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A method for comparing the availability to chicks of phosphorus from different sources has been described. It involves feeding graded increments of the phosphates in a diet very deficient in phosphorus and determining the resulting increases in bone ash after 4 weeks. For compounds of moderate or high availability, a purified type of diet very low in phosphorus was used. For studying poorly available compounds, a diet with satisfactorily low phosphorus content was formulated from ingredients of a practical type.

The comparative availability of a number of common phosphorus supplements and pure phosphate compounds has been studied by adding them singly to a basal chick diet very low in phosphorus. When used to raise the phosphorus content of the basal diet to 0.4%, the orthophosphates, including KH2PO4, pure betatricalcium phosphate and reagent grades of mono-, di-, and tricalcium phosphate, were excellent sources of phosphorus and slightly more available than steamed bone meal. At the same phosphorus level, the defluorinated superphosphate and defluorinated phosphate rock products used in these experiments were good sources of phosphorus, but less available than the pure orthophosphates or steamed bone meal.

1.Evidence is presented that comparable values for vitamin B12potency are obtained by chick growth and microbiological assays.2.Studies revealed that substances which replace vitamin B12in the metabolism of L. leichmanniican be differentiated equally well with paper partition chromatography or by destruction of the vitamin with alkali.3.Using the rapid microbiological assay method and the alkali correction procedure, a study of the vitamin B12content of feedstuffs and other materials was made. Fish meal and related products and liver products were found to contain appreciable quantities of vitamin B12, while cereals and their by-products were found to contain very little, if any, vitamin B12.4.Two vitamin B12activity peaks were obtained by paper partition of alfalfa meal extracts. The smaller, faster moving peak appeared to be due to thymidine. The other, slow moving peak may be due to a form of vitamin B12not destroyed by alkali, as its Rfvalue did not correlated with that of any of the known active desoxyribosides.

1The presence in the diet of manganese and certain of the other ‘trace’ elements has been found essential for the prevention of the deformity of the tibiae and metatarsi of chicks, known as perosis. Indications were also obtained that these elements exercised a favorable influence on growth.2The addition of 0.0025 to 0.015% of manganese to a diet containing 0.0010% of this element was sufficient to almost entirely prevent perosis.3Zinc and aluminum possessed a similar property but were somewhat less effective.4A mixture of manganese, aluminum and iron was entirely preventive in the presence of limited amounts of calcium and phosphorus.5The perosis-preventing property of certain cereal products was related to their content of manganese.

Studies have been made of the pantothenic acid requirement of hens fed a diet of purified ingredients supplemented with 4% of fish meal. Under these conditions, the requirement for maximum hatchability was found to vary somewhat, depending on the degree to which the hens were selected for hatchability. In 1 experiment, the requirement for hatchability was found to lie between 750 and 1000 µg of pantothenic acid per 100 gm of diet. In a second experiment although 650 µg supported optimum hatchability, it was found that at least 800 µg per 100 gm was necessary in the diet of the hens to promote best growth, and to prevent symptoms of deficiency and mortality in their progeny. It appears from the lower requirement obtained with the purified diet, that a deficiency in the heated diet previously used considerably increased the requirement for pantothenic acid. When hens depleted of pantothenic acid were supplied this vitamin, hatchability of their eggs returned to normal in 1 or 2 weeks.

Experiments have been completed the results of which showed that chicks require for normal growth two factors present in liver not identical with any nutrient previously reported to be needed. Both factors were found to be present in a 70% ethanol extract of the concentrated water-soluble material of liver. The results of counter-current distribution indicated that one of the factors is organic in nature and the other probably inorganic. Evidence was also obtained of the presence of a third chick growth factor in fish solubles.

Experiments were conducted with chicks to compare the antiperotic property of choline with that of betaine plus the methylaminoethanol compounds in the presence and absence of dietary folic acid.

In rachitic chicks it was found that the bone phosphatase is increased to an abnormally high level the same as in the rachitic rat. By omitting manganese from the rachitogenic diet, the bone phosphatase was decreased to approximately the normal amount. The difference in the phosphatase levels in the bones of groups of chicks fed rachitogenic diets, with and without an adequate quantity of manganese, was found to be much greater than the difference in the phosphatase levels in the bones of groups of chicks fed a non-rachitogenic diet, with and without an adequate quantity of manganese.

Evidence is presented which shows that pantothenic acid is required for reproduction in hens. It was found that for this function they require also an unidentified, heat stable factor, or factors, present in liver extract. The addition of pantothenic acid alone to the basal diet increased hatchability from zero to 10–30%. When it was added to the basal diet along with the factor, or factors, in liver extract, hatchability was increased to 50–60%. The factor, or factors, in liver extract had little or no influence on hatchability except in the presence of pantothenic acid. A dermatosis was observed on the feet and shanks of hens fed a diet deficient in pantothenic acid.

Vitamin B12-depleted chicks were fed a diet deficient in choline and methionine and lacking in vitamin B12. Supplementation with monomethylaminoethanol, homocystine and betaine was compared to choline and methionine at equimolar concentrations, both in the presence and absence of vitamin B12.

Evidence, obtained previously, of the existence of two unidentified chick growth factors, designated factor R and factor S, has been confirmed. Factors R and S have been found not to be identical with folic acid, the Lactobacillus casei factor or vitamin Bc. If the latter factors are the same substance, as recent work indicates, a new chick antianemic factor has been revealed which is distinct from factors R and S. This antianemic factor may be vitamin Bc, however, in the event that crystalline preparations of it are contaminated with highly potent growth and antianemic factors or stimulate their bacterial synthesis in the intestinal tract. No evidence was obtained that folic acid is, or is not, required by the chick, since growth failure and very extreme mortality occurred in the absence of the antianemic factor and factor R or the antianemic factor and factor S. If folic acid is required, the amount appears to be less than 15 μg. per 100 gm. of diet.