Changes in the Antioxidant and Mineral Status of Rabbits After Administration of Dietary Zinc and/or Thyme Extract.

Katarína Kucková,L'ubica Chrastinová,L'ubomíra Grešáková,Sylwester Ślusarczyk,Klaudia Čobanová,Adam Cieslak,Mária Polačiková,Margaréta Takácsová,Anna Kandričáková

doi:10.3389/fvets.2021.740658

Abstract

This study was aimed at determining the impact of organic zinc (Zn) and thyme extract (TE) administration, given alone or together for 6 weeks, on the antioxidant and mineral status (Zn, Cu, Fe, and Mn) in the plasma and tissues of growing rabbits. A total of 96 rabbits of age 35 days were randomly assigned to one of four treatment groups: a control group (C), a Zn group supplemented with dietary zinc (50 mg/kg), a TE group receiving thyme extract applied in drinking water (1 ml/L), and a Zn + TE group treated with both additives. Lipid peroxidation in the plasma was influenced by Zn intake and in the kidney was affected by both the Zn and TE treatment (P < 0.05). Zn supplementation led to a significant increase in glutathione peroxidase activity (P = 0.017), total antioxidant capacity (P = 0.009) and total thiol groups level (P = 0.047) in the kidney, with the highest values occurring in rabbits receiving the combination Zn + TE. Administration of TE influenced Zn content in the kidney (P < 0.001), while zinc intake decreased Cu concentration in muscle (P = 0.021). In conclusion, the simultaneous administration of organic Zn and TE positively affected the antioxidant response of kidneys and can be used for improving the antioxidant status of growing rabbits.

Highlights

Dietary zinc and herbal nutraceuticals are known for their antioxidant properties and protective role against oxidative stress in animals [1, 2]
The objectives of the present study were to determine the effect of dietary organic Zn supplementation (50 mg/kg diet) and/or thyme extract added to drinking water (1 ml/L water) on the activities of antioxidant enzymes, such as superoxide dismutase (SOD, Cu/Zn SOD), glutathione peroxidase (GPx) and catalase (CAT), lipid peroxidation, total antioxidant capacity and trace elements (Zn, Cu, Fe, and Mn) concentration in the plasma and tissues of rabbits
The average daily body weight gain was in the range of 38.7–41.5 g/d, and feed conversion ratios were within the range of 3.0–3.5 g/g

Summary

Introduction

Dietary zinc and herbal nutraceuticals are known for their antioxidant properties and protective role against oxidative stress in animals [1, 2]. Zinc is a redox inactive trace element and an important component of the antioxidant network because it acts as a cofactor of antioxidant enzymes, protects cell membranes against oxidative damage through stabilization of sulfhydryl groups, is involved in the regulation of glutathione metabolism, and is a strong inducer of metallothionein (MT) synthesis, which acts in the sequestration of the reactive oxygen species produced under stress conditions [3,4,5]. Zinc and Thyme Influence Antioxidant Status other dietary components; they may enable greater mineral absorption [6]. The intake of organic Zn glycinate increased the activity of zinc-containing Cu/Zn superoxide dismutase in the kidney of rabbits fed diets with a Zn dosage above the maximum EU authorized total contents (150 mg Zn/kg complete feed) [10, 11]

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