Freshwater Tilapia Research Articles

Environmental and human health risk of potentially toxic metals in freshwater and brackish water Nile tilapia (Oreochromis niloticus) aquaculture.

Tilapia aquaculture is rapidly expanding worldwide, particularly in Bangladesh. However, metal pollution in aquaculture presents significant environmental and human health risks. This study aimed to evaluate the concentrations of 13 potentially toxic metals (As, Be, Cd, Co, Cr, Cu, Hg, Ni, Pb, V, Mn, Se, and Zn) in Nile tilapia (Oreochromis niloticus), surface water, and sediment from freshwater and brackish water aquaculture ponds. The study also assessed the associated environmental and human health risks. Samples of tilapia, water, and sediment were collected between October and November 2021 and analyzed using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The estimated daily intake (EDI) of As, Cr, Pb, Se, and Zn in tilapia muscle of both freshwater and brackish water, as well as Cd and Ni in brackish water, exceeded recommended EDI values. The Target Hazard Quotient (THQ) was less than 1 for most metals, except for As in brackish water tilapia and Cr in both freshwater and brackish water tilapia, indicating potential health risks. The Target Cancer Risk (TR) values for As in both freshwater and brackish water tilapia, and for Cr and Ni in freshwater tilapia, exceeded acceptable ranges. While the concentrations of metals in surface water of both freshwater and brackish water tilapia farms varied, all mean concentrations were below WHO recommended limits. The contamination factor (Cf) values were less than 1 for all metals in both types of aquaculture ponds, except for Zn in freshwater sediment and Se in brackish water sediment. Additionally, the calculated risk indices including the Pollution Load Index (PLI), Geoaccumulation Index (Igeo), Ecological Risk Factor (Er), and Potential Ecological Risk Factor (PER) for sediment were below the risk thresholds values (PLI < 1, Igeo < 0, Er < 40, and PER < 150). The significant positive correlations were found between tilapia muscle and the sediment of the respective ponds for arsenic (As) (ρ= 0.8, p<0.002) and Cr (ρ= 0.7, p<0.02). Although the levels of studied metals in water and sediment from freshwater and brackish water aquaculture ponds were generally within recommended guidelines, this study underscores the need for continuous monitoring and preventative measures, particularly to address elevated levels of As and Cr in tilapia muscle, which may pose potential risks to human health.

Impact of Temperature on the Growth Performance, Survival Rate, Osmoregulation, Dissolved Oxygen and Physiological Changes of Freshwater Tilapia (Oreochromis mossambicus)

For many aquatic species, any changes in water temperature affect their survival. This study was performed to investigate the effect of rising temperature on the growth parameters, protein content, dissolved oxygen content, moisture content osmoregulation, and physiological activity of freshwater Tilapia (Oreochromis mossambicus). The experiments were set in plastic fish tanks, the experimental tank placed in direct sunlight and the control tank in shade, and measuring temperature and pH daily, with proper aeration and feed was provided. The study found that increasing water temperature led to higher mortality rates and low survivability percentages in fish, with a higher growth rate in the experimental group with a pH range of 5.7 to 8.2. High dissolved oxygen levels were recorded during the experimental period, with a mean difference of 26.56 compared to the control group, possibly causing restless movement in fish. The study revealed that the alkalinity of water decreases with increasing temperature. The study found that increased salinity led to a significant increase in growth performance, indicating an increase in metabolic rate, and a decrease in alkaline nature. The difference between the mean protein value in the experimental and control groups is 0.896mg/ml. Thermal limitations may negatively impact O. mossambicus physiological responses, impacting aquaculture production due to predicted global climate change-induced water temperature changes.

Gill morphometrics of freshwater Tilapia zillii as an indicator of fish welfare

Tilapia zillii was used to examine the effect of environment on gill morphometric therefore to discover the probability of using gill morphometrics to measure welfare in wild fish. Thirty mature Tilapia zillii was collected from Lagoon of Ain-Ziyana in eastern of Benghazi city and the sizes of their gills were estimated. The gill respiratory surface area of Tilapia zillii reached from 851.31 mm² to 1929.32 mm² ̸ g of body weight. The connection among gill respiratory surface area and fish body weight was found to be highly significant (P= 0.001). The gill respiratory surface area of Tilapia zillii rise as the fish grows this may be since the gill filaments number, the secondary lamellae number and the surface area of secondary lamellae increases. Great gill surface area might support survival of Tilapia fish in oxygen-stressed. This recommends that the measure developed here could be possibly used as an guide of welfare in wild fish.

Cytogenetic study of pathogenomics of Aspergillus niger on the freshwater host fish Oriochromis niloticus

Infected fresh water Tilapia Oreochromis niloticus, were brought alive from Canning fisheries and aquatic resource, Canning, India to parasitology laboratory, Department of Zoology for pathogenic examination. Macroscopic production of infection observed and the specimen was isolated and characterized on the basis of morphological and molecular analysis. The species was identified as Aspergillus niger. The effect of this pathogenic fungus on host physiology was observed by monitoring changes in biochemical, histological parameters. Native polyacrylamide gel electrophoresis have been used to analyze malate dehydrogenase (MDH), acid phosphatase (Acph) and peroxidase (Px) isoenzymes in different tissues (liver, kidney, muscle and heart) of the host fish in order to study the tissue specificity of these isoenzymes. The percentage amount of MDH in general varied significantly between muscle and different studied tissues. Peroxidase isoenzyme was recorded in liver and heart only with significant increase in liver. The cumulative mortalities of the intraperitoneal infection increased along with the sporangiospore concentrations; the highest mortality observed was 70% with108 CFU as compared to the control. Bangladesh J. Zool. 51(1): 99-117, 2023

Thiamphenicol and florfenicol combination in Nile tilapia: Simultaneous detection and quantification in plasma and muscle plus skin samples, and pharmacokinetics following single oral administration

Thiamphenicol (TAP) and florfenicol (FFC) combination has in vitro and in vivo synergistic activity against fish bacterial pathogens. However, a lack of information on its pharmacokinetics (PK) and pharmacodynamics (PD) in fish limits its further application. Therefore, this study aimed to develop and validate analytical methods for simultaneous detection and quantification of TAP and FFC in tilapia plasma and muscle plus skin samples and to determine the PK in freshwater tilapia at 30 ± 0.32 °C after a single oral dose of 5 mg kg−1 TAP +3.75 mg kg−1 FFC. Antimicrobial concentrations were analyzed by HPLC-MS. The PK characteristics were estimated by a non-compartmental model (linear up/log down). Precise, and sensitive methods were developed using ethyl acetate (plasma) and a modified QuEChERS (muscle plus skin) for extraction. Both methods were successfully applied to analyze the plasma and muscle plus skin samples in the PK study. The highest concentrations of TAP and FFC were detected at 0.5 h (6.34 and 3.34 μg mL−1) and 16 h (8.20 and 11.37 μg mL−1) post-administration in plasma and muscle, respectively. There was no significant difference between the peak concentration and apparent volume of distribution during the terminal phase of each antimicrobial in different tissues. However, the peak time, the area under the concentration-time curve, and mean residence time were higher in the muscle, for both antimicrobials (P < 0.05). The calculated PK parameters and the curve obtained for both antimicrobials emphasize their fast absorption and distribution even when used in combination. The results from this study could help establish antimicrobial susceptibility testing interpretative categories and design rational dosing regimens for TAP and FFC combination.

Determination of Multi-Class Antibiotics Residues in Farmed Fish and Shrimp from Sri Lanka by Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry (UPLC-MS/MS)

Antibiotics have been used to control the aquatic environment in both therapeutic and prophylactic ways. Antibiotics are particularly difficult to extract due to their strong interactions with biological matrices. In this study, UPLC-MS/MS method was developed and validated for quantitative confirmatory analysis of multi-class antibiotics residues in fish and shrimp. Fourteen antibiotics belonging to sulphonamides, β-lactams, quinolones, sulfones and macrolides were determined within one chromatographic run. The samples were suspended in 0.1 M HCl, and the analytes were extracted into ethyl acetate. The extracts were defatted with cyclohexane. The limits of quantification (LOQ) ranged from 0.24 to 1.32 µg kg−1 for fish and 0.42–1.62 µg kg−1 for shrimp samples. The recoveries ranged from 75 to 105%. The method was applied to the analysis of farmed freshwater Tilapia fish (Oreochromis niloticus) and shrimp (Penaeus monodon) collected in Sri Lanka. Sulfacetamide (4.31 ± 0.70 µg kg−1) and sulfamethoxypyridazine (0.75 ± 0.15 µg kg−1) were detected in the fish, and sulfapyridine (0.21–0.56 µg kg−1) and sulfadoxine (0.35–1.44 µg kg−1) were detected in the shrimp samples. The concentrations complied with the EU regulation limits for veterinary drug residues in seafood and did not pose a risk in terms of food safety.

Effect of Chemical Corexit 9527 on28 Day old TILAPIA GUINEENSIS FINGERLINGS

The primary focus of this study is to assess the toxicity of the chemical corexit 9527 to 28 day old fresh water tilapia guineensis fingerlings. The toxicity of the chemical corexit 9527 to 28 day old fresh water tilapia guineensis fingerlings was studied in the static renewal bioassay glass tank, using tap water. The 28 day old tilapia guineensis fingerlings collected from Ikpoba HillRiver, Edo State was used to access lethal concentrations of dispersant corexit 9527. Differential sensitivity of test organisms to corexit 9527 was observed.This was achieved by predictive application. The LC50 is actually used as an estimate of the incipient lethal level which is also called the lethal threshold concentration, asymptotic LC50 or tolerant limit. The incipient lethal level is the concentration at which half the population will die in an indefinite period of time. It is estimated by the LC50 at that timefor which no further toxicity has been observed. This steady state LC50 is theincipient lethal level. In fish tests, this often occurs within 4 days, and this is one rationale behind the 96-hour length for a standard acute fish test.The median lethal concentration LC50 of dispersant corexit 9527 on tilapia guineensis was determinedusing a computerized probit analysis according to the methods of finney. The median lethal concentration, LC50 for the 28 day old tilapia guineensis were 409.71mg/l and 367.20mg/lfor 3 and 4 days respectively.The 28 day old tilapia guineensis showed a high level tolerance to lower concentrations of corexit 9527 and high level toxicity at the highest concentration which recorded 100% mortality even at 24-hour exposure period.

Evaluation of methyl orange adsorption potential of green synthesized chitosan-silver nanocomposite (CS–AgNC) and its notable biocompatibility on freshwater Tilapia (Oreochromis nitoticus)

Nanomaterials mainly nanocomposites possess unique physical and chemical properties which makes them superior and indispensable. Though much research has been focused on the properties and application of nanocomposites, the eco-toxicity assessment is one among top priority, which aims to protect the population of concerned biological component and their ecosystem. With this objective, the present study has undertaken an initiation to evaluate the efficacy of chitosan-silver nanocomposite for methyl orange adsorption property (CS–AgNC) and also assessed the toxicity impact on growth parameters of freshwater Tilapia. Batch in vitro studies showed that all the tested dosages of the nanocomposite were effectively adsorbing maximum concentration of methyl orange. The synthesized nanocomposite was administrated to the tested fishes followed by the determination of various growth, nutritional parameters, gene expression of enzymatic antioxidants and liver, and intestinal tissues histology. Obtained results indicated that nanocomposite treatment was not projected as a toxic impact on all the tested growth, and nutritional parameters. Histology study showed that the exposure of Tilapia to nanocomposite has not shown any detrimental effect on antioxidants gene expression and liver, intestinal tissue architecture. Hence, all these findings indicated that chitosan-silver nanocomposite prepared in our present system was found to be biocompatible which suggested the possible utilization and release of the nanocomposite into the divergent ecosystem without affecting non-target organisms (NTO).

Usage pattern of chemicals, biologicals and veterinary medicinal products in Indian aquaculture

AbstractThe use of chemicals, biologicals and veterinary medicinal products (VMPs) helps in healthy and sustainable fish production. Information on the use of these products is essential for assessing farming practices, potential human health and environmental risks. A questionnaire‐based nationwide survey covering aquaculture farms (n = 2936) producing carps, tilapia, pangasius and rainbow trout in freshwater and shrimp in brackishwater estimated the use of 52 different types of inputs which included disinfectants (597 g t−1), probiotics (2.28 kg t−1), environmental modifiers (22.82 kg t−1), nutritional supplements (1.96 kg t−1), natural anti‐infective agents (293 g t−1), herbicide and piscicides (844 g t−1), antibiotics (2 mg PCU−1), antifungal (4 mg PCU−1), and antiparasitic (14 mg PCU−1) agents. The bulk of these inputs was used for soil and water quality improvement and had low environmental and human safety concerns. The multivariate analysis revealed significant variation in the frequency and quantity of compounds use among farm groups. Redundancy analysis revealed a significant association between the number of products used and stocking density. The survey also showed a considerable influence of education and farming experience on the usage pattern of aquaculture inputs. Results of the study indicated greater reliance of farmers on the use of disinfectants for biosecurity, nutritional supplements for enhanced growth and environmental modifiers for maintaining soil and water quality in culture systems. Though there was no use of restricted antibiotics and antiparasitic agents, the development and implementation of standard regulatory guidelines are essential for safe and effective use of inputs for sustainable aquaculture.

Parasites of Moroccan desert Coptodon guineensis (Pisces, Cichlidae): transition and resilience in a simplified hypersaline ecosystem

Sebkha Imlili (Atlantic Sahara) is a salt flat with over 160 permanent holes of hypersaline water generated in the Holocene and inhabited by euryhaline organisms that are considered to be relics of the past, including the cichlid fish Coptodon guineensis. We surveyed the fish parasites four times over one year, to i) identify the parasites, and ii) determine possible seasonality in infection patterns. Over 60% of the fish were infected by one to three helminths: an acanthocephalan in the intestine and two digenean metacercariae in the kidney, spleen, liver, muscle, and mesenteries. The acanthocephalan Acanthogyrus (Acanthosentis) cf. tilapiae was identified morphologically and molecularly; only one digenean (the heterophyid Pygidiopsis genata) could be identified molecularly. Both identified parasites were present throughout the sampling periods; the unidentified metacercariae were present only in summer and fall. Mean intensities, but not prevalence of infection by the acanthocephalan, reflected a biannual pattern of transmission. Infection accrued with fish size, possibly due to cannibalism. Because the water holes include only a few invertebrates, the intermediate hosts of these parasites can be inferred to be the gastropod Ecrobia ventrosa for the digeneans and either the copepod Cletocamtpus retrogressus or the ostracod Cyprideis torosa for the acanthocephalan. This ecosystem appears stable and provides a window into the past, as the acanthocephalan likely switched from freshwater tilapia to C. guineensis when the Sebkha formed. However, this is a vulnerable environment where the survival of these parasites depends on interactions maintained among only very few hosts.

Evaluation of Selected Chemicals used for Oil and Gas Production and Their Toxic Effects on the Niger Delta Fresh Water Tilapia Guineensis

There are projections of continuous increase in the world’s energy demand, which might result to increase in oil and gas exploration and production activities. Nigeria for instance, runs a mono-economy that largely depends on the revenues from her rich oil and gas deposits. Oil and gas exploration and production activities are expected to increase over the years in Nigeria to meet her economic needs, as well as the global energy need. However, oil and gas production activities are associated with environmental concerns, especially with respect to management of the kind of wastes it generates. A major waste generated during oil and gas completion and production operations is the Produced Water (composed of water, different production chemicals and other constituents). This study is focused on evaluation of the toxic effects of selected production chemicals on the Niger Delta freshwater Tilapia guineensis. Among the chemicals evaluated include: SPECTRUS NX1173 (Biocide), FLOGARD MS 6208 (Corrosion inhibitor), ELIMINOX (Oxygen scavenger) and EC9017A (anti-foam), while Tilapia guineensis was used as the bioindicator. Whereas there are past researches on the individual chemicals and confirmation that they are toxic in nature, there are no adequate researches on the comparative toxicity effects of these chemicals, especially on the Niger Delta environment. Produced water samples were simulated in the laboratory using the production chemicals (at different concentrations) and 2000ml of freshwater sample for each experimental setup. The fishes were acclimatized for ten days using same freshwater sample, those that survived were selected for the experiment. The mortality and survival rate of the test organism was monitored at a constant interval of one (1) hour for Ninety-six (96) hours and the percentage mortality of the test organism recorded for all the chemicals at different concentrations ranged from 100% to 10%. The lethal concentration (LC50) calculated for each of the chemicals are as follows: Corrosion inhibitor 0.002%, biocide 0.003%, oxygen scavenger 0.01% and defoamer 0.176%. The corrosion inhibitor was the most toxic as there was 100% mortality of the Tilapia guineensis within 24 hours of the test period, while the defoamer was the least toxic as there were more survival of the test organism at the end of the test period. The test results indicated that all the production chemicals used in this research were toxic, their lethal concentrations differed from one chemical to the other, and the corrosion inhibitor and biocide had the highest toxicity effect on the organisms. The research findings could be used as a basis by the Nigerian regulatory agencies for possible review of currently approved completion and production chemicals for oil and gas activities, as well as produced water disposal options, especially discharge in water bodies in the Niger Delta.

Toxicity evaluation and oxidative stress response of fumaronitrile, a persistent organic pollutant (POP) of industrial waste water on tilapia fish (Oreochromis mossambicus)

The study was designed to determine the impact of acute toxicity of fumaronitrile exposure through tissue damaging, oxidative stress enzymes and histopathological studies in gills, liver and muscle cells of freshwater tilapia fish (Oreochromis mossambicus). In gill, liver, and muscle cells, biochemical indicators such as tissue damage enzymes (Acid Phosphatase (ACP), Alkaline Phosphatase (ALP), and Lactate Dehydrogenase (LDH)) and antioxidative enzymes (Superoxide Dismutase (SOD); Catalase (CAT); Glutathione-S-transferase (GST); Reduced Glutathione (GSH); Glutamate oxaloacetate transaminase (GOT) and Glutamate pyruvate transaminase (GPT) were quantified in the time interval of 30, 60 and 90 days exposure to the fumaronitrile. After 90 days, under 6 ppb exposure conditions, the acid phosphatase (ACP) levels of fish increased significantly in the gills (3.439 μmol/mg protein/min), liver (1.743 μmol/mg protein/min), and muscles (2.158 μmol/mg protein/min). After 90 days of exposure to the same concentration and days, ALP activity increased significantly in gills (4.354 μmol/mg protein/min) and liver (1.754 μmol/mg protein/min), but muscle cells had a little decrease in ALP activity (2.158 μmol/mg protein/min). The LDH concentration in gills following treatment with fumaronitrile over a period of 0–90 days was 3.573 > 3.521 > 2.245 μmol/mg protein/min over 30 > 60 > 90 days. However, at the same dose and treatment duration, a greater LDH level of 0.499 μmol/mg protein/min was found in liver and muscle cells. Histopathological abnormalities in the gills, liver, and muscle cells of treated fish were also examined, indicating that fumaronitrile treatment generated the most severe histological changes. The current study reveals that fumaronitrile exposure has an effect on Oreochromis mossambicus survival, explaining and emphasising the risk associated with this POP exposure to ecosystems and human populations.

Risk factors related to Streptococcosis disease of tilapia in freshwater aquaculture

The risk factors related to the occurrence of Streptococcosis disease in cultured freshwater tilapia in Hai Duong, Bac Giang, An Giang, Vinh Long, and Dong Thap provinces, were determined based on results obtained by proactive monitoring approach, including observing and analysing water quality and disease occurrence in tilapia during the period 2012 to 2019. The results showed that NO2-N&gt;0.25 mg/l is the most risk related to Streptococcosis disease in tilapia with odds ratio OR=37.4, followed by temperature ≥30oC (OR=16.5), H2S&gt;0.02 mg/l (OR=10), NH3&gt;1 mg/l (OR=8.2), the density of Streptococcus spp. ≥1000 cfu/ml (OR=6.9), and the lowest was pH&gt;8.5 (OR=2.5). Chemical oxygen demand (COD)&gt;10 mg/l, NH4-N&gt;1 mg/l are positively correlated, but not risk factors related to Streptococcosis in tilapia. Dissolved oxygen (DO), Aeromonas spp., and total aerobic bacteria density in cultured water were not correlated and associated with the appearance of Streptococcosis in tilapia.

Impacts of microplastics on reproductive performance of male tilapia (Oreochromis niloticus) pre-fed on Amphora coffeaeformis.

This study examines the potential defending effects of the diatom, Amphora coffeaeformis, as a feed additive versus the deleterious effects (mainly on gonads) caused by microplastics (MPs) in Nile tilapia, Oreochromes niloticus. Groups of male tilapia were pre-fed diets with four different supplementation levels of A. coffeaeformis (0%, 2.5%, 5%, and 7.5%) for 70 days, then exposed to 10 mg/L MPs for 15 days. Thereafter, samples were taken from the four experimental groups and the control fishgroup, for evaluating blood picture, erythrocytes alterations, biochemical parameters, catalase (CAT), superoxide dismutase (SDO), and total antioxidant capacity (TAC). In addition, male reproductive performance was assessed by quantifying the follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone (T), also testicular sections and GSI% were also assessed. The results showed that the number of leucocytes were significantly (p < 0.05) higher, but the number of red blood cells (RBCs), the level of Hemoglobin (Hb), the percentage of Hematocrit (Ht), the number of platelets, and the eosinophil percentages were significantly decreased (p < 0.05)when fish exposed to MPs. Biochemical parameters (ALP, glucose, uric acid, albumin, and A/G ratio) were significantly increased after MP exposure compared with the control group. Furthermore, MPs induced a significant decline in both serum LH and T levels. Testicular, histological, degenerative changes and testis-ova were found in the MP-exposed fish. Thus, A. coffeaeformis supplementation displayed ameliorative properties that detoxified the negative effects of MPs. This study provides a better understanding of the reproductive injuries caused by MPs exposureand evidence for the use of A. coffeaeformis as a natural remedy in freshwater tilapia.

Different Levels Of Addition Of Salinity To Survival, Growth And Conversion-Efficiency Feed’s Tilapia (Oreochromis sp.)

&lt;em&gt;Tilapia is one of the consumption fish commodities that was very popular with the public. The development of tilapia aquaculture was growing rapidly, especially saline tilapia. The high potential of saline tilapia development causes the demand for fingerlings to increase. This research aimed to determine the best dose of salinity increase in the effort to adapt freshwater tilapia to saline tilapia. In addition, it also observed survival, growth and feed efficiency. The method used was experimental method with completely randomized design and data were analyzed using SPSS16 and Tukey's test. The research treatments included the levels of addition of salinity by 1 ‰/day, 2 ‰/day, 3/day and 4 ‰/day. The difference in salinity had a significant effect on Survival Rate (SR), Growth Rate (GR), Specific Growth Rate (SGR), Feed Conversion Ratio (FCR) and Feed Utilization Efficiency (FUE). The best treatment in this research was the addition of salinity of 1 ‰/day with SR of 96%, GR of 35.1 g / t, SGR 1.22% w / day, FCR of 1.04 and FUE of 96%.&lt;/em&gt;

LAJU PERTUMBUHAN, KELANGSUNGAN HIDUP DAN KOMPOSISI KIMIA IKAN NILA (Oreochromis niloticus) HASIL REKAYASA DARI AIR TAWAR KE AIR LAUT

Tilapia (Oreochromis niloticus) is one of the most popular fish species and has high economic value. Increased demand for this type of fish must be matched by cultivation efforts. Limited land for cultivation ponds, so it is necessary to look for alternatives, one of which is cultivation in seawater floating marine cages. This study aims to determine the manipulation process of freshwater tilapia into seawater, the rate of growth and survival, and analysis of its chemical composition. The research used was an experimental method. The results of measuring water quality including salinity increased by 3 ppt per day, temperatures ranged from 27-30 OC, DO was between 7.0-7.5 mg/L, pH between 7,2-7,6. The absolute weight and length were 408.5 g and 26 cm, respectively, the growth rate was 2.27%, and the survival rate was 85-90%. The chemical composition values ​​include moisture content of 71.59%, ash 1.54%, fat 4.74%, 21.3% protein, and 0.83% carbohydrates. The results showed that freshwater tilapia can be manipulated to live in seawater and have a good growth and survival rate and have a high chemical composition, especially protein and fat.

Differential expression of two ATPases revealed by lipid raft isolation from gills of euryhaline teleosts with different salinity preferences.

In euryhaline teleosts, Na+, K+-ATPase (NKA) and V-type H+-ATPase A (VHA A) are important ion-transporters located in cell membrane. Lipid rafts (LR) are plasma membrane microdomains enriched in cholesterol, sphingolipids, and proteins (e.g., flotillin). Flotillin is a LR-associated protein, commonly used as the LR marker. Previous mammalian studies showed that LR may play a crucial role in ion exchanges. Meanwhile, studies on mammals and rainbow trout showed that NKA were found to be present mainly in LR. However, little is known about LR in fish. Therefore, the present study aimed to investigate the involvement of branchial LR in osmoregulation of tilapia and milkfish, two euryhaline teleosts with different salinity preferences, by (i) extracting LR from the gills of euryhaline teleosts; (ii) detecting the abundance of LR marker protein (flotillin-2) and ion-transporters (NKA and VHA A) in branchial LR and non-LR of fresh water- and seawater-acclimated milkfish and tilapia. The results indicated that the protein abundance of LR marker, flotillin-2, changed with environmental salinities in branchial LR of tilapia. In addition, flotillin-2 and NKA were only found in LR in both tilapia and milkfish gills, while VHA A were mainly present in non-LR. Relative protein abundance of NKA was found to be significantly higher in gills of freshwater milkfish and seawater tilapia, while VHA A was significantly higher in gills of freshwater tilapia and milkfish. This study illustrated differential distribution and salinity-dependent expression of NKA and VHA A in cell membrane of gill tissues of euryhaline teleosts with different salinity preferences.

Microplastics and metal burdens in freshwater Tilapia (Oreochromis niloticus) of a metropolitan reservoir in Central Mexico: Potential threats for human health

In the present study, microplastics (MPs) and metal concentrations were studied in the widely consumed tilapia (Oreochromis niloticus) fishes (n = 15) collected from a metropolitan reservoir of the Atoyac River basin, Mexico. Nearly 139 fibers were extracted from the gastrointestinal tracts and assessed using optical microscopy to evaluate their physical characteristics. The colour distribution of the fibers was mainly black (40%), blue (19%), red and white (14%). SEM images represented the surface morphology, while the elemental composition of the fibers was studied using EDX spectra. Polymer characterization using μFTIR aided in confirming the fibers as plastics (polyamide, polyester, and synthetic cellulose) and non-plastics (natural cellulose). Henceforth, ∼33% of the fibers, provisionally thought to be plastics, were natural fibers. The total metal concentrations were higher in the liver (259.24 mg kg−1) than the muscle (122.56 mg kg−1) due to diverse metabolic functions in the hepatic tissues. Human health risk assessment in terms of Hazard Index (HI) presented Pb and Zn values above unity in both adults and children, prompting regulatory measures. Statistical tests between MPs and fish biometry did not present any substantial correlations. The present study also affirmed that the presence of MPs and metals in fishes of a highly contaminated region is not only governed by their bioavailabilities, but also on the physiological characteristics of the individual organism.

Gene expression, antioxidation and growth were considerably promoted by feeding dietary vitamin E and alanyl‐glutamine dipeptide supplementation in juvenile tilapia in cold freshwater

Gene expression, antioxidation and growth were considerably promoted by feeding dietary vitamin E and alanyl‐glutamine dipeptide supplementation in juvenile tilapia in cold freshwater

Fish Scale Collagen Functionalized Thermo-Responsive Nanofibres

Smart thermosensitive polymer such as poly (N-isopropyl acrylamide) (PNIPAM) and dominant fibrous protein of connective tissue such as collagen (CLG) possess great potential in biomedical and tissue engineering applications. The objectives of current work aim to explore potential of PNIPAM and collagen by (i) establish a stable procedure to extract collagen from fresh water Tilapia fish scale (TFS) and (ii) fabricate PNIPAM and hybrid PNIPAM-CLG nanofibrous scaffolds through electrospinning technique and investigate their material-process-structure behaviour. Type I collagen was derived through acid hydrolysis of TFS. Electrospinning of PNIPAM was carried out with 16, 18 and 20 wt% PNIPAM concentration in methanol (MeOH) while PNIPAM-CLG was prepared through blending measured quantity of PNIPAM dissolved in water with collagen dissolved in acetic acid. Material properties, viscosity, morphology and thermo-physical behaviors of the derived collagen, electrospun PNIPAM and PNIPAM-CLG scaffolds were characterized. Results from SDS-PAGE and FTIR confirmed that the isolated TFS collagen is of type I. EDX revealed that demineralization eliminated the aluminium, magnesium, silicon and phosphorus while significantly reduced the sulfur elements from raw TFS. SEM observation of the collagen morphology shown a fluffy and fibrillary lamellae structure. Electrospun scaffolds were successfully fabricated with 16 and 18 wt% PNIPAM in MeOH. Both homogeneity and average fibre diameter (Davg) were greater in the 18 wt% PNIPAM scaffold, in which the Davg for 16 and 18 wt% were ~110 and ~131.7 nm respectively. However, PNIPAM at 20 wt% failed to be electrospun owing to its excessively high viscosity. On the other hand, SEM observation revealed that the electrospun hybrid PNIPAM-CLG scaffold has Davg of ~105.5 nm amid the presence of numerous elongated beads.