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The Utilization of Phytate Phosphorus by Poultry—A Review
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J. O. ANDERSON AND R. E.
Ousterhout, L. E., 1960. Survival time and biochemical changes in chicks fed diets lacking different essential amino acids. J. Nutrition, 70: 226-234. Sanders, B. G., S. O. Brown and J. R. Couch, 1950. A feathering syndrome in chicks after feeding optimal levels of lysine in the absence
WAENICK
of arginine. Proc. Soc. Exp. Biol. Med. 74: 114— 117. Wilkening, M. C , B. S. Schweigert, P. B. Pearson and R. M. Sherwood, 1947. Studies on the requirement of the chick for tryptophan. J. Nutrition, 34: 701-714.
T. S. N E L S O N
Research and Development Division, International Minerals and Chemical Libertyville, Illinois 60048
Corporation,
(Received for publication November 8, 1966)
T
HE metabolism of phosphorus derived from plant tissues is one of the least understood and most debated subjects in the field of mineral nutrition. A small proportion of the total phosphorus in plants is inorganic phosphates located primarily in the vegetative tissues. Most of the phosphorus is in a variety of organic compounds found primarily in the seed, and phytate phosphorus is the predominant organic form. The amount of phytate phosphorus utilized by animals has economic importance because seeds are the major plant-source ingredients used in feeds. Many scientists currently use the rule that monogastric animals metabolize only one-third of the phosphorus in plant materials. This assumption is based on the report by the Committee on Animal Nutrition, National Academy of Sciences-National Research Council (NAS-NRC) (1960) that approximately 30% of the phosphorus in plant materials in non-phytate and can be considered to be utilized by animals. Many scientists using a variety of experimental procedures have studied the ability of different species of animals to utilize phytate phosphorus. However, they have failed to define to everyone's satisfaction
the extent of phytate phosphorus availability in strictly quantitative terms. Certain authors have reported it was utilized to a limited extent. Others have considered it was highly available to animals. Kastelic and Forbes (1961) and Taylor (1965) reviewed this subject. They stressed that there is still no general agreement on the extent to which different species of animals at various ages utilize phytate phosphorus. Studies of Phytate Phosphorus Utilization Heuser et al. (1943), McGinnis et al. (1944), Singsen et al. (1947), Gillis et al. (1949), and Sunde and Bird (1956) observed that natural phytate was a poor source of phosphorus for various species of poultry. Conversely, Sieburth et al. (1952) reported the phosphorus in finely ground whole wheat flour was almost completely available to chicks for growth but was less available than inorganic phosphate for bone deposition. Temperton et al. (1965a, b, c) concluded that pullet chicks less than four weeks old, growing pullets reared to 18 weeks of age and laying hens were able to achieve effective utilization of organic sources of phosphorus for growth and bone formation. Several investigators have fed various
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The Utilization of Phytate Phosphorus by Poultry—A Review
UTILIZATION OF PHYTATE PHOSPHORUS
Few investigators have studied the quantitative utilization of phytate phosphorus by poultry. Gillis et al. (1953) reported White Leghorn hens utilized phytate phosphorus approximately one-half as effectively as the phosphorus in dicalcium phosphate. Gillis et al. (1957) fed chicks and turkeys P 32 labeled calcium phytate and P 32 labeled monosodium ortho phosphate and then measured the amount of radioactivity retained in the tibia. They concluded that chicks utilized the phosphorus in calcium phytate only 10% as effectively as that in monosodium ortho phosphate and that the relative utilization of calcium phytate phosphorus by the turkey was less than 2%. The availability of phytate phosphorus has also been studied in phosphorus balance trials. Nikolaiczuk (1950) reported that chicks retained 14% to 18% of the phytate phosphorus in the dietary ingredients. Not all of the phytate phosphorus was recovered in the feces and the author concluded that degradation processes other than hydrolysis accounted for this unrecovered phytate. Ashton et al. (1960) fed P 32 labeled calcium phytate and observed that chicks four-weeks old retained approxi-
mately 20% of the phytate phosphorus whereas six-week old chicks retained 36% to 49% of this phosphorus. They concluded the chicks utilized one-fifth of the phytate phosphorus. Temperton and Cassidy (1964)reported chicks retained approximately 60% of the phytate phosphorus and only 50% of the non-phytate phosphorus. They indicated that the chick's total need for phosphorus could be met with plantsource phosphorus. It is apparent that wide disagreement has existed between investigators on the ability of the chick to utilize phytate phosphorus. Varied experimental methods and materials were used and may have contributed to this disagreement. These variables included the source of phytate phosphorus, criteria of response, age of the test animals, and calcium and vitamin D 3 levels in the experimental diets. Sources of Phytate Tested The sources of the phytates tested may have caused some of the discrepancies between reports on phytate phosphorus utilization by poultry. Phytate phosphorus occurs in plants as the mixed calcium-magnesium-potassium salt of phytic acid (Anderson, 1915c; Averill and King, 1926). The availability of this "natural" phytate phosphorus may differ from that in a chemically isolated fraction for at least two reasons. The first is the fact that phytic acid-protein complexes are formed in certain types of processed seed meals that reduce the solubility of these proteins (Fontaine et al., 1946). Such complexes may also cause further reduction in the availability of the phytate phosphorus by delaying the onset of enzymatic attack during the digestive process. Another reason is the source of the natural phytate phosphorus may influence its availability to the animal. Some feed ingredients contain the enzyme phytase which hydrolyzes phytate to phosphoric
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phytates as the isolated but impure chemical compound rather than relying on feed ingredients as the source. Lowe et al. (1939) reported that chicks did not efficiently utilize phytate phosphorus isolated from wheat bran. Singsen and Mitchell (1945) and Matterson et al. (1946) found calcium magnesium phytate was a poor source of phosphorus for the turkey poult. Gillis et al. (1948) showed that chicks were unable to utilize relatively pure calcium phytate. Waldroup et al. (1964a) reported the availability of the phosphorus in calcium phytate and sodium phytate was less than that of sodium phosphate. Harms et al. (1962) and Waldroup et al. (1964a) concluded that the phosphorus in phytic acid was highly available to the chick.
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dium phytate and phytic acid are more soluble and should be partially hydrolyzed to phosphoric acid which can be utilized by the chick. Accordingly, one cannot extrapolate the availability of the phosphorus in sodium phytate or phytic acid to naturally occurring phytate phosphorus. Criteria of Response Percent bone ash and weight gain have been the most common criteria used to study the utilization of phytate phosphorus. P 32 deposition from labeled phytate and phosphorus balance studies have been used to a lesser extent. The percent of bone ash is one of the most sensitive practical criteria for evaluating the availability of dietary phosphorus. It is more accurate than body weight (Nelson and Walker, 1964; Dilworth, 1966) and is little affected by other dietary variables that influence growth. Body weight gain is not an accurate measure of phosphorus utilization and its use has led to misleading conclusions. Singsen et al. (1947) and Sieburth et al. (1952) reported phytate phosphorus was more available for growth than for bone calcification. Vanderpopuliere et al. (1961) concluded plant-source phosphorus was readily available to support growth but that it would not increase the percent bone ash when the calcium:phosphorus ratio was narrowed from 4:1 to 1:1. Waldroup et al. (1964a), in an opposing view, reported calcium phytate phosphorus was more available for bone deposition than for growth. A more realistic view was expressed by Taylor (1965), commenting on the theory that the animal can partition phytate phosphorus between growth and bone calcification: "If it is agreed that the P of phytate is in all probability absorbed as phosphate ions, the concept of a greater or lesser 'availability' for a particular physiological function becomes quite unacceptable." Nelson et al. (1965) published data sup-
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acid (Anderson, 1915a, b). Wheat, rye and barley are high in phytase activity whereas oats, maize and various seed meals contain little or none of the enzyme (McCance and Widdowson, 1944; Mollgaard, 1946). Therefore, phytate phosphorus should be more available in ingredients containing this enzyme or in diets containing ingredients with a high phytase content. Chemical forms of phytate appear to offer both advantages and disadvantages for phosphorus assay purposes. These compounds are not bound as the protein complex and presumably should give a more reliable estimate of phytate phosphorus utilization per se. It would appear that compounds such as magnesium phytate are the most desirable compounds to test since they are similar in composition to natural phytate. However, neither is the same compound that existed in the plant. Calcium phytate and calcium magnesium phytate were tested in the work cited above. They were found to be a poor source of phosphorus, which suggested that natural phytate was also poorly utilized. Sodium phytate and phytic acid were other chemical phytates tested in the work cited above. Both were reported to be better sources of phosphorus than calcium phytate. However, neither was the form found in the plant. Therefore, for reasons mentioned below, they cannot be used to determine phytate phosphorus utilization. The purity and solubility of any phytate compound may influence the apparent availability of the phosphorus. Analyses in this laboratory have shown that calcium phytate, sodium phytate, and phytic acid were contaminated with ortho phosphate. This form of phosphorus would be metabolized by the animal and could lead to errors in estimating the utilization of phytate phosphorus. Calcium phytate is insoluble and is relatively inert to acid or basic hydrolysis in the pH ranges that exist in the digestive tract of poultry. Conversely, so-
UTILIZATION OF PHYTATE PHOSPHORUS
bone calcification. They explained that the exchange reaction probably was the mechanism observed, and if true, the phytate molecule removed as much phosphorus from the body as it brought in. This agreed with Common's belief that the intact phytate molecule was excreted in the feces. The exchange reaction is the simple chemical exchange of the same element between two different compounds. The exchange of P 32 from phytate with P from an inorganic source would render the P 32 available. It would appear, based on radioactivity measurements, that phytate phosphorus is utilized. However, if it is replaced with inorganic P which is rendered unavailable when incorporated into the phytate molecule, there is no net utilization of phytate phosphorus. Gillis et al. (1957) used P 32 labeled calcium phytate and P 32 labeled monosodium ortho phosphate to study phytate phosphorus utilization. Their conclusions, discussed above, were based on the amount of P 32 retained in the tibia. They also demonstrated that P 32 from NaH 2 P 32 0 4 exchanged readily with the phosphorus from calcium phytate in vitro. This agreed with the theory Singsen et al. (1950) used to explain the apparent utilization of phytate phosphorus by poults. The work of Gillis et al. (1957) emphasized the fact that the recovery of radioactivity in the body does not necessarily represent a net utilization of phytate phosphorus. It is possible for the net utilization to be zero because of the exchange reaction. The effect of age on the ability of poultry to utilize phytate phosphorus has not been clearly defined. The data available suggest that the utilization of phytate phosphorus increases with increasing age to maturity. The degree to which this is true, however, has not been established, primarily because of the types of experimental diets used. McGinnis et al. (1944) compared the
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porting this statement and explaining the differences observed between growth and bone deposition. Chicks were fed purified diets practically devoid of calcium and phosphorus. These diets were supplemented with inorganic sources of calcium and phosphorus at ratios of 4:1 and 2:1. The chicks gained weight when the calcium content of these diets was reduced to narrow the ratio. However, the source of supplemental phosphorus determined whether or not the percent bone ash increased as the calcium content of the diet was decreased. These data, obtained in the absence of phytate phosphorus, were similiar to those of Singsen et al. (1947), Sieburth et al. (1952) and Vanderpopuliere et al. (1961) who reported the possible partition of phytate phosphorus between growth and bone deposition. It is probable that the improved weight gain they observed was a response to a more favorable calcium level rather than a peculiar partition in the utilization of phytate phosphorus. If this assumption is true, then the availability of phytate phosphorus in finely ground whole wheat flour was less than indicated by Sieburth et al. (1952). Common (1939) reported the phytate was inactive in the body of the chick and the poult and passed out in the feces as the intact molecule. Singsen et al. (1950) concluded the phosphorus in the phytate molecule moved quickly and easily throughout the body of the turkey poult. Although these authors disagreed on the metabolism of the phytate molecule, they did agree on the probable availability of the phosphorus. Singsen's group fed poults P 32 labeled calcium phytate and found radioactivity in the blood, down and muscle tissue within one hour after dosing. They stated it was unlikely that the low phytase activity in the intestine would hydrolyze P 32 from the phytate molecule so rapidly. Although P32 was deposited in the bone salts, the unlabeled phytate phosphorus did not support
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Calcium phytate contains approximately
Reports have been published suggesting
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utilization of the phosphorus in a natural equal amounts of calcium and phosphorus. diet by chicks to four and eight weeks of Plant phytate is the mixed calcium magneage. The chicks had a higher percentage of sium potassium salt of phytic acid and bone ash at eight weeks. This could have therefore contains less calcium than phosbeen the result of either increased utiliza- phorus. The availability of phytate calcium tion of phytate phosphorus or a reduced has not been established and it is presumphosphorus requirement. Gillis et al. ably possible, based on the work cited (1953, 1957) observed differences in the above, that little of it is available. Furtherability of the chick and the hen to utilize more, it is also presumably possible for the phytate phosphorus. The hen diet con- phytate molecule to inactivate a portion of tained wheat bran, which probably con- the supplemental calcium in the digestive tained the enzyme phytase. Conceivably, tract. Theoretically, this could occur bepart or all of the increased ability of the cause of the low calcium-phosphorus ratio hen to utilize phytate phosphorus could of plant phytate compared to calcium phytate. have been due to wheat bran phytase. Another role of calcium on apparent Ashton et al. (1960) found differences in phytate phosphorus retention of four-week availability of phytate phosphorus concerns and six-week old chicks fed the same diets. the dietary levels fed in relation to the Temperton et al. (1965a, b, c) reported available phosphorus. This was discussed that pullets and laying hens could utilize above, but it should be reemphasized that organic sources of phosphorus. However, at it is fallacy to conclude that responses obleast three ingredients in their diets proba- tained by changing dietary calcium levels result from changes in the availability of bly contained high phytase activity. Therefore, while older poultry may utilize phytate phosphorus. phytate phosphorus more efficiently than younger birds, the use of feed ingredients Vitamin D The effect of vitamin D on phosphorus that contained phytase activity in some experiments may have overemphasized this utilization has received renewed attention in recent years. The primary function of age difference. this vitamin, demonstrated by Nicolaysen Calcium. et al. (1953) and by Keane et al. (1956) is to promote calcium absorption. This proCalcium has been shown to have an adcess is an active one which proceeds against verse effect on the availibility of phytate an electrochemical gradient (Wasserman et phosphorus. Conversely, the phytate moleal, 1961). Nicolaysen et al. (1953) concule has been observed to reduce the availcluded that the increased phosphorus ability of calcium. Phytate supplied either by dietary ingredients or in a chemical absorption they observed was secondary to form reduced calcium absorption from the the calcium absorption. Their work reintestine of humans (McCance and Wid- ceived the support of Harrison and Harridowson, 1942a, b; Krebs and Mellanby, son (1961) who concluded that phosphate 1943; Bronner et al, (1954). Hoff-Jorgen- transport was dependent of calcium. Acsen (1946) and Mellanby (1949) observed cording to Rasmussen and DeLuca (1963), a similar effect in dogs. Melanby attributed the only regulation of phosphate absorption this to the precipitation of insoluble penta- by vitamin D is indirectly through changes in calcium absorption. calcium phytate.
UTILIZATION OF PHYTATE PHOSPHORUS
ferentiate between the response to vitamin D 3 because of the imbalanced calciumavailable phosphorus ratio and in enhancing phytate phosphorus utilization. With both of these actions occurring simultaneously, the results could overemphasize the value of vitamin D 3 for improving phytate phosphorus utilization. A second theory suggested that vitamin D increased the production of phytase in the intestine or that it enhanced the activity of the phytase contained in the feed ingredients. The report by Spitzer et al. (1948) does not agree with this theory. They were unable to increase the intestinal phytase activity by adding vitamin D to tissue homogenates. Pileggi et al. (1955) published evidence to support this theory. They reported that vitamin D increased the intestinal phytase activity two to five times in the intact animal. Roberts and Yudkin (1961) also found that this vitamin increased phytase activity in rats. However, this theory has not been investigated fully to determine its merits.
At least two theories have been put forth to explain the mode of action of vitamin D 3 . Singsen et al. (1950) suggested that phytate phosphorus was labile, but in the absence of this vitamin the phytate molecule probably removed as much phosphorus from the body as it brought in. However, under the influence of vitamin D 3 another Phytase Enzyme radical replaced part of the phytate phosThe presence of the enzyme phytase in phorus which then became available to the certain feed ingredients and its possible seanimal. The improved phosphorus utiliza- cretion in the intestine were discussed eartion in the presence of vitamin D 3 repre- lier in this review. Additional information sented this released phytate phosphorus, on the action of phytase was reported by rather than the increased utilization of the Courtois (1945) and by Courtois and Masnon-phytate phosphorus. son (1950). Plant phytase was specific for The effect of vitamin D 3 in increasing phytate phosphorus and cleaved phosphate the utilization of the inorganic phosphorus from alternate rather than adjacent carbon cannot be totally discounted, however. It is atoms. Sandegren (1948) and Mattson and well documented that, at an optimum calci- Koutler-Andersson (1947) indicated that um to available phosphorus ratio, little, if this enzyme was active in a narrow pH any, response is obtained from vitamin D 3 . range. Proteins precipitated phytate on the Conversely, a response can be obtained if acid side, but it was precipitated by calcithe ratio is unbalanced. Vitamin D 3 re- um and magnesium ions in an alkaline consponses were obtained in most of the exper- dition. Plant phytase can hydrolyze phyiments cited above with diets containing tate phosphorus, and the conditions for its imbalanced levels of calcium and available action suggest that the enzyme would be phosphorus. It was impossible to dif- active in the digestive tract of animals.
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that vitamin D 3 improved the utilization of phytate phosphorus. Lowe et al. (1939), Singsen and Mitchell (194S) and Singsen et al. (1947) increased the bone ash in chicks and poults by feeding higher levels of vitamin D 3 . McGinnis et al. (1944) reported chicks responded to increased levels of vitamin D 3 in a manner suggesting better utilization of phytate phosphorus. Gillis et al. (1949) observed that high levels of vitamin D 3 improved the performance of chicks fed either calcium phytate or natural phytate phosphorus. Gillis et al. (1957) found that vitamin D 3 caused a small increase in the retention of phytate P 32 in the bones. Waldroup et al. (1964b) increased the weights of the chicks fed either calcium phytate or dicalcium phosphate by increasing the vitamin D 3 content of the diet.
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Singsen and Mitchell (1944) studied the middlings. These two ingredients supposedeffect of feeding an ingredient with an ap- ly contained phytase activity. The difparent high phytase activity. The addition ference between their results and those of sun-cured alfalfa meal, which presum- of Singsen and Mitchell (1944) and Temably contained phytase activity, to a chick perton et al. (1965a, b, c) suggests that diet promoted weight gain and bone ash as plant-source feed ingredients either vary in well as supplemental inorganic phosphate their original phytase content or that the whereas dehydrated alfalfa meal was enzyme was labile under the handling conineffective. They concluded that the sun- ditions of the feed ingredients. It appears cured sample contained phytase activity that specific feed ingredients cannot be that was apparently destroyed in the dehy- considered to be a consistent source of phydrated sample. If their conclusion was cor- tase. rect, then it appears that the enzyme also Curtois and Valentino (1947) found that hydrolyzed the phytate phosphorus con- purified phytase, extracted from wheat tained in the other feed ingredients. Tem- bran, was ineffective in the rat. The perton et al. (1965a, b, c) presented indi- difference between their results and those rect evidence that plant phytase was effec- of Warden and Schaible (1962) may have tive in feeds. Their diets contained 32 to reflected differences in phytase enzymes 36% wheat and 10% barley meal which from plant and bacterial sources. have been reported to be sources of phytase. These diets also contained three per- Plant Phosphorus cent grass meal which may have been Common (1940) reported the phytic similar to the sun-cured alfalfa meal acid phosphorus content of feedstuffs destudied by Singsen and Mitchell (1944). rived from processed oil seeds, including Warden and Schaible (1962) appear to soya bean meal, was one-half to two-thirds have established that bacterial phytase can of the total phosphorus. Phytic acid phosbe active in the digestive tract. They found phorus accounted for two-thirds to threethe addition of lysed E. coli cellular mate- fourths of the total phosphorus in cereal rial to the diet improved both growth and grains. bone development and suggested this was a Mollgaard (1946) showed slightly response to phytase or similar enzymes. higher concentrations of phytate phosphoIt appears, in view of these reports, that rus in processed oil seeds (70-80%) and some of the differences observed in the in cereal grains (65-85%). ability of the various species of poultry to The non-phytate phosphorus content of utilize phytate phosphorus can be ex- those ingredients mentioned above ranged plained by the presence or absence of phy- from 15-50%. The degree to which this is tase in the experimental diets. utilized by the animal has not been clearly Although the work cited above suggests established. It is questionable, from the phytase activity can be a determining fac- data available, whether any portion of the tor in phytate phosphorus utilization, the phytate phosphorus should be considered conditions for its activity have not been available. Rations formulated with one part clearly established. McGinnis et al. (1944) plant protein source for each two parts found chicks made inefficient use of phy- plant energy source will contain approxitate phosphorus in a diet that contained mately 30% non-phytate phosphorus. Con20% wheat bran and 10% wheat flour sidering this to be available, phosphorus
UTILIZATION OF PHYTATE PHOSPHORUS
Conclusions The preponderance of data suggests that phosphorus is absorbed as the inorganic phosphate ion. Therefore, the ability of the various species of poultry to utilize phytin phosphorus will depend, in the simplest terms, on their ability to liberate phosphate ions from the phytate molecule by hydrolysis. There is no evidence showing unquestionable proof that phytate is absorbed and utilized intact by any animal species. Present knowledge of calcium and phosphorus utilization and the role of vitamin D 3 permits tentative conclusions on the various species of poultry to utilize phytin phosphorus. 1. In order to be utilized, phytin phosphorus must be hydrolyzed to yield inorganic phosphate. 2. The chick absorbs and utilizes dietary phosphorus without regard to its organic or inorganic origin. The chick cannot partition the phosphorus derived from the phytate molecule between different metabolic functions in a manner different from that derived from inorganic sources. 3. Young birds have very limited ability to hydrolyze phytin phosphorus. This abili-
ty increases with age up to maturity; however, the magnitude of this increase has not been accurately quantified. 4. Calcium, at levels required by poultry, has an adverse effect upon the utilization of phytin phosphorus. The availability of phytate calcium has not been established. 5. Vitamin D 3 probably enhances the utilization of phytate phosphorus by animals to a limited extent. However, the magnitude of this increase is small and appears to be dependent upon several other dietary interrelationships. 6. Phytase enzyme, present in certain feed ingredients and possibly secreted by the intestine, hydrolizes phytate phosphorus to a form that can be utilized. Under certain conditions this enzyme will hydrolyze dietary phytate phosphorus making it available to the animal. This appears to be the most effective force at work in the digestive tract that results in utilizaion of phytate phosphorus. 7. The National Academy of SciencesNational Research Council's recommendation that 30% of the total plant phosphorus is available to animals can usually be applied to a mixture of ingredients but not to individual ingredients. REFERENCES Anderson, R. J., 1915a. The hydrolysis of phytin by the enzyme phytase contained in wheat bran. J. Biol. Chem. 20:475-482. Anderson, R. J., 1915b. The hydrolysis of the organic phosphorus compound of wheat bran by the enzyme phytase. J. Biol. Chem. 20: 483491. Anderson, R. J., 1915c. Concerning phytin in wheat bran. J. Biol. Chem. 20: 493-500. Ashton, W. M., C. Evans and P. C. Williams, 1960. Phosphorus compounds of oats. II. The utilisation of phytate phosphorus by growing chicks. J. Sci. Food Agric. 11: 722-727. Averill, H. P., and C. G. King, 1926. The phytin content of foodstuffs. J. Am. Chem. Soc. 48: 724-728.
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would agree with the NAS-NRC recommendation that 30% of the plant phosphorus is available to the animal. The NAS-NRC recommendation does not consider (a) variations in the phytate content of different ingredients, (b) the availability of the non-phytate phosphorus, and (c) the possible utilization of some of the phytate phosphorus. In view of the fact that animals can utilize some portion of the plant phosphorus, and based upon the discussion above, the NAS-NRC recommendation appears to be a close estimate of the available phosphorus in a mixture of plant materials but not for individual ingredients.
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T. S. NELSON acid on the absorption of calcium and phosphorus. 1. In dogs. Biochem. J. 40: 189-192. Kastelic, J., and R. M. Forbes, 1961. Animal nutrition and phosphates in feeds. The availability of phosphorus in plant materials to various species of animals. Chapt. 24, pp. 1549-1561, Phosphorus and its Compounds, Vol. II, J. R. Van Wazer, Ed. Interscience Publishers, Inc., N. Y. Keane, K. W., R. A. Collins and M. B. Gillis, 1956. Isotopic tracer studies on the effect of vitamin D on calcium metabolism in the chick. Poultry Sci. 35: 1216-1222. Krebs, H. A., and K. Mellanby, 1943. The effect of national wheatmeal on the absorption of calcium. Biochem. J. 37: 466-468. Lowe, J. T., H. Steenbock and C. H. Krieger, 1939. Cereals and rickets. IX. The availability of phytin-P to the chick. Poultry Sci. 18: 4044. Matterson, L. D., H. M. Scott and E. P. Singsen, 1946. The influence of sources of phosphorus on the relative efficiency of vitamin D 3 and cod liver oil in promoting calcification in poults. J. Nutr. 3 1 : 599-608. Mattson, S., and E. Koutler-Andersson, 1947. The acid-base condition in vegetation, litter and humus. X. Some properties and functions of phytin. Kgl. Lantbruks-Hogskol. Ann. 14: 290-300. McCance, R. A., and E. M. Widdowson, 1942a. Mineral metabolism of healthy adults on white and brown bread dietaries. J. Physiol. 101: 44-85. McCance, R. A., and E. M. Widdowson, 1942b. Mineral metabolism on dephytinized bread. J. Physiol. 101: 304-313. McCance, R. A., and E. M. Widdowson, 1944. Activity of the phytase in different cereals ana its resistance to dry heat. Nature, 153 : 650. McGinnis, J., L. C. Norris and G. F. Heuser, 1944. Poor utilization of phosphorus in cereals and legumes by chicks for bone development. Poultry Sci. 23 : 157-159. Mellanby, E., 1949. Rickets—producing and anticalcifying action of phytate. J. Physiol. 109: 488-533. Mollgaard, H., 1946. On phytic acid, its importance in metabolism and its enzymic cleavage in bread supplemented with calcium. Biochem. J. 40: 589-603. National Academy of Sciences-National Research Council, 1960. Nutrient requirements for domestic animals. 1. Nutrient requirements for poultry.
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on February 22, 2015
Bronner, F., R. S. Harris, C. J. Maletskos and C. E. Benda, 1954. Studies in calcium metabolism. Effect of food phytates on calcium45 uptake in children on low-calcium breakfasts. J. Nutr. 54: 523-542. Common, R. H., 1939. Phytic acid in mineral metabolism in poultry. Nature, 143: 379-380. Common, R. H., 1940. The phytic acid content of some poultry feeding stuffs. The Analyst, 65: 79-83. Courtois, J., 1945. Phytase. I. Comparative action of various enzyme preparations on inositol hexaphosphate and sodium glyceralphosphate. Bull. Soc. Chim. Biol. 27: 411-415. Courtois, J., and M. Masson, 1950. Phytase XVI. Compounds obtained after partial hydrolysis of phytin. Bull. Soc. Chim. Biol. 32: 326-332. Courtois, J., and A. Valentino, 1947. Phytase IV. Does the ingestion of phytase favor the absorption of inositol phosphates? Bull. Soc. Chim. Biol. 29:615-620. Dilworth, B. C , 1966. A study of certain factors affecting the utilization of calcium and phosphorus by the chick. Ph.D. Thesis. Mississippi State University, State College. Fontaine, T. D., W. A. Pons, Jr. and G. W. Irving, Jr., 1946. Protein-phytic acid relationship in peanuts and cottonseed. J. Biol. Chem. 164: 487-507. Gillis, M. B., K. W. Keane and R. A. Collins, 1957. Comparative metabolism of phytate and inorganic P32 by chicks and poults. J. Nutr. 62: 13-26. Gillis, M. B., L. C. Norris and G. F. Heuser, 1948. The utilization by the chick of phosphorus from different sources. J. Nutr. 35:195-207. Gillis, M. B., L. C. Norris and G. F. Heuser, 1949. The effect of phytin on the phosphorus requirement of the chick. Poultry Sci. 28: 283-288. Gillis, M. B., L. C. Norris and G. F. Heuser, 1953. Phosphorus metabolism and requirements of hens. Poultry Sci. 32 : 977-984. Harms, R. H., P. W. Waldroup, R. L. Shirley and C. B. Ammerman, 1962. Availability of phytic acid phosphorus for chicks. Poultry Sci. 4 1 : 1189-1191. Harrison, H. E., and H. C. Harrison, 1961. Intestinal transport of phosphate: action of vitamin D, calcium and potassium. Am. J. Physiol. 201: 1007-1012. Heuser, G. F., L. C. Norris, J. McGinms and M. L. Scott, 1943. Further evidence of the need for supplementing soybean meal chick rations with phosphorus. Poultry Sci. 22: 269-270. Hoff-Jorgensen, E., 1946. The influence of phytic
UTILIZATION OF PHYTATE PHOSPHORUS
185-193. Sunde, M. L., and H. R. Bird, 1956. A critical need of phosphorus for the young pheasant. Poultry Sci. 35: 424-430. Taylor, T. G., 1965. The availability of the calcium and phosphorus of plant materials for animals. Proc. Nutr. Soc. 24: 105-112. Temperton, H., and J. Cassidy, 1964. Phosphorus requirements of poultry. I. The utilization of phytin phosphorus by the chick as indicated by balance experiments. Br. Poultry Sci. S: 7580. Temperton, H., F. J. Dudley and G. J. Pickering, 1965a. Phosphorus requirements of poultry. IV. The effects on growing pullets of feeding diets containing no animal protein or supplementary phosphorus. Br. Poultry Sci. 6: 125133. Temperton, H., F. J. Dudley and G. J. Pickering, 1965b. Phosphorus requirements of poultry. V. The effects during the subsequent laying year of feeding growing diets containing no animal protein or supplementary phosphorus. Br. Poultry Sci. 6: 135-141. Temperton, H., F. J. Dudley and G. J. Pickering, 1965c. Phosphorus requirements of poultry. VI. The phosphorus requirements of growing pullets between 8 and 18 weeks of age. Br. Poultry Sci. 6:143-151. Vanderpopuliere, J. M., C. B. Ammerman and R. H. Harms, 1961. The relationship of calciumphosphorus ratios to the utilization of plant and inorganic phosphorus by the chick. Poultry Sci. 40: 951-957. Waldroup, P. W., C. B. Ammerman and R. H. Harms, 1964a. The availability of phytic acid phosphorus for chicks. 2. Comparison of phytin phosphorus sources. Poultry Sci. 4 3 : 426432. Waldroup, P. W., C. B. Ammerman and R. H. Harms, 1964b. The availability of phytic acid phosphorus for chicks. 3. Effect of calcium and vitamin D 3 levels on the utilization of calcium phytate. Poultry Sci. 43: 926-931. Warden, W. K., and P. J. Schaible, 1962. Action of antibiotics in stimulating growth of poultry. 1. Effect of E. coli and fecal preparations. Poultry Sci. 4 1 : 725-732. Wasserman, R. H., F. A. Kallfelz and C. L. Comar, 1961. Active transport of calcium by rat duodenum in vivo. Science, 133 : 883-884.
AUGUST 21-25, FIFTY-FIFTH ANNUAL MEETING OF THE POULTRY SCIENCE ASSOCIATION, UNIVERSITY OF NEW HAMPSHIRE, DURHAM, N.H.
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Nelson, T. S., W. A. Hargus, N. Storer and A. C. Walker, 1965. The influence of calcium on phosphorus utilization by chicks. Poultry Sci. 44: 1508-1513. Nelson, T. S., and A. C. Walker, 1964. The biological evaluation of phosphorus compounds. A summary. Poultry Sci. 43 : 94-98. Nicolaysen, R., N. Eeg-Larsen and O. J. Malm, 1953. Physiology of calcium metabolism. Physiol. Revs. 33:424-444. Nikolaiczuk, N., 1950. The availability and retention of phosphorus from organic and inorganic sources by the chick. Abs. of Doctoral Diss., Ohio St. U. Press. Pileggi, V. J., H. F. DeLuca and H. Steenbock, 1955. The role of vitamin D and intestinal phytase in the prevention of rickets in rats on cereal diets. Arch. Biochem. Biophys. 58: 194204. Rasmussen, H., and H. F. DeLuca, 1963. Calcium homeostasis. Ergebn. Physiol. 53: 108-173. Roberts, A. H., and J. Yudkin, 1961. Effect of phytate and other dietary factors on intestinal phytase and bone calcification in the rat. Brit. J. Nutr. 15:457-471. Sandegren, E., 1948. Barley phytin in malting and brewing. J. Inst. Brewing, 54: 200-207. Sieburth, J. F., J. McGinnis, T. Wahl and B. A. McLaren, 1952. The availability of the phosphorus in unifine flour for the chick. Poultry Sci. 3 1 : 813-818. Singsen, E. P., L. D. Matterson and A. Kozeff, 1950. Phosphorus in poultry nutrition. IV. Radioactive phosphorus as a tracer in studying the metabolism of phytin by the turkey poult. Poultry Sci. 29: 635-639. Singsen, E. P., L. D. Matterson and H. M. Scott, 1947. Phosphorus in poultry nutrition. III. The relationship betw:en the source of vitamin D and the utilization of cereal phosphorus by the poult. J. Nutr. 33 : 13-26. Singsen, E. P., and H. H. Mitchell, 1944. Soybean meal chick rations need no inorganic phosphorus supplements. Poultry Sci. 23 : 152-153. Singsen, E. P., and H. H. Mitchell, 1945. Phosphorus in poultry nutrition. I. The relation between phytin and different sources of vitamin D. Poultry Sci. 24: 479-480. Spitzer, R. R., G. Maruyama, L. Michaud and P. H. Phillips, 1948. The role of vitamin D in the utilization of phytin phosphorus. J. Nutr. 35:
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Ousterhout, L. E., 1960. Survival time and biochemical changes in chicks fed diets lacking different essential amino acids. J. Nutrition, 70: 226-234. Sanders, B. G., S. O. Brown and J. R. Couch, 1950. A feathering syndrome in chicks after feeding optimal levels of lysine in the absence
WAENICK
of arginine. Proc. Soc. Exp. Biol. Med. 74: 114— 117. Wilkening, M. C , B. S. Schweigert, P. B. Pearson and R. M. Sherwood, 1947. Studies on the requirement of the chick for tryptophan. J. Nutrition, 34: 701-714.
T. S. N E L S O N
Research and Development Division, International Minerals and Chemical Libertyville, Illinois 60048
Corporation,
(Received for publication November 8, 1966)
T
HE metabolism of phosphorus derived from plant tissues is one of the least understood and most debated subjects in the field of mineral nutrition. A small proportion of the total phosphorus in plants is inorganic phosphates located primarily in the vegetative tissues. Most of the phosphorus is in a variety of organic compounds found primarily in the seed, and phytate phosphorus is the predominant organic form. The amount of phytate phosphorus utilized by animals has economic importance because seeds are the major plant-source ingredients used in feeds. Many scientists currently use the rule that monogastric animals metabolize only one-third of the phosphorus in plant materials. This assumption is based on the report by the Committee on Animal Nutrition, National Academy of Sciences-National Research Council (NAS-NRC) (1960) that approximately 30% of the phosphorus in plant materials in non-phytate and can be considered to be utilized by animals. Many scientists using a variety of experimental procedures have studied the ability of different species of animals to utilize phytate phosphorus. However, they have failed to define to everyone's satisfaction
the extent of phytate phosphorus availability in strictly quantitative terms. Certain authors have reported it was utilized to a limited extent. Others have considered it was highly available to animals. Kastelic and Forbes (1961) and Taylor (1965) reviewed this subject. They stressed that there is still no general agreement on the extent to which different species of animals at various ages utilize phytate phosphorus. Studies of Phytate Phosphorus Utilization Heuser et al. (1943), McGinnis et al. (1944), Singsen et al. (1947), Gillis et al. (1949), and Sunde and Bird (1956) observed that natural phytate was a poor source of phosphorus for various species of poultry. Conversely, Sieburth et al. (1952) reported the phosphorus in finely ground whole wheat flour was almost completely available to chicks for growth but was less available than inorganic phosphate for bone deposition. Temperton et al. (1965a, b, c) concluded that pullet chicks less than four weeks old, growing pullets reared to 18 weeks of age and laying hens were able to achieve effective utilization of organic sources of phosphorus for growth and bone formation. Several investigators have fed various
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The Utilization of Phytate Phosphorus by Poultry—A Review
UTILIZATION OF PHYTATE PHOSPHORUS
Few investigators have studied the quantitative utilization of phytate phosphorus by poultry. Gillis et al. (1953) reported White Leghorn hens utilized phytate phosphorus approximately one-half as effectively as the phosphorus in dicalcium phosphate. Gillis et al. (1957) fed chicks and turkeys P 32 labeled calcium phytate and P 32 labeled monosodium ortho phosphate and then measured the amount of radioactivity retained in the tibia. They concluded that chicks utilized the phosphorus in calcium phytate only 10% as effectively as that in monosodium ortho phosphate and that the relative utilization of calcium phytate phosphorus by the turkey was less than 2%. The availability of phytate phosphorus has also been studied in phosphorus balance trials. Nikolaiczuk (1950) reported that chicks retained 14% to 18% of the phytate phosphorus in the dietary ingredients. Not all of the phytate phosphorus was recovered in the feces and the author concluded that degradation processes other than hydrolysis accounted for this unrecovered phytate. Ashton et al. (1960) fed P 32 labeled calcium phytate and observed that chicks four-weeks old retained approxi-
mately 20% of the phytate phosphorus whereas six-week old chicks retained 36% to 49% of this phosphorus. They concluded the chicks utilized one-fifth of the phytate phosphorus. Temperton and Cassidy (1964)reported chicks retained approximately 60% of the phytate phosphorus and only 50% of the non-phytate phosphorus. They indicated that the chick's total need for phosphorus could be met with plantsource phosphorus. It is apparent that wide disagreement has existed between investigators on the ability of the chick to utilize phytate phosphorus. Varied experimental methods and materials were used and may have contributed to this disagreement. These variables included the source of phytate phosphorus, criteria of response, age of the test animals, and calcium and vitamin D 3 levels in the experimental diets. Sources of Phytate Tested The sources of the phytates tested may have caused some of the discrepancies between reports on phytate phosphorus utilization by poultry. Phytate phosphorus occurs in plants as the mixed calcium-magnesium-potassium salt of phytic acid (Anderson, 1915c; Averill and King, 1926). The availability of this "natural" phytate phosphorus may differ from that in a chemically isolated fraction for at least two reasons. The first is the fact that phytic acid-protein complexes are formed in certain types of processed seed meals that reduce the solubility of these proteins (Fontaine et al., 1946). Such complexes may also cause further reduction in the availability of the phytate phosphorus by delaying the onset of enzymatic attack during the digestive process. Another reason is the source of the natural phytate phosphorus may influence its availability to the animal. Some feed ingredients contain the enzyme phytase which hydrolyzes phytate to phosphoric
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phytates as the isolated but impure chemical compound rather than relying on feed ingredients as the source. Lowe et al. (1939) reported that chicks did not efficiently utilize phytate phosphorus isolated from wheat bran. Singsen and Mitchell (1945) and Matterson et al. (1946) found calcium magnesium phytate was a poor source of phosphorus for the turkey poult. Gillis et al. (1948) showed that chicks were unable to utilize relatively pure calcium phytate. Waldroup et al. (1964a) reported the availability of the phosphorus in calcium phytate and sodium phytate was less than that of sodium phosphate. Harms et al. (1962) and Waldroup et al. (1964a) concluded that the phosphorus in phytic acid was highly available to the chick.
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dium phytate and phytic acid are more soluble and should be partially hydrolyzed to phosphoric acid which can be utilized by the chick. Accordingly, one cannot extrapolate the availability of the phosphorus in sodium phytate or phytic acid to naturally occurring phytate phosphorus. Criteria of Response Percent bone ash and weight gain have been the most common criteria used to study the utilization of phytate phosphorus. P 32 deposition from labeled phytate and phosphorus balance studies have been used to a lesser extent. The percent of bone ash is one of the most sensitive practical criteria for evaluating the availability of dietary phosphorus. It is more accurate than body weight (Nelson and Walker, 1964; Dilworth, 1966) and is little affected by other dietary variables that influence growth. Body weight gain is not an accurate measure of phosphorus utilization and its use has led to misleading conclusions. Singsen et al. (1947) and Sieburth et al. (1952) reported phytate phosphorus was more available for growth than for bone calcification. Vanderpopuliere et al. (1961) concluded plant-source phosphorus was readily available to support growth but that it would not increase the percent bone ash when the calcium:phosphorus ratio was narrowed from 4:1 to 1:1. Waldroup et al. (1964a), in an opposing view, reported calcium phytate phosphorus was more available for bone deposition than for growth. A more realistic view was expressed by Taylor (1965), commenting on the theory that the animal can partition phytate phosphorus between growth and bone calcification: "If it is agreed that the P of phytate is in all probability absorbed as phosphate ions, the concept of a greater or lesser 'availability' for a particular physiological function becomes quite unacceptable." Nelson et al. (1965) published data sup-
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acid (Anderson, 1915a, b). Wheat, rye and barley are high in phytase activity whereas oats, maize and various seed meals contain little or none of the enzyme (McCance and Widdowson, 1944; Mollgaard, 1946). Therefore, phytate phosphorus should be more available in ingredients containing this enzyme or in diets containing ingredients with a high phytase content. Chemical forms of phytate appear to offer both advantages and disadvantages for phosphorus assay purposes. These compounds are not bound as the protein complex and presumably should give a more reliable estimate of phytate phosphorus utilization per se. It would appear that compounds such as magnesium phytate are the most desirable compounds to test since they are similar in composition to natural phytate. However, neither is the same compound that existed in the plant. Calcium phytate and calcium magnesium phytate were tested in the work cited above. They were found to be a poor source of phosphorus, which suggested that natural phytate was also poorly utilized. Sodium phytate and phytic acid were other chemical phytates tested in the work cited above. Both were reported to be better sources of phosphorus than calcium phytate. However, neither was the form found in the plant. Therefore, for reasons mentioned below, they cannot be used to determine phytate phosphorus utilization. The purity and solubility of any phytate compound may influence the apparent availability of the phosphorus. Analyses in this laboratory have shown that calcium phytate, sodium phytate, and phytic acid were contaminated with ortho phosphate. This form of phosphorus would be metabolized by the animal and could lead to errors in estimating the utilization of phytate phosphorus. Calcium phytate is insoluble and is relatively inert to acid or basic hydrolysis in the pH ranges that exist in the digestive tract of poultry. Conversely, so-
UTILIZATION OF PHYTATE PHOSPHORUS
bone calcification. They explained that the exchange reaction probably was the mechanism observed, and if true, the phytate molecule removed as much phosphorus from the body as it brought in. This agreed with Common's belief that the intact phytate molecule was excreted in the feces. The exchange reaction is the simple chemical exchange of the same element between two different compounds. The exchange of P 32 from phytate with P from an inorganic source would render the P 32 available. It would appear, based on radioactivity measurements, that phytate phosphorus is utilized. However, if it is replaced with inorganic P which is rendered unavailable when incorporated into the phytate molecule, there is no net utilization of phytate phosphorus. Gillis et al. (1957) used P 32 labeled calcium phytate and P 32 labeled monosodium ortho phosphate to study phytate phosphorus utilization. Their conclusions, discussed above, were based on the amount of P 32 retained in the tibia. They also demonstrated that P 32 from NaH 2 P 32 0 4 exchanged readily with the phosphorus from calcium phytate in vitro. This agreed with the theory Singsen et al. (1950) used to explain the apparent utilization of phytate phosphorus by poults. The work of Gillis et al. (1957) emphasized the fact that the recovery of radioactivity in the body does not necessarily represent a net utilization of phytate phosphorus. It is possible for the net utilization to be zero because of the exchange reaction. The effect of age on the ability of poultry to utilize phytate phosphorus has not been clearly defined. The data available suggest that the utilization of phytate phosphorus increases with increasing age to maturity. The degree to which this is true, however, has not been established, primarily because of the types of experimental diets used. McGinnis et al. (1944) compared the
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porting this statement and explaining the differences observed between growth and bone deposition. Chicks were fed purified diets practically devoid of calcium and phosphorus. These diets were supplemented with inorganic sources of calcium and phosphorus at ratios of 4:1 and 2:1. The chicks gained weight when the calcium content of these diets was reduced to narrow the ratio. However, the source of supplemental phosphorus determined whether or not the percent bone ash increased as the calcium content of the diet was decreased. These data, obtained in the absence of phytate phosphorus, were similiar to those of Singsen et al. (1947), Sieburth et al. (1952) and Vanderpopuliere et al. (1961) who reported the possible partition of phytate phosphorus between growth and bone deposition. It is probable that the improved weight gain they observed was a response to a more favorable calcium level rather than a peculiar partition in the utilization of phytate phosphorus. If this assumption is true, then the availability of phytate phosphorus in finely ground whole wheat flour was less than indicated by Sieburth et al. (1952). Common (1939) reported the phytate was inactive in the body of the chick and the poult and passed out in the feces as the intact molecule. Singsen et al. (1950) concluded the phosphorus in the phytate molecule moved quickly and easily throughout the body of the turkey poult. Although these authors disagreed on the metabolism of the phytate molecule, they did agree on the probable availability of the phosphorus. Singsen's group fed poults P 32 labeled calcium phytate and found radioactivity in the blood, down and muscle tissue within one hour after dosing. They stated it was unlikely that the low phytase activity in the intestine would hydrolyze P 32 from the phytate molecule so rapidly. Although P32 was deposited in the bone salts, the unlabeled phytate phosphorus did not support
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Calcium phytate contains approximately
Reports have been published suggesting
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utilization of the phosphorus in a natural equal amounts of calcium and phosphorus. diet by chicks to four and eight weeks of Plant phytate is the mixed calcium magneage. The chicks had a higher percentage of sium potassium salt of phytic acid and bone ash at eight weeks. This could have therefore contains less calcium than phosbeen the result of either increased utiliza- phorus. The availability of phytate calcium tion of phytate phosphorus or a reduced has not been established and it is presumphosphorus requirement. Gillis et al. ably possible, based on the work cited (1953, 1957) observed differences in the above, that little of it is available. Furtherability of the chick and the hen to utilize more, it is also presumably possible for the phytate phosphorus. The hen diet con- phytate molecule to inactivate a portion of tained wheat bran, which probably con- the supplemental calcium in the digestive tained the enzyme phytase. Conceivably, tract. Theoretically, this could occur bepart or all of the increased ability of the cause of the low calcium-phosphorus ratio hen to utilize phytate phosphorus could of plant phytate compared to calcium phytate. have been due to wheat bran phytase. Another role of calcium on apparent Ashton et al. (1960) found differences in phytate phosphorus retention of four-week availability of phytate phosphorus concerns and six-week old chicks fed the same diets. the dietary levels fed in relation to the Temperton et al. (1965a, b, c) reported available phosphorus. This was discussed that pullets and laying hens could utilize above, but it should be reemphasized that organic sources of phosphorus. However, at it is fallacy to conclude that responses obleast three ingredients in their diets proba- tained by changing dietary calcium levels result from changes in the availability of bly contained high phytase activity. Therefore, while older poultry may utilize phytate phosphorus. phytate phosphorus more efficiently than younger birds, the use of feed ingredients Vitamin D The effect of vitamin D on phosphorus that contained phytase activity in some experiments may have overemphasized this utilization has received renewed attention in recent years. The primary function of age difference. this vitamin, demonstrated by Nicolaysen Calcium. et al. (1953) and by Keane et al. (1956) is to promote calcium absorption. This proCalcium has been shown to have an adcess is an active one which proceeds against verse effect on the availibility of phytate an electrochemical gradient (Wasserman et phosphorus. Conversely, the phytate moleal, 1961). Nicolaysen et al. (1953) concule has been observed to reduce the availcluded that the increased phosphorus ability of calcium. Phytate supplied either by dietary ingredients or in a chemical absorption they observed was secondary to form reduced calcium absorption from the the calcium absorption. Their work reintestine of humans (McCance and Wid- ceived the support of Harrison and Harridowson, 1942a, b; Krebs and Mellanby, son (1961) who concluded that phosphate 1943; Bronner et al, (1954). Hoff-Jorgen- transport was dependent of calcium. Acsen (1946) and Mellanby (1949) observed cording to Rasmussen and DeLuca (1963), a similar effect in dogs. Melanby attributed the only regulation of phosphate absorption this to the precipitation of insoluble penta- by vitamin D is indirectly through changes in calcium absorption. calcium phytate.
UTILIZATION OF PHYTATE PHOSPHORUS
ferentiate between the response to vitamin D 3 because of the imbalanced calciumavailable phosphorus ratio and in enhancing phytate phosphorus utilization. With both of these actions occurring simultaneously, the results could overemphasize the value of vitamin D 3 for improving phytate phosphorus utilization. A second theory suggested that vitamin D increased the production of phytase in the intestine or that it enhanced the activity of the phytase contained in the feed ingredients. The report by Spitzer et al. (1948) does not agree with this theory. They were unable to increase the intestinal phytase activity by adding vitamin D to tissue homogenates. Pileggi et al. (1955) published evidence to support this theory. They reported that vitamin D increased the intestinal phytase activity two to five times in the intact animal. Roberts and Yudkin (1961) also found that this vitamin increased phytase activity in rats. However, this theory has not been investigated fully to determine its merits.
At least two theories have been put forth to explain the mode of action of vitamin D 3 . Singsen et al. (1950) suggested that phytate phosphorus was labile, but in the absence of this vitamin the phytate molecule probably removed as much phosphorus from the body as it brought in. However, under the influence of vitamin D 3 another Phytase Enzyme radical replaced part of the phytate phosThe presence of the enzyme phytase in phorus which then became available to the certain feed ingredients and its possible seanimal. The improved phosphorus utiliza- cretion in the intestine were discussed eartion in the presence of vitamin D 3 repre- lier in this review. Additional information sented this released phytate phosphorus, on the action of phytase was reported by rather than the increased utilization of the Courtois (1945) and by Courtois and Masnon-phytate phosphorus. son (1950). Plant phytase was specific for The effect of vitamin D 3 in increasing phytate phosphorus and cleaved phosphate the utilization of the inorganic phosphorus from alternate rather than adjacent carbon cannot be totally discounted, however. It is atoms. Sandegren (1948) and Mattson and well documented that, at an optimum calci- Koutler-Andersson (1947) indicated that um to available phosphorus ratio, little, if this enzyme was active in a narrow pH any, response is obtained from vitamin D 3 . range. Proteins precipitated phytate on the Conversely, a response can be obtained if acid side, but it was precipitated by calcithe ratio is unbalanced. Vitamin D 3 re- um and magnesium ions in an alkaline consponses were obtained in most of the exper- dition. Plant phytase can hydrolyze phyiments cited above with diets containing tate phosphorus, and the conditions for its imbalanced levels of calcium and available action suggest that the enzyme would be phosphorus. It was impossible to dif- active in the digestive tract of animals.
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that vitamin D 3 improved the utilization of phytate phosphorus. Lowe et al. (1939), Singsen and Mitchell (194S) and Singsen et al. (1947) increased the bone ash in chicks and poults by feeding higher levels of vitamin D 3 . McGinnis et al. (1944) reported chicks responded to increased levels of vitamin D 3 in a manner suggesting better utilization of phytate phosphorus. Gillis et al. (1949) observed that high levels of vitamin D 3 improved the performance of chicks fed either calcium phytate or natural phytate phosphorus. Gillis et al. (1957) found that vitamin D 3 caused a small increase in the retention of phytate P 32 in the bones. Waldroup et al. (1964b) increased the weights of the chicks fed either calcium phytate or dicalcium phosphate by increasing the vitamin D 3 content of the diet.
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Singsen and Mitchell (1944) studied the middlings. These two ingredients supposedeffect of feeding an ingredient with an ap- ly contained phytase activity. The difparent high phytase activity. The addition ference between their results and those of sun-cured alfalfa meal, which presum- of Singsen and Mitchell (1944) and Temably contained phytase activity, to a chick perton et al. (1965a, b, c) suggests that diet promoted weight gain and bone ash as plant-source feed ingredients either vary in well as supplemental inorganic phosphate their original phytase content or that the whereas dehydrated alfalfa meal was enzyme was labile under the handling conineffective. They concluded that the sun- ditions of the feed ingredients. It appears cured sample contained phytase activity that specific feed ingredients cannot be that was apparently destroyed in the dehy- considered to be a consistent source of phydrated sample. If their conclusion was cor- tase. rect, then it appears that the enzyme also Curtois and Valentino (1947) found that hydrolyzed the phytate phosphorus con- purified phytase, extracted from wheat tained in the other feed ingredients. Tem- bran, was ineffective in the rat. The perton et al. (1965a, b, c) presented indi- difference between their results and those rect evidence that plant phytase was effec- of Warden and Schaible (1962) may have tive in feeds. Their diets contained 32 to reflected differences in phytase enzymes 36% wheat and 10% barley meal which from plant and bacterial sources. have been reported to be sources of phytase. These diets also contained three per- Plant Phosphorus cent grass meal which may have been Common (1940) reported the phytic similar to the sun-cured alfalfa meal acid phosphorus content of feedstuffs destudied by Singsen and Mitchell (1944). rived from processed oil seeds, including Warden and Schaible (1962) appear to soya bean meal, was one-half to two-thirds have established that bacterial phytase can of the total phosphorus. Phytic acid phosbe active in the digestive tract. They found phorus accounted for two-thirds to threethe addition of lysed E. coli cellular mate- fourths of the total phosphorus in cereal rial to the diet improved both growth and grains. bone development and suggested this was a Mollgaard (1946) showed slightly response to phytase or similar enzymes. higher concentrations of phytate phosphoIt appears, in view of these reports, that rus in processed oil seeds (70-80%) and some of the differences observed in the in cereal grains (65-85%). ability of the various species of poultry to The non-phytate phosphorus content of utilize phytate phosphorus can be ex- those ingredients mentioned above ranged plained by the presence or absence of phy- from 15-50%. The degree to which this is tase in the experimental diets. utilized by the animal has not been clearly Although the work cited above suggests established. It is questionable, from the phytase activity can be a determining fac- data available, whether any portion of the tor in phytate phosphorus utilization, the phytate phosphorus should be considered conditions for its activity have not been available. Rations formulated with one part clearly established. McGinnis et al. (1944) plant protein source for each two parts found chicks made inefficient use of phy- plant energy source will contain approxitate phosphorus in a diet that contained mately 30% non-phytate phosphorus. Con20% wheat bran and 10% wheat flour sidering this to be available, phosphorus
UTILIZATION OF PHYTATE PHOSPHORUS
Conclusions The preponderance of data suggests that phosphorus is absorbed as the inorganic phosphate ion. Therefore, the ability of the various species of poultry to utilize phytin phosphorus will depend, in the simplest terms, on their ability to liberate phosphate ions from the phytate molecule by hydrolysis. There is no evidence showing unquestionable proof that phytate is absorbed and utilized intact by any animal species. Present knowledge of calcium and phosphorus utilization and the role of vitamin D 3 permits tentative conclusions on the various species of poultry to utilize phytin phosphorus. 1. In order to be utilized, phytin phosphorus must be hydrolyzed to yield inorganic phosphate. 2. The chick absorbs and utilizes dietary phosphorus without regard to its organic or inorganic origin. The chick cannot partition the phosphorus derived from the phytate molecule between different metabolic functions in a manner different from that derived from inorganic sources. 3. Young birds have very limited ability to hydrolyze phytin phosphorus. This abili-
ty increases with age up to maturity; however, the magnitude of this increase has not been accurately quantified. 4. Calcium, at levels required by poultry, has an adverse effect upon the utilization of phytin phosphorus. The availability of phytate calcium has not been established. 5. Vitamin D 3 probably enhances the utilization of phytate phosphorus by animals to a limited extent. However, the magnitude of this increase is small and appears to be dependent upon several other dietary interrelationships. 6. Phytase enzyme, present in certain feed ingredients and possibly secreted by the intestine, hydrolizes phytate phosphorus to a form that can be utilized. Under certain conditions this enzyme will hydrolyze dietary phytate phosphorus making it available to the animal. This appears to be the most effective force at work in the digestive tract that results in utilizaion of phytate phosphorus. 7. The National Academy of SciencesNational Research Council's recommendation that 30% of the total plant phosphorus is available to animals can usually be applied to a mixture of ingredients but not to individual ingredients. REFERENCES Anderson, R. J., 1915a. The hydrolysis of phytin by the enzyme phytase contained in wheat bran. J. Biol. Chem. 20:475-482. Anderson, R. J., 1915b. The hydrolysis of the organic phosphorus compound of wheat bran by the enzyme phytase. J. Biol. Chem. 20: 483491. Anderson, R. J., 1915c. Concerning phytin in wheat bran. J. Biol. Chem. 20: 493-500. Ashton, W. M., C. Evans and P. C. Williams, 1960. Phosphorus compounds of oats. II. The utilisation of phytate phosphorus by growing chicks. J. Sci. Food Agric. 11: 722-727. Averill, H. P., and C. G. King, 1926. The phytin content of foodstuffs. J. Am. Chem. Soc. 48: 724-728.
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would agree with the NAS-NRC recommendation that 30% of the plant phosphorus is available to the animal. The NAS-NRC recommendation does not consider (a) variations in the phytate content of different ingredients, (b) the availability of the non-phytate phosphorus, and (c) the possible utilization of some of the phytate phosphorus. In view of the fact that animals can utilize some portion of the plant phosphorus, and based upon the discussion above, the NAS-NRC recommendation appears to be a close estimate of the available phosphorus in a mixture of plant materials but not for individual ingredients.
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T. S. NELSON acid on the absorption of calcium and phosphorus. 1. In dogs. Biochem. J. 40: 189-192. Kastelic, J., and R. M. Forbes, 1961. Animal nutrition and phosphates in feeds. The availability of phosphorus in plant materials to various species of animals. Chapt. 24, pp. 1549-1561, Phosphorus and its Compounds, Vol. II, J. R. Van Wazer, Ed. Interscience Publishers, Inc., N. Y. Keane, K. W., R. A. Collins and M. B. Gillis, 1956. Isotopic tracer studies on the effect of vitamin D on calcium metabolism in the chick. Poultry Sci. 35: 1216-1222. Krebs, H. A., and K. Mellanby, 1943. The effect of national wheatmeal on the absorption of calcium. Biochem. J. 37: 466-468. Lowe, J. T., H. Steenbock and C. H. Krieger, 1939. Cereals and rickets. IX. The availability of phytin-P to the chick. Poultry Sci. 18: 4044. Matterson, L. D., H. M. Scott and E. P. Singsen, 1946. The influence of sources of phosphorus on the relative efficiency of vitamin D 3 and cod liver oil in promoting calcification in poults. J. Nutr. 3 1 : 599-608. Mattson, S., and E. Koutler-Andersson, 1947. The acid-base condition in vegetation, litter and humus. X. Some properties and functions of phytin. Kgl. Lantbruks-Hogskol. Ann. 14: 290-300. McCance, R. A., and E. M. Widdowson, 1942a. Mineral metabolism of healthy adults on white and brown bread dietaries. J. Physiol. 101: 44-85. McCance, R. A., and E. M. Widdowson, 1942b. Mineral metabolism on dephytinized bread. J. Physiol. 101: 304-313. McCance, R. A., and E. M. Widdowson, 1944. Activity of the phytase in different cereals ana its resistance to dry heat. Nature, 153 : 650. McGinnis, J., L. C. Norris and G. F. Heuser, 1944. Poor utilization of phosphorus in cereals and legumes by chicks for bone development. Poultry Sci. 23 : 157-159. Mellanby, E., 1949. Rickets—producing and anticalcifying action of phytate. J. Physiol. 109: 488-533. Mollgaard, H., 1946. On phytic acid, its importance in metabolism and its enzymic cleavage in bread supplemented with calcium. Biochem. J. 40: 589-603. National Academy of Sciences-National Research Council, 1960. Nutrient requirements for domestic animals. 1. Nutrient requirements for poultry.
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on February 22, 2015
Bronner, F., R. S. Harris, C. J. Maletskos and C. E. Benda, 1954. Studies in calcium metabolism. Effect of food phytates on calcium45 uptake in children on low-calcium breakfasts. J. Nutr. 54: 523-542. Common, R. H., 1939. Phytic acid in mineral metabolism in poultry. Nature, 143: 379-380. Common, R. H., 1940. The phytic acid content of some poultry feeding stuffs. The Analyst, 65: 79-83. Courtois, J., 1945. Phytase. I. Comparative action of various enzyme preparations on inositol hexaphosphate and sodium glyceralphosphate. Bull. Soc. Chim. Biol. 27: 411-415. Courtois, J., and M. Masson, 1950. Phytase XVI. Compounds obtained after partial hydrolysis of phytin. Bull. Soc. Chim. Biol. 32: 326-332. Courtois, J., and A. Valentino, 1947. Phytase IV. Does the ingestion of phytase favor the absorption of inositol phosphates? Bull. Soc. Chim. Biol. 29:615-620. Dilworth, B. C , 1966. A study of certain factors affecting the utilization of calcium and phosphorus by the chick. Ph.D. Thesis. Mississippi State University, State College. Fontaine, T. D., W. A. Pons, Jr. and G. W. Irving, Jr., 1946. Protein-phytic acid relationship in peanuts and cottonseed. J. Biol. Chem. 164: 487-507. Gillis, M. B., K. W. Keane and R. A. Collins, 1957. Comparative metabolism of phytate and inorganic P32 by chicks and poults. J. Nutr. 62: 13-26. Gillis, M. B., L. C. Norris and G. F. Heuser, 1948. The utilization by the chick of phosphorus from different sources. J. Nutr. 35:195-207. Gillis, M. B., L. C. Norris and G. F. Heuser, 1949. The effect of phytin on the phosphorus requirement of the chick. Poultry Sci. 28: 283-288. Gillis, M. B., L. C. Norris and G. F. Heuser, 1953. Phosphorus metabolism and requirements of hens. Poultry Sci. 32 : 977-984. Harms, R. H., P. W. Waldroup, R. L. Shirley and C. B. Ammerman, 1962. Availability of phytic acid phosphorus for chicks. Poultry Sci. 4 1 : 1189-1191. Harrison, H. E., and H. C. Harrison, 1961. Intestinal transport of phosphate: action of vitamin D, calcium and potassium. Am. J. Physiol. 201: 1007-1012. Heuser, G. F., L. C. Norris, J. McGinms and M. L. Scott, 1943. Further evidence of the need for supplementing soybean meal chick rations with phosphorus. Poultry Sci. 22: 269-270. Hoff-Jorgensen, E., 1946. The influence of phytic
UTILIZATION OF PHYTATE PHOSPHORUS
185-193. Sunde, M. L., and H. R. Bird, 1956. A critical need of phosphorus for the young pheasant. Poultry Sci. 35: 424-430. Taylor, T. G., 1965. The availability of the calcium and phosphorus of plant materials for animals. Proc. Nutr. Soc. 24: 105-112. Temperton, H., and J. Cassidy, 1964. Phosphorus requirements of poultry. I. The utilization of phytin phosphorus by the chick as indicated by balance experiments. Br. Poultry Sci. S: 7580. Temperton, H., F. J. Dudley and G. J. Pickering, 1965a. Phosphorus requirements of poultry. IV. The effects on growing pullets of feeding diets containing no animal protein or supplementary phosphorus. Br. Poultry Sci. 6: 125133. Temperton, H., F. J. Dudley and G. J. Pickering, 1965b. Phosphorus requirements of poultry. V. The effects during the subsequent laying year of feeding growing diets containing no animal protein or supplementary phosphorus. Br. Poultry Sci. 6: 135-141. Temperton, H., F. J. Dudley and G. J. Pickering, 1965c. Phosphorus requirements of poultry. VI. The phosphorus requirements of growing pullets between 8 and 18 weeks of age. Br. Poultry Sci. 6:143-151. Vanderpopuliere, J. M., C. B. Ammerman and R. H. Harms, 1961. The relationship of calciumphosphorus ratios to the utilization of plant and inorganic phosphorus by the chick. Poultry Sci. 40: 951-957. Waldroup, P. W., C. B. Ammerman and R. H. Harms, 1964a. The availability of phytic acid phosphorus for chicks. 2. Comparison of phytin phosphorus sources. Poultry Sci. 4 3 : 426432. Waldroup, P. W., C. B. Ammerman and R. H. Harms, 1964b. The availability of phytic acid phosphorus for chicks. 3. Effect of calcium and vitamin D 3 levels on the utilization of calcium phytate. Poultry Sci. 43: 926-931. Warden, W. K., and P. J. Schaible, 1962. Action of antibiotics in stimulating growth of poultry. 1. Effect of E. coli and fecal preparations. Poultry Sci. 4 1 : 725-732. Wasserman, R. H., F. A. Kallfelz and C. L. Comar, 1961. Active transport of calcium by rat duodenum in vivo. Science, 133 : 883-884.
AUGUST 21-25, FIFTY-FIFTH ANNUAL MEETING OF THE POULTRY SCIENCE ASSOCIATION, UNIVERSITY OF NEW HAMPSHIRE, DURHAM, N.H.
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Nelson, T. S., W. A. Hargus, N. Storer and A. C. Walker, 1965. The influence of calcium on phosphorus utilization by chicks. Poultry Sci. 44: 1508-1513. Nelson, T. S., and A. C. Walker, 1964. The biological evaluation of phosphorus compounds. A summary. Poultry Sci. 43 : 94-98. Nicolaysen, R., N. Eeg-Larsen and O. J. Malm, 1953. Physiology of calcium metabolism. Physiol. Revs. 33:424-444. Nikolaiczuk, N., 1950. The availability and retention of phosphorus from organic and inorganic sources by the chick. Abs. of Doctoral Diss., Ohio St. U. Press. Pileggi, V. J., H. F. DeLuca and H. Steenbock, 1955. The role of vitamin D and intestinal phytase in the prevention of rickets in rats on cereal diets. Arch. Biochem. Biophys. 58: 194204. Rasmussen, H., and H. F. DeLuca, 1963. Calcium homeostasis. Ergebn. Physiol. 53: 108-173. Roberts, A. H., and J. Yudkin, 1961. Effect of phytate and other dietary factors on intestinal phytase and bone calcification in the rat. Brit. J. Nutr. 15:457-471. Sandegren, E., 1948. Barley phytin in malting and brewing. J. Inst. Brewing, 54: 200-207. Sieburth, J. F., J. McGinnis, T. Wahl and B. A. McLaren, 1952. The availability of the phosphorus in unifine flour for the chick. Poultry Sci. 3 1 : 813-818. Singsen, E. P., L. D. Matterson and A. Kozeff, 1950. Phosphorus in poultry nutrition. IV. Radioactive phosphorus as a tracer in studying the metabolism of phytin by the turkey poult. Poultry Sci. 29: 635-639. Singsen, E. P., L. D. Matterson and H. M. Scott, 1947. Phosphorus in poultry nutrition. III. The relationship betw:en the source of vitamin D and the utilization of cereal phosphorus by the poult. J. Nutr. 33 : 13-26. Singsen, E. P., and H. H. Mitchell, 1944. Soybean meal chick rations need no inorganic phosphorus supplements. Poultry Sci. 23 : 152-153. Singsen, E. P., and H. H. Mitchell, 1945. Phosphorus in poultry nutrition. I. The relation between phytin and different sources of vitamin D. Poultry Sci. 24: 479-480. Spitzer, R. R., G. Maruyama, L. Michaud and P. H. Phillips, 1948. The role of vitamin D in the utilization of phytin phosphorus. J. Nutr. 35:
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