 The objective of this study was to investigate the effects of varying levels of fish meal, FM, and salt supplementation on the growth performance, feed conversion ratio, and gene expression of two key proteins involved in nutrient transport in European sea bass, dysentrarchus labrax. The results showed that increasing the amount of FM in the diet had a positive impact on growth performance, while salt supplementation increased the expression of the peptid transporter gene, PEPT1, but did not affect the expression of the neutral amino acid transporter gene, SLC6A19. Additionally, the addition of salt to a diet containing a low level of FM improved feed intake, as well as specific growth rate and feed conversion ratio. This article was authored by Simona Ramaldi, Elena Bossi, Sheenan Harpers, and others.