Introduction
Asian seabass, Lates calcarifer is a well-known farmed species with an established market. It is a warm water carnivorous, fast growing euryhaline fish (Schipp et al, 2007). These biological traits together with its consumer acceptance points to the potential for expansion of barramundi farming worldwide (Lawley, 2010). The cultivation of this species in RAS (recirculating aquaculture system) needs further development (Larkin, 2000) and the present study compare the growth performances and morphological – body quality traits of Asian seabass at two different salinity levels, testing also a microalgae extract (Nannochloropsis gaditana) for potential benefits to fish growth, health, and fillet traits (Nagappan et al, 2021).
Material and methods
Asian seabass, Lates calcarifer (50 fish/tank; initial weight of 64.9 ± 0.1g) reared at two different salinities, 38+/-2ppm (S1) and 14 +/- 2ppm (S2) in RAS. Fish in both systems were fed four times daily to satiation with either a control diet (CTRL) or the CTRL diet supplemented with N. gaditana liquid extract top coated at 3% (W/V) (ALG). After the 10 week trial period, a bulk sample weight of all tanks was performed and 8 fish from each tank were sampled to carry out carcass analysis, obtain biometric-morphometric data, as record body quality traits.
Results
At the end of feeding trial, no significant differences were found in the average final weight and SGR among the different treatments. Both treatments reared in S1 had significantly higher FCRs than the FCRs of both treatments reared in S2, compared whilst feed intake of fish in S2 were significantly higher than that of fish fed CTRL (S2)
Although numerical differences were apparent, all biometric, morphometric indexes and fillet yield and quality parameters except VSI were found not to be statistically different between treatments. VSI was significantly higher in fish from S1 compared to S2. Results of body colour intensity (L*, a* and b* coordinate) using a Minolta Chroma-Meters CR-400 cat. 1878-209 showed no significant difference between S1 and S2 in both treatments.
References
Larkin, B. (2000). Recirculating aquaculture systems in Australia: a synthesis of systems, species and the networking approach. In Proceedings of the 3rd International Conference on Recirculating Aquaculture, Roanoke, VA (USA) 20-23 Jul 2000.
Lawley, D. B. (2010). Repositioning Australian farmed barramundi: Online consumer survey findings. University of Sunshine Coast, Sunshine Coast, QLd.
Nagappan, S., Das, P., AbdulQuadir, M., Thaher, M., Khan, S., Mahata, C., ... & Kumar, G. (2021). Potential of microalgae as a sustainable feed ingredient for aquaculture. Journal of Biotechnology, 341, 1-20.
Schipp, G., Bosmans, J., & Humphrey, J. (2007). Barramundi farming handbook. Department of Primary Industry, Fisheries and Mines, Northern Territory Government, 1-81.
Acknowledgement
This research was conducted under the iFishIENCi H2020 project. The iFishIENCi project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 818036.