Tetracyclines and Egg Shell Calcification

Abstract

Tetracyclines incorporate in bones and inhibit bone calcification in vivo and in vitro (Saxén, 1966). Oxytetracycline is deposited also in calcifying egg shells (Urist and Ibsen, 1963), which consist mainly of calcium carbonate as calcite crystals rather than apatite (Richardson, 1935). We aimed to study whether tetracycline or oxytetracycline interfers with egg shell calcification.Tetracycline or oxytetracycline (Pfizer, 100 mg./kg. of body weight) was injected intramusculary in regularly laying White Leghorn hens. A bright yellow fluorescence indicated the presence of the tetracyclines in the egg shells when the eggs were studied in UV-light (Fig. 1). Control eggs did not fluoresce.The concentration of oxytetracycline in the egg shell, albumen, and yolk was measured by UV-absorption spectrofluorometry (Hayes and DuBuy, 1964). Oxytetracycline was deposited mainly in the shell (0.182 ± 0.028 μg./gm., mean ± SD), and albumen (0.190 ± 0.030 μg./gm.) whereas the yolk contained only traces of oxytetracycline.The dry…