Effectiveness of Octopus (Octopus sp.) Ink Extract on the Growth of Catfish (Clarias sp.) Infected with Staphylococcus aureus

Catfish (Clarias sp.) is an economically important freshwater aquaculture commodity in Indonesia. However, bacterial infections can compromise fish health and growth performance, highlighting the need for natural feed additives that support sustainable aquaculture. Octopus (Octopus sp.) ink, a fishery by-product containing nutrients and bioactive compounds with potential antioxidant and antimicrobial properties, represents a promising alternative. This study aimed to evaluate the effectiveness of octopus ink extract as a natural feed additive in improving the growth performance of catfish challenged with Staphylococcus aureus. A 50-day experiment was conducted using a completely randomized design with five treatments and three replicates. The treatments comprised K+ (infected fish without extract), K− (uninfected fish without extract), and three extract supplementation levels: A (25 mL/kg feed), B (50 mL/kg feed), and C (75 mL/kg feed), with all supplemented groups subjected to bacterial infection. Growth performance was assessed through absolute weight gain, absolute length gain, specific weight growth rate, and specific length growth rate. Octopus ink extract supplementation significantly affected growth performance (P < 0.05). Treatment C produced the highest absolute weight gain (8.50 ± 0.06 g), absolute length gain (5.18 ± 0.33 cm), and specific length growth rate (1.27 ± 0.07%/day), whereas treatment B achieved the highest specific weight growth rate (2.75 ± 0.14%/day). These findings suggest that octopus ink extract has potential as a natural feed additive for catfish, with 75 mL/kg feed providing the most favorable overall growth performance under the experimental conditions.