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Biomedical subjects

D H Baker

Publications and source records attributed to D H Baker.

At least 217 records · Page 12Linked to original sources
PubMed1983

Blood and liver concentrations of glutathione, and plasma concentrations of sulfur-containing amino acids in chicks fed deficient, adequate, or excess levels of dietary cysteine.

Experiments were conducted with young male chicks to examine the influence of cysteine status on blood and liver glutathione (GSH) concentrations and plasma sulfur amino acids. The equivalence of cystine, cysteine, and GSH as sources of dietary cysteine for the chick was reconfirmed. Whole-blood GSH was unresponsive to dietary cysteine level, but liver GSH increased as dietary cysteine increased from a deficient level to the required level. Excess levels of cysteine (two or four times the chick's requirement) elicited no further increase in hepatic GSH. Plasma cystine concentration increased markedly (i.e., ninefold) and in a linear fashion while plasma cysteine increased only modestly (i.e., twofold) as dietary cysteine level increased.

Amino Acids, Sulfur↗
PubMed1983

The choline-methionine interrelationship for growth of the chick.

Three experiments involving 1230 battery-reared crossbred chicks were conducted to evaluate the potential sparing effect of choline on methionine and vice versa. Experiment 1 employed a crystalline amino acid diet to establish the sulfur-amino acid (SAA) and choline requirement for maximal feed efficiency of chicks during the period 8 to 18 days posthatching. Six graded levels of DL-methionine (.20 to .45% in the presence of .20% L-cystine) and five of choline (0 to 1216 mg/kg) were employed in a 6 X 5 factorial treatment arrangement. Gain/feed ratio was maximized at 608 mg/kg choline at all levels of methionine and at .30 to .35% methionine at all levels of choline. Two identical experiments (8 to 25 days posthatching) with a corn-soybean meal diet were carried out to explore the relationship between supplemental methionine (0 to .20% in five equal increments) and supplemental choline (0, 217, and 434 mg/kg). Optimal performance occurred at .10% supplemental methionine regardless of choline level and at 217 mg/kg choline at supplemental methionine levels of 0 and .05%. At .10, .15, and .20% supplemental methionine, no gain or gain/feed response to supplemental choline was observed. It was thus apparent that excess levels of choline had minimal capacity to reduce the dietary requirement for methionine. Excess levels of methionine, however, seemed to have a consistent, although small, effect on the chick's dietary need for choline.

Animals↗
PubMed1983

Precursor (amino acid): product (vitamin) interrelationship for growing chicks as illustrated by tryptophan-niacin and methionine-choline.

Experiments were conducted with crossbred chicks to examine the growth response to a vitamin when its precursor amino acid was in either deficient or adequate supply in the diet and vice versa. The tryptophan-niacin and methionine-choline interrelationships were thus examined. No growth responses to dietary niacin or choline were observed during severe tryptophan or methionine deficiency, respectively. However, when adequate levels of the precursor amino acids were present, marked gain and gain/feed responses to these vitamins occurred. In contrast, gain and feed efficiency responses to tryptophan or methionine occurred regardless of the chick's niacin or choline status, respectively.

Animals↗
PubMed1983

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

An experiment was conducted with young chicks to investigate the effect of duodenal coccidiosis caused by Eimeria acervulina infection on the interrelationship between dietary copper (Cu) and zinc (Zn). A corn-soybean meal diet (devoid of Zn fortification) was supplemented with Zn (50 mg/kg) or Cu (250 mg/kg), or both; these diets were fed to control or coccidiosis-infected chicks. The coccidial infection depressed rate and efficiency of weight gain. Excess dietary Cu had no effect on performance of control or infected chicks. Zinc supplementation did not affect performance of control chicks, but it improved both rate and efficiency of weight gain in E. acervulina-infected chicks. Liver Zn concentration was decreased by coccidiosis, increased by Zn supplementation, but unaffected by excess dietary Cu. Liver Cu concentration was increased by excess dietary Cu and by coccidiosis but decreased by Zn supplementation of the diet. These data indicate that coccidiosis impaired Zn utilization and precipitated Zn deficiency in the chick.

Animals↗
PubMed1983

Effect of dietary protein source and monensin on performance of chicks.

The effects of dietary protein source and monensin on growth performance of chicks fed diets containing 121 or 160 mg/kg monensin were investigated. Crossbred chicks (New Hampshire X Columbian) were fed a corn soybean meal diet (24% crude protein) containing 0, 5.0, or 13.0% animal-source protein supplied by various combinations of fish meal and meat and bone meal. Growth rate and gain/feed ratio were measured from 8 to 22 days posthatching. Growth performance was depressed by both 121 and 160 mg/kg monensin with the depression being greater at 160 mg/kg. The type or level of animal-source protein had no effect on the magnitude of growth depression caused by monensin. Growth performance was improved by addition of fish meal and meat and bone meal to the corn-soybean meal diet.

Animals↗
PubMed1983

Excess manganese ingestion in the chick.

Two experiments were conducted with young chicks to investigate effects of excess manganese, (Mn) ingestion and to compare MnCl2 . 4H2O, MnSO4 . H2O, MnO2, and MnCO3 as sources of dietary Mn activity. Each source of Mn was added to a conventional corn-soybean meal diet to supply 3000, 4000, or 5000 mg/kg Mn. High levels of dietary Mn from MnSO4 . H2O and MnCl2 . 4H2O depressed growth slightly; MnO2 and MnCO3 did not affect chick performance. Manganese dioxide contained less Mn activity than MnCO3, MnSO4 . H2O, or MnCl2 . 4H2O as assessed by relative depressions in hemoglobin and hematocrit and by relative increases in bile, liver, and bone Mn concentrations. Neutralization of the chloride ion in MnCl2 . 4H2O with NaHCO3 did not ameliorate the adverse effects of excess, MnCl2 . 4H2O ingestion. Bone and bile Mn concentrations reflected Mn intake better than liver Mn concentration or rate and efficiency of weight gain.

Animals↗
PubMed1983

Protein-amino nutrition of nonruminant animals with emphasis on the pig: past, present and future.

During the period of 1958 to 1983, the fortified corn-soybean meal diet became standard for swine production systems. Dietary formulation changed from a protein to an amino acid basis. Amino acid requirements were established for all classes of swine. For growing swine, some of these studies led to refinements of earlier estimated requirement values, but for brood sows, both gestating and lactating, requirements for virtually all of the indispensable amino acids were established for the first time. With requirement values available, attention turned to factors affecting requirements, e.g., protein level, energy level, amino acid balance, sex and criterion of response. In addition, initial attempts were made to obtain amino acid bioavailability values for swine feedstuffs. Other nonruminant species were also represented in the dramatic changes that occurred in protein-amino acid nutrition. Improved and highly palatable purified crystalline amino acid diets were developed for rats, chicks, dogs, cats, rabbits and fish. Nitrogen nutrition and metabolism of nonruminant herbivores (e.g., rabbits and horses) likewise became better understood during the last 25 yr.

Amino Acids↗
PubMed1982

The ureteral "J" sign: radiographic demonstration of iatrogenic distal ureteral obstruction after ureteral reimplantation.

Progressive caliceal and ureteral dilatation in postoperative patients is assumed to be secondary to either postoperative distal ureteral stricture or ureteral atony. Any study used to differentiate obstruction from atony must be done with an awareness of the effect of a full bladder on the upper tracts, since it can by itself produce varying degrees of ureteral dilatation. We describe 2 patients who had virtually complete distal ureteral obstruction on anterograde pyelography with a "J" shaped distal ureteral segment. The striking observation was that the deformity and associated distal ureteral obstruction could be made to appear and disappear at will, merely by distending or emptying the bladder. We believe that this is an important factor in the progressive dilatation, as well as in the observed deterioration of renal function, and it is properly regarded as an iatrogenic complication.

Child↗
PubMed1982

Comparative utilization of the alpha-keto and D- and L-alpha-hydroxy analogs of leucine, isoleucine and valine by chicks and rats.

Several experiments were conducted to quantitatively evaluate the growth-promoting capacity of the isomers of the branched-chain amino acids (BCAA) and their alpha-hydroxy and alpha-keto analogs for the chick and rat. Basal chemically defined diets were formulated to be singly deficient in the BCAA under study; analogs therefore were evaluated as sources of supplemental amino acid activity. DL-Isoleucine (DL-Ile), alpha-keto-beta-L-methylvaleric acid (KMV) and the isomers of alpha-hydroxy-beta-methylvaleric acid (HMV) were inferior to an isomolar level of L-Ile and varied considerably in their capacity to support growth of chicks and rats. Efficacy values of the compounds for chicks (C) and rats (R) were: DL-Ile 85% (C), 58% (R); KMV 60% (C), 38% (R); L-HMV 84% (C), 65% (R); DL-HMV 49% (C), 45% (R); and D-HMV -10% (C), -2% (R). The isomers of valine (Val) and alpha-hydroxyisovaleric acid (HIV) had efficacy values in chicks of: DL-Val, 84%; D-Val, 72%; L-HIV, 82%; DL-HIV, 79%; D-HIV, 66%. D-Val had only marginal growth-promoting activity for rats, 16%. All Val analogs had comparable efficacy values for the rat: alpha-ketoisovaleric acid (KIV), 49%; L-HIV, 54%; DL-HIV, 51%; and D-HIV, 46%. DL-Leu and D-Leu, alpha-ketoisocaproic acid (KIC), and L-, DL- and D-alpha-hydroxyisocaproic acid (HIC) were all less efficacious than isomolar amounts of supplemental L-Leu in rats. Efficacy values were: DL-Leu, 78%; D-Leu, 48%; KIC, 56%; L-HIC, 58%; DL-HIC, 55%; and D-HIC, 41%. The BCAA keto analogs were not superior to the L-alpha-hydroxy analogs in growth-promoting capacity, and this is of great interest for the potential use of these nitrogen-free amino acid analogs in nutritional therapy.

Animals↗
PubMed1982

Iron status of the chick as affected by Eimeria acervulina infection and by variable iron ingestion.

Several experiments were conducted with crossbred chicks to investigate the effect of duodenal coccidiosis caused by Eimeria acervulina infection on iron status of chicks fed iron levels ranging from deficient to excess. Coccidiosis depressed weight gain and efficiency of feed utilization at all dietary levels of iron. Excess supplemental iron (500-1500 mg/kg) did not affect performance of uninfected chicks, but 1500 mg/kg iron exacerbated the coccidiosis-induced growth depression. In the presence of coccidiosis, 1000 and 1500 mg/kg iron significantly increased liver iron concentrations over that found in uninfected chicks fed the same levels of iron. Dietary iron increased intestinal iron content, but the increase was partially ameliorated by the coccidial infection. Plasma iron and total iron-binding capacity (TIBC) were decreased by acute coccidiosis (6 days postinoculation); however, by day 14 the coccidial infection was without effect on plasma iron, while TIBC tended to be elevated. Coccidiosis increased the chick's dietary iron requirement, but only because of decreased feed intake. Performance and hematological parameters were maximized approximately 0.9 mg iron per day in both control and infected chicks.

Animals↗
PubMed1982

Comparative utilization of the isomers of phenylalanine and phenyllactic acid by chicks and rats.

A series of experiments was conducted to assess quantitatively the growth-promoting capacity of the isomers of phenylalanine (Phe) and phenyllactic acid (PLA). The slope-ratio procedure was used to determine percent efficacy relative to l-Phe. Addition of the isomers of Phe to a Phe-deficient chemically-defined diet produced linear growth and feed efficiency responses. Only the l-isomer and racemic mixture of PLA elicited a gain or gain:feed response. Efficacy estimates for male chicks were: dl-Phe, 90.1%; d-Phe, 74.6%; l-PLA, 70.1%; dl-PLA, 5.9%. The comparative utilization of d-Phe, phenypyruvic acid (PPA) and l-PLA by chicks was also evaluated when these compounds were fed to male chicks as the sole source of dietary Phe. PPA activity, 84.8%, was slightly greater than that of either d-Phe, 75.3%, or l-PLA, 67.4%. Efficacies of l-PLA and dl-PLA were 46.1 and 28.0%, respectively, d-PLA had no growth-promoting activity for the rat.

Animals↗
PubMed1982

Efficacy of methionine peptides as determined by chick bioassay.

Chick growth assays were used to evaluate the efficacy of poly-L-methionine and DL/LD methionylmethionine ( a 50:50 mixture of D-Met-L-Met and L-Met-D-Met). The polypeptide possessed no bioefficacy whatever, probably due to its extreme insolubility. The dipeptide of methionine exhibited growth-promoting ability equal to that of DL-methionine itself.

Animals↗
PubMed1982

Eimeria acervulina infection in chicks fed cobalt in the presence or absence of excess dietary methionine.

An experiment was conducted with young, male, crossbred chicks to investigate the interaction between dietary cobalt, methionine and experimental Eimeria acervulina infection (duodenal coccidiosis). Coccidiosis and dietary cobalt (250 mg/kg) depressed weight gain and efficiency of feed utilization; cobalt toxicity, however, was exacerbated by the coccidial infection, resulting in a depression in performance greater than could be accounted for by the independent additive effect of each entity. Dietary cobalt increased the cobalt concentration of the liver, kidney and gallbladder (with bile); experimental coccidiosis in the absence of excess dietary methionine resulted in a twofold increase in cobalt deposition in the liver and gallbladder. Excess supplemental methionine partially alleviated the decrease in chick performance and the increase in tissue cobalt content caused by dietary cobalt in both healthy and infected chicks, but with a slightly greater efficacy in the coccidiosis-infected chicks.

Animals↗
PubMed1982

Tolerance of the chick to excess dietary cadmium as influenced by dietary cysteine and by experimental infection with Eimeria acervulina.

Three experiments were conducted with 9-d-old crossbred chicks to determine the effect of supplemental L-cysteine.HCl.H2O on tolerance to excess dietary Cd. Cd levels of 30 or 60 mg/kg added to a fully fortified corn-soybean meal diet depressed both body weight gain and gain:feed ratio and increased kidney Cd concentration. Supplemental cysteine (i.e., .59% L-cysteine.HCl.H2O) did not alleviate the depression of weight gain or gain:feed ratio due to Cd feeding but did decrease kidney Cd accumulation. Eimeria acervulina infection (i.e., duodenal coccidiosis) depressed rate and efficiency of weight gain and resulted in increased Cd concentrations in kidney tissue. Cystein supplementation increased kidney cadmium concentration even further in E. acervulina-infected birds.

Animal Feed↗
PubMed1982

Eimeria acervulina infection in chicks fed excess copper in the presence or absence of excess dietary methionine.

Five experiments were conducted with young, male, crossbred chicks to investigate the effects of experimental Eimeria acervulina infection on the efficacy of supplemental Cu and (or) methionine when added to a corn-soybean meal diet. Duodenal coccidiosis (due to E. acervulina) and supplemental Cu (500 and 750 mg/kg) depressed weight gain and efficiency of feed utilization. Supplemental Cu increased concentrations of Cu in liver and gallbladder; experimental coccidiosis resulted in a two- to fourfold increase in Cu deposition in these tissues compared with the respective controls. Excess supplemental methionine (.5%) had little effect on Cu toxicity in either healthy or infected chicks. Monensin, an ionophorous coccidiostat, alleviated the coccidiosis-induced Cu deposition.

Animal Feed↗
PubMed1982

Performance and concentration of amino acids in plasma and urine of young pigs fed diets with excesses of either arginine or lysine.

Four experiments were conducted to investigate the arginine x lysine interaction in young pigs. Excess supplemental arginine (.67 to 2% of diet) decreased weight gain and feed intake, but had no effect on efficiency of feed utilization. Lysine supplementation (.5 or 2.5%) did not ameliorate the adverse effects of excess arginine. Decreasing the arginine content to .8% from a level routinely supplied by typical swine diets (1.3%) did not improve pig performance. Excess supplemental arginine increased plasma arginine and ornithine concentrations and decreased plasma lysine and histidine concentrations; several other amino acids were decreased in plasma as well. Feeding 2.8% total dietary arginine resulted in a dramatic increase in urinary excretion of arginine, ornithine, citrulline, lysine, histidine and cystine. From these results it is concluded that the adverse effects of excess arginine represent classic amino acid imbalance rather than amino acid antagonism.

Amino Acids↗
PubMed1982

Utilization of D- and L-tryptophan by the growing dog.

Two 4 x 4 Latin square experiments were conducted with English Pointer puppies to determine the growth promoting capacity of D-tryptophan (trp) relative to L-trp and to estimate the trp requirement of the growing dog. Based upon a multiple linear regression slope-ratio technique, D-trp had an efficacy value of 35.5 +/- 6.4% relative to L-trp. The urine of dogs fed D-trp contained 14.6% of the ingested trp; no measurable trp was recovered in the urine of dogs fed L-trp. The trp requirement for maximal weight gain was at least .16% for 6-to 10-wk-old dogs, between .12 and .16% for 10- to 12-wk-old dogs and less than or equal to .12% for 12- to 14-wk-old dogs. The overall requirement for the 6- to 14-wk age period was .15%. Total N, as well as urea-N, in urine decreased and N retention increased with increasing levels of dietary L-trp; NH3-N, creatinine-N and fecal-N were unaffected by treatment.

Amino Acids↗