Feasibility of using physarum polycephalum microplasmodial biomass as a feed for artemia franciscana

Abstract

Artemia is considered an essential basic diet in shrimp and fish larviculture, which accelerates the trend of developing commercial supplements to improve the nutritional value of them. However, these products (e.g., DHA Selco, fresh microalgae) are highly-priced and difficult to produce, concentrate, and store. Physarum polycephalum (a slime mold) is relatively rich in protein and lipid with considerable amounts of essential amino acids and unsaturated fatty acids. In addition, the trophic stage (plasmodia or microplasmodia) of this organism has no cell wall. These suggest a high potential for use in dietary supplements and functional foods. Thus, this study aimed to investigate the feasibility of feeding P. polycephalum microplasmodal biomass to Artemia franciscana. Newly-hatched Artemia nauplii were enriched for six hours in five diet treatments including DHA Selco (S), dry P. polycephalum microplasmodial biomass (D), fresh P. polycephalum microplasmodial biomass (F), DHA Selco mixed with dry P. polycephalum microplasmodial biomass (SD), and DHA Selco mixed with fresh P. polycephalum microplasmodial biomass (SF). After that, biochemical tests were conducted to evaluate the effects of these treatments on the nauplii’s growth performance and nutritional value (protein, carotenoids, lipid content, and fatty acid composition). Artemia enriched with the treatment of dry slime mold microplasmodial biomass showed the greatest performance growth (689.58 μm), followed by Artemia fed fresh slime mold microplasmodial biomass (660.31 μm) and Artemia fed Selco (658.49 μm). Regarding protein content and total carotenoids, the highest values were observed at SF-fed Artemia treatment (598.15 mg/g and 337.92 μg/g, respectively). D-fed Artemia had the second high in protein content (563.58 mg/g) but it showed the lowest carotenoids value (312.34 μg/g). Although lipid amount was significantly higher in Selco fed Artemia (229.17 mg/g) than in Artemia enriched with D (202.83 mg/g) and F (198.83 mg/g), there were no significant differences between Selco and the other two treatments that combined Selco and dry/fresh P. polycephalum biomass (211.50 mg/g and 209.67 mg/g, respectively). Based on these findings, this study suggests that P. polycephalum biomass cultured in a low-cost carbon source could be an alternative feed for Artemia enrichment.