[Alpha amylase and dehydrogenase activity in suboptimal Ni intake]

Supplementary to studies on the activity of various enzymes during Ni deficiency, the present work was done to determine their response to suboptimal Ni supply. Live weight gain of rats was not affected by 60 versus 150 ppb Ni in the diet. The activity of alpha-amylase, however, was reduced by 43% in the case of 60 ppb dietary Ni and in relation to the change in this enzyme the activity of glucose-6-phosphate dehydrogenase by 56% and of the lactate dehydrogenase by 27%. These dehydrogenases responded with increased activities to the slight raise in Ni supply with the diet containing 150 ppb Ni as compared to the group given 60 ppb dietary Ni. Overall, it may be inferred that growth is not affected unless dietary Ni supply is below 50 ppb and that dietary Ni contents of 60 and 150 ppb must be regarded as suboptimal supply levels because of the diminished activity of various enzymes.