Toxicity assessment of the aqueous extract of brown algae Laminariocolax aecidioides using lux biosensors and micronucleus test when used in industrial aquaculture

Abstract

Extracts of brown macroalgae are widely used in pharmacology, cosmetology and the food industry, however, extraction of raw materials, on the one hand, undermines natural populations, and on the other hand, during plan-tation cultivation is an expensive production. The filamentous fast-growing algae Laminariocolax aecidioides is considered as a promising object for the preparation of extracts. It is supposed to use this extract as a biologically active additive in feed production for industrial aquaculture and therefore it is very important to check its toxicity on prokaryotic and eukaryotic cells. The effect of the extract on prokaryotic cells was evaluated using Escherichia coli K12 MG1655 lux biosensors (pColD-lux - DNA damage and pSoxS–lux - development of oxidative stress), and eukaryotic cells – by registering nuclear anomalies in the blood of bony fish (micronuclear test). Testing was carried out on fingerlings of the African clary catfish, a promising object of industrial aquaculture. It was revealed that the extract of the brown algae L. aecidioides did not directly damage DNA and did not cause oxidative stress, but caused the death of bacterial cells in high concentrations (50 and 100%), while the results of the micronucleus test showed the absence of toxic effects of the extract in all experimental variants on eukaryotic blood cells of Clarias gariepinus, the frequency of micronuclei did not exceed 1.5‰. The number of micronuclei can reach values of 30‰ against the background of the absence of a genotoxic effect, therefore, it can be assumed that the range of occurrence of micronuclei in red blood cells of catfish, taken for the absence of a genotoxic effect, is 0-30‰ per 1,000 blood cells.