Effect of quercetin on muscle growth and antioxidant status of the dark sleeper Odontobutis potamophila

Abstract

Quercetin is a flavanol beneficial in reducing fat, promoting muscle growth, and Anti-oxidation. To study its effects in freshwater fish, the full-length cDNA of the follistatin (FST) and myostatin (MSTN) genes of the dark sleeper Odontobutis potamophila were cloned for the first time. Juvenile individual O. potamophila was exposed to quercetin at one of four concentrations (0, 2.5, 5, and 10 mg/L) for 21 days. The expression level of MSTN which inhibits muscle growth in the quercetin solution was lower than in the unexposed control group. The genes that promote muscle growth are in TGF-β superfamily like FST, TGF-β1 (transforming growth factor-beta 1), and Myogenic regulatory factors (MRFs) like Myf5 (myogenic factor 5), MyoD (myogenic differentiation), MyoG (myogenin), were higher than in the control group. Apolipoprotein and growth hormone receptor transcription levels in the quercetin-treated fish were significantly lower than in the control group. The concentrations of triglyceride, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol in the muscle tissue decreased, and the lipid-lowering function of quercetin was also demonstrated at the biochemical level. In this study, we analyzed the mRNA levels of AKT, Keap1 (kelch-like ECH-associated protein 1), Nrf2 (NF-E2-related factor 2) oxidation-related genes in the Nrf2/ARE antioxidant pathway, and Malondialdehyde (MDA), catalase (CAT) activity and glutathione (GSH) content in the hepatopancreas of O. potamophila after quercetin treatment, the mRNA expression of AKT, Nrf2 and CAT activity and GSH content are higher than in the control group. Quercetin enhances antioxidant properties and positively affects muscle growth. The results showed that quercetin has no significant effects on the growth performance of O. potamophila, but is effective in increasing muscle growth rate and lowering muscle fat content.

Keywords: Odontobutis potamophila; antioxidant; flesh quality; muscle growth-related gene; quercetin.

FIGURE 1

Sequencing results and amino acid sequence analysis of transcription factor FST of Odontobutis potamophila. The black box indicates the ATG start codon; * indicates the termination codon; underlines indicate the Poly(A) plus tail signal; double underlines indicate the poly(A) sequence; red shading indicates a possible signal peptide region; blue shading indicates a possible TGFβ binding structural domain; green boxes indicate three possible repetitive follistatin structural domains; orange boxes indicate three duplicated Kazal structural domains; purple shading indicates possible nuclear localization signals; and yellow shading indicates possible N-glycosylation sites.

FIGURE 2

Sequencing results and amino acid sequence analysis of MSTN in Odontobutis potamophila. The black box indicates the ATG start codon; * indicates the termination codon; underlines indicate the Poly(A) plus tail signal; double underlines indicate the poly(A) sequence; red shading indicates possible signal peptide regions; blue shading indicates possible TGFβ binding structural domains; green boxes indicate three possible repetitive follistatin structural domains; orange boxes indicate three duplicated Kazal structural domains; purple shading indicates possible nuclear localization signals; and yellow shading indicates possible N-glycosylation sites.

FIGURE 3

The results of the similarity analysis. (A) FST: the solid red box shows the signal peptide; the solid blue box shows the TGFβ binding domain; the solid yellow box shows the kazoo-like 2; the solid green box shows the FST-like 3. (B) MSTN: the solid red box shows the signal peptide; the solid blue box shows the TGFβ binding domain; and the solid green box shows the TGFβ GDF8.

FIGURE 4

Evolutionary relationships of (A) FST and (B) MSTN in different species.

FIGURE 5

Three-dimension structures of FST and MSTN in O. potamophila. (A) Predicted 3D protein structure of transcription factor FST. (B) Predicted 3D protein structure of MSTN. (C) Predicted 3D protein structure of the MSTN homodimer. (D) Predicted 3D protein structure of the MSTN homodimer and the FST homodimer. (E) Schematic representation of the antagonistic relationship between MSTN and FST.

FIGURE 6

The effect of quercetin on the growth performance of Odontobutis potamophila. The bars indicate the mean weight ± SD (n = 3) of fish in the three treatment groups and the control. Statistical significance was taken as *(p < 0.05) and **(p < 0.01), compared with the control.

FIGURE 7

The effect of exposure to increasing concentrations of quercetin on triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), glutathione (GSH), Malondialdehyde (MDA) and catalase (CAT) in the muscles of O. potamophila. The bars indicate the Mean ± SD (n = 3). Statistical significance was taken as *(p < 0.05) and **(p < 0.01) compared with the control.

FIGURE 8

FST and MSTN gene expressions in various tissues of O. potamophila exposed to 0, 2.5, 5 and 10 mg/L of quercetin. The bars indicate the Mean ± SD (n ± 3). Statistical significance was taken as *(p < 0.05) and **(p < 0.01) compared with the intestine samples.

FIGURE 9

The effect of increasing concentrations of quercetin exposure on the relative expression of the FST, MSTN, A-I and GHR genes in the intestine, hepatopancreas, muscle and gill tissue of Odontobutis potamophila after 21 d. The bars indicate the Mean ± SD (n = 3). Statistical significance was taken as *(p < 0.05) and **(p < 0.01) compared with the control.

FIGURE 10

The effect of increasing concentrations of quercetin exposure on the relative expression of the (A): AKT, Keap1 and Nrf2 genes and (B): Myf5, MyoD, MyoG, and TGF-β1 genes in the muscle tissue of O. potamophila after 21 d. The bars indicate the Mean ± SD (n = 3). Statistical significance was taken as *(p < 0.05) and **(p < 0.01) compared with the control.