Effect Of Dietary Phosphorus Levels Research Articles

The Effects of Dietary Phosphorus, Vitamin D3, and 25-Hydroxy Vitamin D3 Levels on Feed Intake, Productive Performance, and Egg and Shell Quality in Two Strains of Force-Molted White Leghorns

A total of 576 force-molted hens were used to investigate the effect of dietary phosphorus level, and the source and level of vitamin D3 on egg production and shell quality. The experiment was a 2 × 2 × 2 × 3 factorial design with two strains of hens, two levels of available phosphorus (.34 and .60%), and two sources of D3 (25-hydroxy vitamin D3 and vitamin D3) at three levels (8, 16, 24 μg/kg); the diets were provided ad libitum for 84 days (from 646 to 730 days of age). Egg and shell quality measurements were taken on eggs laid over a 4-day period when the hens were 727 days of age. Dietary phosphorus level, and D3 source and level had no significant (P>.05) effect on 730-day body weight, feed intake and efficiency, egg production and yield, shell weight, percent shell, shell weight per unit surface area, Haugh units, blood spots, egg specific gravity, nondestructive deformation, compression fracture force, and shell thickness. There were significant differences among strains for the aforementioned variables except feed intake, egg weight, Haugh units, and blood spot incidence. Few interactions were found between the main effects. Results indicate that no improvement in shell quality of eggs from force-molted hens was obtained by decreasing the level of phosphorus or substituting 25-hydroxy vitamin D3 for vitamin D3 in the diet.

A principal source of deposited lipid in phosphorus deficient red sea bream.

To clarify a principal source of deposited lipid in phosphorus deficient red sea bream, Chrysophrys major, the effect of dietary phosphorus level on the absorption of dietary lipid and the effects of dietary carbohydrate and lipid levels on lipid content of the carcass were examined. The absorption of dietary lipid showed a similarly high value in all groups without regard to dietary phosphorus level. Phosphrous deficient fish on diets with and without carbohydrates, stored lipid abundantly, but those on diets lacking lipid did not. Furthermore, fatty acid composition of deposited lipid in the adipose tissue was similar to that of dietary lipid. From these findings, it was presumed that dietary lipid was not well utilized as energy source and gradually accumulated in phosphrous deficient fish.

Effect of dietary phosphorus level on chemical composition of red sea bream.

Red sea bream, Chrysophrys major, fed diets containing different levels of phosphorus for 76 days were analyzed to determine the chemical composition of the entire body, dorsal muscle, liver, and vertebrae. It was found that the decrease of the dietary phosphorus level resulted in the increase in the lipid contents of the muscle, liver, and vertebrae and in the decrease in the glycogen content of the liver and in the crude ash, calcium, and phosphorus content of the vertebrae. Little difference, however, was noted in the Ca/P ratio in the vertebrae among the various experimental groups.

The Effect of Dietary Phosphorus Level and Strain of Bird on the Apparent Metabolizable Energy Content of a Laying Hen Diet

An experiment was made in which laying hen diets containing four different levels of dicalcium phosphate were each fed to two replicate groups of 10 strains of S.C.W.L. hens. The apparent metabolizable energy (A.M.E.) values of the diets were measured. There was a small but significant (P < 0.01) linear increase in the dietary A.M.E. value associated with decreasing levels of phosphorus. The A.M.E. values did not differ between strains of birds (P > 0.05) and there was no phosphorus level × strain interaction (P > 0.05).