“…The regulation of GH, T 3 and T 4 axes in fish involves multifactorial controls (MacKenzie et al, 1993;Riley et al, 1996;Gaylord et al, 2001;Peterson and Small, 2005;Peterson et al, 2009). Food intake and quality of feed, including amino acid profile, have a direct influence on growth-related hormone dynamics in several fish species (Matty, 1986) including red drum, Sciaenops ocellatus (MacKenzie et al, 1993), gilthead sea bream, Sparus aurata (Gómez-Requeni et al, 2003), rainbow trout, Oncorhynchus mykiss (Riley et al, 1996), chinook salmon, Oncorhynchus tshawytscha (Pierce et al, 2005), tilapia, Oreochromis mossambicus (Fox et al, 2010) and channel catfish, Ictalurus punctatus (Gaylord et al, 2001;Peterson et al, 2009). Some studies have reported a direct secretagogue effect of ARG on fish hormones, but these have mainly focused on its insulinotropic potential.…”