Monthly Archives: March 2021

Cultivation intensification with a recirculation system tends to have a high stocking density and a large amount of feed, so that feed residue, metabolic waste, and oxygen consumption also increase. To speed up the decomposition of feed residue and metabolic waste, filtering is necessary, namely by means of a bioball. This study aimed to analyze the types and numbers of bacteria present in the bioball, to improve water quality and the optimal number of bioballs for bacterial living media. The study used a completely randomized design, with 1 factor, 5 levels of treatment and 3 replications. The treatment levels are: A=without bioballs (control), B=35 bioball filters per container, C=45 bioball filters per container, D=55 bioball filters per container and E=65 bioball filters per container. Silver pompano (Trachinotus blochii) fish specimens measuring 10-12.55 cm and a body weight of 24.3-28.9 g, were cultivated for 56 days, at a stocking density of 1 fish for a water volume of 4 L (a total of 20 fish in a volume of 80 L). During the rearing, fish were fed with Megami GR2 pellets with a composition of 46% protein, 10% fat, 2% crude fiber and 10% moisture content, 3 times a day adlibitum. The type and density of bacteria in the bioball was observed, together with the water quality parameters, such as: temperature, pH, dissolved oxygen, total ammonium nitrogen, nitrite and nitrate. The research data were analyzed statistically using ANOVA (P<0.05), Newman Keuls’s advanced test and multiple regression models, with the SPSS 17.0 software. The best treatment was found in the use of 55 bioball filters per containers, with a volume of 9.8 L, which gave a bacterial density of 667.67±1.53×105 CFU mL-1. The number of bioballs affected the bacterial density by 31.1%, the nitrogen absorption in fish by 16.5% and the filter media by 85.2%. The bacteriocidal types found in the filter media are Acinetobacter sp., Shewanella sp. and Nitratireductor sp. A salinity of 15‰ in the culturing media with a filter substrate of 55 bioball filters per container in the recirculation system gave the best bacterial density and water quality: temperature 28.6-29.10C, pH 7.6-7.8, dissolved oxygen (DO) 6.3-6.7 mg L-1, total ammonia nitrogen (TAN) 0.06-1.57 mg L-1, nitrite (NO2) 0.120-0.861 mg L-1 and nitrate (NO3) 0.93-3.07 mg L-1.