Relationships Between Dietary and Plasma Concentrations of Calcium and Phosphorus in Intact and Ultimobranchialectomized Chickens I2 ' 3 J . D . GARLICH AND D . M . BRYANT
Department of Poultry Science, School of Agriculture and Life Sciences, North Carolina State University, Raleigh, North Carolina 27607 (Received for publication June 10, 1974)
POULTRY SCIENCE 54: 388-395, 1975
r
INTRODUCTION
HE role of calcitonin in the chicken is not as well defined as in mammals such as the rat. Whereas calcitonin from various species will produce hypocalcemia in rats (Hirsch, 1971), neither porcine calcitonin nor chicken ultimobranchial (UB) gland extracts have been found to produce hypocalcemia in chickens (Gonnerman et al., 1972; Urist, 1967) unless the chickens were first partially
1. Paper Number 4142 of the Journal Series of the North Carolina State University Agricultural Experiment Station, Raleigh, North Carolina. 2. The use of trade names does not imply endorsement by the North Carolina Agricultural Experiment Station nor criticism of similar products not mentioned. 3. A preliminary report of this work was presented at the 62nd Annual Meeting of the Poultry Science Association, Brookings, South Dakota, August, 1973. A portion of this work was submitted in a thesis by the junior author in partial fulfilment of the requirements for the M.S. degree, North Carolina State University, Raleigh, North Carolina, May, 1973.
parathyroidectomized (Kraintz and Intscher, 1969), and this latter observation has not been confirmed (Gonnerman et al., 1972). However, injection of porcine calcitonin into chickens has been reported to reduce serum magnesium (Lloyd and Collins, 1970). Gray and Munson (1969) demonstrated that thyrocalcitonin is necessary for the prevention of actue hypercalcemia in rats which consume a meal containing calcium. However, Gonnerman et al. (1972) concluded that in the chicken the control of acute hypercalcemia was not a role of ultimobranchial calcitonin. In mammals, e.g., the pig, calcitonin secretion is stimulated by a rise in serum calcium (Cooper et al, 1971). In chicks the UB glands hypertrophy when they consume a high calcium diet (Chan et al., 1969; Mueller et al, 1970). Prolonged consumption (from 8 to 22 weeks of age) of a diet containing 2.4% calcium by chickens with their UB glands intact resulted in hypercalcemia, hypophosphatemia, and nephrosis when the diet con388
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ABSTRACT Two experiments were conducted with cockerels to determine whether the presence or absence of the ultimobranchial glands would influence the relationship between dietary and plasma calcium and phosphorus. Broiler type cockerels, 16 weeks of age which had been sham operated (SHAM) or ultimobranchialectomized (UBX) 1 to 3 weeks earlier, were fed diets containing 0.8 or 2.4% calcium and 0.13 to 0.33% phosphorus. The SHAM cockerels fed diets containing 0.8% Ca and 0.13% P did not develop hypercalcemia whereas the UBX cockerels fed this diet developed slight significant hypercalcemia after 17 to 21 days. In Experiment I, SHAM cockerels fed the diet containing 2.4% Ca and 0.13% P developed mild, chronic hypercalcemia (12.7 mg./lOO ml.) with a plasma phosphorus of 3.03 mg. P/100 ml., whereas the UBX cockerels fed the same diet developed severe hypercalcemia (16.0 mg./100 ml.) and hypophosphatemia, 1.68 mg. P/100 ml. In Experiment 2 the following plasma values were observed after 17 days of consuming the experimental diets: SHAM fed 2.4% Ca and 0.13% P had 10.6 mg. Ca/100 ml. and 3.59 mg. P/100 ml., whereas UBX fed the same diet had 12.8 mg. Ca/100 ml. and 2.24 mg. P/100 ml. The UBX fed 2.4% Ca and 0.33% P for 17 days had plasma values of 10.8 mg. Ca/100 ml. and 4.48 mg. P/100 ml. It is concluded that the presence of the ultimobrancial glands are essential to the regulation of plasma calcium and phosphorus in chickens which consume high calcium-low phosphorus diets.
ULTIMOBRANCHIALECTOMIZED CHICKENS
tained 0.4% available phosphorus but not when the diet contained 0.6% available phosphorus (Shane and Young, 1969, Shane et al., 1969). For chickens 8 to 22 weeks of age the dietary requirement is approximately 0.8% calcium and 0.4% available phosphorus (N.R.C., 1971). Brown et al. (1970) reported that UBX growing chicks fed a diet containing 1.03% calcium and 0.74 phosphorus had lower serum phosphorus values than did sham operated controls.
MATERIALS AND METHODS Animals. Pilch-Dekalb cockerels, 16 to 22 weeks of age, were maintained in individual cages in a ventilated windowless room, with 16 hours of artificial light each day. Room temperature was 21° C. Feed and water were available ad libitum. Diets. The basal diet (Table 1) contained soybean meal and yellow corn supplemented with sufficient vitamins and minerals (except for calcium and phosphorus) to meet or exceed the 1971 National Research Council (N.R.C.) recommended nutrient requirements. The diet contained 2 times the N.R.C. requirement for vitamin D 3 . The corn and soybean meal were obtained from large stocks each of which had been blended in order to insure that all samples taken for diet formulation during the course of these experiments would have the same chemical composition. The contributions of dietary calcium and phosphorus from the corn and soybean meal were estimated from standard tabular values for these feedstuffs (Scott et al., 1969). The combination of corn plus soybean meal in the basal diet contributed 0.09% calcium, 0.3% total phosphorus, and 0.13% available phosphorus. Available phos-
TABLE 1.—Composition of the basal diet Percent Ingredients of diet Soybean meal (48.5% protein) 30IKJ Yellow corn 61.40 Vitamin premix' 1.00 Choline CI 0.20 D,L-Methionine 0.30 Cottonseed oil 2.00 Ethoxyquin2 + Mineral Mix3 1.61 CaC0 3 2.00 KH 2 P0 4 0.88 Glucose monohydrate 0.61 'Vitamin premix provides in mg./kg. of diet: D-Ca pantothenate 30, niacin 60, thiamine HC1 15, riboflavin 15, pyridoxine HC1 8, folic acid 6, menadione NaHS0 3 3, D-biotin 0.6, vitamin E (276 I.U./g.) 360, vitamin A (325 I.U./mg.) 15.4, vitamin D 3 (200 I.U./mg.) 5.0, vitamin B12 (132 mg./kg.) 272, glucose H 2 0 9,210. 2 Ethoxyquin is 6-ethoxy-l, 2-dihydro-2, 2, 4,trimethyl quinoline, an antioxidant manufactured by Monsanto Chemical Co., St. Louis, Mo., added at 125 mg./kg. of diet. 3 Mineral mix provides in g./kg. diet: NaHC0 3 6.5, NaCl 5.0, MgC03 3.0, FeSO • 7 H 2 0 0.71, MnS0 4 H 2 0 0.33, ZnS0 4 • 7 H 2 0 0.46, CuS0 4 • 5 H 2 0 0.07, Ca(I0 3 ) 2 • 6 H 2 0 0.01. phorus is organic plus inorganic phosphorus from all dietary ingredients but excluding the plant seed phytic acid phosphorus which is indigestible by the chickens (Scott et al., 1969). The K H 2 P 0 4 i n the basal diet provided 0.2% inorganic phosphate. The basal diet thus contained 0.33% available phosphorus. Decreases in dietary phosphorus content were made by substituting glucose for K H 2 P 0 4 . The basal diet supplied 0.8% calcium from C a C 0 3 . The calcium content of the diet was increased by adding 4 g. of CaCO 3 /100 g. of diet. This produced a diet containing 2.4% calcium. In order that the ratio of energy to other nutrients not be disturbed, the additional C a C 0 3 was added to the entire diet rather than substituted for glucose. Surgical Procedure. The endogenous source of calcitonin in the chicken is in the ultimo-
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The purpose of our studies was to determine whether or not the ultimobranchial gland plays a role in the regulation of plasma calcium and phosphorus in cockerels consuming high calcium-low phosphorus diets.
389
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J. D . GARLICH AND D . M .
Blood Collection and Analysis. Heparinized blood samples were obtained from the wing 4. Hyfrecator: manufactured by the Birtcher Corp. Medical Div. 4371 Valley Road, Los Angeles, Calif. 90032.
vein and the plasma was separated by centrifugation. Plasma phosphate was determined by the procedure of Goldenberg and Fernandez (1966). Plasma calcium was determined by the following modification of the fluoremetric method of Kepner and Hercules (1963). Ten to twenty |xl. of plasma were added directly to 5 ml. of a solution containing 7 mg. calcein/liter of 0.8N KOH in clear polystyrene culture tubes. Fluorescence was then determined. Statistical Analysis. Data were analyzed for differences between control and treated groups using a 2-tailed t-test. Values in the tables indicate the mean ± standard error (SE). Experiment 1. Establishment of a Dietary Phosphorus Level which Results in Hypercalcemia in 16 to 23 Week Old Cockerels Fed High Calcium Diets. The cockerels were 16 weeks of age at the beginning of the experiment. There were 10 cockerels in each of 4 groups: sham operated (SHAM) and ultimobranchialectomized (UBX) groups were fed diets containing either 0.8% or 2.4% calcium. The four groups were designated 0.8-S, 0.8-UBX, 2.4-S, and 2.4-UBX. The experiment was conducted over 43 days during which the dietary phosphorus content was altered several times as indicated in Tables 2 and 3. Experiment 2. Time Course of Development of Hypercalcemia and Hypophosphatemia in Cockerels Fed High Calcium-Low Phosphorus Diets. Fifty cockerels 16 weeks of age which had been either UBX or sham operated were divided into five groups of 10 each. During the pre-experimental period of seven days all five groups were fed the basal diet which contained 0.8% calcium and 0.33% available phosphorus. On the subsequent experimental period of 17 days the groups were fed the following diets and given
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branchial (UB) glands not the thyroid glands (Copp et al., 1967; Tauber, 1967; Hoyt et al., 1972). The technique for surgical removal of each pair of UB glands was conducted under pentobarbital anesthesia according to the following modification of the method of Garlich (1971). The Hyfrecator 4 was used to cut much of the fascia which held the UB gland. The gland could then be grasped with a forceps, and gently manipulated such that a curved mosquito forceps could be used to clamp the tissue which lay between the UB gland and the jugular vein. A micro-dissecting scissor with pencil grip handle was used to excise the gland. The remaining severed tissue was cauterized with the Hyfrecator to destroy any remaining UB tissue and seal blood vessels prior to releasing the forceps. Sham operations were conducted by the same procedure except that the UB glands were exposed and gently manipulated but otherwise left intact. The cockerels were 12 to 15 weeks of age when operated upon. The birds were allowed to recover for at least one week before beginning the experiments. During this time they were fed a commercial poultry growing feed containing 1% calcium and 0.6% available phosphorus. Upon termination of the experiment the cockerels were necropsied with the aid of a dissecting scope for any visible sign of unremoved UB tissue. The area surrounding the UB and parathyroid glands was free of adipose tissue in this variety of chicken. The parathyroids and the presence or absence of UB tissue could be readily ascertained. The results from 2 out of a total of 50 cockerels were not included because UB tissue was identified or suspected upon necropsy.
BRYANT
11.28** ±0.18
5.94 ±0.32
11.21 ±0.17
11 04*** ±0.19
0.8-UBX
4.08 ±0.35
10.55 ±0.07
10.3 ±0.0
10.4 ±0.2
16.0 ±0.8
12.7 ±0.3
C
33
1 The numbers indicate the day of the experimental period on which plasma Ca or P was determine mark the duration of feeding a given % of dietary P. 2 Each group consisted of 8 to 10 cockerels except after day 38 Group 0.8-S had 6 and 0.8-UBX had 7. 3 Mean ± SE. For a given day, means followed by notation are significantly different from their *** = P < 0.05, 0.01, 0.001, respectively).
3.34 ±0.27
10.59 ±0.14
0.13% P 10.43 ±0.17
5.88 ±0.31
11.14 ±0.17
9.77 ±0.11
0.8-SHAM
1.68*** ±0.20
12.74 ±0.41
P
29
12.81 ±0.77
Ca
27 0.13% P
3.74* ±0.31
11.23 ±0.19
11.33*** ±0.19
2.4-UBX
Ca
22
Days 1
3.03 ±0.26
0.20% P
16
11.73 ±0.51
12
11.11 ±0.38
P
12
4.93 ±0.40
Ca
11.48 ±0.17
Ca
10.313 ±0.13
Group 2
8 0.33% P '
2.4-SHAM
0
TABLE 2.—Experiment 1. Plasma calcium and phosphorus concentrations (mg./lOO ml.) in UBX an phosphorus content at two dietary calcium levels (0.8 and 2.4%
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J. D. GARLICH AND D. M. BRYANT
TABLE 3.—Experiment 2. Plasma calcium and phosphorus concentrations in UBX or SHAM operated cockerels fed diets of different calcium/phosphorus ratios Pre-exp., 1 days -7 Group 2
Experimental period, days 4
0
Ca, mg ./100 ml.
8
12
17
Ca, mg./lOOml.
Diet C a / P
9.78 3 ±0.10
10.66 ±0.19
2.4/0.13
10.41 ±0.33
11.04 ±0.24
11.09 ±0.16
10.55 ±0.21
2.4-UBX
10.23* ±0.18
11.49** ±0.18
2.4/0.13
11.48 ±0.42
11.75 ±0.50
12.69** ±0.47
12.81*** ±0.35
2.4-UBX, 0.33P
10.14* ±0.13
11.54** ±0.20
2.4/0.33
10.71 ±0.20
10.94 ±0.25
10.44** ±0.23
10.82*** ±0.14
0.8-SHAM
10.00 ±0.19
10.36 ±0.24
0.8/0.13
10.72 ±0.26
10.31 ±0.19
10.13 ±0.13
10.07 ±0.20
0.8-UBX
10.49* ±0.09
11.45** ±0.21
0.8/0.13
11.04 ±0.17
10.70 ±0.18
10.65 ±0.23
11.24*** ±0.21
2.4-SHAM
5.363 ±0.31
5.51 ±0.21
2.4/0.13
5.15 ±0.13
3.84 ±0.24
3.44 ±0.22
3.59 ±0.21
2.4-UBX
6.07 ±0.23
5.51 ±0.21
2.4/0.13
4.76 ±0.29
2.89* ±0.27
2.40** ±0.21
2.24*** ±0.21
2.4-UBX, 0.33P
5.52 ±0.18
5.29 ±0.15
2.4/0.33
5.26 ±0.14
4.81** ±0.15
4.43** ±0.22
4.48** ±0.17
0.8-SHAM
5.96 ±0.15
5.31 ±0.27
0.8/0.13
4.88 ±0.23
4.13 ±0.33
4.29 ±0.31
4.22 ±0.36
0.8-UBX
5.35* ±0.18
5.11 ±0.17
0.8/0.13
4.78 ±0.26
4.13 ±0.36
4.09 ±0.37
3.69 ±0.29
P, mg. /100 ml.
P, mg./lOOml.
'All cockerels were fed a diet containing 0.8% Ca/0.3% P during pre-exp. period and then fed diets with the Ca/P ratios indicated on days 1 to 17. 2 Each group consisted of 8 to 10 cockerels except Group 2.4-UBX-0.33 on days 8 to 12 had 7, and3 on day 17 had 5. Means ± SE. For a given day, means followed by notation are significantly different (*, **,*** = P < 0.05, 0.01, 0.001, respectively) from their respective control. The 2.4 UBX-0.33 was compared to 2.4-UBX.
the respective designations: sham operated fed 0.8% Ca, 0.13% P (0.8-S), UBX fed 0.8% Ca, 0.13% P (0.8-UBX), sham operated fed 2.4% Ca, 0.13% P (2.4-S) UBX fed 2.4% Ca, 0.13% P (2.4-UBX) and UBX fed 2.4% Ca and 0.33% P (2.4-UBX-0.33). Plasma calcium and phosphorus were determined during the pre-experimental period on days designated - 7 and 0, and on days 4, 8, 12, and 17 of the experimental period. At the beginning of the experiments each treatment group contained 10 cockerels. During the course of the experiments a few cockerels were diagnosed as having Marek's disease and were removed. The actual
number of cockerels studied are indicated in footnotes to the tables. RESULTS Table 2 shows the plasma calcium and phosphorus concentrations of cockerels in experiment 1. Initially the UBX cockerels had significantly higher plasma calcium concentrations relative to the sham operated controls. All cockerels had been consuming a commercial broiler grower diet containing 1.0% calcium and 0.6% available phosphorus. Eight days after changing to the experimental diets plasma calcium concentrations were the same for all 4 groups of cockerels. On day
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2.4-SHAM
ULTIMOBRANCHIALECTOMIZED CHICKENS
mental period when the diet contained 0.33% P, and again 17 days after beginning to consume the diet containing 0.13% phosphorus. Throughout the experiment the plasma calcium concentrations were consistently higher in the 2.4-UBX and 0.8-UBX relative to their sham operated controls although the differences were not always statistically significant. The plasma phosphorus concentration (Table 3) of the 2.4-UBX was significantly lower (P < 0.05) than that of 2.4-S 8 days after beginning consumption of the 0.13% P diet, and remained significantly lower (P < 0.01) throughout the remainder of the experiment. The plasma phosphorus concentrations of the 0.8-UBX, 0.8-S, and 2.4-S decreased from pre-experiment concentrations but did not differ significantly from each other at the same points in time. The plasma phosphorus concentrations of 2.4-UBX-0.33 P fed 0.33% dietary phosphorus throughout remained high and was significantly greater (P < 0.01) than the 2.4-UBX fed 0.13% dietary phosphorus on days 8, 12, and 17. Individual body weight gain was determined during the course of the experiments. There were no significant differences in average body weight gain among any of the treatment groups in either experiment. DISCUSSION The results of these experiments indicated that severe chronic hypercalcemia and concomitant hypophosphatemia developed in UBX but not sham-operated chickens fed high calcium-low phosphorus diets. Our experimental approach differed in at least two aspects from that of most other investigations of chickens. One, we modified the dietary proportions of calcium and phosphorus, and two, we conducted a longitudinal study which monitored the changes in plasma calcium and phosphorus over a period of several weeks. Most other investigations have been concerned with the short term, acute effects of
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12 the dietary phosphorus content was reduced to 0.20% and then on day 22 dietary P was reduced to 0.13%. By day 33 the 2.4-UBX had significantly higher plasma calcium concentrations than the 2.4-S (16.02 vs. 12.71 mg./lOO ml.). The 2.4-S showed increasing plasma calcium concentrations as dietary phosphorus was decreased. On day 35 the dietary P of 2.4-UBX and 2.4-S was increased to 0.33%. By day 43 plasma calcium of both groups had declined. The 2.4-S had a normal plasma calcium concentration (10.27 mg./lOO ml.) but the 2.4-UBX were still significantly hypercalcemic, 13.44 mg./lOO ml. (P < 0.001). Relative to the 0.8-S controls, the 0.8-UBX had significantly higher plasma calcium on days 0, 16, and 43. When the diet contained 0.13% phorphorus the 0.8-UBX appeared to develop an increasing plasma calcium concentration which was significantly different from the 0.8-S by day 43. The plasma P (Table 2) of 2.4-UBX was significantly lower than 2.4-S at all dietary phosphorus levels. The 2.4-UBX developed severe hypophosphatemia by day 29. After increasing dietary phosphorus to 0.33% on day 35, plasma P of both groups increased but a significant difference was still evident on day 41. The 0.8-S and 0.8-UBX continued to receive the 0.13% P diet. The 0.8-UBX did not show a significantly lower plasma P relative to 0.8-S on any given day of the experiment. In experiment 2, the plasma calcium concentrations (Table 3) of 2.4-UBX was significantly greater than 2.4-S 12 days after the dietary phosphorus was reduced from 0.33 to 0.13%. The plasma calcium concentration of the 2.4-UBX-0.33 P which consumed a diet containing 0.33% phosphorus throughout the experiment did not become elevated and on days 12 and 17 was significantly lower than 2.4-UBX. The plasma calcium concentrations of 0.8-UBX relative to 0.8 S were significantly elevated during the pre-experi-
393
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J. D. GARLICH AND D. M. BRYANT
A possible explanation of our results is that the absence of the UB glands and consequently endogenous calcitonin in the UBX group fed the high calcium-low phosphorus diet resulted in failure to maintain a sufficiently elevated plasma and kidney phosphorus concentration. The suppression of
hydroxylation of 25 HCC was reduced and the resulting increase in 1-25 DHCC increased intestinal calcium absorption and plasma calcium concentration. The maintenance of high plasma phosphorus in our 2.4-UBX-0.33 P group in Experiment 2 resulted in normal plasma calcium concentration. This observation is also in accordance with the work of Tanaka and associates (Tanaka and DeLuca, 1973; Tanaka et al., 1973). ACKNOWLEDGEMENTS The authors are grateful for the advice of Dr. C. H. Hill, Dr. P. B. Hamilton and for the technical assistance of Mrs. Carole Morris. REFERENCES Brown, D. M., D. Y. E. Perey and J. Jowsey, 1970. Effects of ultimobranchialectomy on bone composition and mineral metabolism in chickens. Endocrinology, 87: 1282-1891. Chan, A. S. J. D. Cipera and L. F. Belanger, 1969. The ultimobranchial gland of the chick and its response to a high calcium diet. Rev. Can. Biol. 28: 19-31. Cooper, C. W., L. J. Deftos and J. T. Potts, Jr., 1971. Direct measure of in vivo secretion of pig thyrocalcitonin by radioimmunoassay. Endocrinology, 88: 747-754. Copp, D. H., D. W. Cockcroft and Y. Kueh, 1967. Ultimobranchial origin of calcitonin. Hypocalcemic effect of extracts from chicken glands. Canad. J. Physiol. 45: 1095-1099. DeLuca, H. F., 1972. The functional metabolism of vitamin D 3 . In: Calcium Parathyroid Hormone, and the Calcitonins, Ed. R. V. Talmage and P. L. Munson. Excerpta Medica, Amsterdam, p. 221-235. Garlich, J. D., 1971. A technique for the surgical removal of the ultimobranchial glands from the domestic fowl. Poultry Sci. 50: 700-702. Goldenberg, H., and A. Fernandez, 1966. Simplified method for the estimation of inorganic phosphorus in body fluids. Clinical Chem. 12: 871-876. Gonnerman, W. A., R. P. Breitenbach, W. F. Erfling and C. S. Anast, 1972. An analysis of ultimobranchial gland function in the chicken. Endocrinology, 91: 1423-1429. Gray, T. K., and P. L. Munson, 1969. Thyrocalcitonin: evidence for physiological function. Science, 166: 512-513.
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calcitonin or with one exception (Brown et al., 1970) have not included dietary calcium and phosphorus as experimental variables. Our results indicate that the ultimobranchial glands are involved in the regulation of both plasma calcium and phosphorus concentrations in the chicken. The administration of exogenous calcitonin will be required to establish whether or not ultimobranchial calcitonin is indeed responsible for the differences observed under our experimental conditions. Whether the primary effect of the absence of the UB glands in our experiments was on calcium or phosphorus is unknown. Talmage et al. (1973) have clearly shown that in the thyroidectomized rat calcitonin modulates plasma phosphate concentration. Tanaka and Deluca (1973) and Tanaka et al. (1973) reported that the phosphate concentration of the kidney tuble of the rat correlates well with the 1-a hydroxylation of 25 hydroxycholecalciferol (25 HCC) to la-25dihydroxycholecalciferol (1-25 DHCC), the compound which is considered to be the metabolite most responsible for both intestinal calcium absorption and bone mineral resorption (DeLuca, 1972). Low plasma and kidney phosphate concentrations coincided with increased synthesis of 1-25 DHCC whereas high plasma phosphate concentrations were correlated with decreased synthesis. It was also shown that kidney phosphorus concentration was influenced by dietary phosphorus. They hypothesized that calcitonin may increase kidney phosphorus content and thereby suppress synthesis of 1-25 DHCC. Previously, Olson et al. (1972) had shown that calcitonin inhibits vitamin D-induced intestinal calcium absorption.
ULTIMOBRANCHIALECTOMIZED CHICKENS
Nutrition of the Chicken, M. L. Scott and Assoc. Publishers, Ithaca, N.Y. Shane, S. M., and R. J. Young, 1969. Renal and parathyroid changes produced by high calcium intake in growing pullets. Avian Dis. 13: 558-567. Shane, S. M., R. J. Young and L. Krook, 1969. Metabolic disturbances in replacement pullets produced by high calcium diets. Proceedings of the 1968 Cornell Nutrition Conference for Feed Manufacturers. Department of Poultry Science, Cornell University, Ithaca, N.Y. p. 126-131. Talmage, R. V., L. A. Whitehurst, and J. J. B. Anderson, 1973. Effect of calcitonin and calcium infusion on plasma phosphate. Endocrinology 92: 792-798. Tanaka, Y., and H. F. DeLuca, 1973. The control of 25-hydroxyvitamin D metabolism by inorganic phosphorus. Arch. Biochem. Biophys. 154: 566-574. Tanaka, Y., H. Frank and H. F. DeLuca, 1973. Intestinal calcium transport: stimulation by low phosphorus diet. Science 181: 564-566. Tauber, S. D., 1967. The ultimobranchial origin of calcitonin. Proc. Nat. Acad. Sci. U.S.A. 58: 16841687. Urist, M. R., 1967. Avian parathyroid physiology: Including a special comment on calcitonin. Amer. Zool. 7: 883-895.
NEWS AND NOTES (Continued from page 349) Chang, T. S., M. S. Rheins and A. R. Winter, 1959. The significance of the bursa of Fabricius in antibody production. 3. Resistance to Salmonella typhimurium infection. Poultry Sci. 38: 174-176. EUROPEAN SYMPOSIUM ON POULTRY MEAT The second European Symposium on Poultry Meat will be held May 12-16, 1975, at the Bilderberg Conference Hotel, Oosterbeek, The Netherlands. It is being organized by Sub-Committee 4B (Poultry Meat Quality) of the European Federation of Branches of the World's Poultry Science Association. Official language of the Symposium will be English. Attendance is open to all interested in quality of poultry meat. The theme of the program is: Influences on quality of poultry meat. The program will have plenary, contributed papers and focal topic sessions.
The three plenary sessions are: Quality (definition, methods of measurement, interpretation of data); Influence of production factors on quality; and Influence of processing factors on quality. The focal topic and sessions will be on: Turkey meat, Sensory testing, Mechanically deboned meat, Scalding, Pesticides and other chemicals in poultry meat, Veterinarian inspection, and Microbiological aspects of quality. Further information may be obtained from the Symposium Secretariat: Dr. B. Erdtsieck, Ruitersmolenweg 21, Beekbergen, The Netherlands. CONGRESS OF PACIFIC SCIENCE ASSOCIATION The Thirteenth Congress of the Pacific Science Association will be held in Vancouver, British Columbia, Canada, on the campus of the University of British
(Continued on page 404)
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Hirsch, P. F., 1971. Thyrocalcitonin and its role in calcium regulation in mammals. J. Exp. Zool. 178: 139-149. Hoyt, R. F., A. H. Tashjian, Jr. and D. W. Hamilton, 1972. Distribution of thyroid, parathyroid and ultimobranchial hypocalcemic factors in birds. 1. Thyroid and ultimobranchial calcitonins in pigeons and pullets. Endocrinology, 91: 770-783. Kepner, B. L.,and D. M. Hercules, 1963. Fluoremetric determination of calcium in blood serum. Anal. Chem. 35: 1238-1240. Kraintz, L., and K. Intscher, 1969. Effects of calcitonin on the domestic fowl. Can. J. Physiol. Pharm. 47: 313-315. Mueller, G. L., C. S. Anast and R. P. Breitenbach, 1970. Dietary calcium and ultimobranchial body and parathyroid gland in the chicken. Am. J. Physiol. 218-1722. National Research Council, 1971. Nutrient requirements for domestic animals. 1. Nutrient requirements for poultry. 6th ed., National Academy of Sciences, Washington, D.C. Olson, E. B., Jr., H. F. DeLuca and P. T. Potts, Jr., 1972. Calcitonin inhibition of vitamin D-induced intestinal calcium absorption. Endocrinology, 90: 151-157. Scott, M. L., M. C. Nesheim and R. J. Young, 1969.
395
Department of Poultry Science, School of Agriculture and Life Sciences, North Carolina State University, Raleigh, North Carolina 27607 (Received for publication June 10, 1974)
POULTRY SCIENCE 54: 388-395, 1975
r
INTRODUCTION
HE role of calcitonin in the chicken is not as well defined as in mammals such as the rat. Whereas calcitonin from various species will produce hypocalcemia in rats (Hirsch, 1971), neither porcine calcitonin nor chicken ultimobranchial (UB) gland extracts have been found to produce hypocalcemia in chickens (Gonnerman et al., 1972; Urist, 1967) unless the chickens were first partially
1. Paper Number 4142 of the Journal Series of the North Carolina State University Agricultural Experiment Station, Raleigh, North Carolina. 2. The use of trade names does not imply endorsement by the North Carolina Agricultural Experiment Station nor criticism of similar products not mentioned. 3. A preliminary report of this work was presented at the 62nd Annual Meeting of the Poultry Science Association, Brookings, South Dakota, August, 1973. A portion of this work was submitted in a thesis by the junior author in partial fulfilment of the requirements for the M.S. degree, North Carolina State University, Raleigh, North Carolina, May, 1973.
parathyroidectomized (Kraintz and Intscher, 1969), and this latter observation has not been confirmed (Gonnerman et al., 1972). However, injection of porcine calcitonin into chickens has been reported to reduce serum magnesium (Lloyd and Collins, 1970). Gray and Munson (1969) demonstrated that thyrocalcitonin is necessary for the prevention of actue hypercalcemia in rats which consume a meal containing calcium. However, Gonnerman et al. (1972) concluded that in the chicken the control of acute hypercalcemia was not a role of ultimobranchial calcitonin. In mammals, e.g., the pig, calcitonin secretion is stimulated by a rise in serum calcium (Cooper et al, 1971). In chicks the UB glands hypertrophy when they consume a high calcium diet (Chan et al., 1969; Mueller et al, 1970). Prolonged consumption (from 8 to 22 weeks of age) of a diet containing 2.4% calcium by chickens with their UB glands intact resulted in hypercalcemia, hypophosphatemia, and nephrosis when the diet con388
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ABSTRACT Two experiments were conducted with cockerels to determine whether the presence or absence of the ultimobranchial glands would influence the relationship between dietary and plasma calcium and phosphorus. Broiler type cockerels, 16 weeks of age which had been sham operated (SHAM) or ultimobranchialectomized (UBX) 1 to 3 weeks earlier, were fed diets containing 0.8 or 2.4% calcium and 0.13 to 0.33% phosphorus. The SHAM cockerels fed diets containing 0.8% Ca and 0.13% P did not develop hypercalcemia whereas the UBX cockerels fed this diet developed slight significant hypercalcemia after 17 to 21 days. In Experiment I, SHAM cockerels fed the diet containing 2.4% Ca and 0.13% P developed mild, chronic hypercalcemia (12.7 mg./lOO ml.) with a plasma phosphorus of 3.03 mg. P/100 ml., whereas the UBX cockerels fed the same diet developed severe hypercalcemia (16.0 mg./100 ml.) and hypophosphatemia, 1.68 mg. P/100 ml. In Experiment 2 the following plasma values were observed after 17 days of consuming the experimental diets: SHAM fed 2.4% Ca and 0.13% P had 10.6 mg. Ca/100 ml. and 3.59 mg. P/100 ml., whereas UBX fed the same diet had 12.8 mg. Ca/100 ml. and 2.24 mg. P/100 ml. The UBX fed 2.4% Ca and 0.33% P for 17 days had plasma values of 10.8 mg. Ca/100 ml. and 4.48 mg. P/100 ml. It is concluded that the presence of the ultimobrancial glands are essential to the regulation of plasma calcium and phosphorus in chickens which consume high calcium-low phosphorus diets.
ULTIMOBRANCHIALECTOMIZED CHICKENS
tained 0.4% available phosphorus but not when the diet contained 0.6% available phosphorus (Shane and Young, 1969, Shane et al., 1969). For chickens 8 to 22 weeks of age the dietary requirement is approximately 0.8% calcium and 0.4% available phosphorus (N.R.C., 1971). Brown et al. (1970) reported that UBX growing chicks fed a diet containing 1.03% calcium and 0.74 phosphorus had lower serum phosphorus values than did sham operated controls.
MATERIALS AND METHODS Animals. Pilch-Dekalb cockerels, 16 to 22 weeks of age, were maintained in individual cages in a ventilated windowless room, with 16 hours of artificial light each day. Room temperature was 21° C. Feed and water were available ad libitum. Diets. The basal diet (Table 1) contained soybean meal and yellow corn supplemented with sufficient vitamins and minerals (except for calcium and phosphorus) to meet or exceed the 1971 National Research Council (N.R.C.) recommended nutrient requirements. The diet contained 2 times the N.R.C. requirement for vitamin D 3 . The corn and soybean meal were obtained from large stocks each of which had been blended in order to insure that all samples taken for diet formulation during the course of these experiments would have the same chemical composition. The contributions of dietary calcium and phosphorus from the corn and soybean meal were estimated from standard tabular values for these feedstuffs (Scott et al., 1969). The combination of corn plus soybean meal in the basal diet contributed 0.09% calcium, 0.3% total phosphorus, and 0.13% available phosphorus. Available phos-
TABLE 1.—Composition of the basal diet Percent Ingredients of diet Soybean meal (48.5% protein) 30IKJ Yellow corn 61.40 Vitamin premix' 1.00 Choline CI 0.20 D,L-Methionine 0.30 Cottonseed oil 2.00 Ethoxyquin2 + Mineral Mix3 1.61 CaC0 3 2.00 KH 2 P0 4 0.88 Glucose monohydrate 0.61 'Vitamin premix provides in mg./kg. of diet: D-Ca pantothenate 30, niacin 60, thiamine HC1 15, riboflavin 15, pyridoxine HC1 8, folic acid 6, menadione NaHS0 3 3, D-biotin 0.6, vitamin E (276 I.U./g.) 360, vitamin A (325 I.U./mg.) 15.4, vitamin D 3 (200 I.U./mg.) 5.0, vitamin B12 (132 mg./kg.) 272, glucose H 2 0 9,210. 2 Ethoxyquin is 6-ethoxy-l, 2-dihydro-2, 2, 4,trimethyl quinoline, an antioxidant manufactured by Monsanto Chemical Co., St. Louis, Mo., added at 125 mg./kg. of diet. 3 Mineral mix provides in g./kg. diet: NaHC0 3 6.5, NaCl 5.0, MgC03 3.0, FeSO • 7 H 2 0 0.71, MnS0 4 H 2 0 0.33, ZnS0 4 • 7 H 2 0 0.46, CuS0 4 • 5 H 2 0 0.07, Ca(I0 3 ) 2 • 6 H 2 0 0.01. phorus is organic plus inorganic phosphorus from all dietary ingredients but excluding the plant seed phytic acid phosphorus which is indigestible by the chickens (Scott et al., 1969). The K H 2 P 0 4 i n the basal diet provided 0.2% inorganic phosphate. The basal diet thus contained 0.33% available phosphorus. Decreases in dietary phosphorus content were made by substituting glucose for K H 2 P 0 4 . The basal diet supplied 0.8% calcium from C a C 0 3 . The calcium content of the diet was increased by adding 4 g. of CaCO 3 /100 g. of diet. This produced a diet containing 2.4% calcium. In order that the ratio of energy to other nutrients not be disturbed, the additional C a C 0 3 was added to the entire diet rather than substituted for glucose. Surgical Procedure. The endogenous source of calcitonin in the chicken is in the ultimo-
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The purpose of our studies was to determine whether or not the ultimobranchial gland plays a role in the regulation of plasma calcium and phosphorus in cockerels consuming high calcium-low phosphorus diets.
389
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J. D . GARLICH AND D . M .
Blood Collection and Analysis. Heparinized blood samples were obtained from the wing 4. Hyfrecator: manufactured by the Birtcher Corp. Medical Div. 4371 Valley Road, Los Angeles, Calif. 90032.
vein and the plasma was separated by centrifugation. Plasma phosphate was determined by the procedure of Goldenberg and Fernandez (1966). Plasma calcium was determined by the following modification of the fluoremetric method of Kepner and Hercules (1963). Ten to twenty |xl. of plasma were added directly to 5 ml. of a solution containing 7 mg. calcein/liter of 0.8N KOH in clear polystyrene culture tubes. Fluorescence was then determined. Statistical Analysis. Data were analyzed for differences between control and treated groups using a 2-tailed t-test. Values in the tables indicate the mean ± standard error (SE). Experiment 1. Establishment of a Dietary Phosphorus Level which Results in Hypercalcemia in 16 to 23 Week Old Cockerels Fed High Calcium Diets. The cockerels were 16 weeks of age at the beginning of the experiment. There were 10 cockerels in each of 4 groups: sham operated (SHAM) and ultimobranchialectomized (UBX) groups were fed diets containing either 0.8% or 2.4% calcium. The four groups were designated 0.8-S, 0.8-UBX, 2.4-S, and 2.4-UBX. The experiment was conducted over 43 days during which the dietary phosphorus content was altered several times as indicated in Tables 2 and 3. Experiment 2. Time Course of Development of Hypercalcemia and Hypophosphatemia in Cockerels Fed High Calcium-Low Phosphorus Diets. Fifty cockerels 16 weeks of age which had been either UBX or sham operated were divided into five groups of 10 each. During the pre-experimental period of seven days all five groups were fed the basal diet which contained 0.8% calcium and 0.33% available phosphorus. On the subsequent experimental period of 17 days the groups were fed the following diets and given
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branchial (UB) glands not the thyroid glands (Copp et al., 1967; Tauber, 1967; Hoyt et al., 1972). The technique for surgical removal of each pair of UB glands was conducted under pentobarbital anesthesia according to the following modification of the method of Garlich (1971). The Hyfrecator 4 was used to cut much of the fascia which held the UB gland. The gland could then be grasped with a forceps, and gently manipulated such that a curved mosquito forceps could be used to clamp the tissue which lay between the UB gland and the jugular vein. A micro-dissecting scissor with pencil grip handle was used to excise the gland. The remaining severed tissue was cauterized with the Hyfrecator to destroy any remaining UB tissue and seal blood vessels prior to releasing the forceps. Sham operations were conducted by the same procedure except that the UB glands were exposed and gently manipulated but otherwise left intact. The cockerels were 12 to 15 weeks of age when operated upon. The birds were allowed to recover for at least one week before beginning the experiments. During this time they were fed a commercial poultry growing feed containing 1% calcium and 0.6% available phosphorus. Upon termination of the experiment the cockerels were necropsied with the aid of a dissecting scope for any visible sign of unremoved UB tissue. The area surrounding the UB and parathyroid glands was free of adipose tissue in this variety of chicken. The parathyroids and the presence or absence of UB tissue could be readily ascertained. The results from 2 out of a total of 50 cockerels were not included because UB tissue was identified or suspected upon necropsy.
BRYANT
11.28** ±0.18
5.94 ±0.32
11.21 ±0.17
11 04*** ±0.19
0.8-UBX
4.08 ±0.35
10.55 ±0.07
10.3 ±0.0
10.4 ±0.2
16.0 ±0.8
12.7 ±0.3
C
33
1 The numbers indicate the day of the experimental period on which plasma Ca or P was determine mark the duration of feeding a given % of dietary P. 2 Each group consisted of 8 to 10 cockerels except after day 38 Group 0.8-S had 6 and 0.8-UBX had 7. 3 Mean ± SE. For a given day, means followed by notation are significantly different from their *** = P < 0.05, 0.01, 0.001, respectively).
3.34 ±0.27
10.59 ±0.14
0.13% P 10.43 ±0.17
5.88 ±0.31
11.14 ±0.17
9.77 ±0.11
0.8-SHAM
1.68*** ±0.20
12.74 ±0.41
P
29
12.81 ±0.77
Ca
27 0.13% P
3.74* ±0.31
11.23 ±0.19
11.33*** ±0.19
2.4-UBX
Ca
22
Days 1
3.03 ±0.26
0.20% P
16
11.73 ±0.51
12
11.11 ±0.38
P
12
4.93 ±0.40
Ca
11.48 ±0.17
Ca
10.313 ±0.13
Group 2
8 0.33% P '
2.4-SHAM
0
TABLE 2.—Experiment 1. Plasma calcium and phosphorus concentrations (mg./lOO ml.) in UBX an phosphorus content at two dietary calcium levels (0.8 and 2.4%
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J. D. GARLICH AND D. M. BRYANT
TABLE 3.—Experiment 2. Plasma calcium and phosphorus concentrations in UBX or SHAM operated cockerels fed diets of different calcium/phosphorus ratios Pre-exp., 1 days -7 Group 2
Experimental period, days 4
0
Ca, mg ./100 ml.
8
12
17
Ca, mg./lOOml.
Diet C a / P
9.78 3 ±0.10
10.66 ±0.19
2.4/0.13
10.41 ±0.33
11.04 ±0.24
11.09 ±0.16
10.55 ±0.21
2.4-UBX
10.23* ±0.18
11.49** ±0.18
2.4/0.13
11.48 ±0.42
11.75 ±0.50
12.69** ±0.47
12.81*** ±0.35
2.4-UBX, 0.33P
10.14* ±0.13
11.54** ±0.20
2.4/0.33
10.71 ±0.20
10.94 ±0.25
10.44** ±0.23
10.82*** ±0.14
0.8-SHAM
10.00 ±0.19
10.36 ±0.24
0.8/0.13
10.72 ±0.26
10.31 ±0.19
10.13 ±0.13
10.07 ±0.20
0.8-UBX
10.49* ±0.09
11.45** ±0.21
0.8/0.13
11.04 ±0.17
10.70 ±0.18
10.65 ±0.23
11.24*** ±0.21
2.4-SHAM
5.363 ±0.31
5.51 ±0.21
2.4/0.13
5.15 ±0.13
3.84 ±0.24
3.44 ±0.22
3.59 ±0.21
2.4-UBX
6.07 ±0.23
5.51 ±0.21
2.4/0.13
4.76 ±0.29
2.89* ±0.27
2.40** ±0.21
2.24*** ±0.21
2.4-UBX, 0.33P
5.52 ±0.18
5.29 ±0.15
2.4/0.33
5.26 ±0.14
4.81** ±0.15
4.43** ±0.22
4.48** ±0.17
0.8-SHAM
5.96 ±0.15
5.31 ±0.27
0.8/0.13
4.88 ±0.23
4.13 ±0.33
4.29 ±0.31
4.22 ±0.36
0.8-UBX
5.35* ±0.18
5.11 ±0.17
0.8/0.13
4.78 ±0.26
4.13 ±0.36
4.09 ±0.37
3.69 ±0.29
P, mg. /100 ml.
P, mg./lOOml.
'All cockerels were fed a diet containing 0.8% Ca/0.3% P during pre-exp. period and then fed diets with the Ca/P ratios indicated on days 1 to 17. 2 Each group consisted of 8 to 10 cockerels except Group 2.4-UBX-0.33 on days 8 to 12 had 7, and3 on day 17 had 5. Means ± SE. For a given day, means followed by notation are significantly different (*, **,*** = P < 0.05, 0.01, 0.001, respectively) from their respective control. The 2.4 UBX-0.33 was compared to 2.4-UBX.
the respective designations: sham operated fed 0.8% Ca, 0.13% P (0.8-S), UBX fed 0.8% Ca, 0.13% P (0.8-UBX), sham operated fed 2.4% Ca, 0.13% P (2.4-S) UBX fed 2.4% Ca, 0.13% P (2.4-UBX) and UBX fed 2.4% Ca and 0.33% P (2.4-UBX-0.33). Plasma calcium and phosphorus were determined during the pre-experimental period on days designated - 7 and 0, and on days 4, 8, 12, and 17 of the experimental period. At the beginning of the experiments each treatment group contained 10 cockerels. During the course of the experiments a few cockerels were diagnosed as having Marek's disease and were removed. The actual
number of cockerels studied are indicated in footnotes to the tables. RESULTS Table 2 shows the plasma calcium and phosphorus concentrations of cockerels in experiment 1. Initially the UBX cockerels had significantly higher plasma calcium concentrations relative to the sham operated controls. All cockerels had been consuming a commercial broiler grower diet containing 1.0% calcium and 0.6% available phosphorus. Eight days after changing to the experimental diets plasma calcium concentrations were the same for all 4 groups of cockerels. On day
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2.4-SHAM
ULTIMOBRANCHIALECTOMIZED CHICKENS
mental period when the diet contained 0.33% P, and again 17 days after beginning to consume the diet containing 0.13% phosphorus. Throughout the experiment the plasma calcium concentrations were consistently higher in the 2.4-UBX and 0.8-UBX relative to their sham operated controls although the differences were not always statistically significant. The plasma phosphorus concentration (Table 3) of the 2.4-UBX was significantly lower (P < 0.05) than that of 2.4-S 8 days after beginning consumption of the 0.13% P diet, and remained significantly lower (P < 0.01) throughout the remainder of the experiment. The plasma phosphorus concentrations of the 0.8-UBX, 0.8-S, and 2.4-S decreased from pre-experiment concentrations but did not differ significantly from each other at the same points in time. The plasma phosphorus concentrations of 2.4-UBX-0.33 P fed 0.33% dietary phosphorus throughout remained high and was significantly greater (P < 0.01) than the 2.4-UBX fed 0.13% dietary phosphorus on days 8, 12, and 17. Individual body weight gain was determined during the course of the experiments. There were no significant differences in average body weight gain among any of the treatment groups in either experiment. DISCUSSION The results of these experiments indicated that severe chronic hypercalcemia and concomitant hypophosphatemia developed in UBX but not sham-operated chickens fed high calcium-low phosphorus diets. Our experimental approach differed in at least two aspects from that of most other investigations of chickens. One, we modified the dietary proportions of calcium and phosphorus, and two, we conducted a longitudinal study which monitored the changes in plasma calcium and phosphorus over a period of several weeks. Most other investigations have been concerned with the short term, acute effects of
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12 the dietary phosphorus content was reduced to 0.20% and then on day 22 dietary P was reduced to 0.13%. By day 33 the 2.4-UBX had significantly higher plasma calcium concentrations than the 2.4-S (16.02 vs. 12.71 mg./lOO ml.). The 2.4-S showed increasing plasma calcium concentrations as dietary phosphorus was decreased. On day 35 the dietary P of 2.4-UBX and 2.4-S was increased to 0.33%. By day 43 plasma calcium of both groups had declined. The 2.4-S had a normal plasma calcium concentration (10.27 mg./lOO ml.) but the 2.4-UBX were still significantly hypercalcemic, 13.44 mg./lOO ml. (P < 0.001). Relative to the 0.8-S controls, the 0.8-UBX had significantly higher plasma calcium on days 0, 16, and 43. When the diet contained 0.13% phorphorus the 0.8-UBX appeared to develop an increasing plasma calcium concentration which was significantly different from the 0.8-S by day 43. The plasma P (Table 2) of 2.4-UBX was significantly lower than 2.4-S at all dietary phosphorus levels. The 2.4-UBX developed severe hypophosphatemia by day 29. After increasing dietary phosphorus to 0.33% on day 35, plasma P of both groups increased but a significant difference was still evident on day 41. The 0.8-S and 0.8-UBX continued to receive the 0.13% P diet. The 0.8-UBX did not show a significantly lower plasma P relative to 0.8-S on any given day of the experiment. In experiment 2, the plasma calcium concentrations (Table 3) of 2.4-UBX was significantly greater than 2.4-S 12 days after the dietary phosphorus was reduced from 0.33 to 0.13%. The plasma calcium concentration of the 2.4-UBX-0.33 P which consumed a diet containing 0.33% phosphorus throughout the experiment did not become elevated and on days 12 and 17 was significantly lower than 2.4-UBX. The plasma calcium concentrations of 0.8-UBX relative to 0.8 S were significantly elevated during the pre-experi-
393
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J. D. GARLICH AND D. M. BRYANT
A possible explanation of our results is that the absence of the UB glands and consequently endogenous calcitonin in the UBX group fed the high calcium-low phosphorus diet resulted in failure to maintain a sufficiently elevated plasma and kidney phosphorus concentration. The suppression of
hydroxylation of 25 HCC was reduced and the resulting increase in 1-25 DHCC increased intestinal calcium absorption and plasma calcium concentration. The maintenance of high plasma phosphorus in our 2.4-UBX-0.33 P group in Experiment 2 resulted in normal plasma calcium concentration. This observation is also in accordance with the work of Tanaka and associates (Tanaka and DeLuca, 1973; Tanaka et al., 1973). ACKNOWLEDGEMENTS The authors are grateful for the advice of Dr. C. H. Hill, Dr. P. B. Hamilton and for the technical assistance of Mrs. Carole Morris. REFERENCES Brown, D. M., D. Y. E. Perey and J. Jowsey, 1970. Effects of ultimobranchialectomy on bone composition and mineral metabolism in chickens. Endocrinology, 87: 1282-1891. Chan, A. S. J. D. Cipera and L. F. Belanger, 1969. The ultimobranchial gland of the chick and its response to a high calcium diet. Rev. Can. Biol. 28: 19-31. Cooper, C. W., L. J. Deftos and J. T. Potts, Jr., 1971. Direct measure of in vivo secretion of pig thyrocalcitonin by radioimmunoassay. Endocrinology, 88: 747-754. Copp, D. H., D. W. Cockcroft and Y. Kueh, 1967. Ultimobranchial origin of calcitonin. Hypocalcemic effect of extracts from chicken glands. Canad. J. Physiol. 45: 1095-1099. DeLuca, H. F., 1972. The functional metabolism of vitamin D 3 . In: Calcium Parathyroid Hormone, and the Calcitonins, Ed. R. V. Talmage and P. L. Munson. Excerpta Medica, Amsterdam, p. 221-235. Garlich, J. D., 1971. A technique for the surgical removal of the ultimobranchial glands from the domestic fowl. Poultry Sci. 50: 700-702. Goldenberg, H., and A. Fernandez, 1966. Simplified method for the estimation of inorganic phosphorus in body fluids. Clinical Chem. 12: 871-876. Gonnerman, W. A., R. P. Breitenbach, W. F. Erfling and C. S. Anast, 1972. An analysis of ultimobranchial gland function in the chicken. Endocrinology, 91: 1423-1429. Gray, T. K., and P. L. Munson, 1969. Thyrocalcitonin: evidence for physiological function. Science, 166: 512-513.
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calcitonin or with one exception (Brown et al., 1970) have not included dietary calcium and phosphorus as experimental variables. Our results indicate that the ultimobranchial glands are involved in the regulation of both plasma calcium and phosphorus concentrations in the chicken. The administration of exogenous calcitonin will be required to establish whether or not ultimobranchial calcitonin is indeed responsible for the differences observed under our experimental conditions. Whether the primary effect of the absence of the UB glands in our experiments was on calcium or phosphorus is unknown. Talmage et al. (1973) have clearly shown that in the thyroidectomized rat calcitonin modulates plasma phosphate concentration. Tanaka and Deluca (1973) and Tanaka et al. (1973) reported that the phosphate concentration of the kidney tuble of the rat correlates well with the 1-a hydroxylation of 25 hydroxycholecalciferol (25 HCC) to la-25dihydroxycholecalciferol (1-25 DHCC), the compound which is considered to be the metabolite most responsible for both intestinal calcium absorption and bone mineral resorption (DeLuca, 1972). Low plasma and kidney phosphate concentrations coincided with increased synthesis of 1-25 DHCC whereas high plasma phosphate concentrations were correlated with decreased synthesis. It was also shown that kidney phosphorus concentration was influenced by dietary phosphorus. They hypothesized that calcitonin may increase kidney phosphorus content and thereby suppress synthesis of 1-25 DHCC. Previously, Olson et al. (1972) had shown that calcitonin inhibits vitamin D-induced intestinal calcium absorption.
ULTIMOBRANCHIALECTOMIZED CHICKENS
Nutrition of the Chicken, M. L. Scott and Assoc. Publishers, Ithaca, N.Y. Shane, S. M., and R. J. Young, 1969. Renal and parathyroid changes produced by high calcium intake in growing pullets. Avian Dis. 13: 558-567. Shane, S. M., R. J. Young and L. Krook, 1969. Metabolic disturbances in replacement pullets produced by high calcium diets. Proceedings of the 1968 Cornell Nutrition Conference for Feed Manufacturers. Department of Poultry Science, Cornell University, Ithaca, N.Y. p. 126-131. Talmage, R. V., L. A. Whitehurst, and J. J. B. Anderson, 1973. Effect of calcitonin and calcium infusion on plasma phosphate. Endocrinology 92: 792-798. Tanaka, Y., and H. F. DeLuca, 1973. The control of 25-hydroxyvitamin D metabolism by inorganic phosphorus. Arch. Biochem. Biophys. 154: 566-574. Tanaka, Y., H. Frank and H. F. DeLuca, 1973. Intestinal calcium transport: stimulation by low phosphorus diet. Science 181: 564-566. Tauber, S. D., 1967. The ultimobranchial origin of calcitonin. Proc. Nat. Acad. Sci. U.S.A. 58: 16841687. Urist, M. R., 1967. Avian parathyroid physiology: Including a special comment on calcitonin. Amer. Zool. 7: 883-895.
NEWS AND NOTES (Continued from page 349) Chang, T. S., M. S. Rheins and A. R. Winter, 1959. The significance of the bursa of Fabricius in antibody production. 3. Resistance to Salmonella typhimurium infection. Poultry Sci. 38: 174-176. EUROPEAN SYMPOSIUM ON POULTRY MEAT The second European Symposium on Poultry Meat will be held May 12-16, 1975, at the Bilderberg Conference Hotel, Oosterbeek, The Netherlands. It is being organized by Sub-Committee 4B (Poultry Meat Quality) of the European Federation of Branches of the World's Poultry Science Association. Official language of the Symposium will be English. Attendance is open to all interested in quality of poultry meat. The theme of the program is: Influences on quality of poultry meat. The program will have plenary, contributed papers and focal topic sessions.
The three plenary sessions are: Quality (definition, methods of measurement, interpretation of data); Influence of production factors on quality; and Influence of processing factors on quality. The focal topic and sessions will be on: Turkey meat, Sensory testing, Mechanically deboned meat, Scalding, Pesticides and other chemicals in poultry meat, Veterinarian inspection, and Microbiological aspects of quality. Further information may be obtained from the Symposium Secretariat: Dr. B. Erdtsieck, Ruitersmolenweg 21, Beekbergen, The Netherlands. CONGRESS OF PACIFIC SCIENCE ASSOCIATION The Thirteenth Congress of the Pacific Science Association will be held in Vancouver, British Columbia, Canada, on the campus of the University of British
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Hirsch, P. F., 1971. Thyrocalcitonin and its role in calcium regulation in mammals. J. Exp. Zool. 178: 139-149. Hoyt, R. F., A. H. Tashjian, Jr. and D. W. Hamilton, 1972. Distribution of thyroid, parathyroid and ultimobranchial hypocalcemic factors in birds. 1. Thyroid and ultimobranchial calcitonins in pigeons and pullets. Endocrinology, 91: 770-783. Kepner, B. L.,and D. M. Hercules, 1963. Fluoremetric determination of calcium in blood serum. Anal. Chem. 35: 1238-1240. Kraintz, L., and K. Intscher, 1969. Effects of calcitonin on the domestic fowl. Can. J. Physiol. Pharm. 47: 313-315. Mueller, G. L., C. S. Anast and R. P. Breitenbach, 1970. Dietary calcium and ultimobranchial body and parathyroid gland in the chicken. Am. J. Physiol. 218-1722. National Research Council, 1971. Nutrient requirements for domestic animals. 1. Nutrient requirements for poultry. 6th ed., National Academy of Sciences, Washington, D.C. Olson, E. B., Jr., H. F. DeLuca and P. T. Potts, Jr., 1972. Calcitonin inhibition of vitamin D-induced intestinal calcium absorption. Endocrinology, 90: 151-157. Scott, M. L., M. C. Nesheim and R. J. Young, 1969.
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