The Response of Serum Inorganic Phosphorus Level in Laying Hens Fed Low Levels of Dietary Phosphorus1 J. H. CHOI, R. D. MILES, and R. H. HARMS Department of Poultry Science, Florida Agricultural Experiment Gainesville, Florida 32611
Station,
(Received for publication May 24, 1978)
1979 Poultry Sci 58:416-418 INTRODUCTION
EXPERIMENTAL PROCEDURE
Early r e p o r t s (Feinberg et al., 1 9 3 7 ; Peterson and Parrish, 1 9 3 9 ; Paul and Snetsinger, 1969) have indicated t h a t b l o o d plasma inorganic p h o s p h o r u s of t h e laying hen fluctuates with t h e daily cycle of egg p r o d u c t i o n . Miller et al. ( 1 9 7 7 ) investigated t h e cyclic p a t t e r n of serum p h o s p h o r u s of laying hens during a 24-hr period. T h e y f o u n d t h a t b l o o d p h o s p h o r u s followed t h e cycle for egg shell f o r m a t i o n and bone redeposition. These results imply t h a t it is i m p o r t a n t t o consider t h e p r o d u c t i o n status of t h e hen in e x p e r i m e n t s where serum p h o s p h o rus is measured.
Three e x p e r i m e n t s were c o n d u c t e d using Babcock B-300 laying hens. All hens were fed a diet containing . 7 5 % p h o s p h o r u s and 3.50% calcium prior to t h e initiation of each e x p e r i m e n t . In all e x p e r i m e n t s , hens were housed in individual wire cages and were fed t h e experimental diets ad libitum. E x p e r i m e n t a l diets were mixed from a corn-soybean meal basal diet (Choi et al., 1979) b y substituting t h e necessary a m o u n t s of limestone, dicalcium p h o s p h a t e , and white builder's sand in place of t h e variable portion t o obtain t h e desired levels of calcium and p h o s p h o r u s . T h e basal diet contained .30% p h o s p h o r u s , all from plant sources. T h e diet containing .22% p h o s p h o r u s was obtained b y replacing t h e yellow corn in t h e basal diet b y an equal a m o u n t of d e g e r m i n a t e d corn meal. Each e x p e r i m e n t a l diet was formulated t o contain 3.50% calcium.
In a m o r e recent s t u d y , Choi et al. ( 1 9 7 9 ) indicated t h a t t h e serum p h o s p h o r u s level was lower w h e n hens were fed a p h o s p h o r u s deficient diet. However, t h e r e is a lack of d a t a concerning t h e relationship b e t w e e n dietary p h o s p h o r u s and serum p h o s p h o r u s levels of h e n s . T h e present s t u d y was c o n d u c t e d t o determine t h e effects of feeding lower levels of dietary p h o s p h o r u s on t h e serum p h o s p h o r u s of laying hens.
'Florida Agricultural Experiment Station, Journal Series No. 1195.
Blood samples were collected b y heart p u n c ture immediately after oviposition from 8 t o 10 hens per t r e a t m e n t t h a t had laid for t w o consecutive days in each e x p e r i m e n t . No birds were bled twice in this s t u d y . Serum inorganic phosp h o r u s level was d e t e r m i n e d by t h e m e t h o d of Harris and P o p a t ( 1 9 5 4 ) after deproteinization of t h e serum.
416
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ABSTRACT Three experiments were conducted to determine the effects of feeding low levels of dietary phosphorus on the serum inorganic phosphorus level of laying hens. A phosphorus deficient diet containing .30% total phosphorus, all of plant origin, was fed to hens for 3 days in Experiment 1 and 4 weeks in Experiment 2. In Experiment 3, seven different levels of dietary phosphorus were fed. Blood serum inorganic phosphorus level was determined at different durations of feeding the experimental diets. All the blood samples were collected immediately following oviposition from the hens that had laid both on the day before and the day of bleeding in each experiment. The serum phosphorus level of hens previously fed .75% phosphorus was 4.12 mg/100 ml in Experiment 1 and 4.72 mg/100 ml when fed .75% phosphorus in Experiment 3. Serum phosphorus level of hens fed the diet containing .30% phosphorus decreased to between 2 and 3 mg/100 ml within 24 hr and remained at this level for 4 weeks. There were no significant differences in serum phosphorus levels of hens fed levels of dietary phosphorus between .375% and 1.40%. Decreasing dietary phosphorus from .30% to .22% further decreased the serum phosphorus level. It is concluded that the hen is capable of maintaining a normal blood phosphorus level over a wide range of dietary phosphorus, but decreases her serum phosphorus level immediately when fed suboptimal levels of phosphorus.
DIETARY AND SERUM PHOSPHORUS
RESULTS AND DISCUSSION The serum inorganic phosphorus level immediately after oviposition of hens previously fed the diet containing .75% phosphrous was 4.12 mg/100 ml in Experiment 1 (Fig. 1) and 4.72 mg/100 ml when fed .75% phosphorus in Experiment 3 (Table 1). Feeding the diet containing .30% phosphorus resulted in a significant decrease in the serum phosphorus level of hens within one day (P
Station,
(Received for publication May 24, 1978)
1979 Poultry Sci 58:416-418 INTRODUCTION
EXPERIMENTAL PROCEDURE
Early r e p o r t s (Feinberg et al., 1 9 3 7 ; Peterson and Parrish, 1 9 3 9 ; Paul and Snetsinger, 1969) have indicated t h a t b l o o d plasma inorganic p h o s p h o r u s of t h e laying hen fluctuates with t h e daily cycle of egg p r o d u c t i o n . Miller et al. ( 1 9 7 7 ) investigated t h e cyclic p a t t e r n of serum p h o s p h o r u s of laying hens during a 24-hr period. T h e y f o u n d t h a t b l o o d p h o s p h o r u s followed t h e cycle for egg shell f o r m a t i o n and bone redeposition. These results imply t h a t it is i m p o r t a n t t o consider t h e p r o d u c t i o n status of t h e hen in e x p e r i m e n t s where serum p h o s p h o rus is measured.
Three e x p e r i m e n t s were c o n d u c t e d using Babcock B-300 laying hens. All hens were fed a diet containing . 7 5 % p h o s p h o r u s and 3.50% calcium prior to t h e initiation of each e x p e r i m e n t . In all e x p e r i m e n t s , hens were housed in individual wire cages and were fed t h e experimental diets ad libitum. E x p e r i m e n t a l diets were mixed from a corn-soybean meal basal diet (Choi et al., 1979) b y substituting t h e necessary a m o u n t s of limestone, dicalcium p h o s p h a t e , and white builder's sand in place of t h e variable portion t o obtain t h e desired levels of calcium and p h o s p h o r u s . T h e basal diet contained .30% p h o s p h o r u s , all from plant sources. T h e diet containing .22% p h o s p h o r u s was obtained b y replacing t h e yellow corn in t h e basal diet b y an equal a m o u n t of d e g e r m i n a t e d corn meal. Each e x p e r i m e n t a l diet was formulated t o contain 3.50% calcium.
In a m o r e recent s t u d y , Choi et al. ( 1 9 7 9 ) indicated t h a t t h e serum p h o s p h o r u s level was lower w h e n hens were fed a p h o s p h o r u s deficient diet. However, t h e r e is a lack of d a t a concerning t h e relationship b e t w e e n dietary p h o s p h o r u s and serum p h o s p h o r u s levels of h e n s . T h e present s t u d y was c o n d u c t e d t o determine t h e effects of feeding lower levels of dietary p h o s p h o r u s on t h e serum p h o s p h o r u s of laying hens.
'Florida Agricultural Experiment Station, Journal Series No. 1195.
Blood samples were collected b y heart p u n c ture immediately after oviposition from 8 t o 10 hens per t r e a t m e n t t h a t had laid for t w o consecutive days in each e x p e r i m e n t . No birds were bled twice in this s t u d y . Serum inorganic phosp h o r u s level was d e t e r m i n e d by t h e m e t h o d of Harris and P o p a t ( 1 9 5 4 ) after deproteinization of t h e serum.
416
Downloaded from http://ps.oxfordjournals.org/ by guest on April 9, 2015
ABSTRACT Three experiments were conducted to determine the effects of feeding low levels of dietary phosphorus on the serum inorganic phosphorus level of laying hens. A phosphorus deficient diet containing .30% total phosphorus, all of plant origin, was fed to hens for 3 days in Experiment 1 and 4 weeks in Experiment 2. In Experiment 3, seven different levels of dietary phosphorus were fed. Blood serum inorganic phosphorus level was determined at different durations of feeding the experimental diets. All the blood samples were collected immediately following oviposition from the hens that had laid both on the day before and the day of bleeding in each experiment. The serum phosphorus level of hens previously fed .75% phosphorus was 4.12 mg/100 ml in Experiment 1 and 4.72 mg/100 ml when fed .75% phosphorus in Experiment 3. Serum phosphorus level of hens fed the diet containing .30% phosphorus decreased to between 2 and 3 mg/100 ml within 24 hr and remained at this level for 4 weeks. There were no significant differences in serum phosphorus levels of hens fed levels of dietary phosphorus between .375% and 1.40%. Decreasing dietary phosphorus from .30% to .22% further decreased the serum phosphorus level. It is concluded that the hen is capable of maintaining a normal blood phosphorus level over a wide range of dietary phosphorus, but decreases her serum phosphorus level immediately when fed suboptimal levels of phosphorus.
DIETARY AND SERUM PHOSPHORUS
RESULTS AND DISCUSSION The serum inorganic phosphorus level immediately after oviposition of hens previously fed the diet containing .75% phosphrous was 4.12 mg/100 ml in Experiment 1 (Fig. 1) and 4.72 mg/100 ml when fed .75% phosphorus in Experiment 3 (Table 1). Feeding the diet containing .30% phosphorus resulted in a significant decrease in the serum phosphorus level of hens within one day (P
