Indicators of Zinc Status of Weanling Puppies Are Affected by Zinc Dietary Concentration

The objective was to assess Zn status of weanling puppies fed Zn methionine (ZnMET) or Zn oxide (ZnO) in a plant-based diet and to compare these 2 Zn sources for use in puppy diets. Two blocks of 15 puppies (28 d of age) were used in a randomized complete block design. Treatments included 1) control diet (50 mg Zn/kg); 2) control + 50 mg/kg Zn from ZnO; 3) control + 100 mg/kg Zn from ZnO; 4) control + 50 mg/kg Zn from ZnMET; and 5) control + 100 mg/kg Zn from ZnMET. Dogs consumed the control diet from d 1 to 7, and then were allotted to treatments from d 8 to 28. Growth, plasma Zn, alkaline phospha-tase isoenzyme profile, and metallothionein expression were determined. Data were analyzed as repeated measures. Change in plasma Zn was greater (P < 0.05) in dogs fed diets containing supplemental Zn compared with control. Weight gain was greater (P < 0.01) for dogs fed Zn-supplemented diets compared with control. No differences were noted for hair length, weight, or Zn deposition. Zinc supplementation of 50 or 100 mg ZnMET increased (P < 0.05) total alkaline phosphatase isoenzyme activity compared with that in dogs fed a control diet. These data suggest that supplementation of Zn may be beneficial in weanling puppy diets.