Ascorbic Acid Supplementation Improves Skeletal Muscle Growth in Pacu (Piaractus mesopotamicus) Juveniles: In Vivo and In Vitro Studies.

Bruna Tereza Thomazini Zanella,Pedro Luiz Pucci Figueiredo Carvalho,Bruno Oliveira Silva Duran,Isabele Cristina Magiore,Robson Francisco Carvalho,Edson Assunção Mareco,Rondinelle Artur Simões Salomão,Tassiana Gutierrez De Paula,Guilherme Gutierrez Pereira,Maeli Dal-Pai-Silva,Margarida Maria Barros,Igor Simões Tiagua Vicente

doi:10.3390/ijms22062995

Abstract

In fish, fasting leads to loss of muscle mass. This condition triggers oxidative stress, and therefore, antioxidants can be an alternative to muscle recovery. We investigated the effects of antioxidant ascorbic acid (AA) on the morphology, antioxidant enzyme activity, and gene expression in the skeletal muscle of pacu (Piaractus mesopotamicus) following fasting, using in vitro and in vivo strategies. Isolated muscle cells of the pacu were subjected to 72 h of nutrient restriction, followed by 24 h of incubation with nutrients or nutrients and AA (200 µM). Fish were fasted for 15 days, followed by 6 h and 15 and 30 days of refeeding with 100, 200, and 400 mg/kg of AA supplementation. AA addition increased cell diameter and the expression of anabolic and cell proliferation genes in vitro. In vivo, 400 mg/kg of AA increased anabolic and proliferative genes expression at 6 h of refeeding, the fiber diameter and the expression of genes related to cell proliferation at 15 days, and the expression of catabolic and oxidative metabolism genes at 30 days. Catalase activity remained low in the higher supplementation group. In conclusion, AA directly affected the isolated muscle cells, and the higher AA supplementation positively influenced muscle growth after fasting.

Highlights

Since in vitro studies allow the control of the environment by the modification of the culture media to evaluate the effect of a specific nutrient, we isolated and cultivated muscle cells from pacu to understand if ascorbic acid (AA) supplementation can affect muscle cell in nutrient restriction situation, regarding the influence of other tissues
Our study demonstrated decreased muscle cell and muscle fiber diameters and increased catabolic gene expression during nutrient deprivation and fasting situations in pacu
After high AA supplementation, we found an increase in pacu muscle cell and muscle fiber diameters, in vitro and in vivo increased anabolic and myogenic gene expression, and increased expression of mitochondrial genes combined with decreased Cat activity in vivo

Summary

Introduction

Since skeletal muscle is the edible tissue of these animals, aquaculture production represents a great agronomic activity to satisfy human consumption [3]. Fish represent a model to study skeletal muscle, since these animals can increase muscle mass both by adding new fibers, called the hyperplasia process, and by increasing the diameter of pre-existing fibers, referred to as the hypertrophy process. These characteristics highlight a contrast between fish and other animals as mammals, whereas amniotes do not present hyperplasia in juvenile and adult stages (reviewed in [4]). The regulation of myogenic genes that promote muscle cell proliferation and differentiation and the systems related to energy production, such as oxidative metabolism, can be affected by nutrient unavailability [11,12,13,14,15,16]

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Results

Conclusion