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Tilapia is a kind of fish with a huge amount of aquaculture, and a lot of byproducts are wasted in processing. Of these, fish skin is the most valued due to its high content of gelatin, which has good characteristics such as low hypoallergenic, biocompatibility, and permeability. In this study, a novel pentapeptide (Leu‐Ser‐Gly‐Tyr‐Gly, LYG) was isolated from gelatin gastrointestinal digests of tilapia skin and verified the anti‐inflammatory and antiangiogenic activity of LYG, which can inhibit scar formation. In addition, the active sites were analyzed using molecular docking. The key active amino acids Leu and Tyr of LYG were able to form hydrogen bonds and good hydrophobic structures with transforming growth factor β1 (TGF‐β1). Hyperplastic scar (HS) is a common fibrous proliferative disorder of the skin, and fibrosis is the process of scar formation. It is well known that the inhibition of collagen and angiogenesis is an effective way to combat HS. The results of this study show that LYG inhibited collagen synthesis and inflammatory stress in mouse fibroblasts (L929), suppressed the angiogenic signaling pathway in vascular endothelial cells (HUVECs), and reduced scar formation after wound healing in mice. This study provides new ideas for improving the diversified use of tilapia resources. [ABSTRACT FROM AUTHOR]

A 50‐day test was adopted to compare the growth performance, liver histology, glucose metabolism, lipid (L) metabolism, ion transport, and ammonia metabolism of tilapia fed different carbohydrate–lipid (C:L) ratio diets under saline–alkaline water (salinity = 16 mmol/L and alkalinity = 35 mmol/L). The C and L levels of five isoenergetic (16.5 kJ/g) and isonitrogenous (32% protein) diets were C45%:L3% (L3), C38%:L6% (L6), C31%:L9% (L9), C24%:L12% (L12), and C17%:L15% (L15). This study found that the dietary C:L ratio did not affect the survival rate (SR), feed conversion ratio (FCR), or condition factor of tilapia in saline–alkali water, but fish in the L12 group had the highest weight gain (WG) rate and the lowest hepatosomatic index (HSI) compared with the other groups. Fish fed the higher C diet (L3 and L6) had a higher ion transport capacity and ammonia excretion capacity in gills. However, the highest mRNA expression of genes involved in glutamine metabolism and urea metabolism in the liver was found in the high‐L diet groups (L12 and L15). In particular, a lower serum ammonia concentration was observed in the high‐L diet groups (L12 and L15). In addition, biochemical indicators indicated that the L12 group had the highest liver pyruvic acid, lactic dehydrogenase (LDH), and lipase (LPS) and serum total cholesterol (T‐CHO) contents. In summary, this study indicated that dietary Ls could promote glutamine metabolism and urea metabolism more than dietary Cs and then reduce the serum ammonia concentration of tilapia in saline–alkali water. A dietary C:L ratio of 2:1 was beneficial to the growth and ammonia excretion of tilapia in saline–alkali water in this study. [ABSTRACT FROM AUTHOR]

Aquaculture contributes to agricultural development, economic growth, and poverty reduction initiatives in Zambia. In northern and rural regions of the country, development requires improvements to the management of local and farm-generated inputs. Fish farmers have limited market access and purchasing power, which restricts access to commercial inputs, such as formulated feeds and chemical fertilizers. Instead, farmers adopt integrated-agriculture-aquaculture (IAA) practices, whereby on-farm resources supply essential inputs. Research is limited regarding local systems of resource management, and this hinders development of innovations for improving efficiency. This mixed-methods study explored local patterns of resource utilization. Smallholders (n = 63) participated in surveys and interviews regarding resource management. A series of quantitative analyses, including descriptive statistics, principal component analyses (PCA), and multinomial logistic regression (logit) models, identified relationships between these resources, household livelihood, and system productivity. Qualitative analyses explored farmer perceptions regarding seasonal resource availability. Results suggested that livestock manure, homemade feeds comprising maize and soybean, garden residues, and kitchen wastes were the most frequently selected inputs. Logit models of feeding intensity found that income, proximity to Luwingu Town, experience in aquaculture, and access to extension services were key household resources. High-intensity feeding strategies incorporated commercial feeds, chemical fertilizers, as well as home-made feeds containing a wide diversity of both high- and low-quality ingredients. Low-intensity feeding strategies incorporated only farm waste and termites. Potential innovations that may improve system performance in resource poor contexts are considered and recommendations for additional research are offered. [ABSTRACT FROM AUTHOR]

Recent research has looked at various macroalgae species as dietary components or feed additives for a variety of fish species due to their nutritional value. The objective of this study was to examine the impact of Najas indica, a macroalgae extract, on the growth performance, proximate composition, and metabolic activities of monosex tilapia (Oreochromis niloticus), while also isolating the compounds present. Three distinct solvents (n‐hexane, ethyl acetate, and ethanol) were used to extract bioactive compounds from a coarse powder of macroalgae after drying and grinding, and gas chromatography–mass spectrometry (GC–MS) analysis was used to detect bioactive compounds. The extracts were combined with commercial feed (0.4%) and applied to the treatment with three replications and a control containing 50 fingerlings per tank for 5 weeks. The findings indicated a significant increase in the final weight, weight gain, specific growth rate (SGR), and survival rate among the treated fish, whereas the feed conversion ratio (FCR) was observed to decrease in comparison to the control group. Significantly higher levels of protein and lipids were found in treated fish, whereas moisture and ash levels were significantly lower compared to control fish. In treated fish, the digestive enzyme amylase was significantly higher, but the protease enzyme reduced significantly. The antioxidant enzyme superoxide dismutase activity (SOD) was significantly higher in the treatment group, whereas the catalase (CAT) enzyme did not differ significantly. A total of 47 bioactive compounds were identified in N. indica, among which the prominent compounds included n‐hexadecanoic acid, neophytadiene, phytyl palmitate, d‐mannitol, and heptanoic acid. The results obtained from this study indicate that the utilization of N. indica macroalgae extract has the potential to serve as an additional dietary component, therefore, enhancing the growth performance and metabolic functions of fish. [ABSTRACT FROM AUTHOR]

Background: Tilapia (Oreochromis niloticus) is the most widely cultured freshwater fish species in Bangladesh and worldwide. However, commercial tilapia culture systems face increasing challenges from bacterial infections. Objectives: The objective of this study was to identify the bacterial isolates from infected tilapia in an intensive cage culture farm located along the Shitalakshya River in Bangladesh. Methods: Infected fish samples were collected and underwent comprehensive clinical and post‐mortem investigations, followed by phenotypic, biochemical and molecular identification of the bacterial isolates, as well as histopathological and antibiotic susceptibility examinations. Results: Phenotypic and biochemical characterization showed similarities of the ‐collected isolates with Aeromonas veronii. Moreover, molecular analysis of the bacterial conserved region 16S rRNA also confirmed these isolates as A. veronii. The analysed 16S rRNA sequence (GenBank accession no. PP832815) showed a close relationship (100% identity) with A. veronii from China (GenBank accession no. MT071624) in the NCBI BLAST search, and in the phylogenetic tree, they grouped in a single clade. This close genetic relationship is also supported by the low genetic distance between the isolates. Histopathological analysis revealed gross pathological changes like necrosis, hypertrophy and inflammation in muscle tissues. The isolates were found to be sensitive to multiple antibiotics but resistant to trimethoprim and sulphamethoxazole. Conclusion: This study investigated the presence of A. veronii infection in tilapia (O. niloticus) in an intensive cage culture farm in Bangladesh. [ABSTRACT FROM AUTHOR]

Simvastatin (SIM), a commonly prescribed drug for lowering serum-lipid, has been detected in many aquatic environments. Exposure to high concentrations of SIM in rats and aquatic organisms resulted in toxicity to hepatocytes and negative effects on development. However, there is a paucity of studies on the effects of long-term exposure to low concentrations of SIM on aquaculture species. This study aimed to analyze the effects of environmentally relevant concentrations (0.1 µg/L and 1 µg/L) of SIM exposure for two months on developing Mozambique tilapias. Surprisingly, the growth of male tilapias was enhanced after a 2-month SIM exposure. The analysis of testis histology revealed that after the SIM exposure, the development of the testis was delayed, and sperm production was reduced. Sequencing of testis transcriptomes showed that the exposure to SIM altered the expression of many genes related to the development of testes and spermatogenesis. These data suggest that a 2-month exposure to environmentally relevant concentrations of increases the growth of male tilapias by inhibiting sexual development of males. [ABSTRACT FROM AUTHOR]

Feed-based bivalent vaccine (FBBV) containing killed whole organism (KWO) of Streptococcus agalactiae and Aeromonas hydrophila with 10% palm oil was previously proved to improve red hybrid tilapia’s (Oreochromis sp.) immunity against streptococcosis and Aeromonas infections. This study characterized the FBBV’s stability following the preparatory process and storage. The FBBV was prepared, and the KWO’s stability was determined microscopically and molecularly. The efficacy of FBBV stored at room temperature (25 ± 2 °C) for 0, 30 and 60 days was investigated in red hybrid tilapia. The results indicated the addition of palm oil was not affecting the KWO’s structure and helping in the FBBV’s pelletization. In 1 g of FBBV contained 1.5 × 109 CFU/g of S. agalactiae and 4.9 × 109 CFU/g of A. hydrophila, respectively, even after 60 days of storage at room temperature. The KWO’s structure in FBBV was not affected following in vitro acidic tolerance analysis, as noted from light and electron microscopies. The FBBV’s carbohydrate, energy, moisture, total protein and total ash contents remained stable at 95% after 60 days of storage at room temperature, while the KWO’s concentration was slightly reduced to 83.3% for S. agalactiae (1.25 × 109 CFU/g) and 80.6% for A. hydrophila (3.85 × 109 CFU/g), respectively. Fish vaccinated with FBBV that was stored for 0, 30 and 60 days did not show any significant differences (p ≥ 0.05) in the relative percent survival when challenged with pathogenic Streptococcus spp. and Aeromonas spp. These findings suggested that the FBBV is a stable vaccine, which underscores its potential application as aquatic vaccines in aquaculture. [ABSTRACT FROM AUTHOR]

The Strep Easy Kit, a bio‐enrichment dual ICG‐strip test, is a diagnostic tool designed for the detection of Streptococcus agalactiae, an important pathogenic bacterium in tilapia farming. The kit can simultaneously identify two different serotypes of S. agalactiae, serotype Ia and serotype III. This capability is crucial for the collection of valuable epidemiological data and facilitates strategic planning for effective vaccine development and deployment. The Strep Easy Kit consists of two main steps: pathogen enrichment and pathogen detection. The enrichment step increases the concentration of bacteria so that the bacterial load is raised to the level reliably detectable by the subsequent ICG strip test. This is achieved by incubating the fish samples in a suitable liquid medium under specified temperature and time conditions. The second step involves the use of the dual‐ICG strip test. This strip test consists of two monoclonal antibodies and one polyclonal antibody that are specific to S. agalactiae and can distinguish between S. agalactiae serotype Ia and S. agalactiae serotype III. This dual capability enables the ICG strip test to simultaneously detect both serotypes of S. agalactiae in a single test kit. The detection limit of the test kit, which consists of a dual ICG‐Strip test combined with an enrichment step, is 100 CFU/mL. The kit can be used to detect S. agalactiae in both live and dead fish samples, making it versatile for various testing scenarios. The test results obtained using the Strep Easy Kit have shown a 94.4% correlation with the standard method (Thai Agricultural Standard; TAS 10453‐2010), with 90.2% sensitivity and 100% specificity. Significant advantages of the Strep Easy Kit lie in its simplicity and portability, allowing farmers to perform the test by themselves and on‐site. This makes it a practical and accessible tool for the tilapia farming industry. [ABSTRACT FROM AUTHOR]

Tilapia is a model fish species used as a pollution biomonitor due to its tolerance and availability in many contaminated sites. Blue tilapia Oreochromis aureus specimens (n = 320) were collected in eleven dams influenced by mining in the SE Gulf of California region (dams 1, 2 and, 3 comprise 55 mining sites; dam 4 comprises 8; dams 6, 8, 10, and 11, ≤ 6; and dams 5, 7, and 9 include 19, 20, and 16 mining sites, respectively). Cadmium, Cu, Pb, and Zn concentrations were analyzed in the muscle, liver, gills, and guts to identify metal pollution and evaluate risks and seasonal changes. The distinct tissues exhibited different metal accumulation capacities, therefore allowed develop a diagnosis comparative between the eleven dams. In general, metal concentrations were higher in dams 1, 2, 5, and 9, which are associated with more mining sites in their sub-basins. The four metals exhibited the highest levels in the tilapia liver in dams 1 and 2, which can be related to the present and past mining activity in the lower watershed (55 sites) and the geothermal activity in these dams. In general, Zn exhibited the highest level in the tilapia livers from dams 1, 2, 3, 4, 5, and 10 compared to the maximum mean (220 µg/g) concentrations previously recorded. The non-carcinogenic risks indicated that the Pb risk was enhanced when the intake was ≥ 231.5 g week−1 of tilapia muscle, indicating a potential risk of adverse health effects for the entire population. [ABSTRACT FROM AUTHOR]

The cold stress during overwintering is considered the bottleneck of red tilapia industry. In this study, the water temperature (WT) was reduced by 2 °C per day from 20 °C to 8 °C in the cold (C) group. Then transcriptome of brain(B), gill(G), liver(L) and skin(S) tissues and proteome of G, L and S tissues were performed in C and Normal (N) (WT: 20 °C) group. 24 transcriptomes were completed, and 168.8 Gb data were obtained, with more than 5.89 Gb clean data of each sample. A total of 30499 annotation results were obtained with 3199, 4697, 4393, and 3382 differentially expressed mRNAs in NB_vs_CB, NG_vs_CG, NL_vs_CL, NS_vs_CS. 18 DIA proteomes were performed, and 6341 proteins were obtained with 178, 500 and 166 differentially expressed proteins in NG_vs_CG, NL_vs_CL, NS_vs_CS. Our datasets can be reused for key genes and proteins identification, omics joint analysis and regulatory mechanism analysis of low temperature or cold stress in fish, which will help understanding the regulatory mechanism and facilitate the molecular selective breeding of cold-resistant varieties of fish. [ABSTRACT FROM AUTHOR]

Sex identification and the selection of monosex male tilapia are crucial for tilapia aquaculture. In this study, we evaluated the application of ultrasonography as an alternative procedure for sex identification and reproductive assessment in Nile tilapia (Oreochromis niloticus). Ultrasonography was performed on 23 fish weighing 232-1,281 g to capture longitudinal and transverse images of the ovaries and testes. Female tilapia were identified by the presence of numerous small egg granules and gray or light gray ovarian tissue and male tilapia by the homogeneous echogenicity and uniform gray tubular appearance of the testes. These distinct echogenic patterns allowed for accurate differentiation between the female and male fish. Ultrasonography achieved a 95% accuracy in sex identification, with minimal stress to the fish during the procedure, compared to manual sex sorting, which demonstrated an accuracy of 87%. Furthermore, the method facilitated the assessment of the reproductive status of the fish, including the maturation stages and fecundity potential. The use of ultrasonography offers significant advantages over traditional methods, such as animal welfare enhancements and improved breeding program efficiency. Our findings support the integration of ultrasonography into aquaculture practices and will promote sustainable and humane fish farming while optimizing reproductive management and productivity. [ABSTRACT FROM AUTHOR]

ABSTRACT Recent years have witnessed a remarkable global surge in fish production, with Nile tilapia (Oreochromis niloticus) emerging as a prominent contributor owing to its high demand as a nutritious food source. However, unlike terrestrial species, maintaining genealogical control and collecting phenotypic data in fish farming poses significant challenges, necessitating advancements to support genetic improvement programmes. While conventional methods, such as body measurements using rulers and photographs are prevalent in data collection, the potential of ultrasound—a less invasive and efficient tool for fish measurement—remains underexplored. This study assesses the viability of ultrasonography for genetically selecting carcass characteristics in Nile tilapia. The investigation encompasses data from 897 animals representing 53 full‐sib tilapia families maintained in the genetic improvement programme at the Federal University of Lavras. To measure carcass traits, the animals were sedated with benzocaine and ultrasound images were obtained at three distinct points. Subsequently, the animals were euthanised through medullary sectioning for further carcass processing. After evisceration, filleting and skinning, all weights were meticulously recorded. (Co)variance components and genetic parameters of the measured traits were estimated using the Bayesian approach by Gibbs sampling implemented in MTGSAM (Multiple Trait Gibbs Sampling in Animal Models) software. Heritabilities estimated for the studied carcass traits were moderate, ranging from 0.23 to 0.33. Notably, phenotypes derived from ultrasound images demonstrated substantial genetic correlations with fillet yield (0.83–0.92). In conclusion, this study confirms that indirect selection based on ultrasound images is effective and holds promise for integration into tilapia breeding programmes aimed at enhancing carcass yield. [ABSTRACT FROM AUTHOR]

Rationing aquaculture farming feed is challenging for producers due to high feed costs, representing 30%–60% of the total operating costs. Therefore, optimal timing of feeding could lead to improved economic returns from an aquatic system. An optimal dynamic feeding model has been determined considering the von Bertalanffy growth model. A bioeconomic model of tilapia production in Mexico for specific markets was used for numerical illustration. The von Bertalanffy growth model was parameterized with experimental data from tilapia (Oreochromis niloticus) fed four ration sizes (50%, 80%, 100%, and satiety), in order to determine different optimal rationing for different fish sizes (200, 300, and 400 g), market prices (Monterrey, Cancún, Mexico City, and On site), and optimal harvesting times (OHT), considering the time value of money. The results of the modeled optimal feeding trajectories show a continuous decrease from stocking to reach a minimum value and then slightly approaching the harvest size. This result contrasts with the recommendations of the feed suppliers and with those found when a potential growth model was used. The results in the case study showed that the Monterrey market presented the highest present value of the benefits in the OHT and the different market sizes. The implications of the Bertalanffy model for optimal rationing trajectories are presented in the discussion. [ABSTRACT FROM AUTHOR]

This study aimed to conduct a multidisciplinary investigation integrating detailed morphology, molecular characterization, water parameters, histopathology alteration, and the trials of treatment of Clinostomum spp. In this study, 300 Nile tilapia (Oreochromis niloticus) were collected from the farmed and wild Nile River at Al Bahr Al Aazam, Giza Governorate to assess Clinostomid infection prevalence. Fish and water samples were collected from private fish farms, and water drains at Dakahlia, and Giza, Egypt. Analysis of the water revealed inadequate water quality, particularly in the fish farms. Snails and piscivorous birds were abundant at fish collection sites. The recovered Clinostomid MCs morphological characteristics and COI gene sequence analysis identified them as Clinostomum complanatum, C. phalacrocoracis, and Euclinostomum heterostomum. Clinostomid MCs disturbed the fish's hematological and biochemical blood parameters. Bath treatment of parasitized fish with praziquantel (2 mg/L for 24 h) revealed a significant reduction in the number of vital MCs vs. infected fish (non-treated). Praziquantel (PZQ) is an effective and safe therapy for controlling Clinostomid infections affecting farmed Nile tilapia. The current findings indicate a link between poor environmental conditions and Clinostomum infections in tilapia. The study highlights the impacts of Clinostomid MCs on fish health and recommends bath treatment with PZQ as an efficient control method for these dangerous parasites to protect human and fish health. [ABSTRACT FROM AUTHOR]

This 12-week study evaluated the impact of krill meal (KM) in Nile tilapia, Oreochromis niloticus, reproductive performance. Two test feeds with 2% and 5% KM were compared to a commercial tilapia broodstock feed. Fish were stocked in 12 hapas with 50 females and 16 males each, allowing four replicate hapas per dietary treatment. Egg production exhibited a general decline. The control group yielded 16,066 ± 6,124 eggs per hapa, while the 2% KM diet showed an 18% increase (18,976 ± 6,417 eggs), and the 5% KM diet exhibited a 30% increase (20,947 ± 7,029 eggs). However, no statistically significant differences were observed in egg production. Spawning females declined over time, with 5% KM showing a 29% increase, but no statistical differences could be detected among dietary treatments. Egg hatching rates remained consistent, but the 5% KM diet hinted at a positive trend with 10% more larvae at day 10 despite the lack of statistical differences. Females fed KM spawned more frequently, and the 5% KM diet influenced higher fat content and elevated levels of omega-3 in Nile tilapia eggs. Overall, the study suggests positive effects on reproductive performance and larval survival in Nile tilapia with inclusion of krill meal in their diets. [ABSTRACT FROM AUTHOR]

Microalgae are promising as prebiotics in aquaculture. Arthrospira maxima has potential nutritional value but is poorly studied. We assessed A. maxima feed supplementation in tilapia fry and evaluated its effect on growth performance and gut microbiota. Fish were cultivated in ponds under 0%, 5%, 10%, and 15% A. maxima inclusion treatments. Growth parameters and biomass proximate analysis were assessed. A meta-amplicon analysis was performed on the gut microbiota using DADA2 and PICRUST2 for functional prediction. Among treatments, the 5% supplementation group seemed to present no negative effect on growth parameters and did not compromise the nutritional quality of tilapia fry biomass. Microbial composition was characterized by Cetobacterium, Pseudomonas and Aeromonas genera, and a predominance of beneficial metabolic pathways. Microbiota of tilapia fry fed with A. maxima showed unique genera with reported beneficial functions in tilapia. The abundance of potential pathogenic taxa was significantly decreased in supplementation treatments, possibly related to valuable compounds of A. maxima. The inclusion of the microalgae supported the stability of the microbiota, favoring the growth of commensal species. This seems to have an effect on decreasing the presence of pathogenic genera in the gastrointestinal tract. Overall, our work proposes 5% feed inclusion of A. maxima to be the most suitable for tilapia fry aquaculture to maintain production rates while improving general health. [ABSTRACT FROM AUTHOR]

Aquaculture is a crucial and rapidly expanding industry in global food production. Fisheries are also an essential socio-economic activity, providing abundant resources and remarkable prospects. However, due to the deteriorating ecological environment, aquatic animals are often exposed to traumatic conditions and are susceptible to bacterial infections that pose significant challenges for aquaculture production. The indiscriminate use of antibiotics in the past has led to the emergence of multidrug-resistant pathogens and sudden outbreaks of infectious diseases, resulting in serious economic losses. Moreover, the use of expensive chemotherapeutic drugs and antibiotics has negative impacts on aquatic environments. Therefore, it is increasingly important to adopt alternative natural agents, such as probiotics and their metabolites, to enhance healthy fish production. Probiotics are microorganisms that have numerous beneficial effects on their hosts. They are environmentally friendly, non-toxic, and cost-effective. This review specifically focuses on the use of Bacillus sp. as probiotics to promote healthy tilapia production in the aquatic sector, while also examining their interactions with the immune system and gut micro-biota. The information presented in this review can guide future research and promote effective and healthy tilapia culture production. [ABSTRACT FROM AUTHOR]

In this study, we described immediate/acute reactions to stress-related chemical cues (SC – Stress Cue) in fish. Specifically, we evaluated the effects of SC on ventilation rate (VR) and feeding behavior in Nile tilapia (Oreochromis niloticus), a highly relevant species for world aquaculture, therefore, to understand the diversity of stressful contexts and stress responses in this species have important practical applications (stress reduction). Stress cue was obtained from conspecifics exposed to a handling stressor. Stress was confirmed by measuring plasma cortisol levels. The responses to SC were contrasted to chemical control cues: a cue originated from non-stressed conspecifics and pure water (vehicle control). We observed that Nile tilapia exposed to SC had an increase in VR, but without effects on feeding behavior (feeding latency and ingestion). Thus, the SC is a stressor that induces readily stress response (VR increase), suggesting sympathetic activation, but did not change feeding performance. In practical terms, it is positive because although social propagation of stress via SC elicits a stress response, it did not harm appetite. [ABSTRACT FROM AUTHOR]

Tilapia lake virus (TiLV) is a novel single-stranded RNA virus that is considered a threat to the universal tilapia industry. Recombinant technology proved to apply to different viruses and does not require handling live viruses. The present study developed a recombinant protein from segment 4 of TiLV with the aim of developing an immunological detection method for the virus. For this purpose, the complete coding sequence of segment 4 of the virus was optimized, amplified, and cloned in pET-28a(+), a prokaryotic expression vector, and the TiLV segment 4 construct (pET-seg4) was developed. The recombinant protein was expressed in BL21-competent Escherichia coli by isopropyl-β-D-thiogalactopyranoside (IPTG) induction. The successful expression of the recombinant protein was confirmed by SDS-PAGE. The polyclonal antibody (PAb) raised against the recombinant protein was used for the indirect enzyme-linked immunosorbent assay (ELISA) development to detect TiLV in the pooled kidney and mucus samples. The coating concentrations for the recombinant protein and the TiLV-positive samples were standardized as 3.125 µg and 6.25 µg, respectively, and the optimum polyclonal antibody dilution was found as 1:800. The diagnostic sensitivity and diagnostic specificity of the assay were 82.35% and 100%, respectively. The recombinant protein developed in this study provided a better understanding of raising a codon-optimized protein and its use in developing an indirect ELISA test for TiLV, which can also be used as a recombinant vaccine for immunizing tilapia. [ABSTRACT FROM AUTHOR]

The problem most often encountered in fish farming is disease which can cause a decrease in fish production levels. Parasites cause one of the infectious diseases found in fish farming. The presence of parasites can cause a decrease in the quality of the growth of fish production. The purpose of this study was to identify the prevalence of ectoparasites on Nile tilapia in Sidoarjo, Indonesia. Ninety-six samples from two ponds were examined under the microscope to find out the presence of ectoparasite that exists in the outside body part of the fish. Samples were collected from skin, fins, tail, and gills using native methods and observed under a microscope in the Division of Parasitology Laboratory, Faculty of Veterinary Medicine, Universitas Airlangga. The results of this study showed 86 samples positively infected by ectoparasite and 10 showed negative. The ectoparasites found in this study were Trichodina sp., Chilodonella sp., Ichthyophthirius multifillis, Gyrodactylus sp., and Dactylogyrus sp. The highest prevalence is Trichodina sp. and Dactylogyrus sp. The number of fish infested by ectoparasite is 89.56%, this is classified in the usual category. The highest prevalence occurs in infestations of Trichodina sp. i.e.72.91% which were contained in the 70 samples. While the lowest prevalence was in Gyrodactylus sp. by 8.32% in 8 fish samples. Double infections from two different ponds were 70% within 33 samples which were included in the usual category. [ABSTRACT FROM AUTHOR]

Two tilapia species, Oreochromis aureus and Oreochromis niloticus, were introduced into Morocco in 2004 for fish farming. O. niloticus was subsequently introduced into the wild in several watersheds. During a fish survey at six locations, we observed other specimens of tilapia that appear to be more related to O. aureus. Partial sequences of COI and S7 genes and geometric morphometrics were used to assess the specific status of all the specimens. Out of 1691 specimens sampled, 159 COI and 153 S7 partial sequences were obtained and confirmed the presence of both species. O. aureus was present in part of Rabat-Salé-Kenitra region (the Nador Channel (NC), Al Kansra dam (AK) and Oued Sebou (OS)) while O. niloticus was found in the fish farm (AS), in the province of Rabat (Sidi Mohamed Ben Abdellah dam (BA)) and the region of Casablanca-Settat (Al Massira dam (AM)). A few hybrids were identified at AS and OS. Body shapes and sizes were assessed using geometric morphometrics with 18 landmarks and were found to differ significantly between O. aureus and O. niloticus. Both species exhibited significantly different allometric changes during their growth, but kept their morphological signature independently of their specific allometric changes during growth. Specimens from riverine environments (OS, NC) had a similar shape with an elongated body with a large head and eye, while individuals found in lacustrine environments (AK, AM and BM) had a larger body depth, small head and eye. Morphometrics also suggested that hybrids or sympatry could occur to a small extent in AS, OS and NC. [ABSTRACT FROM AUTHOR]

In this study, a high vacuum flavor extraction (HVE) device was developed to address the limitations of traditional extraction methods, such as extended extraction times and artifact generation during high-temperature processes. Firstly, the repeatability and precision of the HVE method were evaluated through quantitative analysis of twelve volatile odor compounds across seven replicate extractions using gas chromatography–flame ionization detection (GC-FID). The results showed that the HVE system achieved a mean relative standard deviation (RSD) of 11.60 ± 1.79% and a recovery rate of 90.55 ± 4.56%, demonstrating its precision and reproducibility. Secondly, the performance of HVE was compared with solvent-assisted flavor evaporation (SAFE) and simultaneous distillation–extraction (SDE) for extracting flavor compounds from fried tilapia mince. The results indicated that HVE was more effective, particularly in extracting aldehydes and pyrazines, which are key contributors to the flavor profile. Finally, sensory evaluations supported these findings, showing that the odor profiles obtained through HVE were most similar to the original sample, with a similarity score of 72.55%, compared to 69.25% for SAFE and 60.29% for SDE. These findings suggest that HVE is a suitable method for the extraction and analysis of volatile compounds in complex food matrices such as fried tilapia mince. [ABSTRACT FROM AUTHOR]

Intensified production of stocker‐size tilapia can be accomplished using the biofloc technology production system. Stocker‐size tilapia (ca. 10–200 g/fish) are raised for subsequent stocking for grow‐out to market size. The relationship between stocking rate and the production of stocker‐size hybrid tilapia (Oreochromis aureus × O. niloticus) was evaluated in two studies in outdoor mixotrophic biofloc tanks. Hybrid tilapia were stocked in 18.6‐m2 (15.7‐m3) tanks at 50–150 fish/m2 (59–178 fish/m3) in 25 fish/m2 (30 fish/m3) increments in Study 1 and grown for 141–143 days. Stocking rates evaluated in 4.7‐m2 (3.6‐m3) tanks during Study 2 over 78–79 days ranged from 100 to 300 fish/m2 (132–396 fish/m3) in 25 fish/m2 (33 fish/m3) increments. Linear regression models best described growth to stocker size in both studies. Fish yield increased linearly with stocking rate and ranged from 20.1 to 38.3 kg/m3. Individual weight at harvest was inversely related to stocking rate and ranged from 389.8 to 163.4 g/fish and 155.2 to 81.4 g/fish in Studies 1 and 2, respectively. Partial budget analyses suggested positive net changes in profit with incremental increases in stocking rate for producing a 75‐g stocker. Water quality concentrations were impacted directly by daily feed ration and total feed fed, which increased linearly with stocking rate. In Study 2, whole‐body dry matter, protein, protein retention, and lipid were unaffected by stocking rate, whereas whole‐body ash increased with stocking rate. Whole‐body energy retention significantly decreased with stocking rate. The outdoor mixotrophic biofloc production system is well suited for intensive production of hybrid tilapia stockers. However, additional replicated research and economic analysis are needed to evaluate stocking rate and culture duration to produce specific‐sized stocker hybrid tilapia. [ABSTRACT FROM AUTHOR]

As an omnivorous fish, wild tilapia feed on both animal and plant foods, depending on what is available. To understand the nutritional function of the gut microbiota of tilapia, we used shotgun metagenomic sequencing, untargeted metabolomics analysis, and 16S rRNA gene sequencing to study the metabolites and gut microbial communities in tilapia eating different diets (artemia nauplii in the carnivorous diet; plant‐based pelleted feed [PBP] in the herbivorous diet; and a mixture of these two in the omnivorous diet). A total of 225 Nile tilapia (Oreochromis niloticus) were cultured in nine 1500 L outdoor tanks, with three replicate tanks per diet and 25 fish per tank. β‐diversity analysis revealed that there was no significant difference in microbial structure between the three diets. However, significant differences were detected in gut metabolites. The abundance of the core bacteria in tilapia intestine (genus Cetobacterium) increased significantly when an omnivorous diet was fed. Cetobacterium abundance was significantly correlated to some differential metabolites including glucose and amino acids, and significantly correlated to pathways of carbohydrate and amino acids metabolism, identified by metagenome analysis. Metagenomic binning produced seven Cetobacterium MAGs with the completeness >50% and contamination <10%, in which genes related to the above metabolites and metabolism pathways were identified. All seven MAGs contained CAZymes that could act on distinct carbohydrates, providing highly diversified capabilities to this genus to cope with both animal and plant glycans. These tilapia fed with an omnivorous diet also showed increased growth. The differential intestinal metabolites aspartate, isoleucine, ornithine, proline, nicotinate, and NAD+ could be related to the increased growth. Our results expanded the understanding of how tilapia have adapted to an omnivorous diet and may provide knowledge for improving aquaculture management. [ABSTRACT FROM AUTHOR]

The present study aimed to determine the anaesthetic effectiveness, safety, and applicable concentrations of coriander (Coriandrum sativum) essential oils (CEO) for three-spotted tilapia (Oreochromis andersonii). For this purpose, CEO concentrations of 400, 500, and 600 µL/L were tested at two temperatures, 20.90 ± 1.19 °C and 30.60 ± 0.92 °C, on three different sizes (small, medium, and large) of the fish in duplicate glass aquaria with 200 mg/L of tricaine methanesulfonate (MS-222) served as the control. The sedative efficacy during simulated transportation experiments was also carried out. The results demonstrated that the induction and recovery time in O. andersonii anaesthetised with CEO were significantly influenced by concentration, water temperature, and fish size (P < 0.05). A concentration of 600 µL/L of CEO was found to be highly effective in inducing deep anesthesia and promoting rapid recovery in small and medium-sized fish at both water temperatures (20 and 30 °C). Based on this study, 100 µL/L of CEO is recommended for short-term transportation lasting up to 4 h, while 50 µL/L is advised for longer-distance transport. Although coriander essential oil shows anaesthetic effectiveness in three-spotted tilapia, further research is needed to fully understand the efficacy and safety of CEO across different fish species. [ABSTRACT FROM AUTHOR]

ABSTRACT Water temperature is a critical environmental parameter that significantly influences fish metabolism. This study assessed the metabolism of florfenicol (FF) in tilapia (Oreochromis niloticus) at water temperatures typical of tropical and subtropical regions. Fish were treated with FF by oral administration of a dose of 10 mg kg−1 bw for 10 consecutive days. Fish fillet, liver, and kidney were sampled during the treatment phase (1, 5, and 10 days) and posttreatment (1, 2, 3, and 5 days after the last FF administration). FF, florfenicol amine (FFA), monochloro florfenicol (FFCl), and florfenicol alcohol (FFOH) were determined in the sampled tissues using a validated LC–LC–MS/MS method. The highest FF, FFA, and FFOH concentrations were determined on day 5 during the treatment phase. For FF, the concentration order is kidney > liver > fillet, while for the metabolites FFOH and FFA, the order is liver > kidney > fillet. In fillet and liver, the concentrations of FFOH were higher than the FFA concentrations, indicating that FFOH was the primary metabolite in these tissues. FFCl was only quantified at concentrations lower than 90 μg kg−1 in all tissues. The results indicated that FF can be readily absorbed and rapidly eliminated in tilapia cultivated in warm water environments. This study revealed FFOH as the primary and most persistent metabolite in tilapia farmed in warm water, followed by FFA. [ABSTRACT FROM AUTHOR]

Microplastic (MP) ingestion through fish consumption is a concern for human exposure. While the presence of plastic particles in fish tissues has been documented worldwide, information on microplastic concentrations in edible tissues, especially those smaller than 10 µm, remains scarce. Spectrometric techniques provide a complementary analytical tool to measure MP mass for human exposure studies without intrinsic size limitations; however, their application to fish analysis is limited. In this study, we utilized pyrolysis gas chromatography–mass spectrometry (Py-GC–MS) for the identification and quantification of MPs in fish muscle tissues. Two sample preparation methods, pressurized liquid extraction, and chemical digestion, were tested for compatibility with Py-GC–MS analysis. An analytical method using chemical digestion was validated for analyzing particles ≥ 0.7 µm for 4 polymer types: polypropylene, polyethylene, polystyrene, and polymethyl methacrylate. The developed method was applied to 24 adult Nile tilapia (Oreochromis niloticus) samples from a recirculating aquaculture system. MPs were detected in 42% of the samples, with an average concentration of 0.14 ± 0.32 µg/g, while high variations within subsamples were observed. Our findings reveal trace amounts of MPs in edible fish tissues from aquaculture, highlighting the potential risk of microplastic ingestion through fish consumption. This underscores the need for further risk assessments to evaluate the impact on human health and to develop appropriate mitigation measures. [ABSTRACT FROM AUTHOR]

Curcumin, the main polyphenol component of turmeric powder, has garnered increasing attention as an effective supplement in fish diets. A comparative trial was conducted to evaluate the impacts of dietary supplementation with different forms of curcumin (free, in combination, or nanoparticles) on hemato-biochemical parameters, reproductive capacity, and related gene expressions of red tilapia (Oreochromis niloticus x O. mossambicus) broodstock. Fish (n = 168) were fed an isonitrogenous (30% CP), isocaloric (18.72 MJ kg − 1) diet containing basal diet (Control), 60 mg kg-1 of either free curcumin (Cur), curcumin/nano-curcumin blend (Cur/NCur), or nano-curcumin (NCur) for 56 days. Red tilapia broodstock (155 ± 5.65 g) were stocked at a male: female ratio of 1:3. Blood samples and gonads were collected to assess hemato-biochemical parameters, reproductive capacity, and related gene expression at the end of the feeding trial. The results indicated that the values of hematological parameters (RBCs, WBCs, hemoglobin), total protein, albumin values, and reproductive hormones (T, LH, and FSH) were significantly increased, while liver function enzymes were decreased in the NCur group (P < 0.05). Reproductive performances (GSI, gonad maturation, total number of fry per female) were significantly improved in the NCur group compared with those in other groups (p < 0.05). The expression of reproductive genes (CYP19A1A, FSHR, LHR, FOXL2A, ESR1, ESR2A, and PGR) were significantly up‐regulated in the gonads of fish fed NCur. Collectively, feeding red tilapia diets containing NCur led to noticeably better results followed by Cur/NCur blend, then free Cur compared to the control diet. These results indicate the superiority of NCur over its free or blended form, suggesting that a diet containing about 60 mg/kg of NCur is beneficial for enhancing hemato-biochemical parameters, improving reproductive performance, and enhancing the gonadal architecture of red tilapia. [ABSTRACT FROM AUTHOR]

Air frying as a new roasting technology has potential for roasted fish production. In this study, the changes in volatile compounds (VCs) during air frying of tilapia were studied by quantitative gas chromatography–ion mobility spectrometry, followed by the identification of key VCs based on their odor activity value (OAV). There were 34 verified VCs, of which 16 VCs were identified as the key VCs with OAV ≥ 1. Most of the VCs were improved by air frying and peaked at 20 min. During the air frying, the total sulfhydryl content markedly decreased, while the protein carbonyl and MDA content significantly increased, suggesting the enhancement in the oxidation of lipids and proteins. The correlation network among the chemical properties and key VCs was constructed. The change in total sulfhydryl, protein carbonyl, and MDA showed significant correlation with most of the key VCs, especially 2-methyl butanal, ethyl acetate, and propanal. The results indicated that the oxidation of lipids and proteins contributed the most to the flavor improvement in air-fried tilapia. This study provides a crucial reference for the volatile flavor improvement and pre-cooked product development of roasted tilapia. [ABSTRACT FROM AUTHOR]

This experiment was performed to identify the influence of dietary Saussurea lappa root (SLR) on the performance and general health status of Nile Tilapia fingerlings (O. niloticus). Four formulated diets with different SLR levels of 0.0, 2.5, 5 and 10 g/kg, respectively, were afforded to fingerling fish (15.42 ± 0.05 g) for 8 weeks. The feed efficiency ratio (FER), feed intake (FI) and feed conversion ratio varied with dietary SLR level in a linear model and a high feed efficiency rate was recorded at the 10 g/kg group, while FI and FCR exhibited an opposite trend (P < 0.001). Dietary SLR level influenced serum protein constituents, liver and renal function enzymes, triglycerides, cholesterol and glucose (P < 0.001). Serum Catalase (CAT), total antioxidant capacity (T‐AOC) and superoxide dismutase (SOD) remarkedly increased with dietary SLR level and attained a level at 10 g/kg. Furthermore, serum lysozyme, complement C3 (C3), IgA and IgD were stimulated by 10 g/kg SLR. Intestinal digestive enzymes (lipase and amylase) increased with SLR level up to 10 g/kg. As the dietary SLR level raised, the cumulative survival percentage aginst A. hydrophila challenge increased and then reached a maximum at 10 g/kg SLR group. Moreover, gene expression of pro‐inflammation cytokines (TNF‐2a, IL‐1β, and IL‐10) in liver and kidney transcriptomes demonstrated effective immunostimulant capabilities of greater SLR inclusion levels in fish diet. Meanwhile, intestinal microbial investigation, revealed that high levels of SLR in tilapia fish feed significantly suppressed total bacterial count, and pathogenic bacterial count (such as, E. coli, Coliform, Aeromonas spp, Pseudomonas spp.), and stimulated lactic acid bacteria development. Finally, it is recommended to include a high level of SLR (5 or 10 g/kg) in the diet of O. niloticus fingerlings to enhance feed efficiency, antioxidant characteristics, and immunological response against bacterial infections. [ABSTRACT FROM AUTHOR]

Oreochromis niloticus is the most important aquacultural species worldwide. Several countries are interested in repopulating natural or artificial reservoirs with the fry of tilapia (Oreochromis sp.) to develop new fisheries or to enhance the existing ones. However, as tilapia is considered an invasive species, it is essential to check the existence of the species in the place before releasing any fry. Characterization of tilapia species with meristic is unreliable because of existing morphological similarities among species. In this work, the composition of the tilapia species of Laguna El Mastranzo (LEM), Nayarit, Mexico, was explored for the first time through a molecular method using the mitochondrial DNA control region. Three tilapia species (Oreochromis niloticus, O. aureus, and O. urolepis) were found in LEM, and it was confirmed that the two commercial strains (Aquamol and Spring) intended for repopulation were O. niloticus. Seven haplotypes of mitochondrial DNA control region sequences were obtained: three in LEM, three in Aquamol, and one in Spring strains. Before repopulating any reservoir, a molecular verification strategy is recommended to avoid spreading the species. The results of this work represent a glimpse into the genetic material of LEM, Nayarit, Mexico. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The Nile tilapia (Oreochromis niloticus) and the African sharptooth catfish (Clarias gariepinus) are the most widely cultivated fish species in Egypt. The production cycle runs from spring to autumn, during which water temperatures are conducive to fish growth and the propagation of leeches, which transmit fish hemoflagellates (Trypanosoma spp.). A total of 710 Nile tilapia and 385 catfish were randomly collected from three different sites--two private farms and Burullus Lake--throughout the year. Fish blood samples were examined for Trypanosoma infection. Regardless of fish species or collection site, the highest infection rate of T. mukasai was observed during summer. The catfish samples showed a higher infection rate than the Nile tilapia, and fish farms had higher infection rates compared to Burullus Lake. A positive correlation was found between Trypanosoma infection and water temperature, nitrogenous compounds (unionized ammonia, nitrite, and nitrate), total bacterial count (TBC), and total coliform count (TCC). Based on these findings, Trypanosoma infection can be expected during the production cycle (spring to autumn), and it is recommended to maintain optimal water parameters to prevent conditions favorable to infectious agents. [ABSTRACT FROM AUTHOR]

Enterococcus faecium, a member of the Enterococcus genus, has emerged as a significant concern in aquaculture due to its potential pathogenicity and antibiotic resistance. This study aimed to investigate the molecular diagnosis and characterization of six different Enterococcus species isolated from the gastrointestinal tracts of the common carp (Cyprinus carpio) and tilapia (Oreochromis niloticus) and to evaluate their genetic diversity, antibiotic resistance profiles, and potential virulence factors. Among the isolates, 65.3% of the common carp and 60.8% of the tilapia were identified as E. faecium. All six species demonstrated the ability to metabolize various carbohydrates, indicating a broad metabolic capacity. Some species showed variability in their utilization of specific carbohydrates. For example, E. faecium and E. faecalis uniquely fermented adonitol, while E. avium and E. hirae were the only ones capable of fermenting D-arabitol. Additionally, Voges-Proskauer positivity was exclusively observed in E. faecalis. In terms of growth conditions, all species thrived at both 4°C and 45°C, except for E. faecalis, which failed to grow at 10°C. E. faecium and E. faecalis grew well at pH 9.6. Hemolysis tests revealed differences among the species: E. faecalis displayed beta-hemolysis, while E. gallinarum exhibited alpha-hemolysis. Motility was observed only in E. gallinarum, and esculin hydrolysis was exclusive to E. faecalis. Environmental adaptability varied among the species. E. avium showed limited growth in 6.5% NaCl, and some species exhibited little to no growth in 0.1% methylene blue milk. E. faecalis and E. faecium demonstrated survival at 60°C for 15 minutes, with E. faecium showing limited survival at 30 minutes, distinguishing them from the other species. The strains isolated from Cyprinus carpio and Oreochromis niloticus collected from local fish farms in Basrah City were confirmed as E. faecium through 16S rRNA gene sequencing. A PCR study using specific primers identified all isolates as E. faecalis. [ABSTRACT FROM AUTHOR]

One of the main challenges in the tilapia culture in Malawi is the low growth rates and yields. This study aimed to compare iso-nitrogenous fish feeds concerning growth, feed utilization, and apparent digestibility of the redbreast tilapia (Coptodon rendalli) raised in pond-hapas and tanks. Coptodon rendalli fingerlings were stocked in hapas (1m² each) at 10 fish per hapa, each measuring 6.81± 0.33g, and reared for 70 days. The fish were fed on floating, sinking, and maize bran (control) feeds. In a parallel digestibility experiment, six aquarium glass tanks were stocked with 10 Coptodon rendalli fingerlings, each for 21 days. Fecal material was collected and transferred into conical flasks after one hour of feeding for storage at -20°C. Results showed significant differences in specific growth rate, weight gain, relative condition factor, final weight, and survival rate, with floating feeds yielding the highest values (P< 0.001). The fish displayed negative allometric growth, with a growth coefficient of b=1.84. Apparent feed conversion ratio and protein efficiency ratio varied significantly across treatments (P< 0.001). In the digestibility experiment, differences in protein digestibility were also significant (P< 0.001), while no significant differences were observed in fat (P = 0.22), ash (P = 0.53), and energy (P = 0.34) across treatments. Fish fed on floating feeds exhibited better growth, feed utilization, and digestibility, highlighting the need to enhance the use of floating feeds in aquaculture [ABSTRACT FROM AUTHOR]

Motile aeromonad septicemia (MAS), caused by the Aeromonas species, has been a serious problem in fish health management, particularly in Nile tilapia (Oreochromis niloticus). This study characterized an Aeromonas species isolated from farmed tilapia fingerlings in Binangonan, Rizal, Philippines, and tested for its pathogenicity in tank trials. The isolate, designated as Aeromonas veronii DFR01 (Diseased Fish Rizal), was identified based on 16S rRNA phylogenetic analysis, 16S rRNA homology, and MALDI-TOF mass spectrometry. Its biochemical profile was generated from API and Biolog Gen III systems. A median lethal dose of A. veronii DFR01 was determined to be 107 CFU/mL in tank trials and was utilized as a whole-cell inactivated antigen for oral vaccine development. The immunized tilapia fingerlings produced elevated levels of immunoglobulin M (IgM) in the blood as determined by an enzyme-linked immunosorbent assay (ELISA). There was a significant increase in IgM levels 14 days post-vaccination. A quantitative polymerase chain reaction (qPCR) showed increasing levels of IgM gene expression after vaccination until 38 days of culture. Vaccinated fish showed 25–35% cumulative mortality after the challenge, while non-vaccinated-challenged fish showed 75% mortality. The findings of this research suggest that the fish oral vaccine may prove beneficial for farmed tilapia populations. The vaccine elicited improved immune responses in the fish and resulted in higher survival rates. [ABSTRACT FROM AUTHOR]

This study aimed to assess the effect of dietary supplementation of a mixture of botanical compounds and essential oil (Phyto AquaMeric, PAM) on the growth, immune and antioxidant parameters and environmental benefits in Nile tilapia. Two diets including a control and a PAM-supplemented diet at 0.5 g kg−1 were prepared for the trial. The diets were isonitrogenous (30% crude protein) and isoenergetic (17 MJ kg−1) extruded diets. Nile tilapia weighing initially 74.22 ± 1.96 g fish−1 were stocked in 2 m3 hapas at a density of 20 fish per m3 (40 fish per hapa). Each group was tested in triplicates over 80 days. The antioxidant potential of PAM was compared to vitamin C through KRL test, showing a higher value from 35 to 100 mg. The in vivo trial did not exhibit any significant growth performance improvement. However, the PAM group had a significantly improved feed conversion ratio (FCR) and protein efficiency ratio (PER). Moreover, the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx), Malondialdehyde (MDA), immune parameters (ACH50, lysozyme, phagocytic and phenoloxidase activities), digestive enzymes and hepatic enzymes were significantly improved in the PAM-fed group. An evaluation of eutrophication potential of PAM supplementation revealed a low input in the system. In conclusion, this mixture of botanicals and essential oil exhibited in vitro and in vivo antioxidant potential, improved health and digestive parameters and contributed to a reduced eutrophication risk in the tilapia production system. [ABSTRACT FROM AUTHOR]

Euryhaline fish experience variable osmotic environments requiring physiological adjustments to tolerate elevated salinity. Mozambique tilapia (Oreochromis mossambicus) possess one of the highest salinity tolerance limits of any fish. In tilapia and other euryhaline fish species, the myo-inositol biosynthesis (MIB) pathway enzymes, myo-inositol phosphate synthase (MIPS) and inositol monophosphatase 1 (IMPA1.1), are among the most upregulated mRNAs and proteins indicating the high importance of this pathway for hyperosmotic (HO) stress tolerance. These abundance changes must be precluded by HO perception and signaling mechanism activation to regulate the expression of MIPS and IMPA1.1 genes. In previous work using a O. mossambicus cell line (OmB), a reoccurring osmosensitive enhancer element (OSRE1) in both MIPS and IMPA1.1 was shown to transcriptionally upregulate these enzymes in response to HO stress. The OSRE1 core consensus (5′-GGAAA-3′) matches the core binding sequence of the predominant mammalian HO response transcription factor, nuclear factor of activated T-cells (NFAT5). HO-challenged OmB cells showed an increase in NFAT5 mRNA suggesting NFAT5 may contribute to MIB pathway regulation in euryhaline fish. Ectopic expression of wild-type NFAT5 induced an IMPA1.1 promoter-driven reporter by 5.1-fold (P < 0.01). Moreover, expression of dominant negative NFAT5 in HO media resulted in a 47% suppression of the reporter signal (P < 0.005). Furthermore, reductions of IMPA1.1 (37–49%) and MIPS (6–37%) mRNA abundance were observed in HO-challenged NFAT5 knockout cells relative to control cells. Collectively, these multiple lines of experimental evidence establish NFAT5 as a tilapia transcription factor contributing to HO-induced activation of the MIB pathway. NEW & NOTEWORTHY: In our study, we use a multi-pronged synthetic biology approach to demonstrate that the fish homolog of the predominant mammalian osmotic stress transcription factor nuclear factor of activated T-cells (NFAT5) also contributes to the activation of hyperosmolality inducible genes in cells of extremely euryhaline fish. However, in addition to NFAT5 the presence of other strong osmotically inducible signaling mechanisms is required for full activation of osmoregulated tilapia genes. [ABSTRACT FROM AUTHOR]

Irisin is a recently discovered myokine that facilitates the browning of white adipose tissue, increases glucose uptake in skeletal muscle, and influences metabolic processes in the liver. However, its potential effects on amino acid absorption remained largely unexplored. This study aimed to elucidate the role of irisin in modulating amino acid uptake and delineate the underlying molecular mechanisms involved. To this end, juvenile tilapia were administered intraperitoneal irisin injections at 100 ng/g body weight over 8 weeks. Evaluation of various physiological parameters revealed that irisin supplementation significantly improved the specific growth rate and feed conversion efficiency while reducing feed consumption. Muscle tissue analysis revealed that irisin significantly modified the proximate composition by increasing protein content and reducing lipid levels. It also significantly raised the levels of both essential and non-essential amino acids in the muscle. Histological analysis demonstrated that irisin-stimulated muscle growth through hyperplasia rather than hypertrophy, corroborated by upregulated IGF-1 mRNA and downregulated myostatin mRNA expression. Mechanistic studies in cultured tilapia muscle cells elucidated that irisin activated integrin receptors on muscle cells, which subsequently engaged IGF-1/IGF-1R signaling. Downstream of IGF-1R activation, irisin simultaneously stimulates the ERK1/2 and PI3K/mTORC2/Akt pathways. The convergence of these pathways upregulates L-type amino acid transporter 1 expression, thereby augmenting amino acid uptake into muscle cells. In summary, irisin supplementation in tilapia leads to improved muscle growth, predominantly via hyperplasia and augmented amino acid assimilation, governed by intricate cellular signaling pathways. These findings provide valuable aquaculture applications and novel insights into muscle development. [ABSTRACT FROM AUTHOR]

Burn injury remains a health problem, specifically in Indonesia. In major burns, xenograft has been proved to be useful as temporary wound coverage. However, some xenografts are not widely available due to cultural, financial and religious backgrounds, or have an unesthetic appearance, such as the scaly appearance of tilapia fish xenograft.Striped catfish (Pangasius hypophthalmus) is a scaleless fish that has abundant type 1 collagen. This study aimed to compare striped catfish skin to commonly used xenograft (Nile tilapia and porcine skin) as xenograft material for burn wound. In this experimental study, nine different skin samples of striped catfish, Nile tilapia and porcine were prepared and histologically examined using hematoxylin-eosin stained samples. Macroscopic and microscopic features of each sample were documented and analysed. The macroscopic skin appearances of striped catfish were hairless and scaleless with black-silver color and moderate thickness. As for microscopic features, the epidermal thickness of striped catfish skin (8.49±1.60 μm) was significantly different to both Nile tilapia (2.18±0.37 μm; p<0.001) and porcine skin (42.22±14.85 μm; p=0.002). The dermal thickness of striped catfish skin (288.46±119.04 μm) was similar to Nile tilapia (210.68±46.62 μm; p=0.783) but differs significantly to porcine skin (1708.44±505.12 μm; p<0.001). The integrity and collagen organization of striped catfish was also similar to tilapia based on semi-quantitative histology scoring system (p>0.05). Striped catfish had potential macroscopic appearance and comparable microscopic features to Nile tilapia; smoother macroscopic appearance, thicker epidermis, and similar dermis thickness. Therefore, we believe it can be potentially used as a xenograft material. Further studies are required to evaluate the effectiveness and feasibility of striped catfish xenograft in burn wound management. [ABSTRACT FROM AUTHOR]

• Four methods with different cooling rates were applied to the tilapia freezing. • Volatile bases (TBV-N), thiobarbituric acid (TBARS), microstructure were analyzed. • TBV-N, colors parameters and TBARS were statistically significant in all treatments. • Air blast and combined method altered less the texture of fillets after storage time. • Cryogenic freezing showed thermal stress, cracking and tissue quality damaged. The Nile tilapia (Oreochromis niloticus) fillets were frozen with static air (SA) at -20 °C, air blast freezing (AF) at -25 °C, combined method (CM - immersion in liquid nitrogen followed by AF) and cryogenic freezing (CF - immersion in liquid nitrogen). The effects of different freezing methods and of storage time at -18 °C (0, 30, 60 and 90 days) on fillet quality were evaluated. The temperature records were obtained, and the freezing times were determined by monitoring the temperatures of the geometric centers of the fillets. For CF, CM, AF and SA, the freezing times were 5.32, 127, 146 and 268 min, respectively. The quality of the frozen fillets was evaluated by measuring pH, volatile nitrogenous bases (TBV-N), thiobarbituric acid reactive substances (TBARS), and fatty acids and by obtaining a texture profile and performing scanning electron microscopy (SEM). The samples frozen by CF, after storage, had the highest levels of TBV-N because the high freezing rate produced superficial cracks that negatively affected the quality of the fillets. Freezing the samples with SA produced the worst quality indices and the microstructure was visibly damaged, with greater spaces between the fibers left by ice crystals. For all parameters evaluated, freezing with AF and CM resulted in fast freezing rates and better-quality tilapia fillets for 90 days of storage. [Display omitted] [ABSTRACT FROM AUTHOR]

Summary: The combined effects of gelatin extraction methods and protease types on the functional properties of tilapia scale gelatin hydrolysates (TSGH) were investigated. The tilapia scale gelatin (TSG) was extracted after acid/base pretreatments, respectively, and then hydrolysed with different proteases to produce TSGHs. The degree of hydrolysis and the content of trichloroacetic acid soluble peptide were increased with hydrolysis time, while the content of β‐sheet was decreased significantly with the hydrolysis time (P < 0.05). The emulsification stability of acid protease hydrolysate (APH) was higher than that of neutral protease hydrolysate (NPH) and alkaline protease hydrolysate (ALPH). All samples showed good resistance to oxidation: DPPH (20%–64.66%), ABTS (29.08%–63.04%), and iron reducing power (0.017–0.499). The hydrolysates obtained from the base‐pretreated TSG showed higher antioxidant properties than acid‐pretreated TSG. The antioxidants of different protease hydrolysates are ranked by ALPH > NPH > APH. In conclusion, gelatin extraction methods and its hydrolysis conditions had influences on the functional properties of TSGH, and the study of the processing of marine biological wastes is of great significance in realising their high‐value utilisation and reducing the burden on the environment. [ABSTRACT FROM AUTHOR]

Lysophospholipids (LPL) are usually used as emulsifiers in fish nutrition because of their ability to ameliorate nutrient digestibility and lipid metabolism. The present study aims to assess the effects of a commercial dietary lysophospholipid on growth performance, feed utilization, antioxidant activity, innate immunity and biochemical indices of red tilapia (Oreochromis niloticus x O. mosambicus) fingerlings. Five isonitrogenous (35.8% CP) and isocaloric (18.7 MJ kg−1) diets were prepared as follows: two control diets coded as C1 and C2, containing 2 and 1% soybean oil, respectively. The other three diets were coded as LPL1, LPL2 and LPL3, and were formulated by supplementing the C2 diet with 0.1, 0.2 and 0.3% lysophospholipid. The fingerlings of red tilapia (2.13 ± 0.42 g fish−1) were fed the diets for 70 days. The highest significant (p < 0.05) final weight and weight gain were recorded in LPL2. The best values of feed efficiency and protein efficiency (PER)were in all fish groups fed LPL in their diets (p < 0.05). Protein productive value (PPV) showed the highest result in LPL3 (p < 0.05). Lysozyme activity showed the best result in LPL3 (p < 0.05). The highest values of alternative complement activity (ACH50) and total immunoglobulin (Ig) were in LPL3 and LPL2 (p < 0.05). The best results of superoxide dismutase (SOD) and catalase activity were recorded in LPL3 (p < 0.05). The lowest values of triglycerides (TG) and total cholesterol (CHO) were detected in LPL1 and LPL2 (p < 0.05). Thus, the inclusion of 0.2% of the commercial lysophospholipid in red tilapia diets enhanced the growth performance, feed utilization, innate immunity, antioxidant activity and lipase activity, and reduced CHO and TG of red tilapia fingerlings. [ABSTRACT FROM AUTHOR]

More than a billion people worldwide eat fish as their primary source of high-quality protein. Fish parasites have a direct impact on fish productivity, and a secondary impact on human health. This study was carried out to assess the occurrence of endoparasites in Tilapia zillii (Gervais, 1848) from Tono reservoir, Navrongo, Ghana. A total of 120 fish samples were collected from the up-stream, mid-stream and downstream regions of the reservoir using cast nets. All the collected fish samples were transported to the research laboratory in the University for Development Studies and examined for ectoparasites during January 2022 to August 2022. Five ectoparasites namely Trichodina sp. of Protozoans ciliates, Dactyolgyrus sp. of Monogenean, Argulus sp. and Lernaea sp. of Crustaceans and the Diplostomum sp were identified. Overall prevalence of the fish parasites was 52.32 %. The intensity of the parasites observed ranged between 1.58% and 3.52%. Highest prevalence (70%) was reported in the dry season, while the lowest (31.67%) was reported in the rainy season. Female fish samples had a higher prevalence (64.47%) than males (27.27%). Fish of the down-stream had the highest prevalence (92.5%) than the up-stream (17.5%). Fish samples with maximum length and weight were highly (65.15%) infected than small-sized fish with low body length and weight (33.33%). This study shows that the dry season (January, February, March, and April) affects the fish business and results in poor quality fish meat with risk of disease infection. [ABSTRACT FROM AUTHOR]

Highly nutritious insects, such as black soldier fly (BSF) larvae, also referred to as maggot, have been evaluated as feed in monoculture systems, but their use in multi-trophic systems has not been previously investigated. This study used maggotbased feed in a multi-trophic system on a laboratory scale to evaluate the survival and growth performance of tilapia (Oreochromis niloticus). Tilapia were cocultured with freshwater lobster, freshwater clams, and paddy. Four experimental diets were used including a commercial pellet as a control (CP), live maggots (LM), dried maggots (DM), and supplemented maggots (SM). Tilapia (initial weight, 4.1 ± 0.2 g) and other organisms were reared in plastic tanks (water volume 50 L) and randomly distributed into 12 tanks, each containing 20 individual tilapia. The experimental diets were given four times a day at a feeding rate of 10% tilapia biomass. After 28 days of feeding, the survival and growth of tilapia on the CP diet were 90.0% and 2.8% day-1, LM 93.3% and 2.7% day-1, DM 93.3% and 3.3% day-1, and SM 90.0% and 3.1% day-1, respectively. There was no significant effect (P > 0.05) on the survival performance among the experimental diets. However, the growth confirmed by Specific Growth Rate (SGR) showed a significant effect (P < 0.05). SGR values were found to be significantly higher in the DM and SM diets than in the CP diet. An important finding of this research is the potential of maggot-based feed to increase the growth of tilapia in multi-trophic systems without impairing their survival. [ABSTRACT FROM AUTHOR]

Understanding genetic variation among species is essential for effective selection and breeding enhancements. This study was conducted to assess the genetic diversity among three tilapia species (Oreochromis niloticus, Oreochromis aureus, and Oreochromis mossambicus) from several rivers located in South-South Nigeria. A total of 300 samples representing the three species were used for this research. Blood samples were collected from all individuals for DNA extraction, amplification, and sequencing of the mitochondrial (mt) control region. Analysis of mitochondrial DNA revealed that Oreochromis aureus exhibited the greatest number of polymorphic sites, with a total of 225, compared to Oreochromis niloticus and Oreochromis mossambicus, which had 129 and 84 polymorphic sites, respectively. The number of haplotypes was highest in O. niloticus with five, while O. aureus and O. mossambicus each had three haplotypes. O. niloticus also demonstrated the highest haplotype diversity (0.796), whereas O. aureus showed the highest nucleotide diversity (0.139). The largest genetic distance was found between O. aureus and O. mossambicus (0.388), whereas the smallest genetic distance was noted between O. niloticus and O. mossambicus (0.217). Enhancing tilapia production in Nigeria can be achieved by selectively breeding tilapia from the Itu, Ethiope, and New Calabar Rivers, which exhibited high genetic variation. [ABSTRACT FROM AUTHOR]

This study investigates the effects of the essential oil from Amomum villosum (EOA) on liver-protective effects in Nile tilapia (Oreochromis niloticus), utilizing a multidisciplinary approach that integrates physiological assessments and transcriptomic and metabolomic analyses. Fish were fed diets containing 2 g/kg of EOA over a 56-day trial, with a no-EOA diet serving as the control. The results demonstrate that EOA supplementation improves liver histology, enhances antioxidant capacities, and reduces inflammation in tilapia. The transcriptomic analysis revealed significant alterations in gene expression profiles related to RNA splicing, metabolism, and disease pathways. The identification of differential genes and disease databases identified key target genes associated with the primary component of EOA for its anti-hepatobiliary disease effects. Furthermore, a molecular docking analysis of EOA major components with core differentially expressed genes in the hepatobiliary syndrome indicated that α-pinene is a potential Hsp90 inhibitor, which may prevent inflammation. A metabolomic analysis further demonstrated that EOA supplementation leads to notable changes in liver phospholipids, fatty acids, and carbohydrate metabolism. These findings underscore the potential of EOA as a natural additive for improving liver health in tilapia, offering valuable insights to the aquaculture industry for enhancing fish health and welfare in intensive farming systems. [ABSTRACT FROM AUTHOR]

Abstract Aquaculture is an important component of the world food supply and a significant source of protein. However, this industry faces numerous problems. Including poor fish feed digestion and uneconomic nutrient utilization. This can result in unsatisfactory growth rates and poor stock performance. Utilizing probiotics, which are beneficial microbes that can enhance digestive systems and general fish health, is one possible way to address these issues. This study was designed to identify and evaluate a novel strain of Bacillus as a promising probiotic. The strain of Bacillus rugosus that was examined and coded NM007 showed promising probiotic characteristics that could help fish digest and utilize their feed more efficiently, reduce feed waste, and improve their digestive systems. B. rugosus NM007 exhibited the ability to produce digestive enzymes like protease, amylase, and lipase, which are the main digestive enzymes. It showed strong auto-aggregation activity and co-aggregation activity with Aeromonas sp. and Streptococcus sp. It also demonstrated tolerance to the presence of bile salt, acidic pH, and salinity up to 60 ppt. The sensitivity analysis towards antibiotics, hemolytic activity and the safety assessment on Nile tilapia fish (Oreochromis niloticus) confirmed the safety of this isolate. Based on the findings of this investigation and the isolate’s characterization, Bacillus rugosus NM007 could serve as a new promising probiotic bacterium for aquaculture.

The problem most often encountered in fish farming is disease which can cause a decrease in fish production levels. Parasites cause one of the infectious diseases found in fish farming. The presence of parasites can cause a decrease in the quality of the growth of fish production. The purpose of this study was to identify the prevalence of ectoparasites on Nile tilapia in Sidoarjo, Indonesia. Ninety-six samples from two ponds were examined under the microscope to find out the presence of ectoparasite that exists in the outside body part of the fish. Samples were collected from skin, fins, tail, and gills using native methods and observed under a microscope in the Division of Parasitology Laboratory, Faculty of Veterinary Medicine, Universitas Airlangga. The results of this study showed 86 samples positively infected by ectoparasite and 10 showed negative. The ectoparasites found in this study were Trichodina sp., Chilodonella sp., Ichthyophthirius multifillis, Gyrodactylus sp., and Dactylogyrus sp. The highest prevalence is Trichodina sp. and Dactylogyrus sp. The number of fish infested by ectoparasite is 89.56%, this is classified in the usual category. The highest prevalence occurs in infestations of Trichodina sp. i.e.72.91% which were contained in the 70 samples. While the lowest prevalence was in Gyrodactylus sp. by 8.32% in 8 fish samples. Double infections from two different ponds were 70% within 33 samples which were included in the usual category.

Abstract Microplastic (MP) ingestion through fish consumption is a concern for human exposure. While the presence of plastic particles in fish tissues has been documented worldwide, information on microplastic concentrations in edible tissues, especially those smaller than 10 µm, remains scarce. Spectrometric techniques provide a complementary analytical tool to measure MP mass for human exposure studies without intrinsic size limitations; however, their application to fish analysis is limited. In this study, we utilized pyrolysis gas chromatography–mass spectrometry (Py-GC–MS) for the identification and quantification of MPs in fish muscle tissues. Two sample preparation methods, pressurized liquid extraction, and chemical digestion, were tested for compatibility with Py-GC–MS analysis. An analytical method using chemical digestion was validated for analyzing particles ≥ 0.7 µm for 4 polymer types: polypropylene, polyethylene, polystyrene, and polymethyl methacrylate. The developed method was applied to 24 adult Nile tilapia (Oreochromis niloticus) samples from a recirculating aquaculture system. MPs were detected in 42% of the samples, with an average concentration of 0.14 ± 0.32 µg/g, while high variations within subsamples were observed. Our findings reveal trace amounts of MPs in edible fish tissues from aquaculture, highlighting the potential risk of microplastic ingestion through fish consumption. This underscores the need for further risk assessments to evaluate the impact on human health and to develop appropriate mitigation measures. Graphical Abstract