Bioavailability of Different Zinc Sources in Pigs 0–3 Weeks Post-Weaning

SIMPLE SUMMARY: The bioavailability of dietary zinc (Zn) in pigs is of importance for the Zn supply to the pig but also for Zn excretion through manure to the environment. The bioavailability of added Zn may differ according to the source of Zn applied but is also affected by other dietary components. The aim of this study was to determine biomarkers of Zn bioavailability (Zn digestibility and serum Zn status) following six different sources of Zn added at 100 mg/kg feed (two of the sources were also provided at 1000 mg/kg) and their effect on the productivity and faecal consistency score in piglets 0–3 weeks after weaning day 28. The digestibility of Zn on day 14 post-weaning was negative for all six Zn sources when added at 100 mg Zn/kg, indicating insufficient Zn supply. The Zn digestibility at 100 mg Zn/kg was affected by the Zn source but was not lower for traditional inorganic Zn oxide and Zn sulphate compared with processed inorganic or chelated organic sources of Zn. However, there were no differences in the serum Zn status, feed intake, gain or probability of diarrhoea depending on the Zn source when supplied at 100 mg/kg. ABSTRACT: The bioavailability of dietary zinc (Zn) in pigs may differ according to the Zn source and is affected by other components in the diet. The aim was to determine the biomarkers of Zn bioavailability (apparent total tract digestibility of Zn and serum Zn status) following six different sources of added Zn and their effect on the performance and faecal consistency score in piglets 0–3 weeks after weaning on day 28. The sources of Zn were Zn oxide (ZnO), Zn sulfate (ZnSO(4)), porous ZnO, Zn-glycinate, amino acid-bound Zn and hydroxy covalent-bound Zn added at 100 mg/kg (ZnO and ZnSO(4) also added at 1000 mg/kg), in a total of eight treatments (n = 12/treatment). Pigs were individually housed, and titanium dioxide was included as an indigestible marker in the feed. The digestibility of Zn on day 14 post-weaning was negative for all six Zn sources at 100 mg Zn/kg, indicating insufficient Zn supply. The digestibility of Zn differed according to the Zn source, but the digestibility of Zn from ZnO and ZnSO(4) did not differ between processed inorganic or chelated organic sources of Zn. However, the differences in Zn digestibility between Zn sources were not reflected as differences in the serum Zn status, feed intake, gain or probability of diarrhoea.