Hepatic Zn (239 vs. 91, 83 μg/g, respectively) and mucosal and hepatic Mt concentrations were higher (P < 0.0001) for pigs drenched with 2800 mg Zn at 24 and 48 h than in baseline pigs or those without the Zn drench. Hepatic Zn concentrations at 48 h were significantly greater than those at 24 h (239 vs. 333 μg/g, respectively). In study 2, 24 and 48 pigs were fed 2000 or 150 ppm Zn as Zn oxide, respectively. Half the pigs fed 150 ppm Zn were drenched with 1535 mg Zn in a slurry similar to study 1. After 2 wk, the ADG was greater for pigs fed 2000 ppm Zn (0.27 kg) or 150 ppm Zn (0.23 kg) than those fed 150 ppm Zn plus 1535 mg Zn drench (0.15 kg; P = 0.001). After 2 wk, G:F was greater (P = 0.008) for these same 2 treatments. Utilizing the same treatments in study 3 (n = 32/ treatment) except one half of the pigs fed 2000 ppm Zn were switched to 150 ppm during wk 3. Overall ADG did not differ for pigs on any treatment.
In summary, 2000 ppm dietary Zn from Zn oxide stimulates growth during the first 2 wk following weaning, but a pharmacological Zn dose does not. The presence of Mt holding Zn in the mucosa for rapidly growing cells does not result in improved growth.
GM Hill, JE Link, JA Snedegar, and MJ Dawes, 2010. Journal of Animal Science, 87 (E-Suppl. 3):91.