Aquaculture Europe 2023

September 18 - 21, 2023


Add To Calendar 20/09/2023 14:00:0020/09/2023 14:15:00Europe/ViennaAquaculture Europe 2023


Stolz 1The European Aquaculture Societywebmaster@aquaeas.orgfalseDD/MM/YYYYaaVZHLXMfzTRLzDrHmAi181982


K. Chaiyasut1*, K. Gaffney1, P.A. Palma1, D. Leeming2, E. Jimenez-Fernandez3, H. Migaud4, R. Bickerdike5, J. Baily1, M.B. Betancor1

1University of Stirling, Stirling, FK9 4LA, Scotland, UK. Email:

2Biomar UK, North Shore Rd/Grangemouth Docks, Grangemouth FK3 8UL, Scotland, UK

3Otter Ferry Seafish, Tighnabruaich, ?Argyll, PA21 2DH, Scotland, UK

4Mowi Scotland Ltd., Stob Ban House, GlenNevis Business Park, Fort William, PH33 6RX, Scotland, UK

5Scottish Sea Farms Ltd., South Shian, Connel, PA37 1SG, Scotland, UK



Nucleotides have a wide variety of functions beyond their most recognized role as the basic building blocks of RNA and DNA. They provide and mediate energy metabolism, are key components of cell signalling, and are key enzymatic cofactors (Cosgrove, 1998), to name a few. While organisms can produce nucleotides without dietary input (Cosgrove, 1998), this process is metabolically expensive and direct provision may allow fish systems to react faster to challenges (Ringø et al., 2012). Therefore, nucleotides are generally considered semi-essential nutrients (Li and Gatlin, 2006) and beneficial during periods of rapid growth or high metabolic demands, such as larval stages or disease (Li and Gatlin, 2006). Taking their lead from human nutrition (Cosgrove, 1998Íž Li and Gatlin, 2006), aquaculture research has begun to explore the potential of nucleotides to be used as feed additives (Li and Gatlin, 2006). A wide range of nucleotide-based products have been used for a variety of fish species and have been shown to optimise cell proliferation, promote growth (Hossain et al., 2016), enhance immune response (El-Nokrashy et al., 2021) as well as improve gut integrity and function (de Cruz et al., 2020). However, the mode of action of nucleotides on these various functions has in many cases yet to be fully elucidated. The deployment of ballan wrasse (Labrus bergylta) from the hatchery to the net pen is a period of high stress and mortality, with increased exposure to environmental stressors and disease. Working closely with industry partners, this study will explore the use of nucleotides as health additives in developing functional feeds to support ballan wrasse during this period.

Materials and Methods

Ballan wrasse (38.4 ± 9.4g) were randomly distributed into twelve 350 L flow-through tanks (100 fish per tank). Tanks were allocated to one of four experimental diets: A control diet following the current standard commercial formulation for this species with no added nucleotides (NT0) and three treatment diets with increasing levels of nucleotide supplementation (NT1, NT2 and NT3) using the commercial product Rovimax NX (DSM Animal Health and Nutrition). Each condition was conducted in triplicate with fish fed the experimental diets to satiation for 8 weeks. At the end of the trial, samples from different tissues were collected for histological, vertebral health, molecular biology analysis as well as plasma. In order to examine the robustness of the fish after feeding the supplemented feeds, the fish were subjected to an immune challenge by intraperitoneally (IP) injecting lipopolysaccharide (LPS) of E. coli as pathogen-associated molecular patterns (PAMP) at the end of the experiment. Fish were sampled 24 hours post-LPS injection, with plasma and head kidney collected. Operational welfare indicators (OWI) were also scored at the end of the nutritional challenge and after the challenge.

Results and Discussion

Fish performance was generally good, with fish increasing weight on average 1.6 times compared to the start of the trial. After 8 weeks of feeding the experimental feeds, fish fed the non-supplemented feed did not display significant different body weight compared to fish fed nucleotide-supplemented feeds. No difference was also found in terms of survival, being 99.2 ± 0.7 % on average. The fish showed good OWI scores, though not significantly different among the experimental fish. No significant difference was found in the fish haematocrit, the hepatosomatic index, and liver histology at the end of the nutritional trial.

The preliminary results seem to indicate that nucleotide available from the non-supplemented commercial formulation covered the nutritional requirements for the general performance of ballan wrasse. Further results will be presented, including molecular markers’ response to the immune challenge, to ascertain the benefits of nucleotide supplement for the ballan wrasse subjected to an immune stressor, in order to prepare them for the cage transfer.


Cosgrove (1998) Nucleotides. Nutrition 14, 748–51.

de Cruz C et al. (2020) Efficacy of purified nucleotide supplements on the growth performance and immunity of hybrid striped bass Morone chrysops x Morone saxatilis. Fish & Shellfish Immunology 98, 868-874

El-Nokrashy et al (2021) Impact of nucleotide enriched diets on the production of gilthead seabream, Sparus aurata fingerlings by modulation of liver mitochondrial enzyme activitity, antioxidant status, immune gene expression, and gut microbial ecology. Aquaculture 535, 736398.

Hossain et al (2016) . Dietary effects of adenosine monophosphate to enhance growth, digestibility, innate immune responses and stress resistance of juvenile red sea bream, Pagrus major. Fish and Shellfish Immunology 56, 523–533

Li and Gatlin (2006) Nucleotide Nutrition in Fish: Current Knowledge and Future Applications. Aquaculture 251, 141-152.

Ringø et al (2012) Use of immunostimulants and nucleotides in aquaculture: a review. Journal of Marine Science: Research and Development 2, 1.