Effects of Supplemental Nucleotides, Taurine, and Squid Liver Paste on Feed Intake, Growth Performance, Serum Biochemical Parameters, and Digestive Enzyme Activities of Juvenile GIFT Tilapia (Oreochromis sp.) Fed Low Fishmeal Diets

This 8 week feeding trial evaluated the effects of three feeding stimulants (FS) on feed intake, growth performance, body composition, serum biochemical parameters, and digestive enzyme activities for juvenile GIFT tilapia fed low fishmeal diets. Four test diets were supplemented with 0, 16 g/kg taurine (Tau), 0.4 g/kg mixed nucleotides (Mix-NT), and 30 g/kg squid liver paste (SQLP) respectively, and fed to juvenile GIFT strain of Oreochromis niloticus (3.34 +/- 0.01 g). The results showed that feed intake (FI) significantly increased with SQLP. Specific growth rate (SGR) in fish fed SQLP or Mix-NT diet was significantly higher than that of the Tau and control group. The feed conversion ratio (FCR) ranged from 1.34 in the group fed Mix-NT to 1.50 in the group fed Tau, with no significant differences compared to the control group. Three feeding stimulants had no significant influence on whole body composition of tilapia. Fish fed Mix-NT diet showed significantly higher intestinal protease activity and intestinal amylase activity than that of other groups. High-density lipoprotein content in serum was significantly higher in fish fed SQLP diet than that of other groups. In conclusion, supplementation of 0.4 g/kg mixed nucleotides or 30 g/kg squid liver paste in low fishmeal diets could provide better growth performance for juvenile tilapia, and SQLP could act as an effective FS under these conditions. Supplementation of Mix-NT could reduce the FCR in these fish.