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Potassium Deficiency in the Adult Male Chicken
Potassium Deficiency in the Adult Male Chicken EDUARDO CHAVEZ1 and F. H. KRATZER Department of Avian Sciences, University of California, Davis, California 95616 (Received for publication August 3, 1978)
1979 Poultry Science 58:652-658 INTRODUCTION T h e need for potassium in growing chickens has been s h o w n b y Ben-Dor ( 1 9 4 1 ) , Gillis ( 1 9 4 8 ) , and R i n e h a r t et al. ( 1 9 6 8 ) . Leach et al. ( 1 9 5 9 ) d e m o n s t r a t e d a definite interrelationship b e t w e e n potassium and t h e protein cont e n t of t h e diet. T h e potassium r e q u i r e m e n t for growing chicks has been given as .2% of t h e diet b y t h e National Research Council (Sunde et al., 1 9 7 7 ) . Leach ( 1 9 7 4 ) found reduced egg prod u c t i o n , weakness, and d e a t h in potassium deficient laying hens a n d d e t e r m i n e d t h e requirement t o be . 1 % of t h e diet. There has been n o work reported studying t h e need for potassium in the adult male chicken. The present s t u d y investigated t h e need for potassium b y adult male chickens by feeding a low and an a d e q u a t e potassium diet for an 1 1 week period, b y s t u d y i n g t h e potassium balance of these birds at various periods during t h e exp e r i m e n t , and by d e t e r m i n i n g t h e utilization of radioactive potassium b y these birds at t h e end of t h e e x p e r i m e n t a l period. METHODS T w e n t y a d u l t male Single C o m b White Leghorn chickens, 31 weeks of age, were housed in individual cages and fed individually either a potassium-deficient diet (Table 1, .02% p o t a s -
1 Present address: University of Guelph, Guelph, Ontario, Canada.
sium) or t h e same diet s u p p l e m e n t e d with . 3 % potassium as potassium c a r b o n a t e . After 7 weeks of t h e experimental period, t h e calcium c a r b o n a t e was eliminated from t h e e x p e r i m e n tal diets and dicalcium-phosphate reduced from 1.4% t o .6%. This reduced t h e t o t a l calcium c o n t e n t of t h e diet from .4 t o .14% of t h e diet which was still in excess of t h e need for calcium as r e p o r t e d by Norris et al. ( 1 9 7 2 ) . T o t a l excreta from four birds of t h e p o t a s sium-supplemented group and from five birds of t h e potassium-deficient g r o u p were collected in stainless steel trays for a period of 2 4 hr after 2, 4, 5, and 8 weeks of t h e e x p e r i m e n t a l period. Each collection was analyzed for s o d i u m , p o t a s sium, magnesium, and calcium b y a t o m i c a b sorption s p e c t r o p h o t o m e t r y . After an 11-week experimental period, a 24hr radio-isotopic e x p e r i m e n t was c o n d u c t e d with all t h e birds. Potassium-42 was used as p o tassium chloride in water with specific activity of .05 m C i / m g potassium. Each rooster was injected in t h e brachial vein with an average dose of 6.69 juCi of p o t a s s i u m - 4 2 / 1 0 0 g b o d y weight (range 5.65 t o 7.88). Two roosters from each dietary t r e a t m e n t were killed a p p r o x i m a t e l y 1, 2, 4 , 8, and 2 4 hr after being injected with t h e radioisotope. Blood samples in triplicate, t o t a l excretion, and tissue samples including skin, muscle, heart, liver, intestine, and b o n e in triplicate were collected from each bird and c o u n t e d in an a u t o m a t i c g a m m a c o u n t e r (Baird A t o m i c Iso/Matic Model 707) with an efficiency of 30% d e t e r m i n e d with a g a m m a reference source of
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ABSTRACT Adult male chickens, which were maintained on a low dietary potassium intake for 11 weeks showed no gross abnormalities, but had significantly reduced feed intake and losses of body weight. Adult male chickens had a physiological capacity to increase the biological half life of their body potassium from 18 to 134 days when the dietary potassium was reduced from .32 to .02%. However, the deficient birds were unable to balance their intake with the excretion because of the obligatory loss of potassium. The relative specific activity of different tissues in adult male chickens determined at different time intervals after the intravenous injection of potassium-42 indicated that the plasma pool potassium had the highest turnover rate of potassium in the body. In decreasing order, it was followed by the skin, heart, liver, intestine, bone, and muscle. The daily balance of potassium in adult male chickens maintained under optimum and sub-optimum dietary potassium intake gave an estimated minimum requirement for this element of .06% of the diet.
POTASSIUM FOR ADULT MALE CHICKENS TABLE 1. Potassium deficient diet for adult male chickens Ingredient
(g/kg)
Corn starch Glucose monohydrate a Cellulose 0 Isolated soybean protein c Soybean oil CaHP04-2H20 CaC0 3 Mineral mixture*! Vitamin mixture e DL-methionine
400 230 129.4 160 40 14 2.6 10 10 4
%•
Cesium 137. Total excreta after injection with potassium-42 were collected individually, brought to an exact volume with 1% nitric acid, homogenized in an electric mixer, and sampled in triplicate for counting. Subsequently, total excreta samples were collected, dried, ashed in a muffle furnace at 600 C, and analyzed to determine total potassium content. Counts were recorded with the time of counting and the hour of the day for each individual sample, and later corrected for decay (half life, 744 min). Total counts were finally expressed as counts/ min/g of sample. Analysis of potassium content allowed the calculation of specific activity in counts/min/mg potassium.
RESULTS Deficient roosters maintained their body weight unaffected by the deficiency of potassium until the 4th week of the experimental period (Table 2). From the 5th to the 11th experimental week, body weight was significantly reduced in comparison to the control roosters.
The control birds showed a slight gain in body weight (4.65%) during the entire experiment. Thus, the final body weight difference between deficient and control birds was due to the decrease in body weight in the deficient, and, to a lesser degree, a small increase in the body weight of the control birds. Average daily feed intake for weekly periods for roosters fed the potassium-deficient diet was unaffected for the first four experimental weeks (Table 2). Subsequently, there was a significant reduction in daily feed intake in the deficient birds during the 5th, 6th, 10th, and 11th weeks compared to the control birds. Overall there was a significant decrease (p=<.005) in daily feed intake of the deficient males compared to the potassium-supplemented birds. The abrupt reduction in feed intake in both groups observed during the first experimental week could be due to the change in type of feed. The most striking difference in potassium excretion between supplemented and deficient adult chicken males, was the reduction in potassium loss through the feces and urine in the deficient chickens (Table 3). The potassium excretion was relatively constant in each of the groups for the three experimental periods shown, but the excretion from the deficient birds was approximately one tenth that of the potassium-supplemented chickens. The reduced calcium excretion in the last balance trial was due to the lowering of the calcium level in the diets. The potassium content of the blood plasma of potassium-deficient roosters was significantly lower at the end of the experiment (Table 4). The skin of the deficient birds had less dry matter, but there was no difference in potassium content between the potassium-deficient and supplemented groups. Heart and muscle weights from deficient chickens were slightly less than the controls but there was no difference in potassium content between the two groups. The intestine and liver from deficient chickens contained more potassium than the controls. There were no differences in the composition of the bone between the two groups. The excretion of potassium-42 (Table 5) was far greater in the potassium-supplemented chickens than in those deficient in potassium. From these data by using the chi square method of regression analysis, the biological half life of potassium was found to be 18 days for the supplemented birds and 134 for those
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Cerelose. Solka floe from Brown Co., Berlin, NH. c Ralston Purina RP-100. d Supplied in g/kg diet: NaCl, 5.0; MgSO„, 2.5; MnSO„-H20, .2; FeS0 4 -7H 2 0, .4; CuS0 4 -5H 2 0, .05; Co acetate.4H 2 0, .01; Nal, .004; A1 2 (S0 4 ) 3 18H 2 0, .1; Na 2 Mo0 4 -2H 2 0, .009; ZnO, .1; Na selenite, .0007; and NaF, .009. Supplied per kilogram diet: vitamin A 2,275 IU vitamin D3, 325 ICU; vitamin E, 88 IU; menadione, 3 mg; thiamine'HCl, 10 mg; riboflavin, 10 mg; Ca pantothenate, 30 mg; niacin, 100 mg; pyridoxine-HCl, 10 mg; D-biotin, .2 mg; folic acid, 5 mg; vitamin B, 2 , 30 meg; butylated hydroxytoluene, .5 mg; and inositol, 1 b
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POTASSIUM FOR ADULT MALE CHICKENS
655
TABLE 3. Analysis of total excreta collected in 24 hr in adult chicken males at different times during the experimental period
2 weeks
8 weeks
4 77 + 4a 42 ± 3 17.0 ± .62 2.22 ± .09 41.06 ± 2.80 1 3 . 0 7 + .12 6.81 ± .41 7.12 + .65 3.54 ± .11 19.08 + .36
4 89 ±8 58 ±5 1 8 . 2 4 + 1.06 2 . 0 3 + .13 31.79 ± 1.33 11.17 ± .53 7.14 ± 1.05 6.28 ± .84 2.52 ± .10 34.69 ± 2.66
4 71 45 14.69 1.01 34.11 6.86 6.04 5.85 2.72 2.13
± 7 ± 7 ± .96 ± .10 ± 3.82 ± .43 + .43 ± .78 + .31 ± .13
5 67 +13 38 ±8 16.5 + 2.34 1.83 ± .40 4 7 . 9 8 ± 8.5 10.79 ± .84 6.42 ± .87 .65 ± .10 3 . 4 8 + .46 17.96 ± 2.60
5 73 36 13.87 1.18 39.79 8.52 4.09 .68 2.00 20.33
5 69 50 14.55 .60 30.87 4.09 4.01 .62 2.58 2.71
+ 5 ± 6 + .90 ± .05 ± 3.31 ± .20 ± .38 ± .04 + .21 ± .26
±5 +5 ± 1.31 ± .11 ± 2.60 ± .10 ± .68 ± .10 ± .13 ± 2.51
aMean ± SEM.
deficient in potassium. Turnover rates were 3.86% per day for the supplemented and .5% per day for the deficient birds and the turnover time was 25.9 days compared with 193.7 days for those deficient. The specific activity of the plasma at 1 hr was 1/140 of the calculated value after the intravenous injection. The ratio of specific activities of the tissue and organs compared with the specific activity of the plasma are shown in Table 6. Muscle was the only tissue which did not achieve 100% interchange even after 24 hr. The results obtained from the potassium-deficient roosters were similar in general, however, the liver, intestine, and bone samples of the deficient roosters appeared to have lower and more stable relative specific activities than the supplemented controls. DISCUSSION The response of adult male chickens to a dietary potassium deficiency was different for the different organs and tissue structures. Thus, while the pectoral muscle, intestine, liver, and
bone maintained a normal hydration state, skin and heart suffered hyperhydration. Without taking into account this water balance modification, the ash content of the skin, muscle, intestine, heart, and bone were maintained at normal levels, while in the liver there was a slight but significant increase in ash content. This increase in ash content of the liver can be explained both by the slight increase in dry matter and a significant increase in potassium content. Neither muscle, or intestine showed any significant alteration in dry matter or ash content with the potassium-deficient diet, but muscle significantly decreased and intestine significantly increased in potassium content. This strongly indicates that electrolyte compensation was complete. The heart hyperhydration in response to a dietary potassium deficiency appears as the only adjustment made to maintain the total ash and potassium concentration at normal levels. Exactly the same situation held for the skin. The overall picture observed in adult male chickens deficient in potassium suggested that survival was achieved fundamentally
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Potassium supplemented roosters Number of individual feces collected Feed intake/day during collections, g Total excretion fresh weight, g Total dry matter excreted, g Total ash excreted, g Dry matter, % Ash in dry matter, % Total sodium excreted, mEq/24 hr Total potassium excreted, mEq/24 hr Total magnesium excreted, mEq/24 hr Total calcium excreted, mEq/24 hr Potassium deficient roosters Number of individual feces collected Daily feed intake day of collection, g Total excretion fresh weight, g Total dry matter excreted, g Total ash excreted, g Dry matter, % Ash in dry matter, % Total sodium excreted, mEq/24 hr Total potassium excreted, mEq/24 hr Total magnesium excreted, mEq/24 hr Total calcium excreted, mEq/24 hr
Experimental period 5 weeks
CHAVEZ AND KRATZER
656
TABLE 4. Dry matter, ash, and potassium content of some tissues and organs of adult male chickens fed potassium supplemented and deficient diets K-supplemented mean ± SEM a Blood plasma: mEq K/liter
4.51 + .48a
K-deficient mean ± SEM
2.71 ±
.20b
t- test significance
P<.025
48.29 .43 .18 .47
± ± ± ±
1.94 .03 .03 .08
42.02 .43 .18 .47
± 1.51 ± .02 ± .03 ± .08
P<.05 NS NS NS
Heart: Heart weight, g Dry matter, % Ash, % mg K/g sample Potassium, mEq/100 g
12.77 30.41 .98 1.74 4.46
+ + ± ± ±
.83 1.00 .05 .13 .33
10.53 27.34 .97 1.82 4.66
± .74 ± 1.03 ± .04 ± .11 ± .29
P<.05 P<.05 NS NS NS
Muscle: Dry matter, % Ash, % mg K/g sample Potassium, mEq/100 g
27.11 1.17 2.64 6.74
± ± ± ±
.26 .02 .09 .24
27.34 2.23 2.33 5.96
± + + ±
.25 .04 .09 .23
NS NS P<.025 P<.025
Intestine: Dry matter, % Ash, % mg K/g sample Potassium, mEq/100 g
26.70+ 1.26 ± 2.09 ± 5.35 ±
1.18 .02 .06 .16
24.61 1.29 2.37 6.07
± ± ± ±
.37 .01 .08 .20
NS NS P<.025 P<.025
Liver: Dry matter, % Ash, % mg K/g sample Potassium, mEq/100 g
26.39 1.16 1.39 3.56
± ± ± ±
.50 .03 .07 .19
26.72 1.22 1.64 4.19
± ± ± ±
.37 .02 .08 .21
NS P<.05 P<.001 P<.001
Bone: Tibia weight, g Dry matter, % Ash, % Potassium, mEq/100 g
18.42 78.55 34.78 1.11
+ ± ± ±
1.14 .75 1.03 .10
18.22 75.44 34.07 .92
± 1.17 ± 1.45 ± 1.49 ± .11
NS NS NS NS
Ten birds for each treatment were sampled in triplicate for each tissue.
at muscle expense. The total muscle mass was significantly reduced which was reflected in body weight values. Potassium concentration in the muscle was also significantly reduced. Cardiac muscle weight reduction was demonstrated; a significant reduction in the total potassium excretion was, of course, another contributing mechanism in the survival capacity of adult male chickens under potassium deficiency, but it was limited by the obligatory potassium component of the urinary excretion. Finally, the dramatic reduction in the turnover rate of potassium or the immense increase in the biological half life of potassium represents the summation of many adjustments performed at the cellular level for conserving potassium
under a dietary deficiency. Skin and heart tissues showed the highest relative specific activity approximately 1 hr after the injection of potassium-42. Relative specific activities of the intestine, liver, and bone decreased in order. In all of these tissues, the relative specific activity was higher than 1. This fact, however, can hardly represent more than 100% potassium exchange. Neither can the RSA value of greater than 1 be interpreted as an accumulation of the injected labeled potassium in these tissues since this would invalidate the principle that the radioactive element has the same behavior within the organism as the natural one. It was observed that the maximum specific activity of the plasma at about 1 hr
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Skin Dry matter, % Ash, % mg K/g sample Potassium, mEq/100 g
POTASSIUM FOR ADULT MALE CHICKENS
657
TABLE 5. Excretion of potassium 42 at different times after being injected into potassium deficient and supplemented adult male chickens3Potassium deficient
Potassium supplemented Time after injection (min)
K excreted Total (cpm X 10 3 )
Time after injection (min)
Total " 2 K excreted (cpm X 10 3 )
54 87 157 176 295 301 496 497 1424 1425
799.2 499.6 1348.7 2547.5 2407.6 6343.7 3716.3 5264.5 4225.8 4625.4
65 88 157 185 300 302 481 496 1425 1426
30.0 0 189.8 109.8 99.9 289.7 179.8 249.8 259.7 559.4
18 days 3.86%/day 25.9 days
Biological half time of K Turnover rate of K Turnover rate of K
after the isotope injection was about 1/140th of the original value. This shows that the decay was very rapid representing a very fast turnover rate for the potassium in the plasma. The relative specific activity represents a turnover rate of potassium in the respective tissue relative to the turnover rate in the plasma; thus it can be concluded that the plasma pool potassium has the highest turnover rate in the body. The skin has the next highest turnover rate because it
134 days .5%/day 193 days.
reaches the highest relative specific activity about 1 hr after injecting the potassium-42 and its decay was faster than any other tissue. Skin was followed by the heart, liver, intestine, and bone in decreasing order of turnover rates. Uptake of potassium-42 by the muscle was relatively slow and its turnover rate was also very slow. Bone, intestine, and liver were the tissues most responsible for the great reduction in the turnover rate of body potassium observed in
TABLE 6. Relative specific activities for various tissues at different times after injection with 4 2 K Exp. time* minute
SA b plasma
Relative specific activity 0 Skin
Heart
Liver
Intestine
Bone
Muscle
55,710 44,587 40,759 67,770 45,921
7.64 3.54 5.34 2.52 3.64
3.46 2.38 1.45 1.14 1.14
2.85 1.31 1.27 .99 .91
2.91 1.91 1.92 1.75 1.42
1.98 .79 .95 .84 1.40
.57 .42 .43 .45 .64
K-deficient roosters 77 60,164 171 57,259 301 44,796 489 60,860 1426 59,257
7.32 4.36 6.99 3.97 2.09
2.86 1.52 1.89 .94 1.89
1.79 1.19 1.59 .91 1.10
1.75 1.87 2.28 1.52 1.39
1.13 1.46 1.97 2.09 1.32
.45 .33 .88 .36 .56
K supplemented roosters: 76 166 298 496 1425
Time period between " 2 K injection and the death of the bird. Average of two roosters for each time. Specific activity determined (CPM/mg K) in the plasma. Ratio of the SA in the plasma and the SA in the tissue at different time intervals.
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egg contains approximately 100 mg, equivalent to .04% dietary potassium at 60% egg production. REFERENCES Ben-Dor, B., 1941. Requirement of potassium by the chick. Proc. Soc. Exp. Biol. Med. 4 6 : 3 4 1 - 3 4 3 . Fenn, W. O., T. R. Noonan, L. J. Mullins, and L. Haege, 1941/42. The exchange of radioactive K with body K. Amer. J. Physiol. 135:149-163. Gillis, M. B., 1948. Potassium requirement of the chick. J. Nutrition 36:351-357. Hevesy, G., 1948. Radioactive indicators. Interscience Publishers, Inc. New York. Leach, R. M., 1974. Studies on the potassium requirement of the laying hen. J. Nutrition 104:684-686. Leach, R. M., Jr., R. Dam, T. R. Zeigler, and L. C. Norris, 1959. The effect of protein and energy on the potassium requirement of the chick. J. Nutrition 68:89-100. Noonan, T. R., W. O. Fenn, and L. Haege, 1941. The distribution of injected radioactive K in rats. Amer. J.Physiol. 132:474-488. Norris, L. C , F. H. Kratzer, H. J. Lin.A. B. Hellewell, and J. R. Beljan, 1972. Effect of quality of dietary calcium on maintenance of bone integrity in mature White Leghorn male chickens. J. Nutriton 102:1085-1092. Rinehart, K. E., J. C. Rogler, and W. R. Featherston, 1968. Influence of dietary potassium on chick growth, food composition, and blood and tissue composition. Poultry Sci. 47:320—325. Sunde, M. L., J. R. Couch, L. S. Jensen, B. E. March, E. C. Naber, L. M. Potter, and P. E. Waibel, 1977. Nutrient requirement of poultry. Nat. Acad. Sci., Washington, DC.
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the potassium-deficient group of roosters. The turnover rate of the skin, however, appeared to be unaffected. These results are in good agreement with those reported by Noonan et al. (1941) and Fenn et al. (1941/42), but are not in agreement with the interpretation given to them by Hevesy (1948). If the negative potassium balance obtained with the potassium-deficient roosters represents the minimum daily excretion of potassium under this dietary regimen, then this truly represents an obligatory component of the daily requirement. On the other hand, the positive potassium balance obtained with the potassium-supplemented roosters represents the maximal potassium retention for the optimal metabolic activity of birds that are gaining some body weight; this also represents another obligatory component of the daily requirement for potassium. Therefore, the addition of these two components may well be a good estimate of the minimum requirements for potassium for adult male chickens. This value is 45 mg of potassium per day, which represents .06% of the diet assuming feed consumption similar to that of the potassium-supplemented group of birds. This is considerably lower than the potassium requirement for the growing chicken of .2% but is in good agreement with the need for the laying hen of .1% reported by Leach (1974), particularly if it is assumed an
1979 Poultry Science 58:652-658 INTRODUCTION T h e need for potassium in growing chickens has been s h o w n b y Ben-Dor ( 1 9 4 1 ) , Gillis ( 1 9 4 8 ) , and R i n e h a r t et al. ( 1 9 6 8 ) . Leach et al. ( 1 9 5 9 ) d e m o n s t r a t e d a definite interrelationship b e t w e e n potassium and t h e protein cont e n t of t h e diet. T h e potassium r e q u i r e m e n t for growing chicks has been given as .2% of t h e diet b y t h e National Research Council (Sunde et al., 1 9 7 7 ) . Leach ( 1 9 7 4 ) found reduced egg prod u c t i o n , weakness, and d e a t h in potassium deficient laying hens a n d d e t e r m i n e d t h e requirement t o be . 1 % of t h e diet. There has been n o work reported studying t h e need for potassium in the adult male chicken. The present s t u d y investigated t h e need for potassium b y adult male chickens by feeding a low and an a d e q u a t e potassium diet for an 1 1 week period, b y s t u d y i n g t h e potassium balance of these birds at various periods during t h e exp e r i m e n t , and by d e t e r m i n i n g t h e utilization of radioactive potassium b y these birds at t h e end of t h e e x p e r i m e n t a l period. METHODS T w e n t y a d u l t male Single C o m b White Leghorn chickens, 31 weeks of age, were housed in individual cages and fed individually either a potassium-deficient diet (Table 1, .02% p o t a s -
1 Present address: University of Guelph, Guelph, Ontario, Canada.
sium) or t h e same diet s u p p l e m e n t e d with . 3 % potassium as potassium c a r b o n a t e . After 7 weeks of t h e experimental period, t h e calcium c a r b o n a t e was eliminated from t h e e x p e r i m e n tal diets and dicalcium-phosphate reduced from 1.4% t o .6%. This reduced t h e t o t a l calcium c o n t e n t of t h e diet from .4 t o .14% of t h e diet which was still in excess of t h e need for calcium as r e p o r t e d by Norris et al. ( 1 9 7 2 ) . T o t a l excreta from four birds of t h e p o t a s sium-supplemented group and from five birds of t h e potassium-deficient g r o u p were collected in stainless steel trays for a period of 2 4 hr after 2, 4, 5, and 8 weeks of t h e e x p e r i m e n t a l period. Each collection was analyzed for s o d i u m , p o t a s sium, magnesium, and calcium b y a t o m i c a b sorption s p e c t r o p h o t o m e t r y . After an 11-week experimental period, a 24hr radio-isotopic e x p e r i m e n t was c o n d u c t e d with all t h e birds. Potassium-42 was used as p o tassium chloride in water with specific activity of .05 m C i / m g potassium. Each rooster was injected in t h e brachial vein with an average dose of 6.69 juCi of p o t a s s i u m - 4 2 / 1 0 0 g b o d y weight (range 5.65 t o 7.88). Two roosters from each dietary t r e a t m e n t were killed a p p r o x i m a t e l y 1, 2, 4 , 8, and 2 4 hr after being injected with t h e radioisotope. Blood samples in triplicate, t o t a l excretion, and tissue samples including skin, muscle, heart, liver, intestine, and b o n e in triplicate were collected from each bird and c o u n t e d in an a u t o m a t i c g a m m a c o u n t e r (Baird A t o m i c Iso/Matic Model 707) with an efficiency of 30% d e t e r m i n e d with a g a m m a reference source of
652
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ABSTRACT Adult male chickens, which were maintained on a low dietary potassium intake for 11 weeks showed no gross abnormalities, but had significantly reduced feed intake and losses of body weight. Adult male chickens had a physiological capacity to increase the biological half life of their body potassium from 18 to 134 days when the dietary potassium was reduced from .32 to .02%. However, the deficient birds were unable to balance their intake with the excretion because of the obligatory loss of potassium. The relative specific activity of different tissues in adult male chickens determined at different time intervals after the intravenous injection of potassium-42 indicated that the plasma pool potassium had the highest turnover rate of potassium in the body. In decreasing order, it was followed by the skin, heart, liver, intestine, bone, and muscle. The daily balance of potassium in adult male chickens maintained under optimum and sub-optimum dietary potassium intake gave an estimated minimum requirement for this element of .06% of the diet.
POTASSIUM FOR ADULT MALE CHICKENS TABLE 1. Potassium deficient diet for adult male chickens Ingredient
(g/kg)
Corn starch Glucose monohydrate a Cellulose 0 Isolated soybean protein c Soybean oil CaHP04-2H20 CaC0 3 Mineral mixture*! Vitamin mixture e DL-methionine
400 230 129.4 160 40 14 2.6 10 10 4
%•
Cesium 137. Total excreta after injection with potassium-42 were collected individually, brought to an exact volume with 1% nitric acid, homogenized in an electric mixer, and sampled in triplicate for counting. Subsequently, total excreta samples were collected, dried, ashed in a muffle furnace at 600 C, and analyzed to determine total potassium content. Counts were recorded with the time of counting and the hour of the day for each individual sample, and later corrected for decay (half life, 744 min). Total counts were finally expressed as counts/ min/g of sample. Analysis of potassium content allowed the calculation of specific activity in counts/min/mg potassium.
RESULTS Deficient roosters maintained their body weight unaffected by the deficiency of potassium until the 4th week of the experimental period (Table 2). From the 5th to the 11th experimental week, body weight was significantly reduced in comparison to the control roosters.
The control birds showed a slight gain in body weight (4.65%) during the entire experiment. Thus, the final body weight difference between deficient and control birds was due to the decrease in body weight in the deficient, and, to a lesser degree, a small increase in the body weight of the control birds. Average daily feed intake for weekly periods for roosters fed the potassium-deficient diet was unaffected for the first four experimental weeks (Table 2). Subsequently, there was a significant reduction in daily feed intake in the deficient birds during the 5th, 6th, 10th, and 11th weeks compared to the control birds. Overall there was a significant decrease (p=<.005) in daily feed intake of the deficient males compared to the potassium-supplemented birds. The abrupt reduction in feed intake in both groups observed during the first experimental week could be due to the change in type of feed. The most striking difference in potassium excretion between supplemented and deficient adult chicken males, was the reduction in potassium loss through the feces and urine in the deficient chickens (Table 3). The potassium excretion was relatively constant in each of the groups for the three experimental periods shown, but the excretion from the deficient birds was approximately one tenth that of the potassium-supplemented chickens. The reduced calcium excretion in the last balance trial was due to the lowering of the calcium level in the diets. The potassium content of the blood plasma of potassium-deficient roosters was significantly lower at the end of the experiment (Table 4). The skin of the deficient birds had less dry matter, but there was no difference in potassium content between the potassium-deficient and supplemented groups. Heart and muscle weights from deficient chickens were slightly less than the controls but there was no difference in potassium content between the two groups. The intestine and liver from deficient chickens contained more potassium than the controls. There were no differences in the composition of the bone between the two groups. The excretion of potassium-42 (Table 5) was far greater in the potassium-supplemented chickens than in those deficient in potassium. From these data by using the chi square method of regression analysis, the biological half life of potassium was found to be 18 days for the supplemented birds and 134 for those
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Cerelose. Solka floe from Brown Co., Berlin, NH. c Ralston Purina RP-100. d Supplied in g/kg diet: NaCl, 5.0; MgSO„, 2.5; MnSO„-H20, .2; FeS0 4 -7H 2 0, .4; CuS0 4 -5H 2 0, .05; Co acetate.4H 2 0, .01; Nal, .004; A1 2 (S0 4 ) 3 18H 2 0, .1; Na 2 Mo0 4 -2H 2 0, .009; ZnO, .1; Na selenite, .0007; and NaF, .009. Supplied per kilogram diet: vitamin A 2,275 IU vitamin D3, 325 ICU; vitamin E, 88 IU; menadione, 3 mg; thiamine'HCl, 10 mg; riboflavin, 10 mg; Ca pantothenate, 30 mg; niacin, 100 mg; pyridoxine-HCl, 10 mg; D-biotin, .2 mg; folic acid, 5 mg; vitamin B, 2 , 30 meg; butylated hydroxytoluene, .5 mg; and inositol, 1 b
653
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TABLE 3. Analysis of total excreta collected in 24 hr in adult chicken males at different times during the experimental period
2 weeks
8 weeks
4 77 + 4a 42 ± 3 17.0 ± .62 2.22 ± .09 41.06 ± 2.80 1 3 . 0 7 + .12 6.81 ± .41 7.12 + .65 3.54 ± .11 19.08 + .36
4 89 ±8 58 ±5 1 8 . 2 4 + 1.06 2 . 0 3 + .13 31.79 ± 1.33 11.17 ± .53 7.14 ± 1.05 6.28 ± .84 2.52 ± .10 34.69 ± 2.66
4 71 45 14.69 1.01 34.11 6.86 6.04 5.85 2.72 2.13
± 7 ± 7 ± .96 ± .10 ± 3.82 ± .43 + .43 ± .78 + .31 ± .13
5 67 +13 38 ±8 16.5 + 2.34 1.83 ± .40 4 7 . 9 8 ± 8.5 10.79 ± .84 6.42 ± .87 .65 ± .10 3 . 4 8 + .46 17.96 ± 2.60
5 73 36 13.87 1.18 39.79 8.52 4.09 .68 2.00 20.33
5 69 50 14.55 .60 30.87 4.09 4.01 .62 2.58 2.71
+ 5 ± 6 + .90 ± .05 ± 3.31 ± .20 ± .38 ± .04 + .21 ± .26
±5 +5 ± 1.31 ± .11 ± 2.60 ± .10 ± .68 ± .10 ± .13 ± 2.51
aMean ± SEM.
deficient in potassium. Turnover rates were 3.86% per day for the supplemented and .5% per day for the deficient birds and the turnover time was 25.9 days compared with 193.7 days for those deficient. The specific activity of the plasma at 1 hr was 1/140 of the calculated value after the intravenous injection. The ratio of specific activities of the tissue and organs compared with the specific activity of the plasma are shown in Table 6. Muscle was the only tissue which did not achieve 100% interchange even after 24 hr. The results obtained from the potassium-deficient roosters were similar in general, however, the liver, intestine, and bone samples of the deficient roosters appeared to have lower and more stable relative specific activities than the supplemented controls. DISCUSSION The response of adult male chickens to a dietary potassium deficiency was different for the different organs and tissue structures. Thus, while the pectoral muscle, intestine, liver, and
bone maintained a normal hydration state, skin and heart suffered hyperhydration. Without taking into account this water balance modification, the ash content of the skin, muscle, intestine, heart, and bone were maintained at normal levels, while in the liver there was a slight but significant increase in ash content. This increase in ash content of the liver can be explained both by the slight increase in dry matter and a significant increase in potassium content. Neither muscle, or intestine showed any significant alteration in dry matter or ash content with the potassium-deficient diet, but muscle significantly decreased and intestine significantly increased in potassium content. This strongly indicates that electrolyte compensation was complete. The heart hyperhydration in response to a dietary potassium deficiency appears as the only adjustment made to maintain the total ash and potassium concentration at normal levels. Exactly the same situation held for the skin. The overall picture observed in adult male chickens deficient in potassium suggested that survival was achieved fundamentally
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Potassium supplemented roosters Number of individual feces collected Feed intake/day during collections, g Total excretion fresh weight, g Total dry matter excreted, g Total ash excreted, g Dry matter, % Ash in dry matter, % Total sodium excreted, mEq/24 hr Total potassium excreted, mEq/24 hr Total magnesium excreted, mEq/24 hr Total calcium excreted, mEq/24 hr Potassium deficient roosters Number of individual feces collected Daily feed intake day of collection, g Total excretion fresh weight, g Total dry matter excreted, g Total ash excreted, g Dry matter, % Ash in dry matter, % Total sodium excreted, mEq/24 hr Total potassium excreted, mEq/24 hr Total magnesium excreted, mEq/24 hr Total calcium excreted, mEq/24 hr
Experimental period 5 weeks
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TABLE 4. Dry matter, ash, and potassium content of some tissues and organs of adult male chickens fed potassium supplemented and deficient diets K-supplemented mean ± SEM a Blood plasma: mEq K/liter
4.51 + .48a
K-deficient mean ± SEM
2.71 ±
.20b
t- test significance
P<.025
48.29 .43 .18 .47
± ± ± ±
1.94 .03 .03 .08
42.02 .43 .18 .47
± 1.51 ± .02 ± .03 ± .08
P<.05 NS NS NS
Heart: Heart weight, g Dry matter, % Ash, % mg K/g sample Potassium, mEq/100 g
12.77 30.41 .98 1.74 4.46
+ + ± ± ±
.83 1.00 .05 .13 .33
10.53 27.34 .97 1.82 4.66
± .74 ± 1.03 ± .04 ± .11 ± .29
P<.05 P<.05 NS NS NS
Muscle: Dry matter, % Ash, % mg K/g sample Potassium, mEq/100 g
27.11 1.17 2.64 6.74
± ± ± ±
.26 .02 .09 .24
27.34 2.23 2.33 5.96
± + + ±
.25 .04 .09 .23
NS NS P<.025 P<.025
Intestine: Dry matter, % Ash, % mg K/g sample Potassium, mEq/100 g
26.70+ 1.26 ± 2.09 ± 5.35 ±
1.18 .02 .06 .16
24.61 1.29 2.37 6.07
± ± ± ±
.37 .01 .08 .20
NS NS P<.025 P<.025
Liver: Dry matter, % Ash, % mg K/g sample Potassium, mEq/100 g
26.39 1.16 1.39 3.56
± ± ± ±
.50 .03 .07 .19
26.72 1.22 1.64 4.19
± ± ± ±
.37 .02 .08 .21
NS P<.05 P<.001 P<.001
Bone: Tibia weight, g Dry matter, % Ash, % Potassium, mEq/100 g
18.42 78.55 34.78 1.11
+ ± ± ±
1.14 .75 1.03 .10
18.22 75.44 34.07 .92
± 1.17 ± 1.45 ± 1.49 ± .11
NS NS NS NS
Ten birds for each treatment were sampled in triplicate for each tissue.
at muscle expense. The total muscle mass was significantly reduced which was reflected in body weight values. Potassium concentration in the muscle was also significantly reduced. Cardiac muscle weight reduction was demonstrated; a significant reduction in the total potassium excretion was, of course, another contributing mechanism in the survival capacity of adult male chickens under potassium deficiency, but it was limited by the obligatory potassium component of the urinary excretion. Finally, the dramatic reduction in the turnover rate of potassium or the immense increase in the biological half life of potassium represents the summation of many adjustments performed at the cellular level for conserving potassium
under a dietary deficiency. Skin and heart tissues showed the highest relative specific activity approximately 1 hr after the injection of potassium-42. Relative specific activities of the intestine, liver, and bone decreased in order. In all of these tissues, the relative specific activity was higher than 1. This fact, however, can hardly represent more than 100% potassium exchange. Neither can the RSA value of greater than 1 be interpreted as an accumulation of the injected labeled potassium in these tissues since this would invalidate the principle that the radioactive element has the same behavior within the organism as the natural one. It was observed that the maximum specific activity of the plasma at about 1 hr
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Skin Dry matter, % Ash, % mg K/g sample Potassium, mEq/100 g
POTASSIUM FOR ADULT MALE CHICKENS
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TABLE 5. Excretion of potassium 42 at different times after being injected into potassium deficient and supplemented adult male chickens3Potassium deficient
Potassium supplemented Time after injection (min)
K excreted Total (cpm X 10 3 )
Time after injection (min)
Total " 2 K excreted (cpm X 10 3 )
54 87 157 176 295 301 496 497 1424 1425
799.2 499.6 1348.7 2547.5 2407.6 6343.7 3716.3 5264.5 4225.8 4625.4
65 88 157 185 300 302 481 496 1425 1426
30.0 0 189.8 109.8 99.9 289.7 179.8 249.8 259.7 559.4
18 days 3.86%/day 25.9 days
Biological half time of K Turnover rate of K Turnover rate of K
after the isotope injection was about 1/140th of the original value. This shows that the decay was very rapid representing a very fast turnover rate for the potassium in the plasma. The relative specific activity represents a turnover rate of potassium in the respective tissue relative to the turnover rate in the plasma; thus it can be concluded that the plasma pool potassium has the highest turnover rate in the body. The skin has the next highest turnover rate because it
134 days .5%/day 193 days.
reaches the highest relative specific activity about 1 hr after injecting the potassium-42 and its decay was faster than any other tissue. Skin was followed by the heart, liver, intestine, and bone in decreasing order of turnover rates. Uptake of potassium-42 by the muscle was relatively slow and its turnover rate was also very slow. Bone, intestine, and liver were the tissues most responsible for the great reduction in the turnover rate of body potassium observed in
TABLE 6. Relative specific activities for various tissues at different times after injection with 4 2 K Exp. time* minute
SA b plasma
Relative specific activity 0 Skin
Heart
Liver
Intestine
Bone
Muscle
55,710 44,587 40,759 67,770 45,921
7.64 3.54 5.34 2.52 3.64
3.46 2.38 1.45 1.14 1.14
2.85 1.31 1.27 .99 .91
2.91 1.91 1.92 1.75 1.42
1.98 .79 .95 .84 1.40
.57 .42 .43 .45 .64
K-deficient roosters 77 60,164 171 57,259 301 44,796 489 60,860 1426 59,257
7.32 4.36 6.99 3.97 2.09
2.86 1.52 1.89 .94 1.89
1.79 1.19 1.59 .91 1.10
1.75 1.87 2.28 1.52 1.39
1.13 1.46 1.97 2.09 1.32
.45 .33 .88 .36 .56
K supplemented roosters: 76 166 298 496 1425
Time period between " 2 K injection and the death of the bird. Average of two roosters for each time. Specific activity determined (CPM/mg K) in the plasma. Ratio of the SA in the plasma and the SA in the tissue at different time intervals.
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egg contains approximately 100 mg, equivalent to .04% dietary potassium at 60% egg production. REFERENCES Ben-Dor, B., 1941. Requirement of potassium by the chick. Proc. Soc. Exp. Biol. Med. 4 6 : 3 4 1 - 3 4 3 . Fenn, W. O., T. R. Noonan, L. J. Mullins, and L. Haege, 1941/42. The exchange of radioactive K with body K. Amer. J. Physiol. 135:149-163. Gillis, M. B., 1948. Potassium requirement of the chick. J. Nutrition 36:351-357. Hevesy, G., 1948. Radioactive indicators. Interscience Publishers, Inc. New York. Leach, R. M., 1974. Studies on the potassium requirement of the laying hen. J. Nutrition 104:684-686. Leach, R. M., Jr., R. Dam, T. R. Zeigler, and L. C. Norris, 1959. The effect of protein and energy on the potassium requirement of the chick. J. Nutrition 68:89-100. Noonan, T. R., W. O. Fenn, and L. Haege, 1941. The distribution of injected radioactive K in rats. Amer. J.Physiol. 132:474-488. Norris, L. C , F. H. Kratzer, H. J. Lin.A. B. Hellewell, and J. R. Beljan, 1972. Effect of quality of dietary calcium on maintenance of bone integrity in mature White Leghorn male chickens. J. Nutriton 102:1085-1092. Rinehart, K. E., J. C. Rogler, and W. R. Featherston, 1968. Influence of dietary potassium on chick growth, food composition, and blood and tissue composition. Poultry Sci. 47:320—325. Sunde, M. L., J. R. Couch, L. S. Jensen, B. E. March, E. C. Naber, L. M. Potter, and P. E. Waibel, 1977. Nutrient requirement of poultry. Nat. Acad. Sci., Washington, DC.
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the potassium-deficient group of roosters. The turnover rate of the skin, however, appeared to be unaffected. These results are in good agreement with those reported by Noonan et al. (1941) and Fenn et al. (1941/42), but are not in agreement with the interpretation given to them by Hevesy (1948). If the negative potassium balance obtained with the potassium-deficient roosters represents the minimum daily excretion of potassium under this dietary regimen, then this truly represents an obligatory component of the daily requirement. On the other hand, the positive potassium balance obtained with the potassium-supplemented roosters represents the maximal potassium retention for the optimal metabolic activity of birds that are gaining some body weight; this also represents another obligatory component of the daily requirement for potassium. Therefore, the addition of these two components may well be a good estimate of the minimum requirements for potassium for adult male chickens. This value is 45 mg of potassium per day, which represents .06% of the diet assuming feed consumption similar to that of the potassium-supplemented group of birds. This is considerably lower than the potassium requirement for the growing chicken of .2% but is in good agreement with the need for the laying hen of .1% reported by Leach (1974), particularly if it is assumed an