Stocking density of red tilapia (Oreochromis sp.) reared in a commercial biofloc system in Colombia

ABSTRACT Biofloc technology (BFT) has several advantages, such as low water supply requirements and apparent feed conversion ratio (FCR), and high densities. However, there is no information on adequate densities and their effect on the large-scale production of different species. In this study, we determined the effects of the stocking density of monosex red tilapia reared using BFT on the growth performance, water quality parameters, and chemical characteristics of fish on a large scale and under culture conditions in eastern Colombia. In total, six circular tanks (diameter: 14 m, height: 1 m, and capacity: 153 m³) were used in this investigation. Two stocking densities were considered: treatment 1 (T30: 30 fish/m³) and treatment 2 (T40: 40 fish/m³), in triplicate. The water quality parameters of the two treatment densities were within the normal ranges for the species, but dissolved oxygen decreased throughout the production process. The T30 and T40 treatments did not result in significant differences in growth performance. At the end of the trial, the FCRs were 1.6 and 1.7 from T30 and T40, respectively. Fishes raised at a lower density had a similar weight gain; however, their final biomass was not significantly different. BFT did not affect the nutritional characteristics of fish; the percentage of protein (%) in tilapia was 17.81% ±1% and 16.72% ±1% in the T30 and T40 groups, respectively. None of the fish were infected by Salmonella spp. or Vibrio cholerae. RESUMO Tecnologia de bioflocos (BFT) tem vantagens em termos de redução do fornecimento de água, redução da taxa aparente de conversão alimenta FCR e aumento das densidades. Entretanto, não há informações sobre densidade adequadas e seu impacto na produção em largas escala das diferentes espécies. Este estudo teve como objetivo determinar os efeitos da densidade de povoamento da tilápia vermelha masculinizada no BFT sobre desempenho produtivo, parâmetros de qualidade da água e características químicas dos peixes em larga escala e sob condições de cultivo no leste da Colômbia. Foram usados seis tanques circulares de 14 m de diâmetro, com capacidade de 153-m3, as densidades estudadas foram tratamento 1 (T30-30 peixes/m³) e tratamento 2 (T40-40 peixes/m³), em triplicado. Os parâmetros de qualidade da água das duas densidades estavam dentro das faixas normais para a espécie, mas o oxigênio dissolvido tendia a diminuir durante todo o processo de produção. As densidades de estocagem de T30 e T40, resp