Influence of dietary calcium and phosphorus on metabolism and production in laying hens

Abstract

1. The effects of different dietary concentrations of calcium (24 to 56-9 g/kg) and phosphorus (4-5 to 14-2 g/kg) on production and some aspects of metabolism were studied in laying hens. 2. Treatments did not affect egg numbers, food consumption, conversion efficiency of food to egg, bodyweight gain or mortality. 3. Increasing dietary calcium (Ca) significantly increased plasma Ca and inorganic phosphorus (P), breaking strength at the radius and egg specific gravity and significantly decreased plasma alkaline phosphatase and egg weight. 4. Increasing dietary phosphorus increased plasma P and decreased egg specific gravity significantly. 5. Plasma Ca, P and alkaline phosphatase and radius breaking strength were suitable indices of the Ca status of the hens.

The egg‐laying response of the domestic hen to variation in dietary calcium

“…They are consistent with most previously published work (Hurwitz and Griminger, 1960;Maclntyre et al, 1963;Gilbert, 1969;Douglas etal, 1972;McCready et al, 1973;Reichmann and Connor, 1977;Roland et al, 1978;Balch, 1979;Husseini, 1979) but are considerably more extensive than those previously available. Also, because a systematic study on a uniform population of birds was carried out using a wide range of diets, it is possible to extrapolate from the results to obtain an estimate of the effect on egg production of diets containing just less than the accepted optimum of about 35 g calcium/kg; this has not been possible previously mainly because many of the reports are contradictory (compare the references given above with those of Petersen et al, 1960;Helbacka, 1961;Combs, 1962;Davidson and Boyne, 1970) and also because the reports are not always comparable since often different dietary calcium concentrations and different birds were used by the different authors.…”

Effects of Calcium and Phosphorus Levels on Egg Weight and Egg Shell Quality in Laying Hens

“…5418 College of Agriculture Research Center, Washington State University, Project 0296. deposition or quality at calcium levels in a range of 2.75 to 4.0%, the lower end of the range for hens laying at a rate of 60 to 70% and the higher end of the range for hens laying 70 to 80% (Bragg et al, 1971;Scott et al, 1971;Roland et al, 1974;Miller and Sunde, 1975;Summers et al, 1976;Holcombe et al, 1977, Kuhl et al, 1977Holder and Huntley, 1978). Although most reports do not conclude that dietary calcium level affects egg weight, Reichmann and Connor (1977) reported significantly lower egg weight from hens fed 4.3 or 5.7% calcium compared to those fed 3.2 or 2.4%.…”

Dietary Phosphorus Requirements of Laying Hens Kept in Floor Pens and Fed Diets Containing Canola Meal

“…Since the range in calculated total P levels in the experimental diets used was relativelY narrow (0.4-0.5Vo) it was unlikely that any difference in blood plasma inorganic P would be observed. Reichmann and Connor (1977) similarly found no difference in inorganic P levels in plasma when the diets contained from 0.45 to 0.80Vo P, but higher levels than this in the diet produced marked increases in plasma inorganic P levels.…”