A Study of the Effect of Organic Zinc Supplementation on Glucose Metabolism and Insulin Resistance Indices in Early Lactation Ewes

The decreases in insulin sensitivity and extensive perinatal lipolysis are common causes of metabolic diseases related to energy metabolism in ewes.

The present study was designed to study the effect of organic zinc on glucose metabolism and insulin resistance indices in early lactating ewes.

18 Ghezel ewes were divided into three groups based on organic zinc supplementation, including CTR: (basal diet without Zinc), LZn: (basal diet supplemented with 30 mg Zn/kgDM) and group 3, HZn: (basal diet supplemented with 300 mg Zn/kgDM).

The results of this study showed no significant differences between the experimental groups in glucose, NEFAs, BHB, cholesterol, triglyceride, and insulin concentrations. Furthermore, the effect of zinc on the insulin to glucose ratio was not significant among the experimental groups (p < /em>>0.05). Supplementation of zinc-methionine significantly increased serum zinc concentration in ewes (p < /em><0.001). The area under the curve (AUC60, AUC120) was the highest for the control group and LZn and the lowest for HZn group (p < /em><0.05). The rate of glucose clearance in zinc-methionine supplement recipients was higher compared to the control group. The time to reach half maximal glucose concentration in zinc treated ewes was significantly lower than that of the control group (p < /em><0.001), indicating an improvement in insulin sensitivity and glucose metabolism.

Our findings indicate that Zinc is effective in improving the NEB and preventing insulin resistance in early lactation. It is possible that in sheep, the tissue responsiveness to insulin is enhanced with dietary Zn supplementation, and present findings suggest that dietary Zn-Met may improve energy balance and insulin resistance in lactating ewes.