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IN A REVIEW of the amino acid requirements of the chicken, Almquist (1952) reported that the sulfur amino acid requirement appeared to be 0.8% of a diet containing 20% protein. This is the present requirement of the National Research Council (1954). Almquist also stated that the requirement for methionine and other essential amino acids increased as the protein content of the diet increased, but not to the same extent. He further noted that approximately 0.1% more methionine is required in the diet for maximum efficiency of feed utilization than is required for maximum growth. Hill (1953) reviewed the methionine and cystine requirements of the chick and concluded in agreement with Almquist (1952) that the total requirement for sulfur amino acids did not exceed 0.8% of a diet containing 20% protein. The results of three preliminary experiments reported in part by Hill (1953) showed that methionine added to practical broiler diets …

ONE of the most recent and interesting fields of research in animal production is the study of the effects of drugs and hormones which influence growth and metabolism. Both in large animals and in poultry, there is intense interest in the fundamental and practical aspects of the use of synthetic estrogens, antithyroid drugs, and thyroactive iodinated casein. The research to be reported here was undertaken because there was little information in the literature concerning the effects of these drugs upon the basal energy metabolism of chickens. In this work, these three classes of drugs were represented, respectively, by dienestrol diacetate, thiouracil, and Protamone (an iodinated casein product having thyroxine activity). Thiouracil is highly goitrogenic when fed to growing chickens at a level of 0.1 or 0.2 percent of the diet, as shown by Astwood, Bissell and Hughes (1944); Mixner, Reineke and Turner (1944); Andrews and Schnetzler (1946); and others. It …

Experiments were conducted to evaluate heated unextracted soybean fractions as sources of soybean oil and protein for the growing chick. Heated dehulled unextracted soybean flakes produced growth rate and feed efficiency equal to that obtained with the combination of soybean oil meal and degummed soybean oil while heated ground unextracted soybeans were less satisfactory in this respect. The poorer results obtained with ground unextracted soybeans were shown to be related to a poorer absorbability of the oil in them. Flaking the soybeans markedly improved the absorbability of the oil by the chick, probably by causing a greater disruption of cellular structure than was obtained by the grinding of the soybeans. The metabolizable energy of ground unextracted soybeans was substantially less than that of unextracted soybean flakes. Most of the differences in metabolizable energy were accounted for by differences in absorbability of the oil. Soybean hulls at a level equivalent to that contained in soybeans were found to have no effect on growth rate and only a slight effect on feed efficiency. Autoclaving soybean oil did not lower its value for the chick. The relationship between the poorer growth obtained with ground unextracted soybeans and the low absorbability of the oil in them was discussed. To obtain maximum efficiency in the use of unextracted soybean products in chick rations, some such means as flaking must first be employed to increase the availability of the oil.

QUANTITATIVE data on the utilization of fats and fatty acids by poultry are quite limited. Whitson et al. (1943) described an index method for determination of digestibility using barium sulfate, and showed that soybean oil is highly digested and absorbed by growing chickens. Duckworth et al. (1950) found that linseed oil is well utilized by chicks, but mutton tallow is much less well absorbed. Their data indicated that the absorbability of mutton fat increased with age. Carver et al. (1955) found that beef tallow was well utilized when added at a level of 3% to a practical broiler ration. Hydrogenated tallow and the fatty acids of hydrogenated tallow were less well absorbed, while oleic acid showed high absorbability. Sunde (1956) obtained evidence that the hard fats, tallow and hydrogenated tallow, when fed at a level of 5% in a practical chick ration were less well utilized than softer inedible fats …

SOYBEAN oil is an excellent source of energy for chicks and also will stimulate growth rate when included in certain types of chick diets (Dam et al., 1959; Carew, 1961). Therefore it is desirable to study various means by which soybean oils may be easily incorporated into diets for chicks. Since soybean protein is the most widely used source of amino acids for poultry rations, unextracted soybeans, which contain approximately 20% soybean oil, offer a simple means of supplying most of the amino acids as well as the beneficial properties of soybean oil to chick diets in the form of a single feed ingredient. Previous reports from this laboratory have shown that finely ground, heat-treated soybeans do not serve as an efficient source of soybean oil for the chick because the soybean oil present in the soybean is poorly digested (Renner and Hill, 1960; Carew et al., 1961). Whereas extracted …

THE nutritive value of cottonseed meal for chickens and other non-ruminant species is influenced by at least four factors. The toxicity of gossypol has been long recognized; the minimum dietary level of gossypol which is detrimental to growth and development has been reported to be as low as .016 percent (Heywang and Bird, 1955) and as high as .08 percent (Couch, Chang and Lyman, 1955) and has been shown to vary with the level of dietary protein (Narain et al., 1960). The relative lysine deficiency of cottonseed protein is also well established, and this may be further aggravated by reaction of lysine with gossypol and other constituents of the seed during processing (Kuiken, 1952). A third factor is the extent of heat damage to the protein during processing, as suggested by the general correlation of nutritive value with protein solubility (Lyman et al., 1953). The development by genetic selection of…

FATS from several sources have been reported to stimulate growth rate when added to diets for chicks. Included in this group are the oils derived from corn, peanuts, cottonseed and soybeans, egg oil, and lard. The reports on this subject have been reviewed by Rand et al. (1958), Hill et al. (1958), Dam et al. (1959), Denton and Menge (1959), Carew et al. (1959) and Menge and Denton (1961). This effect of certain fats on growth rate may reflect the presence of a required nutrient or may be related to the higher caloric density of diets containing added fat. Results which would support the latter possibility have been presented for fats of both animal and vegetable origin. Work by Baldini and Rosenberg (1957) showed that growth responses to beef tallow did not occur when energy levels of diets containing added fat were maintained isocaloric to that of the low-fat basal…

IN A previous paper by Baker et al. (1957) the effects of feeding Nicarbazin to laying hens on the yolk quality of their eggs was described. Neither the nature of the damage to the yolk nor the mechanisms involved in causing the damage were known. Experiments were designed to study the possible mechanisms involved. MATERIALS AND METHODS Eggs were obtained from hens fed Nicarbazin. The scoring system used to estimate yolk damage was the same as described previously (Baker et al., 1957). Water uptake of the yolk was determined according to the method of Orru (1939). The intact yolk was dried on filter paper, placed in a tared beaker and covered with the experimental solution. The system was incubated at 37°C. for 3 hours, the fluid drained off and the last traces of solution removed with filter paper by rolling the yolk over the paper. It proved to be practically . . .

ON THE basis of the available evidence from quantitative studies, the Committee on Animal Nutrition of the National Research Council (1954) has estimated the vitamin A requirements to be 1,200 U.S.P. units per pound of diet for growing chickens, and 2,000 U.S.P. units per pound of diet for laying and breeding hens. The results of individual studies on which these estimates are based have varied widely. The sources of vitamin A activity used in the various studies on requirement were fish oils, alfalfa meals and/or yellow corn, all of which were unstable to some degree, especially after mixture in the experimental diets. Even with the precaution of frequent diet mixing, the instability of the vitamin or its precursors introduced considerable uncertainty into the quantitative estimates of requirement. Recently, efforts in industry have been directed toward the development of vitamin A preparations which are highly stable in diet mixtures and under…

DURING the winter of 1956 several field cases were reported to the Experiment Station of flocks of hens in which a large percentage of the freshly laid eggs showed abnormalities of the yolk. The yolks seen in these field cases and subsequently produced experimentally were blemished by a combination of translucent and opaque areas with the result that the color of the yolk surface was not uniform. In many eggs, whitish-yellow “curdled” areas were evident, and in severe cases the yolk had a brownish-orange color and was streaked. These yolks were apparently similar to those described by Jeffery (1945). The studies reported here were undertaken to determine the possible cause of the yolk damage observed in the field cases. MATERIALS AND METHODS During the experiments described below, eggs laid the previous day were broken out on a glass plate supported between mirrors so that all the surfaces of the yolk . . .

Several groups of research workers have reported the existence of unidentified members of the vitamin-B complex required by the chick for the prevention of nutritional deficiency. Among these are factor U of Stokstad and Manning (1938), factor R and factor S of Schumacher, Norris and Heuser (1940), vitamin Bc of Hogan and Parrott (1940), and vitamin B10 and vitamin B11 of Briggs, Luckey, Elvehjem and Hart (1943). Factor U, factors R and S and vitamin B11 were reported to be required for chick growth, vitamin Bc, for the prevention of anemia and vitamin B10 for feather development. These discoveries were made by making use of specially devised experimental diets. As a consequence no evidence was obtained of the need for any of these vitamins in practical chick feeding. Recently, however, results have been obtained at this laboratory which show that certain chick rations containing limited amounts of protein of animal . . .

Singh and Shaffner (1950) have reported that a very small amount of thyroprotein (1 gram per 100 pounds of feed) completely overcame the depression of basal metabolic rate (BMR) due to 0.2 percent of thiouracil in the diet of two-week-old chicks. Moreng and Shaffner (1949) reported that the same level of thyroprotein in combination with 0.2 percent thiouracil produced larger goiters in chicks than those produced by thiouracil alone. The level of thyroprotein used by these workers was one-fourth that which Schultze and Turner (1945) found would maintain normal thyroid size in growing chickens fed thiouracil, and therefore is presumably equivalent to one-fourth the normal thyroxine secretion. For this reason, plus the unexpected nature of the findings with respect to thyroid size, it was considered desirable to determine whether results similar to those of the Maryland workers could be obtained in another laboratory. Eighty-day-old male chicks (BPR × RIR) were randomly …

MENGE and Combs (1952) reported that orotic acid stimulated only very slight and inconsistent growth responses when fed to chicks. Similar results were obtained by Chin and Norris (1953). In contrast Combs, Arscott and Jones (1954) obtained increased growth in chicks fed practical type diets supplemented with orotic acid. Rasmussen et al. (1954) also reported that orotic acid promoted chick growth. DeBusk and Williams (1955) observed a growth response in chicks on addition of thioctic acid to the diet. Stokstad, Broquist and Patterson (1953), Morrison and Norris (1956), Stokstad et al. (1956), Reid et al. (1956), Supplee, Combs and Romoser (1956) and Briggs and Fox (1957) on the other hand, were unable to show that thioctic acid increased chick growth under a variety of environmental and dietary conditions. Barnett et al. (1956) reported a growth increase in chicks on the addition of adenosine to a purified diet. Ritchey, Scott and…

A marked growth stimulating effect of certain fats in purified chick diets has been reported by Rand et al. (1958), and Dam et al. (1959). The latter workers have also shown that soybean oil, effective in purified diets, produces a significant improvement of growth rate when added to a ration composed of practical feedstuffs and typical of those used in commercial broiler production. Further studies in this laboratory have been conducted to investigate the use of heat-treated ground soybeans as a source of soybean oil for improving growth on practical rations, but without success (Norris et al., 1958). A possible explanation of these findings has been found in other work (Renner and Hill, 1959) in which the metabolizable energy of heated ground soybeans was substantially less than that expected from prior knowledge of the values of soybean oil meal and soybean oil, due to poor digestibility of the oil in …

THE GROWTH promoting effect of the addition of unsaturated fats to low fat diets for chicks has been demonstrated with diets based on isolated soybean protein and glucose by Rand et al. (1958) and Dam et al. (1959). However, Bieri et al. (1956) reported that there was no growth response at 4 weeks of age to the addition of 4% corn oil to a low fat diet based on casein, gelatin and glucose. The following study was conducted to determine the effect of protein source on the growth promoting action of soybean oil. EXPERIMENTAL Day old White Plymouth Rock chicks obtained from a commercial hatchery were randomly distributed, and housed in battery brooders with raised wire floors and thermostatically controlled electric heaters. Duplicate lots of 10 male chicks were used per treatment. Feed and water were supplied ad libitum. Purified low fat diets were prepared with isolated soybean protein, fillet …