IMPROVING PERFORMANCE OF SENEGALESE SOLE THROUGH DIET SUPPLEMENTATION WITH CURCUMIN EXTRACT
Introduction
Senegalese sole (Solea senegalensis ) is an emerging species for Southern European aquaculture. However, sole aquaculture faces bottlenecks regarding the development of strategies to control infectious diseases and the optimization of feeding and nut rition to improve growth rates. The growth performance of sole early life stages is highly dependent on nutritionally balanced diets . Diverse plant extracts containing bioactive compounds (e.g. polyphenols) are considered promising feed additives , with high potential to improve growth performance and also disease resistance [1] . This paper presents two trials that were conducted to evaluate the effect of a plant extract (curcumin) on the growth performance, immune status and oxidative parameters of Senegalese sole juveniles.
Material and methods
Both trials used two diets: an experimental microdiet , with inclusion of curcumin extract (CC) and a commercial microdiet (WINFlat , Sparos), as Control. Automatic feeders were used to continuously supply inert diets throughout both experiments. In the first trial , microdiets were introduced in the feeding regime of Senegalese sole postlarvae at 3 0 days after hatching (DAH) and kept during 4 weeks (64 DAH). Sole postlarvae were reared at an initial density of 3000 fish/m² in triplicate flat-bottom tanks (8 L), set in a partially-closed recirculating aquaculture system. Sole were sampled at 30 DAH, 50 DAH and 64 DAH. In the second study, sole postlarvae were reared for 25 days, starting at 45 DAH. Sole postlarvae were kept in triplicate flat-bottom tanks (21 L) at a density of 3000 fish/m² and were sampled at 45 and 70 DAH.
Results
At the end of both trials, growth performance was improved in the groups fed CC diets. Senegalese sole fed on diets with curcumin extract presented higher (P<0.05 ) dry weight (T rial 1) and standard length (T rial 2) (P<0.05) when compared to sole fed the control diets (Fig. 1).
Discussion and Conclusion
There is a growing interest in testing new feed ingredients and additives which can promote growth, and improve oxidative status and immune function in early stages of Senegalese sole and other fish species . Plant extracts such as curcumin contain phenolic compounds associated with high antioxidant capacity [2] hence posing high potential to be included as additives in fish feeds. The present results show that diets supplemented with curcumin extracts (CC) promote growth and improve oxidative status in sole postlarvae [4] . P revious studies showed that diet inclusion of curcumin improve sole growth performance through modulation in the expression of genes related to muscle growth [3]. Moreover , curcumin supplemented diets are also linked to improved growth performances and antioxidant activity in other fish species such as tilapia and trout juveniles [4, 5]. Overall results suggest that curcumin extracts at the tested levels are a viable growth promoter and can also contribute to improve oxidative status in early juveniles of Senegalese sole.
Acknowledgements
This work was funded by the Projects PATHAA, and UIDB/04326/2020 from the Foundation for Science and Technology of Portugal (FCT), and by project VALORMAR (ref. 024517) through Compete 2020, Lisboa 2020, CRESC Algarve 2020, Portugal 2020. Maria J. Xavier was supported by Grant PDE/0023/2013 (SANFEED Doctoral program, with support by FCT and SPAROS Lda ., Portugal).
References
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