Plasma and tissue Zn enrichment altered by different sources of Zn using stable isotopes in weaned male Holstein calves facing dietary antagonism

Zn-methionine hydroxy analog chelate (Zn-MHAC) as a pulse dose. Blood was collected via catheters before isotope administration and 0.25, 0.5, 0.75, 1, 2, 3, 4, 5, 6, 8, 10, 12, 24, 30, 36, and 48 h after isotope administration for determination of isotope enrichment. Calves were euthanized 48 h after isotope administration and target tissues harvested, weighed, and sampled for determination of isotope enrichment. Though dry matter intake differed, calves receiving the high diet (11.3 ± 0.2 g S/d) consumed 2.9 times more S than low diet (3.9 ± 0.2 g S/d). Tissue isotope enrichment decreased with high S diet for the following tissues: rumen, reticulum, omasum, duodenum, jejunum, ileum, kidney, and lung. Tissue isotope enrichment was greater with Zn-MHAC compared with Zn-Gly for the following tissues: rumen, reticulum, omasum, abomasum, duodenum, jejunum, ileum, kidney, lung, heart, spleen, and thymus. A significant interaction of S concentration and Zn source was observed for rumen and omasum. The impact of high dietary S on tissue Zn isotope enrichment demonstrates efficacy of this antagonistic model in ruminants. Moreover, changes in Zn enrichment of the splanchnic tissues suggests a high metabolic rate for Zn. Finally, the improved enrichment from Zn-MHAC demonstrates greater tissue Zn incorporation regardless of antagonism presence when compared with Zn-Gly.