Effects of α-sitosterol on growth, hematobiochemical profiles, immune-antioxidant resilience, histopathological features and expression of immune apoptotic genes of Nile tilapia, Oreochromis niloticus, challenged with Candida albicans.

In this study, the effect of the Streptomyces misakiensis metabolite (α- sitosterol, 0, 20, 40, 60, and 80 mg/kg) dietary supplementation on growth performance, antioxidant-immune stability and Candida albicans resistance of Nile tilapia was evaluated. The results revealed that the incorporation of α-sitosterol at doses of 60 and 80 mg/kg into the diet significantly improved the growth rate of Nile tilapia. The fish receiving 80 mg/kg showed an increased level of high-density lipoprotein, total protein, globulin, and albumin, and significantly reduced levels of indicators of hepato-renal damage, glucose, triglycerides, low-density lipoprotein, and total cholesterol. Dietary α-sitosterol induced a considerable increase in hepatopancreas glutathione peroxidase, superoxide dismutase and catalase activities and a significant drop in malondialdehyde levels. Supplementing the diet with 80 mg/kg of α-sitosterol increased nitric oxide, complement-3, nitro blue tetrazolium levels, lysozyme, and phagocytic activities. In particular, supplementing with α-sitosterol at 60-80 mg/kg of diet significantly enhanced the expression of pro/anti-inflammatory markers (il1b, il10, tgfb, ifng, tnfa and il8) after the C. albicans challenge. Also, there was a decrease in cumulative mortality percent, pro-apoptotic markers (casp3, bax and hsp70) and an increase in anti-apoptotic indicators (bcl2). Interestingly, following the C. albicans challenge, fish that received 0 and 20 mg α-sitosterol/kg exhibited significant inflammation in the hepatopancreas, spleen, and intestine. On the other hand, inflammation could be alleviated by feeding 60-80 mg α-sitosterol/kg. Due to these findings, α-sitosterol could be an innovative option to enhance growth, general physiological status, immune service, and antifungal resistance of Nile tilapia against C. albicans.

A novel metabolite of Streptomyces coeruleorubidus exhibits antibacterial activity against Streptococcus agalactiae through modulation of physiological performance, inflammatory cytokines, apoptosis, and oxidative stress-correlated gene expressions in Nile tilapia (Oreochromis niloticus).

Using the unique structures found in natural materials to produce new antibacterial drugs is crucial. Actinobacteria is well-known for its ability to produce naturally occurring chemicals with a variety of structural features that can be used as weapons against infectious bacteria. In the present study, the Streptomyces coeruleorubidus metabolites were characterized and their efficacy in suppressing Streptococcus agalactiae growth was carried out both in vitro and in vivo. The metabolites of S. coeruleorubidus were purified and identified as octasiloxane-hexadecamethyl (OHM). In vivo antibacterial activity of OHM revealed an inhibitory minimum concentration value of 0.5 µg/ml against S. agalactiae and induced ultrastructural cell changes revealed by scanning electron microscope. The safe concentration of OHM was determined as 0.8 mg/L for Nile tilapia. Four in vivo treatments were treated with 0 and 0.8 mg/L OHM and with or without challenge by S. agalactiae (1 × 107 CFU/mL) named control, OHM, S. agalactiae, and S. agalactiae + OHM groups. The OHM treatment improved the survival of Nile tilapia by 33.33% than S. agalactiae challenge group. Waterborne OHM treatment significantly mitigated the deleterious effects of S. agalactiae on hematological, hepato-renal functions, stress indicators, and antioxidant balance. OHM significantly alleviated nitric oxide levels, complement 3, IgM, and lysozyme activity, downregulation of liver antioxidant genes expression in S. agalactiae group. Furthermore, the addition of OHM to challenged fish with S. agalactiae-significantly reversed dramatic negative regulation of inflammatory, apoptosis, and immune related gene expression (caspase-3, bax, pcna, tnf-α, ifn-γ, il-8 il-1ß, il-10, tgf-ß, and bcl-2 in the Nile tilapia spleen. Additionally, the damaged hepatic and splenic structure induced by bacterial infection was restored with OHM treatment. Finally, S. coeruleorubidus metabolites (mainly OHM) revealed in vitro and in vivo antibacterial activity and showed alleviated effects on the physiological status of S. agalactiae infected tilapia.

Effects of extended dietary supplementation with Santalum album essential oil on hemato-biochemical changes, innate immune response, antioxidant status, and expression of related gene in Nile tilapia (Oreochromis niloticus).

The effects of long-term dietary supplementation with sandalwood (Santalum album L.) essential oil (SEO) was investigated on hemato-biochemical biomarkers, immune status, antioxidant capacity, and resistance against Staphylococcus aureus in Nile tilapia (Oreochromis niloticus). Five groups (with four replicates) of O. niloticus (12.60 ± 0.20 g) were fed diets supplemented with SEO at doses of 0, 0.5, 1.0, 2.0, and 4.0 mL/kg diet for 60 days. Results indicated a substantial increase in blood protein levels and lower serum cholesterol, cortisol, glucose, urea, creatinine levels and, transaminase activities of fish fed a 2.0-mL SEO/kg diet. Serum lysozyme activity, nitric oxide, complement-3 levels, and phagocytic activity were significantly improved in O. niloticus after 60 days of feeding SEO-supplemented diets. Dietary SEO at level of 2.0-mL SEO/kg diet increased the activities of SOD, CAT, and GPx, and decreased MDA levels in liver homogenate. In addition, dietary 2.0-mL SEO/kg diet significantly upregulated antioxidant genes expression (CAT, SOD, GPx, GST, and GSR) with downregulation of apoptotic genes (HSP70, TLR2, caspase-3, and PCNA) in the liver. Furthermore, SEO-enriched diets significantly down-regulated pro-inflammatory (TNF-α, IL-1ß, and IL-8) and up-regulated anti-inflammatory cytokine genes (TFG-ß and IL-10) in the spleen. Moreover, SEO fortification increased the relative percentage of survival against S. aureus challenge and regulated immune-antioxidant genes in the spleen after the challenge. Overall, the results revealed that long-term using SEO might strengthen the physiological performance, hepatic oxidant/antioxidant balance, innate immune response, and resistance of O. niloticus against bacterial infections.

Dietary Parsley Seed Mitigates Methomyl-Induced Impaired Growth Performance, Hemato-Immune Suppression, Oxidative Stress, Hepato-Renal Damage, and Pseudomonas aeruginosa Susceptibility in Oreochromis niloticus.

The present experiment investigated the potential protective role of parsley (Petroselinum crispum) seed meal (PSM) in alleviating methomyl (MET)-adverse impacts on growth, whole-body composition, hematological indicators, hepatorenal function, immune response, oxidative status, and disease resistance to Pseudomonas aeruginosa. For this purpose, 225 healthy Nile tilapia (Oreochromis niloticus) were allotted into five groups (45 fish/group in triplicate). One group was reared in clean water and fed a non-supplemented basal diet, while the other groups were exposed to 20.39 µg L-1 MET and fed a non-fortified basal diet or basal diets supplemented with 0.5, 1.0, or 2.0% of PSM for 60 days. The obtained data revealed significantly lower weight gain, feed intake, and specific growth rate, but higher feed conversion ratio and decreases in crude protein, lipid, and ash contents in the MET-exposed fish. Anemia, leukopenia, lymphocytopenia, and esonipenia were also obvious. Furthermore, MET-exposed fish had significantly higher serum levels of hepatic enzymes and renal damage products. Nevertheless, there was a significant depletion of enzymatic and non-enzymatic antioxidants and increased malondialdehyde, myeloperoxidase, and tumor necrosis factor-α levels in MET-exposed fish. The MET exposure significantly depressed lysozyme activity, nitric oxide, complement3, acetylcholinesterase activity, total proteins, globulin, and albumin levels in O. niloticus serum. Furthermore, pathological alterations in the liver and kidney were noted. The relative percentage of survival rate in MET-exposed fish was dramatically reduced on day 14 post-challenge with P. aeruginosa. The inclusion of PSM, on the other hand, greatly alleviated most of the MET-related negative effects. Taken together, the dietary intervention with PSM has a promising role in alleviating MET-deleterious impacts, rendering parsley seeds a viable aqua feed additive for O. niloticus.

Mannanoligosaccharides as a Carbon Source in Biofloc Boost Dietary Plant Protein and Water Quality, Growth, Immunity and Aeromonas hydrophila Resistance in Nile Tilapia (Oreochromis niloticus).

The aim of the present study was to evaluate mannan oligosaccharides (MOS) or glycerol (GLY) as a carbon source on biofloc systems of Nile tilapia (O. niloticus) juveniles. Fish (n = 750) were reared in open flow (Controls) or biofloc systems (B-GLY and B-MOS) fed with a plant or fish protein source over a period of twelve weeks. Total ammonia nitrogen and nitrate decreased in the biofloc groups, while biofloc volume increased in B-MOS. Compared to the controls, B-MOS and B-GLY exhibited higher weight gain and improved feed conversion, irrespectively of the diet. Serum level of C-reactive protein was reduced, while IgM and lysozyme activity was higher in the B-MOS fish, compared to other groups. Intestinal Bacillus spp. count was increased, whereas Vibrio, Aeromonas and Pseudomonas spp. counts decreased in B-MOS reared groups, compared to the other groups. The proinflammatory cytokine (IL-8 and IFN-γ) transcript expression was upregulated in B-MOS more than B-GLY reared groups. Compared to the controls, the virulence of Aeromonas hydrophila was decreased in the B-MOS and B-GLY groups. The results indicate several benefits of using MOS as a carbon source in a biofloc Nile tilapia system; a cost benefit analysis is required to assess the economic viability of this.

Effect of Chlorella vulgaris enriched diet on growth performance, hemato-immunological responses, antioxidant and transcriptomics profile disorders caused by deltamethrin toxicity in Nile tilapia (Oreochromis niloticus).

The toxic effect of deltamethrin (DM) was documented in aquaculture. There is no obtainable data on the effect of Chlorella vulgaris against DM toxicity. The current study focused on the effect of dietary supplementation with C. vulgaris (CV) on growth performance, innate immune response, antioxidant activities, and transcriptomics disorders induced by sub-lethal dose of DM in Oreochromis niloticus. A total number of 216 O. niloticus divided into four groups with tri-replicates. The 1st control group (CT) fed a basal diet, the second group fed diet enriched with 5% CV. The third group was exposed to DM (15 µg/L), where the last group fed CV and simultaneously exposed to DM as previous-mentioned. The procedure of CV feeding and DM exposure were continued for two months. Exposures to DM revealed in stunting of the growth parameters and lessening of survival ratio of tilapias with a significant decline of the erythrogram (macrocytic hypochromic anemic picture), and leucocytes immune cells and related parameters (immunoglobulin M, lysozyme) and sever shifting in the antioxidant indicators. Sever raise was monitored in hepatic and kidney markers. Also, genes expression related to immune and antioxidant parameters were severely impacted. Where tilapias received CV showed a significant increase in the growth and immune parameters besides to an improvement of hematological, antioxidant values and their related genes expressions. The fourth group that received CV simultaneous with DM exposure showed a soothing of the previous indicators and markers toward the values of tilapias fed on basal diet (CT). In turn, CV supplementation may be presented a protective effect alongside DM toxicity in O. niloticus appeared through soothing of the immune, antioxidant and related genes expressions in addition to its hepato-renal protective effects. Therefore, the current study recommended that an incorporating of 5% CV for tilapias diet could improve their growth performance, immunity, antioxidant and transcriptomics disorders induced by deltamethrin.

Dual immunological and oxidative responses in Oreochromis niloticus fish exposed to lambda cyhalothrin and concurrently fed with Thyme powder (Thymus vulgaris L.): Stress and immune encoding gene expression.

The present study was performed to explore the immunotoxicological effects of the lambda cyhalothrin (LCH) insecticide and evaluate the efficiency of Thyme powder (TP) as a fish supplement in attenuation of LCH impact on Oreochromis niloticus (O. niloticus) fish. Fish was sampled following 30-days exposure to LCH (1/6 LC50: 0.48 µg/L) and TP (2%) supplementation, individually or in combination. The growth performance, immune status, biochemical indices, and mRNA expression pattern changes of stress and immune-encoding genes in the liver and spleen tissues, respectively, through real-time polymerase chain reaction (RT-PCR) analysis, were evaluated. The findings showed that LCH exposure caused a significant lowering in most of the estimated variables including growth performance, hematological and immunological indices. Moreover, LCH disrupted the oxidant/antioxidant status and dysregulated the expression of stress and immune-related genes, downregulating the mRNA transcript level of Immunoglobulin M heavy chain (IgM), Interferon (IFN-γ), CXC-chemokine, and Toll-like receptors (TLR-7) in the spleen. However, mRNA expression of Myxovirus resistance (Mx) gene remained unaffected. In liver tissue, the heat shock protein (HSP-70) expression was upregulated, while that of cytochrome P450 1A (CYP 1A) was downregulated. TP (2%) supplementation elicited a significant modulation in aforementioned indices; however, their levels did not attain that of the control values. Our findings concluded that LCH affects the O. niloticus immune response through the negative transcriptional influence on genes linked to immunity and induction of oxidative injury of the immune organs. Besides, dietary TP (2%) could be a proper candidate to modulate the compromised immunity in response to LCH exposure in O. niloticus aquaculture.

Melamine and curcumin enriched diets modulate the haemato-immune response, growth performance, oxidative stress, disease resistance, and cytokine production in oreochromis niloticus.

Currently, feed adulteration and contamination with melamine (MEL) are considered one of the serious issues in the aquatic industry. With the limited studies of MEL exposure alone in fish, its adverse impacts on fish cannot be evaluated well. Accordingly, this study aimed to investigate the effects of MEL containing diets on the immune response, disease resistance to Aeromonas hydrophila, growth performance, chemical composition, immune-related genes expression, and histopathology of both spleen and head kidneys. Also, the efficacy of curcumin (CUR) dietary supplementation to alleviate MEL negative impacts were evaluated. A total of 180 apparently healthy Oreochromis niloticus (O. niloticus) were divided into four groups with three replicates fed the basal diet only, basal diet fortified with 200 mg/kg CUR, basal diet containing 1 % MEL, or a basal diet containing CUR + MEL. The results displayed that MEL significantly reduced growth performance indices and body crude lipid contents. Anemic, leukopenic, lymphocytopenic, heterocytopenic, esonipenic, hypoproteinemic and hypoalbuminic conditions were apparent. Moreover, depleted immune and antioxidant indicators including lysozyme activity, nitric oxide, immunoglobulin M, complement 3, glutathione peroxidase, and superoxide dismutase enzyme activity were recorded. Also, MEL reduced the disease resistance of O. niloticus to bacterial infection. Furthermore, MEL induced downregulation of mRNA levels of interleukin 1ß and tumor necrosis factor α in the spleen together with obvious pathological perturbations in both spleen and head kidneys. The CUR addition resulted in a significant enhancement in most indices. These results may conclude that MEL could alter both innate and adaptive immune responses via the negative transcriptional effect on immune-related genes together with the oxidative damage of the immune organs. Furthermore, CUR dietary supplements could be advantageous for mitigating MEL negative impacts, thus offering a favorable aquafeed additive for O. niloticus.

Effect of hexavalent chromium exposure on the liver and kidney tissues related to the expression of CYP450 and GST genes of Oreochromis niloticus fish: Role of curcumin supplemented diet.

The present study evaluated the adverse effects of the hexavalent chromium (Cr (VI)) at sub-lethal concentrations and the ameliorative potential of curcumin (CUR) over a sub-chronic exposure period on Oreochromis niloticus. Fish were exposed to Cr (VI) (4.57 mg/L) and CUR (0.02% in diet or 200 mg/kg diet), individually or in combination for 60-days. The growth rate during the period of experiment, condition factor, body composition, hepatosomatic index (HSI), hematological parameters, oxidative stress, apoptotic and DNA damage, branchial, hepato- and nephrotoxicity were estimated in this study. Moreover, the changes in mRNA expression of Cytochromes (CYP450) and glutathione S-transferase (GST) in kidney and liver tissues were assessed by qRT-PCR. Additionally, the concentration of metallothionine in the liver, histological investigation, and lesion scoring to the branchial, hepatic, renal and gill tissues were applied. The results revealed that Cr (VI) exposure caused a significant decline in most hematological variables and growth rate with down-regulation of CYP450 and GST expression. Histologically, Cr (VI) induced diverse forms of cell injury, vascular, and inflammatory alterations with upregulation of caspase-3 and downregulation of Bcl2 expression in the examined tissues. Additionally, it elevated the levels of serum MDA and 8-hydroxy-2' -deoxyguanosine than control. CUR-supplementation resulted in a significant improvement in most indices, amelioration of histological alterations and up-regulation of CYP450 and GST expression. These results may conclude that dietary supplements with CUR could be useful for modulation of the growth with protective effects to the branchial, hepatic, and renal tissues in response to Cr (VI) exposure, thereby presenting a promising feed additive for Nile tilapia in aquaculture.

Immune-protective, antioxidant and relative genes expression impacts of ß-glucan against fipronil toxicity in Nile tilapia, Oreochromis niloticus.

Our study is considered to attempt reducing the immune-toxic and antioxidant impacts of exposure to fipronil (FP) on Nile tilapia, Oreochromis niloticus using the ß-glucan (ßG). Two hundred and seventy fingerlings of Nile tilapia were divided randomly into six groups (45 tilapias of each, in 3 replicates): group I control (CT) group nourished on a basal diet. Group II (ßG) nourished a basal diet supplemented with 0.4% ßG. Groups III (1/20 FP) and V (1/10 FP) was exposed to 1/20 and 1/10 of the 96 h LC50 of FP in water and nourished the basal diet respectively. Groups IV (1/20 FP+ ßG) and VI (1/10 FP+ ßG) were exposed to 1/20 and 1/10 FP concomitantly with 0.4% ßG supplementation for 90 successive days. Growth performance metrics were higher in ßG group than CT. While those metrics were fallen at exposure to 1/20 or 1/10 FP. Supplementation with ßG elevated the IgM and lysozyme levels.Whereas, tilapias exposed to FP only at different concentration showed lowering of those compared to CT. Supplementation with ßG was effectively augmented IgM and lysozyme in 1/20 FP exposed tilapias. Furthermore, in a minor grade at 1/10 FP exposed tilapias. Exposure to FP increased the activities of hepatic markers chiefly at 1/10, however the ßG supplementation was successfully improved these markers. There was imbalance of cortisol level at FP exposure where, ßG combining to FP alleviate this disparity. There was fallen in LDH, MDH and FDPase in ßG tilapias where continuing raise in 1/10 FP followed by 1/20 FP. ßG supplementation raise the level of GSH, without significant variations in MDA conversely occurs in FP alone. Genes expression of ßG caused raise of both GPx and GR, without fluctuations in CAT and SOD. Exposure to FP diminishes all evaluated antioxidant genes. It could fulfilled that supplementation with ßG successfully alleviated the immune-toxic and antioxidant impact of FP in tilapias.

Sublethal concentrations of di-n-butyl phthalate promote biochemical changes and DNA damage in juvenile Nile tilapia (Oreochromis niloticus).

Increase in consumption of consumer items such as plasticizers have resulted in a sharp rise in the presence of xenobiotics like phthalic acid esters (PEs) in freshwater and marine environments due to contaminated runoff and improper release of effluents. The sublethal toxicity of Di-n-butyl phthalate (DBP) was investigated in juvenile Nile tilapia, Oreochromis niloticus, in an attempt to determine the biological effect of exposure to 1/2 and 1/3 median lethal concentration (96-h LC50) which, in our study was experimentally determined to be 11.8 mg/l. Following four days of exposure, indices of the oxidative potential [Malondialdehyde content (MDA)], antioxidant parameters [superoxide dismutase activity (SOD) and reduced glutathione level (GSH)] and DNA damage were evaluated by single-cell gel electrophoresis (Comet assay). Hepato-renal markers [alanine aminotransferase activity (ALT), creatinine and urea level] and cortisol levels were also quantified in serum. Additionally, histopathological investigations of liver, kidney and gill tissues were conducted. Comparative results between the 1/2 96-h LC50 group and the 1/3 96-h LC50 group clearly showed that there was a significant elevation in MDA levels and a marked increase in DNA damage in addition to inhibition of antioxidant barriers as represented by attenuation of SOD activity and GSH level in the group that was exposed to higher concentration of DBP (1/2 96-h LC50). The hepatorenal markers and cortisol levels were also observed to be elevated. Histopathological examination of the liver, kidney and gills showed pathological alterations that could be correlated with changes in the biochemical profile of the exposed fish. Additionally, anomalous clinical signs were noted. Based on these findings, we conclude from our study that exposure of juvenile O. niloticus to DBP has the potential to induce biochemical as well as tissue morphological alterations associated with oxidative injury and DNA damage.