The contribution of isozymes to alkaline phosphatase activity in chicken plasma

The contribution of different isozymes to plasma alkaline phosphatase (AP) activity was investigated in a White Plymouth Rock strain. No significant difference in AP acitivity between FF and FS genotypes was observed in both young chick and laying hen. As previously reported in young chickens, a significant difference in AP activity between F and S types was observed in laying hens. Of the total variance of AP activity 53%, 9% and 5% were explained by isozyme type, family and sex, respectively. The higher activity of the F band was responsible for the higher activity of the F type in the young chicken, while the activity of the B band of either type did not contribute to activity difference. The hypotheses are proposed so as to the activity difference.