Effectiveness of Octopus (Octopus sp.) Ink Extract on the Growth of Nile Tilapia (Oreochromis niloticus) Infected with Staphylococcus aureus

Octopus ink contains bioactive compounds with the potential to serve as natural immunostimulants in aquaculture. This study aimed to evaluate the effect of supplementing feed with octopus (Octopus sp.) ink extract on the growth performance of Nile tilapia (Oreochromis niloticus) infected with Staphylococcus aureus. A completely randomized design was employed, consisting of five treatments with three replicates each: a positive control (K+), a negative control (K−), and three experimental groups receiving octopus ink extract at doses of 50 (A), 100 (B), and 150 mL/kg of feed (C). The fish were reared for 50 days, and growth performance was assessed based on absolute weight gain, absolute length gain, specific growth rate (SGR), and specific length growth rate (SLGR). The results indicated that treatment B yielded the highest numerical values ​​for all growth parameters, with an absolute weight gain of 9.64 ± 0.32 g, an absolute length gain of 4.03 ± 0.32 cm, an SGR of 2.48 ± 0.03%/day, and an SLGR of 2.27 ± 0.03%/day. No significant difference was observed between treatments B and C regarding SLGR. These findings suggest that supplementing feed with octopus ink extract—specifically at a dose of 100 mL/kg—has the potential to enhance the growth performance of Nile tilapia infected with S. aureus. Consequently, octopus ink extract may be considered a promising natural feed additive for Nile tilapia aquaculture.