Effects of dietary zinc and iron supplementation on mineral excretion, body composition, and mineral status of nursery pigs1,2

Abstract

Two experiments were conducted to evaluate the effects of dietary Zn and Fe supplementation on mineral excretion, body composition, and mineral status of nursery pigs. In Exp. 1 (n = 24; 6.5 kg; 16 to 20 d of age) and 2 (n = 24; 7.2 kg; 19 to 21 d of age), littermate crossbred barrows were weaned and allotted randomly by BW, within litter, to dietary treatments and housed individually in stainless steel pens. In Exp. 1, Phases 1 (d 0 to 7) and 2 (d 7 to 14) diets (as-fed basis) were: 1) NC (negative control, no added Zn source); 2) ZnO (NC + 2,000 mg/kg as Zn oxide); and 3) ZnM (NC + 2,000 mg/kg as Zn Met). In Exp. 2, diets for each phase (Phase 1 = d 0 to 7; Phase 2 = d 7 to 21; Phase 3 = d 21 to 35) were the basal diet supplemented with 0, 25, 50, 100, and 150 mg/kg Fe (as-fed basis) as ferrous sulfate. Orts, feces, and urine were collected daily in Exp. 1; whereas pigs had a 4-d adjustment period followed by a 3-d total collection period (Period 1 = d 5 to 7; Period 2 = d 12 to 14; Period 3 = d 26 to 28) during each phase in Exp. 2. Blood samples were obtained from pigs on d 0, 7, and 14 in Exp. 1 and d 0, 7, 21, and 35 in Exp. 2 to determine hemoglobin (Hb), hematocrit (Hct), and plasma Cu, (PCu), Fe (PFe), and Zn (PZn). Pigs in Exp. 1 were killed at d 14 (mean BW = 8.7 kg) to determine whole-body, liver, and kidney mineral concentrations. There were no differences in growth performance in Exp. 1 or 2. In Exp. 1, pigs fed ZnO or ZnM diets had greater (P < 0.001) dietary Zn intake during the 14-d study and greater fecal Zn excretion during Phase 2 compared with pigs fed the NC diet. Pigs fed 2,000 mg/kg, regardless of Zn source, had greater (P < 0.010) PZn on d 7 and 14 than pigs fed the NC diet. Whole-body Zn, liver Fe and Zn, and kidney Cu concentrations were greater (P < 0.010), whereas kidney Fe and Zn concentrations were less (P < 0.010) in pigs fed pharmacological Zn diets than pigs fed the NC diet. In Exp. 2, dietary Fe supplementation tended to increase (linear, P = 0.075) dietary DMI, resulting in a linear increase (P < 0.050) in dietary Fe, Cu, Mg, Mn, P, and Zn intake. Subsequently, a linear increase (P < 0.010) in fecal Fe and Zn excretion was observed. Increasing dietary Fe resulted in a linear increase in Hb, Hct, and PFe on d 21 (P < 0.050) and 35 (P < 0.010). Results suggest that dietary Zn or Fe additions increase mineral status of nursery pigs. Once tissue mineral stores are loaded, dietary minerals in excess of the body's requirement are excreted.

Effects of Tannic Acid Added to Diets Containing Low Level of Iron on Performance, Blood Hematology, Iron Status and Fecal Microflora in Weanling Pigs

“…The composition of feed ingredients provided by NRC (1998) suggested that limestone and monocalcium phosphate contained 3500 and 7500 mg Fe/kg. In agreement with our findings, Rincker et al (2005) had also noticed analyzed Fe values of 189 to 223 mg/kg in the nursery diets that were formulated to contain 50 to 60 mg Fe/kg and they had attributed this high Fe values in the diet to the higher Fe content of feed ingredients including limestone and monocalcium phosphate.…”

“…The Fe concentration of most nursery diets is in excess of the NRC (1998) postweaning dietary Fe requirement of 80 mg/kg. This occurs because many feed ingredients have a high Fe concentration, including monocalcium phosphate and limestone (Rincker et al, 2005). In our previous study we had noticed supplemental Fe (50 to 250 mg/kg) can linearly increase diarrhea incidence and fecal coliform count in weaned pigs (Lee et al, 2008).…”

Low doses of microencapsulated zinc oxide improve performance and modulate the ileum architecture, inflammatory cytokines and tight junctions expression of weaned pigs

“…Zinc oxide mechanism of action as growth promoter appears to go beyond the fulfillment of Zn nutritional needs, and it seems to be more related to improved intestinal health (Zhang and Guo, 2009). In fact, there is growing evidence that ZnO efficacy might be independent from absorption but rather it would act within the gut, as it is well established that above the requirements absorption and retention are no longer increased (Poulsen and Larsen, 1995;Krebs, 2000;Rincker et al, 2005). With this hypothesis in mind, it seems logical to assume that a controlled release of ZnO along the intestine through the use of slow-release techniques might improve its efficacy (Kim et al, 2012;Hu et al, 2013).…”

Bioaccumulation of ZnO-NPs in Earthworm Eisenia fetida (Savigny)

“…ZnO-NPs are used in industrial products including cosmetics (sun screens, foot care, ointments and over-the-counter tropical products), pigments and coatings (ultra violet [UV]) protection, fungicide in paints), mouth washes, electronic devices and catalysts [5]. ZnO-NPs have also been used as a dietary supplement in human and live stock because Zn can stimulate the immune system and act in an anti-inflammatory way [6,7]. Many in vitro studies have demonstrated that ZnO-NPs are toxic to mammalian cells and even more toxic than other nanoscale structures of metallic oxide [8][9][10].…”