THE EFFECT OF FERMENTED DUCK BONE FLOUR DOSAGE USING MIXED MICROORGANISMS ON INCREASING FEED NUTRITION AND GROWTH OF NILE FISH (Oreochromis niloticus)

Abstract

The high cost of fish feed in Indonesia, particularly in Sidenreng Rappang Regency, remains one of the main challenges in aquaculture development. This study aimed to determine the effect of different doses of mixed microorganisms in fermented duck bone meal on feed consumption, growth performance of Nile tilapia (Oreochromis niloticus), and hepatosomatic index (HSI). The research used a Completely Randomized Design (CRD) consisting of five treatments and three replications, resulting in 15 experimental units. The culture system used floating net cages measuring 2 meters in length, 1 meter in width, and 0.5 meters in height, each divided into five compartments measuring 40 × 40 cm. The treatments were as follows: A = 10% fermented duck bone meal, B = 15%, C = 20%, D = 25%, and E = 30%. Sampling was carried out weekly to monitor the weight of the fish and adjust feed allocation. Data were analyzed using analysis of variance (ANOVA), and if significant differences were found, the W-Tukey post hoc test was applied to identify the best-performing treatment. Water quality parameters, including temperature and pH, were measured daily using a digital thermometer and a pH meter. The results showed that Treatment D yielded the best proximate composition of feed with a crude protein content of 38.72%. In terms of growth and feed consumption, Treatment D also recorded the highest values, with a growth rate of 4.796±0.10 g and feed consumption of 11.73±0.13 g. However, the highest hepatosomatic index (HSI) was observed in Treatment A, with a value of 3.11±0.32.