Effects of Eugenol on Water Quality and the Metabolism and Antioxidant Capacity of Juvenile Greater Amberjack (Seriola dumerili) under Simulated Transport Conditions

Abstract

This study investigated the effects of added eugenol on water quality and the metabolism and antioxidant capacity of the liver and gills of the greater amberjack (Seriola dumerili) during simulated transport. The juvenile fish (10.34 ± 1.33 g) were transported in sealed plastic bags containing different eugenol concentrations at a density of 24.79 kg/m3 for 8 h. The different eugenol concentrations were divided into five groups: 0 μL/mL (control group), 0.0125 μL/mL, 0.025 μL/mL, 0.0375 μL/mL, and 0.05 μL/mL, with three replicates of each. The results showed that 0.05 μL/mL of eugenol could significantly increase dissolved oxygen, but 0.025 μL/mL–0.0375 μL/mL resulted in a significant decrease in dissolved oxygen and significant increases in NH4+-N and NO2−-N. It was found that 0.05 μL/mL of eugenol caused significant up-regulation of the relative expression of CPT-1 in the liver, significant down-regulation of the relative expression of FAS and PK in the liver and gills, a significant increase in glycogen concentration, and a significant decrease in glucose concentration. This suggests that 0.05 μL/mL of eugenol could reduce the metabolic capacity of fish. In addition, 0.05 μL/mL of eugenol caused significant up-regulation of the relative expression of CAT and a significant decrease of MDA concentration in the liver. Meanwhile, the gills showed significant up-regulation of CAT relative expression, significant down-regulation of Keap1 relative expression, and a significant increase in GSH activity, resulting in a significant increase in MDA concentration when the concentration of eugenol reached or exceeded 0.025 μL/mL. This suggests that 0.05 μL/mL eugenol could improve the antioxidant capacity of fish and lipid peroxidation levels in the gills. In conclusion, the addition of 0.05 μL/mL eugenol could improve water quality, and the metabolic and antioxidant capacities of liver and gills, but it could also increase lipid peroxidation levels in the gills under transport conditions.

Efficacy and Physiological Responses of Payangka Fish (Ophieleotris aporos) to Anesthetization with Clove Oil

“…Otherwise, the highest concentration of clove oil (0.2mL/L of water) significantly (p<0.05) has a shorter time to anesthesia the payangka fish. Clove oil contains eugenol compounds which have antioxidant, antifungal, analgesic, and antiseptic activities (He et al, 2022). In general, clove oil was an efficient anesthetic at low concentrations (Fernandez et al, 2017).…”

“…Meanwhile, research conducted by Bahi et al, (2018) showed that administration of clove oil on gilthead seabream did not affect glucose levels. According to He et al, (2022), eugenol could reduce the metabolic capacity of fish, which is shown by reducing glucose concentration. Our recent study showed that the high concentration of clove oil and the length of time of immersing can increase plasma glucose.…”