Enzyme Studies in Thiamine-deficient Pigeons

Abstract

White Carneau pigeons are significantly more susceptible to thiamine-deficiency than are pigeons of the Show Racer breed. When the two breeds were force-fed a thiamine-deficient diet, the levels of thiamine in the brains and livers of both breeds decreased, but to about the same extent. After feeding the deficient diet for approximately 14 days, the White Carneau pigeons exhibited deficiency signs, whereas those of the Show Racer breed did not. Nonetheless, neither the level of pyruvate oxidase (as measured by increases in blood pyruvate), nor of blood transketolase differs significantly in the two breeds. Likewise, the activity of α-ketoglutarate oxidase decreases to the same extent in the brains and livers of both breeds of pigeons. On the other hand, the activity of brain transketolase in either breed did not appear to change as the deficiency progresses. It is postulated that the appearance of the neurological signs of thiamine deficiency is related to factors other than the decreased activity of the enzyme systems studied here.