Aquaculture Europe 2023

September 18 - 21, 2023


Add To Calendar 20/09/2023 11:00:0020/09/2023 11:15:00Europe/ViennaAquaculture Europe 2023A PROTOTYPE WITH SEDATIVE PROPERTIES BASED ON NATURAL COMPOUNDS TO UPGRADE WELFARE IN LIVE-FISH TRANSPORT: AMELIORATION OF STRESS RESPONSES IN SEABASS Dicentrarchus labraxStrauss 3The European Aquaculture Societywebmaster@aquaeas.orgfalseDD/MM/YYYYaaVZHLXMfzTRLzDrHmAi181982


Sara Cartan1* , Ismael Jerez-Cepa1, Javier Feito2, Juan Antonio Martos-Sitcha1, Juan Miguel Mancera1

1Department of Biology, Faculty of Mar ine and Environmental Sciences, University Institute of Marine Research (INMAR), International Campus of Excellence in Marine Science (CEI?MAR), University of Cádiz, Spain

2 R&D Aquaculture manager, TecnoVit (FARMFaes group)




In a context of global change and increased food demand, the growth of aquaculture production must guarantee animal welfare.  Handling or transport operations  activate the stress responses, wh ich may compromise the integrity and general  welfare  status of fish.  To improve these  processes,  the use of anaesthetics  has been proved useful to reduce the possible adverse effects.

MS-222 or benzocaine are s ynthetic chemicals  commonly employed as anaesthetics in aquaculture. H owever, their  use is controversial due to human safety issues and the physiological side- effects that induce in fish. Essential oils  (EOs) derived from plants have been studied for this purpose, but its use might be problematic because of its compositional variability and effectiveness. Therefore, the use of  synthetic nature-identical compounds  (such as eugenol, menthol or thymol) , the  bioactive molecules  naturally present in tho se EOs, is a promising approach to develop new se dative strategies to improve operational processes in aquaculture.

 For this purpose, th is study assesses the effectiveness of a prototype with sedative properties (TecV2, developed by TecnoVit-FARMFaes Ltd.) in seabass (Dicentrarchus labrax) for a live transport of 3 and 6 hours.

Materials and methods

Seabass juveniles ( D. labrax) ( n = 72 ,  weight =  48.9 ± 18.4 g ) were placed into 15 L-tanks and distributed in four different experimental groups in triplicate : i ) 3 h transport without sedation (CTRL-3H) ; ii) 3 h transport with  10 ppm of TecV2 prototype; iii) 6 h transport without sedation ;  and iv ) 6 h transport with 10 ppm of TecV2 prototype. Prototype concentration was selected according to previous tests.

 Transport simulations took 3 and 6 h respectively . At the end of stressing trials,  half of the animals  from each tank  were euthanized and sampled (n = 9).  The remaining fish were transferred in to clean water tanks to determine their status after 24 h of  recovery. Additionally, 9 fish were euthanized and sampled before any manipulation (basal conditions). Fish were euthanized with an overdose of 2-phenoxyethanol (1 ppt ). Plasma s amples were taken to determine changes on plasmatic secondary stress responses (cortisol , glucose, lactate, etc.). Liver was also excised to assess changes in the intermediary metabolism of amino acids, lipids and carbohydrates.

 Tanks were well aerated  every  90 min until oxygen full-saturation. Oxygen levels were monitor ed and remained above 5 ppm during the whole simulation periods. Temperature was also monitored and remained around 19  ± 1 ºC.


 Our results  showed that both  live transport simulations for 3 and 6 h, were effective to activate stress responses in the seabass juveniles ( D. labrax) . Furthermore, these responses were modulated by t he addition of  the sedative prototype TecV2 to the water.

After 3 h transport  an increase on  plasmatic  glucose was observed, a common secondary stress response triggered by cortisol elevation. However, t his response was  ameliorated by the use of TecV2 , together  induced a reduction on lactate and protein levels.

 The  6 h transport induced a greater disturbance on stress parameters. At this point,  non-sedated fish ha d overco me stress  situation, so plasma hyperglycaemia was not detected . However, this response  was  observed on sedated  fish after 6 h of transport,  probably because of TecV2 sedation effect was lowering .  Protein and triglycerides (TAG) levels were lower in non-sedated fish , so  TecV2 was useful to maintain these  energetic sources in plasma. Alternatively, amino acids levels did not return to initial values after recovery and values were even lower than those observed during stress. However, the r eduction  after recovery on amino acids levels was lower when TecV2 was used. Hepatic carbohydrate and l ipid metabolism was also altered and an increase on TAG levels after 24 h was observed. These results are in concordance with the results of enzymatic activity determined.

 In conclusion, TecV2 has the potential to be used as sedative for the  live transport of seabass juveniles, especially for a 3 h transport, since it reduces energy mobilization.


 De Freitas Souza, C., et al. 2019. Essential Oils as Stress-Reducing Agents for Fish Aquaculture: A Review. Frontiers in Physiology. 10: 785.

Schreck, C.B., Tort, L. 2016. The concept of stress in fish. In: Schreck, C.B., Tort, L., Farrell, A.P., Brauner , C.J. (Eds.), Fish Physiology: Biology of Stress in Fish. Elsevier. pp. 1-34

Sneddon, L., Wolfenden, D. and Thomson, J. 2016. Stress Management and Welfare. In: Schreck, C.B., et al. (Eds.), Fish Physiology: Biology of Stress in Fish. Elsevier. pp. 463539

Zahl , Inger Hilde, Ole Samuelsen , and Anders Kiessling . 2012.  Anaesthesia of Farmed Fish: Implications for Welfare. Fish Physiology and Biochemistry . 38. pp. 20118.