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This study presents a novel approach to sustainable aquaculture by integrating biofloc technology (BFT) with a compact down-flow hanging sponge (DHS) reactor. The integrated BFT-DHS system effectively removed nitrogen compounds while maintaining ammonia-nitrogen (NH4+-N) concentrations below 1 mg-N L-1 without water exchange. Application of this system in a tank bred with juvenile Oreochromis niloticus showed a high NH4+-N removal rate of up to 97 % and nitrite (NO2- -N) concentrations were maintained at 0.1 ± 0.1 mg-N L-1. Microbial analysis revealed Gordonia as the predominant genus in the biofloc contributing to heterotrophic nitrification, while the Peptostreptococcaceae family dominated the DHS reactor. Heterotrophic nitrification seemed to be the primary process for enhanced nitrogen removal. Pathogenic bacteria, Vibrio sp. was absent throughout the study. This study highlights the potential integration of BFT and DHS system for sustainable aquaculture practice with effective nitrogen removal.
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This study aimed to investigate the toxic effects of benzalkonium chloride (BAC) on Oreochromis mossambicus, a freshwater fish species. Probit analysis was used to determine the lethal concentration (LC50) of BAC for different exposure periods (24, 48, 72, and 96 h). The viability of fish exposed to BAC was assessed using the general threshold survival models (GUTS) and confirmed with relevant datasets to evaluate model accuracy. Experimental groups of fish were exposed to BAC concentrations equivalent to 10% and 20% of the 96-h LC50 for 45 days. The study revealed significant alterations in various parameters during sublethal BAC exposure. These effects included decreased specific growth rate (SGR), red blood cell count (RBC), hemoglobin (Hb) concentration, hematocrit (Ht) value, plasma protein, and albumin levels, as well as acetylcholinesterase (AChE) activities in both gills and liver. Additionally, an increase in gastrosomatic index (GSI), feed conversion ratio (FCR), plasma glucose and creatinine concentrations, alanine aminotransferase (ALT), aspartate aminotransferase (AST) enzymatic activities, catalase (CAT), superoxide dismutase (SOD), and malondialdehyde (MDA) levels were observed in the exposed fish's gills and liver. Furthermore, the study found that glutathione S-transferase (GST) and glutathione peroxidase (GPx) levels initially increased and then decreased in both gills and liver after exposure to BAC. Correlation matrix analysis, multivariate multiple regression (MMR), canonical correspondence analysis (CCA), integrated biomarker response (IBR), and biomarker response index (BRI) were utilized to assess the impact of BAC on fish, highlighting significant effects on multiple biomarkers in O. mossambicus following surfactant exposure. Thus, the study provides valuable insights into the toxic effects of BAC on this fish species, emphasizing the importance of monitoring such pollutants in aquatic environments.
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Compuestos de Benzalconio , Biomarcadores , Tilapia , Animales , Biomarcadores/metabolismo , Compuestos de Benzalconio/toxicidad , Contaminantes Químicos del Agua/toxicidadRESUMEN
As one of subunits for interleukin-2 receptor (IL-2R), CD122 can bind to IL-2 and then activate downstream signal transduction to participate in adaptive immune response. Although CD122 has been identified and investigated from several teleost species, studies on its function at T-cell level are still scarce for lack of specific antibodies. In this study, a typical CD122 in Nile tilapia (Oreochromis niloticus) was characterized by bioinformatics analysis, cloned to produce retrovirus infected NIH/3T3 cells for mouse immunization. After cell fusion and screening, we successfully developed a mouse anti-tilapia CD122 monoclonal antibody (mAb), which could specifically recognize CD122 and identify CD122-producing T cells of tilapia. Using the mAb to detect, CD122 was found to widely distribute in immune-related tissues, and significantly elevate post Edwardsiella piscicida infection or T-cell activation. More importantly, the expansion of CD122+ T cells and up-regulation of CD122 occurred both in total T cells and T-cell subsets during T-cell activation upon in vitro stimulation or in vivo infection. These results indicate that CD122 can be used as a T-cell activation marker in tilapia. Notably, CD122 mAb blocking blunted the activation of MAPK/Erk and mTORC1 pathways, and inhibited T-cell proliferation, suggesting a critical role of CD122 in ensuring proper proliferation of tilapia T cells. Therefore, this study enriches the knowledge of T-cell responses in fish and provides new evidence for understanding the evolution of lymphocyte-mediated adaptive immunity.
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Cíclidos , Enfermedades de los Peces , Proteínas de Peces , Subunidad beta del Receptor de Interleucina-2 , Linfocitos T , Animales , Cíclidos/inmunología , Enfermedades de los Peces/inmunología , Proteínas de Peces/genética , Proteínas de Peces/inmunología , Linfocitos T/inmunología , Subunidad beta del Receptor de Interleucina-2/inmunología , Subunidad beta del Receptor de Interleucina-2/genética , Activación de Linfocitos , Infecciones por Enterobacteriaceae/inmunología , Infecciones por Enterobacteriaceae/veterinaria , Proliferación Celular/efectos de los fármacos , Filogenia , Ratones , Secuencia de Aminoácidos , Alineación de Secuencia/veterinaria , BiomarcadoresRESUMEN
Secreted by natural killer cells and cytotoxic T lymphocytes, Granzyme B is involved in regulating the adaptive immune response in vertebrates and plays a pivotal role in resisting virus invasion and removing pathogens. Although it had been extensively studied in mammals, the involvement of Granzyme B in adaptive immune response of early vertebrates remained elusive. In this study, we investigated the Granzyme B in Oreochromis niloticus (OnGrB), found that its function domain was conserved. Additionally, OnGrB was widely expressed in various tissues and could respond to T-cell activation in vitro at the transcriptional level. Furthermore, we prepared the recombinant OnGrB (rOnGrB) as an immunogen to develop a mouse anti-OnGrB monoclonal antibody (mAb). Using this anti-OnGrB mAb as a tool, we explored the expression of OnGrB in the adaptive immune response of tilapia. Our findings revealed that T cell was a significant source of OnGrB production, the expression of OnGrB at the protein level and the proportion of OnGrB + T cells increased after both T cell activation in vitro and infection with Edwardsiella piscicida in vivo. More importantly, our findings also preliminarily illuminated that p65 could regulate the transcriptional activity of OnGrB. These results indicated that OnGrB was involved in the adaptive immunity of tilapia and played a critical role in T cell function in teleost. Our study provided theoretical support and new perspectives for understanding adaptive immunity in teleost.
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Cíclidos , Edwardsiella , Infecciones por Enterobacteriaceae , Enfermedades de los Peces , Proteínas de Peces , Granzimas , Animales , Inmunidad Adaptativa , Secuencia de Aminoácidos , Cíclidos/inmunología , Cíclidos/genética , Edwardsiella/inmunología , Edwardsiella/fisiología , Infecciones por Enterobacteriaceae/inmunología , Infecciones por Enterobacteriaceae/veterinaria , Enfermedades de los Peces/inmunología , Proteínas de Peces/genética , Proteínas de Peces/inmunología , Perfilación de la Expresión Génica/veterinaria , Regulación de la Expresión Génica/inmunología , Granzimas/genética , Granzimas/inmunología , Granzimas/metabolismo , Filogenia , Alineación de Secuencia/veterinaria , Linfocitos T/inmunologíaRESUMEN
The molecular chaperone heat shock proteins 70 (Hsp70) play a pivotal role in preserving cellular integrity and managing stress. This study extensively examined two Hsp70 proteins, On-Hsp70cBi, inducible, and On-Hsp70cBc, constitutively expressed, in Nile tilapia (Oreochromis niloticus) utilizing in silico analysis, homology modeling, and functional annotation. Employing the SWISS-MODEL program for homology modeling, the proposed models underwent thorough reliability assessment via ProSA, Verify 3D, PROVE, ERRAT, and Ramachandran plot analyses. Key features of On-Hsp70cBi and On-Hsp70cBc included amino acid lengths (640 and 645) and molecular weights (70,233.48 and 70,773.17 Da). Moreover, theoretical isoelectric points (pI = 5.63 and 5.28), indicated their acidic nature. Counts of negatively and positively charged residues (95 and 86; 95 and 81) revealed neutrality, while instability index (II) values of 35.27 (On-Hsp70cBi) and 38.85 (On-Hsp70cBc) suggested stability. Aliphatic index (AI) values were notably high for both proteins (84.58 and 82.85), indicating stability across a broad temperature range. Domain architecture analysis showed both proteins to contain an MreB/Mbl domain. Protein-protein interaction analysis identified the co-chaperone Stip1 as a primary functional partner. Comparative modeling yielded highly reliable 3D models, showcasing structural similarity to known proteins and predicted binding sites. Additionally, both proteins are primarily localized in the cytoplasm. Functional analysis predicted an AMP-PNP binding site for On-Hsp70cBi and an ATP binding site for On-Hsp70cBc. These findings deepened our understanding of Hsp70cBc and Hsp70cBi in Nile tilapia, underscoring their significance in fish physiology and warranting further investigation, thus advancing our knowledge of these proteins' roles in cellular processes and stress responses, potentially impacting fish health and resilience.
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Nowadays, nanomaterials enter high numbers of daily used products and drug manufacture. A nanocomposite of vitamins C (VC) and vitamin E (VE) with chitosan as a vehicle and protector was used in a comparative eight-week feeding study, Nile tilapia weighing 31.2 ± 0.36 g distributed in seven groups and fed (G1) basal diet, (G2) bulk VC, (G3) VC- nanoparticles (NPs), (G4) bulk VE, (G5) VE-NPs, bulk VCE (G6), and (G7) VC plus VE (VCE)-NPs, respectively. The Nile tilapia-fed nanocomposite vitamins had significantly higher growth performance compared to the control; VCE-NPs had the superiority among tested supplementations where total weight gain (63.6 g), daily weight gain (1.13 g), relative growth rate (206.1%) with lower feed conversion rate (1.6) and insignificant feed intake (101.5 g). Overall, the level of liver enzymes was significantly decreased in fish serum after eight-week nanocomposite supplementation, and dietary VCE-NPs caused a significant reduction of serum AST (18.45 IU/L) and ALT (14.77 IU/L) compared to the control 25.5 IU/L and 17.6 IU/L, respectively. Fish fed dietary VCE-NPs, VC-NPs, and VE-NPs had significant enhancement of RBCs 4.2 × 106/µL, 3.8 × 106/µL, and 3.55 × 106/µL; WBCs 46.15 × 103, 42.9 × 103, and 44 × 103/µL, respectively, Also TP was significantly higher 6.38 g/dL in VCE-NPs group compared to the control and the other treatments. Over all, the dietary nanocomposite vitamins boost the innate immunity of the experimental Nile tilapia, the oxidative burst activity (OBA), phagocytic activity (PA), phagocytic index (PI), and serum antibacterial (SAA) were significantly increased compared to those received bulk vitamins and the control. The activity of antioxidant biomarkers in fish serum including glutathione peroxidase (GPx), catalase (CAT), superoxide dismutase (SOD), total antioxidant capacity (TAC), glutathione reductase (GR), and myeloperoxidase (MPO) showed a rise in the serum of Nile tilapia received nano- and bulk-form of VC and VCE compared to the control and both forms of VE. Furthermore, the level of malondialdehyde (MDA), reduced glutathione (GSH), and oxidized glutathione (GSSG) were significantly increased in the fish serum following the trend of antioxidants enzymes. In conclusion, a dietary nanocomposite of vitamin C and vitamin E enhanced Nile tilapia's growth performance and feed utilization. It could also improve health status and immune response. The values of antioxidant biomarkers indicated that the nanocomposite could help the fish body scavenge the generated reactive oxidative species (ROS).
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Alimentación Animal , Ácido Ascórbico , Cíclidos , Suplementos Dietéticos , Nanocompuestos , Vitamina E , Animales , Nanocompuestos/química , Ácido Ascórbico/farmacología , Ácido Ascórbico/administración & dosificación , Cíclidos/crecimiento & desarrollo , Cíclidos/metabolismo , Cíclidos/sangre , Vitamina E/farmacología , Vitamina E/administración & dosificación , Alimentación Animal/análisis , Antioxidantes/metabolismo , Antioxidantes/administración & dosificación , Antioxidantes/farmacología , Hígado/metabolismo , Hígado/efectos de los fármacosRESUMEN
The transforming growth factor beta-activated kinase 1 (TAK1)/c-Jun N-terminal kinase (JNK) axis is an essential MAPK upstream mediator and regulates immune signaling pathways. However, whether the TAK1/JNK axis harnesses the strength in regulation of signal transduction in early vertebrate adaptive immunity is unclear. In this study, by modeling on Nile tilapia (Oreochromis niloticus), we investigated the potential regulatory function of TAK1/JNK axis on lymphocyte-mediated adaptive immune response. Both OnTAK1 and OnJNK exhibited highly conserved sequences and structures relative to their counterparts in other vertebrates. Their mRNA was widely expressed in the immune-associated tissues, while phosphorylation levels in splenic lymphocytes were significantly enhanced on the 4th day post-infection by Edwardsiella piscicida. In addition, OnTAK1 and OnJNK were significantly up-regulated in transcriptional level after activation of lymphocytes in vitro by phorbol 12-myristate 13-acetate plus ionomycin (P + I) or PHA, accompanied by a predominant increase in phosphorylation level. More importantly, inhibition of OnTAK1 activity by specific inhibitor NG25 led to a significant decrease in the phosphorylation level of OnJNK. Furthermore, blocking the activity of OnJNK with specific inhibitor SP600125 resulted in a marked reduction in the expression of T-cell activation markers including IFN-γ, CD122, IL-2, and CD44 during PHA-induced T-cell activation. In summary, these findings indicated that the conserved TAK1/JNK axis in Nile tilapia was involved in adaptive immune responses by regulating the activation of lymphocytes. This study enriched the current knowledge of adaptive immunity in teleost and provided a new perspective for understanding the regulatory mechanism of fish immunity.
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Inmunidad Adaptativa , Cíclidos , Enfermedades de los Peces , Proteínas de Peces , Activación de Linfocitos , Quinasas Quinasa Quinasa PAM , Animales , Cíclidos/inmunología , Cíclidos/genética , Proteínas de Peces/genética , Proteínas de Peces/inmunología , Enfermedades de los Peces/inmunología , Quinasas Quinasa Quinasa PAM/genética , Quinasas Quinasa Quinasa PAM/inmunología , Infecciones por Enterobacteriaceae/inmunología , Infecciones por Enterobacteriaceae/veterinaria , Edwardsiella/inmunología , Edwardsiella/fisiología , Regulación de la Expresión Génica/inmunología , Transducción de Señal/inmunología , Perfilación de la Expresión Génica/veterinaria , Filogenia , Alineación de Secuencia/veterinaria , Secuencia de AminoácidosRESUMEN
Silver nanoparticles (AgNPs) and Zinc oxide nanoparticles (ZnONPs) have been widely used and are eventually been discharged into the natural aquatic ecosystem. The current study examined and correlated the toxicity of AgNPs and ZnONPs on the Mozambique tilapia, Oreochromis mossambicus. Lethal concentration (LC50) was determined with four different concentrations (0.05, 0.10, 0.15, and 0.20 mg/L) of AgNPs and ZnONPs; subsequently, the fishes were exposed to sublethal concentrations for a period of 21 days, and the oxidative stress and antioxidant and nonantioxidant parameters were studied. Results revealed oxidative stress evinced by increased lipid peroxidation (LPO) protein carbonyl activity (PCA), glutathione-S-transferase (GST), glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT) activity, metallothionein (MT) activity, and reduced glutathione in chronic exposure compared with acute exposure. Nonspecific immunological characteristics such as lysozyme (LYZ), myeloperoxidase (MPO), and respiratory burst activity (RBA) were also noticed in the serum. Furthermore, severe histological damages including damages in telangiectasia and epithelial cell hyperplasia were found in the combined treated group with Ag and ZnONPs than in individual treatments. When Ag and ZnONPs were combined, a reduction in the accumulation of Ag was observed in the liver, which increased drastically in individual exposure. The current findings highlight the importance of taking into account the combined exposure and correlation of NPs, their bioavailability, and toxicity in the aquatic ecosystem.
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BACKGROUND: The inappropriate use of pesticides including fungicides creates severe biological hazards that can endanger fish health and impede sustainable aquaculture. OBJECTIVE: This study investigated the negative impacts of metiram (MET), a fungicide on the health status of Nile tilapia (Oreochromis niloticus) for a 96-hour duration as an acute exposure in a static renewal system. METHODS: Three hundred fish (average body weight: 37.50 ± 0.22 g) were assigned into six groups (50 fish/group) with five replicates (10 fish/replicate). Fish were exposed to various six concentrations (0, 1.5, 3, 4.5, 6, and 7.5 mg/L) of MET as a water exposure to for 96-hour without water exchange. The fish's behavior, clinical signs, and mortalities were documented every day of the exposure period. Additionally, MET's impact on blood profile, stress biomarkers, hepato-renal functions, immune-antioxidant status, and brain biomarker were closely monitored. RESULTS: The lethal concentration (LC50) of MET estimated using Finney's probit technique was 3.77 mg/L. The fish's behavior was severely impacted by acute MET exposure, as clear by an increase in surfacing, loss of equilibrium, unusual swimming, laterality, abnormal movement, and a decline in aggressive behaviors. The survivability and hematological indices (white and red blood cell count, differential white blood cell count, hematocrit value, and hemoglobin) were significantly reduced in a concentration-dependent manner following MET exposure. Acute exposure to MET (1.5-7.5 mg/L) incrementally increased stress biomarkers (nor-epinephrine, cortisol, and glucose), lipid peroxides (malondialdehyde), and brain oxidative DNA damage biomarker (8-hydroxy-2-deoxyguanosine). A hepato-renal dysfunction by MET exposure (4.5-7.5 mg/L) was evidenced by the significant increase in the alanine and aspartate aminotransferases and creatinine values. Moreover, a substantial decline in the immune parameters (lysozyme, complement 3, serum bactericidal activity, and antiprotease activity) and antioxidant variables (total antioxidant capacity, superoxide dismutase, and glutathione peroxidase) resulted from acute MET exposure. CONCLUSION: According to these findings, the 96-hour LC50 of MET in Nile tilapia was 3.77 mg/L. MET exposure triggered toxicity in Nile tilapia, as seen by alterations in fish neuro-behaviors, immune-antioxidant status, hepato-renal functioning, and signifying physiological disturbances. This study emphasizes the potential ecological dangers provoked by MET as an environmental contaminant to aquatic systems. However, the long-term MET exposure is still needed to be investigated.
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Cíclidos , Fungicidas Industriales , Animales , Cíclidos/metabolismo , Cíclidos/fisiología , Fungicidas Industriales/toxicidad , Contaminantes Químicos del Agua/toxicidad , Conducta Animal/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Biomarcadores/sangre , Dosificación Letal Mediana , Encéfalo/metabolismo , Encéfalo/efectos de los fármacosRESUMEN
Type I IFNs are a subset of cytokines exerting their antiviral effects mainly through the JAK-STAT signalling. Immunogenetic studies have shown that fish possess key components of IFN-JAK-STAT cascade, but the information about the distinct responses of STAT1 and STAT2 to different IFNs is rather limited in fish. Here, we identified and cloned STAT1 and STAT2 genes (named as On-STAT1 and On-STAT2) from tilapia, Oreochromis niloticus. On-STAT1 and On-STAT2 genes were detected in all orangs/tissues examined, and were rapidly induced in spleen, head kidney, and liver following the stimulation of poly(I:C). In addition, the stimulation of poly(I:C), poly(A:T), and different subgroups of recombinant IFNs could induce the expression of On-STAT1 and On-STAT2 in TA-02 cells with distinct induction levels. Importantly, On-STAT2 was rapidly phosphorylated by all three subgroups of IFNs, but the phosphorylation of On-STAT1 was only observed in IFNc- and IFNh-treated TA-02 cells, reflecting the distinct activation of STAT by different subgroups of fish IFNs. The present results thus contribute to better understanding of the JAK-STAT signalling mediated by different subgroups of IFNs in fish.
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Proteínas de Peces , Factor de Transcripción STAT1 , Factor de Transcripción STAT2 , Animales , Factor de Transcripción STAT2/genética , Factor de Transcripción STAT2/metabolismo , Proteínas de Peces/genética , Proteínas de Peces/inmunología , Proteínas de Peces/metabolismo , Factor de Transcripción STAT1/genética , Factor de Transcripción STAT1/metabolismo , Fosforilación , Interferón Tipo I/genética , Interferón Tipo I/inmunología , Cíclidos/inmunología , Cíclidos/genética , Secuencia de Aminoácidos , Regulación de la Expresión Génica/inmunología , Regulación de la Expresión Génica/efectos de los fármacos , Filogenia , Poli I-C/farmacología , Alineación de Secuencia/veterinaria , Transducción de Señal/efectos de los fármacosRESUMEN
Tilapia is one of the most important farmed fish in the world and the most cultivated in Brazil. The increase of this farming favors the appearance of diseases, including bacterial diseases. Therefore, the aim of this study was to evaluate the bactericidal activity of copaiba oil, Copaifera duckei, against Streptococcus agalactiae and Flavobacterium columnare and the dietary effect of copaiba oil on zootechnical performance, hematological, biochemical, immunological, and histological analysis before and after an intraperitoneal infection (body cavity) with S. agalactiae in Nile tilapia. For this, fish were randomly distributed into 15 fiber tanks in five treatments (0, 0.25, 0.50, 0.75, and 1.0%) and fed with a commercial diet supplemented with copaiba oil for 30 days. After this period, the fish were randomly redistributed for the experimental challenge with S. agalactiae into six treatments (T0, T1, T2, T3, T4, and T5), the fish were anesthetized, and blood samples were collected to assess hematological, biochemical, immunological, and histological parameters. Copaiba oil showed bactericidal activity against Streptococcus spp. and Flavobacterium spp. in vitro. In addition, concentrations of 0.75 and 1.0% of copaiba oil have an anti-inflammatory effect and improve hematological and immunological parameters, increasing leukocyte numbers, albumin, and serum lytic activity. Furthermore, there is an increase in the intestinal villus length and tissue damage in groups at concentrations of 0.75 and 1.0% of copaiba oil. In conclusion, copaiba oil presented bactericidal activity against Streptococcus spp. and Flavobacterium spp. in vitro, and oral supplementation at concentrations of 0.75 and 1.0% compared to the control group enhanced non-specific immune parameters and digestibility in Nile Tilapia.
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Cíclidos , Suplementos Dietéticos , Enfermedades de los Peces , Flavobacterium , Streptococcus agalactiae , Animales , Streptococcus agalactiae/efectos de los fármacos , Flavobacterium/efectos de los fármacos , Enfermedades de los Peces/microbiología , Enfermedades de los Peces/tratamiento farmacológico , Enfermedades de los Peces/prevención & control , Fabaceae/química , Antibacterianos/farmacología , Infecciones Estreptocócicas/veterinaria , Infecciones Estreptocócicas/tratamiento farmacológico , Infecciones Estreptocócicas/prevención & control , Aceites de Plantas/farmacología , Infecciones por Flavobacteriaceae/veterinaria , Infecciones por Flavobacteriaceae/microbiología , Infecciones por Flavobacteriaceae/tratamiento farmacológico , Infecciones por Flavobacteriaceae/prevención & control , Alimentación Animal , Administración Oral , Acuicultura/métodosRESUMEN
The research examined the impact of an ethanolic extract from the leaves of Kratom (Mitragyna speciosa (Korth.) Havil.) on the growth, antioxidant capacity, immune-related gene expression, and resistance to disease caused by Edwardsiella tarda in Nile tilapia (Oreochromis niloticus). The findings revealed that the extract had the important phytochemical content in the extract included total phenolics content, total flavonoids content, vitamin C, and total antioxidant capacity and 5.42 % of the crude extract was mitragynine. The extract demonstrated antioxidant activity, as evidenced by its IC50 values against ABTS and DPPH radicals and its ferric reducing power in vitro. Moreover, the MIC-IC50 value of 0.625 mg/mL indicated that the growth of the bacteria was reduced by approximately 50 %, and the MBC was 2.50 mg/mL against E. tarda. Furthermore, the orally administered Kratom leaf extract to fingerling tilapia for 8 weeks exhibited a noticeable increase in oxidative stress, as demonstrated by the increase in MDA production in the 10 and 25 g/kg groups. It also exhibited an increase in acetylcholinesterase (AChE) activity in muscle tissue at the 50 g/kg group. However, when administered at a feeding rate of 5-10 g/kg feed, the extract showed an increase in the expression of immune-related genes (IL1, IL6, IL8, NF-kB, IFNγ, TNFα, Mx, CC-chemokine, CD4, TCRß, MHC-IIß, IgM, IgT, IgD) and enhanced resistance to E. tarda infection in fish. Conversely, administering the extract at 25-50 g/kg feed resulted in contrasting effects, suppressing and reducing the observed parameters. Nevertheless, feeding the extract at all concentrations for 8 weeks did not produce any changes in the histology or systemic functioning of the liver and intestines, as indicated by blood biochemistry. These findings suggest that the ethanolic leaf extract from Kratom has the potential to be used as a substitute for antibiotics in the management of bacterial infections in Nile tilapia culture, with a recommended dosage of 5-10 g/kg feed/day for a maximum of 8 weeks.
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Antibacterianos , Antioxidantes , Cíclidos , Edwardsiella tarda , Infecciones por Enterobacteriaceae , Enfermedades de los Peces , Mitragyna , Extractos Vegetales , Hojas de la Planta , Animales , Enfermedades de los Peces/inmunología , Extractos Vegetales/farmacología , Extractos Vegetales/química , Extractos Vegetales/administración & dosificación , Cíclidos/inmunología , Cíclidos/crecimiento & desarrollo , Edwardsiella tarda/efectos de los fármacos , Edwardsiella tarda/fisiología , Infecciones por Enterobacteriaceae/veterinaria , Infecciones por Enterobacteriaceae/inmunología , Antioxidantes/farmacología , Hojas de la Planta/química , Antibacterianos/farmacología , Mitragyna/química , Resistencia a la Enfermedad/efectos de los fármacos , Dieta/veterinaria , Alimentación Animal/análisis , Suplementos Dietéticos/análisisRESUMEN
The aim of this research was to estimate the immunopotentiation effect of brown algae Padina boergesenii water extract on Nile tilapia, Oreochromis niloticus through resistance to Pseudomonas putida infection. Gas Chromatography Mass Spectrometry was utilized to characterize the seaweed phytoconstituents. One hundred and twenty-six fish were divided in triplicates into two equal groups corresponding to two diet variants that used to feed Nile tilapia for 20 successive days: a basal (control), and P. boergesenii water extract supplemented group. Fish samples were collected at 10-days intervals throughout the experiment. Serum biochemical constituents, total antioxidant capacity (TAC), and some immune related genes expression of the spleen and intestinal tissues of experimental fish were studied, as well as histological examination of fish immune tissues. Moreover, following 20 days of feeding, the susceptibility of Nile tilapia to P. putida infection was evaluated to assess the protective effect of the used extract. The findings indicated that the studied parameters were significantly increased, and the best immune response profiles were observed in fish fed P. boergesenii water extract for 20 successive days. A bacterial challenge experiment using P. putida resulted in higher survival within the supplemented fish group than the control. Thus, the lowered post-challenge mortality of the fish may be related to the protection provided by the stimulation of the innate immune system, reduced oxidative stress by higher activity of TAC, and elevated levels of expression of iterleukin-1beta (IL-1ß), beta-defensin (ß-defensin), and natural killer-lysin (NKl). Moreover, the constituents of the extract used showed potential protective activity for histological features of the supplemented fish group when compared to the control. Collectively, this study presents a great insight on the protective role of P. boergesenii water extract as an additive in Nile tilapia feed which suggests its potential for improving the immune response against P. putida infection.
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Alimentación Animal , Cíclidos , Suplementos Dietéticos , Enfermedades de los Peces , Infecciones por Pseudomonas , Pseudomonas putida , Animales , Pseudomonas putida/efectos de los fármacos , Enfermedades de los Peces/microbiología , Enfermedades de los Peces/prevención & control , Alimentación Animal/análisis , Infecciones por Pseudomonas/veterinaria , Infecciones por Pseudomonas/tratamiento farmacológico , Phaeophyceae/química , Dieta/veterinaria , Resistencia a la Enfermedad/efectos de los fármacos , Extractos Vegetales/farmacología , Extractos Vegetales/química , Extractos Vegetales/administración & dosificaciónRESUMEN
Yeasts are unicellular eukaryotic microorganisms extensively employed in various applications, notably as an alternative source of protein in feeds, owing to their nutritional benefits. Despite their potential, marine and mangrove yeast species used in the aquaculture industry have received little attention in the Philippines. Pichia kudriavzevii (A2B R1 ISO 3), sourced from bark samples, was selected and mass-produced due to its high protein content and amino acid profile. The dried biomass of P. kudriavzevii was incorporated into the diets of Nile tilapia (Oreochromis niloticus) juveniles at varying inclusion levels (0, 1, 2, and 4 g/kg diet) and its effect on their growth performance, body composition, and liver and intestinal morphology was assessed after 40 days of feeding. The groups that received P. kudriavzevii at a concentration of 2 g/kg diet exhibited higher final body weight, percent weight gain, and specific growth rate in comparison to the other treatment groups. Whole body proximate composition did not vary among the dietary groups. Intestinal and liver histopathology also indicated no abnormalities. These findings suggest the potential of ascomycetous P. kudriavzevii as a beneficial feed additive in Nile tilapia diets, warranting further investigation into its long-term effects and broader applications in fish culture.
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Alimentación Animal , Acuicultura , Cíclidos , Pichia , Animales , Alimentación Animal/análisis , Cíclidos/crecimiento & desarrollo , Cíclidos/microbiología , Pichia/crecimiento & desarrollo , Pichia/aislamiento & purificación , Pichia/metabolismo , Dieta/veterinaria , Hígado/microbiología , Intestinos/microbiología , Suplementos Dietéticos/análisis , FilipinasRESUMEN
Monitoring heavy metal accumulation is essential for assessing the viability of aquatic ecosystems. Our methodology involved integrating analysis of immunological, stress, inflammatory, and growth-related gene expression in male and female Nile tilapia with on-site recordings of physicochemical parameters. Additionally, we assessed the effect of different physicochemical parameters on heavy metal bioavailability and residual concentration in fish and water. Samples of fish and water were gathered from three different localities: Lake Brullus, a brackish lake sited in northern Egypt; Lake Nasser, an artificial freshwater reservoir located in southern Egypt; and El-Qanater El-Khayria, a middle-freshwater location belonging to the Rashid branch of the river Nile. The assessment of heavy metal residues (Fe, Cu, Zn, Mn, and Ni) revealed that their concentrations were higher in fish specimens compared to their counterparts in water (except for Ni). In addition, Lake Brullus emerges as the most polluted area, exhibiting elevated levels of heavy metals concentrations in water and fish specimens. In contrast, Lake Nasser showed the least degree of heavy metals pollution. Gene expression analysis revealed gender-specific responses to heavy metal exposure at the three investigated water bodies. The expression of hepatic antioxidant genes (GST and MT) and inflammatory-related genes (CC-chemokine and TNFα) increased in males compared to females. In females, the immune and pro-inflammatory-related genes (IgM and CXC2-chemokine) transcripts were upregulated. Additionally, growth-related genes were downregulated in both Lake Brullus and El-Qanater; on the contrary, fish samples from Lake Nasser exhibited a normal expression pattern of growth-related genes. Stress-related genes (HSP70 and HSP27) showed significant downregulation in gills of both genders from Lake Brullus. The minimal presence of heavy metal contaminants in Lake Nasser seems to endorse the normal patterns of gene expression across all gene categories. A potential gender-specific gene expression response towards pollution was noticed in genes associated with inflammation and antioxidant activities. This highlights the importance of considering gender-related responses in future environmental assessments.
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Cíclidos , Ecosistema , Metales Pesados , Contaminantes Químicos del Agua , Animales , Cíclidos/genética , Cíclidos/metabolismo , Femenino , Masculino , Metales Pesados/análisis , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/toxicidad , Lagos , Regulación de la Expresión Génica/efectos de los fármacos , Egipto , Factores Sexuales , Monitoreo del Ambiente/métodosRESUMEN
The present study was conducted to evaluate the effects of exposure to sublethal concentrations of cypermethrin on growth, phenotypic traits, and metabolic and antioxidant enzymes activities of monosex tilapia (Oreochromis niloticus). The median lethal concentration (LC50) of cypermethrin was initially ascertained to be 0.04 ppm after 12 h of exposure to three concentrations (0.04, 0.20, and 1.0 ppm) via the Probit analysis method. The sublethal exposures were obtained for 3 months at 0.0016, 0.008, and 0.04 ppm of cypermethrin. The growth performance, phenotypic traits, and enzymatic activity were analyzed. The research findings revealed a notable impact of cypermethrin on the growth performance of monosex tilapia, with a significant (p < 0.05) decrease in weight observed as the concentration increased. The experiment documented a significant change (p < 0.05) in the phenotypic traits of standard length, total length, tail length, trunk length, eye diameter, body area, and color patterns, but not dressing percentage. Furthermore, it was observed that the activities of amylase and protease in both the intestine and muscle decreased significantly (p < 0.05) with increasing concentrations of cypermethrin, except for amylase in the muscle, where no significant change was noted (p > 0.05). The results also demonstrated significant reductions (p < 0.05) in the activity of metabolic enzymes, specifically superoxide dismutase and catalase, following exposure to sublethal levels of cypermethrin. The study suggested that sublethal exposure of pyrethroid alters the growth, phenotypic traits, metabolic enzymes activities, and immunity of monosex tilapia.
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Cichlid fishes of the genus Oreochromis (tilapia) are among the most important fish for inland capture fisheries and global aquaculture. Deliberate introductions of non-native species for fisheries improvement and accidental escapees from farms have resulted in admixture with indigenous species. Such hybridization may be detrimental to native biodiversity, potentially leading to genomic homogenization of populations and the loss of important genetic material associated with local adaptation. By contrast, introgression may fuel diversification when combined with ecological opportunity, by supplying novel genetic combinations. To date, the role of introgression in the evolutionary history of tilapia has not been explored. Here we studied both ancient and recent hybridization in tilapia, using whole genome resequencing of 575 individuals from 23 species. We focused on Tanzania, a natural hotspot of tilapia diversity, and a country where hybridization between exotic and native species in the natural environment has been previously reported. We reconstruct the first genome-scale phylogeny of the genus and reveal prevalent ancient gene flow across the Oreochromis phylogeny. This has likely resulted in the hybrid speciation of one species, O. chungruruensis. We identify multiple cases of recent hybridization between native and introduced species in the wild, linked to the use of non-native species in both capture fisheries improvement and aquaculture. This has potential implications for both conservation of wild populations and the development of the global tilapia aquaculture industry.
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Hibridación Genética , Filogenia , Animales , Tanzanía , Flujo Génico , Cíclidos/genética , Tilapia/genéticaRESUMEN
The Nile Tilapia (Oreochromis niloticus), a gonochoristic teleost fish with a XX/XY sex-determination system, is an ideal model for investigating gonadal sex differentiation. During gonadal differentiation, the expression of cyp19a1a in XX gonads and dmrt1 in XY gonads are required for undifferentiated tissues to develop into ovary or testis. In this study, quantitative real-time RT-PCR assessed the expression of cyp19a1a and dmrt1 genes in gonads and tail fin tissues. Differences in gene expression mean among sexually differentiated fish were analyzed using two-way analysis of variance (ANOVA) and validation of mixed model using discriminant analysis (DA) for morphometric traits and the gene expression in gonads and tail fin tissues used to validate and utilize them in discriminating sexes in sex-differentiated Nile Tilapia fish. The results revealed that, cyp19a1a gene expression in female ovaries was more significant than dmrt1 in male testis. In the other hand, the dmrt1 gene expression in the tail fin was higher in males than females. Both, cyp19a1a and dmrt1 genes, can discriminate fish sexes by 100% by using their expression in tail fin tissues. In conclusion, the cyp19a1a and dmrt1 genes could be used as a genetic marker to discriminate between the Nile Tilapia sexes, whereas used as an indicator for ovarian or testis differentiation in sexually differentiated Nile Tilapia using tail fin tissues. It is worth mentioning that this is the first investigation for using cyp19a1a and dmrt1 genes from Nile Tilapia tail fin tissues in sex determination.
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Elongation of very long-chain fatty acids protein 6 (ELOVL6) plays a pivotal role in the synthesis of endogenous fatty acids, influencing energy balance and metabolic diseases. The primary objective of this study was to discover the molecular attributes and regulatory roles of ELOVL6 in male Nile tilapia, Oreochromis niloticus. The full-length cDNA of elovl6 was cloned from male Nile tilapia, and was determined to be 2255-bp long, including a 5'-untranslated region of 193 bp, a 3'-untranslated region of 1252 bp, and an open reading frame of 810 bp encoding 269 amino acids. The putative protein had typical features of ELOVL proteins. The transcript levels of elovl6 differed among various tissues and among fish fed with different dietary lipid sources. Knockdown of elovl6 in Nile tilapia using antisense RNA technology resulted in significant alterations in hepatic morphology, long-chain fatty acid synthesis, and fatty acid oxidation, and led to increased fat deposition in the liver and disrupted glucose/lipid metabolism. A comparative transcriptomic analysis (elovl6 knockdown vs. the negative control) identified 5877 differentially expressed genes with significant involvement in key signaling pathways including the peroxisome proliferator-activated receptor signaling pathway, fatty acid degradation, glycolysis/gluconeogenesis, and the insulin signaling pathway, all of which are crucial for lipid and glucose metabolism. qRT-PCR analyses verified the transcript levels of 13 differentially expressed genes within these pathways. Our findings indicate that elovl6 knockdown in male tilapia impedes oleic acid synthesis, culminating in aberrant nutrient metabolism.
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Cíclidos , Elongasas de Ácidos Grasos , Animales , Masculino , Elongasas de Ácidos Grasos/genética , Elongasas de Ácidos Grasos/metabolismo , Cíclidos/genética , Cíclidos/metabolismo , Metabolismo de los Lípidos/genética , Silenciador del Gen , Hígado/metabolismo , Nutrientes/metabolismo , Ácidos Grasos/metabolismo , Regulación de la Expresión Génica , Secuencia de Aminoácidos , Clonación Molecular , Acetiltransferasas/genética , Acetiltransferasas/metabolismo , Técnicas de Silenciamiento del GenRESUMEN
Temperature is one of the most important non-genetic sex differentiation factors for fish. The technique of high temperature-induced sex reversal is commonly used in Nile tilapia (Oreochromis niloticus) culture, although the molecular regulatory mechanisms involved in this process remain unclear. The brain is an essential organ for the regulation of neural signals involved in germ cell differentiation and gonad development. To investigate the regulatory roles of miRNAs-mRNAs in the conversion of female to male Nile tilapia gender under high-temperature stress, we compared RNA-Seq data from brain tissues between a control group (28 °C) and a high temperature-treated group (36 °C). The result showed that a total of 123,432,984 miRNA valid reads, 288,202,524 mRNA clean reads, 1128 miRNAs, and 32,918 mRNAs were obtained. Among them, there were 222 significant differentially expressed miRNAs (DE miRNAs) and 810 differentially expressed mRNAs (DE mRNAs) between the two groups. Eight DE miRNAs and eight DE mRNAs were randomly selected, and their expression patterns were validated by qRT-PCR. The miRNA-mRNA co-expression network demonstrated that 40 DE miRNAs targeted 136 protein-coding genes. Functional enrichment analysis demonstrated that these genes were involved in several gonadal differentiation pathways, including the oocyte meiosis signaling pathway, progesterone-mediated oocyte maturation signaling pathway, cell cycle signaling pathway and GnRH signaling pathway. Then, an interaction network was constructed for 8 miRNAs (mir-137-5p, let-7d, mir-1388-5p, mir-124-4-5p, mir-1306, mir-99, mir-130b and mir-21) and 10 mRNAs (smc1al, itpr2, mapk1, ints8, cpeb1b, bub1, fbxo5, mmp14b, cdk1 and hrasb) involved in the oocyte meiosis signaling pathway. These findings provide novel information about the mechanisms underlying miRNA-mediated sex reversal in female Nile tilapia.