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Supplementation of phosphorus nanoparticles is a promising strategy to reduce water pollution, improve phosphorus concentration in fish diet, and provide better production quality. We used 300 fingerlings of Nile tilapia that were randomly distributed into 3 groups; each one was attributed to 5 replicates of 20 fish per aquarium with initial weight (gm) (156 ± 1.25). The first diet contained traditional Di-calcium phosphate (D-group), the second supplemented with phosphorus nanoparticles in a dose equal to the previous conventional one (N-D group), and the last one included with phosphorus nanoparticles with the half dose of the conventional phosphorus group (1/2 N-D group). After 3 months of feeding, the N-D group showed the best growth performance including its feed conversion ratio (FCR), feed intake (FI), or body weight gain (BWG). Furthermore, the growth-related gene expression findings considering growth hormone receptor (GHR) and insulin-like growth factor-1 (IGF-1) were upregulated as well. Moreover, whole body chemical composition revealed higher Fe, Zn, P, and crude protein level in the N-D group than the other two groups. Lipoprotein lipase (LPL) and fatty acid synthetase (FAS) mRNA expression showed a significant increase in 1/2 N-D and N-D groups compared with the control group. To sum up, using of nano-phosphorus particles improved the growth rate and immunity response of Nile tilapia, besides decreasing water pollution.

Fermentation strategy is well documented to improve the nutritional value of agricultural waste by-products such olive cake (OC), which, in turn, provides healthy, safe, and affordable feedstuff. This study assessed the combined impact of Aspergillus oryzae-fermented OC (AFOC) on the growth performance, intestinal morphometry, blood biochemistry, lysozyme activity, gut immune-related genes, and flesh quality of Nile tilapia. We divided 225 fish into five groups and further subdivided into three replicates (n = 15 each) and fed them five diets (Control, AFOC5, AFOC10, AFOC15, AFOC20) to determine AFOC nutritional value and its optimized incorporation level in the diet. The trial continued for 3 months. The crude protein content of OC improved by 7.77% after A. oryzae fermentation, while lipid content decreased by 14.19%. In addition, growth and feed utilization significantly improved at (10.8–11.2) % AFOC dietary level. High-density lipoprotein (HDL) significantly improved, and the serum lysozyme level was significantly higher in the AFOC10 group compared to other groups. Interestingly, gut-related inflammatory cytokines tumor necrosis factor alpha (TNF- α) and interleukin 1 beta (IL-1β) revealed higher relative mRNA expression in the AFOC10 group compared to other groups. The histomorphometric parameters was greatly influenced by the AFOC incorporation level (10%–20%). These findings suggested that A. orzae fermentation modifies the nutritional quality of OC, as seen through its positive impact on the growth performance, local and systemic immunity, and intestinal absorptive capacity of Nile tilapia. The recommended dose for dietary AFOC was around 11%

A 95-day feeding trial was conducted to evaluate the outcomes of feeding Bacillus subtilis fermented Azolla (BSFA) on nonspecific immunity, antioxidative status, intestinal digestive enzymes and histomorphometry, and disease resistance in the Nile tilapia. We formulated five isonitrogenous and isocaloric experimental diets to incorporate BSFA at level of (0%, 15%, 30%, 45%, 60%). The growth performance parameters (FBW, BWG, SGR, PER, and FCR) revealed a significant increase in the BSFA30 tilapia group compared to the control group followed by BSFA45 (P < 0.05). The BSFA30 group exhibited the highest nonspecific immunity parameters including (lysozyme activity, phagocytic index, and phagocytic activity) compared to other groups (P < 0.05). SOD and GPx reported the highest values in the BSFA60 group. Nile tilapia carcass composition was not influenced by BSFA inclusion level (P > 0.05). Interestingly, Nile tilapia fed with BSFA15 diet exhibited the highest protease activity level (P < 0.05), while those fed on BSFA30 documented the highest amylase activity. Intestinal histomorphology was significantly enhanced with the gradual increase of administrated BSFA. Regarding the tilapia disease resistance against Aeromonas septicemia, BSFA significantly diminished the cumulative mortality compared to the control group. To sum up, BSFA was more effective in improving the growth performance and immunity of Nile tilapia. Graphical abstract

This study investigates the effects of different sources of selenium (inorganic (SSE), organic (OSE), and elemental nano-selenium (NSE)) on the performance of Nile tilapia (Oreochromis niloticus). In total, 204 Nile tilapia fingerlings were randomly divided into 4 equal groups fed 1 of 4 diets: a control (adding no selenium) and 3 diets as selenium sources (1 mg/kg diet), After a 65-day feeding trial, the growth performance parameters of Nile tilapia were significantly enhanced by dietary selenium supplementation (P 0.05), with the highest values recorded in the OSE- and NSE-supplemented groups. The selenium-supplemented groups had the highest packed-cell volume, hemoglobin, and red blood cell levels, with the highest values seen in the NSE-supplemented group (P 0.05). Innate immune-related enzymes and immunoglobulin levels were significantly enhanced with selenium supplementation (P 0.05); the NSE group demonstrated the highest significant levels of these enzyme activities (P 0.05). In all selenium-supplemented groups, malondialdehyde levels were significantly and equally reduced (P 0.05) compared with levels in the control. Bactericidal activity was only enhanced in the NSE group (P 0.05) compared with other treatments. The expression of TNF-α and IL-Iβ genes was significantly upregulated in selenium-supplemented groups, with the highest expression in the OSE and NSE groups (P 0.05). These findings support the importance of incorporating selenium in the diet of Nile tilapia. Furthermore, elementary nano-selenium is more effective than inorganic or organic selenium supplementation at improving Nile tilapia growth performance and overall health.