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Biomedical subjects

D H Baker

Publications and source records attributed to D H Baker.

At least 253 records · Page 14Linked to original sources
PubMed1980

Lysine and protein levels in corn-soybean meal diets for growing-finishing swine.

Previous work with growing swine indicated that the lysine requirement, expressed as a percentage of the diet, decreased by .02 percentage units with each 1% reduction in dietary protein level. Thus, the dietary lysine needed for optimal performance may be less than the reported requirement when a portion of the soybean meal in a corn-soybean meal diet is replaced with crystalline lysine. An experiment was conducted to test this concept in each of three phases of growth: growing (23.6 to 47.2 kg), early finishing (47.2 to 74.8 kg) and late finishing (74.8 to 92.8 kg). Dietary crude protein levels were 16, 13 and 12% for the positive control regimen and 14, 11.5 and 11% for the negative control regimen during the growing, early finishing and late finishing periods, respectively. In each phase of growth, regimen 1 was the positive control; regimen 2 was the negative control plus lysine to the level in the positive control; regimen 3 was the negative control plus lysine to the level in the positive control less .02% lysine for each 1% decrease in crude protein from the positive control level; and regimen 4 was the negative control. Ninety-six crossbred pigs were used to form two barrow and two gilts replicates with six pigs per pen-replicate. Average daily gains summarized over the entire growing-finishing period were .74, .75, .75 and .65 kg per day for regimens 1, 2, 3 and 4, respectively. Corresponding gain to feed ratios were .29, .29, .30 and .26. Within each growth phase, average daily gain and gain to feed ratio followed patterns similar to the overall results. Carcass evaluation of barrows indicated a trend toward leaner carcasses from pigs on regimens 1, 2 and 3 than from those on regimen 4. Thus, the lysine requirement can be reduced when crude protein levels are reduced by replacing soybean meal with synthetic lysine.

Animal Nutritional Physiological Phenomena↗
PubMed1980

Histidine, phenylalanine-tyrosine and tryptophan requirements for growth of the young kitten.

Growth assays were conducted to estimate the minimal dietary requirement levels of histidine, tryptophan, phenylalanine and tyrosine for the young kitten. Dietary concentrations of histidine and tryptophan of .30 and .15%, respectively, were found to support optimal kitten performance. A preliminary study of the total aromatic amino acid (TAAA) requirement indicated that no more than 1.20% TAAA (.60% phenylalanine + .60% tyrosine) is required by the kitten. Subsequent experiments revealed no decrease in growth rate when TAAA were reduced to 1.00% of the diet. At this level of TAAA, tyrosine could supply 50% of the requirement for TAAA.

Animals↗
PubMed1980

Effect of high-level copper feeding on the sulfur amino acid need of chicks fed corn-soybean meal and purified crystalline amino acid diets.

Supplementation of a corn-soybean meal diet with .05% methionine maximized gain and feed efficiency of three-week-old chicks fed copper at either 0 or 250 mg/kg. With copper present at 500 mg/kg, the supplemental methionine requirement was in excess of .10%. Liver copper stores of chicks fed copper at 250 mg/kg declined linearly as supplemental methionine level increased, but methionine level had no effect on liver copper when chicks were fed 500 mg/kg copper. Liver copper accumulation did not occur in chicks fed 250 mg/kg copper when supplemental sulfur was provided as a combination of .05% methionine and 1800 mg/kg sulfide. Irrespective of methionine level, sulfide addition reduced liver copper by one-half in birds fed 500 mg/kg copper. Chicks fed the purified diet were appreciably more susceptible to copper toxicity than those fed the corn-soybean meal diet. Chicks fed the purified diet without supplemental copper required .52% sulfur amino acids (SAA). Chicks fed copper at 250 and 500 mg/kg required .65 and .70 SAA, respectively, although gain and feed efficiency were still depressed when compared with the performance of the control birds. Higher levels of methionine failed to restore growth rates to those achieved with birds fed no supplemental copper. Supplementing the copper-containing diets with up to 1.6% cystine improved performance some but failed to completely overcome the growth depressing effect of copper at 500 mg/kg. Results of additional studies indicated that the purified diet containing .70% SAA and 500 mg/kg copper was nutritionally adequate and that the marked toxicity of copper when fed in the purified diet was due to the chemical nature of the diet rather than to any specific copper-induced nutritional deficiencies.

Amino Acids↗
PubMed1980

Lasalocid-sulfur amino acid interrelationship in the chick.

Several experiments were conducted with young healthy chicks to investigate the relationship between lasalocid and sulfur-containing amino acids (SAA). Chicks were housed in heated starter batteries in all experiments and were fed, in all but one trial, a completely purified crystalline amino acid diet. As previously determined in our laboratory with monensin, the quantitative requirement for SAA, expressed as a percent of the diet, was neither increased not decreased by 125 mg/kg dietary lasalocid. Unlike that observed with monensin, a consistent and striking SAA X lasalocid interaction was apparent. Hence, lasalocid elicited a marked gain and gain/feed response when added to diets severely deficient in SAA, but it resulted in a marked depression in chick performance when added to diets adequate in SAA. At moderate levels of SAA deficiency, such as those existing in practical corn-soybean meal broiler diets, 125 mg/kg lasalocid neither increased nor decreased rate and efficiency of weight gain. Indeed, no evidence of the SAA X lasalocid interaction was seen when lasalocid was provided in a typical corn-soybean meal chick starter diet.

Amino Acids, Sulfur↗
PubMed1980

Nitrogen requirement of the kitten.

Three experiments were conducted to determine the nitrogen (N) requirement of the young kitten. The feline basal diet contained minimal requirement levels of each indispensable amino acid (IAA) to comprise a total dietary N concentration of 2.52% and an IAA N to dispensable amino acid (DAA) N ratio (I/D) of 0.70. In experiments 1 and 2, both the dietary N concentration and I/D ratio were varied through changes in either the DAA level (experiment 1) or IAA level (experiment 2). The results revealed that a reduction in either dietary N or in I/D ratio from basal levels (ie, 2.52% N and I/D ratio of 0.70) depressed (P less than 0.05) kitten weight gain, feed efficiency, and N retention, whereas simultaneous increases in each resulted in no further improvement in these responses. Comparison of this feline basal diet with a commercial ration (experiment 3) revealed no differences (P less than 0.10) in gain, gain/feed, or N retention, although the purified diet showed superiority (P less than 0.01) when gain/N intake was determined (13.3 vs 5.7). Therefore, the feline dietary N requirement has been estimated to be 2.52% (15.75% protein equivalent) or 16% of the calories as protein. In the process of these experiments, creatinine and orotic acid excretion from kittens fed the purified diet were constant, averaging (+/- SEM) 24.7 +/- 0.7 mg/kg of body weight and 9.95 +/- 2.3 micrograms/mg of creatinine, respectively. Urea-N and ammonia-N comprised approximately 83.0% and 3.8% of the total urinary nitrogen.

Animal Nutritional Physiological Phenomena↗
PubMed1979

Estimation of nutrient requirements from growth data.

Two least squares methods of estimating nutrient requirements from growth data were compared. One method involved fitting a broken line by the method of least squares. The requirement was taken as the abscissa of the breakpoint in the curve. The other method involved fitting an appropriate exponential function to the growth data and estimating the requirement as the abscissa of the point on the fitted curve whose ordinate was 95% of the upper asymptote. For the nine sets of data studied, the broken line provided adequate fits for only six. The nonlinear models provided adequate fits for all the data studied. When both the broken line and the chosen nonlinear model provided adequate fits, the estimated requirements were nearly the same. However, the consistently good fits obtained with the nonlinear models suggest that this approach may generally be more useful.

Amino Acids↗
PubMed1979

Efficacy of the D- and L-isomers of N-acetylmethionine for chicks fed diets containing either crystalline amino acids or intact protein.

Chick growth assays were used to evaluate the efficacy and toxicity of the L- and D-isomers of N-acetylmethionine when fed as a source of methionine in crystalline amino acid diets. In agreement with earlier rat studies employing intact protein diets, N-acetyl-L-methionine had a methionine-sparing value of 100% and N-acetyl-D-methionine a value of zero. The former was also observed to be fully effective as a methionine supplement when added to a methionine-deficient diet containing equal protein contributions from soybean, casein and gelatin. Isosulfurous levels of excess L-methionine or N-acetyl-L-methionine were equally growth depressing, but L-methionine elevated spleen iron deposition to a greater extent than N-acetyl-L-methionine. N-acetyl-D-methionine in excess depressed growth only slightly, due entirely to a depression in voluntary food intake, and no evidence of splenic hemosiderosis was observed from this addition.

Amino Acids↗
PubMed1979

Lysine and arginine requirements of the domestic cat.

Domestic kittens were used in four experiments to establish quantitative requirements for lysine and arginine. A purified L-amino acid diet (by calculation, 4,700 kcal metabolizable energy/kg diet) was employed throughout. Weight gain, gain:feed and nitrogen retention data of cats fed dietary lysine levels ranging from 0.48 to 1.92% suggested a requirement not exceeding 0.80%. The dietary arginine requirement for maximal gain was assayed at this level of lysine and found to be not greater than 0.83%. A dietary arginine level of 0.33% resulted in vomiting and extreme lethargy within 4 hours of ingestion.

Ammonia↗
PubMed1978

Thymic uptake of gallium-67 citrate in a healthy 4 year old boy.

Gallium uptake in a mediastinal mass has been most often seen with lymphoma. A case is reported of thymic uptake in an otherwise healthy 4 1/2 year old boy who had recently had pneumonia. Serial films always showed an unchanging prominent though normal thymus and follow up gallium scans showed disappearance of thymic uptake. This and other similar cases indicate the need to consider a non-neoplastic thymus when gallium accumulation is noted in the anterior mediastinum of a child.

Child, Preschool↗
PubMed1978

Improved plainfilm diagnosis of right aortic arch anomalies with high kilovoltage-selective filtration-magnification technique.

In the pediatric patient, the presence of a right aortic arch is an important roentgen observation. It may be associated with vascular rings and cyanotic heart disease and may complicate the repair of tracheoesophageal fistula. It may be missed on conventional low KVP radiographs but is easily detected on high kilovoltage-filtered films with air gap magnification.

Airway Obstruction↗
PubMed1978

Calcific thrombi of the inferior vena cava in infants and children.

Calcified caval thrombus should be considered in any infant or child where calcifications are noted in the high right retroperitoneal area on plain x-rays of the abdomen. Although typically bullet-shaped in configuration, the calcium distribution in the neonate may be atypical or incompletely developed, suggesting neuroblastoma. Definitive diagnosis can be made by inferior vena cavagram. As no deaths or complications have been attributed to the lesion in the cases thus far reported, no specific treatment is recommended.

Abnormalities, Multiple↗
PubMed1978

Factors affecting methionine toxicity and its alleviation in the chick.

Young male crossbred chicks were fed crystalline amino acid diets containing excess L-methionine or DL-homocysteine to evaluate factors causing methionine toxicity. Chicks were fed diets containing graded levels of excess methionine from 0% to 2.0%. Rate of gain was reduced at all levels of excess methionine, but the magnitude of depression was greater between 1% and 2% than between 0% and 1% excess methionine. Methionine accumulated in plasma of birds fed excess methionine, but plasma levels of homocysteine, cystathionine and cystine remained essentially unchanged. Spleen iron levels increased linearly and blood hemoglobin decreased linearly when chicks were fed diets containing greater than 1% excess methionine, a level equivalent to about 3 times the chicks' requirement. Chicks fed 1.36% homocysteine had reduced gain and gain:feed values, but spleen iron and hemoglobin levels were unchanged. 3-Methylthiopropionate, a possible metabolite in a proposed alternate pathway, caused a precipitous increase in spleen iron levels. Various methyl sources (betaine, choline, methyl acetate) when fed in excess failed to increase spleen iron levels. Methyl mercaptan and methyl mercaptoacetate likewise did not result in an increase in spleen iron deposition. Both the hemosiderosis condition and the reduced food utilization caused by excess methionine were reversed by supplemental glycine plus threonine.

Animals↗