Search Results (16)

The effect of increased corrosion in re-enforcement structures has led to the need to identify and develop more inexpensive, non-toxic, eco-friendly and readily available inhibitors from natural resources. Extensive research and development have led to the discovery of new classes of green corrosion inhibitors. In this work, Tilapia fish scales (FSs) were used as a green corrosion inhibitor as they are abundant in both organic components, such as collagen (C₁₂H₁₉N₃O₅), and inorganic components, such as hydroxyapatite (Ca₁₀(PO₄)₆(OH)₂). The FSs were subjected to a maceration process to extract all the inorganic and organic compounds. The FS extract was then characterised using an X-ray diffractometer (XRD), a scanning electron microscope (SEM) and Fourier transform infra-red (FTIR). Quantum computational studies were conducted in order to determine parameters such as the energy of the highest occupied molecular orbital (EHOMO) and the energy of the lowest occupied molecular orbital (ELUMO). The Gaussian 09 program density functional theory at the 6-311++(d,p) basis set was used to investigate the interaction between the organic and inorganic molecules, therefore examining both interaction energies. The XRD results confirmed that a large amount of hydroxyapatite was present in the extract, with a high diffractive peak at 32θ and small amounts of collagen picked up between 13θ and 25θ. SEM results showed the percentage weight of atoms, such as carbon (19.8%), calcium (27%), oxygen (41.3%) and phosphate (11.9%), which were found to be present in both the organic and inorganic part of the FS sample. FTIR results confirmed the presence of hydroxyl (3200–3500 cm⁻¹), carbonate (1620–1700 cm⁻¹) and phosphate groups (1200–800 cm⁻¹). The computation studies showed that hydroxyapatite was the most reactive molecule, as it had the highest EHOMO of −0.2076 eV compared with that of collagen at −0.2470 eV. The interaction energy of the FS molecule was −615 kJ/mol. Full article

Family Parvoviridae consists of small, non-enveloped viruses with linear, single-stranded DNA genomes of approximately 4-6 kilobases, subdivided into three subfamilies, Parvovirinae, Densovirinae, and Hamaparvovirinae, and unassigned genus Metalloincertoparvovirus. Parvoviruses of aquatic animals infect crustaceans, mollusks, and finfish. This review describes these parvoviruses, which are highly host-specific and associated with mass morbidity and mortality in both farmed and wild aquatic animals. They include Cherax quadricarinatus densovirus (CqDV) in freshwater crayfish in Queensland, Australia; sea star-associated densovirus (SSaDV) in sunflower sea star on the Northeastern Pacific Coast; Clinch densovirus 1 in freshwater mussels in the Clinch River, Virginia, and Tennessee, USA, in subfamily Densovirinae; hepatopancreatic parvovirus (HPV) and infectious hypodermal and hematopoietic necrosis virus (IHHNV) in farmed shrimp worldwide; Syngnathid ichthamaparvovirus 1 in gulf pipefish in the Gulf of Mexico and parts of South America; tilapia parvovirus (TiPV) in farmed tilapia in China, Thailand, and India, in the subfamily Hamaparvovirinae; and Penaeus monodon metallodensovirus (PmMDV) in Vietnamese P. monodon, in unassigned genus Metalloincertoparvovirus. Also included in the family Parvoviridae are novel parvoviruses detected in both diseased and healthy animals using metagenomic sequencing, such as zander parvovirus from zander in Hungary and salmon parvovirus from sockeye salmon smolts in British Columbia, Canada. Full article

As an important economic fish resource, germplasm resources and phenotypic measurements of tilapia are of great importance in the direction of culture and genetic improvement. Furthermore, accurate identification and precise localization of tilapia body parts are crucial for enabling key technologies such as automated capture and precise cutting. However, there are some problems in the semantic segmentation of tilapia fish, including the accuracy of target edge segmentation and the ambiguity in segmenting small targets. To improve the accuracy of semantic segmentation of tilapia parts in real farming environments, an improved Deeplabv3+ network model method is proposed for implementing tilapia part segmentation to facilitate phenotypic measurements on tilapia in this paper. The CBAM module is embedded in the encoder, which can improve the accurate identification and localization of tilapia parts by adaptively adjusting the channel weights and spatial weights and better focus on the key features and spatial connections of tilapia body parts. Furthermore, the decoding part of the Deeplabv3+ model is optimized by using SENet, which greatly increases the segmentation accuracy of the network by establishing the interdependence between channels while suppressing useless features. Finally, model performance is tested and compared with the original network and other methods on the tilapia part segmentation dataset. The experimental results show that the segmentation performance of the improved network is better than other networks, such as PSPNet and U-Net, and the IoU values in the head, fins, trunk, and tail of the fish body are 9.78, 2.27, 6.27, and 6.58 percentage points higher than those of the Deeplabv3+ network, respectively. The results validate the effectiveness of our approach in solving the above problems encountered in the semantic segmentation of tilapia parts. Full article

In this study, umami-rich seasoning powder was produced from the offcuts of Taiwanese tilapia (Oreochromis mossambicus) by cooking concentration and spray drying of granules while yielding an abundance of glutamic acid (0.23 mg/100 g), glycine (0.10 mg/100 g), aspartic acid (0.11 mg/100 g), lysine (0.10 mg/100 g), and 11 other aminic acids. It exhibited water content (3.81%), water activity (0.3), powder yields (68.83%), and a good water solubility index (99.89%), while the particle microstructure was a spherical powder. Additionally, it received the highest overall preference score (7.53) in the consumer-type sensory evaluation compared to commercially available seasonings. This study proves that offcuts may be part of the human diet after proper processing and can be widely used to flavor savory food. The producers involved could increase their economic returns while meeting the environmental challenges. The practical contribution could create incremental value for products to critical stakeholders at each point in the tilapia supply chain with an operational guide for transitioning from inefficient to innovative circular practices. Full article

Concentrations of heavy metals (HMs) were assessed in Tilapia spp. from selected communities in Calapan City, Philippines. Eleven (11) inland farmed tilapia samples were collected and analyzed for HMs concentration using X-ray fluorescence (XRF). The 11 fish samples were cut into seven pieces, according to the fish body parts, constituting a total of 77 samples. These fish samples were then labeled as bone, fins, head, meat, skin, and viscera. Results showed that the mean concentration of Cd in all parts of tilapia exceeded the Food and Agriculture Organization/World Health Organization (FAO/WHO) limits. The highest concentration was recorded in the fins, which was sevenfold higher than the limit. The trend of the mean concentration of Cd in different parts of tilapia was fins > viscera > skin > tail > head > meat > bone. The target hazard quotient (THQ) recorded a value less than 1. This means that the population exposed to tilapia, within the area where fish samples originated, were not at risk to non-carcinogens. The concentrations of Cu, Pb, Mn, Hg, and Zn in different parts, particularly in skin, fins, and viscera, also exceeded the FAO/WHO limits. The calculated cancer risk (CR) in consuming the fish skin, meat, fins, bone, viscera, and head was higher than the USEPA limit. This indicated a possible carcinogenic risk when consumed regularly. Most of the correlations observed between HMs in various parts of the tilapia had positive (direct) relationships, which were attributed to the HM toxicity target organ characteristics. Results of the principal component analysis (PCA) showed that most of the dominating HMs recorded in tilapia were attributable to anthropogenic activities and natural weathering within the watershed of agricultural areas. The agriculture area comprises about 86.83% of the overall land area of Calapan City. The identified carcinogenic risks were associated with Cd. Therefore, regular monitoring of HMs in inland fishes, their habitat, and surface water quality shall be carried out. This information is useful in creating strategies in metals concentration monitoring, health risks reduction program, and relevant guidelines that would reduce the accumulation of HM in fish. Full article

Tilapia farming is the predominant aquaculture activity, with 4623 aquaculture farms in Mexico alone. It is relevant to apply technological alternatives to mitigate production costs, mainly those associated with supporting energy savings for aeration and water pumping in aquaculture farms. There is limited information confirming the feasibility of implementing photovoltaic systems connected to the grid (On grid-PV) in aquaculture farms. The working hypothesis proposed for the development of the work was that On Grid PV systems in Tilapia aquaculture farms in Mexico are technically feasible, economically viable and environmentally acceptable. Therefore, the objective of this research is to design a grid-connected photovoltaic system for rural Tilapia aquaculture farms in Mexico and analyze it with a feasibility assessment through technical, economic and environmental variables, as part of the link between academia and the productive sector. Methodologically, the On Grid-PV design was carried out in an aquaculture farm in Veracruz, Mexico, as a case study. It was developed in two stages: the field phase (1), where a non-participant observation guide and a survey with open questions were applied to perform the energy diagnosis, and the cabinet phase (2) where the calculation of the economic and environmental variables was carried out with the clean energy management software Retscreen expert, the engineering design was based on the Mexican Official Standard for electrical installations, and Sunny Design 5.22.5 was used to calculate and analyze the electrical parameters of the On Grid PV. The results revealed an investment cost of USD 30,062.61, the cost per KWp was of 1.36 USD/Watt, and the economic indicators were the net present value (USD 41,517.44), internal rate of return (38.2%) and cost–benefit ratio (5.6). Thus, the capital investment is recovered in 4.7 years thanks to the savings obtained by generating 2429 kW/h per month. As for the environment, it is estimated that 11,221 kg of CO2 equivalent would be released into the atmosphere without the On Grid-PV. In conclusion, the hypothesis is accepted and it is confirmed that On Grid-PV installations for Tilapia farms are technically feasible, economically viable and environmentally acceptable; their implementation would imply the possibility for aquaculture farms to produce Tilapia at a lower production cost and minimized environmental impact in terms of energy. It is recommended that aquaculture farmers in Mexico and the world implement this eco-technology that supports the sustainable development of aquaculture. Full article

The aim of the present study was to evaluate the effects of a Jerusalem artichoke-supplemented diet on the blood chemistry, growth performance, intestinal morphology, expression of antioxidant-related genes, and disease resistance against Aeromonas veronii challenge in juvenile red tilapia. A completely randomized design (CRD) was followed to feed red tilapias with three experimental diets: control, 5.0 g/kg JA-supplemented (JA5), or 10.0 g/kg JA-supplemented (JA10) diets in triplicates for 4 weeks. The results revealed that the growth performance, weight gain (WG), specific growth rate (SGR), and average daily gain (ADG) of fish fed diets JA5 and JA10 were significantly higher (p < 0.05) than those of fish fed the control diet. Fish fed the control diet had significantly higher T-bilirubin, D-bilirubin, and ALT in blood serum than fish fed JA5 and JA10, as well as higher BUN than fish fed JA5. The number of goblet cells in the proximal and distal parts of the intestine revealed that the number of acid, neutral, and double-staining mucous cells of fish fed diets JA5 and JA10 was significantly higher (p < 0.05) than in fish fed the control diet. The diets including the prebiotic (JA5 and JA10) were associated with a significant increase in the expression of gpx1 and gst antioxidant-related genes and disease resistance against A. veronii in juvenile red tilapia. Therefore, JA5 and JA10 can be employed as promising prebiotics for sustainable red tilapia farming. Full article

To consider diet optimization for the growth and health of fish under intensive aquaculture systems, with a focus on the farming of Nile tilapia and red tilapia in Thailand, we conducted an experiment based on a completely randomized design (CRD), with three treatments and four replicates. Three diets, supplemented with different trace minerals, were applied to selected groups of fish: (a) a control diet, without organic trace minerals supplementation; (b) a T1 diet of chromium-L-methionine at 500 ppb, in combination with a zinc amino acid complex at 60 parts per million (ppm); and (c) a T2 diet of chromium-L-methionine at 500 ppb in combination with selenomethionine at 300 ppb. Red tilapia with an initial mean weight of 190 ± 12 g/fish were randomly distributed into cages of 2 × 2 × 2.5 m in a freshwater pond (12 cages in total), with 34 fish per cage and a density of 17 fish/m³. During the 8 week feeding trial, the fish were fed 3–4% of their body weight twice a day. The fish were weighed, then blood samples were collected to study their immune responses. The intestines were collected, measured, and analyzed at the end of the feeding trial. The results showed that the red tilapia that were fed with diets of chromium-L-methionine in combination with a zinc amino acid complex in the T1 treatment had significantly (p < 0.05) higher final weights, weight gains, average daily gains (ADGs), and better feed conversion ratios (FCRs), compared with fish that were fed with the control diet without organic trace minerals and with fish that were fed with the T2 diet (p < 0.05). The midgut and hindgut villus heights of the group fed with chromium-L-methionine in combination with a zinc amino acid complex in the T1 treatment were significantly higher than those of the other groups (p < 0.05). The levels of the antioxidative enzyme superoxide dismutase (SOD) and lysozyme activity were not significantly different from those of fish that were fed with the control diet (p > 0.05), whereas the glutathione level tended to increase (p < 0.1) in fish that were fed with chromium-L-methionine in combination with selenomethionine in the T2 treatment. Therefore, we concluded that chromium-L-methionine in combination with a zinc amino acid complex or selenomethionine clearly enhanced red tilapia’s growth performance and feed utilization through the promotion of antioxidative enzyme activity and immune response. Full article

The lower Meghna River, the easternmost part of the Ganges Delta, faces severe anthropogenic perturbations as it receives a huge discharge and industrial effluents. To measure the metal concentrations and human health hazards, edible tissues of 15 commercially important fish species were collected from the local fish markets and the lower Meghna River, Bangladesh. Trace and heavy metals such as Pb, Cr, Cu, Zn, Mn, Fe, Hg, Ni, Ca, Co, Se, Rb, Sr, and As were detected using the Energy Dispersive X-ray Fluorescence (EDXRF) method. The hierarchy of mean metal concentrations obtained was: Fe (162.198 mg/kg) > Zn (113.326 mg/kg) > Ca (87.828 mg/kg) > Sr (75.139 mg/kg) > Cu (36.438 mg/kg) > Se (9.087 mg/kg) > Cr (7.336 mg/kg) > Mn (6.637 mg/kg) > Co (3.474 mg/kg) > Rb (1.912 mg/kg) > Hg (1.657 mg/kg) > Ni (1.467 mg/kg) > Pb (0.521 mg/kg) > As (BDL). Based on the metal concentration obtained, the carnivorous species contained more metals than omnivores and herbivores. Similarly, the euryhaline and benthic feeder fishes had more metals than the stenohalines and demersal fishes. The metal pollution index (MPI) suggested that the highly consumed fish species Tilapia (Oreochromis mossambicus) and Rui (Labeo rohita) accumulated higher metals than other fishes. Both the Targeted Hazard Quotient (THQ) and Hazard Index (HI) values for adult and child consumers were <1, indicating that consumers would not experience the non-carcinogenic health effects. Although children were more susceptible than adults, carcinogenic risk (CR) exposure of Cr for all the consumers was found in the acceptable range (10⁻⁶ to 10⁻⁴), but the CR exposure of Pb was negligible for all the consumers. The correlation, principal component analysis (PCA), and cluster analysis were conducted to identify the sources of metals identified from the fish tissue. The results indicated that the probable sources of the pollutants were anthropogenic, arising from agricultural activities, electroplating materials, and lubricants used near the study area. However, the present study showed a different metal concentration in the samples at different levels but within the threshold levels non-carcinogenic and carcinogenic health risks; hence, the fishes of the area, in general, are safe for human consumption. Full article

This study aimed to investigate the natural feeding behavior of Nile tilapia in Lake Langeno, Ethiopia, with emphasis on potential spatial, size and seasonal effects on ingested food items. This study of the food and feeding biology of O. niloticus in Lake Langeno, Ethiopia, was conducted from March 2016to February 2017. Fish samples were collected monthly from six different sampling sites using different mesh sizes of gillnets. A total of 610 fish specimens with full stomachs were considered for the assessment of feeding biology. In total, seven food items, namely phytoplankton, zooplankton, insects, detritus, macrophytes, fish parts and nematodes, were identified from the fish stomach contents. Phytoplankton was the most commonly consumed food prey, followed by detritus, zooplankton and macrophytes. The other food items were occasionally and randomly consumed. Phytoplankton and detritus were the dominant food prey in the dry season, with zooplankton and macrophytes the main prey during the wet months. The contribution of phytoplankton, zooplankton and insects were slightly highest in small-sized groups (<10 cm), whereas detritus, macrophytes and fish parts were highest in larger-size groups (>20 cm) (p < 0.05). The present results point to a concurrence of the relative importance of dietary items at the individual level, species level and among the study sites. Phytoplankton was the primary consumed food item, which indicates the specialist feeding strategy of Nile tilapia in the lake. Generally, food items of plant origin, typically associated with less protein content than animal origin food items, dominated the stomach contents of Nile tilapia. The dietary pattern of Nile tilapia in Lake Langeno shifts with size and season, aspects that might warrant further study in view of aquaculture applications as well as climate change. Full article

This study evaluates the differences in mineral and toxic trace element concentrations of Nile tilapia (Oreochromis niloticus) tissues from three aquatic ecosystems in Ethiopia—Lake Ziway, Lake Langano, and Gilgel Gibe reservoir—with a focus on edible (fillet) and discarded (digestive tract, gills, skin, and liver) parts. A total of sixty (n = 60) Nile tilapia samples were collected, comprising twenty (n = 20) fish from each lake, and analyzed by inductively coupled plasma mass spectrometry. All elements varied markedly among tissues and between the lakes. Some differences in element concentrations were attributed to differences in nutrient load in the ecosystems and the function of the tissues. For instance, the calcium concentrations in skin and gill were distinctly higher in fish from calcium-rich Lake Langano. The d iscarded parts were richer in essential trace elements, showing an opportunity to promote their use in human nutrition to increase the intake of important minerals. However, the accumulation of elements toxic to humans, such as aluminum, should be monitored and, in particular, controlled when rearing these fish in aquaculture. Full article

Although it is well known that the biological and physical characteristics of skin mucus in fishes are strongly affected by changes in environmental conditions, the influence of photoperiod and time-dependent bacterial endotoxin stimulation is not well documented. In the present study, we determined the diel variations in the basal activities of secretory proteins with known defense functions in the skin mucus of Nile tilapia (Oreochromis niloticus) maintained under two photic environments: equal length of day and night (12L:12D, LD) or total darkness (0L:24D, DD). A second experiment was conducted to determine how time-dependent (i.e., day versus night) lipopolysaccharide (LPS) challenge could influence these skin mucosal defenses. The results revealed that LD signal differentially modulated the activities of mucosal immune molecules. Fish subjected to LD regime showed significantly higher levels of skin mucus lysozyme and protease at nighttime than at daytime. This distinct feature was not observed in fish under DD. There was no general mucosal response patterns to time-dependent LPS challenge. Nonetheless, protease and lysozyme, which were identified to be at elevated levels at night, were significantly modulated when the endotoxin was administered at nighttime. Ceruloplasmin was the only molecule that responded to LPS challenge at daytime, where its activity significantly increased at 8 h post-stimulation. Collectively, the results revealed that photoperiod cues influenced the activities of mucosal defenses and this may play, at least in part, in the temporal sensitivity to bacterial endotoxin. Full article

Fish social behavior can be affected by artificial environments, particularly by factors that act upon species that show aggressive behavior to set social rank hierarchy. Although aggressive interactions are part of the natural behavior in fish, if constant and intense, such interactions can cause severe body injuries, increase energy expenditure, and lead the animals to suffer from social stress. The immediate consequence of these factors is a reduced welfare in social fish species. In this paper, we consider the factors that impact on the social behavior and welfare of Nile tilapia, an African cichlid fish widely used both in fish farms and in research; this species is frequently used as a model for physiology and behavior research. This is a polygynous species whose males interact aggressively, establishing a territorial based hierarchy, where a dominant male and several subordinate males arise. When social stability is shrunk, the negative effects of prolonged fighting emerge. In this paper, we summarized how some of the common practices in aquaculture, such as classifying individuals by matching their sizes, water renewal, stock density, and environment lighting affect Nile tilapia social aggressive interactions and, in turn, impact on its welfare. We also discuss some ways to decrease the effects of aggressive interactions in Nile tilapia, such as environment color and body tactile stimulation. Full article

Osteosarcoma (OS) is a common malignant bone cancer. The relatively high density of a person’s bone structure means low permeability for drugs, and so finding drugs that can be more effective is important and should not be delayed. MSPs are marine antimicrobial peptides (AMP) and natural compounds extracted from Nile tilapia (Oreochromis niloticus). MSP-4 is a part of the AMPs series, with the advantage of having a molecular weight of about 2.7-kDa and anticancer effects, although the responsible anticancer mechanism is not very clear. The goal of this study is to determine the workings of the mechanism associated with apoptosis resulting from MSP-4 in osteosarcoma MG63 cells. The study showed that MSP-4 significantly induced apoptosis in MG63 cells, with Western blot indicating that MSP-4 induced this apoptosis through an intrinsic pathway and an extrinsic pathway. Thus, a pretreatment system with a particular inhibitor of Z-IETD-FMK (caspase-8 inhibitor) and Z-LEHD-FMK (caspase-9 inhibitor) significantly attenuated the cleavage of caspase-3 and prevented apoptosis. These observations indicate that low concentrations of MSP-4 can help induce the apoptosis of MG63 through a Fas/FasL- and mitochondria-mediated pathway and suggest a potentially innovative alternative to the treatment of human osteosarcoma. Full article

Streptococcus agalactiae is an emerging infectious disease adversely affecting Nile tilapia (Niloticus oreochromis) production in aquaculture. Research carried out in the last decade has focused on developing protective vaccines using different strategies, although no review has been carried out to evaluate the efficacy of these strategies. The purpose of this review is to provide a synopsis of vaccination strategies and antigen delivery systems currently used for S. agalactiae vaccines in tilapia. Furthermore, as shown herein, current vaccine designs include the use of replicative antigen delivery systems, such as attenuated virulent strains, heterologous vectors and DNA vaccines, while non-replicative vaccines include the inactivated whole cell (IWC) and subunit vaccines encoding different S. agalactiae immunogenic proteins. Intraperitoneal vaccination is the most widely used immunization strategy, although immersion, spray and oral vaccines have also been tried with variable success. Vaccine efficacy is mostly evaluated by use of the intraperitoneal challenge model aimed at evaluating the relative percent survival (RPS) of vaccinated fish. The major limitation with this approach is that it lacks the ability to elucidate the mechanism of vaccine protection at portals of bacterial entry in mucosal organs and prevention of pathology in target organs. Despite this, indications are that the correlates of vaccine protection can be established based on antibody responses and antigen dose, although these parameters require optimization before they can become an integral part of routine vaccine production. Nevertheless, this review shows that different approaches can be used to produce protective vaccines against S. agalactiae in tilapia although there is a need to optimize the measures of vaccine efficacy. Full article