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The present study evaluated the impacts of powdered Astragalus membranaceus extract (AME) on the growth, physiological responses, and serum immunity of Pangasianodon hypophthalmus juveniles. Four test diets were formulated to include varying AME levels as 0.0 (control), 1.5 (AME1.5), 3.0 (AME3.0), and 4.5 (AME4.5) g/kg. Fish weighing approximately 11.50 g were stocked into four triplicate groups and hand-fed on the test diets three times daily for two months. At 60 days post-feeding, the growth performance, including weight gain and the specific growth rate, was increased quadratically (R2 > 0.90) with increasing AME inclusion levels. An improvement in the feed intake and feed conversion ratio were also noticed in groups fed at different AME levels. The whole-body and amino acid composition were unaffected by the test diets. A significant quadratic trend in the digestive enzymes (lipase, α-amylase, and protease) was found along with increasing AME inclusion levels. Liver enzymes associated with liver functions were improved by AME dietary inclusion levels. Meanwhile, the blood urea nitrogen, uric acid, and creatinine values were unaffected by AME dietary inclusion. On the other hand, serum immunity (lysozyme and total Igs) was elevated with a significant quadratic trend along with increasing AME dietary inclusion levels. Liver MDA levels decreased with increasing AME levels. Liver CAT, GPx, and SOD enzyme activities demonstrated a significant increasing trend along with dietary AME inclusion. The aforementioned effects of dietary AME on P. hypophthalmus health underpinned the potentiality of AME to be used as a phyto-additive to improve the functionality of aquafeed.

In the present study, fish were exposed to sub-lethal doses of CuONPs (68.92 ± 3.49 nm) (10 mg/L, 20 mg/L, and 50 mg/L) for a long exposure period (25 days). Compared to the control group (0.0 mg/L CuONPs), a significant dose-dependent elevation in blood urea and creatinine values, serum alanine transaminase, aspartate transaminase, and alkaline phosphatase enzyme activities were evident in CuONPs-exposed groups (p < 0.05). Fish exposure to 50 mg/L CuONPs significantly upregulated the transcription of pro-inflammatory cytokines (tumor necrosis factor-alpha, interleukin-1beta, interleukin 12, and interleukin 8), heat shock protein 70, apoptosis-related gene (caspase 3), and oxidative stress-related (superoxide dismutase, catalase, and glutathione peroxidase) genes in liver and gills of the exposed fish in comparison with those in the control group (p < 0.05). Moreover, varying histopathological injuries were noticed in the hepatopancreatic tissues, posterior kidneys, and gills of fish groups correlated to the tested exposure dose of CuONPs. In summary, our results provide new insights and helpful information for better understanding the mechanisms of CuONPs toxicity in Nile tilapia at hematological, molecular levels, and tissue levels.

The current investigation assessed the impacts of sub-lethal concentrations of silicon dioxide nanoparticles (SiO2NPs) on hepato-renal functions, histopathological characteristics, and gene transcription in gills and liver of Nile tilapia juveniles. Fish were exposed to 20, 40, and 100 mg/L of SiO2NPs for 3 weeks. Pairwise comparisons with the control group showed a significant dose-dependent elevation in serum ALP, ALT, and AST enzyme activities as well as blood urea and creatinine levels in SiO2NP-intoxicated groups. Exposure to 100 mg/L SiO2NPs significantly upregulated expression of HSP70, TNF-α, IL-1β, and IL-8 genes in the gills as compared to the control group. Moreover, exposure to 100 mg/L SiO2NPs significantly upregulated the expression SOD, HSP70, IL-1β, IL-8, and TNF-α genes in the hepatic tissues as compared to the control group. Exposure of fish to 20 mg SiO2NPs/L significantly increased the mRNA expression levels of IL-12 in both the gills and liver tissues. Notably, all tested SiO2NP concentrations significantly upregulated the transcription of CASP3 gene in gills and liver of Nile tilapia as compared to the control group. Interestingly, varying histopathological alterations in renal, hepatopancreatic, and branchial tissues were observed to be correlated to the tested SiO2NP concentrations. In conclusion, our results provide additional information on the toxic impacts of SiO2NPs in Nile tilapia at the hematological, tissue, and molecular levels.