Immunoquantitation of rat erythrocyte superoxide dismutase: its use in copper deficiency.

Two immunoassays have been developed for the determination of rat erythrocyte dismutase (Cu,Zn-SOD). An enzyme-linked immunosorbent assay (ELISA) was very sensitive down to 4 ng/ml with a coefficient of variation (CV) of 18% while the single radial immunodiffusion assay (SRID) permitted an adequate detection level (5 micrograms/ml) with far better accuracy (CV = 4.2%). The latter was thus selected for the determination of Cu,Zn-SOD in the red blood cells of normal and copper-depleted rats. The average value of Cu,Zn-SOD in normal adult rat erythrocytes was 1142 +/- 120 ng/mg hemoglobin. When compared to activity measurements, good correlation was obtained between enzyme content and enzyme activity (r = 0.803, P less than .001). In an experimental copper deficiency followed by supplementation, good correlation was observed in the course of depletion (r = 0.848, P less than .001) and repletion (r = 0.896, P less than .001). During depletion, the loss of enzyme activity was mainly related to a loss of enzyme. However, enzymatically inactive protein was formed which would be activated when copper was added. These results indicate the importance of a combined use of Cu,Zn-SOD immunoquantitation and activity measurements to enable a better understanding of changes occurring with respect to enzyme activity.

The influence of sulfur supplementation (methionine and sulfate) on the zinc availability of a poor diet in sheep.

A poor hay, with a low proteic level, decreases the zinc availability in lambs. Increasing the sulfur level with methionine and sulfate, of such a diet, enhances zinc absorption. However, sulfur is not the only factor limiting zinc availability in a hypoproteic diet.

A zinc-deficient diet for ruminants: diagnosis and treatment of deficiency.

A zinc deficient diet which is not semi-synthetic was tried on 20 male Limousin X Romanoff three and a half month-old sheep weighing 36 kg on average. This diet was composed of strawy hay sprayed with caramel containing urea and minerals. Compared to hay alone this diet is more appetizing to lambs and more equilibrated as to energy level and soluble nitrogen utilization. The deficiency appeared within a week in zinc plasma and progressed clinically within 100 days. The plasmic free zinc and alkaline phosphatase were not better criteria for the deficiency diagnosis than total plasmic zinc. Supplementing the diet to 50 or even 100 mg Zn/kg DM was insufficient to suppress the deficiency. Zinc injection, by contrast, restored zincemia to normal in ten days. Zinc deficiency treatment by oral route should be reconsidered.