Serum phosphatase in the domestic fowl

Abstract

1. Some observations on the serum phosphatase of the domestic fowl are described. Laying hens, held to be normal birds, had higher and more variable serum phosphatase than cocks. No great difference in serum phosphatase could be found between laying hens and hens in a period of suspended egg production. Pullets from another source and which had never laid gave values comparable with the value for cocks. 2. The serum phosphatase of chicks shows a rapid increase to a maximum at about 10–12 days after hatching, followed by an equally sharp fall to a lower level at 3 weeks. Thereafter, the values for male birds fall regularly until maturity. The values for female birds correspond closely with the values for male birds until the onset of laying, when they increase again, but to a varying degree in different individuals. 3. An attempt to reduce the range of variation of serum phosphatase in laying birds by administration of 1 ml. per bird per diem radiostol B.D.H. (3000 international units vitamin D per ml.) was not successful. 4. Serum phosphatase showed a much greater increase during laying in pullets receiving a low calcium ration (0·37 per cent. CaO) than in pullets receiving the same ration supplemented with calcium carbonate (3·10 per cent. CaO). 5. Serum phosphatase is greatly increased in chicks suffering from rickets.