LEVELS AND PARTITION OF THE FOWL'S SERUM PROTEINS IN RELATION TO AGE AND EGG PRODUCTION

Abstract

The level of total serum protein in the fowl has been followed from the 14th day of incubation to the 13th week of egg production. Serum proteins have been fractionated concurrently by zone electrophoresis in filter paper. Serum protein level in the 14-day embryo was 0.9 gm./100 ml. and the protein comprised a prealbumin fraction, albumin, α₂- and β-globnlins. Sera from chicks aged seven days no longer contained a prealbumin fraction but α₁-,α₃- and γ-globulin fractions had appeared by this stage and the protein level had reached 2.3 gm./100 ml. Total serum protein in females increased to a maximum of about 5.4 gm./100 ml. in the week before laying of the first egg. By that time two new protein fractions had appeared. These new fractions accounted for the greater part of the increase over the levels (4.0 gm./100 ml.) prevailing in the prepuberal stage. Serum protein level declined during the first three weeks of laying to average levels below 4.0 gm./100 ml.; and this decline appeared to affect albumin and α₁-globulin as well as the new fractions. As laying progressed, the total serum protein tended to regain a level around 4.0 gm./100 ml. The electrophoretic pattern also tended to return towards that prevailing in the week before laying. Some tentative correlations of the results of zone electrophoresis with published results for free electrophoresis of fowl serum proteins are presented.