Mannanoligosaccharides as a Carbon Source in Biofloc Boost Dietary Plant Protein and Water Quality, Growth, Immunity and Aeromonas hydrophila Resistance in Nile Tilapia (Oreochromis niloticus).

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 (O. niloticus) juveniles. Fish (n = 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 Bacillus spp. count was increased, whereas Vibrio, Aeromonas and Pseudomonas 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 Aeromonas hydrophila 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.

Effect of Chlorella vulgaris enriched diet on growth performance, hemato-immunological responses, antioxidant and transcriptomics profile disorders caused by deltamethrin toxicity in Nile tilapia (Oreochromis niloticus).

The toxic effect of deltamethrin (DM) was documented in aquaculture. There is no obtainable data on the effect of Chlorella vulgaris against DM toxicity. The current study focused on the effect of dietary supplementation with C. vulgaris (CV) on growth performance, innate immune response, antioxidant activities, and transcriptomics disorders induced by sub-lethal dose of DM in Oreochromis niloticus. A total number of 216 O. niloticus divided into four groups with tri-replicates. The 1st control group (CT) fed a basal diet, the second group fed diet enriched with 5% CV. The third group was exposed to DM (15 µg/L), where the last group fed CV and simultaneously exposed to DM as previous-mentioned. The procedure of CV feeding and DM exposure were continued for two months. Exposures to DM revealed in stunting of the growth parameters and lessening of survival ratio of tilapias with a significant decline of the erythrogram (macrocytic hypochromic anemic picture), and leucocytes immune cells and related parameters (immunoglobulin M, lysozyme) and sever shifting in the antioxidant indicators. Sever raise was monitored in hepatic and kidney markers. Also, genes expression related to immune and antioxidant parameters were severely impacted. Where tilapias received CV showed a significant increase in the growth and immune parameters besides to an improvement of hematological, antioxidant values and their related genes expressions. The fourth group that received CV simultaneous with DM exposure showed a soothing of the previous indicators and markers toward the values of tilapias fed on basal diet (CT). In turn, CV supplementation may be presented a protective effect alongside DM toxicity in O. niloticus appeared through soothing of the immune, antioxidant and related genes expressions in addition to its hepato-renal protective effects. Therefore, the current study recommended that an incorporating of 5% CV for tilapias diet could improve their growth performance, immunity, antioxidant and transcriptomics disorders induced by deltamethrin.

Immune-protective, antioxidant and relative genes expression impacts of ß-glucan against fipronil toxicity in Nile tilapia, Oreochromis niloticus.

Our study is considered to attempt reducing the immune-toxic and antioxidant impacts of exposure to fipronil (FP) on Nile tilapia, Oreochromis niloticus using the ß-glucan (ßG). Two hundred and seventy fingerlings of Nile tilapia were divided randomly into six groups (45 tilapias of each, in 3 replicates): group I control (CT) group nourished on a basal diet. Group II (ßG) nourished a basal diet supplemented with 0.4% ßG. Groups III (1/20 FP) and V (1/10 FP) was exposed to 1/20 and 1/10 of the 96 h LC50 of FP in water and nourished the basal diet respectively. Groups IV (1/20 FP+ ßG) and VI (1/10 FP+ ßG) were exposed to 1/20 and 1/10 FP concomitantly with 0.4% ßG supplementation for 90 successive days. Growth performance metrics were higher in ßG group than CT. While those metrics were fallen at exposure to 1/20 or 1/10 FP. Supplementation with ßG elevated the IgM and lysozyme levels.Whereas, tilapias exposed to FP only at different concentration showed lowering of those compared to CT. Supplementation with ßG was effectively augmented IgM and lysozyme in 1/20 FP exposed tilapias. Furthermore, in a minor grade at 1/10 FP exposed tilapias. Exposure to FP increased the activities of hepatic markers chiefly at 1/10, however the ßG supplementation was successfully improved these markers. There was imbalance of cortisol level at FP exposure where, ßG combining to FP alleviate this disparity. There was fallen in LDH, MDH and FDPase in ßG tilapias where continuing raise in 1/10 FP followed by 1/20 FP. ßG supplementation raise the level of GSH, without significant variations in MDA conversely occurs in FP alone. Genes expression of ßG caused raise of both GPx and GR, without fluctuations in CAT and SOD. Exposure to FP diminishes all evaluated antioxidant genes. It could fulfilled that supplementation with ßG successfully alleviated the immune-toxic and antioxidant impact of FP in tilapias.