Effects of phosphatidic acid on growth and antioxidant capacity in juvenile turbot, Scophthalmus maxius L., fed with high plant protein‐based diets

Abstract Replacement of fish meal with high plant protein meal leads to reduced growth performance and health issues in farmed fish. Supplementation of functional additives has been proposed as a potential strategy to alleviate the negative effect of plant protein replacement. In this study, the effects of phosphatidic acid (PA) on growth and antioxidant capacity in juvenile turbot fed with high plant protein‐based diets were evaluated. An 11‐week feeding trial was performed using diets containing 0 (CON group), 0.05, 0.1, or 0.5% PA. The results showed that adding 0.5% PA could significantly improve the growth performance of turbot without affecting feed intake. Moreover, supplementation of 0.5% PA significantly increased the mRNA level of igf‐1 in liver. The condition factor was also enhanced in PA addition groups. The activity of lipase was increased by PA supplementation, while no difference was observed in amylase and trypsin activity. Supplying PA significantly reduced the content of malondialdehyde. Furthermore, the mRNA levels of superoxide dismutase (sod), glutathione peroxidase (gpx), and peroxiredoxin 6 (prx6) were enhanced in 0.1 and 0.5% PA groups. Our results showed that PA might be a functional additive for aquafeed with growth‐promoting and antioxidative effects.