The synergistic effects of plant polysaccharide and Pediococcus acidilactici as a synbiotic additive on growth, antioxidant status, immune response, and resistance of Nile tilapia (Oreochromis niloticus) against Aeromonas hydrophila.

This study evaluated the growth performance, immune responses, and disease resistance of Nile tilapia upon pistachio hulls derived polysaccharide (PHDP) and Pediococcus acidilactici (PA) separately or as synbiotic. Fish received four types of diets: T1, control; T2, PHDP (0.1%); T3, PA (0.2%); T4, PHDP (0.1%) +PA (0.2%) for 56 days. The results showed that final weight and weight gain were markedly higher in fish fed T4 diet than that given T1 and T2 diets (P ≤ 0.05). In addition, a significantly greater specific growth rate was obtained by the T4 diet compared to the control. Fish survival was significantly improved in all supplemented diets compared to the control. On the other hand, the activities of lipase, protease, and amylase showed significant increases in the T4 group compared with other feeding groups. The total leucocytes and lymphocytes proportion significantly elevated in T3 and T4 than remaining groups (P ≤ 0.05). Further, fish fed T3 diet presented significantly higher serum total protein, total immunoglobulin, lysozyme activity (LYZ), alternative complement activity (ACH50), and alkaline phosphatase activity compared to fish fed T1 and T2 diets, while the mentioned indices were found significantly highest in T4 group than others. Fish received T3 and T4 diets had higher skin mucus LYZ and ACH50 than those fed T1 and T2 diets (P ≤ 0.05). The malondialdehyde levels were significantly declined in T3 and T4 when compared to the control. Fish fed T3 and T4 diets demonstrated significantly enhanced superoxide dismutase, catalase, and glutathione peroxidase activities compared to the control. The intestinal propionic acid significantly increased by T2 and T4 diets, while the highest levels of acetic acid detected in fish given T4 diet. The expression levels of tumor necrosis factor α (TNF-α), interleukin 1ß (IL-1ß), and interleukin 10 (IL-10) were significantly affected by T3 and T4 supplements. The efficacy of T4 diet against Aeromonas hydrophila infection was documented by a significantly lower mortality rate. In conclusion, the combination of PHDP and PA presented promising results as a synbiotic feed additive for Nile tilapia.

Pistachio hull polysaccharide protects Nile tilapia against LPS-induced excessive inflammatory responses and oxidative stress, possibly via TLR2 and Nrf2 signaling pathways.

Polysaccharides are polymeric carbohydrates found in living organisms, which have several physiological functions. In the present study, Nile tilapia (Oreochromis niloticus) were fed diets containing three levels (0%, 0.2%, and 0.6%) of Pistacia vera hull polysaccharide (PHP) for 45 days and then injected with PBS or bacterial lipopolysaccharide (LPS). Before the LPS challenge, Nile tilapia fed 0.2% and 0.6% PHP showed significantly increased mean final weight and weight gain compared to those received 0% PHP. The specific growth rate and feed conversion ratio were significantly improved in the treatment fed 0.6% PHP compared to the remaining groups. After LPS challenge, the activities of liver antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase exhibited the highest values in the 0.6% PHP group. Malondialdehyde (MDA) levels were significantly augmented in the model (fed 0% PHP diet and injected with LPS) and 0.2% PHP groups compared to the control. However, MDA showed decreased levels in the 0.6% PHP group. LPS induced higher mRNA and/or protein levels of Toll-like receptor 2 (TLR2), nuclear factor kappa B (NF-κB), myeloid differentiation primary response protein 88 (Myd88), tumor necrosis factor α (TNF-α), interleukin 1ß (IL-1ß), and interferon γ (IFN-γ) in Nile tilapia liver. However, PHP administration significantly upregulated the expression of interleukin 10 (IL-10), nuclear erythroid 2-related factor 2 (Nrf2), SOD, and CAT, but markedly suppressed TLR2, NF-κB, Myd88, and pro-inflammatory cytokine expression and/or production in the liver. The findings of the current study indicated that PHP has positive effects on growth performance, immune gene-related expression, and antioxidative activities. We can conclude that PHP can attenuate LPS-induced oxidative stress and inflammatory responses in vivo, possibly via induction of Nrf2 and blockade of TLR2/Myd88/NF-κB pathways in Nile tilapia.

Dose-dependent and gender-related radiation-induced transcription alterations of Gadd45a and Ier5 inhuman lymphocytes exposed to gamma ray emitted by (60)Co.

Growth arrest DNA damage-inducible 45a gene (Gadd45a) and immediate early response gene 5 (Ier5) have been emphasised as ideal radiation biomarkers in several reports. However, some aspects of radiation-induced transcriptional alterations of these genes are unknown. In this study, gender-dependency and dose-dependency as two factors that may affect radiation-induced transcription of Gadd45a and Ier5 genes were investigated. Human lymphocyte cells from six healthy voluntary blood donors (three women and three men) were irradiated in vitro with doses of 0.5-4.0 Gy from a (60)Co source and RNA isolated 4 h later using the High Pure RNA Isolation Kit. Dose and gender dependency of radiation-induced transcriptional alterations of Gadd45a and Ier5 genes were studied by quantitative real-time polymerase chain reaction. The results showed that as a whole, Gadd45a and Ier5 gave responses to gamma rays, while the responses were independent of radiation doses. Therefore, regardless of radiation dose, Gadd45a and Ier5 can be considered potential radiation biomarkers. Besides, although radiation-induced transcriptional alterations of Gadd45a in female and male lymphocyte samples were insignificant at 0.5 Gy, at other doses, their quantities in female samples were at a significantly higher level than in male samples. Radiation-induced transcription of Ier5 of females samples had a reduction in comparison with male samples at 1 and 2 Gy, but at doses of 0.5 and 4 Gy, females were significantly more susceptible to radiation-induced transcriptional alteration of Ier5.