Effects of organic zinc supplementation in weaned calves

摘要

The aim of the study was to investigate the effect of organic zinc supplementation in calves on serum zinc (Zn) concentrations, selected metabolic profile indicators and serum immunoglobulin (Ig) concentrations. The trial included 2 groups (n = 10) of weaned female calves. The Zn-Methionin calves (group Zn-Met) were supplemented with 30 mg Zn-Met/kg dry matter (DM)/day (BIOPLEX (R) Zn, Alltech, USA) for 90 days; the control calves (group C) received the same diet without organic zinc supplementation. Compared to the control group, organic Zn treatment significantly increased serum Zn concentration (P < 0.05), superoxide dismutase (SOD) activity (P < 0.01) and total Ig (P < 0.01) in the group Zn-Met at the beginning (7 days from the start of Zn-Met supplementation) of the trial. At the end of the trial (day 90) serum total protein (TP) (P < 0.05), albumin (P < 0.01), urea (P < 0.01), SOD (P < 0.01), copper (Cu) (P < 0.05), Zn (P < 0.01) and Ig (P < 0.05) concentrations were significantly higher in the Zn-Met calves. In the control group alkaline phosphatase (ALP) activity was significantly (P < 0.01) higher on day 90. A positive correlation between zinc concentrations, ALP, and SOD activities in serum, and a negative correlation between zinc and copper concentrations were demonstrated. Dietary Zn-Met supplementation in calves markedly influenced the metabolic profile and serum immunoglobulin concentrations. Compared to the control group, the Zn supplemented group showed a significantly (P < 0.05) lower ALP and significantly greater SOD serum activity (P < 0.01) at the end of the trial. Total Ig concentrations were significantly higher in the Zn treated group (day 7: P < 0.01 vs. day 90: P < 0.05).