Effects of flow rate on growth performance and welfare of juvenile turbot (Scophthalmus maximus L.) in recirculating aquaculture systems |
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| Authors: | Guoxiang Sun Meng Li Jie Wang Ying Liu |
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| Affiliation: | 1. Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China;2. University of Chinese Academy of Sciences, Beijing, China;3. National and Local Joint Engineering Laboratory of Ecological Mariculture, Qingdao, China;4. Ocean University of China, Qingdao, China;5. Qingdao Technology University, Qingdao, China |
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| Abstract: | The effects of flow rate on growth and welfare of juvenile turbot (Scophthalmus maximus L.) were investigated in the present study. Fish with same initial weight (102.5 ± 10.6 g) were subjected to four flow rates, equalling to 0.5, 1, 1.5 and 2 tank volumes per hour in twelve 392 L tanks during 80 days. Results showed that specific growth rate of turbots increased (0.40–0.58% day?1) significantly with promoted flow rate (P < 0.05). Total ammonia nitrogen, nitrite nitrogen, unionized ammonia nitrogen, chemical oxygen demand, total bacteria and total vibrio in tanks were affected significantly by flow rate and accumulations were found in low rate (200 L h?1) (P < 0.05). Free carbon dioxide increased significantly with the increased flow rate and ranged between 4.5 and 13.5 mg L?1 (P < 0.05). Both superoxide dismutase activity and lysozyme activity increased significantly with flow rate (P < 0.05), with ranges of 108.51–131.57 U mL?1 and 551.81–869.28 U mL?1. Serum cortisol showed reversed tendency and ranged between 7.39–19.26 ng mL?1. The principal components analysis suggested that increased flow rate promoted fish welfare. It was concluded that increased flow rate promoted the growth of juvenile turbot, possibly explained by fish welfare differences in combination of health, water quality and serum parameters. |
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| Keywords: | Scophthalmus maximus L flow rate growth water quality welfare recirculating aquaculture systems |
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