Inadequacy of Certain Salt Mixtures Used in Studies of Unidentified Growth Factors for Chicks

740

RESEARCH NOTES

T A B L E 1.—Average gain and feed efficiency of chicks fed thioctic acid Average weight gain

14 gm. Experiment 1 Basal 112 +10 meg. dl-thioctic acid per kg. 98 +100 meg. dl-thioctic acid per kg. 114 +1,000 meg. dl-thioctic acid per kg. 102 +10,000 meg. dl-thioctic acid per kg. 97 Experiment 2 Basal 95 +2,000 meg. dl-thioctic acid per kg. 95 + 1 % sulfasuxidine 98 +2,000 meg. dl-thioctic acid + 1 % sulfasuxidine 98

diet

28

%m. 328(35)*

0.605

308(35)

0.605

338(36)

0.605

315(35)

0.621

310(36)

0.606

338(36)

0.676

345(35) 324(34)

0.667 0.671

338(36)

0.680

experiment by including thioctic acid in the basal diet. The results of these experiments, therefore, confirm the observations of Stokstad, Broquist and Patterson (1953) and are in disagreement with those of DeBusk and Williams (1955). In view of the fact that the latter research workers obtained growth stimulation in both chicks and rats by adding thioctic acid to the diet, it seems probable that the cause of the discrepancy in the results is not due to a difference in source of the experimental animals, but rather to unexplained differences in environmental conditions.

* Figures in parentheses indicate number of survivors.

differences in gain in either experiment was statistically significant even at the 10% level. In agreement with the growth data, the ratio of the weight gains to feed consumed was also not improved in either

REFERENCES D e B u s k , B . G., a n d R . J . W i l l i a m s . 1955. Effect of lipoic acid o n t h e growth r a t e of y o u n g chicks a n d r a t s . A r c h . Biochem. B i o p h y s . 5 5 : 587-588. S t o k s t a d , E . L . R., H . P . B r o q u i s t a n d E . L . P a t t e r son. 1953. Role of protogen in a n i m a l n u t r i t i o n . F e d . Proc. 1 2 : 4 3 0 .

INADEQUACY OF CERTAIN SALT MIXTURES USED IN STUDIES OF UNIDENTIFIED GROWTH FACTORS FOR CHICKS G. M. BRIGGS Laboratory of Biochemistry and Nutrition, National Institutes of Health, Public Health U. S. Department of Health, Education, and Welfare, Bethesda, Maryland

Service,

(Received for publication April 7, 1956)

It is known that chicks require several unidentified growth factors, one or more of which may be inorganic. In order to secure unequivocal evidence for the existence of such unidentified growth factors, it is essential that the basal diet used provide all of the known essential nutrients at levels that are high enough to permit the best possible growth. In a number of published reports it appears that less emphasis has been given to the adequacy of known mineral elements than to that of vitamins and amino acids. In our own studies on unidentified fac-

tors, with New Hampshire chicks, we were unable to get growth responses from the addition of the ash of crude feedstuffs to a purified diet (sucrose-soybean protein). The diet contained a salt mixture (Briggs et al., 1952) which supplied the known essential minerals in amounts greater than the minimum levels recommended by the National Research Council (Bird et al., 1954). One explanation for the inactivity of the ash in our experiments might be that chicks from depleted hens had not been used. However, in attempting to find other explanations, we noted that the

RESEARCH NOTES

salt mixtures used in some of the published work of others might be partially deficient in certain known minerals. This could conceivably account for at least part of the reported response to ash and to crude materials. One example of what appears to be an inadequate salt mixture is that used by Dannenburg et al. (1955) who studied an inorganic growth factor present in the ash of distillers' dried solubles. This salt mixture apparently supplied only 0.12% of potassium to the ration (as provided by 0.258% of K 2 HP0 4 and by KI). This compares with the minimum requirement of 0.2% of potassium suggested by the N.R.C. The authors stated that in subsequent studies addition of potassium was tested and found to be without effect; however, no data were given concerning the level and source of potassium tested or the amount present in the soybean protein in the diet. The authors also stated that "the basal diet was checked with regard to the mineral supplement and found to meet the N.R.C. recommended levels of the minerals," contrary to the values presented.1 They also stated that "the calcium content of the ration was 1.08% and it was thought this level might be a little low under the conditions of our experiments." However, a calculation of the values in their paper shows the 1 The authors might also have checked the level of vitamins to compare with N.R.C. levels since the amount of pyridoxine used, 2.0 mg. per kg., does not meet the N.R.C. minimum requirement of 2.86 mg. Also, the indicated level of vitamin B12 fed dams of the chicks was stated to be 50 mg. per pound of diet. This is presumably a typographical error since more than likely 50 micrograms were used. Another salt mixture used to study inorganic growth factors by this same laboratory (Reid et al., 1955) supplies an unusually high level of calcium. The exact amount is not known since whether or not hydrates of the salts were used is not reported. Also, there are several obvious errors in the amounts of some of the salts used.

741

calcium content of the ration to be 1.23% (supplied by 3.37% CaHP0 4 and 0.58% CaC0 3 ). Several other instances of salt mixtures deficient according to N.R.C. standards have been pointed out (Anonymous, 1956). For example, Fisher et al. (1954), in studies on unidentified growth factors in alfalfa, liver, and whey, used a salt mixture which supplied 0.25% of MgS0 4 • 7H 2 0 in the purified diet. This provided only 250 mg. of magnesium per kg. of diet compared with a minimum requirement of 484 mg. suggested by the N.R.C. (Bird et al., 1954). This salt mixture was also used by Scott et al. (1955) in a recent paper on unidentified growth factors. Although results obtained by feeding magnesium or the ash of liver and whey were not reported, the ash of alfalfa (Fisher et al., 1954) and the ash of distillers' solubles (Scott et al., 1955) did not increase the rate of growth according to the authors' conclusions.2 This would indicate that the amount of magnesium in the basal diet was perhaps borderline or sufficient, even though not up to N.R.C. minimal standards. 3 It has also been pointed out (Anonymous, 1956) that the salt mixture of Petersen et al. (1955), used in studies on 2 In the studies of Scott et al. (1955) growth with the ash of distillers' solubles was equal to that obtained with distillers' solubles in one of the four replicates. In two replicates out of four the combination of ash plus distillers' solubles appeared to be somewhat better than the distillers' solubles alone. It should be pointed out that no mention is made in the paper of Scott et al. of the inclusion of a source of vitamin K in the diet due to a typographical error (Scott, personal communication). 3 According to Scott (personal communication) and Fisher (personal communication) the N.R.C. value for magnesium appears to be more than twice the actual minimum requirement under their conditions. Thus, their diets may not have been deficient in magnesium except as measured by N.R.C. standards.

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RESEARCH NOTES

unidentified factors for chicks, does not come up to N.R.C. standards in regard to manganese, phosphorus, or calcium. Calculation of several other salt mixtures used in recent chick experiments on unidentified factors shows them to be complete, including the mixture used by Morrison et al. (1955) in studies on an unidentified mineral response. These comments are not meant to throw doubt on the existence of unidentified factors, but they are intended as a reminder for nutritionists to use a salt mixture which has been fully tested for proper balance and for adequacy according to N.R.C. standards. Even though serious deficiencies may not exist,.studies on unidentified factors made with inadequate salt mixtures are open to question unless full details are given concerning other possible sources of minerals in the diet. REFERENCES Anonymous, 1956. Unidentified growth factors for chicks. Nutrition Reviews, 14: 75-79.

Bird, H. R., H . J. Almquist, W. W. Cravens, F. W. Hill and J. McGinnis, 1954. Nutrient requirements for poultry. National Academy of Sciences, National Research Council, Washington, D. C , Publication 301. Briggs, G. M., M. R. Spivey, J. C. Keresztesy and M. Silverman, 1952. Activity of citrovorum factor for the chick. Proc. Soc. Exp. Biol. Med. 81: 113-115. Dannenburg, W. N., B. L. Reid, E. E. Rozacky and J. R. Couch, 1955. An inorganic chick growth response. Poultry Sci. 34: 1023-1026. Fisher, H., H. M. Scott and R. G. Hansen, 1954. Further studies on the alfalfa factor and its relation to the liver and whey factors. J. Nutrition, 52:13-24. Morrison, A. B., M. L. Scott and L. C. Norris, 1955. Evidence for an unidentified mineral required by the chick. Poultry Sci. 34: 738-740. Petersen, C. F., A. C. Wiese and A. R. Pappenhagen, 1955. Unidentified chick growth factors. 1. Purified assay diet and crude supplement response. Poultry Sci. 34: 673-678. Reid, B. L., E. E. Rozacky and J. R. Couch, 1955. An inorganic chick growth response. Poultry Sci. 34:1217-1218. Scott, H. M., W. D . Morrison and P. Griminger, 1955. Studies on unknown growth factors in distillers' dried solubles. Poultry Sci. 34: 1446-1447.

BOOK REVIEWS (Continued from page 738) farm products; IV—Adjustment of consumption and supply; V—Marketing agencies, channels and costs. The term "marketing" as used in this book describes a series of "services" involved in getting goods from the "point of production" to the "point of consumption." In the preface the authors state, "The book is based on the conviction that the real spark of value in a course in agricultural marketing comes from giving the students a grasp of the whys of the marketing process. With this in mind we have given special attention to the economics of consumption emphasizing those characteristics of consumers and the trade which are so influential in setting the pattern for both production and marketing." The authors have done just this by covering material concerning consumer behaviour, buying practices and food habits. The services which have been performed by the consumer are considered and this is generally neglected. The authors show why food consumption varies from family to family, from one day to another, from one section of the country to

another. They have covered the fact that there is a market for both high and low quality products. The variations in consumption and production which influence many marketing functions are explained and how these functions bring consumption and production into balance. A real foundation for the treatment of the mechanics of marketing is presented in the book. The emphasis has been given to the practical rather than the theoretical and academic. This book is highly recommended to all teachers of agricultural marketing and poultry husbandry.— W.D.T. in World's Poultry Science Journal Heuser, G. F., Feeding Poultry (2nd ed.), John Wiley and Sons, Inc., New York, N.Y. 632 p., $7.50. A casual perusal only, of this book, to say nothing of a thorough reading, will show that it is a "must" for the student, teacher or research worker in poultry husbandry, and for the feed manufacturer. In addition it should have a place in the library of the

(Continued on page 743)