Antioxidant and Anti-Inflammatory Effects of Different Zinc Sources on Diquat-Induced Oxidant Stress in a Piglet Model.

Guiping Guan,Jieping Guo,Jie Yin,Yulong Yin,Tiejun Li,Liuqin He

doi:10.1155/2020/3464068

Abstract

Zinc (Zn) plays a crucial role in reducing oxidative stress and diarrhea in postweanling piglets. This study is aimed at comparing the effects of zinc chelate of 2-hydroxy-4 methyl-thio butanoic acid (HMZn) and ZnSO4 on the oxidative stress in weaned piglets. A total of 32 piglets were randomly divided into 4 treatments: CON: basal diet+80 mg/kg Zn as ZnSO4; DIQ: basal diet+80 mg/kg Zn as ZnSO4; HMZn: basal diet+200 mg/kg Zn as HMZn; and ZnSO4: basal diet+200 mg/kg Zn as ZnSO4. On day 15, the DIQ, HMZn, and ZnSO4 groups were injected intraperitoneally with diquat except for the CON group. The trial lasted 21 days. The results showed that zinc sources did not influence the growth performance during the first 14 days. But HMZn increased activities of superoxide dismutase (SOD), glutathione peroxidase (GPX), and total antioxidant capacity (T-AOC) in serum (P < 0.05). After diquat injection, the fecal score was decreased in the HMZn group. Both HMZn and ZnSO4 increased the activities of GPX and T-AOC in serum and the relative mRNA expressions of hepatic and renal Nrf2, SOD1, and GPX compared with the DIQ group (P < 0.05). Moreover, the relative mRNA expression of inflammatory factors in the small intestine, liver, and kidney was downregulated; the phosphorylation of NF-κB protein was inhibited in the HMZn group compared with the DIQ and ZnSO4 groups (P < 0.05). In general, HMZn showed notable advantage over ZnSO4 in reducing diarrhea and improving antioxidant and anti-inflammatory ability in piglets challenged with diquat.

Highlights

Zinc (Zn), as an essential constituent of more than 200 enzymes involving antioxidant enzymes, plays important roles in their biochemical and pathophysiological functions [1]
Previous studies in humans and mice revealed that Zn deficiency from marginal to moderate led to growth retardation, immunity disorder, gastrointestinal impairment, and aggravated oxidative stress [20, 21]
It can be explained that additional Zn supplementation facilitated the synthesis of Zn-containing antioxidant enzymes, improving the defense ability against oxygen-free radicals, which is helpful in maintaining the intestinal health and reducing inflammatory processes after diquat challenge, and improving growth performance

Summary

Introduction

Zinc (Zn), as an essential constituent of more than 200 enzymes involving antioxidant enzymes, plays important roles in their biochemical and pathophysiological functions [1]. Zinc supplementation was demonstrated to significantly improve growth performance, antioxidant ability, and immune function of weanling pigs [3]. Weaning piglets are highly susceptible to weaned syndrome, including growth retardation, diarrhea, metabolic disorders, and even death, dietary Zn supplementation could improve growth performance in the weaning stress conditions [4,5,6,7]. Many forms of inorganic Zn (i.e., ZnSO4, ZnO) have been used in weanling piglets’ diets to improve growth performance in the last decades; for example, a pharmacological level of ZnO While there is certain disputation on bioavailability of Zn from different sources, an increasing number of reports show that megadose of in-feed inorganic Zn with low absorption efficiency has been the source of environmental pollution [4, 11, 12]

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