,000 mg Cu/kg diet. However, Cu had no effect on the growth depression that resulted from feeding a toxic level of roxarsone (250 mg/kg diet). The antagonizing effects of roxarsone and Cu on weight gain were not evident in the pig. Supplemental Cu (250 mg/kg diet) improved weight gain, but not feed efficiency, in starter pigs. Roxarsone (50 mg/kg diet) had no effect on the growth-promoting effects of Cu.

Animals↗
PubMed1984

Arsenic-sulfur amino acid interactions in the chick.

Experiments were conducted with growing crossbred chicks to determine the reasons why cysteine exacerbates roxarsone (3-nitro-4-hydroxyphenylarsonic acid) toxicity. A fortified corn-soybean meal diet that met or exceeded all nutrient requirements of the young chick was fed. While cysteine enhanced roxarsone toxicity, it had little effect on the toxicity of the inorganic arsenicals As2O3 and As2O5. The toxicity of another pentavalent organic arsenical, phenylarsonic acid, was also exacerbated by cysteine. In contrast, the growth-depression resulting from feeding the trivalent form of phenylarsonic acid, i.e., phenylarsine oxide, was not affected by dietary addition of cysteine. Supplementation of the diet with cystine, methionine or K2SO4 did not exacerbate roxarsone toxicity. Reduced glutathione (GSH), however, slightly increased the gain/feed depression resulting from feeding 300 mg roxarsone/kg diet. When injected ip 1) roxarsone and cysteine, or 2) roxarsone and ascorbic acid killed 100 or 60% of the birds, respectively, within 48 h postinjection. Few (6.7%) deaths resulted from ip injections of the same level of roxarsone alone. Therefore, the potentiation of toxicity requires pentavalent organic arsenicals and compounds that can act as reducing agents. We concluded that cysteine exacerbates roxarsone toxicity by reducing it to the more toxic trivalent state.

Amino Acids, Sulfur↗
PubMed1984

Feed additive interactions in the chicken: reduction of tissue copper deposition by dietary roxarsone in healthy and in Eimeria acervulina-infected or Eimeria tenella-infected chicks.

Interactions among roxarsone, copper, and coccidiosis were studied in growing crossbred chicks. Corn-soy or corn-soy-corn gluten meal diets were fed in all assays. In the absence of supplemental copper, 50 mg/kg roxarsone did not affect gain. However, in the presence of 250 mg/kg supplemental copper, there was a depression in gain due to feeding 50 mg/kg roxarsone. In contrast, at a toxic level of copper (1000 mg/kg), a growth response resulted from feeding roxarsone. In all instances, roxarsone markedly decreased liver copper concentration in birds fed high levels of copper. Multiple crop intubations of Eimeria acervulina or Eimeria tenella depressed performance and exacerbated copper toxicity symptoms. Copper supplementation as well as coccidial infection resulted in depressed plasma pigmentation.

Animals↗
PubMed1984

Lead toxicity in the chick as affected by excess copper and zinc and by Eimeria acervulina infection.

Several experiments were performed with young chicks to evaluate lead (Pb) toxicity and its effect upon copper (Cu) and zinc (Zn) toxicosis in the presence or absence of Eimeria acervulina infection. Toxic levels of Pb (3300 mg/kg) and Cu (500 mg/kg) or Zn (2000 and 4000 mg/kg) were added to completely adequate corn-soybean meal diets, while duodenal coccidiosis was produced by multiple crop inoculations of 4 X 10(5) sporulated E. acervulina oocysts. Both Pb and Cu depressed gain and feed efficiency while concomitant coccidial infection reduced these parameters further. Moreover, E. acervulina increased the concentration of liver Cu and kidney Pb. Although Pb supplementation slightly decreased the accumulation of liver Cu, additional Cu tended to increase the deposition of Pb in the kidney in both infected and uninfected birds. Similarly, chick performance was significantly reduced by excess dietary Pb or Zn, although coccidiosis slightly ameliorated the growth depression caused by toxic levels (4000 mg/kg) of Zn. Although 4000 ppm Zn and coccidial infection reduced the deposition of Pb in the kidney, this interaction was not evident when 2000 mg/kg Zn was fed to infected chicks. It is evident that Pb toxicosis in the chick is affected little by excess dietary levels of either Cu or Zn.

Animal Feed↗
PubMed1984

Eimeria acervulina infection and the zinc-cadmium interrelationship in the chick.

The purpose of this study was to evaluate the effects of Eimeria acervulina infection (duodenal coccidiosis) on cadmium (Cd) toxicity and zinc (Zn) status in the young chick. Additions of Cd (45 mg/kg) were made to diets that contained either 0 or 52 mg/kg supplemental Zn (from ZnCO3). Duodenal coccidiosis was produced by multiple crop inoculations of 4 X 10(5) sporulated E. acervulina oocysts. Growth and efficiency of feed utilization were reduced by dietary Cd addition while concurrent coccidial infection reduced these parameters further. Addition of Cd also increased Cd content of liver and kidney and depressed hemoglobin, hematocrit, and plasma Zn content. Coccidial infection exacerbated tissue Cd deposition and depressed hematological parameters further. Although dietary Zn addition ameliorated some of the adverse effects of Cd toxicity, Cd administration tended to enhance tissue Zn deposition. Administration of Cd enhanced synthesis of metallothionein.

Animals↗
PubMed1984

Zinc utilization in the chick as influenced by dietary concentrations of calcium and phytate and by Eimeria acervulina infection.

Experiments were performed to investigate the effects of Eimeria acervulina infection (duodenal coccidiosis) on the zinc (Zn)-calcium (Ca)-phytate interrelationship in the chick. Three supplemental levels of Ca (0, .91, and 1.82%), two of Zn (0 or 52 mg/kg), and two of sodium phytate (0 or 1.2%) were evaluated as to their effects when added to completely adequate corn-soybean meal diets. Duodenal coccidiosis was produced by multiple crop inoculations of 4 X 10(5) sporulated E. acervulina oocysts. Calcium supplementation depressed gain and efficiency of feed utilization, while Zn content of tissue and plasma was also lowered. Coccidial infection tended to reduce these values further. The addition of dietary phytate also depressed performance and deposition of Zn in tissue. Both excess dietary Ca and phytate addition to the diet markedly reduced plasma Zn concentration of birds fed corn-soybean meal diets unsupplemented with Zn. Addition of 52 mg/kg Zn, however, prevented excess Ca or phytate from exerting this effect. Parasitized chicks responded markedly with increased gain and gain/feed ratios when 52 mg/kg supplemental Zn was added to a 24% protein corn-soybean meal diet containing 1.82% total dietary Ca. It is evident, therefore, that the Zn-antagonizing effect of excess Ca (in the presence of phytate) is exacerbated by duodenal coccidiosis.

Animals↗
PubMed1984

Influence of dietary electrolyte balance, energy, and amino acid supplementation on the monensin response in chicks fed diets varying in protein content.

The effects of several dietary factors on the anorexigenic response to monensin in chicks fed corn-soybean meal diets varying in crude protein (CP) were investigated. In Trial 1, crossbred chicks (New Hampshire X Columbia) were fed a 16% CP diet with or without 160 mg/kg monensin and/or .53% potassium carbonate in a 2 X 2 factorial design. Monensin supplementation caused a 24.5% growth depression, and potassium carbonate had no effect on the monensin-induced depression. Trials 2 and 3 were designed to evaluate the effects of dietary energy level on the monensin response in commercial broiler chicks fed diets containing 24, 20, or 16% CP. As CP level was decreased, the depression in performance from 121 mg/kg monensin increased. Increasing the energy concentration of the 24 and 20% CP diets to that of the 16% CP diet had no consistent effect on the response of chicks to monensin. Trial 4 was conducted to determine the influence of amino acid (AA) supplementation on the monensin response in broiler chicks fed a low-protein diet. Supplementation of a 16% CP diet with an AA mixture (3% glutamic acid plus essential AA equal to the 24% CP diet) improved growth performance markedly. Deletion of methionine, arginine, and lysine from the AA mixture yielded performance well below that of chicks fed the unsupplemented 16% CP diet, indicating a severe AA imbalance. Monensin supplementation at 121 mg/kg caused a much greater growth depression in chicks fed 16% CP or 16% CP plus the complete AA mixture than in those fed 24% CP or the AA-imbalanced 16% protein diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1983

Eimeria acervulina infection in chicks fed deficient or excess levels of manganese.

Four experiments were conducted with young chicks to investigate the effect of duodenal coccidiosis caused by Eimeria acervulina infection on Mn toxicity or deficiency. Coccidiosis depressed gain and efficiency of feed utilization. Weight gain was depressed by 3000 mg/kg Mn, but not by 1500 mg/kg. Coccidiosis exacerbated Mn toxicity as assessed by hematological parameters; it also dramatically increased bone and bile Mn concentrations in chicks fed high levels of Mn. The increase in Mn absorption caused by coccidiosis resulted in a lower dietary requirement for Mn. In fact, the coccidial infection almost doubled the rate of Mn uptake by bone.

Absorption↗
PubMed1983

Zinc toxicity, zinc deficiency and zinc-copper interrelationship in Eimeria acervulina-infected chicks.

Three experiments were conducted with young chicks to investigate the effect of duodenal coccidiosis caused by Eimeria acervulina infection on Zn toxicity, Zn deficiency and the interrelationship between Zn and Cu. The coccidial infection depressed both rate and efficiency of weight gain. Dietary Zn addition at 2000 mg/kg depressed performance only slightly, but the 4000 mg/kg reduced both gain and gain/feed markedly. The coccidial infection appeared to have an ameliorative effect on Zn toxicity as assessed by performance and by hematological parameters. Excess Zn (2000 and 4000 mg/kg) dramatically increased liver, pancreas and bone Zn levels. The coccidial infection, however, decreased tissue Zn levels. Copper toxicity caused by feeding 500 mg Cu per kilogram diet was exacerbated by E. acervulina infection. A Zn-Cu antagonism was observed in both control and in coccidiosis-infected chicks. Excess dietary Zn decreased tissue Cu deposition, but excess Cu did not affect tissue Zn deposition. Copper partially ameliorated Zn toxicity symptoms. The efficacy of Cu in overcoming the Zn-induced depressed hematological parameters, however, was enhanced slightly by coccidiosis. E. acervulina infection did not affect the chick's Zn requirement. Growth data were more reliable as indicators of the Zn requirement than were blood or bone parameters.

Animals↗
PubMed1983

Effect of excess dietary lysine on plasma lipids of the chick.

Feeding diets with 4% L-lysine to the chick produces an elevation of plasma lipids which does not occur when feeding an excess of any other amino acid. Experiments were conducted to determine whether lysine-induced hyperlipidemia is secondary to the antagonistic effect of lysine on arginine or to the anorexia which accompanies lysine feeding, and in addition, whether the lysine-induced hypercholesterolemia is affected by chick age. In all experiments gain and food intake were reduced by feeding chicks 4% lysine. Plasma cholesterol and triglyceride were elevated, but high-density-lipoprotein cholesterol, as a percentage of total, was reduced. Addition of dietary arginine up to 4% failed to reverse the depression in performance and elevation of plasma lipids. Pair-feeding the control diet to the amount consumed by lysine-fed chicks did not elevate plasma lipids above control levels. Thus, lysine-induced hyperlipidemia is not mediated by the antagonistic effect of lysine on arginine nor by the effect of lysine on food intake. The high-lysine diet prevented the normal decline in plasma cholesterol expected with advancing age of chicks. Preliminary results suggested that excess lysine stimulated cholesterol biosynthesis.

Animals↗
PubMed1983

Childhood typhlitis: its increasing association with acute myelogenous leukemia. Report of five cases.

Five children with acute myelogenous leukemia (AML) are described in whom typhlitis developed early in the course of the disease. The plain and barium-enema radiographic findings of mass effect and bowel edema ("thumbprinting") were similar among the cases, although nonspecific. The increasing association of typhlitis with AML and its earlier appearance in the course of the disease should be recognized.

Adolescent↗
PubMed1983

Arginine requirement of the young pig.

Four experiments were conducted with an arginine (Arg)-deficient, semipurified diet to determine the Arg requirement of the weanling pig. The semipurified diet contained .18% bioavailable Arg as determined by a chick bioassay procedure and, when properly supplemented with Arg, allowed rat growth equal to that obtained with a 19.2% protein corn-soybean meal diet. A preliminary experiment with pigs indicated that the semi-purified diet was markedly deficient in Arg. The Arg requirement of the pig was estimated by adding L-Arg to the semipurified diet such that final dietary Arg levels were .18, .23, .28, .38 and .48% (Exp. 2 and 3) or .48, .58 and .68% (Exp. 4). Weight gain and efficiency of feed utilization were maximized at .48% dietary Arg. Plasma urea-N was increased and plasma NH3-N decreased by .48% Arg compared with lower levels. A slight orotic aciduria was observed in pigs fed Arg levels below .48%. From these results, it is concluded that the Arg requirement of the weanling pig is .48% of the diet, a level twice the current NRC estimate.

Amino Acids↗