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In this study, veratrylidenehydrazide was isolated from Wedelia biflora, and compounds (1a, 2a, and 3a–j) were synthesised to evaluate their larvicidal and antifeedant activities. Veratrylidenehydrazide 1a was verified using GC‐MS. The veratrylidenehydrazide analogues 2a and 3a–j were synthesised via a condensation method with yield range 71%–92%. The compounds (1a, 2a, and 3a–j) were synthesised and characterised through FT–IR, 1H NMR, 13C NMR, mass spectrometry, and elemental analysis. Veratrylidenehydrazide 1a was verified using GC‐MS analysis. Natural veratrylidenehydrazide compound 1a and the synthesised veratrylidenehydrazide analogues (2a, 3a–j) were screened for larvicidal activity against Culex quinquefasciatus. The larvicidal activity of compound 3g was found to be highly active, while low toxicity was observed against Oreochromis mossambicus nontarget aquatic species compared to natural veratrylidenehydrazide. Compound 3g exhibited a higher binding affinity (−8.8 kcal/mol) compared to standard of temephos (−4.5 kcal/mol), equipotential binding affinity against permethrin (−9.1 kcal/mol), and diflubenzuron (−8.5 kcal/mol). Lead molecules have larvicidal properties, and their use as insecticides makes them important. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNPs) and Zinc oxide nanoparticles (ZnONPs) have been widely used and are eventually been discharged into the natural aquatic ecosystem. The current study examined and correlated the toxicity of AgNPs and ZnONPs on the Mozambique tilapia, Oreochromis mossambicus. Lethal concentration (LC50) was determined with four different concentrations (0.05, 0.10, 0.15, and 0.20 mg/L) of AgNPs and ZnONPs; subsequently, the fishes were exposed to sublethal concentrations for a period of 21 days, and the oxidative stress and antioxidant and nonantioxidant parameters were studied. Results revealed oxidative stress evinced by increased lipid peroxidation (LPO) protein carbonyl activity (PCA), glutathione‐S‐transferase (GST), glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT) activity, metallothionein (MT) activity, and reduced glutathione in chronic exposure compared with acute exposure. Nonspecific immunological characteristics such as lysozyme (LYZ), myeloperoxidase (MPO), and respiratory burst activity (RBA) were also noticed in the serum. Furthermore, severe histological damages including damages in telangiectasia and epithelial cell hyperplasia were found in the combined treated group with Ag and ZnONPs than in individual treatments. When Ag and ZnONPs were combined, a reduction in the accumulation of Ag was observed in the liver, which increased drastically in individual exposure. The current findings highlight the importance of taking into account the combined exposure and correlation of NPs, their bioavailability, and toxicity in the aquatic ecosystem. [ABSTRACT FROM AUTHOR]

This study assessed the toxicity of the Sheathmar pesticide on Oreochromis mossambicus. The 96-h median lethal concentration (LC50) was determined using probit analysis, with survivability assessed using general threshold survival models (GUTS). Over 45 days, fish exposed to sublethal Sheathmar doses were studied for changes in growth, blood profiles, and liver enzymes. According to the findings, the LC50 values of Sheathmar for Oreochromis mossambicus at different time intervals were determined as follows: 3016.64 µg/l at 24 h, 2723.13 µg/l at 48 h, 2415.45 µg/l at 72 h, and 2154.87 µg/l at 96 h. The GUTS-SD model effectively predicted fish survivability after Sheathmar exposure. Sublethal exposure led to significant alterations in growth and hematological, biochemical, and stress enzyme parameters in Oreochromis mossambicus. Moreover, the correlation matrix, integrated biomarker response (IBR), and biomarker response index (BRI) highlighted significant impacts on multiple biomarkers in Oreochromis mossambicus. Thus, the results underscore the harmful effects of Sheathmar on Oreochromis mossambicus, indicating a need for further study and mitigation. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the toxic effects of benzalkonium chloride (BAC) on Oreochromis mossambicus, a freshwater fish species. Probit analysis was used to determine the lethal concentration (LC50) of BAC for different exposure periods (24, 48, 72, and 96 h). The viability of fish exposed to BAC was assessed using the general threshold survival models (GUTS) and confirmed with relevant datasets to evaluate model accuracy. Experimental groups of fish were exposed to BAC concentrations equivalent to 10% and 20% of the 96-h LC50 for 45 days. The study revealed significant alterations in various parameters during sublethal BAC exposure. These effects included decreased specific growth rate (SGR), red blood cell count (RBC), hemoglobin (Hb) concentration, hematocrit (Ht) value, plasma protein, and albumin levels, as well as acetylcholinesterase (AChE) activities in both gills and liver. Additionally, an increase in gastrosomatic index (GSI), feed conversion ratio (FCR), plasma glucose and creatinine concentrations, alanine aminotransferase (ALT), aspartate aminotransferase (AST) enzymatic activities, catalase (CAT), superoxide dismutase (SOD), and malondialdehyde (MDA) levels were observed in the exposed fish's gills and liver. Furthermore, the study found that glutathione S-transferase (GST) and glutathione peroxidase (GPx) levels initially increased and then decreased in both gills and liver after exposure to BAC. Correlation matrix analysis, multivariate multiple regression (MMR), canonical correspondence analysis (CCA), integrated biomarker response (IBR), and biomarker response index (BRI) were utilized to assess the impact of BAC on fish, highlighting significant effects on multiple biomarkers in O. mossambicus following surfactant exposure. Thus, the study provides valuable insights into the toxic effects of BAC on this fish species, emphasizing the importance of monitoring such pollutants in aquatic environments. [ABSTRACT FROM AUTHOR]

Urbanisation and water developments in South Africa have created numerous challenges in managing water resources. Consequently, the native fish species Oreochromis mossambicus, prominent to freshwater ecosystems in South Africa now faces the threat of extinction amidst introductions of alien Oreochromis species. The species has recently been classified as Vulnerable on the IUCN Red List. Despite the economic importance of O. mossambicus within the South African region, little is known about the genetic and population dynamics of the species. In this study, we aimed to establish baseline genetic and population data, and determine the impact of water management practices on population structure. This data is crucial for the conservation and monitoring of this species across South Africa. The study revealed relatively low genetic diversity within sample localities but significant differentiation among populations. The analyses identified 16 geographically correlated genetic clusters, indicating substantial differentiation across catchments. Anthropogenic activities, changes in catchment use, and water management strategies significantly influenced the genetic population structure in the studied regions. Given the distinct genetic patterns, conservation-oriented management should prioritise maintaining existing genetic diversity to ensure the long-term survival of this vulnerable species.

Urotensin-I (UI) is a peptide belonging to the corticotropin-releasing hormone family, produced in the urophysis of teleosts. This investigation was undertaken to examine the effect of UI on the hypothalamo-hypophyseal-ovarian axis in the Mozambique tilapia, a cichlid fish. In the first experiment, administration of UI (2 μg/100 μL saline) for 22 days caused a significant reduction in the number of follicles at stages I, II, III (previtellogenic), IV (vitellogenic), and V (preovulatory), concomitant with a significant increase in the percent atresia of follicles at stages II, III, and IV than in controls. In the pituitary, gonadotropin-releasing hormone (GnRH) - positive fibres were detected in the proximal pars distalis (PPD) in both controls and UI-treated fish; however, there was a significant reduction in the intensity and percent area of GnRH-immunoreactive fibres in fish treated with UI compared with controls. The serum luteinizing hormone (LH) level was significantly lower, whereas a significant rise in the serum level of cortisol was noticed in UI-treated fish compared with controls. In the second experiment, treatment with a low dose of UI (10 mM) did not affect the number of ACTH-secreting cells in vitro, but the number of these cells was significantly higher in high-dose UI (50 mM)-treated pituitaries compared to controls. Together, the present investigation reveals for the first time that the treatment of UI affects the follicular development process through the downregulation of the GnRH-LH axis and activation of the pituitary-interrenal pathway in teleosts.

Urotensin-I (UI) is a peptide belonging to the corticotropin-releasing hormone family, produced in the urophysis of teleosts. This investigation was undertaken to examine the effect of UI on the hypothalamo-hypophysealovarian axis in the Mozambique tilapia, a cichlid fish. In the first experiment, administration of UI (2 μg/100 μL saline) for 22 days caused a significant reduction in the number of follicles at stages I, II, III (previtellogenic), IV (vitellogenic), and V (preovulatory), concomitant with a significant increase in the percent atresia of follicles at stages II, III, and IV than in controls. In the pituitary, gonadotropin-releasing hormone (GnRH) - positive fibres were detected in the proximal pars distalis (PPD) in both controls and UI-treated fish; however, there was a significant reduction in the intensity and percent area of GnRH-immunoreactive fibres in fish treated with UI compared with controls. The serum luteinizing hormone (LH) level was significantly lower, whereas a significant rise in the serum level of cortisol was noticed in UI-treated fish compared with controls. In the second experiment, treatment with a low dose of UI (10 mM) did not affect the number of ACTH-secreting cells in vitro, but the number of these cells was significantly higher in high-dose UI (50 mM)-treated pituitaries compared to controls. Together, the present investigation reveals for the first time that the treatment of UI affects the follicular development process through the downregulation of the GnRH-LH axis and activation of the pituitary-interrenal pathway in teleosts. [ABSTRACT FROM AUTHOR]

Insect-based meals have emerged as a viable global scale alternative to fish meal in aquafeed. This is mainly due to their high protein content, balanced amino acid composition, and fatty acid profile, which closely resembles that of fish meal. An 8-week trial was conducted to evaluate the growth performance, blood serum chemistry, and histomorphology of Mozambique tilapia (Oreochromis mossambicus) fed diets containing soldier termite meal as a partial substitute for fish meal. Five isonitrogenous, isolipidic, and isocaloric diets were formulated to partially replace fish meal with soldier termite meal at 0, 10, 30, 50, and 70%, labelled as D1, D2, D3, D4, and D5, respectively. The study showed that soldier termite meal could replace fish meal up to a 50% inclusion level. The growth performance and nutrient utilisation of fish fed diet D4 (50%) were comparable to fish fed the control diet. Fish fed the diet with the highest proportion of soldier termite meal (70%) showed significantly higher alanine aminotransferase and aspartate aminotransferase levels (P < 0.05). Cholesterol, triglyceride, and glucose levels were not influenced by the inclusion of soldier termite meal in the diet of Mozambique tilapia (P > 0.05). The histomorphological examination of the intestines revealed no discernible alterations. The current study has demonstrated that soldier termite meal can replace fish meal up to 50% of the feed content without inducing adverse effects on growth performance and health status of O. mossambicus. The cost-benefit analysis showed that substituting fish meal with soldier termite meal was economically sustainable. [ABSTRACT FROM AUTHOR]

The rapid development of nanotechnology needs to study the toxic effects of nanoparticles. Aluminium oxide (AL2O3 NPs) is inevitable metal oxide nanoparticles has multiple applications in various fields. The impact of AL2O3 NPs on the aquatic system is very scarce. Thus, the aim of the present study was designed to evaluate the toxic effect of AL2O3 NPs on freshwater fish Oreochromis mossambicus. The AL2O3 was synthesized by simple sol-gel method and characterized by UVspectroscopy, FT-IR, X-ray diffraction (XRD) and SEM with EDX. Further, synthesized and characterized AL2O3 nanoparticles were orally introduced to the fish Oreochromis mossambicus in sub-lethal doses of (3.3, 5, 10 mg/kg body weight) for the period of 7 days. The haematological (Hb, RBC, WBC, HCT, MCV, MCH, MCHC) indices and tissue damaging enzymes (GOT and GPT) activity were observed in gill, liver and muscle tissues of treated fishes. The results revealed that synthesized AL2O3 NPs induced significant (P< 0.05) alterations in haematology and increased (P< 0.05) GOT and GPT activity in fish at tested doses. The current study gives an insight into the toxic effect of AL2O3 NPs on freshwater fish O. mossambicus and also demonstrates that manufactured metal oxide NPs may pose potential risk to the environment and to human populations. [ABSTRACT FROM AUTHOR]

In this study, the main research institutions, literature, patents, and standards of tilapia quality safety and nutritional quality from 2017 to 2022 were statistically analyzed. It was found that in recent years, there have been many studies on tilapia in the aspects of biohazard detection, pesticide and veterinary drug residue detection, heavy metal detection, and quality changes caused by different conditions. However, research on biotoxins, risk assessment of hazard factors, analysis of functional nutrition factors, and quality evaluation and grading of tilapia remains limited. At this stage, it is recommended that efforts be made to strengthen the development of a comprehensive indicator system for tilapia quality safety and nutritional quality and to establish and enhance relevant standards to bolster the research and standard system for tilapia, thereby improving the proactive prevention and control capabilities against risks in the international market. This study clarified the current research status, development trends, and future focus areas regarding tilapia quality safety and nutritional quality, offering valuable references for researchers to grasp the research foundation and directions. [ABSTRACT FROM AUTHOR]

An 8-week feeding trial was conducted to evaluate the effect of Alates termite (Macrotermes falciger) based diet in a herbivorous (Oreochromis mossambicus) and an opportunistic predator (Clarias gariepinus). Five diets were formulated to replace fishmeal at 0, 10, 30, 50, and 70 % and were denoted D1, D2, D3, D4, and D5, respectively. Clarias gariepinus sub-adults (209.24 ± 2.41 g/fish) were stocked at 5 fish per tank in recirculating fibreglass tanks (400 L) in triplicates. Oreochromis mossambicus juveniles (7.4 ± 4.78 g/fish) were randomly stocked at 10 fish per tank in recirculating fibreglass tanks (400 L) in triplicates. Fish were fed their allocated diets, twice a day to apparent satiation. Growth performance indices (specific growth rate, thermal-unit growth coefficient) were lowest at inclusion level above 50 % in both species (P < 0.05). The nutrient utilization indices (feed intake, protein efficiency ratio) were lowest at inclusion level above 50 % in both species. The organosomatic indices (condition factor, hepato-somatic index, viscero-somatic index) were not influenced by the inclusion of Alates termite meal in both species. The aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were not influenced by Alates termite meal in O. mossambicus (P > 0.05). However, AST and ALT levels significantly increased at inclusion levels above 50 % in C. gariepinus (P < 0.05). The triglyceride, cholesterol, and glucose levels showed no significant difference across diets in both fish species (P > 0.05). The study showed that both species may utilize an insect-based diet up to 50 % inclusion levels without adverse effects on growth performance and nutrient utilization.

Although fish are often exposed to food restrictions in natural or aquafarming conditions, the relationship between altered energy status and the reproduction is not well understood. The aim of the present investigation was to elucidate the effect of chronic food-deprivation on energy status and reproductive axis in male Mozambique tilapia Oreochromis mossambicus. The controls received food ad libitum, whereas the fish in the starvation group were deprived of food for 21 days. The liver showed significantly higher levels of gluconeogenesis and triglycerides, whereas the levels of blood glucose and total protein content in the liver were significantly lower in starved fish compared to controls. Furthermore, the mean numbers of different spermatogenic cells, such as spermatogonia-A, primary spermatocytes, secondary spermatocytes, early spermatids, and late spermatids were significantly lower, but the number of spermatogonia-B did not show a significant difference compared to controls. In starved fish, there was a significant increase in germ cell apoptosis at different stages of development concomitant with faintly immunoreactive androgen receptors in the Sertoli cells of the testis compared with controls. In addition, the percent areas of gonadotropin-releasing hormone—immunoreactive fibres and luteinizing hormone—immunoreactive content—in the proximal pars distalis part of the pituitary gland were significantly lower in starved fish compared with controls. Collectively, these results suggest that decreased energy status negatively affects the gonadotropin-releasing hormone—luteinizing hormone – testicular axis, leading to inhibition of spermatogenesis before entry of germ cells into meiosis through increased apoptosis and decreased expression of androgen receptors in the testis of the Mozambique tilapia. [ABSTRACT FROM AUTHOR]

Globally, the prevalence and pollution of pharmaceutical drugs in aquatic environments have been steadily increasing. This study sought to evaluate the effects of 14 days of exposure to environmental-relevant doses (ibuprofen 0.5, 5, and 50 µg/L, and carbamazepine 0.005, 1, and 10 µg/L) of the nonsteroidal anti-inflammatory drugs ibuprofen and carbamazepine in the freshwater fish Oreochromis mossambicus. The results showed a significant (P < 0.05) decrease in O. mossambicus superoxide dismutase, catalase, biotransformation enzymes, glutathione-s-transferase, glutathione peroxidase, oxidative stress lipid peroxidation, protein carbonyl activity, cellular damage metallothionine, reduced glutathione, immunological activities, and respiratory burst activity. Consequently, the acquired data revealed that O. mossambicus treated with ibuprofen and carbamazepine shows more significant alterations in metabolic depression, biochemical parameters, and oxidative stress. In addition, increased neurotoxic effects were observed in ibuprofen and carbamazepine treated O. mossambicus. [ABSTRACT FROM AUTHOR]

AbstractThe main objective in this study was to evaluate full-fat Stinkbug as an alternative protein source in the diet of Oreochromis mossambicus. Five diets were formulated to partially replace fishmeal at 0, 10, 30, 50, and 70% levels and were denoted as D1, D2, D3, D4, and D5, respectively. The diets were formulated to be isonitrogenous, isocaloric, and isolipidic. Each diet was fed to triplicate groups of fish for 8 weeks. All growth performance indices declined with an increase in Stinkbug meal inclusion. The specific growth rate declined from 2.16% in the control to 1.28% in D5 (P 0.05) across diets D1 to D4. No histological alterations were evident in the liver and intestine across diets. It was therefore concluded that Stinkbug meal may partially replace fishmeal at 30% replacement level in the diet of O. mossambicus without adverse effects on growth performance and nutrient utilisation indices.

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The combined yields of Oreochromis mossambicus and fruit crops – tomato, sweet pepper, and cucumber were investigated in a low-cost designed gravel bed aquaponic system to maximize overall yield. This study was modeled according to bioeconomic principles, which analyzed the experimental setup's system design and management, biological characteristics, and economic performance. The study was conducted from March 2018 to February 2019. The growth performance of fish was determined using growth rate parameters, length–weight relationship, and condition factor. The effect of plant density and plant stem pruning was used to determine plant yield. Tomato, sweet pepper, and cucumber were subjected to two plant densities (5 and 8 plants.m2). Tomato and cucumber plants were pruned to one and two stems, while sweet pepper plants were pruned into two and three stems. A complete randomized design in triplicate was used. The FCR of 1.25; 97.5% survival rate; specific growth rate of 1.64%, LWR r2 of 0.945, regression coefficient b of 3.1 and condition factor K of 1.93 were recorded for the fish performance. Total yield, marketable yield, unmarketable yield, fruit mass, and number fruits.m2 were recorded. Tomato and cucumber plants pruned into two stems produced significantly (p <.05) higher total and marketable yields than plants pruned to one stem. Sweet pepper plants pruned into three stems produced significantly (p <.05) higher total and marketable yields than those pruned into two stems. A plant density of 8 plants.m2 produced a higher (p <.05) total and marketable yield of tomatoes, sweet peppers, and cucumbers than 5 plants.m2. Biomass yield in aquaponics can be optimized for higher economic viability by manipulating environmental conditions, adopting strategic culture management practices, and targeting higher market prices through scheduled production. [ABSTRACT FROM AUTHOR]

Background: Triclosan is an antimicrobial agent which enters into the aquatic environment through wastewater discharges which causes potential health risk in human and aquatic organisms. The present study aimed to determine the toxic effects of triclosan on Oreochromis mossambicus. Methods: The fishes were subjected to five different concentrations viz. 131, 262, 523, 1046 and 2092 µg.l-1 of triclosan for 96 h acute toxicity test. To evaluate the levels of enzymes such as acetylcholinesterase and glutathione S transferase, brain and liver tissues were collected, homogenized, extracted and stored at -20°C for further analysis. The DNA damage was assessed in gill and liver tissues using single cell gel electrophoresis method. Result: In present study, the calculated 96 h LC50 value of triclosan in O. mossambicus was 740 µg.l-1 and the fishes showed various behavioural alterations. Time and dose dependent inhibition of AChE activity in brain tissue was observed during acute toxicity test. However, the GST activity in liver tissue increased on exposure to triclosan with significant increase in concentration of toxicant. DNA damage index was higher in gill tissue compared to the liver tissue during acute exposure to TCS which could cause detrimental effects in fishes. [ABSTRACT FROM AUTHOR]

Acipenser baerii (Siberian sturgeon) is native to Kazakhstan and is currently endangered and is listed within the first class of protected animals. Sturgeon aquaculture is becoming an important tool for the recovery of this endangered species. Nonetheless, diseases involving typical symptoms of skin ulceration and systemic bacterial hemorrhagic septicemia have occurred in cultured A. baerii on a fish farm located in Western Kazakhstan. In this study, an infectious strain of bacteria isolated from an ulcer of diseased A. baerii was identified as Aeromonas salmonicida (strain AB001). This identification involved analyses of 16S rRNA, gyrB, rpoD, and flaA genes’ sequences. Even though strain AB001 belongs to A. salmonicida, it exhibited noticeable mobility and growth at temperatures of ≥37 °C. Profiling of virulence genes uncovered the presence of seven such genes related to pathogenicity. Antibiotic sensitivity testing showed that the strain is sensitive to aminoglycosides, amphenicols, nitrofurans, quinolones, and tetracyclines. Half-lethal doses (LD50) of strain AB001 for Oreochromis mossambicus and A. baerii were determined: respectively 1.7 × 108 and 7.2 × 107 colony-forming units per mL. The experimentally induced infection revealed that strain AB001 causes considerable histological lesions in O. mossambicus, including tissue degeneration, necrosis, and hemorrhages of varied severity.

The formation of stable periphyton communities is undesirable for all types of hydrotechnical systems, especially functioning watercooling systems. To combat the development of biological fouling in the cooling ponds of nuclear power plants bioreclamation species are widely used, which include Mozambican tilapia. It was unintentionally brought into the cooling reservoir of the Novovoronezh nuclear power plant; however, it formed a stable and numerous population there. The food base for the fi sh population in the cooling pond is depleted due to diffi cult (sometimes extreme) environmental conditions, which can lead to competition for food items. Under these conditions, tilapia switches to feeding on bacterial-algal mats, which develop abundantly in the warm-water part of the reservoir. In areas eaten by tilapia, the biomass of fouling is reduced by one and a half times and the content of mineral substances decreases. The study of the contents of the intestines of tilapia made it possible to confi rm these observations, since representatives of the phytoperiphyton were found in the food bolus: cyanoprokaryotes, diatoms and green algae, for which even a taxonomic affi liation was established. The results of the research made it possible to clarify the mechanism o f integration of this southern species into the ichthyocenosis of the reservoir and its positive role in reducing biofouling.

Microplastics (MPs) are prevalent in nature due to the proliferation of plastic in the environment. However, the presence of microplastics in lakes is largely unknown in comparison to other aquatic bodies. This study was performed to evaluate the abundance and characteristics of MPs in water, sediment, and fish from three major urban lakes in Dhaka, Bangladesh, namely Dhanmondi, Gulshan, and Hatir Jheel lake. The highest concentrations of microplastics in surface water (36 items/L), sediment (67 items/kg), fish (17 items/individual), and the gastrointestinal tract (4.88 items/gm) were observed. Highest abundance of microplastic in an individual fish was observed in Oreochromis mossambicus from Dhanmondi Lake. The samples were visually examined using stereomicroscope and SEM, which revealed that films were the most prevalent kind of microplastics in both the water and the sediment samples, whereas pellets and foams predominated in the fish samples. Visual observation also revealed MPs dominated by

In this study, changes of erythrocyte morphology of Tilapia (Oreochromis mossambicus, L.1758) exposing to the different concentrations of lead have been investigated. Fish were exposed to low (0,5 mg L-1), medium (2,5 mg L-1) and high (5 mg L-1) lead concentrations semi-statically during 14 days. At the end of the experiment, important changes in the treatment groups exposed to medium and high lead concentrations were shown than the control group (p<0.05). Medium and high doses of lead red blood cell nucleus area, an important reduction in the length and width compared to the control, while the width of the cell cytoplasmic space and the control group showed a significant increase (p<0.05). It was concluded that increasing lead concentrations might cause hypertrophy, anisocytosis and cariopicnosis in erythrocyte cell morphology of O. mossambicus. [ABSTRACT FROM AUTHOR]

The stress induced effect of pulp and papermill effluent in the fish, Oreochromis mossambicus was investigated in the present study. Pulp and papermill effluent discharged from Hindustan News Print LTD, Peruva, Kottayam (Dist), Kerala was collected from the discharging point and used for the study. The adult Oreochromis mossambicus of size 15 ± 2 g were exposed to a sublethal concentrations (1/5th and 1/10th LC50 value) of the effluent for a period of 10, 20 and 30 days. biochemical parameters in the liver such as carbohydrate, protein, lipid and enzymes were analysed. Energy yielding nutrients such as carbohydrates, proteins and lipids were decreased tremendously for the study as the concentration and duration of the effluent exposure increased. Increased activity of enzymes such as GOT, GPT and LDH showed that the fish was under stress when exposed to pulp and papermill effluent. Fish exposed to papermill effluent showed reduced activity of ACP and ALP as the duration of exposure and concentration increased.

Saline-alkalinity is one of the important ecological parameter that has an impact function on the physiological metabolism, osmoregulation, survival, growth, development and distribution of teleost fish. Oreochromis mossambicus, a species of euryhaline that can withstand a wide variety of salinities, may be used as a research model animal in environmental studies. In order to detect the metabolism responses and mechanisms of different osmotic stresses tolerance in the gills of O. mossambicus, in present study, the metabolic responses of O. mossambicus subjected to salinity (25 g/L, S_S), alkalinity (4 g/L, A_S) and saline-alkalinity stress (salinity: 25 g/L, alkalinity: 4 g/L; SA_S) with the control environment (freshwater, C_S) were investigated by LC-MS/MS-based metabolomics. The metabolism results indicated that numerous metabolites were identified between the stress groups and the control group. In addition, under three osmotic stresses, the amino acid and carbohydrate metabolism, levels of amino acids, osmolytes and energy substances, such as L-lysine, arachidonic acid, docosahexaenoic acids, creatine and taurine, were significantly affected and changed in the metabolism of the gills of O. mossambicus. The metabolism data indicated that signal transduction and regulation pathways, including FoxO signaling pathway, mTOR signaling pathway and prolactin signaling pathway, were enriched in the gill during adaptation to high salinity, alkalinity and saline-alkalinity stress. The results of this study provide more comprehensive and reliable data for the osmotic pressure regulation mechanism and biological response of euryhaline teleost, and provide reliable scientific basis for the breeding and research of high salinity tolerance population, and further promote the development and utilization of saline-alkalinity water resources.

Extensive use of nanotechnology in multiple commodities is raising concerns about nanotoxicity. In particular, many studies have reported the health-hazardous effects of titanium dioxide nanoparticles (TiO2-NPs). The present study focuses on the toxicity and accumulation of TiO2-NPs in tilapia (Oreochromis mossambicus). For this purpose, tilapia was kept in water tanks, acclimatized for 14 days, and treated with different doses of TiO2 nanoparticles: 0, 0.5, 1.0, and 1.5 mg TiO2-NPs/L. Results revealed an increase in the accumulation of TiO2-NPs with an increase in doses. Moreover, with a higher dose (1.5 mg/L), gills had maximum levels compared to muscles and liver tissues, whereas other doses showed different accumulation patterns. Catalase, glutathione, and lipid peroxidation levels were significantly higher in the gills, and superoxide dismutase levels were significantly higher in the liver. Characteristics like thickening and fusion in lamellae, rupturing of gill filaments, and hyperplasia of gills were also recorded. The phenomenon of increased necrosis and apoptosis in the liver was also noticed with increasing concentration of TiO2-NPs along with the formation of sinusoid spaces and condensed nuclear bodies. Elevated values of olive tail movement and % tail DNA were also noticed with an increased concentration of TiO2-NPs. This study concluded that TiO2-NPs produced oxidative stress by accumulation in soft tissues and induced pathology and genotoxicity. [ABSTRACT FROM AUTHOR]

Mozambique tilapia Oreochromis mossambicus (Peters) is an invasive fish and a continuous breeder in inland waters of India. Present investigation highlights the distinct developmental stages of developing ovary and associated changes in the energy content. This investigation helps to understand the allocation of energy for development of eggs, prespawn and also oral brooding by the female. Although it is a continuous breeder, based on size of the ovary, number of eggs, their size and energy content, immature, early maturing, developing, prespawning and spawning stages are clearly noticed. Egg diameter during development of ovary varied between 0.31 mm (immature) and 2.21 mm (spawning). Energy content of ovary from immature to spawning stage ranged from 20.7515 kJ g−1 dry ovary to 31.1560 kJ g−1 dry ovary. Nearly 28.73% of energy content of ovary is expended for spawning. Similarly, yolk‐sac fry utilized nearly 25.85% of energy of the fertilized egg for its development. Energy content of ovary of mouth‐brooding female averaged 22.9528 kJ g−1 dry ovary, which is comparable to energy content of early maturing stage of ovary (24.5558 kJ g−1 dry ovary). A strong correlation between body weight and energy content of the developing ovary (P < 0.01), and between ovary weight and energy content of ovary (P < 0.01), was evident. During mouth‐brooding, the fish continues to allocate energy to its developing ovary. Energy investment by the fish is the result of simultaneous processes associated with gonadal and somatic energy. As body size growth and gonadal development are interconnected, information on energy utilization by an iteroparous mouth‐brooding fish could provide the pattern of energy allocation during ovarian developmental phase. Further details of energy utilization, as explained in this paper, could be used as one of the factors to predict the efficiency of fish production. [ABSTRACT FROM AUTHOR]

Vanadium (V) is a toxicant becoming increasingly concentrated in freshwater with the potential to affect aquatic organisms. Vanadium pentoxide (V2O5), accumulated in fish, can act as an oxidizing agent and cause oxidative damage. To determine the effects of V2O5 on exposed adult Oreochromis mossambicus, acute exposure experiments were conducted. Bioaccumulation and biomarker analyses were performed on various excised tissues of the exposed fish. As expected, accumulated V concentrations in the gills increased as the exposure concentration increased. Gill tissue accumulated more vanadium than muscle tissue. Metallothionein content increased in the highest concentrations compared to the lower concentrations, therefore showing that metallothionein proteins were attempting to sequester V2O5 in the tissues. Superoxide dismutase (SOD) showed an excitation at lower concentrations and inhibition as the exposure concentrations increased, possibly due to ROS detoxification. Catalase activity decreased from the first exposure concentration to the last concentration; this could have been due to SOD compensation. Protein carbonyl concentration decreased as the concentrations of V2O5 increased, indicating an inhibition of protein oxidation. The IBRv2 comparison revealed the biochemical responses caused by V2O5 more effectively than traditional statistical analysis. [ABSTRACT FROM AUTHOR]

Silicon dioxide nanoparticles (SiO2-NPs) have a wide range of applications in many industrial products, while its ubiquitous applications concern about the toxic effects to aquatic biota. The sublethal effects of SiO2-NPs on the hepatic biotransformation response in freshwater fish remain poorly understood. The aim of this study was to evaluate the hepatotoxic and biotransformation responses in the freshwater fish, Oreochromis mossambicus (Peters, 1852) after SiO2-NPs exposure. A semi-static test system was used to expose the fish to sublethal concentration of SiO2-NPs at 12 mg L− 1 for up to 30 d along with the control group. The activity of ethoxyresorufin O-deethylase (EROD), the most sensitive enzyme to detect the inductive response of the cytP450 system was increased in a time-dependent manner after the nanoparticles exposure. Fish exposed to SiO2-NPs increased the activity of UDP-glucuronosyltransferase (UGT) enzyme in hepatic microsomal fractions illustrating the formation of glucuronide conjugates. The inhibition of monoamine oxidase enzyme revealed the inactivation of monoaminergic neurotransmitters in the fish, which in turn could modulate the liver functions. A reduction in the activity of glutathione S-transferase in the hepatic cytosolic fractions indicated failure of the detoxification pathway. Liver tissue damage was represented by a decline in the activities of aspartate and alanine aminotransferase enzymes in cytosolic fractions. The study concluded that the detoxifying enzymes involved in metabolic reactions are altered on exposure to silica nanoparticles at subcellular level in the liver tissues of the fish, O. mossambicus. [ABSTRACT FROM AUTHOR]

Fish are generally known to change their nutritional requirements depending on their life stage and formulating feeds for different size groups to meet their dietary needs is essential. This study aimed to assess the potential of Crocodylus niloticus meat meal as an animal protein source replacing fishmeal in Oreochromis mossambicus diets. Ten fry (0.07 g fish−1) were randomly assigned to three formulated diets (0% (D1), 50% (D2), and 100% (D3)), and each diet had three replicates. The fry were fed 10% body weight per day (BWd−1) for 30 days. New diets (0% (D4), 50% (D5), and 100% (D6)) were introduced, and the feeding rate was reduced to 5% BWd−1 for 48 days. After that, the fish were fed 2% BWd−1 for 78 days, the same diets used for fingerlings. All size groups were fed two portions of their daily ration at 10:30 h and 15:30 h. Our results point to the suggestion that Crocodylus niloticus meat meal may replace fishmeal for Oreochromis mossambicus, as there were no significant differences in weight gain (G), specific growth rates (SGR), gross feed conversion ratios (GFCR), or protein efficiency ratios (PER) for fry fed different diets. Furthermore, there were similarities in Gs, SGRs, GFCRs, and PER in fingerlings and sub adult to adult fish fed D4 and D5. The cost analysis of ingredients used in diets with 50% and 100% Crocodylus niloticus meat meal indicated that it was profitable to use this meat meal in diets of O. mossambicus of all groups. The profit index of 0.3 for fry, 0.8 for fingerlings, and 1.9 for subadults to adults for 100% fishmeal diets were lower than 0.4 and 0.5 for fry, 0.9 and 1.1 for fingerlings, and 2.3 and 2.9 for sub adult to adult fish fed diets with 50% and 100% crocodile meat meal, respectively. [ABSTRACT FROM AUTHOR]

Toxicological effect of pulp and papermill effuent in the fish, Oreochromis mossambicus was investigated in the present study. Pulp and papermill effluent discharged from Hindustan News Print LTD, Peruva, Kottayam, Kerala were collected and adult fish of size 15±2 g were exposed to a sublethal concentrations (1/5th and 1/10th LC50 value) of the effluent for a period of 10, 20 and 30 days. Pathological conditions such as fatty degeneration (FD), pyknosis (P), haemosiderosis (HS), degenerated renal tubule (DRT) and Vacular hypertrophy of tubular epithelium (VHT). Fatty degeneration (FD) was observed in both concentrations of 10, 20 and 30 days of exposure. Pyknosis (P) was started from 1/5th concentration of 10 days exposed fishes. In experimental fishes haemosiderosis (HS) was found in 1/5th concentration of 20 days and both concentrations of 30 days. Degenerated renal tubule (DRT) was observed in both concentrations of 30 days of papermill effluent exposed fishes. Vacular hypertrophy of tubular epithelium (VHT) and haemosiderosis (HS) was found in 1/5th concentration of 30 days effluent exposed fishes. The present study revealed that the histopathological conditions affect the physiological functions such as metabolic processes and excretion. [ABSTRACT FROM AUTHOR]

Aquaculture in Mozambique was introduced in the late 1950s, and several strategies have since been put in place to develop the sector, especially in growing the Mozambique Tilapia (Oreochromis mossambicus). The study assessed aquaculture production in the Gaza Province of Mozambique. Data was obtained from semi-structured interviews and questionnaires in companies, community associations, and individuals focusing mainly on their adopted production systems, challenges, and opportunities. The study identified 15 fish farmers, with a total of 301 fish culture facilities in which 86% were ponds and 14% cages with cultivation structure varying from 120 m2 to 2000 m2 for ponds and 6 m3 to 13 m3 for cages. Two production systems were distinguished including extensive and semi-intensive with 61% and 39% respectively. Oreochromis niloticus was the main cultured species. These farmers get their feed from Livestock Feed Limited (LFL) and AquaPlus. The unavailability of quality feed, seed and inadequate extension workers were listed as the main challenges faced by the farmers leading to low fish production. Our findings clearly show that fish farming is an attractive activity for small and medium-scale farmers, and it can grow especially if necessary measures are taken to improve management, access to inputs, and extension services.

Fish is a rich source of proteins for humans and is widely consumed in various places in the world. This study assessed the levels of twenty trace metals (B, Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Sr, Mo, Cd, Sn, Sb, Ba, Hg and Pb) in fish feeds (n = 2), water (n = 27), and edible muscles of Oreochromis mossambicus (n = 20 from 8 ponds) from fish farms and Luvuvhu River (n = 3 from 1 river site) in Vhembe district of Limpopo Province, South Africa. Physicochemical parameters of water in the study area were analysed. Temperature ranged between 21.4–30.47 °C, pH: 5.59–7.28, electrical conductivity: 608–1216 μS/cm, total dissolved solids: 156–675 mg/l, dissolved oxygen: 0.28 - 0.56 mg/l, turbidity: 3.92–356.7 NTU, respectively. Levels of most trace metals such as Cr (2 μg/l and 1000 μg/kg), Mn (100 μg/l and 500 μg/kg), Fe (10 μg/l and 300 μg/kg), Ni (20 μg/l and 100 μg/kg), As (50 μg/l and 3 μg/kg), Pb (10 μg/l and 300 μg/kg) and Cu (2 μg/l and 2250 μg/kg) in water and O. mossambicus muscles were mostly below the World Health Organization (WHO), Food and Agricultural Organization (FAO)/WHO and European Commission (EC) recommended limit in the collected samples (Tshifulalani site and Duthuni site). However, Cu and Fe recorded concentration above the recommended limit at the control site (Luvuvhu River) in water and O. mossambicus muscles, respectively. Results from the bioaccumulation factor (BF), suggests the presence of metals in the water which can bioaccumulate in the fish muscles. Most of the metals (As, Cd, Hg, Mo, Sr, Sb and Sn) that recorded no possible bioaccumulation also recorded levels that complied with their maximum permissible limit (MPL) of WHO, FAO/WHO and EC guideline values in the fish feeds except for Se and Co. Moderate bioaccumulation was recorded for Cr, Mn, Fe and Zn in some of the sampling sites. Pb and Ni showed extreme bioaccumulation (BF > 5000) in one of the sampling sites and also recorded elevated levels in the fish feeds. Average daily dose (ADD), hazard quotient (HQ) and total hazard quotient (THQ) computed were less than 1. The Cancer risk (CR) evaluated were all below 10−4 except in one site for children (Tshifulanani 2) but the overall average result showed no carcinogenic health risk to the consumers of the O. mossambicus. Therefore, O. mossambicus intake in the study area should be constantly monitored to prevent future health implications.

Acute toxicity of arsenic to Tilapia (Oreochromis mossambicus) and tissue repairing activity of Glycosmis pentaphylla leaf extract and its histological impacts on gill, liver, and kidney tissues were evaluated. Fish were divided into six groups viz. control, group 1, group 2, group 3, group 4, and group 5. 4.87 ppm of NaAsO2 was administrated in group 1, group 3, and group 5. In group 3, after arsenic exposure, 2.5 g of leaf extract of Glycosmis pentaphylla per kg of fish food was added. In group 5, 5g of G. pentaphylla leaf extract per kg of fish food was added. In group 2, 2.5 g of leaf extract per kg of fish food was added and in group 4, 5g leaf extract per kg of fish food was added. The control group showed normal histology of the gill, liver, and kidney. The histological observations revealed the tissue repairing activities in group 2 fish's gill, liver, and kidney. These results revealed the protective and tissue repairing potential of G. pentaphylla as a feed supplement against NaAsO2 induced toxicity. [ABSTRACT FROM AUTHOR]

This paper reports on the seasonal and species comparison of hepatic nodular alterations in two indicator fish species from the hyper-eutrophic Roodeplaat Dam in South Africa. This freshwater system is characterized by seasonal cyanobacterial algal blooms which release bio-toxins, including hepato-toxins, which can have negative effects on the health of the resident fish population. A total of 115 Clarias gariepinus (Burchell) and 98 Oreochromis mossambicus (Peters) were collected seasonally across six different surveys over a period of 3 years. Nodular alterations in livers were assessed both macroscopically and microscopically. We found a species difference with a 48% prevalence of nodular alterations in C. gariepinus and no macroscopically visible alterations in O. mossambicus. Affected fish also showed an increase in the ratio of liver mass to body mass, i.e., the hepatosomatic index. The microscopic characteristics of the nodules were primarily associated with pre-neoplastic, focal areas of cellular alterations; most prevalent were focal areas of steatosis. However, we could not establish a seasonal pattern regarding the occurrence of these alterations and therefore no association between the occurrence of the liver pathology and the cyanobacterial blooms. Our results therefore suggest that the occurrence of nodular alterations is not an acute, seasonal response, but rather a chronic, and possibly, and more interestingly, a species-specific, pathological response. [ABSTRACT FROM AUTHOR]

The goal of this study was to assess the acute toxicity and biochemical changes on Oreochromis mossambicus exposed to fungicide Tricyclazole. Within the acute toxicity test, 96hr LC50 values of Tricyclazole were assessed to be 13.2 ppm, and biochemical parameters such as carbohydrate and glycogen levels were found to be dose-dependent decreases in all experimental groups, whereas cholesterol and protein levels were found to be dose-dependent increases in all experimental groups. The changes within the biochemical alterations in Oreochromis mossambicus can be used as the warning indications that their existence in their natural environment may be jeopardized. Hence, the current study reveals that the employment of Tricyclazole 75% pesticide product was classified among substances harmful to fish. The buildup of the fungicide within the muscle tissue in fishes might be hazardous to living organisms. [ABSTRACT FROM AUTHOR]

In this study we investigated the acute toxicity of Zinc Nano Particles (ZnO NPs) and bulk ZnO on tilapia fish (Oreochromis mossambicus). Oreochromis mossambicus was exposed to the different concentration of ZnO NPs, ZnO and mixed solution of both ZnO NPs and ZnO (20 ppb, 20 ppb, 20 ppb) respectively for 96 h. A very high impact was recorded in hematological parameters which shows significant increased (p < 0.05) in count of white WBCs and platelets in all the experimental groups compared tocontrol group. The count of RBCs, Hb, hematocrit and MCHC were significantly decreased. The remarkable changes which were recorded during this study were histopathological lesions in the gills of exposed fish including, disorganization of gill lamella, cartilaginous core disruption, lifting of epithelium, loss of secondary gill lamellae, blood congestion, fusion of secondary gills lamellae, shortening of secondary gills lamellae, atrophy and curling. Disassembly were seen in plasma membrane of liver along with blood congestion, pyknosis, necrosis, hyperplasia and formation of vacuoles. Intestinal alterations which were observed include shortening of villi, necrosis, detachment and fusion of villi and extreme goblet cells formation. It is concluded from the present study that high level of ZnO NPs, ZnO and mixed solution has a strong tendency to alter hematological parameters, histological architecture, therefore, the indiscriminate use of ZnO NPs and ZnO can subsidize in reducing the population of Oreochromis mossambicus in natural water bodies. [ABSTRACT FROM AUTHOR]

The effect of Alfalfa leaf meal supplemented diet was evaluated on the growth of Oreochromis mossambicus fingerlings. Five levels of experimental diet T1, T2, T3, T4 and T5 containing alfalfa leaf meal at the rate of 5%, 10%, 15%, 20% and 25% and control diet (T0 ) were fed for 60 days. The experimental fishes were fed at a rate of 4 per cent of body weight. The experimental results show significantly different (P<0.05) between the treatment and control. The highest weight gain (28.43±0.66 g), percent weight gain (163.74±3.91%), net gain in length (1.418±0.008cm), specific growth rate (1.62±0.03%) and gross conversion efficiency (GCE) (0.432±0.007) were observed in treatment T4 and the lowest value was recorded in T0 control. The treatment T4 showed higher food utilization and low food conversion ratio (FCR), i.e. 2.909±0.047, compare to other treatments. These findings indicated that alfalfa leaf meal at the rate of 20 per cent in the fish diet has a beneficial impact on the growth of fingerlings of Oreochromis mossambicus. [ABSTRACT FROM AUTHOR]

The aim of this investigation was to examine the influence of temperature on testicular activity in the continuously breeding fish Oreochromis mossambicus. The fish were subjected to natural temperature (controls; 21.95 ± 0.21 °C), and low water temperature (LT; 18.18 ± 0.17 °C) or high water temperature (HT; 34.66 ± 0.31 °C) for an experimental period of 21 days, following which they were euthanized and the testes examined. The mean number of spermatogonia was significantly higher in fish exposed to the HT treatment than in the controls and fish exposed to the LT treatment. However, a significant reduction in the mean number of primary spermatocytes, secondary spermatocytes, early spermatids and late spermatids was observed in fish subjected to the LT and HT treatments compared to the controls. In addition, the mean serum testosterone levels were significantly decreased in fish exposed to the LT and HT, whereas the serum cortisol levels were significantly higher in these fish groups compared with the control fish. Taken together, these results suggest that exposure of fish to LT or HT activates the neuroendocrine axis that regulates the stress respone, leading to the inhibition of the process of spermatogenesis, possibly through the suppression of testicular steroidogenesis in O. mossambicus. [ABSTRACT FROM AUTHOR]

In this investigation, we examined the influence of alpha-melanocyte stimulating hormone (α-MSH), a proopiomelanocortin-derived peptide, along the hypothalamic-pituitary-gonad axis in a cichlid fish Oreochromis mossambicus. Administration of α-MSH (40 µg/0.1 ml saline) for 22 days did not affect the number of stage I (previtellogenic) follicles but caused significant reduction in the mean numbers of previtellogenic (stages II and III), vitellogenic (stage IV) and preovulatory (stage V) follicles compared to those of controls. While the gonadosomatic index was significantly lower, the rate of follicular atresia in stages II, III and IV remained significantly higher in α-MSH-treated fish compared to the controls. Furthermore, the mean percent area of gonadotropin-releasing hormone-immunoreactive (GnRH-ir) fibres and luteinizing hormone-immunoreactive (LH-ir) cells were significantly reduced in the proximal pars distalis of the pituitary gland in α-MSH-treated fish compared with the controls. Together, our findings suggest for the first time that the treatment of α-MSH blocks the follicular developmental process during the ovarian cycle, possibly through the inhibition of GnRH-LH pathway in teleosts. [ABSTRACT FROM AUTHOR]

The occurrence of fish diseases contributes to massive economic loss to the aquaculture industry. Edwardsiella tarda, a known pathogenic organism in Oreochromis mossambicus, infects several freshwater fishes. The present study attempts to find an effective treatment against E. tarda infection using natural plant-based bioproducts. Tamarindus indica seed extract was used to study its antibacterial activity against E. tarda. The study revealed that the petroleum ether extract and ethanolic extracts were effective in controlling the infection. It was found to be effective in both in vitro and in vivo. A maximum zone of inhibition, i.e., 9 and 24 mm, was recorded when 40μL of the petroleum ether extract and 40 μL of the ethanolic extract were loaded separately in the well against the test organism. Results showed that the petroleum ether and ethanol extract of T. indica seed were effective in treating the E. tarda infection. [ABSTRACT FROM AUTHOR]

Nanotechnology has shown rapid progress in various fields which had made a remarkable change in the field of therapeutics too. Current study was designed to evaluate comparative remedial effects of water borne Moringa oleifera seed extract (MO-SE) and Trigonella foenum-graecum seed extract (TFGSE) against CuO-NPs induced toxicity in Oreochromis mossambicus through histological and oxidative stress analysis. The study involved 80 fish (20-25g) randomly distributed into eight groups (10 fish/group) as negative control (NC=no-dose), positive control (PC=0.12mg/l CuO-NPs) and six cotreated groups of seed extracts plus CuO-NPs. MOSE plus CuO-NPs co-treated groups were named as Gl, G2 and G3 treated with MO-SE @ 32, 48 and 96mg/l along with 0.12mg/l of CuO-NPs, respectively. Whereas, TFG-SE plus CuO-NPs co-treated groups were designated as G4, G5 and G6 treated with TFG-SE @18, 26 and 52 mg/1 along with 0.12mg/l CuO-NPs, respectively. In this study, significant remedial effects (p < 0.05) were found in G2, G3 and G6 groups with respect to antioxidant enzymes (reduced Glutathione, Lipid peroxidase, Malondialdehyde and Catalase) and histological analysis of gills and muscles. It was revealed that MO-SE was a strong healer compared to the TFGSE. In this study it was concluded that MO-SE was better to ameliorate toxic effects of CuO-NPs in O. mossambicus as compared to TGF-SE and is the first to investigate the comparative ameliorative effects of both Moringa oleifera and Trigonella foenum-graecum seed extract against CuO-NPs in fish. [ABSTRACT FROM AUTHOR]

Fish are generally known to change their nutritional requirements depending on their life stage and formulating feeds for different size groups to meet their dietary needs is essential. This study aimed to assess the potential of Crocodylus niloticus meat meal as an animal protein source replacing fishmeal in Oreochromis mossambicus diets. Ten fry (0.07 g fish−1) were randomly assigned to three formulated diets (0% (D1), 50% (D2), and 100% (D3)), and each diet had three replicates. The fry were fed 10% body weight per day (BWd−1) for 30 days. New diets (0% (D4), 50% (D5), and 100% (D6)) were introduced, and the feeding rate was reduced to 5% BWd−1 for 48 days. After that, the fish were fed 2% BWd−1 for 78 days, the same diets used for fingerlings. All size groups were fed two portions of their daily ration at 10:30 h and 15:30 h. Our results point to the suggestion that Crocodylus niloticus meat meal may replace fishmeal for Oreochromis mossambicus, as there were no significant differences in weight gain (G), specific growth rates (SGR), gross feed conversion ratios (GFCR), or protein efficiency ratios (PER) for fry fed different diets. Furthermore, there were similarities in Gs, SGRs, GFCRs, and PER in fingerlings and sub adult to adult fish fed D4 and D5. The cost analysis of ingredients used in diets with 50% and 100% Crocodylus niloticus meat meal indicated that it was profitable to use this meat meal in diets of O. mossambicus of all groups. The profit index of 0.3 for fry, 0.8 for fingerlings, and 1.9 for subadults to adults for 100% fishmeal diets were lower than 0.4 and 0.5 for fry, 0.9 and 1.1 for fingerlings, and 2.3 and 2.9 for sub adult to adult fish fed diets with 50% and 100% crocodile meat meal, respectively.

This study was conducted to assess the histopathological changes in liver and intestine and serohepatic biochemical response of Oreochromis mossambicus induced by nano CuO during 96-hrs of LC 50 Assessment. The trial was conducted at fish laboratory of Government College University Faisalabad Pakistan. The experimental fish (n=60, weight approx. 5 grams) were divided into 6 aquariums (n=lO per aquarium). Each group was treated with different concentrations of nano CuO as A (0.00), B (0.8), C (1.00), D (1.20), E (1.60), and F (2.4) mg/L. The fish were observed for physical symptoms appear during 96 hours and dead fish was immediately dissected after mortality to collect liver and intestine for histological analysis. Serum was also collected from each fish before mortality to assess the hepato-biochemical changes. Alive fish remained after 96 hrs were dissected to proceed further analysis. This study approach was not previously reported in five-year literature especially for the assessment of LC50 of Oreochromis mossambicus and initial physiological changes to experiment with further studies. [ABSTRACT FROM AUTHOR]

Microalgae like Spirulina (Arthrospira platensis) are protein rich and can be alternative protein sources to fishmeal and soybean meal in fish feed formulation. The present study aims to improve the protein bioavailability of Spirulina by cost-effective protein extraction followed by protease supplementation in fish feed, using in vitro studies. Different extraction procedures such as microwave-assisted, high pressure, and temperature-mediated extraction, boiling and an isoelectric precipitation were employed to study the protein yield from Spirulina powder, and this was compared with the conventional soybean meal and fishmeal conditioning during feed manufacture. Bromelain is a potent protease that has not been widely used as a feed additive with Spirulina. To study the comparative efficiency of bromelain and other proteases like papain and trypsin on Spirulina and conventional feed substrates, a protease assay was performed at different temperatures and enzyme concentrations. The digestibility of these substrates was also studied in vitro, using gut extracts from the fingerlings of Mozambique tilapia (Oreochromis mossambicus). Unlike an in vivo feeding trial, a novel method was used to study the effect of protease supplementation on the inherent digestibility of the gut with an in vitro method. Bromelain showed the highest activity on all the substrates at both the temperatures. Bromelain supplementation improved the in vitro digestibility of the Spirulina that were subjected to protein extraction, more than the un-extracted one. The results of the present in vitro study suggest that Spirulina could serve as an alternative protein source, and bromelain-based supplementation could improve the digestibility of Spirulina-based fish diets. [ABSTRACT FROM AUTHOR]

Aquaculture in Mozambique was introduced in the late 1950s, and several strategies have since been put in place to develop the sector, especially in growing the Mozambique Tilapia (Oreochromis mossambicus). The study assessed aquaculture production in the Gaza Province of Mozambique. Data was obtained from semi-structured interviews and questionnaires in companies, community associations, and individuals focusing mainly on their adopted production systems, challenges, and opportunities. The study identified 15 fish farmers, with a total of 301 fish culture facilities in which 86% were ponds and 14% cages with cultivation structure varying from 120 m2 to 2000 m2 for ponds and 6 m3 to 13 m3 for cages. Two production systems were distinguished including extensive and semi-intensive with 61% and 39% respectively. Oreochromis niloticus was the main cultured species. These farmers get their feed from Livestock Feed Limited (LFL) and AquaPlus. The unavailability of quality feed, seed and inadequate extension workers were listed as the main challenges faced by the farmers leading to low fish production. Our findings clearly show that fish farming is an attractive activity for small and medium-scale farmers, and it can grow especially if necessary measures are taken to improve management, access to inputs, and extension services. [ABSTRACT FROM AUTHOR]