Availability to chicks of biotin from dried egg products.

Two feeding experiments were conducted with duplicate groups of five chicks each to study the availability of biotin in spray-dried egg products. In the first experiment chicks that were fed diets containing 43% dried whole egg (DWE) grew poorly and developed perosis and dermatitis. The signs were prevented and growth improved progressively with supplementation of 0.5 and 1.0 mg biotin/kg diet. In the second experiment dried egg yolk (DEY) and dried egg white (DEW) were compared with DWE at equivalent levels of egg components. Signs of biotin deficiency and reduced growth were slightly more severe with DEW than with DWE, although liver biotin content was slightly lower at 0 and 0.5 mg biotin/kg with DWE than with DEW. Growth with DEY and no added biotin was not different from that with DEY and 500 or 1000 mg biotin/kg diet, although liver biotin was lower than when supplemental biotin was added. Liver fat was approximately five times greater in the groups receiving DWE and DEY than in the groups receiving DEW. The results show that the biotin contained in egg yolk is inadequate to counteract the deficiency of biotin caused by the avidin in egg white so that unheated dried whole egg is deficient in this vitamin.