CHONDRODYSTROPHY IN THE CHICK EMBRYO PRODUCED BY A MINERAL DEFICIENCY IN THE DIET OF THE HEN

Abstract

THE report of Wilgus and coworkers1 on the preventive action of manganese, aluminum, zinc and iron on the occurrence of slipped tendon (perosis) in young growing chicks, together with our observations of a number of chicks hatched with slipped tendon, led us to study the effects on embryonic development and hatchability of feeding a slipped-tendon-producing ration to laying hens. Eggs from hens that had been fed such a ration for two months gave a hatchability of less than 10 per cent. Those embryos that were sufficiently developed before death for observation showed, without exception, very short legs and wings and parrot beak. The few chicks that hatched, although having short legs, did not have slipped tendon. Another group of hens fed the same ration plus 40 ppm each of manganese and zinc, as the respective sulfates, and 100 ppm of iron, as ferrous ammonium sulfate, produced eggs giving good hatchability and all normal chicks. Embryos that died showed normal development of appendages and mandibles. The eggs from the hens fed the slipped-tendon-producing ration contained much less manganese than those from the hens fed the same ration plus the mineral supplements indicated above. As a result of these analyses and of our studies2 on slipped tendon, we were inclined to attribute this condition to a manganese deficiency. This was proved to be correct by the injection of 0.03 mgs of manganese directly into the albumen of such eggs just prior to incubation, which resulted in normal development of the embryos and in an increase in hatchability. The metatarsi, tibiae and humeri of the chicks and 20-21-day embryos from the injected eggs were 52, 44 and 40 per cent. longer, respectively, than the same bones of those from the eggs which were not injected with manganese. The injection of .03 mgs of zinc into the albumen of the egg had no appreciable preventive effect on this disorder. These findings may offer some insight into the mechanism which produces slipped tendon in the growing chick. Further studies on this problem are in progress. This work will be published in detail elsewhere. MALCOLM LYONS W. M. INSKO, JR. KENTUCKY AGRICULTURAL EXPERIMENT STATION, LEXINGTON