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Nile tilapia (Oreochromis niloticus) is valued in aquaculture because of its quick development and ability to thrive in various environments. Myxosporeans are among the fish parasites that affect fish productivity, as they impact fish growth and reproduction, resulting in large fish deaths in farms and hatcheries. This study has been focused on morpho-molecular identification for the myxosporean parasites infecting Nile tilapia from three governorates in Egypt and assessment of gene expression of different cytokines (Interleukin-1βeta (IL-1β), major histocompatibility complex class II (MHC-II), and clusters of differentiation 4 (CD-4) and 8 (CD-8)) in tissues. Additionally, this work aimed to correlate the developed histopathological alterations and inflammatory reactions in gills with immunohistochemical expression of inducible nitric oxide synthase (iNOS) and tumor necrosis factor-alpha (TNF-α). Finally, the infected fish's cortisol levels and blood glucose were assessed. Results of BLAST sequence analysis of the 18S rRNA for the collected protozoans confirmed Myxobolus agolus, M. brachysporus, M. tilapiae, and Henneguya species. The molecular characterization of the immunological status of gills revealed marked upregulation of different inflammatory cytokines in the gills of infected fish. There was a significantly increased serum cortisol and glucose level in infected fish compared with control, non-infected ones. Severe histopathological alterations were observed in the infected fish gills, associated with increased expression of iNOS and TNF-α and related to myxosporean infection. The present study provides new insights into oxidative stress biomarkers in Nile tilapia infected with Myxosporeans and elucidates the gill's immune status changes as a portal of entry for protozoa that contribute to tissue damage. [ABSTRACT FROM AUTHOR]

Aquaponics is a promising solution for addressing food security concerns. Nonetheless, an effective water-purification system is necessary to achieve high and stable yields of fish and vegetables. This study aimed to evaluate the nitrification and oxygen transfer performance of a laboratory-scale down-flow hanging sponge (DHS) reactor with a Brassica oleracea aquaponics system to treat water in an Oreochromis niloticus closed-aquaculture system. The DHS reactor showed a higher oxygen transfer coefficient (KLa) than the conventional aerator and provided an adequate dissolved oxygen (DO) concentration of approximately 5.5 mg/L essential for O. niloticus growth throughout the experimental period. The evaluated DHS-based aquaponic system maintained high water quality in an aquaculture tank, with a survival rate of 97%. The O. niloticusgrew at a low feed conversion ratio of 1.5–2.1 and a low feeding rate of 0.5% at high stocking densities of 17.5–22.2 kg-fish-weight/m3. 16S rRNA gene sequencing indicated that the DHS sponge carrier effectively retained nitrifying bacteria such as Nitrosomonas and Nitrospira. This study demonstrated that the DHS reactor provided a high DO concentration and that a simultaneous DHS reactor with a hydroponic tank provided a low-cost aquaponic system that could be applied for food production in the aquaculture industry. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effects of salinity on the proximate composition and fatty acid profile of the Nile tilapia fillet when reared in a biofloc system. Juveniles (200 ± 10 g) were reared at salinities of 2, 8, 15 and 22 PSU for 56 days. At the end of the experiment, the proximate composition and the fatty acid profile were evaluated in the fillets. No significant differences were observed for crude protein, ether extract, dry matter and ash levels. However, saturated (SFA) and monounsaturated (MUFA) fatty acids were higher in tilapia reared at 2 PSU compared to other salinities (8, 15, and 22 PSU). The polyunsaturated fatty acids (PUFA) contents did not vary among fish reared at salinities of 2, 8, and 15 PSU but were significantly lowest in tilapia reared at 22 PSU. The overall results suggest that the different salinities do not significantly affect the proximate composition of the Nile tilapia file reared in a biofloc system. On the other hand, the fatty acid composition was influenced by salinity, as a reduction in PUFA content was observed at the highest tested salinity (22 PSU) and an increase in SFA and MUFA contents were recorded at the lowest tested salinity (2 PSU). [ABSTRACT FROM AUTHOR]

The bioactive compounds of Artemisia annua have been used as feed supplements due to their pharmacological activities. The present study examined the effect of short-term feeding with a supplemented diet on the growth, feed efficiency, intestinal morphology, stress, immune system, and antioxidant biomarkers of juvenile Nile tilapia (Oreochromis niloticus) to evaluate the efficacy of using an alcoholic extract of A. annua (ae-Aa) as an additive in fish feed. Juvenile fish (200 fish, 30.43 ± 0.54 g) were distributed in 10 tanks (400 L, 20 fish/tank) corresponding to two treatments, each with five replicates. The fish were fed either a control diet (37% protein, 11% lipid: ae-Aa free) or an equivalent diet containing 0.5% ae-Aa to satiation for 15 days. Subsequently, blood, liver, and intestine samples were obtained from 10 fish per treatment group (2 fish per tank). Dietary supplementation with ae-Aa affected the leukocyte count (27.9 vs. 19.7 × 103 µL−1, ae-Aa group vs. control group), leukocyte respiratory activity (0.3 vs. 0.2 DO), and serum lysozyme concentration (28.1 vs. 22.4 ng dL−1) but not blood cells or the oxygen-carrying capacity. Treatment with ae-Aa reduced the plasma cortisol level (11.0 vs. 15.1 µL−1) but did not affect the levels of either glucose or chloride. Dietary ae-Aa influenced hepatic catalase (453.2 vs. 255.7 µmol H2O2 mg pt−1 min−1), glutathione-S-transferase (406.9 vs. 279.8 nmol mg pt−1 min−1), glutathione (4.5 vs. 2.9 nmol mg pt−1), and superoxide dismutase activity (22.4 vs. 20.1 U mg pt−1) and thus affected the antioxidant capacity, as reflected by reductions in lipid peroxidation (21.3 vs. 34.4 nmol mg pt−1) and DNA damage (26.7 vs. 32.2 µg DNA mg pt−1). Dietary ae-Aa increased the intestinal villus area and improved growth (body mass, 24.2 vs. 20.7 g; body length, 2.0 vs. 1.6 cm). Based on the above-described results, the administration of dietary ae-Aa, even for a short period, may have beneficial effects on immunity and oxidant defences and enhance the growth rate. [ABSTRACT FROM AUTHOR]

Survival analysis has proven to be a robust tool for studies in humans, and recently, it has been adopted in studies with animals, but very little in fish. The production of uniform fingerlings has been one challenge of aquaculture, influenced by the use of the efficient breeders. We aimed to present, for the first time in aquaculture, a survival analysis as a tool for decision-making by using the relationship between the main morphometric traits and the spawning time of Nile tilapia females up to 28 days after mating in an intensive system. We used 78 females and 26 males from which ten traits were evaluated. A check was made for the presence of eggs in the female mouth (spawning) every seven days until the final twenty-eight days. Confirmation of eggs was defined as uncensored data (C = 1) and absence of eggs as censored (C = 0). The Cox proportional hazards ratio and Kaplan–Meier models were adjusted to analyze the data. Females with a standard length of 19.19 cm (small group) and males with a weight of 259.14 g (small group) reproduced early, being more adapted to 1000 L tanks in a recirculation system. Less heavy egg masses were also related to early spawning. Therefore, the traits, standard length of the female, egg mass weight, and male weight, affected the presence of eggs up to 28 days and should be used as selection criteria for early breeders. Besides, the survival analysis was accurate as a tool for tilapia breeding management in an intensive system. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effect of supplementing feed with a functional mixture of immunomodulators, including β-glucans, nucleotides, ascorbic acid, and alpha-tocopherol, associated with a diet with lower levels of animal protein (11.5%) and higher levels of soybean meal (43.5%), on the zootechnical performance, health, hematological and immunological parameters, intestinal morphology, centesimal composition, and intestinal microbiome of juvenile Nile tilapia (initial weight 1.88 g ± 0.25 g, mean ± standard deviation). Two isocaloric and isoproteic diets (35% crude protein) were formulated, one with the inclusion of the immunostimulant functional mixture (40 kg·t−1), composed of 150 mg·kg−1 of nucleotides, 1000 mg·kg−1 of β-glucans, 1000 mg·kg−1 of ascorbic acid (vitamin C), and 20 mg·kg−1 of alpha-tocopherol (vitamin E), and another without. The combined supplementation of nucleotides, β-glucans, ascorbic acid, and alpha-tocopherol resulted in a 59.95% increase in final weight, 64% weight gain, 66% daily gain, a 21.31% decrease in feed conversion rate, and double the retention of body protein. Supplementation also improved intestinal morphology and modulated the intestinal microbiome, increasing Chao-1 diversity. Transmission electron microscopy confirmed that fish fed with both diets exhibited intact intestinal mucosal membranes. Supplementation did not alter the hematological and immunological parameters, suggesting that there was no overstimulation of the fish's immune system. This work allows us to evaluate the effect of reducing the use of animal protein in the diets of fish, along with the effects of nucleotides, β-glucans, ascorbic acid, and alpha-tocopherol. Together, these compounds can provide fish with the necessary tools to achieve optimal health and growth. [ABSTRACT FROM AUTHOR]

Different fertilization regimes in biofloc systems influence the predominance of distinct bacterial populations, impacting water quality and organism performance. This study evaluates the growth and nutrient absorption of the macroalgae Ulva lactuca when cultivated in an integrated system with Penaeus vannamei and Oreochromis niloticus in chemoautotrophic and heterotrophic systems. The experiment lasted 45 days and comprised two treatments, each with three replicates: chemoautotrophic—utilizing chemical fertilizers; heterotrophic—employing inoculum from mature biofloc shrimp cultivation, supplemented with organic fertilizers. Each treatment consisted of three systems, each containing a 4 m3 tank for shrimp, 0.7 m3 for tilapia, and 0.35 m3 for macroalgae, with continuous water circulation between tanks and constant aeration. Water quality analyses were carried out during the experiment, as were the performances of the macroalgae and animals. The data were subjected to a statistical analysis. Results revealed an increase in macroalgae biomass and the removal of nitrate (57%) and phosphate (47%) during cultivation, with a higher specific growth rate observed in the chemoautotrophic treatment. Nonetheless, the heterotrophic treatment exhibited higher levels of protein in the macroalgae (18% dry matter) and phosphate removal rates (56%), along with superior maintenance of water quality parameters. Tilapia performance varied across treatments, with a higher final weight and weight gain recorded in the heterotrophic treatment. The recycling of water from an ongoing biofloc cultivation with organic fertilization demonstrated viability for macroalgae cultivation within an integrated system involving shrimp and fish. [ABSTRACT FROM AUTHOR]

Accurate feeding management in aquaculture relies on assessing the average weight of aquatic animals during their growth stages. The traditional method involves using a labor-intensive approach and may impact the well-being of fish. The current research focuses on a unique way of estimating red tilapia's weight in cage culture via a river, which employs unmanned aerial vehicle (UAV) and deep learning techniques. The described approach includes taking pictures by means of a UAV and then applying deep learning and machine learning algorithms to them, such as convolutional neural networks (CNNs), extreme gradient boosting (XGBoost), and a Hybrid CNN-XGBoost model. The results showed that the CNN model achieved its accuracy peak after 60 epochs, showing accuracy, precision, recall, and F1 score values of 0.748 ± 0.019, 0.750 ± 0.019, 0.740 ± 0.014, and 0.740 ± 0.019, respectively. The XGBoost reached its accuracy peak with 45 n_estimators, recording values of approximately 0.560 ± 0.000 for accuracy and 0.550 ± 0.000 for precision, recall, and F1. Regarding the Hybrid CNN-XGBoost model, it demonstrated its prediction accuracy using both 45 epochs and n_estimators. The accuracy value was around 0.760 ± 0.019, precision was 0.762 ± 0.019, recall was 0.754 ± 0.019, and F1 was 0.752 ± 0.019. The Hybrid CNN-XGBoost model demonstrated the highest accuracy compared to using standalone CNN and XGBoost models and could reduce the time required for weight estimation by around 11.81% compared to using the standalone CNN. Although the testing results may be lower than those from previous laboratory studies, this discrepancy is attributed to the real-world testing conditions in aquaculture settings, which involve uncontrollable factors. To enhance accuracy, we recommend increasing the sample size of images and extending the data collection period to cover one year. This approach allows for a comprehensive understanding of the seasonal effects on evaluation outcomes. [ABSTRACT FROM AUTHOR]

Plastic pollution is one of today's most serious global issues in the aquatic environment and organisms, including entanglements, ingestion, and possible toxicity. The study was carried out to screen and identify the microplastics in some tissues of fish species from Sallari and Hauren Shanu burrow pits in Kano metropolis. A total of 60 fish samples comprising two species; Oreochromis niloticus (n = 30) and Tilapia zilli (n = 30), were collected from sampling sites (Sallari and Hauren Shanu). The fishes' gastrointestinal tract, gills and muscle tissues were collected, screenedand examined using a dissecting microscope for the presence of microplastics. Microplastics were found in all the examined fish tissue samples from both sites. In the samples from Hauren Shanu, 63% of the fish had microplastics in the gastrointestinal tract, 46% in muscle and 36% in the gills. In samples from Sallari, 33% of the fish had microplastics in theirgastrointestinal tract, 16% in muscle and 23% in the gills. Microplastics which include fibers, fragments, microbeads and tyre-dusts were observed in all the examined tissues of Oreochromis niloticus and Tilapia zilli although not significantly different (p > 0.05) between the fish species. The study demonstrates microplastics presence in the fish species and portrays to a large extent some degree of plastic contamination in Hauren shanu and Sallari burrow pits. Further assessments should be done on human food contamination by microplastics and their effects on human health. [ABSTRACT FROM AUTHOR]

Nile tilapia Oreochromis niloticus is one of the most important fishery resources and a valuable fish species for aquaculture programmes. It is found in almost all waters and is widely dispersed. Several natural populations of this species have been impacted by genetic pollution despite their significant economic relevance. Understanding population structure is a crucial first step in protecting this species in its native habitats as well as in choosing which wild stocks to use in hatchery initiatives. To demonstrate the genetic-population structure of this species, genetic differences among three geographically secluded populations of O. niloticus were investigated utilizing mitochondrial DNA cytochrome b gene sequences. The results were used to estimate the levels of genetic variability within and among the populations. The 56 cyt b (821 bp) sequences analysis revealed 21 haplotypes, with a nucleotide diversity of 0.0510 and a haplotype diversity of 0.881. In each of the populations, seven (7) singleton variable sites and 19 informative-parsimony sites, genetic diversity could be identified and few population haplotypes were found, indicating a minor genetic distinction between them. For the purpose of conservation and/or Nile tilapia breeding programmes, this information would assist in choosing the fish populations that maintain greater genetic variation in O. niloticus. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: The present study aimed to determine the growth, digestibility co-efficient, digestive enzyme activity and disease resistance of juvenile GIF tilapia fed with Ulva seaweed meal supplemented diet. Methods: The study was undertaken with different inclusion levels of Ulva seaweed meal (USM) such as raw (UR) and fermented (UF) Ulva meal (UR-5, UR-10, UR-15, UF-5, UF-10 and UF-15% of diet) and control feed (C) for a period of 60 days. Result: GIFT fed with fermented Ulva meal at a 10% inclusion level in their diet exhibited the highest growth performance (41.43 g) followed by UF5 (41.07±0.43 g), UR5 (39.65±0.36 g), control (39.09±0.20 g), UF15 (38.67±0.26 g), UR10 (38.47±1.47 g) and UR15 (35.77±0.35 g) diet. The highest apparent digestibility coefficient (ADC) with crude protein (85.14±0.91%) was observed in fishes fed with fermented Ulva meal at 10% inclusion rate than that of other treatments group for dry matter, ether extract and gross energy. The digestive enzymatic activities, amylase (0.029±0.00 units/mg protein/min), protease (0.147±0.0 units/mgprotein/min) and Lipase (0.273±0.05 units/mg protein/min), showed higher level in fishes fed with diet containing 10% fermented Ulva meal compared to other treatment groups including control. Moreover, at the end of the trial, increased survival rate (86.66%) was observed with fishes fed with Ulva based diets challenged against Aeromonas hydrophila. The histopathological study showed a lower level of infection in fishes fed with 10% fermented Ulva meal supplementation. The present study concluded that the requirement of Ulva meal in fish diet shows the following trend 10% of Ulva Fermented (UF) and UF-5, Ulva Raw (UR) 5%, control (C), UF-15, UR-10 and UR-15 diet that can improve the health status of the GIF tilapia. [ABSTRACT FROM AUTHOR]

Studies have emphasized that the presence of heavy metals in freshwater fish represents a global public health issue. Nigeria, being a developing nation with less emphasis on the quality of seafood consumed by the residents, ranks this study very vital. The policy implication of this study is the advancement of a healthy population in contemporary Nigeria. Hence, this study assessed heavy metal concentration in two fish species, Clarias gariepinus (Catfish) and Oreochromis niloticus (Nile Tilapia), in the Anambra River. The sample included twenty fishes, of which eighteen were collected from the three sampling locations (the fish ports of Anambra River), namely Otu-nsugbe, Otuocha, and Ikemivite) while two control samples were collected from a pond about 200 m away from the river. The levels of heavy metals were determined using Varian AA 240 atomic absorption spectrophotometer (AAS). The results showed that the concentrations of heavy metals (cadmium and arsenic) in the sampled fishes from Anambra River exceeded the joint World Health Organization and Food and Agriculture Organization (FAO/WHO) standard for fish and fish product consumption, while the concentration of chromium, mercury, and lead are within the permissible limit. The study also showed the distribution of the heavy metals in the fish organ varies among fish species. Heavy metals occur higher in Clarias garepinus than in Oreochromis niloticus, while tissue preference for heavy metal accumulation is in the order of gill > liver > muscle. It was recorded from this study that the heavy metal concentration in the fish from the pond is generally higher than the fish from the river for some metals. The high level of heavy metals in the sampled fish was attributed to heavy metals contamination of the river as a result of various anthropogenic activities such as mining, burning of fossil fuel and emission from the exhaust of boats/vehicles, overuse of fertilizers and pesticides, discharge of effluent, sewage, and hospital waste. This study concluded that long-term consumption of fish from the river may pose health risks to the consumers due to the possible bioaccumulation of heavy metals, especially cadmium and arsenic. It was recommended that continuous monitoring of heavy metal levels in the fish and water, public awareness, and appropriate legislative provisions should be put in place to ensure that harvested fish and fish products may be safe for human consumption. [ABSTRACT FROM AUTHOR]

Aquaculture is a key component of Ghana's food system strategies, promoting sustainable animal protein production. Aquaculture complements traditional marine capture fisheries to close the gap between demand and supply. However, about one third of fish produced globally have been reported to go to waste yearly. Among the various cultured fish, the Nile tilapia Oreochromis niloticus is a predominant species. This study aimed to estimate the extent of Nile tilapia wastage by consumers in Ghana. A web‐based cross‐sectional consumer survey was designed to assess the parts of the tilapia consumers generally classified as edible or inedible, taking into account the three primary tilapia preparation methods. The study utilised a semi‐structured online questionnaire, gathering responses from 246 participants. The parts of Nile tilapia investigated included the flesh, fins, offal, head, scales, bones, and gill flaps/opercula. The analysis of consumed and wasted parts of Nile tilapias by weight showed that, on average, the flesh made up the majority of the fish at 55.26%, followed by the head at 26.46%, offal at 8.51%, scales at 3.10%, fins at 2.93%, bones at 2.76%, and operculum at 0.98%, which was the smallest component. The study concluded that approximately 30%–45% of waste is generated from Nile tilapia in the Ghanaian supply chain. Tilapia was widely consumed by all groups, with an average liking score of 7.69 ± 1.95 on a 10‐point hedonic scale. A significant association was found between gender and consumption patterns with females showing a higher degree of liking. There was a strong association between the method of preparation and consumption patterns; the fried parts were classified as more edible compared to those that were boiled or grilled. To reduce waste in the aquaculture industry, tilapia and other fishes could be processed in a way that various edible and inedible parts are sold separately. Aquaculture is a key component of Ghana's food system strategies, promoting sustainable animal protein production. The aim of this study was to estimate the extent of Nile tilapia wastage by the consumer. A web‐based cross‐sectional consumer survey was designed to assess the parts of the tilapia consumers generally classified as edible or inedible. [ABSTRACT FROM AUTHOR]

Microalgae offer a sustainable source of omega − 3 fatty acids that can replace fish oil in aquafeeds, but the nutritional benefits are not always clear, particularly when microalgae are used as complete oil replacements in starter feeds. We compared the survival, growth, omega − 3 deposition and composition of the gut microbiota of juvenile mixed‐sex Nile tilapia (Oreochromis niloticus) that had been fed over a 3‐month period on six isonitrogenous, isolipidic and isocaloric aquafeeds that varied only on the contribution of fish oil, soya oil and microalgae (Schizochytrium) oil as lipid sources. Survival was not affected by diet, but fish fed a diet where the entire oil component (5%) was replaced by microalgae oil grew twice as fast as fish fed plant oil or a mixture of plant and fish oil. Dietary omega − 3 content was strongly correlated with omega − 3 deposition in the fish fillet. Complete replacement of fish oil by plant oil caused a significant decrease in the abundance of Peptostreptococcaceae and an increase in the abundance of Aeromonadaceae which is often associated with an inflammatory response in the fish gut. In contrast, when fish and soya oil in the reference diet were replaced by 100% microalgae oil, an increase in Mycobacteriaceae was observed. Our study indicates that Schizochytrium oil can be used to improve the growth of Nile tilapia and increase its omega − 3 content without any of the detrimental effects on the gut microbiome typically associated with some plant oil replacements. [ABSTRACT FROM AUTHOR]

In this study, the ability of a CC chemokine (On-CC1) adjuvant to enhance the efficacy of a formalin-killed Streptococcus agalactiae vaccine (WC) in inducing immune responses against S. agalactiae in Nile tilapia was investigated through immune-related gene expression analysis, enzyme-linked immunosorbent assay (ELISA), transcriptome sequencing, and challenge tests. Significantly higher S. agalactiae-specific IgM levels were detected in fish in the WC+CC group than in the WC alone or control groups at 8 days postvaccination (dpv). The WC vaccine group exhibited increased specific IgM levels at 15 dpv, comparable to those of the WC+CC group, with sustained higher levels observed in the latter group at 29 dpv and after challenge with S. agalactiae for 14 days. Immune-related gene expression analysis revealed upregulation of all target genes in the control group compared to those in the vaccinated groups, with notable differences between the WC and WC+CC groups at various time intervals. Additionally, transcriptome analysis revealed differential gene expression profiles between the vaccinated (24 and 96 hpv) and control groups, with notable upregulation of immune-related genes in the vaccinated fish. Differential gene expression (DGE) analysis revealed significant upregulation of immunoglobulin and other immune-related genes in the control group compared to those in the vaccinated groups (24 and 96 hpv), with distinct patterns observed between the WC and WC+CC vaccine groups. Finally, challenge with a virulent strain of S. agalactiae resulted in significantly higher survival rates for fish in the WC and WC+CC groups compared to fish in the control group, with a notable increase in survival observed in fish in the WC+CC group. [ABSTRACT FROM AUTHOR]

Tilapia farmers would benefit tremendously if they could decrease aggression among fish. Conspecific aggression affects the growth, feed conversion, and general well‐being of fish. Previous studies established an inverse relationship between blood cholesterol levels and aggression in fish, whereby a decrease in cholesterol led to an increase in aggression. The present study assessed the effect of an increase in dietary cholesterol on blood cholesterol and a possible decrease in the aggression of Nile tilapia oreochromis niloticus. Nile tilapia were stocked in an outdoor recirculation system and then offered one of five diets: 0% cholesterol, 0.5% cholesterol, 1% cholesterol, 1.5% cholesterol, and 2% cholesterol. Five fish of each treatment were moved to a glass tank and monitored for signs of aggression for 10 min, twice a day. This experimental procedure was repeated five times using a new set of fish every time. Results show an increase in cholesterol levels in the blood but that there are no significant differences in aggression among treatments. Accordingly, the present study suggests that an increase in dietary cholesterol increases blood cholesterol in fish but does not have a significant effect on antagonistic patterns in Nile tilapia. [ABSTRACT FROM AUTHOR]

Osun River is a major river in the Ogun-Osun River Basin and contributes significantly to fish production and quality source of protein. It is therefore essential to investigate the condition and characteristics of the most abundant fish species in the river. This aim of this study was achieved by investigating the Morphometric parameters, sex ratio, and condition factor of Oreochromis niloticus and Chrysichthys nigrodigitatus in the lower section of the river, because these fish species were the most abundant and economically important. Monofilament gillnets were used for fish sampling for twelve months to cover both wet and dry seasons (November 2017 to October 2018). A total of 1597 individuals of both species were collected comprising 40.14% O. niloticus samples and 59.88% samples of C. nigrodigitatus. The correlation coefficient (r) for O. niloticus and C. nigrodigitatus were 0.78 and 0.89 which indicated a high and very high relationship respectively. O. niloticus showed a significant negative allometric growth pattern (b = 2.315) while C. nigrodigitatus showed a growth pattern that was significant and positively allometric (b = 3.102). The mean condition factor (K) was 2.8 for O. niloticus and 1.9 for C. nigrodigitatus. The sex ratio of male to female was 1.5:1 for O. niloticus and 1.2:1 for C. nigrodigitatus. Both fish species responded well due to the high K-factor and good growth rate, and it is therefore essential to maintain optimal environmental factors for the sustainability of these fish species in the river. [ABSTRACT FROM AUTHOR]

Oreochromis niloticus a Nile tilapia fish is widely used for fish culture practice in many countries for its easy acclimatization and high yield at a short pace of time. Selenium‐chitosan (SeCh) nanoparticles are efficiently used in agriculture, medicine, and aquaculture practices in several studies. The significant approach of Selenium‐Chitosan incorporated fish feed will be evaluated in the present study to achieve the better aquaculture practice in future. In the present study, SeCh nanoparticle was chemically synthesized and incorporated with formulated fish feed. Selenium formulated fish feed contains 31.49 g of carbohydrates and 41.52 g of proteins. SeCh‐fed O. niloticus fingerlings exhibited significantly increased specific growth rates in terms of weight gain, and feed conversion ratio. Chemical characterization of SeChNPs through FTIR spectroscopy indicates the presence of an adjuvant combination of selenium and chitosan presence through functional groups of COO stretch, CH, CC, and CN stretch representing at 3226, 2878, and 1734 cm−1, respectively. Scanning electron microscopy (SEM) and EDX analysis revealed the structural properties of SeChNPs as a fibrous pattern that contains Carbon, Oxygen, and Selenium elements as predominant peak values. SeChNPs incorporated fish feed has higher protein content which is a standard hallmark for a fish feed and an essential prerequisite for fish growth. The formulated SeCh fish feed in the present study is an innovative approach which can be taken further for higher level testing and processing for developing as a better fish feed in terms of feasible and efficient fish growth enhancer. [ABSTRACT FROM AUTHOR]

In this study, the ability of the Quick-DNA™ Tissue/Insect Miniprep Kit and Chelex® methods to extract DNA from O. niloticus skin, muscle, and gill tissue was compared. The quantity and purity of the DNA were measured with a NanoDrop spectrophotometer. Based on the results obtained, it appears that the DNA extracted using the Kit has good quality based on A260/280 (1.67–1.98), and the Chelex method (1.52-1.81) was acceptable. ANOVA for the amount of nucleic acid revealed a significant difference between muscle and skin with gill tissue (P < 0.05). However, the skin of O. niloticus subjected to both methods was the best at extracting DNA (1.89-1.81). The extracted DNA was also studied by 28S ribosomal DNA and COI of mitochondrial DNA genes. Phylogenetic analysis based on 28S rDNA and COI of mtDNA placed the South African population of O. niloticus in a clade with other related species with a posterior probability value of 1.00. Finally, the molecular results showed that 28S ribosomal DNA is a suitable marker for the identification of O. niloticus. In conclusion, precise identification of O. niloticus is critical for breeding for farmers and commercial sectors. [ABSTRACT FROM AUTHOR]

This study aimed to explore the effects of Bacillus amyloliquefaciens (BA) as one woody forage addition (as a probiotic, 1 × 107 CFU/g) on tilapia (Oreochromis niloticus). Woody forage is one kind of fishery feed that could significantly enhance the growth, feed utilization, and digestibility of tilapia. At first, tilapia was divided into eight groups and fed with control, control + BA, Moringa oleifera, M. oleifera + BA, Neolamarckia cadamba, N. cadamba + BA, Broussonetia papyrifera, and B. papyrifera + BA diets, respectively. After dieting for 8 weeks, the intestinal morphology of tilapia in the eight groups was observed, and the effects of the B. amyloliquefaciens addition and wordy forage on the intestine functions were analyzed by two-way ANOVA. As no significant negative effects were found on the woody forage on tilapia, the villus height, density and width, and epithelial goblet cells in the posterior intestines of tilapia with BA supplementation were greater than those in the groups without BA supplementation, suggesting B. amyloliquefaciens SCAU-070 could promote the growth and development of tilapia intestinal tracts. Furthermore, it was found that B. amyloliquefaciens SCAU-070 enhanced the antioxidation capacity of tilapia posterior intestine tissue by promoting the activity of superoxide dismutase and content of malondialdehyde. In addition, the result of high-throughput sequencing (16S rDNA) showed that the beneficial bacteria Cetobacterium and Romboutsia in the probiotic groups increased significantly, while the potential pathogenic bacteria Acinetobacter decreased significantly. [ABSTRACT FROM AUTHOR]

This study aimed to use common mallow (Malva sylvestris) extract (EMS) with ratios of 0.0, 0.5, 1.0, and 2.0% as an indicator in the film produced from corn starch/tragacanth gum matrix using a casting method to monitor the freshness of Nile tilapia fillets stored at 4 °C. The results showed that the total anthocyanin content of EMS was 1185.6 ± 0.58 mg cyanidin-3-glucoside Kg−1. The starch/tragacanth gum films incorporated with 0.5 and 1.0% EMS were sensitive to the 0.8 and 1.4 M ammonia and their color changed after 20 min of exposure, while starch/tragacanth gum film incorporated with 2.0% EMS showed no visible color change in the presence of 0.2, 0.8 and 1.4% M ammonia. The Fourier transform infrared and X-ray diffraction spectra of the colorimetric films showed that EMS was successfully immobilized into the starch/tragacanth gum matrix. The moisture content and water solubility were significantly lower in the films containing EMS compared to those with no EMS supplementation. With increasing EMS concentration, water vapor permeability and ultimate tensile strength significantly decreased with the lowest values observed in films incorporated with 2.0% EMS (p < 0.05). The color of the starch/tragacanth gum films incorporated with 0.5 and 1.0% EMS was changed with a decrease in the quality and freshness of Nile tilapia fillet from pink to green and gray, respectively, after 12 days of storage at 4 °C. Findings of the present study illustrated that the pH-sensitive starch/tragacanth gum film incorporated with 0.5–1.0% EMS could be used as a halochromic indicator in the smart packaging of Nile tilapia fillet. [ABSTRACT FROM AUTHOR]

The present study aims to evaluate the potential effects of cyanobacteria on water quality parameters and Oreochromis niloticus in the fish ponds at Al-Abbassa Fish Hatchery, Sharkia Governorate, Egypt. The study identified five cyanobacterial genera: namely, Anabaena, Gleotrichia, Lyngbya, Oscillatoria and Phormidium. Oscillatoria sp. was the dominant genus in the selected fish ponds. Physico-chemical parameters of water samples showed significant variations during the four seasons. Anabaena sp. extract had the most toxic effect on the survival rate of O. niloticus after 72 h of exposure. Biochemical parameters of collected O. niloticus fish significantly increased compared to the control group. We concluded that the detected cyanobacterial genera in the fish ponds affected water quality and O. niloticus fish. [ABSTRACT FROM AUTHOR]

Objective: During Egypt's hot summer season, Aeromonas veronii infection causes catastrophic mortality on Nile Tilapia Oreochromis niloticus farms. Egypt is ranked first in aquaculture production in Africa, sixth in aquaculture production worldwide, and third in global tilapia production. This study aimed to investigate, at the molecular level, the early innate immune responses of Nile Tilapia to experimental A. veronii infection. Methods: The relative gene expression, co‐expression clustering, and correlation of four selected immune genes were studied by quantitative real‐time polymerase chain reaction in four organs (spleen, liver, gills, and intestine) for up to 72 h after a waterborne A. veronii challenge. The four genes studied were nucleotide‐binding oligomerization domain 1 (NOD1), lipopolysaccharide‐binding protein (LBP), natural killer‐lysin (NKL), and interleukin‐1 beta (IL‐1β). Result: The four genes showed significant transcriptional upregulation in response to infection. At 72 h postchallenge, the highest NOD1 and IL‐1β expression levels were recorded in the spleen, whereas the highest LBP and NKL expression levels were found in the gills. Pairwise distances of the data points and the hierarchical relationship showed that NOD1 clustered with IL‐1β, whereas LBP clustered with NKL; both genes within each cluster showed a significant positive expression correlation. Tissue clustering indicated that the responses of only the gill and intestine exhibited a significant positive correlation. Conclusion: The results suggest that NOD1, LBP, NKL, and IL‐1β genes play pivotal roles in the early innate immune response of Nile Tilapia to A. veronii infection, and the postinfection expression profile trends of these genes imply tissue‐/organ‐specific responses and synchronized co‐regulation. Impact statementWe tracked the early responses of four innate immunity genes (NOD1, LBP, NKL, and IL‐1β) in the spleen, liver, gills, and intestine of Nile Tilapia for up to 72 h after infection with Aeromonas veronii. The gene expression trends and the specific tissue/organ responses revealed a dynamic and coordinated co‐regulation. These findings provide valuable preliminary insights into the intricate immune mechanisms underlying the response of Nile Tilapia to A. veronii infection and may extend to other similar gram‐negative bacterial pathogens. [ABSTRACT FROM AUTHOR]

The present research evaluates the performance of the Nile tilapia (Oreochromis niloticus) (initial weight 11.5 ± 0.07 g) with biofloc technology. For this purpose, spent grains (malted barley) from the brewing industry after aerobic fermentation were used, as both a carbon source (suspended solids) and partial substitute for the diets at 0, 10, 20, 30, and 40% levels (settleable solids). The partial 20% substitution of the diet did not have significant effects on the biological parameters: final body weight, weight gained, average body weight, specific growth rate, daily growth index, condition factor, feed conversion ratio, protein efficiency rate, and viscerosomatic and hepatosomatic indices. However, the dietary substitution showed a significant effect on the final biofloc chemical composition. Nitrogen compounds, NH4+, NO2−, and NO3−, were adequate for tilapia cultivation in all the treatments. No clear effect of partial dietary substitution was observed on meat quality parameters: pH, color, water holding capacity, and amino acid and fatty acid profile of fillet. The results suggest that a 20% substitution of the diet for malted barley is suitable for satisfactory biological parameters and Nile tilapia fillet quality. [ABSTRACT FROM AUTHOR]

This study was conducted to determine the effect of vitamin C supplementation on the survival rate and histopathological changes of gills and kidneys of tilapia infected by Aeromonas hydrophila. Three doses of vitamin C were tested (150; 300; and 450 mg/kg) with two control groups. Tilapia with uniform size (average weight of 14 grams) as the criteria for inclusion were randomly distributed in five ponds with 15 tilapia fish per pond. Tilapia was fed with hands until full for two weeks. Tilapia was then infected with A. hydrophila to find out the survival rate and histopathological changes of gills and kidneys at the end of the experimental period or 7 days after infection. The supplementation of 150 mg/kg vitamin C in feed increased Tilapia's survival rate (%) by 86.67% or higher than other treatment and control groups. The damage to gills in terms of lamella separation was found in all treatment groups and kidneys. The results found that the supplementation of 150 mg/kg vitamin C in feed increased survival rate but did not give effective protection on gills and kidneys. [ABSTRACT FROM AUTHOR]

The present investigation proposed an innovative trial at the probable beneficial effects of nano-Bacillus amyloliquefaciens (NBA) dietary incorporation on the Nile tilapia (Oreochromis niloticus). The investigation included the impact on the growth, digestive functions, immune-antioxidant indices, and resistance to Aeromonas hydrophila challenge. A total of 135 fish (35.14 ± 0.12 g) were equally allocated into three groups (45 fish/group; 15 fish/replicate) in triplicates for 70 days. The control, NBA2, and NBA4 groups were fed basal diets enriched with 0, 102, and 104 CFU/kg NBA, respectively. Following the feeding experiment, all experimental groups were injected with 0.1 mL (1.5 × 106) A. hydrophila, and the fish mortalities were observed for 14 days. The outcomes showed that dietary NBA (NBA4 followed by the NBA2 diet) augmented the growth variables (final body weight, total weight gain, and specific growth rate) and condition factor and declined the feed conversion ratio. The intestinal digestive enzyme (amylase and lipase) and growth hormone levels were increased and the serum glucose level was decreased by dietary NBA. Furthermore, NBA diets enhanced the immune (total protein, globulin, lysozyme, complement 3, myeloperoxidase, and phagocytic activity) and antioxidant (superoxide dismutase, catalase, and total antioxidant capacity) parameters. The intestinal histology revealed no pathological lesions with a significant improvement in the intestinal histomorpho-measures (villus height and width, villus surface area, lamina propria thickness, and tunica muscularis thickness) by NBA diets in a dose-dependent manner. In the fish intestine, the B. amyloliquefaciens count was increased in the NBA groups (NBA4 group followed by NBA2 group) with no discernible difference in the total bacterial count. Fish resistance to the A. hydrophila challenge was increased by increasing the survival % in the NBA4 group (91.70 %) followed by the NBA2 group (83.30 %) compared to the control group (70.80 %). Overall, dietary NBA (especially 104 CFU/kg diet) could be a promising feed supplement in the Nile tilapia diets for improving their growth, health, and resistance to bacterial challenges.

In recent years, microplastics (MPs) have emerged as a prominent environmental problem in waters and environments, including lake waters. Microplastics in freshwater, such as those in floating net cages (FNC), can be consumed by Nile tilapia (Oreochromis niloticus), one of the commercially available cultivated fish in Indonesia. This study aims to determine the prevalence of microplastics and compare their characteristics in the surface water, flesh, and gastrointestinal tract (GIT) of Nile Tilapia (O. niloticus) at Lake Ranu Grati, Pasuruan, East Java, Indonesia. Visual characteristics of MPs were observed using a stereo microscope, and polymers were analysed by ATR-FTIR (Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy). The abundance of MPs from water sample locations in Lake Ranu Grati reached 1116 MPs particles. In the water samples, the inner and outer sides of the FNC are dominated by the MPs with a size range of 251–500 µm and 1001-2000 µm in the milieu of Ranu Grati Lake. The most common MPs' types and colours are fibre and black, dominated by Polyethylene (PE). In 25 O. niloticus samples, 576 particles of MPs were found in the flesh and 724 particles in the gastrointestinal tract (GIT). This study found no significant variation in microplastic abundance between flesh and GIT samples (p>0.05; Mann-Whitney U test). Microplastics in Nile Tilapia flesh samples were dominated by blue fibres with a size range of 101–250 µm, and the polymer found was PA (polyamide). Meanwhile, in the GIT samples, microplastics were dominated by black fibre, with a size range of 251–500 µm, and the polymer found was PA (polyamide).

Background Nile tilapia (Oreochromis niloticus) is predominant cultured species in aquaculture. However, there is a scarcity of literature regarding relationship between guava and star gooseberry leaf extract and the condition factor. Thus, the present study aims to investigate the effect of guava and star gooseberry leaf extract-supplemented diets on the specific growth rate, length-weight relationship, and condition factor of Nile tilapia. Methods Six hundred and thirty Nile tilapia (8.7±0.4 g) were randomly distributed among twenty-one tanks (30 fish per tank) within a recirculation system. Over a 60-day period, the fish were fed diets supplemented with 5g/Kg and 10g/Kg of guava leaf extract (GLE-5, GLE-10), star gooseberry leaf extract (SGLE-5, SGLE-10), and a mixture of both (MxLE-5, MXLE-10). Subsequently, specific growth rate, length-weight relationship, and condition factor were determined. Results After 60 days, the specific growth rate was significantly higher in all the GLE, SGLE, and MxLE groups compared to the control group. The final lengths and weights differed significantly both in the control group and all the GLE, SGLE, and MxLE groups. The analysis of the regression equation indicated a positive correlation (r = 0.970, 0.977, 0.976, 0.974, 0.974, 0.974, and 0.969) between the length and weight of Nile tilapia in the control group and in all the GLE, SGLE, and MxLE groups. The regression exponent “b” values in all the GLE, SGLE, and MxLE groups were >3, indicating a positive allometric growth pattern in Nile tilapia compared to the control (b=2.866), which exhibited a negative allometry. The final condition factor values did not differ significantly in either the control group or any of the plant extract groups. Conclusions Nile tilapia exhibited positive allometric growth patterns and maintained good health when fed with GLE, SGLE, and MxLE groups. Therefore, these plant extracts demonstrate suitability for commercial Nile tilapia production.

River pollution can harm human health through direct contact, drinking water, and the consumption of contaminated fish and irrigated agricultural products. Surface water and Nile tilapia (Oreochromis niloticus) samples were collected monthly from July 2022 to June 2023 at three sites (El-Rahawy, Sabal, and Tala) along the Rosetta Nile branch in Egypt to monitor the presence of eight trace elements. The potential human health risks from consuming contaminated fish were also assessed. Iron and manganese were consistently detected in all water samples across most seasons and locations, with concentrations generally below the WHO permissible levels. All 72 analyzed fish muscle samples were found to contain trace elements. The mean concentrations of metals in the fish muscle samples, in descending order, were: iron > zinc > copper > manganese > tin > antimony > lead > mercury. Significant spatial and seasonal variations were observed in both water and fish samples. El-Rahawy was identified as the most contaminated site, with summer exhibiting the highest contamination rate compared to other seasons. Fish samples collected from El-Rahawy demonstrated the highest bioconcentration factor (BCF) values for most elements, particularly mercury, lead, iron, manganese, and antimony. Target hazard quotient (THQ) calculations for the trace elements in Nile tilapia muscles revealed that all trace elements, except antimony, had THQ values below 1, suggesting that consuming Nile tilapia from these sites is unlikely to cause adverse health effects. However, THQ values for antimony exceeded the threshold of 1, indicating a potential health risk for consumers. Although the detected trace elements in the fish were below the permissible toxicity limits, some could pose a future threat to human health, necessitating further studies, ongoing monitoring, and preventive measures.

Abstract This study examines the use of dragon fruit peel (DFP) powder as a dietary supplement on growth performance, immune responses, and gene expression of Nile tilapia, Oreochromis niloticus, cultured within biofloc systems. A total of 300 Nile tilapia fingerlings (14.64 ± 0.09 g) were subjected to five dietary treatments, with DFP added to a basal diet at doses of 0, 20, 40, 80, and 160 g kg−1 DFP. Growth and immunological responses were assessed after 4 and 8 weeks of feeding, and the transcriptional level of immune and antioxidant‐related genes was measured after 8 weeks. Fish fed diets containing DFP exhibited significantly greater weight gain, faster growth, and enhanced levels of key indicators of immunity than control fish (p

As a germ-cell-specific maternal mRNA and RNA binding protein, dead end (dnd1) plays an important role in migration and maintenance of primordial germ cells (PGCs), and therefore, disruption of dnd1 results in no germ cells. However, the effect and duration of maternal dnd1 on PGCs in zygote mutants have not been reported yet. In the present study, CRISPR/Cas9 was used to mutate dnd1 in tilapia. Supported by the maternal dnd1 mRNA, germ cells of the dnd1 homozygous mutants proliferated and migrated normally before 7 dpf (days post fertilization). After the degradation of maternal dnd1 mRNA, significant downregulation of piwil1, piwil2, nanos2, nanos3 and vasa mRNA, and blocked migration of germ cells were observed at 14 dpf. In dnd1 zygote mutants, the number of germ cells was decreased significantly compared with wild type (WT) at 25 dpf, and no germ cell was observed at 30 dpf. Consistently, no expression of vasa and nanos3 was detected in the adult dnd1 mutants by qPCR. Interestingly, Cyp19a1a/cyp19a1a and foxl2 were expressed in dnd1-deficient XX gonads, while Cyp11c1/cyp11c1 and dmrt1 were expressed in dnd1-deficient XY gonads as in WT gonads. Correspondingly, both serum E2 level in XX and 11-KT level in XY fish did not differ significantly between dnd1 mutant and WT fish. Taken together, the present study demonstrates that disruption of dnd1 lead to progressive loss of germ cells, while the somatic cells are not affected in tilapia. The sexual fate of gonads is determined by the genetic sex instead of germ cell number, which makes tilapia a potential surrogate model for germ cell transplantation.

This study investigated the use of black soldier fly (Hermetia illucens) larvae (BSFL), provided in either full-fat (FBSF) or defatted (DBSF) forms, as an alternative protein source in the diet of Nile tilapia (Oreochromis niloticus) fingerlings. Specifically, the influence was assessed of BSFL on growth performance, hematological parameters, body composition, and histology. Nine diets (including the control) were formulated to be isonitrogenous (35 % crude protein) and isolipidic (6 % crude lipid), relying on fish meal as the primary protein source and gradually replacing it with BSFL meal at levels of 25 %, 50 %, 75 %, or 100 % on an equivalent protein basis, corresponding to dietary inclusion levels of 5.25 %, 10.25 %, 15.5 %, and 20.0 %, respectively. Fish with an initial mean weight ± standard deviation of 1.3 ± 0.26 g were fed for 12 weeks until the fish final weight was in the range 24.08–34.95 g. Based on the results, there were no significant (p>0.05) differences in the growth performance or feed conversion ratios among the treatments. Additionally, there were no significant differences in the hematological responses or the proximate body composition. Furthermore, 100 % substitution of fish meal with FSFL and DBSF meal caused blood congestion in the hepatopancreas region and several intraepithelial leukocytes in the intestine. There were no detrimental impacts at levels of 25 %, 50 %, and 75 % on growth performance, hematological responses, body composition, or the intestines or liver histological characteristics of the O. niloticus fingerlings. This information should provide useful guidance for the management of Nile tilapia, an economically important species.

Abstract This study investigated the effects of dietary supplementation with the product Hilyses on growth performance, feed utilization, nutrient composition, hematological parameters, serum biochemistry, immune function, antioxidant status, and digestive enzyme activity in juvenile Nile tilapia (Oreochromis niloticus, initial body weight 4.24 ± 0.01 g). The fish were fed diets supplemented with Hilyses at concentrations of 0, 1, 2, or 3 g/kg for a period of 8 weeks. The results showed that supplementation with Hilyses at levels up to 2 g/kg diet significantly improved final body weight, weight gain, specific growth rate, feed efficiency ratio, protein efficiency ratio, apparent protein utilization, and energy utilization compared to the control diet without Hilyses. Carcass crude protein content and moisture were significantly higher in Hilyses-fed groups, while crude lipid content decreased at the 3 g/kg supplementation level. Hilyses supplementation enhanced various hematological parameters, including increased red blood cell count, total leukocyte count, hemoglobin concentration, hematocrit, and mean corpuscular volume. Serum biochemistry and immune function markers like total protein, albumin, complement component C3, IgM, and IgG were significantly elevated in the 2 and 3 g/kg Hilyses groups. Antioxidant enzyme activities (catalase, glutathione peroxidase, total superoxide dismutase) were enhanced, and lipid peroxidation was reduced, in the 2 g/kg Hilyses group. Digestive enzyme activities, particularly protease and lipase, were also improved with Hilyses supplementation. Histological examination showed reduced lipid deposition in the liver and increased branching of intestinal villi at the 2 g/kg Hilyses level. Overall, these results indicated that dietary Hilyses supplementation at 2 g/kg diet optimizes growth, feed utilization, nutrient composition, hematology, immunity, antioxidant status, and digestive function in juvenile Nile tilapia.

Abstract Background Moringa oleifera, a well-known medicinal plant, has been used in aquafeed as a dietary supplement. Based on previous studies, insufficient research is available on the dietary supplementation of Nile tilapia with M. oleifera leaf and seed mixtures, specifically the fermented form. Therefore, this study aimed to investigate the efficacy of fermented (FMO) versus non-fermented M. oleifera (MO) leaf and seed mixtures on immunological parameters, antioxidant activity, growth performance, and resistance to A. hydrophila infection after a 30-day feeding trial on Nile tilapia. Methods A total of 180 fingerlings were randomly divided into four groups in addition to the control group (36 fish each, in triplicate). Fish in the tested groups were fed on basal diet supplemented with MO5%, MO10%, FMO5%, and FMO10%, while those in control were fed on basal diet only. After the feeding trial, fish were challenged with A. hydrophila. The immunomodulatory activity of M. oleifera was evaluated in terms of phagocytic and lysozyme activities, immune-related cytokines and IgM gene expression. Antioxidants, and growth-promoting activities were also assessed. Results The results revealed that fish supplemented FMO markedly in FMO10% group followed by FMO5%, exhibited significant (P

Abstract Context Recently, prioritize has been given to using natural phytogenic or nano compounds as growth promoters and immunostimulants in fish diets as an alternative to antibiotics. Aims The main propose of this trial was to determine the impact of supplementing diets with spirulina or curcumin nanoparticles on the performance and health indicators of Nile tilapia fingerlings. Methods In a 56-day feeding trial, 180 tilapia fingerlings were assigned into three main groups, as follows: 1st, control group, 2nd, Spirulina platensis (SP; 5 g kg-1 diet) and 3rd, curcumin nanoparticles (CUR-NPs; 30 mg kg-1 diet). Key results Incorporating tilapia diets with SP or CUR-NPs significantly improved performance, body chemical analysis, blood biochemical and hematological indices, digestive enzyme activities, and antioxidant and immunostimulant features compared to the control. Conclusion Fortified tilapia diets with CUR-NPs or SP efficiently boost the productivity and health of Nile tilapia fingerlings. Implications The research introduces new practical solutions for applying safe feed additives as alternatives to antibiotics in tilapia farming.

The study was conducted at Lake Hayq, one of the lakes of Wollo, Ethiopia. Data were collected at the landing sites for 365 days (June 8, 2022 to June 7, 2023). The basic information gathered in the fishing part of the Lake was Nile tilapia caught by fishermen, the total number of tilapia and the increase in fishing effort. The aim of the research was to estimate the size of the Nile tilapia population and the fishing mortality rate in length groups for Nile tilapia stocks occurring in the lake. A Jones length-based cohort analysis model was used to estimate Nile tilapia population. The estimated Nile tilapia population was over 46.8 Million tilapia per year. The model estimates that more than 13.3 million 8-10 cm Nile tilapia are caught in fisheries each year.

Abstract Polystyrene nanoplastic (PS-NPs) and Engine oil (EO) pose multiple ecotoxic effects with increasing threat to fish ecosystems. The current study investigated the toxicity of 15 days exposure to PS-NPs and / or EO to explore their combined synergistic effects on Nile tilapia, Oreochromis niloticus (O. niloticus). Hematobiochemical parameters, proinflammatory cytokines, and oxidative stress biomarkers as well as histological alterations were evaluated. The experimental design contained 120 acclimated Nile tilapia distributed into four groups, control, PS-NPs (5 mg/L), EO (1%) and their combination (PS-NPs + EO). After 15-days of exposure, blood and tissue samples were collected from all fish experimental groups. Results indicated that Nile tilapia exposed to PS-NPs and / or EO revealed a significant decrease in almost all the measured hematological parameters in comparison to the control, whereas WBCs and lymphocyte counts were significantly increased in the combined group only. Results clarified that the combined PS-NPs + EO group showed the maximum decrease in RBCs, Hb, MCH and MCHC, and showed the maximum significant rise in interleukin-1β (IL-1β), and interleukin-6 (IL-6) in comparison to all other exposed groups. Meanwhile, total antioxidant capacity (TAC) showed a significant (p

Abstract Background Pseudomonas putida is a pathogenic bacterium that induces great losses in fishes, including Nile tilapia (Oreochromis niloticus). Currently, the application of nanomaterials in aquaculture practices has gained more success as it endows promising results in therapies compared to traditional protocols. Objective Therefore, the current perspective is considered the first report to assess the anti-bacterial efficacy of titanium dioxide nanogel (TDNG) against Pseudomonas putida (P. putida) in Nile tilapia. Methods The fish (n = 200; average body weight: 47.50±1.32 g) were allocated into four random groups (control, TDNG, P. putida, and TDNG + P. putida), where 0.9 mg/L of TDNG was applied as bath treatment for ten days. Results Outcomes revealed that P. putida infection caused ethological alterations (surfacing, abnormal movement, and aggression) and depression of immune-antioxidant variables (complement 3, lysozyme activity, total antioxidant capacity, superoxide dismutase, and reduced glutathione content). Additionally, a substantial elevation in hepatorenal biomarkers (aspartate and alanine aminotransferases and creatinine) with clear histopathological changes and immuno-histochemical alterations (very weak BCL-2 and potent caspase-3 immuno-expressions) were seen. Surprisingly, treating P. putida-infected fish with TDNG improved these variables and obvious restoration of the tissue architectures. Conclusion Overall, this report encompasses the key role of TDNG as an anti-bacterial agent for controlling P. putida infection and improving the health status of Nile tilapia.

Nile tilapia is the most farmed freshwater fish species across vast areas of the African continent. Although Egypt is considered the largest African producer of Nile tilapia, this fish has been faced with frequent episodes of mortality at both hatchery and farm levels. In the present study, we conducted field screenings to identify the major bacterial pathogens responsible for these mass kills among broodstocks and seeds in Egyptian hatcheries. Aeromonas hydrophila and Streptococcus agalactiae were determined to be the major bacterial threats to hatchery-reared Nile tilapia. The bacterial isolates were presumptively identified using conventional biochemical tests and the API 20 NE miniaturized test. The final identities of the retrieved bacterial isolates were molecularly confirmed using PCR and sequencing of 16S rRNA genes. A. hydrophila and S. agalactiae isolates were found to be sensitive to florfenicol, while the two isolates exhibited resistance to novobiocin and ampicillin. The A. hydrophila isolates were confirmed to be sensitive to oxytetracycline, whereas the S. agalactiae isolates were sensitive to erythromycin. Histopathological examination of the livers of infected fish revealed vacuolar degeneration and necrosis of hepatocytes. Remarkably, infiltrations of Gram-positive cocci were documented within hepatic parenchyma and brain tissues. Further, the infected fish exhibited edematous brains with inflammatory cell infiltration through the meninges. Severe retinal pathology, including collagen fibre disorganization, oedema, and inflammatory cell infiltration was also detected. The current study emphasizes the deleterious impacts of some ubiquitous bacterial pathogens on the health status of Nile tilapia broodstocks and their seeds. Ultimately, we affirm that regular monitoring of water quality, feed quality, proper handling of broodstocks, and accurate diagnosis is a crucial asset in preventing disease spread and mass fish kills in Egyptian hatcheries.

This study evaluated the effect of replacing fish meal (FM) with black soldier fly (Hermatia illucens) larvae meal (BSFLM) on growth performance and economic efficiency of Nile tilapia (Oreochromis niloticus) production. The BSFLM replaced FM at 0, 25, 50 and 75% (T1, T2, T3, and T4, respectively). One thousand two hundred (1,200) all-male Nile tilapia fry were stocked in twelve hapas at Kenya Marine and Fisheries Research Institute (KMFRI), Sangoro aquaculture research station in Kenya, and hand-fed four times daily for 21 weeks. Thirty (30) fish were sampled biweekly from each hapa for measurement of total length and weight. Findings indicated that diet T3 outperformed all the other treatments in respect to final body weight (23.20 ± 1.15 g), daily weight gain (0.13 ± 0.02 g), final weight gain (23.09 ± 1.15 g), survival rate (96.74 ± 3.18 %), SGR (1.31 ± 0.03 % day-1), FCR (1.57 ± 0.02), feed efficiency (0.64 ± 0.02), and condition factor (1.92 ± 0.01). The cost per kilogram of feed was highest for control diet (USD 0.91) and lowest for 75% BSFLM diet (USD 0.79). Economic Conversion Ratio (ECR) was lowest for the 50% BSFLM diet (1.26 ± 0.14) and highest for the control diet (1.44 ± 0.14). Economic Profit Index (EPI) was highest for the 50% BSFLM diet (141.82 ± 7.88) and lowest for the 25% BSFLM diet (106.64 ±6.63). The findings reveal that 50 to 75% BSFLM inclusion is an ideal replacement for FM in Nile tilapia diets, and is technically and economically efficient for Nile tilapia production. [Fundam Appl Agric 2024; 9(1.000): 1-9]