Strategies of trace mineral supplementation for swine development and sustainibility

Abstract

For many years, the pharmacological use of trace elements such as Zn and Cu generated positive effects in the pig industry, by stimulating pig growth and controlling intestinal dysbiosis, especially in weaned piglets. However, their excessive excretion into the environment has put pressure on swine nutrition to find alternative strategies in the supply of trace minerals. The objective of this dissertation is to explore the effects of reducing trace mineral doses through different sources on animal growth and feed efficiency, as well as on fecal excretion levels and antimicrobial resistance rates, under commercial conditions. Reducing the levels of commercial Zn and Cu supplementation through highly available sources may represent an alternative strategy to reduce the risks of environmental contamination. Therefore, in Chapters III and V, two experiments were performed to evaluate reduced levels of Cu and Zn in weaned and growing pigs, respectively. The results showed that reducing Cu levels (15 mg/kg) on post-weaning diets for six weeks impairs the growth of pigs, with at least 1 kg of body weight, even in the presence of the phytase enzyme and particularly with a sulfate source. While the reduction of Zn (20 mg/kg) and Cu (15 mg/kg) at nutritional doses in grower diets, with phytase enzyme, does not affect the performance or the composition of the carcass, but it does reduce the mineral fecal excretion. Stimulating early feed consumption after weaning is of great interest to the swine industry. In Chapter IV, two experiments were conducted to study the pig preference for Cu doses and sources. When pigs are given a choice between nutritional levels (15 mg/kg) or reasonably high levels of Cu (150 mg/kg), they prefer the latter, probably to restore Cu homeostasis, and as a positive effect of the neuroendocrine feedback of Cu on feed consumption. Regarding Cu sources, pigs preferred to consume diets supplemented with hydroxychloride source instead of sulfate, probably due to the less bitter taste attributed to its chemical solubility differences. The gestation of hyperprolific litters (>30 pigs/sow/year) generates tremendous pressure on sow and litter performance. In Chapter VI the effect of partial substitution of inorganic sources by organic forms, as well as an additional reduction of dietary TM, on reproductive performance and fetal programming of the offspring was evaluated. It was detected for the first time that the supplementation of mothers with a combination of organic and inorganic minerals improves the neonatal expression of several functional genes involved in immune (TGF-β1, HSPB1), barrier (ZO1, MUC2, CLDN15), antioxidant (GPX2, SOD2), and digestive (CCK, IGF1R) function, especially in the smallest piglets of the litter. Taken together, reducing dietary levels of Zn and Cu, mostly through hydroxychloride source, decreases total fecal excretion and probably pressure on bacteria to develop antimicrobial resistance mechanisms, although performance and physiological state of weaned piglets are seriously affected. Maternal nutrition with a partial supplement of organic minerals is a valuable strategy to counteract the physiological disadvantages on hyperprolific litters, especially in the smallest pigs

Date of Award	27 Sept 2021
Original language	English
Awarding Institution	Universitat Autònoma de Barcelona (UAB)
Supervisor	Jose Francisco Perez Hernandez (Director) & David Sola Oriol (Director)