Towards Zero Zinc Oxide: Feeding Strategies to Manage Post-Weaning Diarrhea in Piglets

Simple Summary

Zinc oxide (ZnO) supplementation at pharmacological doses in post-weaning piglets is a consolidated practice that allows efficient control of post-weaning diarrhea (PWD), a condition exacerbated by Escherichia coli F4 (K88) infections. Far from being completely elucidated, the multifactorial ZnO mechanism of action is in all likelihood exerted at the gastrointestinal level. However, increasing environmental concerns are arising from prolonged ZnO use. This article reviews the utilization of ZnO in piglets, the biological rationale behind its powerful activity, and the emerging threats that are leading towards a significant reduction in its use. Finally, a wide analysis of the strengths and weaknesses of innovative alternative strategies to manage PWD at the nutritional level is given.

Abstract

Zinc oxide (ZnO) at pharmacological doses is extensively employed in the pig industry as an effective tool to manage post-weaning diarrhea (PWD), a condition that causes huge economic losses because of its impact on the most pivotal phase of a piglet’s production cycle. In a multifactorial way, ZnO exerts a variety of positive effects along the entire gastrointestinal tract by targeting intestinal architecture, digestive secretions, antioxidant systems, and immune cells. ZnO also has a moderate antibacterial effect against Escherichia coli F4 (K88), the main causative agent of PWD. However, the environmental impact of ZnO and new emerging threats are posing serious questions to the sustainability of its extensive utilization. To work towards a future free from pharmacological ZnO, novel nutritional approaches are necessary, and many strategies have been investigated. This review article provides a comprehensive framework for ZnO utilization and its broad mode of action. Moreover, all the risks related to pharmacological ZnO levels are presented; we focus on European institutions’ decisions subsequently. The identification of a novel, complete solution against PWD should be accompanied by the adoption of holistic strategies, thereby combining good management practices to feeding approaches capable of mitigating Escherichia coli F4 (K88) infections and/or lowering ZnO utilization. Promising results can be obtained by adjusting diet composition or employing organic acids, natural identical compounds, polyphenol-rich extracts, prebiotics, and probiotics.

Approach to Determination a Structure – Antioxidant Activity Relationship of Selected Common Terpenoids Evaluated by ABTS•+ Radical Cation Assay

Data available in the literature indicated various biological activities of terpenes. One of the most frequently investigated activities is the ability to scavenge free radicals. To date, studies based on the DPPH• method indicated conjugated double bonds as moieties responsible for antioxidant activity of selected terpenes. In order to verify this theory, studies based on 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS•+) were performed. The spectrophotometric investigations explicitly revealed relatively high antioxidant activity of terpenes possessing conjugated double bonds in comparison with substances without this structural element. It has been shown that the chain-breaking antioxidant activity of terpenes strictly depends on π bonds. TEAC values and percentage scavenging of the free radicals revealed that the most promising antioxidants are α-terpinene, ocimene, pulegone and farnesene. In order to explain the reaction between terpenes and ABTS•+ free radical cation, a possible antioxidant mechanism has been proposed.