This study evaluated the impacts of the probiotic, Lactobacillus sakei (L. sakei), and the extract of hawthorn, Crataegus elbursensis, on growth and immunity of the common carp exposed to acetamiprid. Fish ( mean ± SE : 11.48 ± 0.1  g) feeding was done with formulated diets ( T 1 (control): no supplementation, T 2 : 1 × 10 6   CFU / g LS (Lactobacillus sakei), T3: 1 × 10 8   CFU / g   LS , T 4 : 0.5% hawthorn extract (HWE), and T 5 : 1% HWE) for 60 days and then exposed to acetamiprid for 14 days. The growth performance improved in the fish fed LS at dietary level of 1 × 10 8   CFU / g , even after exposure to acetamiprid ( P < 0.05 ). Intestinal Lactobacillus sakei (CFU/g) load increased ( P < 0.05 ), following supplementation with the probiotic-enriched diet. The LS-treated fish had increases in the activity of digestive enzymes ( P < 0.05 ). Both LS and HWE stimulated antioxidant enzymes and immune system components in serum and mucus (alkaline phosphatase (ALP), protease, total Ig, and lysozyme) ( P < 0.05 ). However, the changes were different depending on the kind of the supplement. The malondialdehyde (MDA) levels decreased in HWE-treated fish after acetamiprid exposure ( P < 0.05 ). Both LS and HWE reduced the liver metabolic enzymes (LDH, ALP, AST, ALT, and LDH) in serum both before and after exposure to the pesticide ( P < 0.05 ). However, each enzyme exhibited a different change trend depending on the type of the supplement. HWE showed a stress-ameliorating effect, as glucose and cortisol levels declined in the HWE-treated fish ( P < 0.05 ). This study indicated the immunomodulatory impacts of LS ( 1 × 10 8   CFU / g ) and HWE (at dietary levels of 0.5–1%). The probiotic showed more performance compared to HWE. However, the HWE mitigated oxidative stress more efficiently than the probiotic.

The present study was conducted to evaluate the growth, immunity, haematology, antioxidant components and resistances to Aeromonas hydrophila infection in the common carp, Cyprinus carpio fed quercetin (QUR) enriched diet. A number of 360 fish (30.5 ± 1.5 g) were distributed into 12 tanks (30 fish/tank) in three replicates and fed experimental diets containing 0% (control), 0.1% (1 g/kg diet), 0.5% (5 g/kg diet) and 1% (10 g/kg diet) QUR for 60 days. Based on the results, the survival and growth performance (weight gain [%], specific growth rate and feed conversion ratio) improved in response to dietary QUR (p < 0.01). The analysis of fish body composition indicated higher content of protein in 0.5% and 1% QUR-supplemented fish compared to others (p < 0.01). The plasma (complement activity, IgM content, lysozyme activity, bactericidal activity, total protein, total albumin) and mucus (IgM content, lysozyme activity) immune components significantly increased almost all in the supplemented fish compared to those in the control group; however, the highest values were observed in group of 1% QUR (p < 0.01). The mucosal protease and alkaline phosphatase increased only in fish fed 1% QUR (p < 0.01). The expression of the immune-related genes (C3, Lyz and IgM) significantly increased in response to 0.5 and 1% QUR compared to control (p < 0.01). The expression of the inflammatory genes, tumour necrosis factorα (TNFα) and interleukin-8 (IL-8) significantly declined in fish fed 1% QUR compared to supplemented fish. The activity of liver antioxidant enzymes [superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT)] was also increased by QUR supplementation. The highest liver antioxidant enzyme activity was found in group of 1% QUR (p < 0.01). The QUR supplementation also affected haematology of the fish. In this regard, the values of RBC, Hct and WBC significantly elevated in response to dietary QUR (p < 0.01). The MCHC and MCH indices significantly increased in fish fed 0.5 and 1% QUR compared to other diets (p < 0.01). As an indicator of oxidative stress, the levels of malondialdehyde (MDA) showed no significant differences between the experimental groups (p > 0.01). The fish supplemented with 0.5 and 1% QUR significantly showed higher survival rate after challenge with A. hydrophila compared to other experimental groups (p < 0.01). In conclusion, QUR at optimal