Mannanoligosaccharides as a Carbon Source in Biofloc Boost Dietary Plant Protein and Water Quality, Growth, Immunity and <i>Aeromonas hydrophila</i> Resistance in Nile Tilapia (<i>Oreochromis niloticus</i>)
oleh: Asmaa T.Y. Kishawy, Alaa H. Sewid, Hend S. Nada, Mohamed A. Kamel, Shefaa A.M. El-Mandrawy, Taghrid M.N. Abdelhakim, Abd Elhakeem I. El-Murr, Nihal El Nahhas, Wael N. Hozzein, Doaa Ibrahim
| Format: | Article |
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| Diterbitkan: | MDPI AG 2020-09-01 |
Deskripsi
The aim of the present study was to evaluate mannan oligosaccharides (MOS) or glycerol (GLY) as a carbon source on biofloc systems of Nile tilapia (<i>O. niloticus)</i> juveniles. Fish (<i>n</i> = 750) were reared in open flow (Controls) or biofloc systems (B-GLY and B-MOS) fed with a plant or fish protein source over a period of twelve weeks. Total ammonia nitrogen and nitrate decreased in the biofloc groups, while biofloc volume increased in B-MOS. Compared to the controls, B-MOS and B-GLY exhibited higher weight gain and improved feed conversion, irrespectively of the diet. Serum level of C-reactive protein was reduced, while IgM and lysozyme activity was higher in the B-MOS fish, compared to other groups. Intestinal <i>Bacillus</i> spp. count was increased, whereas <i>Vibrio, Aeromonas</i> and <i>Pseudomonas</i> spp. counts decreased in B-MOS reared groups, compared to the other groups. The proinflammatory cytokine (IL-8 and IFN-γ) transcript expression was upregulated in B-MOS more than B-GLY reared groups. Compared to the controls, the virulence of <i>Aeromonas hydrophila</i> was decreased in the B-MOS and B-GLY groups. The results indicate several benefits of using MOS as a carbon source in a biofloc Nile tilapia system; a cost benefit analysis is required to assess the economic viability of this.