Avaliação do crescimento e produtividade de artemia alimentada com dietas de Chaetoceros muelleri (Lemmermann, 1898) floculadas com quitosana

Abstract

Flocculation is an inexpensive biomass separation method and can be used to produce microalgae concentrates of interest in aquaculture. However, depending on the flocculating agent chosen, the biomass can be contaminated. Chitosan is an organic biopolymer with flocculating properties and has shown promise in the separation of microalgae biomass. Thus, the aim of the present study was to evaluate the zootechnical performance of brine shrimp fed diets of Chaetoceros muelleri that were flocculated with chitosan. The marine microalgae C. muelleri was cultivated until the exponential growth phase, and then it was flocculated with chitosan to produce two concentrates: Pasty Flocculated Diet (DFP) and Lyophilized Flocculated Diet (DFL), which were compared with the Control Diet (DC), composed of fresh microalgae culture. Artemia was cultivated in nine tanks with an individual useful volume of 5 L, supplied with estuarine water filtered at 1 μm, salinity 33 g/L and constant aeration. A total of 1.5 g of brine shrimp cysts were weighed to populate all tanks. The duration of cultivation was 14 days. The animals fed with DC and DFP had length varying between, respectively, 0.71 ± 0.02 mm and 0.73 ± 0.02 mm (P > 0.05). The animals fed with DFL had a length of only 0.6 ± 0.02 mm, statistically smaller compared to DC and DFP. In the interval corresponding to days 4 and 8 of culture, the Specific Growth Rate (SCT) of artemia fed with DFP was 7.19 ± 0.54%, followed by CD with 6.79 ± 0.50% and DFL with 5.65 ± 0.65%. For the interval between days 4 and 12, a TBI of 10.68 ± 0.45% for CD and 11.31 ± 0.17% for PFP was observed, with no statistically significant difference between them (p > 0 .05). Artemia fed on DC showed a productivity of 956 ± 427 mg/L, while with DFP it reached a final productivity of 853 ± 248 mg/L (p > 0.05). Thus, the present study demonstrated that it is possible to feed brine shrimp with a diet based on C. muelleri flocculated with chitosan. This biopolymer did not contaminate the microalgal biomass and can be used to flocculate the microalgae C. muelleri