Effect of organic zinc supplementation on growth, nutrient utilization,and plasma zinc status in lambs

Two experiments were conducted to investigate the effect of supplemental zinc (Zn) on performance, nutrient digestibility, and plasma Zn status in Zandi lambs. In experiment 1, 18 male lambs (BW = 21.30 ± 0.55 kg) were fed a basal diet containing 22.8 mg Zn/kg dry matter (DM) with no supplemental Zn (control) or 20 mg of supplemental Zn/kg of DM from Zn sulfate (ZnS) or Zn peptide (ZnP). Average daily gain and dry matter intake were higher for the lambs fed the diet supplemented with ZnP. Feed conversion ratio was significantly (P < 0.05) lower in the ZnP group compared to the control and ZnS groups. In experiment 2, an in vitro gas production technique was used to evaluate the effects of zinc source on the gas production parameters. Rate of gas production after 6 h and total production of gas after 24 and 48 h did not differ between groups. In vitro DM digestibility, short-chain fatty acids, and ME content were increased (P < 0.05) by ZnP supplementation when compared to the ZnS and control groups. The results of this study showed that feeding ZnP improves performance and digestibility of DM and could result in higher metabolizable energy and short-chain fatty acid yield.