Efficacy of dietary yeast cell wall supplementation on the nutrition and immune response of Nile tilapia

Prebiotics are non-digestible carbohydrates that improve the animal health via modulation of their intestinal beneficial organisms. Immunowall® is a commercial prebiotic consists of high concentration of yeast β-glucan (βG) and Mannan-oligosaccharides (MOS). The current study was designed to investigate the prebiotic potential of Immunowall® on nutrition and health performance of Nile tilapia Oreochromis niloticus. Three fish groups were nourished on control diet supplemented with 0%, 0.1% and 0.2% Immunowall® for two months. Both dietary levels of Immunowall® exhibited significant increase in growth parameters (P ≤ 0.05) as well as in white blood cell count, total protein, and globulin concentrations. While, the immune parameters such as antioxidant biomarkers (catalase and glutathione-reductase), non-specific immune response (e.g. phagocytic activity, phagocytic index and lysozyme activity) and immune-related genes expressions (e.g. TNF-α and IL-1β) were higher in 0.2% Immunowall® compared to 0.1% Immunowall® and control. Oral administration of β-glucan and MOS mixture reduced the mortalities after microbial infections with L. gravieae and A. hydrophila. Therefore, we can recommend the dietary inclusion of Immunowall® in aqua-feed as an efficient method to achieve feasible and sustainable fish production. Keywords: β-Glucan, MOS, Immunity, Growth, Challenge, Nile tilapi

Dietary effect of soybean lecithin on the growth performance, digestive enzyme activity, blood biomarkers, and antioxidative status of striped catfish, Pangasianodon hypophthalmus.

Soybean lecithin (SBL) is usually added to aquafeed as a lipid source because aquatic animals cannot synthesize phospholipids. Hence, this study aimed to investigate the role of SBL on the growth, nutrient consumption, digestive enzyme activity, blood parameters, and antioxidant capability of striped catfish. The fish were fed on five experimental diets with five grading levels of SBL (0, 2, 4, 6, and 8%) for 60 days. The final weight, weight gain, specific growth rate, feed intake, and protein efficiency ratio were markedly higher in striped catfish treated with 2-4% SBL than the control level (0% SBL). However, the lowest feed conversion ratio was in the fish-fed groups of 4-6% SBL. The carcass lipid content was significantly higher in fish fed 2-4% SBL compared to the control level (0% SBL). The lipase, amylase, and protease activities were significantly increased in the fish fed 2-6% SBL compared to 0% SBL-fed group. The gradually increased levels of SBL improved the structural appearance and increased the intestinal villi length and branching appearance. The triglycerides and total cholesterol were increased in the fish fed with 4, 6, and 8% compared to the control level, with the highest being in the fish fed with 8%. The lysozyme activity was higher in the fish fed with 2, 4, and 6% of SBL compared to the control level, with higher activity in the fish fed with 2 and 4% than 6%. Superoxide dismutase, glutathione peroxidase, and catalase activities were increased in the fish fed with 2, 4, and 6% SBL. The malondialdehyde level was lower in the fish fed with 4-6% SBL compared to the control level. The regression analysis revealed that the optimum dose of SBL is required at 3.65-4.42% for better productivity and health performances in striped catfish

Neem leaf powder (Azadirachta indica) mitigates oxidative stress and pathological alterations triggered by lead toxicity in Nile tilapia (Oreochromis niloticus)

Abstract This study investigated the clinical and pathological symptoms of waterborne lead toxicity in wild Nile tilapia collected from a lead-contaminated area (the Mariotteya Canal: Pb = 0.6 ± 0.21 mg L−1) and a farmed fish after 2 weeks of experimental exposure to lead acetate (5–10 mg L−1) in addition to evaluating the efficacy of neem leaf powder (NLP) treatment in mitigating symptoms of lead toxicity. A total of 150 fish (20 ± 2 g) were alienated into five groups (30 fish/group with three replicates). G1 was assigned as a negative control without any treatments. Groups (2–5) were exposed to lead acetate for 2 weeks at a concentration of 5 mg L−1 (G2 and G3) or 10 mg L−1 (G4 and G5). During the lead exposure period, all groups were reared under the same conditions, while G3 and G5 were treated with 1 g L−1 NLP. Lead toxicity induced DNA fragmentation and lipid peroxidation and decreased the level of glutathione and expression of heme synthesis enzyme delta aminolaevulinic acid dehydratase (ALA-D) in wild tilapia, G2, and G4. NLP could alleviate the oxidative stress stimulated by lead in G3 and showed an insignificant effect in G5. The pathological findings, including epithelial hyperplasia in the gills, edema in the gills and muscles, degeneration and necrosis in the liver and muscle, and leukocytic infiltration in all organs, were directly correlated with lead concentration. Thus, the aqueous application of NLP at 1 g L−1 reduced oxidative stress and lowered the pathological alterations induced by lead toxicity

Growth performance of striped catfish fed dietary soybean lecithin for 60 days.

Growth performance of striped catfish fed dietary soybean lecithin for 60 days.</p

Carcass composition of striped catfish fed dietary soybean lecithin for 60 days.

Carcass composition of striped catfish fed dietary soybean lecithin for 60 days.</p

Blood biochemical indices of striped catfish fed dietary soybean lecithin for 60 days.

Blood biochemical indices of striped catfish fed dietary soybean lecithin for 60 days.</p

Fig 2 -

Histomorphology of the middle intestine of striped catfish in the control fish (A; 0%) and gradually increased levels of soybean lecithin (B, C, D, E; 2, 4, 6, 8% respectively) showing evident enrichment and branching of intestinal villi (blue arrowhead) by increased levels of soybean lecithin in the supplemented diet. Stain H&E. Bar = 100 μm.</p

Blood immunity and antioxidative responses of striped catfish fed dietary soybean lecithin for 60 days.

Blood immunity and antioxidative responses of striped catfish fed dietary soybean lecithin for 60 days.</p

Fig 1 -

Polynomial regression analysis (Pn = 9).</p

Formulation and composition of the basal diet.

Soybean lecithin (SBL) is usually added to aquafeed as a lipid source because aquatic animals cannot synthesize phospholipids. Hence, this study aimed to investigate the role of SBL on the growth, nutrient consumption, digestive enzyme activity, blood parameters, and antioxidant capability of striped catfish. The fish were fed on five experimental diets with five grading levels of SBL (0, 2, 4, 6, and 8%) for 60 days. The final weight, weight gain, specific growth rate, feed intake, and protein efficiency ratio were markedly higher in striped catfish treated with 2–4% SBL than the control level (0% SBL). However, the lowest feed conversion ratio was in the fish-fed groups of 4–6% SBL. The carcass lipid content was significantly higher in fish fed 2–4% SBL compared to the control level (0% SBL). The lipase, amylase, and protease activities were significantly increased in the fish fed 2–6% SBL compared to 0% SBL-fed group. The gradually increased levels of SBL improved the structural appearance and increased the intestinal villi length and branching appearance. The triglycerides and total cholesterol were increased in the fish fed with 4, 6, and 8% compared to the control level, with the highest being in the fish fed with 8%. The lysozyme activity was higher in the fish fed with 2, 4, and 6% of SBL compared to the control level, with higher activity in the fish fed with 2 and 4% than 6%. Superoxide dismutase, glutathione peroxidase, and catalase activities were increased in the fish fed with 2, 4, and 6% SBL. The malondialdehyde level was lower in the fish fed with 4–6% SBL compared to the control level. The regression analysis revealed that the optimum dose of SBL is required at 3.65–4.42% for better productivity and health performances in striped catfish.</div