Optimisation of multispecies freshwater rotifer production using quail manure (Coturnix japonica) for aquaculture purposes in Bénin

Abstract

Sustainable management of animal manure includes, among other strategies, its valorisation. In aquaculture, animal excreta may be used to produce live prey, particularly zooplankton, which is essential for fish larval rearing. The study was conducted to determine the optimal dose of quail manure for multispecies rotifer production. Four quail manure doses (T1 = 0.15 g.L⁻¹; T2 = 0.30 g.L⁻¹; T3 = 0.60 g.L⁻¹; T4 = 1.20.g L⁻¹), previously evaluated for chicken manure, were tested alongside an unfertilised control (T0 = 0 g.L⁻¹). Each treatment was performed in triplicate using 5-L buckets filled to 3/5 of their volume with water and arranged in a completely randomised block design. Rotifer cultures were maintained for 16 days, following fertilisation of the culture media with quail manure and inoculation with a monospecific stock culture of the phytoplankton Scenedesmus quadricauda. Rotifer abundance was determined daily by microscopic counting using a Dollfus counting chamber. In parallel, key physicochemical parameters of the culture media, including temperature, pH, electrical conductivity and total dissolved solids, were measured daily to monitor water quality in relation to changes in zooplankton abundance. As results, the highest daily rotifer production (515 individuals.L^-1.j^-1) was recorded under treatment T2, followed by treatments T3, T1 and T4. In addition, treatment T2 presented the shortest rotifer population doubling time (19 h). Overall, a quail manure dose of 0.30 g L⁻¹, equivalent to 300 g m⁻³, was identified as optimal for multispecies rotifer production. Thus these findings contribute to the optimisation of large-scale zooplankton production through the valorisation of organic wastes, thereby supporting improved fish larval rearing within an integrated agropisciculture framework.