Nanoencapsulated Clove Oil Applied as an Anesthetic at Slaughtering Decreases Stress, Extends the Freshness, and Lengthens Shelf Life of Cultured Fish

Abstract

In the aquaculture industry, fish are stunned using a wide range of methods, but all of them trigger stress responses and affect the fish flesh quality. Chilled water is considered one of the most efficient methods, but even this is not a stress-free experience for the fish. Anesthetics included in the ice slurry or in water could decrease this stress and delay the loss of flesh quality. In this work, we analyze the effect of clove oil (CO) nanoencapsulated in β-cyclodextrins (β-CD) (CO + β-CD), incorporated in the stunning bath, on the stress response and the organoleptic attributes of fresh marine and freshwater fish from four economically important fish species: Atlantic salmon, European seabass, Nile tilapia, and Rainbow trout. CO + β-CD reduces the time required to induce anesthesia, independently of water salinity, habitat or water temperature. The plasmatic glucose and cortisol levels decreased in all four species, although the concentrations of CO varied between species. Moreover, plasmatic lactate level differed between the marine and freshwater fish. The use of CO + β-CD extended the shelf life of fish from all the species studied (by 3–7 days). In conclusion, using CO encapsulated in β-CD for anesthetizing fish can be regarded as an improved fish-stunning technique that reduces the anesthesia-induction time, decreases the stress response, and extends the shelf life of fresh fish.

Working towards a conservation plan for fish parasites: Cyprinid parasites from the south African cape fold freshwater ecoregion as a case study

“…Although this may work for larger fish, smaller fish may prove to be more complicated and may require a suitable chemical agent (such as clove oil or MS-222). Although a natural agent such as clove oil has been shown to be a good and environmentally friendly anaesthesia agent for fishes ( Keene et al, 1998 ; López-Cánovas et al, 2020 ), to our knowledge no studies have been conducted on whether these chemicals have an impact on the ability to successfully retrieve and study ectoparasites for taxonomic purposes and warrants further research.…”

Clove Oil-Nanostructured Lipid Carriers: A Platform of Herbal Anesthetics in Whiteleg Shrimp (Penaeus vannamei)

“…Similar findings have been reported for clove oil anesthetics in Piaractus brachypomus [ 43 ]. Importantly, the anesthetic efficacy is dependent on the eugenol’s solubility in lipids, as solubility enables the eugenol to pass through the cell wall of the gills [ 24 , 44 ]. Coating anatomic structures, especially gill epithelial cells, with oily clove oil or eugenol could lead to prolonged anesthetic effects.…”

Twenty Years of Research in Seabass and Seabream Welfare during Slaughter

“…The use of anaesthetics in ice slurry produced different results in seabass and seabream. While plasma lactate levels in seabass stunned with clove oil were higher than in ice slurry [ 55 , 56 ], they were lower in seabream (Lopez-Cánovas et al, 2019). Furthermore, both plasma glucose and cortisol levels were lower after adding clove oil to seabream [ 42 ] or seabass [ 56 ], but only under experimental conditions, with no significant variations in serum cortisol levels detected under industrial farm conditions, most likely due to greater individual variability.…”