August 2021

Reducing dietary Zn levels in growing-finishing pigs does not affect their growth performance and carcass characteristics.

Trace minerals play an essential physiological role in the normal growth and health of animals. However, their accumulation in the soil due to supplementation at high levels is an increasing concern. It was hypothesised that due to the chemical properties of the trace mineral sources, the productive performance of grower‐finisher pigs fed hydroxychloride minerals would be higher than those fed sulphates when Zn and Cu doses are low. The objective of the present study was to evaluate the effect of two Zn supplemented levels and two Zn and Cu sources (sulphate and hydroxychloride) on growing-finishing pigs. An in vitro study comparing both sources of Zn was conducted and showed that the most critical interaction of Zn with phytic acid, and reduction in phosphorus (PP) solubility, was at pH 6.5 and with Zn sulphate. An in vivo study was performed with a total of 444 pigs ([Duroc × Landrace]×Pietrain; initial BW: 18.7 ± 0.20 kg). Animals were allotted in a randomized complete block design (2 × 2) factorial arrangement with two Zn and Cu sources and two Zn supplemental levels (20 and 80 mg/kg).

There was no effect of the interaction between mineral source × Zn level or Zn level on growth performance or carcass characteristics. Apparent total digestibility of Zn and Cu along with carcass yield was higher for pigs fed hydroxychloride than pigs fed the sulphate counterparts. Feeding low levels of Zn decreased Zn (45.5%) and Cu (18.5%) faecal excretion.

In conclusion, under commercial conditions, feeding growing-finishing pigs with Zn levels below those established by the European Union regulation did not affect growth performance and carcass characteristics. Reducing dietary mineral (Zn and Cu) content resulted in a lower faecal mineral excretion. Pigs fed sulphate minerals had improved performance during the grower period, while pigs fed hydroxychloride minerals showed an improved performance during the finishing period and a greater carcass yield and mineral digestibility than those fed sulphates.

Villagómez‐Estrada S, Pérez JF, van Kuijk S, Melo‐Durán D, Karimirad R, Solà‐Oriol D.
Effects of two zinc supplementation levels and two zinc and copper sources with different solubility characteristics on the growth performance, carcass characteristics and digestibility of growing‐finishing pigs.
Journal of Animal Physiology and Animal Nutrition. 2021; 105(1): 59-71.