Nitrite Stress Induces Oxidative Stress and Leads to Muscle Quality Decreased in Wuchang Bream (Megalobrama amblycephala Yih) Juveniles

Rong Tang,Chenzhi Lin,Zhenyi Hu,Chenglong Qi

doi:10.3390/w14020160

Abstract

To determine the effects of nitrite exposure on muscle quality and physiological functions in Wuchang bream (Megalobrama amblycephala), we exposed M. amblycephala juveniles to acute nitrite (0, 1, 5, 10, 20 mg/L), and the muscle and blood samples were measured at 12, 24, 48, and 96 h. The results showed that when exposed to nitrite for 12 h, the concentrations of blood glucose, cortisol, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) in the 20 mg/L experimental group had the maximum value. The activity of lactate dehydrogenase (LDH) increased significantly in a dose-dependently manner and peaked at 96 h in the 20 mg/L group. During 96 h of exposure to nitrite, the total antioxidant capacity (T-AOC) and catalase (CAT) activity in the liver of the 20 mg/L experimental group were significantly higher than those of the control group, while the concentration of muscle glycogen showed a downtrend. At 12 h and 96 h, the hardness of the four experimental groups were significantly higher than that of the control group. Our research shows that acute sodium nitrite exposure will not only cause oxidative stress and decreased muscle quality in M. amblycephala juveniles but also will be accompanied by changes in serum biochemical index, liver antioxidant capacity, muscle physiological characteristics, and muscle physical characteristics. Preliminary speculation may be that acute nitrite exposure may cause M. amblycephala juveniles to choose to reduce muscle quality and activate antioxidant systems.

Highlights

With the increase in total production, the aquaculture industry pays more and more attention to muscle quality
It was reported that the increase in glucose, glycogenolysis, and lactate is caused by increased energy demand and anaerobic metabolism under tissue hypoxia caused by exposure to nitrite [2]
At 48 h, there was no significant difference in muscle glycogen concentration between the control group and the experimental groups (Figure 3a)

Summary

Introduction

With the increase in total production, the aquaculture industry pays more and more attention to muscle quality. The body’s metabolism is usually closely related to muscle quality. In order to maintain the homeostasis in fish and resist stress, it always requires a lot of energy consumption. A large amount of metabolic waste is accumulated. High levels of nitrite exposure cause considerable stress in fish, and its toxicity manifests in physiological change, tissue damage, and cell injury [1]. It was reported that the increase in glucose, glycogenolysis, and lactate is caused by increased energy demand and anaerobic metabolism under tissue hypoxia caused by exposure to nitrite [2]

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Conclusion