Influence of formula versus sow milk feeding on trace element status and expression of zinc-related genes in the jejunum, liver and pancreas of neonatal piglets

Abstract

Increasing litter sizes in modern swine production have raised an urgent need for artificial rearing strategies and formula feeding. The current experiment was conducted to study the influence of formula trace element concentration according to recommendations for weaned piglets on the mRNA concentration of zinc (Zn)-related genes in the jejunum, liver and pancreas of neonatal piglets. Eight artificially reared piglets were fed a cow-milk-based formula (Group FO) containing 100 mg Zn/kg dry matter. Eight of their sow-reared littermates (Group SM) were used as control. After 14 d, all 16 piglets were killed and the jejunum, liver and pancreas were evaluated for Zn, copper, manganese (Mn) and iron (Fe) concentration and mRNA concentration of metal and Zn-specific transporters, metallothioneins (MT) and interleukin 6 (IL-6). In Group FO the Zn concentration in liver tissue was increased (p < 0.05). Furthermore, Fe and Mn concentrations in liver and jejunal tissue were higher (p < 0.05) in Group FO, whereas neither Zn transporters nor MT in jejunal and pancreatic tissue showed differences between both groups. In the liver of Group FO, MT mRNA concentration was higher (p < 0.05), whereas Zn transporter protein 1 and divalent metal-ion transporter 1 (DMT1) mRNA concentration was lower (p < 0.05). Besides Zn-induced expression of transporters and MT, the significantly increased IL-6 expression in Group FO suggests the involvement of cytokine-mediated Mn and Fe sequestration in the liver and jejunum. The results revealed that dietary trace element concentration used in the study likely exceeded the requirements of neonatal pigs as reflected by homeostatic counter-regulation in different organs.