Glyphosate-induced liver and kidney dysfunction, oxidative stress, immunosuppression in Nile tilapia, but ginger showed a protection role.

The water-borne herbicides are involved in the toxicity of aquatic animals resulting in impaired health status and low productivity. Dietary medicinal herbs present a practical solution to relieve the impacts of herbicides toxicity on the performances of aquatic animals. Herein, we investigated the toxicity of commercial glyphosate-induced oxidative stress, immunosuppression, liver and kidney dysfunction, and the protective role of ginger or ginger nanoparticles in Nile tilapia. Fish were allocated into four groups: the first group presented the control without glyphosate toxicity and ginger feeding, the second group intoxicated with glyphosate at 0.6 mg/L and fed ginger free diet, the third group intoxicated with glyphosate and fed ginger at 2.5 g/kg, and the fourth group intoxicated with glyphosate and fed ginger nanoparticles at 2.5 g/kg. Fish were kept under the experimental conditions for four weeks, and the samples of blood and tissues were collected after 2 and 4 weeks. Markedly, fish exposed to glyphosate showed the highest ALT and AST activities, glucose and cortisol levels, and malondialdehyde levels (MDA) in gills and tissues. While fish in the control and fish intoxicated with glyphosate and fed ginger nanoparticles had the lowest ALT and AST activities, glucose and cortisol levels, and MDA levels after 2 and 4 weeks (P < 0.05). Fish fed dietary ginger had lower ALT and AST activities, glucose and cortisol levels, and MDA levels than the glyphosate intoxicated group after 2 and 4 weeks (P < 0.05). Interestingly, fish-fed ginger nanoparticles showed lower urea and creatinine levels and higher total protein, albumin, and globulin than the glyphosate intoxicated group (P < 0.05) and similar to the control (P > 0.05). Further, fish intoxicated with glyphosate and fed ginger nanoparticles had the highest GSH, lysozyme activity, and immunoglobulin levels after 2 and 4 weeks (P < 0.05). In conclusion, ginger nanoparticles are superior to the standard ginger form in enhancing the antioxidative and immune responses of Nile tilapia exposed to glyphosate.

Potential effects of dietary seaweeds mixture on the growth performance, antioxidant status, immunity response, and resistance of striped catfish (Pangasianodon hypophthalmus) against Aeromonas hydrophila infection.

Striped catfish (Pangasianodon hypophthalmus) is one of the important fish species in the world, which is widely cultured in several countries worldwide including Egypt. Aeromonas hydrophila infection showed a high prevalence in the farmed striped catfish negatively affecting its production causing economic loss. Therefore, the finding of functional feed supplements with antimicrobial activity is urgently needed. The use of marine seaweeds as feed supplements has produced satisfactory results as antibacterial agents. Accordingly, the present study was designed to evaluate the dietary effects of seaweeds mixture (Ulva lactuca, Jania rubens, and Pterocladia capillacea) extract (SME) on the growth performance, haemato-chemical parameters, antioxidant capacity, immune indices, and resistance of striped catfish fry against A. hydrophila infection. Four isonitrogenous (30% crude protein) diets were prepared to contain 0.0% (control), 1%, 2%, and 3% SME and were fed to striped catfish fry (1.7 ± 0.1 g) up to apparent satiety three times a day for 60 days. After the feeding trial, fish of each treatment were intraperitoneally injected with a virulent A. hydrophila strain and the relative percentage of survival (RPS) was recorded. The growth-stimulating activity of dietary SME was observed especially at 2% and 3% SME treatments. Similarly, haematological parameters (red blood cells, haemoglobin, haematocrit, and white blood cells) and serum protein profile (total protein, albumin, and globulin) were significantly (P < 0.05) improved, meanwhile serum alanine and aspartate aminotransferases were significantly (P < 0.05) decreased in fish fed with 2 and 3% SME diets. Serum creatinine and uric acid levels revealed no significant (P > 0.05) differences among the experimental groups. Hepatic malondialdehyde and serum nitrous acid levels were significantly decreased; meanwhile hepatic superoxide dismutase, catalase, and glutathione peroxidase levels were significantly increased in all SME-treated groups than the control one. Also, SME supplementations significantly increased the serum lysozyme, total immunoglobulin, and complement C3 activities with highest values at 2% and 3% SME treatments. Interestingly, after bacterial challenge, fish fed SME-supplemented diet were more resistant with the lowest fish mortality (15%) at the 3% SME diet, which exhibit the highest RPS (81.9%). Meanwhile the control group showed highest mortality (85%). According to the regression fitting curve, the current study recommends using the dietary SME with optimum levels of 2.25-2.5% to improve the growth performance, welfare status, and resistance of striped catfish fry against A. hydrophila infection.

Investigation of the Prevalence, Virulence Genes, and Antibiogram of Motile Aeromonads Isolated from Nile Tilapia Fish Farms in Egypt and Assessment of their Water Quality.

The aquaculture industry is a fast-growing sector in Egypt; however, the progress of this industry is impeded by many challenges such as poor water quality and associated bacterial infections. Among others, Motile Aeromonas Septicemia (MAS), caused by aeromonads, is among the most important bacterial diseases affecting aquaculture due to its zoonotic potential. In the present work, motile aeromonads were isolated from water samples (n= 8) and Nile tilapia (n= 240) in four fish farms (farms I, II, III, and IV) in Kafr El-Sheikh province during the period March to August 2017. This step was followed by investigation of the prevalence and phenotypic, molecular, and histopathological characterization of aeromonads. In addition, antimicrobial susceptibility and virulence gene detection were analyzed. Interestingly, physicochemical water analysis revealed different ranges in relation to the fish farms and seasons. More importantly, Aeromonas isolates were phenotypically identified in 33.3% and 12.5% from fish and water samples, respectively. The highest prevalence of motile aeromonads (46.7%) was recorded from farm IV, and only 12.5% of water samples were positive for them. Out of 80 isolates, 65 (81.25%) were molecularly identified at the genus level using gyrase B (gyrB). The prevalence of the virulence genes detected in the isolated motile aeromonads was aerolysin (aer), 52.2%; elastase (ahp), 26.25%; hemolysin (hyl), 35%; and lipase (lip), 3.75%. The antibiogram profile revealed that the highest resistance of aeromonads isolates (80%) was recorded to chloramphenicol, kanamycin, and azithromycin. Meanwhile, lower resistance levels of 40%, 30%, and 20% were found for streptomycin, cefotaxime, and amoxicillin, respectively. The multiple antibiotic resistance (MAR) index values ranged between 0.27 and 0.82 of motile aeromonads isolates. Furthermore, the histopathological examinations of naturally diseased tilapia revealed widespread hepatocellular necrosis with diffuse, numerous rod-shaped bacteria in liver with melanomacrophages and lymphocytic depletion with edema and hemosiderosis in the spleen. Our findings provide an updated epidemiological baseline for future reference and highlight the likely role of the adverse impact of water quality in the outbreaks of motile aeromonads with special reference to virulence genes and antibiotic resistant traits.

Diet Supplemented With Synthetic Carotenoids: Effects on Growth Performance and Biochemical and Immunological Parameters of Yellow Perch (Perca flavescens).

The current study assessed the effect of dietary canthaxanthin and lycopene supplementation at different concentrations on growth performance and antioxidant status in yellow perch (Perca flavescens). In this regard, fish with initial weight (32 ± 1.0 g) were divided into five groups in triplicate, and fed on carotenoid-free diet (control), canthaxanthin (CTX) (50 and 100 mg/kg diet), and lycopene (200 and 400 mg/kg diet) for 60 days. Growth parameters and antioxidant enzymes were evaluated after 30 and 60 days post feeding. Tissue liver and intestine from six fish per treatment was collected for antioxidant and digestive enzymes analysis. The results revealed a significant increase (P < 0.05) of lipid content in the group fed lycopene at a dietary level 400 mg/kg for 60 days, compared to the control. Moreover, dietary carotenoids exhibited no significant effect on growth performance; this was evidenced by no significant up-regulation of growth hormone (gh) and insulin-like growth factor 1b (igf-1b) genes after 30 and 60 days post feeding. Intestinal lipase and trypsin activities were significantly improved with dietary lycopene especially at a dose of (400 mg/kg diet) for 60 days. Malondialdehyde (MDA) level in liver was also significantly decreased with dietary lycopene (400 mg/kg diet) for 60 days. Hepatic superoxide dismutase (SOD), catalase (CAT), and Glutathione peroxidase (GSH-Px) activities were significantly decreased with dietary CTX, especially at dose (100 mg/kg diet) and lycopene at a concentration of 200 and 400 mg/kg diet after 60 days feeding. Additionally, the immune-related gene interleukin-1 beta (il-1b) mRNA expression level revealed up-regulation in groups fed on CTX at different concentrations for 30 days, and fish fed lycopene at a concentration level 400 mg/kg diet for 60 days. The obtained results concluded that dietary supplementation of canthaxanthin and lycopene could enhance immune response and maintain antioxidants defense of fish. Therefore, it considered as a functional aquafeed ingredient for yellow perch.

Dietary Withania sominefera root confers protective and immunotherapeutic effects against Aeromonas hydrophila infection in Nile tilapia (Oreochromis niloticus).

In the present study, effect of dietary Withania sominefera (W. sominefera) root powder was evaluated to modulate immune and antioxidant response against Aeromonas hydrophila (A. hydrophila) infection in Nile tilapia (Oreochromis niloticus). W. sominefera root powder supplemented diets at two concentrations 2.5% (W 2.5%) and 5% (W 5%); fed for 6 weeks prior to the A. hydrophila challenge and continued the same respective diets during the post challenge period (2 weeks). Results showed that fish fed W. sominefera at 5% enhanced immune response in both pre and post-challenge period. NBT level exhibited only significant increase (P < 0.05) in the pre-challenge period compared to control. Malondialdehyde (MDA) levels in liver and muscle revealed significant decrease in both Withania supplemented groups compared to the control in post challenge period. Antioxidant enzymes activities (catalase/CAT/, glutathione S-transferase/GST/, glutathione/GSH; and superoxide dismutase/SOD) were improved in liver and muscle in post challenge period. Glutathione peroxidase (GPx) level in muscle and serum total antioxidant capacity (TAC) showed a significant increase in both Withania supplemented groups compared to the control post challenge. Withania supplementation enhanced disease resistance against A. hydrophila and reduced mortalities (20%), especially at supplemented concentration of 5%. Our findings suggest that W. sominefera root powder may have protective and immunotherapeutic roles in Nile tilapia against A. hydrophila infection which may be useful in controlling important fish bacterial diseases.

Effect of vitamin C dietary supplementation in reducing the alterations induced by fenitrothion in Oreochromis niloticus.

The objective of this study was to investigate the dietary effect of vitamin C in amelioration some of studied alterations induced by fenitrothion in Nile tilapia (Oreochromis niloticus). Nile tilapia was exposed to sub-lethal concentration of fenitrothion 0.04 mg/l (96 h LC50 value was 0.8 mg/l), and basal diet was supplemented with two different dose of vitamin C (500 and 1200 mg/kg B wt/day) for 30 days. Vitamin C supplemented groups showed significant decrease in plasma cortisol and glucose level, enzymes activity of liver and gills (catalase, glutathione-S-transferase and superoxide dismutase) and % of tail DNA damage compared to exposed group. Moreover, fish revealed significant increase in total plasma protein, albumin, globulin and A/G ratio. High dose of vitamin C dietary supplementation (1200 mg/kg B wt/day) returns these parameters to its normal levels with no significant difference compared to non exposed control group. These results indicated that incorporation of high dose of vitamin C (1200 mg) in aqua feed for 30 days could be potentially less expensive and effective in reducing the alterations induced by fenitrothion in Nile tilapia.