HIGH PHOSPHORUS IN HEN DIETS 1253

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1 HIGH PHOSPHORUS IN HEN DIETS 1253 the sole source of supplemental protein to be used with corn (Table 2). Since comparable results were obtained with the cornsoybean meal diet containing a phosphorus level equivalent to the meat meal diet it would appear that this depression was due primarily to the phosphorus content of the meat meal. However, that a part of this depression may have been caused by an imbalance and/or amino acid deficiency cannot be ignored since this was not investigated. SUMMARY Two experiments conducted with laying hens maintained in cages indicates that high levels of phosphorus will depress performance. It would appear that caged hens will tolerate a higher level of phosphorus than birds maintained on the litter. It is postulated that this difference is due to the higher phosphorus requirement of caged hens. Replacing all of the soybean meal in the diet with meat and bone meal depressed performance of the laying hen. This depression of performance was attributed primarily to the high phosphorus content of the meat meal since equivalent phosphorus levels in the corn-soybean diets resulted in a comparable depression, however, a part of this may have been due to amino acid imbalance or deficiency. ACKNOWLEDGMENT This work was supported in part by a grant-in-aid from Smith Douglass Company, Inc., Norfolk, Virginia. REFERENCES Crowley, T. A., A. A. Kurnick and B. L. Reid, Dietary phosphorus for laying hens. Poultry Sci. 42: Duncan, D. B., Multiple range and multiple F tests. Biometrics, 11: Harms, R. H., C. R. Douglas and P. W. Waldroup, The effects of feeding various levels and sources of phosphorus to laying hens. Florida Agri. Exp. Sta. Bui Singsen, E. P., A. H. Spandorf, L. D. Matterson, J. A. Serafin and J. J. Tlustohowicz, Phosphorus in the nutrition of the adult hen. 1. Minimum phosphorus requirements. Poultry Sci. 41: Snedecor, G. W., Statistical Methods, Iowa State College Press, Ames, Iowa. Titus, H. W., The Scientific Feeding of Chickens. The Interstate Printers and Publishers, Inc., Danville, Illinois. The Effect of Cereal Grain and Energy Level of the Diet on the Response of Turkey Poults to Enzyme and Antibiotic Supplements 1 EDWIN T. MORAN, JR. AND JAMES MCGINNIS Department of Animal Sciences, Washington State University, Pullman (Received for publication March ) THE differences in growth response to antibiotics reported by different investigators have been attributed to several factors, among which are "old" and "new" 1 Scientific Paper No. 2629, Washington Agricultural Experiment Stations, Pullman. Project No environment (Coates et al., 1951; Gordon, 1952), continued use and induced resistance (McGinnis et al., 1958; Nelson et al., 1963), as well as a reduced germ load or diseased potential with continued use of an antibiotic (Libby and Schaible, 1955; Waibel et al., 1954).

2 1254 E. T. MORAN, JR. AND J. MCGINNIS TABLE 1. Composition of protein basap Ingredient Soybean meal (50% protein) Herring fish meal (70% protein) Meat and bone scrap (50% protein) Brewer's dried yeast Dehydrated alfalfa meal (17% protein) Dicalcium phosphate Dried whole whey Iodized salt Trace mineral mix 2 Premix 3 %of total diet Calculated to contain 26.6% protein. 2 Trace mineral mix supplied per kilogram of diet: manganese, 49.9 mg.; iron, 49.9 mg.; calcium, 49.9 mg.; copper, 4.99 mg.; zinc mg.; iodine, 1.52 mg.; and cobalt, 0.51 mg. 3 Supplied per kilogram of feed: vitamin A, 5,5001.U.; vitamin D 3, 1,650 I.C.U.; riboflavin, 3.3 mg.; pantothenic acid, 3.3 mg.; niacin, 17.6 mg.; choline, 495 mg.; ethoxyquin, 125 mg. Growth responses attributed to enzyme supplementation also may vary due to several causes. Fry et al. (1958b) found that the type of cereal grain influences the degree of response by turkey poults, while Willingham et al. (1960), using samples of barley grown in different geographical areas, showed that the geographical source of the grain may also influence the response. The results presented in this paper show that the growth response of turkey poults to antibiotic and/or enzyme supplements may also be influenced by the energy level and/or cereal grain of the ration. GENERAL PROCEDURE Broad Breasted Bronze turkey poults were randomly distributed at day of age into raised wire pens of electrically-heated brooder batteries and given their respective diets and water ad libitum. They were raised from hatching to 4 weeks of age in all trials except Experiment 2, in which they were placed on experiment at 1 week of age. Five replicate groups of 5 or 10 birds per pen (see footnotes of respective tables) were fed each experimental diet. Body weight and feed consumption were recorded weekly. A basal premix (Table 1) was incorporated into each diet at a constant level of 55 parts in the total diet. The energy was controlled at the desired calorie-level by manipulation of grain, corn oil and sand in the 45 parts ordinarily filled by the grain portion of the ration (see respective tables). In all diets the grain and basal premix were pelleted and crumbled separately to minimize diet density effects. The antibiotics used were oleandomycin (2.2 mg./kg.), zinc bacitracin (5.5 mg./kg.) and streptomycin sulfate (11.0 mg./kg.). The enzyme supplement used in all cases was "Bacterial Amylase A" 2, which was incorporated in the diet at a level of mg./kg. The 4 week weight data were subjected to the analysis of variance, in accordance with a completely randomized design (Federer, 1955), followed by Duncan's multiple range test (1955) at the 5% level of probability to determine significance of treatment differences. RESULTS Experiment 1 was designed to test the effect of oleandomycin and enzyme supplementation of diets containing either corn or barley as the cereal grain. Growth of poults fed the diet with corn (Table 2) was not affected by the antibiotic or enzyme supplements nor the combination. In contrast, both enzyme and oleandomycin significantly (P > 0.05) improved growth when added to the diet containing barley and a combination of enzymes and oleandomycin further increased the growth re- 2 A crude bacterial fermentation product of Bacillus sub tills origin, obtained from Chas. Pfizer & Co., Terre Haute, Ind. (Lab B.A. No ).

3 ENZYMES AND ANTIBIOTIC RESPONSE 1255 sponse (P > 0.05) above either supplement alone. The feed efficiency of the poults fed the corn diets was unaltered by either supplement, whereas the barley-containing diet was improved by all supplements. Supplementation with either enzyme or oleandomycin significantly improved the feed efficiency above the basal and were not different from each other. The combination of enzyme and oleandomycin proved significantly better than both the basal or either supplement alone. Feces from all birds receiving the basal barley diet were "sticky" and adhered to the wire floor. This effect was not observed in any of the birds fed diets with corn. When diets with barley were supplemented with enzyme or enzyme and antibiotic the wire floor remained clean but oleandomycin alone had no effect on the feces even though it markedly improved growth. Experiment 2 was designed to compare the effectiveness of bacitracin and streptomycin in addition to oleandomycin on growth of poults fed diets containing either barley or corn as the cereal grain. Broad Breasted Bronze turkey poults were raised TABLE 2. The effect of cereal grain component of diets on the response of turkey poults to antibiotic and enzyme supplements {experiment 1) Treatment Oleandomycin* Enzyme 6 Oleandomycin* -(-Enzyme 6 4 wt"- 1 G / F3 617 a a a a wt> / F3 346 d c c b 1 Calculated to contain: 30.4% and 30.6% protein; 1599 and 1940 productive kilocalories per kilogram in corn and barley diets, respectively. 2 Average of 5 pens of poults, 10 poults per pen. 3 Gain/feed consumed. 4 Duncan's multiple range test at 5% level; treatments with a different letter are significantly different from each other. * Oleandomycin, 2.2 mg./kg. 6 Pfizer "Bacterial Amylase A," mg./kg. TABLE 3. The effect of cereal grain component of the diet on the response of turkey poulls to various antibiotic supplements (experiment 2) Treatment Oleandomycin* Bacitracin* Streptomycin* \ W 1 G / F3 542 b a b b W T"- G/ F3 437 d c c c All poults were 1 week of age when started on experiment and had received regular starter containing 5.5 mg. bacitracin per kg. 2 Average of 5 pens of poults, 10 poults per pen. 3 Gain/Feed consumed. 4 Duncan's multiple range test at 5% level; treatments with a different letter are significantly different from each other. * Antibiotic levels: Oleandomycin, 2.2 mg./kg.; zinc bacitracin, 5.5 mg./kg.; streptomycin sulfate, 11.0 mg./kg. to one week of age on the standard university starting ration which contained bacitracin and then placed on the experimental diets. The experimental diets were then fed until the turkeys were 4 weeks of age. As the results in Table 3 show, the type of grain in the ration influenced the growth response to an antibiotic. Only oleandomycin gave a significant growth response in the series fed diets with corn; bacitracin and streptomycin were without effect. In contrast, all three antibiotics gave a significant growth response when added to diets containing barley. Again as observed in Experiment 1, none of the antibiotics affected the adherence of feces to the wire floors. Experiment 3 was conducted to determine whether or not the energy level of the diets containing corn or barley would influence the response of turkey poults to enzyme and oleandomycin supplementation. The results in Table 4 illustrate that the energy level of the diet affected the response of turkey poults receiving either corn or barley-containing diets to supplements of enzyme or antibiotic. The birds

4 12S6 E. T. MORAN, JR. AND J. MCGINNIS TABLE 4. The effect of dietary grain and energy level on growth and feed efficiency of turkey poults fed antibiotic and enzyme supplements {experiment 3) Ingredient diets Sand' ' oil % diets Ingredient oil oil % E/P 1 24, 25 29, 29 36, 34 Treatment -{-Oleandomycin 5 4-Enzyme fi -{-Oleandomycin +Enzyme -{-Oleandomycin -f- Enzyme -j-oleandomycin -{-Enzyme -{-Oleandomycin -{-Enzyme -{-Oleandomycin -{-Enzyme 4 wk. wt.' 521 e< 546 cd 511 e 568 be 525 de 550 cd 526 de 587 ab 464 f 565 be 503 e 571 be G/P wk. wt. 1 1 Energy to protein ratio as kilocalories of productive energy to percentage protein, corn and barley, respectively. 2 Average of 5 pens of 10 poults per pen. 3 Gain/Feed consumed. * See footnote 4, Table 2. 5 Oleandomycin, 2.2 mg./kg. Pfizer "Bacterial Amylase A," mg./kg. 7 The sand in this diet appreciably increased the density of the diet. fed corn diets with the lowest energy level (13% sand and 32% corn) showed a significant response to oleandomycin alone and the combination of oleandomycin with enzyme, but not the enzyme alone. Growth of poults fed the diet containing 55 parts corn (intermediate in energy level) was not improved by enzyme supplementation but the response to oleandomycin approached significance. The combination of supplements gave a significant growth response above all other treatments in the same energy level. 3 Increasing the energy level of the diet with corn as the grain (9% corn oil and 36% corn) caused a significant growth depression. Oleandomycin overcame this depression while the enzyme supplement only partially prevented it. The antibiotic-enzyme combination gave no greater response than the antibiotic alone. Poults fed barley diets at all energy levels responded significantly to either enzyme or oleandomycin supplementation. 3 This result is in opposition with the results in Experiment 1, and felt to be due to unequal sex distribution within the treatment. 420 g* 532 e 473 f 593 ab 429 g 612 a 508 e 566 be 384 h 570 be 467 f 557 c G/F» The birds receiving the lowest energy barley diet (45% barley) responded significantly to both oleandomycin and enzyme supplementation. The combination of supplements was significantly better than either one alone. Poults fed the barley diets, intermediate in energy (37.5% barley and 7.5% corn oil) also responded significantly to all three treatments. The oleandomycin supplement alone proved significantly better for poults than the enzyme-antibiotic combination but in a later trial (Table 5), they proved equivalent in growth-promoting ability. Growth of birds fed the basal of the highest energy level (30% barley and 15% corn oil), was significantly depressed below that normally encountered with barley alone. Supplementation of the diets with antibiotic alone or the antibiotic-enzyme combination resulted in complete recovery from the depression while the diets containing enzyme alone, though significantly improving growth, did not equal that of the antibiotic or the combination. Experiment 4. The effect of increasing increments of corn in barley-containing diets on the response of turkey poults to

5 ENZYMES AND ANTIBIOTIC RESPONSE 1257 TABLE 5. The effect of replacing barley with corn in isocaloric diets on the growth response of turkey poults to oleandomycin and enzyme supplementation {experiment 4) Level of % Ingredient oil oil oil oil Diet Composition % Average of 5 pens of 5 poults per pen. 2 Gain/feed consumed. 3 See footnote 4, Table 2. 4 Oleandomycin, 2.2 mg./kg. 6 Pfizer "Bacterial Amylase A," mg./kg. oleandomycin and enzyme supplements was tested in this experiment. All diets were maintained isocaloric at 1940 kilocalories of productive energy per kilogram by appropriate addition of corn oil at the expense of barley (Table 5) for each respective level of corn. The results in Table 5 show that corn did not improve growth of turkey poults fed the basal diets until it comprised 20% of the ration and a level of 30% was required before the inherent growth depression due to barley was overcome. It is quite significant to note that the antibiotic promoted equivalent growth at all levels of corn, whereas the enzyme was no longer effective in stimulating growth when the level of corn reached 30%. The antibioticenzyme combination was no better than - Treatment +01eandomycin 4 +Enzyme 5 +Oleandomycin+Enzyme +01eandomycin -(-Enzyme -(-Oleandomycin+Enzyme +Oleandomycin +Enzyme +01eandomycin+Enzyme -(-Oleandomycin +Enzyme -f- Oleandomycin+Enzyme 4 wk. wt h be 475 g 554 cde 443 h 560 bed 528 f 594 a 486 g 561 bed 564 be 596 a 547 e 572 b 548 de 569 b G/F a the antibiotic alone at the 0 and 30% levels of corn, but was significantly better at the 10 and 20% levels. DISCUSSION is known to contain 1-3% of a polysaccharide, (3-glucan, which is considered responsible for its growth-depressing properties (Rickes et al., 1962; Jensen, 1964). This depression may be overcome when the enzyme, ^-glucanase is present either as an enzyme supplement or presumably elaborated by appropriate bacteria during water treatment of barley (Fry et al., 1958a; Willingham et al., 1959; Jensen, 1963). Since the growth depression of poults fed barley basal rations is considerably greater than might be expected from a reduction in energy equivalent to

6 1258 E. T. MORAN, JR. AND J. MCGINNIS the ^-glucan fraction other factors must be involved in the growth depression. That a factor other than energy is involved is indicated by both the work of Rickes et al. (1962) and Moscatelli et al. (1961). Rickes et al. (1962) found that a level of % of their 2,600 fold concentrated and electrophoretically pure i^-glucanase derived from B. sub tills added to a barley diet produced three-fourths of the maximum response obtained when corn was used in the diet of chicks. Moscatelli et al. (1961) has shown that (3-glucanase catalyzes hydrolytic scission of internal bonds of partially degraded barley (3-glucan, producing chiefly 3-0-^-D-cellobiosyl- D-glucose and 3-0-^-D-cellotriosyl-D-glucose. Thus, the products from (3-glucanase action may, for the large part, be presumed unavailable to the chick due to the absence of appropriate endogenous enzymes to further degrade the derived ^-linked saccharides. In turn it seems logical that the response to the enzyme is not necessarily due to an action which increases available energy but to the destruction of the (3-glucan polymer for which the enzyme is specific (Moscatelli et al., 1961). It should be noted that in the present studies a crude enzyme supplement was used and thus, it is quite possible that the products of (3- glucanase action could be further degraded to forms, notably glucose, which would be available to the chick. The results of the present study have shown that growth depression of turkey poults due to barley can effectively be eliminated by either an enzyme supplementation (^-glucanase active preparation) or the antibiotic oleandomycin. From these primary results a hypothesis has been developed which proposes that barley adversely affects growth and feed utilization of poults by supporting an "unfavorable" intestinal microflora. That barley does support an undesirable microflora is indicated indirectly through the exhibited poor growth, feed efficiency and "sticky" nature of the fecal matter voided by the birds fed the barley basal rations. Furthermore, that the (3-glucan fraction of the barley is responsible is substantiated by the work of Rickes et al. (1962) in which significant improvement of chick growth was obtained by barley rations using the purified {3-glucanase enzyme. Also, attempts to overcome the depression by increased proportions of corn alone in isocaloric basal diets are strongly resisted. The replacement of 10% barley with corn was ineffective; 20% replacement proved significantly better while 30% replacement, or 50% of the grain component of the diet, completely overcame the growth depression. If the (3-glucan does support the "establishment" of an "undesirable" microflora then the destruction or alteration of the (3-glucan might be expected to result in an improvement in growth and feed efficiency through alteration or modification of the intestinal microflora. That this is the case is supported by previous work on water treatment, enzyme supplementation (Fry et al, 1958a; Willingham et al., 1959; Willingham et al., 1960; Anderson et al., 1961) and with the purified enzyme itself (Rickes et al., 1962). The experimental results presented herein further support this hypothesis. The enzyme significantly improves growth, feed efficiency and eliminates the fecal problem in birds fed barley but has no effect when corn is used, probably because corn contains little or none of such complex polysaccharides. Vohra and Kratzer (1964) have studied the effects of other naturally-occuring complex polysaccharides on chick growth. When fed at the 2% dietary level, they observed growth depressions of the same order as those obtained with barley. It is also interesting that the depression encountered when 4%

7 ENZYMES AND ANTIBIOTIC RESPONSE 1259 pectin was incorporated into the diets was substantially alleviated by supplementation with the enzyme pectinase. Again assuming that the J3-glucan fraction of barley supports the "establishment" of an "undesirable" flora, then appropriate antibiotics should be able to affect this condition. Oleandomycin, bacitracin (routinely used in this laboratory), and streptomycin all significantly stimulated growth and increased feed efficiency in poults fed barley diets, but had no effect on the "sticky" fecal condition. On the other hand, bacitracin, streptomycin and oleandomycin had no significant effect or only slight effects when the poult diets contained corn. The data presented in Table 4 show that even when energy, in the form of corn oil, was added to the basal barley rations there was no improvement in growth even though the feed efficiency was increased. However, when oleandomycin was added to these barley rations, growth was significantly improved in all instances with the response being the greatest with those poults receiving additional energy. Of further significance are the data of Table 5 where the isocaloric barley rations containing various levels of corn all gave equivalent growth when oleandomycin was incorporated. Arscott et al. (19SS) and Fry et al. (1958a) attributed the poor nutritional value of barley to its lower energy when compared with corn since they could improve the growth of chicks by appropriate fat addition to the diets containing barley; however, both groups included antibiotics in their basal rations. In every case of the present study where barley comprised the entire grain fraction (45%) of the diet the combination of antibiotic and enzyme gave a significant response above either one alone (Tables 2 and 4). Upon consideration of the deficiency of energy in the barley diet when compared to corn (1599 and 1940 kilocalories of productive energy per kilogram of diet) it seemed logical that any added energy could significantly improve growth. As mentioned earlier, it seemed possible that the crude enzyme supplement might further avail energy from the products of (3-glucanase action, thus further stimulating growth. That the enzyme supplement alone does not promote this level of growth in poults indicates that it is not as effective as the antibiotic in the maintenance of a "favorable" microflora when fed with barley diets. That energy seems to be the factor in this improved growth and efficiency by the poults fed the barley ration with the combination of supplements is shown by the data of Tables 4 and 5 in which the growth increment obtained with the combination of supplements is lost by addition of energy to the diet. Anderson et al. (1961), using a diet containing 62% of a variety of hull-less barley with 1% corn oil and 22 mg./kg. of chlortetracycline or zinc bacitracin, mentioned that the kind of antibiotic seemed to affect the response to the enzyme supplement; however there were no values for the basal without either enzyme or antibiotic. Further studies reported in the same publication on the value of fat demonstrated that as the level of cottonseed oil was increased in the former diet there was increased growth of chicks and the response to the enzyme supplement decreased. Arscott (1963), feeding a barley diet to chicks containing zinc bacitracin, found that replacing one-eighth of the barley with corn resulted in significant improvement in both growth and accumulated droppings; however, after the corn was autoclaved the growth was reduced to that of barley and accumulated droppings increased to that of barley, suggesting that corn, like barley (Willingham et al., 1960) is subject to variation in (3-glucanase activity with geographical source. Thus, it

8 1260 E. T. MORAN, JR. AND J. MCGINNIS seems apparent that with appropriate antibiotics (antibiotics which can affect the hypothesized unfavorable microflora) in the diet the enzyme effect is one of availing energy when barley comprises the entire grain component. containing rations may, under certain conditions, be improved by oleandomycin or enzyme supplementation. The data of Table 4 illustrate that in corn diets where the energy-to-protein relationship was extensively altered, significant improvement in poult growth occurred with either enzyme or oleandomycin supplementation. Particularly noteworthy is the improvement in growth of birds fed diets high in energy (2380 kilocalories/kilogram) supplemented with either enzyme or antibiotic where little or no improvement was attained at other energy levels. SUMMARY Experiments were conducted to determine the effect of enzyme and antibiotic supplementation on the growth of poults fed diets containing either corn or barley as the cereal grain. Enzyme and antibiotic supplementation had essentially no effect on growth of poults when added to corn diets unless the protein to energy relationships were extensively altered. Poults fed barley-containing diets responded to enzyme and antibiotic supplementation in all trials, but did not respond to increased energy alone. A tentative hypothesis to explain the effect of barley on growth of poults and the responses to enzymes and antibiotics is presented. This hypothesis proposes that the (3-glucan fraction of barley supports the establishment of "undesirable" microflora which in turn proves detrimental to both poult growth and feed efficiency. This "undesirable" microflora may be modified either directly by the use of an antibiotic or indirectly through the use of supplemental enzyme concentrate which can degrade the (3-glucan. REFERENCES Anderson, J. O., D. C. Dobson and R. K. Wagstaff, Studies on the value of hull-less barley in chick diets and means of increasing this value. Poultry Sci. 40: Arscott, G. H., Use of barley in high efficiency broiler rations. 6. Influence of small amounts of corn on improvement of barley. Poultry Sci. 42 : Arscott, G. H., L. E. Johnson and J. E. Parker, The use of barley in high efficiency broiler rations. 1. The influence of methionine, grit and stabilized animal fat on efficiency of utilization. Poultry Sci. 34: Coates, M. E., C. D. Dickinson, G. F. Harrison, S. K. Kon, S. H. Cummins and W. F. J. Cuthbertson, Mode of action of antibiotics in stimulating growth of the chick. Nature, 168: 332. Duncan, D. B., Multiple range and multiple F tests. Biometrics, 11: Federer, W. T., Experimental Design. The MacMillan Co., New York. Fry, R. E., J. B. Allred, L. S. Jensen and J. Mc Ginnis, 1958a. Effect of pearling barley and of different supplements to diets containing barley on chick growth and feed efficiency. Poultry Sci. 37: Fry, R. E., J. B. Allred, L. S. Jensen and J. Mc Ginnis, 1958b. The influence of enzyme supplementation and water treatment on the nutritional value of different grains for poults. Poultry Sci. 37: Gordon, H. A., A morphological and biochemical approach in a colloquium: Studies on the growth effect of antibiotics in germ-free animals, held June 4, 1952, at Lobund Institute, University of Notre Dame, South Bend, Indiana. Jensen, L. S., Use of enzymes in animal feeds. Proceedings of California Animal Industry Conference. Jensen, L. S., Dietary enzymes for poultry feeds. Western Feed, April. Libby, D. A., and P. J. Schaible, Observations on growth responses to antibiotics and arsonic acids in poultry feeds. Science, 121: McGinnis, J., L. H. Merrill, R. E. Fry and L. S. Jensen, Use-history of antibiotics as related to their efficacy in promoting growth in turkeys. Poultry Sci. 37:

9 ENZYMES AND ANTIBIOTIC RESPONSE 1261 Moscatelli, E. A.. E. A. Ham and E. L. Rickes, Enzymatic properties of a 3-glucanase from Bacillus subtilis. J. Biol. Chem. 236: Nelson, F. E., L. S. Jensen and J. McGinnis, Studies on the stimulation of growth by dietary antibiotics. Poultry Sci. 42: Rickes, E. L., E. A. Ham, E. A. Moscatelli and W. H. Ott, The isolation and properties of (5-glucanase from B. subtilis. Arch. Biochem. Biophys. 69: Vohra, P. and F. H. Kratzer, Growth inhibitory effect of certain polysaccharides for chickens. Poultry Sci. 43: THE absorption of dietary calcium and phosphorus by the chick depends on a number of factors. Adequate solubility of compounds of these minerals, as indeed of other essential elements, is a primary requisite but co-factors of absorption may also play an important role in the efficient utilization of these nutrients. Hill et al. (1945) determined the solubilities of a variety of phosphates in several solvents and showed that soft phosphate was not as readily soluble as bone meal and tricalcium phosphate. On the basis of these solubility tests, it can be surmised that the relatively low growth and bone calcification often observed in birds fed soft phosphate (as reviewed by Motzok et al., 1956; and Almquist, 1962) may be due at least in part to the low solubility of this type of supplement. On the other hand, the importance of vitamin D as a co-factor in the 1 Now Dean of Graduate Studies, University of Guelph, Guelph, Ontario. Waibel, P. E., O. J. Abbott, C. A. Bowman and H. R. Bird, Disappearance of the growth response of chicks to dietary antibiotics in an "old" environment. Poultry Sci. 33: Willingham, H. E., L. S. Jensen and J. McGinnis, Studies on the role of enzyme supplements and water treatment for improving the nutritional value of barley. Poultry Sci. 38: Willingham, H. E., K. C. Leong, L. S. Jensen and J. McGinnis, Influence of geographical area of production on response of different barley samples to enzyme supplements or water treatment. Poultry Sci. 39: Factors Affecting the Utilization of Calcium and Phosphorus From Soft Phosphate by Chicks I. MOTZOK, D. ARTHUR AND H. D. BRANION 1 Department of Nutrition, Ontario Agricultural College, University of Guelph, Guelph, Canada (Received for publication March 18, 1965) absorption of dietary calcium has been clearly established (Wasserman, 1963). Furthermore, Nicolaysen (1937) and Harrison and Harrison (1961) using in vivo and in vitro techniques, observed that vitamin D enhanced the uptake of phosphate by the intestine of rats when calcium was given concurrently. Thus the increased absorption of calcium in vitamin D-treated animals appeared to promote an increase in the removal of phosphate as a secondary effect. Although the importance of vitamin D in the intestinal absorption of calcium has been recognized for a number of years, no intensive study has been reported in the literature of the possibility than an abundance of vitamin D in the diet of fowl above the amount (90 I.C.U./lb.) recommended by the National Research Council (1960), would improve the utilization of calcium and phosphorus from supplements of relatively low solubility. The present experiments were designed