Effect of dietary intervention with Capsicum annuum extract on growth performance, physiological status, innate immune response, and related gene expression in Nile tilapia.

The red pepper (Capsicum annuum) has gained great attention recently because of its biological and pharmacological characteristics. The present approach aimed to evaluate the effects of C. annuum alcoholic extract (CAE) supplementation on Nile tilapia (Oreochromis niloticus) growth performance, physiological status, some metabolic, immune, and regulatory genes expression, and resistance against Streptococcus agalactiae infection. Fish (22.26 ± 0.19 g) were assigned to four treatments (five replicates, each with 10 fish replicate-1) and fed tested diets for 60 days. The experimental diets were supplemented with CAE at 0, 0.4, 0.8, and 1.6 g kg-1, expressed as CAE0, CAE0.4, CAE0.8, and CAE1.6, respectively. The findings exhibited that CAE dietary supplementation improved growth performance, feed utilization, elevated growth hormone level, and digestive enzyme activities (amylase and protease), and lowered leptin hormone in a level-dependent manner. Boosting the mRNA expression of the transporter proteins (solute carrier family 15 member 2 and solute carrier family 26 member 6) and insulin-like growth factor-1 genes with a decrease in the myostatin gene expression was noticed in the CAE-fed groups. The innate immune (serum bactericidal activity %, complement 3, and phagocytic activity %) and antioxidant (glutathione peroxidase and total antioxidant capacity) parameters were significantly (p < 0.05) improved, and the serum malondialdehyde level was significantly decreased by CAE dietary inclusion. A marked upregulation in the mRNA expression of interleukins (il-1ß, il-6, il-8, and il-10), transforming growth factor-ß, glutathione peroxidase, and glutathione synthetase genes were observed in CAE-fed groups. Dietary CAE decreased the cumulative mortalities after the challenge with S. agalactiae by 20, 13.33, and 10% in CAE0.4, CAE0.8, and CAE1.6, respectively, compared to the control (40%). Overall, dietary supplementation with CAE could improve growth performance and physiological status, and modulate the expression of several regulatory genes in Nile tilapia. The recommended level of CAE is 1.6 g kg-1 to augment growth and health status.

Endosulfan toxicity in Nile tilapia (Oreochromis niloticus) and the use of lycopene as an ameliorative agent.

OBJECTIVES: Endosulfan is a broad-spectrum organochlorine insecticide that has been commercially in use for decades to control insect pests and has been found to pollute the aquatic environment. The current study was carried out to investigate the toxic effects of endosulfan, an organochlorine pesticide, on Nile tilapia (Oreochromis niloticus), a freshwater fish, and the alleviating effects of lycopene on the induced toxicity. METHODS: Four treatment groups of fish were investigated (3 replicates of 15 fish for each group): (1) a control group, (2) a group exposed to endosulfan, (3) a group that was fed on a basal diet supplemented with lycopene, and (4) a group that was fed on a basal diet supplemented with lycopene and exposed to endosulfan. The experiment was carried out over a 4-week period. RESULTS: Endosulfan negatively affected liver function, including liver enzymes and plasma proteins. Endosulfan affected blood parameters of fish and reduced the counts of red blood cells (RBCs) and white blood cells (WBCs), as well as affected immunological parameters. Endosulfan caused oxidative stress, as it decreased the values of antioxidants catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPX), and glutathione (GSH), and increased the level of lipid peroxide malondialdehyde (MDA). Additionally, endosulfan increased cytochrome P450 (CYP450) levels, while it decreased glutathione S-transferase (GST) mRNA transcript levels and distorted the normal histological structure of the liver, gills, and spleen of affected fish. Conversely, lycopene partially restored the aforementioned parameters when administered concomitantly with endosulfan. CONCLUSION: The results showed the beneficial effects of supplementing fish diets with lycopene as a natural antioxidant for ameliorating the toxicity caused by endosulfan.

Nephroprotective and antioxidant significance of selenium and α-tocopherol on lead acetate-induced toxicity of Nile Tilapia (Oreochromis niloticus).

The kidney plays an important physiological function, maintaining the osmoregulation and electrolyte balance of Nile tilapia (Oreochromis niloticus). Selenium and α-tocopherol (α-toc) are potent antioxidants, which improve the aquaculture health. In this study, we tested the potential ability of selenium and α-toc to alleviate the oxidative stress in the kidney induced by lead toxicity. Two hundred and twenty-five O. niloticus were divided into five groups. The control group received a basal diet. Lead nephrotoxicity was induced by daily application of 73.40 mg lead acetate/liter water for up to 10 weeks. Selenium and α-tocopherol were given 1 week before lead intoxication. Selenium was administered as sodium selenite, 4 mg/kg dry diet. Alpha-tocopherol acetate was administered as α-toc, 200 mg/kg dry diet. The last group received a mixture of selenium and α-toc in diet. Fish treated with selenium and/or α-toc (groups III-V) showed an amelioration of the adverse effects of lead toxicity and significant improvement in serum electrolytes (calcium, inorganic phosphate, and magnesium) and creatinine level compared with the positive control group (P ≤ 0.05). Treated groups showed significant decrease in superoxide dismutase (SOD) and reduced glutathione (GSH) activity with significant increase in malondialdehyde (MDA; P ≤ 0.05). It could be concluded that selenium and α-toc have a potential antioxidant effect and have the ability to improve the kidney function after lead intoxication of O. niloticus.