Optimizing nutrient utilization, hydraulic loading rate, and feed conversion ratios through freshwater IMTA-aquaponic and hydroponic systems as an environmentally sustainable aquaculture concept.

Water quality in land-based fish production can be controlled through either instantaneous water exchange or costly wastewater treatment followed by recirculation. Agricultural-aquaculture integration is an excellent alternative technique for reducing nutrient discharge levels, boosting profitability, and converting fish culture wastewater into valuable products. The current study employed a solar energy system to power two separate IMTA-aquaponics systems (Nutrient Film Technique, NFT, and Floating Raft Systems, FRS) for the cultivation of Nile tilapia, African catfish, thin-lipped grey mullet, freshwater crayfish, freshwater mussels, and a variety of vegetables. Tilapia and catfish were fed exclusively on diets under the IMTA system. All wastewater from tilapia and catfish ponds, both dissolved and solid, flows sequentially to ponds containing other cultivated species. The water then flows through the IMTA system's terminal point to the NFT and FRS systems before returning to the tilapia and catfish ponds, allowing complete control of the nutrient flow throughout this entire circular system. Two 147-day production cycles were concluded. The results from the second production cycle are reported. Total biomass gain for aquatic species in the IMTA system was 736.46 kg, compared to 145.49 kg in the tilapia and 271.01 kg in the catfish monoculture systems. The current IMTA system had a cumulative feed conversion ratio (FCR) of 0.90, while the FCRs for tilapia and catfish were 1.28 and 1.42, respectively. Nile tilapia and catfish consumed 571.90 kg of feed containing 25.70 kg of nitrogen (N) and 9.70 kg of phosphorus (P), reflecting, and gaining 11.41 and 3.93 kg of dietary N and P, representing 44.40 and 40.46% dietary N and P retention, respectively. In the IMTA system, the addition of mullet and prawn as detrivores aquatic animals improves dietary N and P utilization efficiency to 59.06 and 51.19%, respectively, while the addition of mussels as herbivore animals improves dietary N and P utilization efficiency to 65.61 and 54.67%, respectively. Finally, using FRS and NFT as hydroponic systems increased dietary N and P efficiency to 83.51% N and 96.82% P, respectively. This study shows that the IMTA-Aquaponic system, as a bio-integrated food production system, can convert the majority of fish-fed residues into valuable products suitable for desert, rural, and urban areas in impoverished and developing countries.

Nano Iron Versus Bulk Iron Forms as Functional Feed Additives: Growth, Body Indices, Hematological Assay, Plasma Metabolites, Immune, Anti-oxidative Ability, and Intestinal Morphometric Measurements of Nile tilapia, Oreochromis niloticus.

The current study aimed to compare the utilization efficiency of iron (Fe) feed additives from either bulk or nano sources in Nile tilapia, Oreochromis niloticus diets on growth, haematological, immunity, anti-oxidative, and intestinal topography capacities. Five isonitrogenous and isoenergetic diets were performed; the basal diet served as a control with no Fe added, whereas the experimental diets were shaped by adding bulk-Fe2O3 and nano-Fe2O3 to the basal diet to preserve Fe levels at 0.2 and 0.4 mg kg-1, respectively. Results indicated that superior growth performance was recorded in fish-fed diets supplemented with 0.4 nano-Fe2O3 mg kg-1 diet. In addition, the highest (P ≤ 0.05) survival rate, absorption area of villous (AAV), mucosal to serosal amplification ratio (MSR), and villi parameters (height and width) were noticed in fish fed diet enrichment with either bulk or nano-Fe2O3 source. However, the superiority observed in nano-Fe2O3 fish groups. Also, the highest values of plasma albumin, total protein, high-density lipoprotein cholesterol (HDL-C), white blood cells (WBCs), and lymphocyte absolute count (LYM) (P ≤ 0.05) recorded in fish fed a diet supplemented with nano-Fe2O3 versus the basal diet. Moreover, the highest values of catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD), and plasma lysozyme activity (P ≤ 0.05) were observed in fish fed 0.4 mg/kg-1 nano-Fe2O3, while the lowest value was recorded in fish fed the control diet. The best value of malondialdehyde activity (P ≤ 0.05) recorded in a fish-fed diet supplemented with 0.4 mg/kg-1 nano-Fe2O3. The current findings emphasize the importance of including Fe to improve fish growth, immunity, antioxidant capabilities, and intestinal structure, primarily with a nano-Fe source, which demonstrated a more effective function in satisfying Nile tilapia dietary Fe requirements and improving the aforementioned parameters.

Evaluation of Different Copper Sources in Nile Tilapia Diets: Growth, Body Indices, Hematological Assay, Plasma Metabolites, Immune, Anti-Oxidative Ability, and Intestinal Morphometric Measurements.

The goal of the current study was to compare how well Nile tilapia, Oreochromis niloticus, utilized copper (Cu) as bulk and nano sources by evaluating fish growth, body indices, hematological assays, plasma metabolites, immune and anti-oxidative abilities, and intestinal morphometric measurements. The basal diet served as a control, with no Cu added, whereas the experimental diets were formed by adding bulk-Cu and nano-Cu to the basal diet to keep Cu levels at 3 and 6 mg kg-1, respectively, in both Cu sources. Tilapia (9.10 ± 0.014 g) were fed the control diet and four experimental diets for 12 weeks. Results indicated that growth, feed utilization, and body indices demonstrated a substantial improvement (P ≤ 0.05) in tilapia that received a diet containing 3 and 6 Nano-Cu mg kg-1 diet, compared to the performance of fish that received diets containing 3 and 6 Bulk-Cu mg kg-1 diet and the control diet. Villi height, villi width, absorption area of villous (AAV), and mucosal to serosal amplification ratio (MSR) values demonstrated a substantial increase (P ≤ 0.05) in tilapia fed 3 and 6 mg kg-1 Nano-Cu compared to the values observed in fish fed the control and Bulk-Cu supplemented diets. Fish fed Bulk-Cu recorded the highest (P ≤ 0.05) hemoglobin concentration in those fed 6 mg kg-1 compared to 3 mg kg-1. Hematocrit value considerably improved (P ≤ 0.05) by supplementation of Cu, whereas the highest significant value demonstrated in fish provided 6 mg/kg-1 Nano-Cu. A fish-fed diet containing 3 mg kg-1 Nano-Cu revealed the best (P ≤ 0.05) values of plasma albumin, total protein, and globulins. Plasma HDL-C highest concentrations (P ≤ 0.05) were reported in fish fed diet supplemented with 6 mg/kg-1 either Bulk or Nano Cu, whereas values of plasma TG and VLDL-C declined as Cu supplementation level increased either from Bulk or Nano source. Also, the best (P ≤ 0.05) values of CAT and GPX were seen in fish given diet supplemented with 6 Nano-Cu mg/kg-1. Fillets of fish-fed Nano-Cu-supplemented diets showed a marked decline (P ≤ 0.05) in moisture and fat contents, while crude protein, ash, and Cu contents considerably increased in the fillet by dietary supplementation of Nano-Cu at both levels 3 and 6 mg kg-1. In conclusion, the supplemental diets with 3 or 6 Nano-Cu mg/kg-1 enhanced growth, feed utilization, body indices, fillet nutrient composition, hematological assay, plasma metabolites, immune, antioxidant activities, and intestinal morphometry of Nile tilapia.

Comparative study on the effect of dietary ß-carotene and phycocyanin extracted from Spirulina platensis on immune-oxidative stress biomarkers, genes expression and intestinal enzymes, serum biochemical in Nile tilapia, Oreochromis niloticus.

The current trial investigated the roles of ß-carotene and phycocyanin extracted from Spirulina platensis on growth, serum biochemical, digestive enzymes, antioxidant defense, immune responses, and immune gene expression in Nile tilapia (Oreochromis niloticus). Fish (1.52 ± 0.10 g) were randomly stocked to three treatments with three replicates (12 fish per replicate) in nine aquaria (60 L glass aquarium for each), and reared for 70-days. Three tested diets were formulated to be isonitrogenous and isolipidic, and were offered for experimental fish until ad-libitum three times daily at 09:00 a.m., 11.00 a.m. and 3:00 p.m. The first diet (control) was without supplementation. About 50 mg ß-carotene and 50 mg phycocyanin kg-1 were supplemented to the other experimental diets, respectively. Results indicated that feed intake was not (P > 0.05) differ among experimental diets. Compared to control diet wight gain and specific growth rate were significantly (P < 0.05) in fish fed diet containing ß-carotene, while, the highest weight gain and the best FCR were detected in phycocyanin diet. Survival fish among treatments was significantly (P < 0.05) differ and the highest survival rate was showed in fish fed diet supplemented with phycocyanin. Either ß-carotene or phycocyanin significantly (P < 0.05) improved the intestinal digestive enzymes compared with control diet, where the highest values of chymotrypsin, trypsin, lipase and amylase were noticed in fish fed phycocyanin. Diets supplemented with ß-carotene and phycocyanin significantly (P < 0.05) improved hematology parameters contents compared with to the control diet, and the best contents were detected in fish fed diet supplemented with phycocyanin. The highest significant (P < 0.05) phagocytic, lysozyme, immunoglobulin M (IgM), superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx) and total antioxidant capacity (T-AOC) activities were recorded in diet supplemented with phycocyanin. The transcripts of interferon gamma and interleukin 1ß genes were (P < 0.05) up-regulated in the liver of fish fed diet supplemented with ß-carotene and phycocyanin, but expression of HSP70 gene down-regulated in fish fed ß-carotene and phycocyanin containing diet compared control. The highest gene expression of the interferon gamma and interleukin 1ß was observed in fish fed phycocyanin.