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In aquaculture feed accounts for more than 50% of current costs. Biofloc has the potential to compensate for food reduction, so restricted feeding levels should be investigated to decrease food consumption. The present study conducted to evaluate the effect of restricted feeding levels and stocking densities on water quality, growth performance, body composition and mucosal innate immunity of Nile tilapia (Oreochromis niloticus) fry in biofloc system (BFT). A 5*2 factorial experimental design was used with five restricted feeding levels (0, 15, 30, 45 and 100) and 2 stocking densities(500 fish/m3 and 1000fish/m3) comprising 10 treatments for BFT and for each density there were clear water (CW) system as control with three replicates. Fry with initial weight of 3.2 ± 0.05 g were stocked in tank(40 L), fed three times a day at 8:00, 12:00 and 16:00. Molasses was added to BFT treatments as organic carbon source at a C/N ratio of 15. Results showed that, growth indices (WG, DGR, SGR, FCR), water quality parameters (TAN, NO2, NO3, settled solids and total suspended solids), as well as innate immunity (Total immunoglobulin, Lysozyme and Catalase activity) were improved in biofloc system compared to the CW system. The reduction of feeding rate resulted in significantly decreasing growth performances and immunity among biofloc groups (p 0.05) except for the non-feeding biofloc treatment with stocking density of 1000/m3 (67/9%). Innate immunity was significantly decreased by reduction of feeding rates while, Liver enzyme activity showed an increasing trend by reduction in feeding rate and increasing the stocking density (p > 0.05). These results indicate that the BFT improved water quality, growth performance and immune function of Nile tilapia fry compared to CW system. Also it is possible to decrease 15% daily feeding rate in BFT system. In conclusion, the study suggests the stocking density of 1000/m3 for larviculture of tilapia in BFT to use water and equipment more efficiently.

Iron and copper are two essential micronutrients that play important roles in vital biological processes, key enzymes and the immune system. In this study, the effects of diet supplementation with inorganic and nanoparticulate iron and copper on growth performance and hemato-immunological responses of snow trout Schizothorax zarudnyi (23.97 ± 0.45 g) were investigated for 84 days. The fish were fed by seven experimental diets supplemented with 0 mg copper and iron (Cu, Fe) (control), 150 mg inorganic iron (FeI), 3 mg inorganic copper (CuI), 150 mg FeI and 3 mg CuI (FeI + CuI), 150 mg nanoparticulate iron (FeNPs), 3 mg nanoparticulate copper (CuNPs), 150 mg FeNPs and 3 mg CuNPs (FeNPs+CuNPs) per kg of diet. The results showed that the diet supplementation with Fe and Cu improved the growth and feeding indices compared with the control treatment; however, the nanoparticulate Fe and Cu acted more effectively than their inorganic counterparts. The values pertaining to the most hematological parameters, such as RBCs, hematocrit and hemoglobin, were higher in nanoparticulate treatments than in the inorganic ones (P

In the present study, we prepared silver nanoparticles immobilized on silica beads (Ag/TEPA-Den-SiO2) and examined their potential for removing luminous Vibrio sp. Persian1 from seawater used to culture Penaeus (Litopenaeus) vannamei post-larvae. The Ag/TEPA-Den-SiO2 sample was characterized by TEM, FE-SEM/EDS, FT-IR and ICP-OES and its antibacterial activity assayed by a test tube test and flow test using water filters filled with Ag/TEPA-Den-SiO2 as the filter media. The results of the test tube test indicated that no Vibrio sp. Persian1 was detectable after 2-h contact. The filter column that contained Ag/TEPA-Den-SiO2 + silver absorbent inactivated 100% of the bacteria after passage of seawater through the column for 12-h at a flow rate of 0.5 l/min. The survival rate and growth performance of post-larvae cultured in seawater treated with an antibacterial filter improved significantly compared with the control.

The synthesis of photocatalysts revealing efficient performance under the visible light has recently broadened its appeal for the removal of environmental pollutants from the water and wastewater. Besides, the biosynthesis of nanostructured photocatalysts with the tunable surface plasmon band is eco-friendly and worth attending. In the same vein, this study was an endeavor to synthesize Ag/AgCl@TiO2 plasmonic photocatalyst, with an enhanced photoactivity under the sunlight by a facile biosynthesis method using aqueous leaf extract of mangrove plant Avicennia marina, as a reducing and stabilizing agent as well as a chlorine source. To this end, the plasmonic Ag/AgCl@TiO2 nanocomposite, with the particle size of ∼35 nm, the specific surface area of 31.94 m2 g−1, and the bandgap energy of 1.73 eV, was successfully synthesized with aqueous leaf extract/AgNO3 (R1) and AgNO3/TiO2 (R2) ratios of 0.31 and 1.61, respectively. Different techniques examined the effect of R1 and R2 on the characteristics of the products. Consequently, the results indicated that Ag/AgCl@TiO2 nanocomposite exhibited a swift degradation of the eosin Y dye in 60 min under the sunlight. A topmost dye photodegradation of 99% was attained at pH 4 with the photocatalyst concentration of 0.05 g/100 mL and the eosin Y concentration of 50 mg/L at the ambient temperature. The surface plasmon resonance and the effective charge separation due to the heterostructure developed among Ag, AgCl, and TiO2 could be accountable for the absorption band expansion to the visible light area and the significant photocatalytic activity of Ag/AgCl@TiO2 under the sunlight. Recycling experiments for the five cycles elucidated the magnificent long-term photocatalytic stability of the biosynthesized Ag/AgCl@TiO2. The operation simplicity and the potential of utilizing the sunlight energy prompted the biosynthesized Ag/AgCl@TiO2 to be a noteworthy reusable candidate for the photodegradation of the toxic organic pollutants in the aqueous solutions.

Zinc as an essential micronutrient in organisms and natural environments plays an important role in many biological activities. In this study, the effects of feeding with different sources of zinc supplements on seminal biochemical and enzymatic changes and quality and quantity indices of sperm in rainbow trout (Oncorhynchus mykiss) were investigated. A total of 108 broodstock males in four treatments were fed diets supplemented with 40 mg kg−1 of: 1. Mineral zinc (ZnSO4), 2. Zinc nanoparticles (ZnO-NPs), 3. Organic zinc (Zn-proteinate, Bioplex Zn®) and 4. A diet containing no extra added zinc as control for 16 weeks. Sperm motility duration and spermatocrit percentage were higher in treatments supplemented with all zinc sources than the control group (P