Anesthetic Efficiency of Three Medicinal Plant Oils for Aquatic Species: Coriander Coriandrum sativum, Linaloe Tree Bursera delpechiana, and Lavender Lavandula hybrida.

This study evaluated the potential of three essential oils (EOs) that were obtained from coriander Coriandrum sativum (CEO), linaloe tree Bursera delpechiana (BEO), and lavender Lavandula hybrida (LEO) as anesthetic agents. Convict Cichlids Amatitlania nigrofasciata (Günther 1867) were exposed to eight concentrations of anesthetic (50, 75, 100, 125, 150, 200, 250, and 300 µL/L). After exposure to the anesthetic, the fish were transferred to clean water to recover. All of the EOs produced an anesthetic effect after exposure to the compounds for 30 min at the minimal effective concentration (MEC), which was identified according to deep anesthesia (A5  < 3 min) and full recovery (R3  < 5 min) times. At 50 and 75 µL/L, the total loss of equilibrium was not observed for all tested EOs. The total loss of reflex was induced at a faster rate with higher concentrations of anesthetic in all groups. The recovery time generally increased as the concentration of the anesthetic increased. These findings suggest that CEO, BEO, and LEO are all novel potential anesthetics for aquaculture, and the optimal concentrations were identified as 150 µL/L (A5 ; 156 ± 1.7 s and R3 ; 165 ± 2.9 s), 125 µL/L (A5 ; 176 ± 3.5 s; R3 ; 125 ± 2.0 s), and 200 µL/L (A5 ; 20.1 ± 2.4 s and R3 ; 162 ± 3.4 s), respectively. When considering the active ingredients of EOs, this study also demonstrated that future studies should be focused on the major components such as linalyl acetate, 1.8-cineole, α-pinene, geraniol, and linalool. Their synergistic effects should be examined in herbal anesthetic treatments, since new commercial anesthetics will likely contain them.

Influence of Alpha and Gamma-Iron Oxide Nanoparticles on Marine Microalgae Species.

The effects of alpha-iron oxide (α-Fe2O3) and gamma-iron oxide (γ-Fe2O3) nanoparticles (NPs) on marine microalgae species (Nannochloropsis sp. and Isochrysis sp.) were investigated in this study. Both Fe2O3 NPs covered the surface of algae with the agglomerates of the nanoparticles. This form of physical NP toxicity significantly decreased the sizes of phytoplankton. Both NPs were toxic to the tested algal species, while α-Fe2O3 showed less toxicity than γ-Fe2O3 NPs for both algal species. A comparative analysis of growth data of the two algal species treated with α-Fe2O3 or γ-Fe2O3 NPs revealed that Isochrysis sp. are more sensitive than Nannochloropsis sp. Toxicity of these widely used NPs to primary producers forming the base of the food chain in aquatic environments might result in widespread adverse effects on aquatic environmental health.