Dietary Chlorogenic Acid Improved Muscle Quality, Antioxidant Capacity, and Pro-Inflammatory Responses of Blackspotted Croaker Protonibea diacanthus

The widespread use of commercial feeds with high-fat content in aquaculture may lead to oxidative stress and inflammation in fish during culture, which may cause changes in fish muscle texture. Therefore, mitigating oxidative stress and inflammation during fish farming holds paramount importance in improving fish muscle quality. In this study, we investigated the effect of different dietary levels of chlorogenic acid (CGA; 0, 100, 200, 400, 800, 1600 mg/kg diet, P1-P6) in commercial diets on the muscle of blackspotted croaker (Protonibea diacanthus) through an 8-week feeding trial in open sea cages. The results showed that high dietary CGA levels (P5-P6) could significantly reduce muscle oxidative stress and inflammation (P < 0.05). Muscle toughness (hardness, chewiness, shear force, and gumminess) improved significantly as CGA levels increased (P < 0.05). It was also observed that the gap of muscle fiber was significantly reduced, while the muscle fiber density was significantly increased with the increase of CGA level (P < 0.05). Notably, dietary CGA also had a significant effect on collagen content in the muscle (P < 0.05), which may also be a crucial factor affecting muscle texture. Furthermore, it was found that the reduction of inflammation and increase of collagen deposition in muscle by dietary CGA may be related to the upregulation of transforming growth factor beta (TGF-β) signaling pathway. Finally, it can be concluded that a dietary CGA supplementation of 1173.11 mg/kg is suggested for the aquaculture of P. diacanthus, based on the muscle texture quality.