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A rapid bioassay method for comparing xanthophyll availability from various sources or the pigmenting ability of genetic strains or crosses is proposed. Xanthophyll depleted, fasted birds are intubated with equal amounts of xanthophyll from various sources. Serum xanthophyll is then determined from blood samples obtained 14 to 24 hr following intubation. Results are expressed as the increase in serum xanthophyll (μg/ml) over the intubated controls per milligram xanthophyll intubated per kilogram body weight. Limitations of the bioassay are discussed.

Xanthophyll depleted, fasted broilers were intubated with various xanthophyll sources in a series of six experiments. The increase in serum xanthophyll per milligram xanthophyll intubated per kilogram body weight was used to estimate exahtnophyll availability. Statistically significant differences among samples within and among generic sources were obtained. As a result, beta-apo-8'-carotenoic acid ethyl ester (apo-EE) was used as a reference standard in Experiments 4 to 6. When the availability of apo-EE was given a relative value of 100, the availability of xanthophyll from corn gluten meal ranged from 47.7 to 89.1% (four samples), from dehydrated alfalfa, 34.6 to 65.4% (eight samples), and from Coastal Bermudagrass, 18.8 to 27.9% (three samples).

MANY practical poultrymen have been questioning for years the idea of “pushing” pullets along as rapidly as possible prior to the time of laying. Their observations have led them to believe that the pullets produce bigger eggs at a faster rate if their maturity is delayed somewhat either by restricting the food intake or by formulating a ration in which some nutrient is limiting. Usually energy or protein has been the limiting factor in these diets. Recently an added incentive for using some type of a restricted program has been the high cost of feed for growing replacement pullets. Recently Milby and Sherwood (1953) reported that restricted feeding did not materially affect egg production, egg weight or mortality but did delay sexual maturity about 2 weeks. Two years ago an experiment was initiated to study this problem. The two years data are available on Single Comb White Leghorn pullets which …

RECENTLY wheat germ oil has been advertised as a desirable addition to the ration for the poultry breeding flock. Consequently many poultrymen are asking if it is necessary or desirable to add this material to their rations. Card (1929) reported no improvement in fertility or hatchability when 2 percent wheat germ oil was added to a mixed grain ration. Card, Mitchell, and Hamilton (1930) working with pullets that had been fed rations treated with an etheral solution of ferric chloride to destroy vitamin E showed that there was an immediate and marked improvement in hatchability when one-half cubic centimeter of wheat germ oil per hen per day was fed. The authors state “Although these results are of considerable scientific interest it should be pointed out that from a practical feeding standpoint there is little cause for concern with regard to possible vitamin E deficient rations because all whole grains and . . .

MOORE et al. (1946) reported that the addition of streptomycin and sulfasuxidine to a purified diet brought about a growth response in chicks. The antibiotics did not cause a sterilization of the intestinal tract of chicks, but did produce a marked reduction in the coliform bacteria of the cecal contents. In 1947, Newell et al. reported that with a practical ration, combinations of dried penicillin mycelium and fish press water resulted in excellent growth of chicks. Later work by Cunha et al. (1949a), McGinnis et al. (1949) showed that an aureomycin mash A.P.F. concentrate was superior to vitamin B12 for swine and turkey poults. Stokstad et al. (1950) and Whitehill et al. (1950) reported the activity of the antibiotics in stimulating growth of chicks fed all vegetable type rations. Thayer et al. (1950) presented data which indicated that an A.P.F. concentrate has a sparing effect on the protein needs of . . .

STUDIES on the effect of heat on the nutritive value of proteins have been reported by many workers, Morgan and King (1926), Evans and McGinnis (1946), Block, Cannon, Wissler, Steffee, Straube, Frazier and Woolridge (1946), Hankes, Riesen, Henderson and Elvehjem (1948) and others. It was shown by Clandinin, Cravens, Elvehjem and Halpin (1947) that practical chick rations containing only overheated soybean oil meal as a supplementary source of protein were deficient in methionine and lysine. These deficiencies were corrected by the addition of the crystalline amino acids. The work of Riesen, Clandinin, Elvehjem and Cravens (1947) showed that there was a marked decrease in the enzymatic release of the essential amino acids of soybean oil meal which had been overheated when compared with correctly heated meal. They took three samples of soybean oil meal, one raw, one autoclaved at 15 pounds pressure for 15 minutes, and one autoclaved at 15 . . .

IN AN effort to design a ration deficient in methionine, but adequate in all other nutrients, it was decided to use peanut meal as the source of protein for a study of the methionine requirement of the laying hen. In addition to methionine, the available figures on the amino acid content of peanut meal indicates that lysine and tryptophan might also be low (Lyman et al., 1947). All rations were, therefore, supplemented with both of these amino acids. In previous studies by Ingram et al. (1950), it was shown that lysine and tryptophan deficient rations did not affect the amino acid composition of the egg, while on the other hand, Csonka et al. (1947) have reported that the methionine and cystine content of the egg could be modified by the diet fed the hen. In order to determine if a methionine deficiency would affect the composition of the egg, it . . .

DURING the course of experiments designed to determine the folic acid requirement of laying and breeding hens (Cravens and Halpin, 1949; and Sunde et al., 1950b), certain embryonic deformities were observed. Further it was observed that a high proportion of the embryos from deficient hens died during the latter stages of the developmental period. We wish to describe herein these symptoms as well as to present data showing the effect on hatchability of injecting folic acid into the egg in varying quantities and at different times of incubation. Data showing the relation between the type of carbohydrate in the diet and the incidence of abnormal embryos and the time required to deplete the breeding hen of folic acid will also be presented. EXPERIMENTAL METHODS The management of the hens has been described by Cravens and Halpin (1949). Four to twelve Single Comb White Leghorn pullets were placed on each ration. . . .

NUMEROUS experiments have shown that the addition of green feeds improves poultry breeding rations. These experiments have, to a large extent, been designed to show the value of green feeds as sources of carotene and riboflavin (Hunt, Winter, and Bethke, 1939; Williams, Lampman, and Bolin, 1939; Halpin and Holmes, 1936; Sherwood and Fraps, 1932, 1934, and 1935; Bearse and Miller, 1937). Alfalfa leaf meal and dried cereal grass have also been shown to be excellent sources of vitamin K (Almquist and Stokstad, 1936; Cravens, Randle, Elvehjem, and Halpin, 1941. Hunt, Winter, and Bethke (1939) have presented evidence that alfalfa leaf meal contains some factor other than carotene or riboflavin which is required for satisfactory reproduction in poultry. The experiments to be reported herein were designed to compare alfalfa leaf meal and dried cereal grass 1 as supplements to laying and breeding rations. The relative value of these two supplements as sources . . .

AFTER pteroylglutamic acid (P.G.A., folic acid) became available in sufficient quantities for experimental work, Taylor (1947), Schweigert, et al., (1948) and Cravens and Halpin (1949) have reported on the quantitative requirements of the breeding hen for this vitamin. Taylor (1947), using a rice-fishmeal ration reported that 0.12 mg. of P.G.A. per kilogram of ration was essential for egg production, while somewhat in excess of this amount was required for satisfactory hatchability. Schweigert, et al., (1948), using a ground corn-casein ration, reported that the requirement was between 0.12 and 0.42 mg. per kilogram of ration. Cravens and Halpin (1949) reported that approximately .5–1.0 mg. per kilogram of diet are required for normal hatchability when sucrose is used as the source of carbohydrate, and that probably not over .25 mg. per kilogram of diet is required by the laying hen. The studies to be reported herein were initiated to establish more . . .

DRIED skimmilk and alfalfa leaf meal have been used as the primary sources of water soluble vitamins in laying and breeding rations that are composed largely of grains, grain by-products and high protein feeds. The scarcity and cost of these materials, the milk products in particular, makes it essential that we evaluate other supplements as possible sources of water soluble vitamins for poultry rations. Fish solubles, a by-product of the fishing industry, is one such product. Riboflavin is also now available in crystalline form and the proper way to use this vitamin should be determined. Clandinin, Traves and Henderson (1942) reported that crystalline riboflavin satisfactorily replaced dried buttermilk in breeding rations composed of ground cereals, cereal by-products, alfalfa meal, fish meal, mineral sources and fish oil. Bird and Marvel (1943) have also reported that riboflavin is the only supplement essential in a breeding ration composed of ground cereal, cereal by-products, . . .

Competition of urea with oilseed proteins in ruminant feeding depends primarily on economic relationships between these ingredients, cost of energy sources and proper feed formulation. A general summary of the more important factors to consider in replacing protein with nonprotein nitrogen in ruminant feeds is presented. Estimated urea utilization in the U.S. grew at a 15.5% compound annual rate from 1962 to 1966. From 1966–1969, usage increased at a 5% compound annual rate. Approximately 650,000 tons of urea were used by the U.S. Feed industry in 1969. Urea usage is expected to continue to grow in the United States. The high cost of energy sources in Western Europe will tend to slow its use by the feed industry of that area. In general, competition of urea with oilseed proteins will be greatest with heavy grain feeding of cattle, low cost grains and high priced oilseed meals.

SummaryEvidence is presented to show that biotin is essential for normal embryonic development in the hen's egg. A satisfactory synthetic ration for use in studies of the vitamin requirements of laying and breeding hens is also presented.

THE phosphorus requirements of laying pullets have not been extensively studied. Branion (1938) concluded that mineral supplements should be fed ad libitum due to the disparity in the calcium and phosphorus requirements as found by various investigators. Miller and Bearse (1934) stated that approximately 0.80 percent phosphorus was required for optimum production when the fixed calcium content of the ration was 2.23 or 3.00 percent. Norris et al. (1934) found that 0.5 percent phosphorus was not sufficient for egg production but 0.75 percent was adequate. In 1937 Mitchell and McClure expressed the requirement by standardizing the production at 75 percent and phosphorus availability at 50 percent. Under those conditions the requirement was calculated to be 0.35 percent phosphorus. Schaible (1941) reviewed the literature and concluded that 0.4 percent phosphorus was required but to allow for a margin of safety 0.5 percent was recommended. Evans and Carver (1942) stated the phosphorus …

INTRODUCTION THE effect of vitamin B12 on hatchability has been demonstrated by a number of workers. Lillie, Olson and Bird (1949) found that the injection of vitamin B12 into eggs from hens depleted in this vitamin markedly improved hatchability. The beneficial effect of feeding APF concentrates (containing B12 or B12 and antibiotics) on hatchability has been reported by Lindstrom et al. (1949), Olcese et al. (1950), and Carver and Mc-Ginnis (1950). Elam et al. (1951) have presented data which they interpret as showing that antibiotics stimulate egg production and hatchability. The experiments to be reported herein deal with the use of vitamin B12 and vitamin B12 and antibiotic feed supplements in laying and breeding rations of birds maintained under practical conditions. Data on the relation between built up litter and hatchability are also presented inasmuch as Kennard et al. (1948) and Halbrook et al. (1950) have stressed the value of . . .

IN A series of papers; Rose and co-workers (1936); Rose (1937); Womack, Kemmerer and Rose (1937); Womack and Rose (1941), presented evidence proving the dispensability of cystine and the indispensability of methionine in the diet of the rat. These workers also showed that cystine is capable of stimulating growth in rats only if the diet is suboptimal in methionine. Their findings indicate that on a cystine deficient diet, body cystine arises from dietary methionine and that on a suboptimal methionine diet, cystine included in the diet has methionine sparing action. That the sulphur of cystine synthesized in the body actually originates from methionine was established by Tarver and Schmidt (1939) and confirmed by Rose and Wood (1941). The relationship between choline, homocystine and methionine was worked out by du Vigneaud et al. (1939) who showed that in the presence of choline, homocystine is capable of replacing methionine in the diet . . .

In previous papers (1,2) evidence was presented to show that condensed fish solubles produced a marked increase in the growth rate of chicks on diets containing an adequate level of vitamins and essential amino acids. Berry, Carrick, Roberts, and Hauge (3) found that a water extract of fish solubles was also active in stimulating the growth of chicks. Very little other information on the properties of the unidentified growth factor in fish solubles is available. The present investigation was undertaken to study some of the properties of the factor.

SummaryAminopterin, injected prior to, or early in, the incubation period, is highly toxic to the chick embryo. Ten micrograms or more of this compound produce 100% mortality; 100 μg or more per egg completely inhibit embryonic development. The inhibitor becomes relatively less toxic as embryonic development progresses; at nine days or more, twenty micrograms is non-toxic. The same amount injected at three days results in almost immediate embryonic death.Thymidine partially counteracted the inhibitory effects of aminopterin. A combination of hypoxanthine desoxyriboside and thymidine was more effective than thymidine alone. In the absence of thymidine, hypoxanthine desoxyriboside was without effect. An enzymatic digest of desoxyribonucleic acid also counteracted aminopterin inhibition partially. Thymine, hypoxanthine, folic acid, vitamin B12, and concentrates of the Leuconostoc citrovorum factor, alone and in various combinations, were ineffective in counteracting aminopterin inhibition.These experiments i...

IN A previous study by Ingram, Riesen, Cravens and Elvehjem (1949) it was found that a good measure of the biological value of the protein of soybean oil meal for chick growth could be obtained by subjecting the meal to enzymatic hydrolysis and then measuring the amounts of certain amino acids that were liberated in a given period of time. The soybean oil meal samples were first subjected to acid hydrolysis and the amino acid content determined microbiologically. After enzymatic hydrolysis similar determinations were carried out and the percentage of the amino acids liberated by the enzymes calculated. Good correlation was found between these values and the growth supported by the same soybean meal samples in chicks. The studies reported here were undertaken to determine if this in vitro technique would also accurately measure the relative biological value of different cottonseed meal samples. Since the work of Olcott and Fontaine . . .

SummarySeveral purine bases and related nucleosides were tested for their effectiveness in potentiating the reversal by thymidine of aminopterin inhibition of the chick embryo. Of the free purine bases, hypoxan-thine was most active; adenine and guanine were also active, while xanthine was inactive. Of the nucleosides tested, only inosine was active. Inosine was more active than hypo-xanthine; together with thymidine it completely overcame the effects of the low level of aminopterin employed. The results are interpreted to mean that aminopterin prevents embryonic growth by preventing synthesis of compounds essential for formation of nucleic acids; by supplying these substances preformed, growth occurs even though amino-pterin is present. It follows that thymidine, and the active purine bases and derivatives listed above, are utilizable for nucleic acid synthesis by the chick embryo.

BRANION (1938) concluded that the ratio of calcium to phosphorus was not of prime importance to the growing chicken when vitamin D was present at an optimal level. With adequate vitamin D and reasonable levels of calcium and phosphorus the Ca:P ratio could vary from 1:1 to 3:1 with an optimum of 2:1. However, the absolute amounts of calcium and phosphorus were important for optimal growth and bone ash. The amount of phosphorus required was stated as 0.4 percent and to insure an adequate amount 0.5 percent was recommended. Since this review, considerable evidence has accumulated indicating that the phosphorus requirement of the growing chicken is greater than 0.4 per cent. Couch et al. (1937) suggested that a level of 0.76 to 0.81 percent phosphorus was adequate for normal growth and calcification of chicks up to twelve weeks of age. Lowe et al. (1939) concluded that much of the work …

IT HAS been demonstrated by numerous investigators that a number of products of marine origin exert a beneficial effect on the growth of chicks, when added to certain practical rations. Christiansen, Deobald, Halpin and Hart (1940), Carver and Evans (1943), Hammond and Titus (1944), in investigations of diets containing a high level of soybean oil meal found that the addition of fish meal to such a diet resulted in more rapid growth of chicks. Cravens, McGibbon and Halpin (1945) noted a similar growth promoting effect when fish press water and ground fish viscera were added to a chick ration composed of yellow corn, wheat by-products, meat scrap, soybean oil meal, minerals, fish oil and riboflavin. Berry, Carrick, Roberts and Hauge (1945) demonstrated that fish press water, fish liver meal and animal liver meal were satisfactory supplements to a chick diet containing all vegetable protein. They found further that the water . . .

THE minimum requirement for sodium chloride for optimum performance by breeding hens fed purified diets has been investigated. In previous work (Barlow et al., 1943; Halpin et al., 1934; 1936; Prentice, 1933; Sjollema, 1935) with sodium chloride in the nutrition of poultry, optimum rather than minimum requirements were sought, and levels from 0.5 to 1.0% were accepted as adequate. In the present investigation, the actual need with purified diets was found to be considerably lower. The data on the effect of sodium chloride deficient diets on the performance of breeding hens are also presented. EXPERIMENTAL Single-Comb White Leghorn pullets which had been reared to maturity on range and fed practical diets were placed in individual cages with raised screen bottoms and throughout the experiments were given water, oyster shell, and ration ad libitum. The purified basal ration used was complete in all known nutrients except the minerals; its composition in . . .

IN A previous report (Ingram et al., 1950) it was shown that corn gluten meal supplemented with tryptophan and lysine as the source of protein in an otherwise purified diet would support a fair rate of production in the laying hen. Egg production on this ration was 47 percent while the omission of either of the above amino acids resulted in much lower egg production. Cravens (1948) had shown that a ration composed largely of corn and corn gluten meal when fed to the laying hen would maintain the hen in laying condition for an extended period of time. Using this ration, he obtained approximately 38 percent egg production in a fifteen week experiment. In an effort to determine the lysine and tryptophan requirements of the laying hen, it was decided to use a corn-corn gluten meal ration supplemented with lysine and tryptophan. EXPERIMENTAL Single Comb White Leghorn pullets were . . .

THE phosphorus requirements for growing chickens have been studied chiefly by means of rations containing considerable cereal products. This has complicated the estimation of the requirement for phosphorus by the growing chicken due to the poor availability of phytin phosphorus as shown by Lowe, Steenbock and Krieger (1939) and Heuser, Norris, McGinnis and Scott (1943). Mitchell and McClure (1937) and Mitchell (1947) have assessed the phosphorus requirements of poultry and have shown that the requirements should decrease with increasing body size. However, most experiments on phosphorus requirement of chickens have consisted of feeding the same levels of phosphorus for the entire experimental period, thus masking any change in the actual requirements with advancing age or increasing body size. In considering the comparative nutritional requirements of different classes of farm animals, Guilbert and Loosli (1951) observed that the recommended allowances of phosphorus for growing chickens remain constant with advancing age whereas . . .

THE growth response in chicks resulting from dietary supplementation with arsenicals has been found to be about equal to that obtained with antibiotics. Frost (1953) has reviewed the discovery and elucidation of this phenomenon. Published information concerning the toxicity of arsanilic acid for the chick is limited. Frost (1953) reported data showing that the deposition of arsenic in chicken tissue resulting from dietary arsanilic acid is a function of the level in the feed. Arsenic was found to be non-cumulative in tissue when a comparatively low level of arsanilic acid was fed. Elam et al. (1953) reported that arsanilic acid increased growth of chickens and decreased the number of Clostridia in the feces as did several antibiotics. This finding suggests that the mechanism of growth stimulation might be the same for antibiotics and arsenicals. Waibel et al. (1952) reported that dietary thiamine was spared by penicillin in a purified ration …

THIRTY-FIVE years ago Osborne and Mendel (1914) demonstrated the effect of tryptophan and lysine deficiencies on the growing rat and various workers have since shown that a deficiency of any one of the essential amino acids has a similar effect. Extensive studies have established, within rather narrow limits, the requirements of the rat (Rose, 1937, and Frazier et al., 1949), the chick (Almquist, 1947) and the human (Rose, 1949) for the essential amino acids. However, there has been very little work reported on the requirements of the laying hen. Cravens and Halpin (1946) and Cravens (1948) using nine percent casein and seven percent gelatin as sources of protein demonstrated the effect of a leucine deficiency and a multiple amino acid deficiency on the laying hen. Grau and Taylor (1948) reported that zein supplemented with arginine, histidine, methionine, cystine, threonine and valine plus lysine and tryptophan supported forty-one percent egg production . . .

SEVERAL factors are responsible for the radical changes being made in the composition of poultry rations. Wartime shortages of various feedstuffs have, of course, made certain changes essential. However, even before the war, the trend was toward the use of larger quantities of vegetable proteins and less of those of animal origin. Also at times the alfalfa products commonly included in poultry rations have been difficult to obtain and of poor quality. Synthetic riboflavin and other materials rich in this factor are becoming cheap and readily available and are often suggested as a replacement for dried milk. The following experiments were conducted to determine whether or not satisfactory results would be obtained if the alfalfa leaf meal and dried milk are replaced with vitamin A from fish oils and synthetic riboflavin in rations containing a limited quantity of animal protein. EXPERIMENTAL For sake of brevity only three experiments will be . . .

THE adverse effect of heat upon the nutritive value of cereal proteins was demonstrated by Morgan and King (1926). Since the publication of their paper numerous other reports dealing with the effect of heat on the nutritive value of various proteins have appeared. Reference to much of the literature on this subject will be found in the papers by Greaves, Morgan and Loveen (1938) and Block et al. (1946). The adverse effect of excessive amounts of heat on soybean proteins has been reported by Mussehl (1942), Bird and Burkhardt (1943), and Evans and McGinnis (1946). In the studies reported herein an attempt has been made to determine vitamin and amino acid deficiencies that exist in over-heated soybean oil meal. EXPERIMENTAL Single Comb White Leghorn chicks were used in these experiments. In order to have chicks of comparable growing capacity in each group the following method of selecting chicks was adopted. . . .

IN A previous report Robblee, Nichol, Cravens, Elvehjem and Halpin (1947) presented evidence that condensed fish solubles contain an unidentified factor capable of causing an increase in the growth rate of chicks fed on a diet apparently complete in recognized growth essentials. The magnitude of the response was such that it appeared to be adaptable to a biological assay of the factor. Several other reports have appeared in which other materials have been noted to exhibit growth promoting activity for the chick. Berry, Carrick, Roberts and Hauge (1945) found that both liver meal and fish solubles caused a stimulation in growth on a natural ration, and a similar effect with liver meal was observed by Scott, Norris and Heuser (1947) with a purified ration. Rubin and Bird (1946) have reported the presence of a growth factor for chicks in cow manure and found that fish meal also resulted in an . . .

THE increased use of vitamin B12 and/or antibiotic feed supplements in practical chick feeding has created much interest in the advisability of removing all of the animal protein feedstuffs from the starting ration. Evidence that chicks fed an all vegetable ration supplemented with vitamin B12 will grow normally has been presented by Ott el al. (1948), Lillie el al. (1948) and Nichol el al. (1949). Shortly thereafter Stokstad and co-workers (1949) observed that certain fermentation products were more effective in promoting growth of young chicks than would be expected from their B12 content. Later Stokstad and Jukes (1950) observed that the addition of crystalline aureomycin hydrochloride to the chick ration also gave a growth response above that obtained by B12 alone. Still later Menge, Combs and Shorb (1949) reported a factor being present in dried liver and whey which increased the rate of growth of chicks when added to a . . .

SummaryDesoxypyridoxine (1000 fig) injected into eggs prior to the start of the incubation period resulted in 100% mortality of the embryos; this inhibition was prevented by simultaneous injection of any of the three forms of vitamin B6. The ratio of vitamin to inhibitor which permitted approximately 50% of the embryos to produce live chicks was 1/20 for pyridoxal, 1/50 for pyridoxamine and 1/100 for pyridoxine.When injected after 4 or more days of incubation, 1000 μg of desoxypyridoxine proved non-toxic. Higher levels injected at 6 days of incubation proved toxic but this toxicity could not be prevented by any of the 3 forms of vitamin B6. A possible explanation for this observed variation in toxicity of desoxypyridoxine at different stages of incubation is offered. Pyridoxal hydrochloride and pyridoxine hydrochloride also proved toxic at high levels while pyridoxamine dihydro-chloride was not toxic at the highest level tested.Neither nicotinic acid nor its amide affected the inhibitory action of desoxyp...

DURING the course of studies designed to determine the effect of choline on egg production and hatchability, a purified ration was formulated which was inadequate for laying hens. The ration was designed to be low in choline and methionine. However, the addition of these two factors failed to complete the ration for laying hens. The ration used was identical in composition to ration B21 (Table 1) except that it contained no choline and corn oil was used in place of soybean oil. Inasmuch as choline or methionine alone or in combination were ineffective supplements, experiments were undertaken to determine what other deficiencies existed in the low choline ration. The studies to be reported herein demonstrate that leucine is an important amino acid for laying hens and further that either or both tryptophane and methionine are essential. A preliminary report on part of this work was given by Cravens and Halpin . . .

INTRODUCTION THE availability of vitamin B12 concentrates makes it desirable to determine the value and limitations of such products in practical chick starting rations. The activity of vitamin B12 for growing chicks has been demonstrated by Ott, et al., (1948), Lillie, et al., (1948) and Nichol, et al., (1948). However, none of the diets used were of a practical nature. Therefore, studies were initiated to compare the effect of a vitamin B12 concentrate with fish solubles in rations such as might be used in practice. EXPERIMENTAL METHODS Straight run chicks (New Hampshire male × Single Comb White Leghorn female) were the progeny of hens fed, managed and cared for as described previously (Robblee, et al., 1948). After wing-banding, the chicks were kept in standard electrically heated batteries. They were weighed weekly. Mortality was negligible in all lots. Each trial was for a four week period except for one broiler trial. . . .

IN THE fall of 1938 two groups of pullets were placed on special rations in order to have a uniform source of chicks for encephalomalacia studies. One group of pullets was fed a practical ration of grain and mash except that no alfalfa leaf meal was included in the mash. The other group received a ration composed largely of yellow corn and dried skimmilk. After the hens had been on the rations for about five months the chicks hatched showed extensive hemorrhages at wing banding, some even bleeding to death. The disorder was demonstrated to be vitamin K deficiency by a determination of the blood clotting time of a number of the chicks. A survey of the literature revealed little information concerning the vitamin K requirements of breeding hens. Almquist and Stokstad (1936) reported that the vitamin K reserves of day-old chicks, as measured by survival time on a vitamin . . .

SummaryConcentrates of the Leuconostoc citrovorum factor (CF) and of “folinic acid” partially counteract the inhibitory action of aminopterin for the chick embryo. Folic acid and formylfolic acid were ineffective or only slightly effective under the same conditions. The magnitude of the effects obtained with CF were similar to those obtained previously with mixtures of thymidine and hypoxanthine desoxyriboside 1). The viewpoint is developed that conversion of folic acid to CF is a necessary preliminary to the catalytic action of the former compound, that synthesis of thymidine and one or more of the purine desoxyribosides are among the synthetic reactions for which CF or folic acid) is required, and that these synthetic reactions are those inhibited in the chick embryo by small amounts of aminopterin. The great variation that exists in the ability of CF to counteract aminopterin inhibition in various organisms is pointed out.

In an attempt to develop a more suitable assay for an unidentified factor found in fish solubles and liver products (Sunde et al. 1950) a modification of the ration of Carlson et al. (1949) was formulated. The basal ration consisted of the following in percent: sucrose 66, soybean oil 5, salts V (Phillips and Hart, 1935) 6, alpha protein * 22, vitamin A and D feeding oil (3000A-400D) 0.5, glycine 0.3, DL methionine 0.3, L cystine 0.3, choline chloride 0.2, and B12 concentrate #3 (Merck) 0.2. The following vitamins were added as follows in mg. per kg.: thiamine HC1 6, riboflavin 12, niacin 100, Ca pantothenate 40, pyridoxine HC1 8, biotin 0.4, menadione 0.5, i-inositol 2000, alpha tocopherol 3, folic acid 4, and para-amino benzoic acid 100. All additions to the basal were made at the expense of sucrose. The dextrin is autoclaved corn starch. Straight run chicks (New Hampshire × . . .

IN A previous paper, Cravens, Sebesta. Halpin and Hart (1943) demonstrated the essential nature for pyridoxin for egg production, hatchability and the maintenance of body weight in mature fowl. Although 1.0 mg. of added pyridoxin per kilogram of ration appeared to give results comparable to the higher levels fed, no attempt was made from this experiment to define the requirements of laying hens for this vitamin. We wish to report here the results of a further experiment designed to determine the pyridoxin requirements of laying and breeding hens. EXPERIMENTAL Single Comb White Leghorn pullets from the Experiment Station flock were used in this experiment. These birds were reared on range and placed in an individual cage laying battery September 1, 1942. From this time until December 14, 1942, when the experimental feeding was started, the birds were fed a practical breeding mash with grain. Just prior to the experimental period, . . .

SummaryConcentrations of 0.05% to 5% Crotalaria spectabilis seed were fed to chicks. All concentrations of the legume were shown to be toxic. Concentrations in excess of 0.3% produced death in all birds within 18 days. When less than 0.2% was fed there was a marked reduction in weight gain. In birds which died, hemorrhage was frequently observed in liver, lungs and the pericardium. Atrophy of liver and ascites were constantly encountered in test birds after death.