Feeding Nile tilapia with artificial diets and dried bioflocs biomass

ABSTRACT. The effects of supplying dried bioflocs biomass to Nile tilapia juveniles were investigated in the present work. Fish were stocked in experimental rearing tanks for eight weeks. Selected variables of water quality, growth performance and effluent quality were evaluated. Fish were given different combinations of artificial diets and biofloc biomass, in wet (in natura) or dry form. As the supply of artificial diet decreased, the allowance of biofloc biomass increased in the same proportion. Biofloc biomass was produced in two 500-L tanks that received daily applications of dry molasses to adjust the C: N ratio of the water to 15: 1. The concentration of nitrite in water was only reduced in the tanks receiving wet bioflocs. The fish growth performance was poorer in the tanks that received dried biofloc biomass than in the tanks with wet biofloc biomass. Given the lack of positive results, there is no justification to dry the biofloc biomass aiming at delivering it as a dry biomass to reared fish.

摘要
本研究旨在探究投喂干燥生物絮团（biofloc）生物质对尼罗罗非鱼幼鱼的影响。试验将尼罗罗非鱼幼鱼放养于实验养殖水槽中，养殖周期共计8周。研究人员对水质、生长性能及养殖尾水水质的多项选定指标进行了评估。试验组设置了不同配比的人工配合饲料与生物絮团生物质投喂方案，生物絮团生物质分为湿态（新鲜原生状态）与干态两种形式，且随着人工配合饲料投喂量的降低，生物絮团生物质的投喂量按相同比例同步提升。生物絮团生物质在两个500升的养殖水槽中制备，每日添加干燥糖蜜以将水体碳氮比调节至15:1。仅在投喂湿态生物絮团的水槽中，水体亚硝酸盐浓度得以降低。投喂干燥生物絮团生物质的水槽组，其尼罗罗非鱼生长性能劣于投喂湿态生物絮团生物质的水槽组。鉴于本研究未获得阳性试验结果，并无必要将生物絮团生物质干燥后，以干态生物质形式投喂给养殖鱼类。