Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8498174 | Fish & Shellfish Immunology | 2018 | 36 Pages |
Abstract
A 120-day feeding trial was conducted to evaluate the effect of different stocking densities on growth, the non-specific immunities, antioxidant status and digestive enzyme activities of Oreochromis niloticus fingerlings under a zero-water exchange biofloc system. Tilapias (0.51â¯Â±â¯0.05â¯g) were randomly distributed in twelve tanks, each with 300â¯L water. The experimental design was completely randomized using three replications with four treatments 166 orgs mâ3 (LD, low density), 333 orgs mâ3 (MD, middle density) and 600 orgs mâ3 (HD, high density) with glucose added as biofloc groups, and a clear water group without glucose added as a control 333 orgs mâ3. The fish cultured in LD and MD group showed higher final body weight. For the digestive enzymes, the lipase, trypsin, and amylase activities were all depressed in HD group and control group. Regarding the immune and antioxidant abilities, significantly lower values (Pâ¯<â¯0.05) of the lysozyme, complement 3, and glutathione were observed for the fish that reared in the control group and HD group. The stress indicator, the cortisol, 5-hydroxytryptamine, and glucose concentrations were also depressed in HD group and control group, meanwhile the alanine aminotransferase, aspartate transaminase and alkaline phosphatase were all higher in HD group and control group. The significant higher survival was observed in the LD and MD group after Vibrio harveyi challenge test. The results of the experiment indicated that the biofloc in situ had the effects of anti-crowding stress.
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Authors
Gang Liu, Zhangying Ye, Dezhao Liu, Jian Zhao, Elayaraja Sivaramasamy, Yale Deng, Songming Zhu,