In this study,chondroitin sulfate was extracted from Oreochromis niloticus bones(OCS)and isolated to three fractions(OCS-1,OCS-2,and OCS-3).The physicochemical properties and structure characterization including monos...In this study,chondroitin sulfate was extracted from Oreochromis niloticus bones(OCS)and isolated to three fractions(OCS-1,OCS-2,and OCS-3).The physicochemical properties and structure characterization including monosaccharide,disaccharide compositions,molecular weight(Mw)of OCS were determined by HPAEC,HPLC-SAX,HPGPC,FT-IR spectra,and 1D/2D NMR.Moreover,their thermal properties,crystalline structure,and microstructure were also analyzed.Results showed that their Mw were between 10 kDa and 50 kDa.CS-6 was the predominant disaccharide unit in four OCS,and the CS-4/CS-6 ratios were close to CS from shark cartilage.Besides,the results of antioxidant activity showed that different fractions of OCS had a distinct DPPH radical,hydroxyl radical,and ABTS+radical scavenging activity.OCS-1 has the highest scavenging activities in DPPH and hydroxyl radical compared with other fractions,which showed a higher medicinal value.Those findings may lay some theoretical basis for the potential application development of OCS.展开更多
The optimization of aquaculture production requires the selection of efficient strains. Thus, genetic improvement has become one of the important levers to boost the development of aquaculture. The objective of this s...The optimization of aquaculture production requires the selection of efficient strains. Thus, genetic improvement has become one of the important levers to boost the development of aquaculture. The objective of this study was to carry out genetic characterization of Nile tilapia Oreochromis niloticus, one of the most cultivated fish species in Senegal, in order to select an efficient strain to optimize local fish production. Thus, fish from five different populations (Richard-Toll, ANA, ITACA, Mbodiene and Sauvage) were analyzed, with 15 individuals per population. Genetic diversity and population structure were assessed using molecular genetic analyses by sequence characterized amplified region (SCAR) and microsatellite (SSR) markers. The analyses of the SCARII marker were conducted on four populations (ANA, ITACA, Sauvage and Mbodiene) while microsatellite analyses were conducted on all five populations. The results show high levels of polymorphism of SSR markers, and a high level of observed heterozygosity (Ho), indicating a high within-population genetic variability. These results are in agreement with the AMOVA results, which indicated a high within-population genetic variability (94%). The genetic structure analysis by DAPC indicates that the five populations analyzed are structured into four groups, which are highly heterogeneous because they share common allele individuals. The analysis of the genetic structure by AMOVA showed a low degree of differentiation between the populations (6%), in agreement with the genetic differentiation index (Fst = 0.059). The heterogeneity of studied populations implies a genetic flow over time, which may have existed between the original populations. The overall negative Tajima D values and low genetic differentiation indicate an excess of rare mutations in the populations studied, resulting from a recent population expansion from a limited number of initial breeders isolated in locale hatcheries. Thus, further studies with a much larger panel of markers are required to better differentiate the strains and identify the most efficient ones for sustainable local aquaculture production.展开更多
This study was carried out in 2022 at the Itato agriculture community estate of fish hatchery in eastern Senegal with the aim of finding an alternative method to 17-α-methyl testosterone (MT) by using Garcinia kola ...This study was carried out in 2022 at the Itato agriculture community estate of fish hatchery in eastern Senegal with the aim of finding an alternative method to 17-α-methyl testosterone (MT) by using Garcinia kola “Bitter kola” powder to obtain Oreochromis niloticus male sex populations. 1800 fry of average size between 0.01 and 0.02 g were distributed in 12 aboveground tanks of 1 m3 each at a rate of 150 individuals/tank, following 6 duplicate treatments. The negative (B1 and B2) and positive (B3 and B4) control diets, to which between 0 and 60 mg/kg of 17alpha-methyl testosterone had been added respectively, were mixed with industrial feed containing 40% protein;the tank diets (B5 and B6), (B7 and B8), (B9 and B10) and (B11 and B12) contained 10 g, 20 g, 30 g and 40 g of Garcinia kola powder respectively for 1 kg of industrial feed con-taining 40% protein. These different treatments resulted in high proportions of males in the order of 97.03%;98.09% for the hormone and proportions of 94.03%;93.26% for 20 g of Garcinia kola extracts. In terms of weight growth, the best average weights for the hormone and Garcinia kola were 0.896 g and 0.980 g respectively. With regard to fish survival, the following results were recorded: 95.53% and 94.56% respectively for additions of 20 g and 30 g of Garcinia kola extracts to the feed supplied to the fish. On the other hand, a significant difference in the mortality rate of 35% and 5% respectively for the conventional hormone and 20 g of Garcinia kola extracts was observed. To conclude the study, it is recommended that further studies be carried out to determine the quality of the flesh, their life stages and the profile of the amino acids present in their proteins.展开更多
Dried fish are susceptible to bacteria and fungi attack and are liable to chemical changes which cause losses in quality and reduction of shelf-life. It is important therefore to maintain the quality of fish because c...Dried fish are susceptible to bacteria and fungi attack and are liable to chemical changes which cause losses in quality and reduction of shelf-life. It is important therefore to maintain the quality of fish because continuous consumption of contaminated fish and their products may predispose consumers to health hazards. Maintenance of high quality fish therefore calls for adequate and effective preservation techniques. The study examined the effectiveness of essential oils of Ocimum basilicum and Ocimum gratissimum from two Agro-ecological zones of Cameroon in limiting the microbial proliferation and preserving the quality of smoke-dried Oreochromis niloticus fish stored at 25˚C for two months. The plant materials were harvested from the Western Highlands and Monomodal Humid Forest agroecological zones of Cameroon. Extraction of the essential oil from the plants was done by hydro-distillation. The fish species (Oreochromis niloticus) used in this study was chosen based on a survey study on the most consumed species of freshwater smoke-dried fish in the Western Highlands and Monomodal Humid Forest Agro-ecological zones of Cameroon. Heterotrophic bacteria counts, fungi counts and Enterobacteriaceae counts were used to assess the level heterotrophic bacteria, fungi and Enterobacteriaceae respectively in the fish samples during storage and were done by culture techniques using total plate count agar, potato dextrose agar and violet red bile glucose agar respectively. Total volatile basic nitrogen, peroxide value, and thiobarbituric acid reactive substance assays were used as spoilage indices to assess the nutritional quality of the fish during storage. From the survey study, Oreochromis niloticus was the most consumed smoke-dried fish in the Western Highlands (35.45%) and Monomodal Humid Forest (34.55%) agroecological zones. All the EOs caused a significant reduction in the microbial loads, total volatile basic nitrogen, peroxide value, and thiobarbituric acid reactive substance of smoke-dried Oreochromis niloticus as storage progressed. However, the reduction in these values was more pronounced in samples treated with essential oils of O. gratissimum from the Western Highlands, with heterotrophic bacteria, fungi and Enterobacteriaceae counts being 5.89, 6.97 and 4.59 log<sub>10</sub> cfu/g respectively at the end of the storage period. This was followed by essential oils of O. gratissimum from the Monomodal Humid Forest with heterotrophic bacteria, fungi and Enterobacteriaceae counts being 6.11, 7.79 and 4.86 log<sub>10</sub> cfu/g respectively at the end of the storage period. Also, essential oils of O. gratissimum from the Western Highlands was more effective in preserving the fish quality as lowest total volatile basic nitrogen (12.29 mg/100g), peroxide value (2.79 mEq O<sub>2</sub>·Kg<sup>−1</sup>) and thiobabituric reactive substance (1.695 mg MDA/Kg) values were observed for fish samples treated with this extract at the end of the storage period. This was followed by essential oils of O. gratissimum from the Monomodal Humid Forest with total volatile basic nitrogen (14.95 mgN/100g), Peroxide value (3.23 mEq O<sub>2</sub>·Kg<sup>−1</sup>) and thiobabituric reactive substance (2.354 mg MDA/Kg) at the end of the storage period. From the results obtained, essential oils from O. gratissimum were more effective than that from O. basilicum in the two agroecological zones and should be considered as natural alternative to chemical preservatives for further application in food preservation.展开更多
Irrigation of fish farms with agricultural drainage water may affect cultured fish species. So, the present study utilizes antioxidants supplemented diet to overcome deterioration of drainage water and its negative ef...Irrigation of fish farms with agricultural drainage water may affect cultured fish species. So, the present study utilizes antioxidants supplemented diet to overcome deterioration of drainage water and its negative effect on fish. The studied groups are fish cultured in dechlorinated tap water as control group or drainage water and fed commercial basal diet. While, the other studied groups represented by Oreochromis niloticus fish cultured in drainage water and fed either commercial diet supplemented with vitamin C (5 g/kg diet) or fennel (5 g/kg diet) for 12 weeks. Results of the water physico-chemical parameters of all studied treatments revealed deterioration of the drainage water with a decrease in dissolved oxygen and an increase in pH, total hardness, total alkalinity, salinity, ammonia, nitrite and heavy metals (Cu, Pb and Cd) with significant differences (P ≤ 0.01) in comparison to that of the control dechlorinated tap water group. Data clarified also that Oreochromis niloticus cultured in drainage water showed a decrease in growth rate accompanied by deterioration of fish meat quality. However, fish reared in the same drainage water for the same exposure period and fed vitamin C or fennel supplemented basal diet (5 g/kg diet) recorded values of the studied parameters more or less similar to that of control group fish. Data of the present study, empowered aquaculturist to supplement fish rations with fennel or vitamin C as antioxidants to improve fish growth rate, meat quality as well as protect fish against heavy metals toxicity that could threat Human Being.展开更多
为比较星洲红鱼(Singapore red tilapia)和奥尼罗非鱼(Oreochromis niloticus)的生长和肌肉营养特性,实验利用两种鱼的不同体色将其混养在同一池塘中,在相同的环境条件和养殖管理下研究其生长特性,并分析肌肉营养成分。结果表明:两种罗...为比较星洲红鱼(Singapore red tilapia)和奥尼罗非鱼(Oreochromis niloticus)的生长和肌肉营养特性,实验利用两种鱼的不同体色将其混养在同一池塘中,在相同的环境条件和养殖管理下研究其生长特性,并分析肌肉营养成分。结果表明:两种罗非鱼生长在前60 d无差异,60 d后星洲红鱼的体长、体质量日增长和特定生长率均大于奥尼罗非鱼,且差异显著(P<0.05)。据此得到了星洲红鱼和奥尼罗非鱼的体长(L)、体质量(W)生长与养殖天数(d)的回归方程。星洲红鱼含肉率高于奥尼罗非鱼9.65%(P<0.05),肌肉水分高于奥尼罗非鱼,蛋白质、粗脂肪和灰分含量均低于奥尼罗非鱼,其中脂肪含量差异显著(P<0.05),其他不显著。两种罗非鱼肌肉的氨基酸组成全面,氨基酸组成均符合FAO/WHO的理想模式,除精氨酸含量有差异外,其他氨基酸含量稍有差异但不显著。星洲红鱼和奥尼罗非鱼肌肉EAA/TAA、EAA/NEAA、DAA/TAA和EAAI分别为41.04%和40.95%,70.00%和69.34%,40.71%和39.08%,67.46%和67.08%,差异不显著。星洲红鱼、奥尼罗非鱼肌肉∑SFA和∑UFA分别为28.03%和28.60%,63.87%和61.38%,各脂肪酸含量除C14:0和C18:2外,其他含量差异不显著。研究表明,星洲红鱼和奥尼罗非鱼生长快、营养丰富、食用价值高,是优质淡水鱼类养殖品种,其中星洲红鱼含肉率高,生长快,养殖效益明显。展开更多
Through PCR amplification, 5' flanking region and partial open reading frame(ORF) of gene of Nile tilapia(Oreochromis niloticus) was cloned by PCR amplification. Sequence analysis showed that no difference was fou...Through PCR amplification, 5' flanking region and partial open reading frame(ORF) of gene of Nile tilapia(Oreochromis niloticus) was cloned by PCR amplification. Sequence analysis showed that no difference was found in known functional regions. This study was to construct and identify the mammalian expression vector of pEGFP-β-actin and to detect whether it could express in HEK 293T cell line. pEGFP-β-actin was transfected into HEK 293T cells with Lipofectamine 2000. The results showed that correct construction of recombinant pEGFP-β-actin has been shown by restriction enzyme digestion. The expression of gene in HEK 293T cells could be observed under microfluoroscope. pEGFP-β-actin could repress EGFP protein in HEK 293T cells. The results showed that β-actin gene promoter possessed effective transcription activities in eukaryotic cells. The work laid foundations for further study on the gene engineering and autotransgenic tilapia.展开更多
Concentrations of OCP(Organochlorine Pesticide)residues were determined in cultured Nile tilapia(Oreochromis niloticus)fish in target stations within 1st order wetland of River Kuja,Kenya,between February-November,201...Concentrations of OCP(Organochlorine Pesticide)residues were determined in cultured Nile tilapia(Oreochromis niloticus)fish in target stations within 1st order wetland of River Kuja,Kenya,between February-November,2017.The aim was to assess the residue levels in wild and pond cultured fish within a heavily populated agricultural area of South Western Kenya.Biota samples were analysed for selected HCHs(Hexachlorocyclohexane)isomers,DDT(Dichlorodiphenyltrichloroethane)and metabolites and cyclodienes pesticide residues using GC-ECD(Gas Chromatography Equipped with Electron Capture Detector).Most of OCPs observed were BDL(Below Detection Limit)to detectable levels.Larger percentages(>50%)of DDTs and HCHs were BDL and exhibited consistency,with significant(p<0.05)differences in mean contamination levels in fish within the wetland,with average muscle tissue pesticides concentrate ranging between 0.229-2.541mg/kg for Nile tilapia.Most dominant isomer in target species was Lindane(g-HCH)(3.417±0.983mg/kg)and Endosulfans.Mean Endosulfan sulfate was 2.499±0.071mg/kg d.w.and most frequently detected,and Methoxychlor(2.235±1.459mg/kg),respectively.Mean Aldrin and Dieldrin was 2.028 and 0.574mg/kg d.w.Concentration for DDT and its metabolites was 0.27-3.71mg/kg for p,p’-DDE(DichlorodiphenylDichloroEthene),BDL-1.098 for p,p’-DDD(DichloroDiphenylDichloroEthane),and 0.105-3.518mg/kg for p,p’-DDT with significant differences in mean values and ranges whose levels were below the WHO(World Health Organization)maximum acceptable thresholds of 0.2,2,20 and 5.0mg/kg in fish and sea food.Interventions and monitoring need up-scaling in minimizing public health risks posed by consumption and exposure.展开更多
This study was designed to investigate the possible variation in bioaccumulation of heavy metals (lead, cadmium, zinc, cobalt, chromium, nickel, and manganese) in the tissue of harvested Oreochromis niloticus (tilapia...This study was designed to investigate the possible variation in bioaccumulation of heavy metals (lead, cadmium, zinc, cobalt, chromium, nickel, and manganese) in the tissue of harvested Oreochromis niloticus (tilapia) and the associated fungi from vials treated with soil from e-waste dumpsite and soil without e-waste. E-waste is electronic waste which contains valuable metals as well as potential environmental contaminants. The heavy metals in soil and fish samples were determined using flame atomic absorption spectrophotometer (AAS) after homogeneity and digestion of samples. The associated fungi were identified using standard microbiological methods. The genera of the associated fungi were: Penicillium, Candida, Articulospora, Aspergillus, Aspergillus, Aspergillus, Rhizopus, Mucor, Zoopage, Varicosporium and Rhodoturula. The quantity of fungi isolated from each pollution treatments showed that the number of fungi were inversely proportional to the quantity of e-waste soil pollution and directly proportional to the quantity of soil without e-waste pollution. The occurrence of the fungi species revealed that the untreated (control) vial had the highest occurrence (191) while the lowest occurrence (103) occurred in the vial polluted with the highest quantity of soil from e-waste dumpsite. The pH and the biochemical oxygen demand (BOD) of the vials were significantly affected by the pollutions. Variations were also observed in the bioaccumulation of the heavy metals by Oreochromis niloticus. Cadmium (0.01 mg/kg) and nickel (0.02 - 0.08 mg/kg) were the least recorded metal in the tissue of the fish while cobalt was not detected after the five weeks period. The sequence of the heavy metals concentrations in Oreochromis niloticus tissue samples was Zn > Mn > Pb > Cr > Ni > Cd > Co. The accumulation of the metals in the fish tissue were, however, lower than the international maximum guidelines, except for manganese (0.29 - 3.13 mg/kg) that exceeded the 0.01 - 0.05 mg/kg threshold levels for manganese by Federal Environmental Protection Agency (FEPA). Protecting the environments from toxic metals is necessary, hence a need for public awareness on the dangers of these toxic metals and law for proper disposal of e-waste.展开更多
We present results of a long-term study aimed to optimize Nile tilapia O. niloticus production in a recirculating aquaculture system (RAS) in México City. Three experiments were evaluated: 1) fry production;2) pr...We present results of a long-term study aimed to optimize Nile tilapia O. niloticus production in a recirculating aquaculture system (RAS) in México City. Three experiments were evaluated: 1) fry production;2) production of masculinized fries;and 3) assessment of growth under three different densities (10, 30 and 75 fish/m3). The broodstock produced on average 2400 ± 600 fry every 15 days during six months, with a total production of 28,800 ± 2000. One hundred percent males were produced in 274-L raceways in an eight-week period. The obtained results in fish production in the RAS system indicated variations related to density. A daily growth rate of 3.6 g/day was registered with a density of 10 fish/m3, 0.9 g/day in 30 fish/m3 and 0.4 g/day in 75 fish/m3. This information could be useful for production purposes in this type of systems.展开更多
Since amateur fishing in fishponds has been on the increase in Brazil, there is a great concern on the microbiological quality of fish. One hundred and thirty-eight samples were collected during the dry and rainy peri...Since amateur fishing in fishponds has been on the increase in Brazil, there is a great concern on the microbiological quality of fish. One hundred and thirty-eight samples were collected during the dry and rainy periods in ten fish farms. Aeromonas spp. counts and tests for sensitiveness to antimicrobials were performed, coupled to the physical and chemical analyses of water. Tests revealed that 70% of samples were contaminated by Aeromonas spp., with water averaging 2.92 Log CFU/100 mL during the rainy period and 3.16 Log CFU/100 mL during the dry one. Fish contaminated by Aeromonas spp. averaged 2.58 Log CFU/100 mL during the rainy period and 3.53 Log CFU/100 mL during the dry one. Aeromonas spp. samples were multi-resistant to 2 or 8 antimicrobials in 62.5% of the samples. Ampicillin was the antimicrobial with the highest resistance percentage rate. Results showed that fish bred in amateur fish farms constituted a health risk for the population.展开更多
Ethidium bromide(EtBr)is one of the contaminants recorded in aquatic environments whose effects have been investigated;however,there is still limited knowledge about its remediation.This study examined the potential p...Ethidium bromide(EtBr)is one of the contaminants recorded in aquatic environments whose effects have been investigated;however,there is still limited knowledge about its remediation.This study examined the potential protective effects of Spirulina platensis(SP)against the effects of EtBr toxicity in the Nile tilapia(Oreochromis niloticus)fry.Fry were divided to five groups,viz.,a control and four treatment groups of low-dose EtBr(10μg/L),low-dose EtBr with SP(10μg/L EtBr+200 mg/L SP),high-dose EtBr(100μg/L),and high-dose EtBr with SP(100μg/L EtBr+200 mg/L SP);the exposure period was 2 weeks.Low and high doses of EtBr induced alterations in some hematological,biochemical,and histopathological parameters.Necrotic hepatocytes,degenerated area,vacuolated hepatocytes,pyknotic nuclei,constricted and dilated blood sinusoids,and infiltration of inflammatory cells were observed.Lipid peroxidation concentration was not significantly different in groups exposed to low doses of EtBr and EtBr with SP,but it was increased in groups exposed to high doses of EtBr and EtBr with SP,compared with the control group.After feeding with SP,most histological and histochemical parameters restored to normal values.Therefore,SP may possess the ability to preserve the structural integrity of the hepatic and renal membranes.展开更多
A two-factor(23)orthogonal testwas conducted to investigate the effects of dietary myo-inositol(MI)on the osmoregulation and carbohydrate metabolism of euryhaline fish tilapia(Oreochromis niloticus)under sustained hyp...A two-factor(23)orthogonal testwas conducted to investigate the effects of dietary myo-inositol(MI)on the osmoregulation and carbohydrate metabolism of euryhaline fish tilapia(Oreochromis niloticus)under sustained hypertonic stress(20 practical salinity units[psu]).6 diets containing either normal carbohydrate(NC,30%)or high carbohydrate(HC,45%)levels,with 3 levels(0,400 and 1,200 mg/kg diet)of MI,respectively,were fed to 540 fish under 20 psu for 8 weeks.Dietary MI supplementation significantly improved growth performance and crude protein content of whole fish,and decreased the content of crude lipid of whole fish(P<0.05).Curled,disordered gill lamella and cracked gill filament cartilage were observed in the gill of fish fed diets without MI supplementation.The ion transport capacity in gill was significantly improved in the 1,200 mg/kg MI supplementation groups compared with the 0 mg/kg MI groups(P<0.05).Moreover,the contents of Na^(+),K^(+),Cl^(-)in serum weremarkedly reduced with the dietary MI supplementation(P<0.05).The fish fed 1,200 mg/kg MI supplementation had the highest MI content in the gills and the lowest MI content in the serum(P<0.05).Additionally,the fish fed with 1,200 mg/kg MI supplementation had the highest MI synthesis capacity in gills and brain(P<0.05).Dietary MI markedly promoted the ability of carbohydrate metabolism in liver(P<0.05).Moreover,fish in the 1,200 mg/kg MI groups had the highest antioxidant capacity(P<0.05).This study indicated that high dietary carbohydrate would intensify stress,and impair the ability of osmoregulation in tilapia under a long-term hypersaline exposure.The supplementation of MI at 1,200 mg/kg in the high carbohydrate diet could promote carbohydrate utilization and improve the osmoregulation capacity of tilapia under long-term hypertonic stress.展开更多
This study was conducted to evaluate effects of dietary palm oil levels on growth performance,feed utilization,body composition and serum metabolites of Oreochromis niloticus.Five isonitrogenous diets,32% crude protei...This study was conducted to evaluate effects of dietary palm oil levels on growth performance,feed utilization,body composition and serum metabolites of Oreochromis niloticus.Five isonitrogenous diets,32% crude protein with increasing palm oil levels of 0(Control,CTRL),2%,4%,6% and 8% were used as the major lipid source for the trial.The results showed that greatest weight gain,specific growth rate,and protein efficiency ratio occurred at 6% dietary palm oil level.Dietary palm oil levels significantly(P<0.05)affected lipid,moisture,ash and crude protein contents in muscle and whole body.Serum triglycerides,cholesterol and total protein were significantly affected by elevated palm oil levels.Furthermore,total saturates,total n-3 poly unsaturated fatty acids(PUFA),total n-6 PUFA as well as DHA/EPA in muscle were significantly affected by different levels of palm oil.Fish fed the 6% palm oil level recorded the highest level of whole body docosahexaenoic acid(DHA),which was significantly higher than that of the control.The nutritional quality of O.niloticus was altered by different palm oil levels.The present study suggests that 6% dietary palm oil is the best feed formulation for tilapia,Oreochromis niloticus.展开更多
Mammalian T-cell responses require synergism between the first signal and co-stimulatory signal.However,whether and how dual signaling regulates the T-cell response in early vertebrates remains unknown.In the present ...Mammalian T-cell responses require synergism between the first signal and co-stimulatory signal.However,whether and how dual signaling regulates the T-cell response in early vertebrates remains unknown.In the present study,we discovered that the Nile tilapia(Oreochromis niloticus)encodes key components of the LAT signalosome,namely,LAT,ITK,GRB2,VAV1,SLP-76,GADS,and PLC-γ1.These components are evolutionarily conserved,and CD3εmAb-induced T-cell activation markedly increased their expression.Additionally,at least ITK,GRB2,and VAV1 were found to interact with LAT for signalosome formation.Downstream of the first signal,the NF-κB,MAPK/ERK,and PI3K-AKT pathways were activated upon CD3εmAb stimulation.Furthermore,treatment of lymphocytes with CD28 mAbs triggered the AKT-mTORC1 pathway downstream of the co-stimulatory signal.Combined CD3εand CD28 mAb stimulation enhanced ERK1/2 and S6 phosphorylation and elevated NFAT1,c-Fos,IL-2,CD122,and CD44 expression,thereby signifying T-cell activation.Moreover,rather than relying on the first or co-stimulatory signal alone,both signals were required for T-cell proliferation.Full T-cell activation was accompanied by marked apoptosis and cytotoxic responses.These findings suggest that tilapia relies on dual signaling to maintain an optimal T-cell response,providing a novel perspective for understanding the evolution of the adaptive immune system.展开更多
为了研究不同盐度下尼罗罗非鱼(Oreochromis niloticus)、萨罗罗非鱼(Sarotherodon melanotheron)和以色列红罗非鱼(Israel red tilapia)幼鱼生长的影响,试验选择尼罗罗非鱼、萨罗罗非鱼和以色列红罗非鱼幼苗各150尾。初始平均体重分别...为了研究不同盐度下尼罗罗非鱼(Oreochromis niloticus)、萨罗罗非鱼(Sarotherodon melanotheron)和以色列红罗非鱼(Israel red tilapia)幼鱼生长的影响,试验选择尼罗罗非鱼、萨罗罗非鱼和以色列红罗非鱼幼苗各150尾。初始平均体重分别为(2.74±0.12)g、(2.69±0.10)g和(2.75±0.11)g。试验共设置5个盐度水平,分别为0‰、10‰、20‰、30‰、40‰。每种鱼每个盐度30尾,并设置3个平行小组。试验为期60 d。结果显示,终末体重和日均增重量以M0(1)组的最高,其生长速度显著的高于其它处理小组(P<0.05)。除处理M10(1)组外,其它均达到极显著水平(P<0.01)。M0(2)、M10(2)、M40(1)和M40(3)的生长速度则显著的慢于其它各个处理小组,其中经过对比,生长速度最快和生长速度最慢相比相差了4倍。成活率和肥满度以M0(2)、M10(2)、M20(2)、M30(2)和M40(2)相对显著高于其它几个处理小组(P<0.05)。在不同盐度梯度下,对3种鱼进行饲养,其终末体重、日均增重、成活率和肥满系数指标均存在显著性差异(P<0.05),说明盐度和罗非鱼品种对罗非鱼的生长速度、成活率和肥满度均有显著影响。在5种盐度下,萨罗罗非鱼的成活率高于以色列红罗非鱼和尼罗罗非鱼,萨罗罗非鱼的肥满系数显著高于尼罗罗非鱼和以色列红罗非鱼,以色列红罗非鱼与尼罗罗非鱼的肥满系数没有显著差异。该研究发现,尼罗罗非鱼和以色列红罗非鱼在低盐度水中生长快,萨罗罗非鱼在高盐度水中生长快。展开更多
基金The financially supported by the Program of The National Youth Talent Support Program of China.
文摘In this study,chondroitin sulfate was extracted from Oreochromis niloticus bones(OCS)and isolated to three fractions(OCS-1,OCS-2,and OCS-3).The physicochemical properties and structure characterization including monosaccharide,disaccharide compositions,molecular weight(Mw)of OCS were determined by HPAEC,HPLC-SAX,HPGPC,FT-IR spectra,and 1D/2D NMR.Moreover,their thermal properties,crystalline structure,and microstructure were also analyzed.Results showed that their Mw were between 10 kDa and 50 kDa.CS-6 was the predominant disaccharide unit in four OCS,and the CS-4/CS-6 ratios were close to CS from shark cartilage.Besides,the results of antioxidant activity showed that different fractions of OCS had a distinct DPPH radical,hydroxyl radical,and ABTS+radical scavenging activity.OCS-1 has the highest scavenging activities in DPPH and hydroxyl radical compared with other fractions,which showed a higher medicinal value.Those findings may lay some theoretical basis for the potential application development of OCS.
文摘The optimization of aquaculture production requires the selection of efficient strains. Thus, genetic improvement has become one of the important levers to boost the development of aquaculture. The objective of this study was to carry out genetic characterization of Nile tilapia Oreochromis niloticus, one of the most cultivated fish species in Senegal, in order to select an efficient strain to optimize local fish production. Thus, fish from five different populations (Richard-Toll, ANA, ITACA, Mbodiene and Sauvage) were analyzed, with 15 individuals per population. Genetic diversity and population structure were assessed using molecular genetic analyses by sequence characterized amplified region (SCAR) and microsatellite (SSR) markers. The analyses of the SCARII marker were conducted on four populations (ANA, ITACA, Sauvage and Mbodiene) while microsatellite analyses were conducted on all five populations. The results show high levels of polymorphism of SSR markers, and a high level of observed heterozygosity (Ho), indicating a high within-population genetic variability. These results are in agreement with the AMOVA results, which indicated a high within-population genetic variability (94%). The genetic structure analysis by DAPC indicates that the five populations analyzed are structured into four groups, which are highly heterogeneous because they share common allele individuals. The analysis of the genetic structure by AMOVA showed a low degree of differentiation between the populations (6%), in agreement with the genetic differentiation index (Fst = 0.059). The heterogeneity of studied populations implies a genetic flow over time, which may have existed between the original populations. The overall negative Tajima D values and low genetic differentiation indicate an excess of rare mutations in the populations studied, resulting from a recent population expansion from a limited number of initial breeders isolated in locale hatcheries. Thus, further studies with a much larger panel of markers are required to better differentiate the strains and identify the most efficient ones for sustainable local aquaculture production.
文摘This study was carried out in 2022 at the Itato agriculture community estate of fish hatchery in eastern Senegal with the aim of finding an alternative method to 17-α-methyl testosterone (MT) by using Garcinia kola “Bitter kola” powder to obtain Oreochromis niloticus male sex populations. 1800 fry of average size between 0.01 and 0.02 g were distributed in 12 aboveground tanks of 1 m3 each at a rate of 150 individuals/tank, following 6 duplicate treatments. The negative (B1 and B2) and positive (B3 and B4) control diets, to which between 0 and 60 mg/kg of 17alpha-methyl testosterone had been added respectively, were mixed with industrial feed containing 40% protein;the tank diets (B5 and B6), (B7 and B8), (B9 and B10) and (B11 and B12) contained 10 g, 20 g, 30 g and 40 g of Garcinia kola powder respectively for 1 kg of industrial feed con-taining 40% protein. These different treatments resulted in high proportions of males in the order of 97.03%;98.09% for the hormone and proportions of 94.03%;93.26% for 20 g of Garcinia kola extracts. In terms of weight growth, the best average weights for the hormone and Garcinia kola were 0.896 g and 0.980 g respectively. With regard to fish survival, the following results were recorded: 95.53% and 94.56% respectively for additions of 20 g and 30 g of Garcinia kola extracts to the feed supplied to the fish. On the other hand, a significant difference in the mortality rate of 35% and 5% respectively for the conventional hormone and 20 g of Garcinia kola extracts was observed. To conclude the study, it is recommended that further studies be carried out to determine the quality of the flesh, their life stages and the profile of the amino acids present in their proteins.
文摘Dried fish are susceptible to bacteria and fungi attack and are liable to chemical changes which cause losses in quality and reduction of shelf-life. It is important therefore to maintain the quality of fish because continuous consumption of contaminated fish and their products may predispose consumers to health hazards. Maintenance of high quality fish therefore calls for adequate and effective preservation techniques. The study examined the effectiveness of essential oils of Ocimum basilicum and Ocimum gratissimum from two Agro-ecological zones of Cameroon in limiting the microbial proliferation and preserving the quality of smoke-dried Oreochromis niloticus fish stored at 25˚C for two months. The plant materials were harvested from the Western Highlands and Monomodal Humid Forest agroecological zones of Cameroon. Extraction of the essential oil from the plants was done by hydro-distillation. The fish species (Oreochromis niloticus) used in this study was chosen based on a survey study on the most consumed species of freshwater smoke-dried fish in the Western Highlands and Monomodal Humid Forest Agro-ecological zones of Cameroon. Heterotrophic bacteria counts, fungi counts and Enterobacteriaceae counts were used to assess the level heterotrophic bacteria, fungi and Enterobacteriaceae respectively in the fish samples during storage and were done by culture techniques using total plate count agar, potato dextrose agar and violet red bile glucose agar respectively. Total volatile basic nitrogen, peroxide value, and thiobarbituric acid reactive substance assays were used as spoilage indices to assess the nutritional quality of the fish during storage. From the survey study, Oreochromis niloticus was the most consumed smoke-dried fish in the Western Highlands (35.45%) and Monomodal Humid Forest (34.55%) agroecological zones. All the EOs caused a significant reduction in the microbial loads, total volatile basic nitrogen, peroxide value, and thiobarbituric acid reactive substance of smoke-dried Oreochromis niloticus as storage progressed. However, the reduction in these values was more pronounced in samples treated with essential oils of O. gratissimum from the Western Highlands, with heterotrophic bacteria, fungi and Enterobacteriaceae counts being 5.89, 6.97 and 4.59 log<sub>10</sub> cfu/g respectively at the end of the storage period. This was followed by essential oils of O. gratissimum from the Monomodal Humid Forest with heterotrophic bacteria, fungi and Enterobacteriaceae counts being 6.11, 7.79 and 4.86 log<sub>10</sub> cfu/g respectively at the end of the storage period. Also, essential oils of O. gratissimum from the Western Highlands was more effective in preserving the fish quality as lowest total volatile basic nitrogen (12.29 mg/100g), peroxide value (2.79 mEq O<sub>2</sub>·Kg<sup>−1</sup>) and thiobabituric reactive substance (1.695 mg MDA/Kg) values were observed for fish samples treated with this extract at the end of the storage period. This was followed by essential oils of O. gratissimum from the Monomodal Humid Forest with total volatile basic nitrogen (14.95 mgN/100g), Peroxide value (3.23 mEq O<sub>2</sub>·Kg<sup>−1</sup>) and thiobabituric reactive substance (2.354 mg MDA/Kg) at the end of the storage period. From the results obtained, essential oils from O. gratissimum were more effective than that from O. basilicum in the two agroecological zones and should be considered as natural alternative to chemical preservatives for further application in food preservation.
文摘Irrigation of fish farms with agricultural drainage water may affect cultured fish species. So, the present study utilizes antioxidants supplemented diet to overcome deterioration of drainage water and its negative effect on fish. The studied groups are fish cultured in dechlorinated tap water as control group or drainage water and fed commercial basal diet. While, the other studied groups represented by Oreochromis niloticus fish cultured in drainage water and fed either commercial diet supplemented with vitamin C (5 g/kg diet) or fennel (5 g/kg diet) for 12 weeks. Results of the water physico-chemical parameters of all studied treatments revealed deterioration of the drainage water with a decrease in dissolved oxygen and an increase in pH, total hardness, total alkalinity, salinity, ammonia, nitrite and heavy metals (Cu, Pb and Cd) with significant differences (P ≤ 0.01) in comparison to that of the control dechlorinated tap water group. Data clarified also that Oreochromis niloticus cultured in drainage water showed a decrease in growth rate accompanied by deterioration of fish meat quality. However, fish reared in the same drainage water for the same exposure period and fed vitamin C or fennel supplemented basal diet (5 g/kg diet) recorded values of the studied parameters more or less similar to that of control group fish. Data of the present study, empowered aquaculturist to supplement fish rations with fennel or vitamin C as antioxidants to improve fish growth rate, meat quality as well as protect fish against heavy metals toxicity that could threat Human Being.
基金Supported by China Agriculture Research System(CARS-49)Fujian Seed Industry Innovation and Industrialization(2011FJZY)
文摘Through PCR amplification, 5' flanking region and partial open reading frame(ORF) of gene of Nile tilapia(Oreochromis niloticus) was cloned by PCR amplification. Sequence analysis showed that no difference was found in known functional regions. This study was to construct and identify the mammalian expression vector of pEGFP-β-actin and to detect whether it could express in HEK 293T cell line. pEGFP-β-actin was transfected into HEK 293T cells with Lipofectamine 2000. The results showed that correct construction of recombinant pEGFP-β-actin has been shown by restriction enzyme digestion. The expression of gene in HEK 293T cells could be observed under microfluoroscope. pEGFP-β-actin could repress EGFP protein in HEK 293T cells. The results showed that β-actin gene promoter possessed effective transcription activities in eukaryotic cells. The work laid foundations for further study on the gene engineering and autotransgenic tilapia.
基金The authors would like to acknowledge NACOSTI(National Council Science Technology&Innovation),for providing research fundsthe Director of KMFRI(Kenya Marine and Fisheries Research Institute)for logistical support,and colleagues from KMFRI technical staff(J.Ouko,R.Mairura,and Z.Awuondo).We also wish to thank the technical staff of UoN(University of Nairobi),Chiromo Laboratories,for instrumental data handling and analysis.
文摘Concentrations of OCP(Organochlorine Pesticide)residues were determined in cultured Nile tilapia(Oreochromis niloticus)fish in target stations within 1st order wetland of River Kuja,Kenya,between February-November,2017.The aim was to assess the residue levels in wild and pond cultured fish within a heavily populated agricultural area of South Western Kenya.Biota samples were analysed for selected HCHs(Hexachlorocyclohexane)isomers,DDT(Dichlorodiphenyltrichloroethane)and metabolites and cyclodienes pesticide residues using GC-ECD(Gas Chromatography Equipped with Electron Capture Detector).Most of OCPs observed were BDL(Below Detection Limit)to detectable levels.Larger percentages(>50%)of DDTs and HCHs were BDL and exhibited consistency,with significant(p<0.05)differences in mean contamination levels in fish within the wetland,with average muscle tissue pesticides concentrate ranging between 0.229-2.541mg/kg for Nile tilapia.Most dominant isomer in target species was Lindane(g-HCH)(3.417±0.983mg/kg)and Endosulfans.Mean Endosulfan sulfate was 2.499±0.071mg/kg d.w.and most frequently detected,and Methoxychlor(2.235±1.459mg/kg),respectively.Mean Aldrin and Dieldrin was 2.028 and 0.574mg/kg d.w.Concentration for DDT and its metabolites was 0.27-3.71mg/kg for p,p’-DDE(DichlorodiphenylDichloroEthene),BDL-1.098 for p,p’-DDD(DichloroDiphenylDichloroEthane),and 0.105-3.518mg/kg for p,p’-DDT with significant differences in mean values and ranges whose levels were below the WHO(World Health Organization)maximum acceptable thresholds of 0.2,2,20 and 5.0mg/kg in fish and sea food.Interventions and monitoring need up-scaling in minimizing public health risks posed by consumption and exposure.
文摘This study was designed to investigate the possible variation in bioaccumulation of heavy metals (lead, cadmium, zinc, cobalt, chromium, nickel, and manganese) in the tissue of harvested Oreochromis niloticus (tilapia) and the associated fungi from vials treated with soil from e-waste dumpsite and soil without e-waste. E-waste is electronic waste which contains valuable metals as well as potential environmental contaminants. The heavy metals in soil and fish samples were determined using flame atomic absorption spectrophotometer (AAS) after homogeneity and digestion of samples. The associated fungi were identified using standard microbiological methods. The genera of the associated fungi were: Penicillium, Candida, Articulospora, Aspergillus, Aspergillus, Aspergillus, Rhizopus, Mucor, Zoopage, Varicosporium and Rhodoturula. The quantity of fungi isolated from each pollution treatments showed that the number of fungi were inversely proportional to the quantity of e-waste soil pollution and directly proportional to the quantity of soil without e-waste pollution. The occurrence of the fungi species revealed that the untreated (control) vial had the highest occurrence (191) while the lowest occurrence (103) occurred in the vial polluted with the highest quantity of soil from e-waste dumpsite. The pH and the biochemical oxygen demand (BOD) of the vials were significantly affected by the pollutions. Variations were also observed in the bioaccumulation of the heavy metals by Oreochromis niloticus. Cadmium (0.01 mg/kg) and nickel (0.02 - 0.08 mg/kg) were the least recorded metal in the tissue of the fish while cobalt was not detected after the five weeks period. The sequence of the heavy metals concentrations in Oreochromis niloticus tissue samples was Zn > Mn > Pb > Cr > Ni > Cd > Co. The accumulation of the metals in the fish tissue were, however, lower than the international maximum guidelines, except for manganese (0.29 - 3.13 mg/kg) that exceeded the 0.01 - 0.05 mg/kg threshold levels for manganese by Federal Environmental Protection Agency (FEPA). Protecting the environments from toxic metals is necessary, hence a need for public awareness on the dangers of these toxic metals and law for proper disposal of e-waste.
基金Financial support was provided by the Division de Ciencias Biologicas y de la Salud,UAM-Iztapalapa.
文摘We present results of a long-term study aimed to optimize Nile tilapia O. niloticus production in a recirculating aquaculture system (RAS) in México City. Three experiments were evaluated: 1) fry production;2) production of masculinized fries;and 3) assessment of growth under three different densities (10, 30 and 75 fish/m3). The broodstock produced on average 2400 ± 600 fry every 15 days during six months, with a total production of 28,800 ± 2000. One hundred percent males were produced in 274-L raceways in an eight-week period. The obtained results in fish production in the RAS system indicated variations related to density. A daily growth rate of 3.6 g/day was registered with a density of 10 fish/m3, 0.9 g/day in 30 fish/m3 and 0.4 g/day in 75 fish/m3. This information could be useful for production purposes in this type of systems.
基金thank CAPES for the award of scholarship to the auhor
文摘Since amateur fishing in fishponds has been on the increase in Brazil, there is a great concern on the microbiological quality of fish. One hundred and thirty-eight samples were collected during the dry and rainy periods in ten fish farms. Aeromonas spp. counts and tests for sensitiveness to antimicrobials were performed, coupled to the physical and chemical analyses of water. Tests revealed that 70% of samples were contaminated by Aeromonas spp., with water averaging 2.92 Log CFU/100 mL during the rainy period and 3.16 Log CFU/100 mL during the dry one. Fish contaminated by Aeromonas spp. averaged 2.58 Log CFU/100 mL during the rainy period and 3.53 Log CFU/100 mL during the dry one. Aeromonas spp. samples were multi-resistant to 2 or 8 antimicrobials in 62.5% of the samples. Ampicillin was the antimicrobial with the highest resistance percentage rate. Results showed that fish bred in amateur fish farms constituted a health risk for the population.
文摘Ethidium bromide(EtBr)is one of the contaminants recorded in aquatic environments whose effects have been investigated;however,there is still limited knowledge about its remediation.This study examined the potential protective effects of Spirulina platensis(SP)against the effects of EtBr toxicity in the Nile tilapia(Oreochromis niloticus)fry.Fry were divided to five groups,viz.,a control and four treatment groups of low-dose EtBr(10μg/L),low-dose EtBr with SP(10μg/L EtBr+200 mg/L SP),high-dose EtBr(100μg/L),and high-dose EtBr with SP(100μg/L EtBr+200 mg/L SP);the exposure period was 2 weeks.Low and high doses of EtBr induced alterations in some hematological,biochemical,and histopathological parameters.Necrotic hepatocytes,degenerated area,vacuolated hepatocytes,pyknotic nuclei,constricted and dilated blood sinusoids,and infiltration of inflammatory cells were observed.Lipid peroxidation concentration was not significantly different in groups exposed to low doses of EtBr and EtBr with SP,but it was increased in groups exposed to high doses of EtBr and EtBr with SP,compared with the control group.After feeding with SP,most histological and histochemical parameters restored to normal values.Therefore,SP may possess the ability to preserve the structural integrity of the hepatic and renal membranes.
基金grants from the National Natural Science Foundation of China(No.32172946)China Postdoctoral Science Foundation(2018 M630418)the Fundamental Research Funds for the Central Universities,ECNU and China Agriculture Research System-46(CARS-46).
文摘A two-factor(23)orthogonal testwas conducted to investigate the effects of dietary myo-inositol(MI)on the osmoregulation and carbohydrate metabolism of euryhaline fish tilapia(Oreochromis niloticus)under sustained hypertonic stress(20 practical salinity units[psu]).6 diets containing either normal carbohydrate(NC,30%)or high carbohydrate(HC,45%)levels,with 3 levels(0,400 and 1,200 mg/kg diet)of MI,respectively,were fed to 540 fish under 20 psu for 8 weeks.Dietary MI supplementation significantly improved growth performance and crude protein content of whole fish,and decreased the content of crude lipid of whole fish(P<0.05).Curled,disordered gill lamella and cracked gill filament cartilage were observed in the gill of fish fed diets without MI supplementation.The ion transport capacity in gill was significantly improved in the 1,200 mg/kg MI supplementation groups compared with the 0 mg/kg MI groups(P<0.05).Moreover,the contents of Na^(+),K^(+),Cl^(-)in serum weremarkedly reduced with the dietary MI supplementation(P<0.05).The fish fed 1,200 mg/kg MI supplementation had the highest MI content in the gills and the lowest MI content in the serum(P<0.05).Additionally,the fish fed with 1,200 mg/kg MI supplementation had the highest MI synthesis capacity in gills and brain(P<0.05).Dietary MI markedly promoted the ability of carbohydrate metabolism in liver(P<0.05).Moreover,fish in the 1,200 mg/kg MI groups had the highest antioxidant capacity(P<0.05).This study indicated that high dietary carbohydrate would intensify stress,and impair the ability of osmoregulation in tilapia under a long-term hypersaline exposure.The supplementation of MI at 1,200 mg/kg in the high carbohydrate diet could promote carbohydrate utilization and improve the osmoregulation capacity of tilapia under long-term hypertonic stress.
基金This work was financially supported by the China Agriculture Research System(CARS-49)Shanghai Collaborate Innovation Center for Aquatic Animal Genetics and Breeding(ZF1206)to J.Zhao.
文摘This study was conducted to evaluate effects of dietary palm oil levels on growth performance,feed utilization,body composition and serum metabolites of Oreochromis niloticus.Five isonitrogenous diets,32% crude protein with increasing palm oil levels of 0(Control,CTRL),2%,4%,6% and 8% were used as the major lipid source for the trial.The results showed that greatest weight gain,specific growth rate,and protein efficiency ratio occurred at 6% dietary palm oil level.Dietary palm oil levels significantly(P<0.05)affected lipid,moisture,ash and crude protein contents in muscle and whole body.Serum triglycerides,cholesterol and total protein were significantly affected by elevated palm oil levels.Furthermore,total saturates,total n-3 poly unsaturated fatty acids(PUFA),total n-6 PUFA as well as DHA/EPA in muscle were significantly affected by different levels of palm oil.Fish fed the 6% palm oil level recorded the highest level of whole body docosahexaenoic acid(DHA),which was significantly higher than that of the control.The nutritional quality of O.niloticus was altered by different palm oil levels.The present study suggests that 6% dietary palm oil is the best feed formulation for tilapia,Oreochromis niloticus.
基金supported by the National Key Research and Development Program(2022YFD2400804)National Natural Science Foundation of China(32022086,31972822)Natural Science Foundation of Shanghai(20ZR1417500)。
文摘Mammalian T-cell responses require synergism between the first signal and co-stimulatory signal.However,whether and how dual signaling regulates the T-cell response in early vertebrates remains unknown.In the present study,we discovered that the Nile tilapia(Oreochromis niloticus)encodes key components of the LAT signalosome,namely,LAT,ITK,GRB2,VAV1,SLP-76,GADS,and PLC-γ1.These components are evolutionarily conserved,and CD3εmAb-induced T-cell activation markedly increased their expression.Additionally,at least ITK,GRB2,and VAV1 were found to interact with LAT for signalosome formation.Downstream of the first signal,the NF-κB,MAPK/ERK,and PI3K-AKT pathways were activated upon CD3εmAb stimulation.Furthermore,treatment of lymphocytes with CD28 mAbs triggered the AKT-mTORC1 pathway downstream of the co-stimulatory signal.Combined CD3εand CD28 mAb stimulation enhanced ERK1/2 and S6 phosphorylation and elevated NFAT1,c-Fos,IL-2,CD122,and CD44 expression,thereby signifying T-cell activation.Moreover,rather than relying on the first or co-stimulatory signal alone,both signals were required for T-cell proliferation.Full T-cell activation was accompanied by marked apoptosis and cytotoxic responses.These findings suggest that tilapia relies on dual signaling to maintain an optimal T-cell response,providing a novel perspective for understanding the evolution of the adaptive immune system.
