G. F. Heuser

The Need for Manganese in Bone Development by the Rat.

Summary The length, density, breaking strength, and phosphatase content of the bones of manganese-deficient rats were lower than in pairmates of the same weight receiving adequate manganese. There was no difference between the two groups in percentage of ash, calcium, phosphorus, and magnesium in the fat-free dry bone.

The Folic Acid Requirement of Chicks for Growth, Feathering and Hemoglobin Formation.∗

Summary The folic acid requirement of chicks for growth, feathering, and hemoglobin formation has been determined using a purified diet containing 2.0 μg of preformed folic acid per 100 g of diet. The total folic acid content of the basal diets as determined microbiologically following incubation with chick liver was 5 μg per 100 g of diet for Experiment 1 and 15 μg for Experiments 2 and 3. The following amounts of folic acid, which include the amount in the basal diet, were required for its several functions: for survival to 6 weeks of age, approximately 25 μg per 100 g; for growth and hemoglobin formation at 4 weeks of age, 45 μg; for growth at 6 weeks, 45 μg, but for hemoglobin formation at 6 weeks, 35 μg; and for feathering at 6 weeks of age, not less than 55 μg per 100 g of diet. In these experiments the addition of succinylsulfathiazole at 1 or 2% of the diet did not have any effect on growth, feathering, or hemoglobin formation in chicks to 6 weeks of age.

Distribution of Vitamin B12 in the Organs and Tissues of the Chick.

Summary Microbiological data have been presented on the distribution of vit. B12 in the tissues and organs of chicks fed a purified diet containing a high level of vit. B12. Kidney was found to contain the most vit. B12 while liver and pancreas contain lesser quantities. Muscle, except for the heart, is low in vit. B12 under these conditions. A comparison of these results with other published data indicates that certain organs, particularly the kidney, liver and pancreas, have the ability to store appreciable quantities of vit. B12.

An Improved Method for the Microbiological Assay of Growth Factors on Paper Chromatograms.

Summary A simple, quantitative method for the microbiological assay of filter paper chromatograms has been described. Some possible applications have also been pointed out.

Further Studies of Factor R.

Summary The growth and hemoglobin responses obtained in chicks receiving a purified diet supplemented with factor R were found not to be due to the preformed folic acid present in factor R. By means of chick liver, rat liver, and hog kidney incubation procedures the folic acid content of factor R was greatly increased. This indicated the presence of potential folic acid which did not stimulate the growth of S. faecalis, but which was available to the chick. The potential folic acid liberated by hog kidney enzymes was found to account for all of the responses obtained in the chick, whereas chick and rat liver enzymes were not as effective in liberating folic acid. The most probable explanation for the discrepancy in the folic acid content of factor R obtained following hog kidney and rat or chick liver incubations is that factor R is a mixture of conjugates of folic acid rather than one conjugate. The response to factor R was not affected by the presence of succinylsulfathiazole in the diet. Conjugated folic acid appeared, therefore, to be available as such to the chick, or was made available by metabolic processes.

Response of anemic chicks to peteroylglutamic acid.

Summary Chicks deprived of pteroylglutamic acid (folic acid) for the first 4 weeks of life respond dramatically to a single administration of the vitamin given either orally or intramuscularly. The reticulocyte response preceded hemoglobin increase and reached a peak 4 to 6 days following administration. Intramuscular injection of pteroylglutamic acid was more than twice as effective as the same amount administered orally. The hemoglobin increase in 7 days was proportional to the amount of pteroylglutamic acid administered either by mouth or by intramuscular injection.

Influence of Diet on Chick Growth-Promoting and Antiperotic Properties of Betaine, Methionine and Choline.∗

Summary Betaine and methionine have been shown to be effective in preventing perosis and promoting growth in chicks when added to a simplified diet. They were ineffective when added to a purified diet of higher methionine content. In contrast, choline prevented perosis and promoted growth on both diets. The results indicate that choline is required as such for the prevention of perosis and for growth and that betaine and methionine when added to the simplified diet enabled the chick to synthesize choline. This may be caused by an unidentified factor present in the simplified diet which is necessary for choline synthesis. Another possible explanation is that a factor which inhibits choline synthesis is present in the purified diet. When the casein in the purified diet was replaced with an isolated fraction of the proteins of soybeans with resultant reduction in methionine content, betaine and methionine failed to prevent perosis but promoted some growth. The growth response obtained with betaine and methionine in this instance is believed to be due to a deficiency of methyl groups only. Choline was again effective for both purposes.

Further evidence for methylatable precursors of choline in natural materials.

In the course of work on choline metabolism in chicks the choline content of several diets was determined by both a colorimetric method and a microbiological method. The colorimetric method was essentially that of Thornton and Browne 1 using reineckate precipitation. Ethanol was used to extract the choline-bearing substances from the original materials. Hydrolysis was carried out with 3% H2SO4 and the precipitation was done after neutralization to pH 6.0 with solid Ba(OH)2 and then to pH 7.5 with 1 N NaOH. The microbiological method was that of Horowitz and Beadle 2 using the Neurospora “cholineless” mutant 34486. The standards as well as unknowns were passed through the adsorption and elution steps. Reproducibility was poor with the Neurospora method on some samples. The results are shown in Table I. On the purified and semipurified diets the 2 methods were in close agreement. On the practical diet with liver meal and the simplified diet, however, the Neurospora method gave substantially higher values. The simplified diet contained 15% peanut meal. The value of >0.08% obtained for the simplified diet by the Neurospora method is in essential agreement with that published by McGinnis, Norris and Heuser. 3 The value of <0.04% obtained by the reineckate method is in agreement with a value calculated from the choline contents of the individual ingredients as published by Engel. 5 The higher value obtained by Neurospora on the practical diet containing liver meal might be expected in view of the results of Jukes and Oleson. 6 These authors found that, if a crude aqueous extract of liver was hydrolized with Ba(OH)2 and then precipitated with reineckate, the resulting filtrate was active for Neurospora. Jukes and Dornbush 7 observed that dimethylaminoethanol stimulated the mutant Neurospora in a manner similar to choline. Apparently, however, dimethylaminoethanol was not precipitated by reineckate when pure and was only partially precipitated in the presence of choline.

A new bone deformity in the chick.

Summary A new bone deformity which is characterized by a twisting;of the tibia at the proximal end has been observed in chicks fed purified diets. Under the conditions of this experiment gelatin and fish meal decreased the incidence and severity of the malformation. The diet used appears to be deficient in an unknown factor or factors necessary for maximum growth and the prevention of the bone deformity.