Miswak (Salvadora persica) modulated the growth performance, antioxidative response, and histopathological damage induced by zinc toxicity in Nile tilapia (Oreochromis niloticus).

In this study, Nile tilapia fingerlings with average body weight (8.6 ± 0.06 g) were exposed to zinc (Zn) toxicity and tested its amelioration with miswak (Salvadora persica L.) (SP) supplemented diet. Five fish groups were fed on diets with SP at 0, 0.25, 0.5, 1.0, and 2.0% (T1, T2, T3, T4, and T5, respectively) diet without Zn exposure, while another five groups were exposed to Zn at 7 mg/L and co-supplemented with SP at 0, 0.25, 0.5, 1.0, and 2.0 % (T6, T7, T8, T9, and T10, respectively). After 12 weeks, fish-fed 1.0% SP diet (T4) achieved the highest growth and feed performances, while the lowest one was in Zn-exposed fish (T6) (P < 0.05). T6 and T7 groups showed the most inferior carcass protein and ash contents, while T4 and T5 showed the highest lipid content (P < 0.05). The level of Zn residue increased in fish exposed to Zn (P < 0.05). Fish exposed to Zn and fed SP showed high blood urea, catalase, ALT, AST, and total superoxide dismutase (T-SOD), while the malondialdehyde (MDA) was decreased (P < 0.05). Interestingly, miswak resulted in elevated catalase and T-SOD and reduced MDA in fish without Zn exposure (P < 0.05). Zn exposure causes abnormal histopathological characteristics in gills, hepatopancreas, posterior kidney, and musculature tissues of tilapia, while fish-fed SP showed regular, healthy, and protected histopathological characters. The results suggested that SP can induce the antioxidant responses that prepare Nile tilapia for a further suppressive oxidative condition (i.e., Zn exposure).

Ziziphus mauritiana supplementation of Nile tilapia (Oreochromis niloticus) diet for improvement of immune response to Aeromonas hydrophila infection.

This study evaluated the effectiveness of dietary Ziziphus mauritiana leaf powder (ZLP) to control Aeromonas hydrophila infection in Nile tilapia and reduce damage to vital immune organs. Four experimental groups were fed a diet supplemented with ZLP at concentrations of 0, 5, 10, and 20 g/kg (w/w) for 6 weeks. At the end of the feeding trial, all groups were intraperitoneally injected with pathogenic A. hydrophila. It was found that Z. mauritiana significantly (P < 0.05) upregulated (lysozyme, interleukin 1 beta) and superoxide dismutase gene expressions as well as improved the activity of serum lysozyme and liver antioxidant enzymes. The fish that were fed a ZLP-supplemented diet also exhibited significantly higher survival rates after A. hydrophila challenge than those that were fed a ZLP-free diet (P < 0.05). Supplementation of 10 g/kg ZLP most effectively reduced the histopathological alterations caused by A. hydrophila challenge in the liver, spleen, kidney, and muscle of the fish. In conclusion, ZLP can be effective in controlling A. hydrophila infection in Nile tilapia (particularly at a concentration of 10 g/kg) through enhancement of its immune and antioxidant status.

Antioxidative and immunostimulatory effect of dietary cinnamon nanoparticles on the performance of Nile tilapia, Oreochromis niloticus (L.) and its susceptibility to hypoxia stress and Aeromonas hydrophila infection.

An experiment was conducted to evaluate the effect of dietary cinnamon nanoparticles (CNP) on the growth performance, antioxidant and digestive enzymes activities, and innate immunity of Nile tilapia, Oreochromis niloticus (L.). Fish (9.7 ±â€¯0.3 g) were fed on diets enriched with 0.0, 0.25, 0.5, 1.0, 3.0, 5.0, and 10.0 g CNP/kg diet for 8 weeks. After the feeding trial, fish were challenged against hypoxia stress or pathogenic bacteria (Aeromonas hydrophila) infection. Fish performance was significantly improved with increasing CNP levels over the control diet. Furthermore, only crude protein contents in whole-fish body were significantly higher in CNP-fed fish than those fed the control diet. Antioxidant-stimulated activity was observed with dietary CNP where malondialdehyde (MDA) level and activities of superoxide dismutase (SOD) and catalase (CAT) increased significantly, whereas glutathione peroxidase (GPx) activity decreased significantly in CNP-fed fish. Likewise, CNP supplementation induced the secretion of protease, lipase, and amylase, which were maximized at 3.0-10.0 g CNP/kg diet. All innate immunity variables i.e. nitrous oxide (NO), nitro blue tetrazolium (NBT), and lysozyme activity were significantly higher in CNP-fed fish than the control one. No fish mortality was observed during hypoxia stress among all treatments, but CNP administration protected the fish against A. hydrophila infection. No mortality was observed in fish fed 3.0-10.0 g CNP/kg diet after bacterial challenge; meanwhile the mortality of fish fed the control diet was 66.7%. This study evoked that dietary CNP enhanced the performance, antioxidant and digestive enzymes activity, and innate immunity of Nile tilapia and its optimum level is 3.0 g CNP/kg diet.