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There is growing interest for using essential oils (EOs) in fish feed as they can improve fish health, growth, and productive yield. But, there is little information concerning their effects on fish flesh quality and whether EO residues can be found in flesh. The EO of lemongrass was recently demonstrated to increase the productive yield of silver catfish. Thus, the aim of this study was to evaluate the impact of lemongrass EO supplementation on physico-chemical properties, sensory acceptance, and stability during frozen storage of fish fillets. Silver catfish (Rhamdia quelen) were fed diets containing 0, 1, or 3 mL/kg of EO for 20 days. Fish were slaughtered, and fillets were stored at −20°C for 12 months and evaluated every 90 days. Dietary supplementation with EO did not affect proximate composition, fatty acid composition, or sensory acceptance of fish fillets. EO constituents (especially citral) were not detected in fish fillets. EO supplementation at 1 mL/kg appears to be more suitable to maintain physico-chemical changes similar to control during frozen storage. These data support the safety of lemongrass EO for use in aquaculture for human consumption purposes. [ABSTRACT FROM AUTHOR]

This study evaluated whether anesthesia with essential oil (EO) of Lippia alba (300 mg L-1 for 4 min) prior to electronarcosis (128 V m-1 × 300 Hz for 5 s) or hypothermia (ice/water slurry) could delay fish spoilage during chilled storage of whole fish. Silver catfish (Rhamdia quelen) were subjected to two different pre-stunning treatments (water or anesthesia with EO of L. alba) followed by two different stunning procedures (hypothermia or electrical stunning), yielding four groups (n = 32/group): water (control) + hypothermia, water (control) + electrical stunning, EO of L. alba + hypothermia, and EO of L. alba + electrical stunning. After stunning, fish were slaughtered by percussion and stored in ice. Preslaughter anesthesia with the EO of L. alba extended fish shelf life by delaying the loss of freshness (nucleotide degradation), growth of Enterobacteriaceae, and fish deterioration (sensory evaluation). Such preservative effect was most remarkable for fish that were subsequently submitted to electrical stunning, as they had the lowest demerit scores and greatest shelf life in the sensory evaluation. Our results showed that preslaughter anesthesia with EO of L. alba followed by electrical stunning can delay the loss of freshness and extend fish shelf life during chilled storage. [ABSTRACT FROM AUTHOR]