In this study, the defatted rice bran (DRB) was hydrolysed by dilute H2SO4 solution to obtain sugar solution for culturing Yarrowia lipolytica Po1g. In hydrolysis process, some important factors affecting to sugar concentration such as H2SO4 concentration (from 2% to 5%), reaction time (from 2 h to 8 h), temperature (from 60°C to 90°C) and ratio of defatted rice bran to acid solution (from 1/4 g/mL to 1/12 g/mL) were investigated. The results showed that 4% of H2SO4, 6 hrs, 90°C and the ratio of 1/8 g/mL were good reaction conditions for hydrolysing the defatted rice bran and concentration of total sugar in the defatted rice bran hydrolysate (DRBH) was 53.59 g/L. The DRBH was detoxified with Ca(OH)2 before using for culturing yeast. In culturing process, some factors affecting growth and lipid accumulation of the yeast such as time, sugar concentration, nitrogen source, pH, and carbon source were conducted. The result showed that the maximum of yeast concentration was 11.73 g/L with 25.41% of lipid content when the yeast was cultured 4 days in detoxified DRBH with sugar concentration of 30 g/L, without adding nitrogen source. Composition of lipid consisted high free fatty acid (FFA) 82.53% and glycerides such as monoacylglyceride (11.45%), diacylglyceride (1.41%), and triacylglyceride (3.05%). The fatty acid profile was varying from C16 to C18 and this was considered as potential biodiesel feedstock.

Currently, overusing agro-chemicals on agricultural plants affects consumer health. The urgent issue, so, is to have a high-tech solution to remove the chemical residue in post-harvest agricultural products. Thus, designing ultrasonic washing tanks used to clean agricultural products out of chemical residues would be a research contributing to save consumer’s health from food poisoning. The tank was designed to allow adjusting transmission frequency and intensity of ultrasonic waves suitable to different agro-products and the primary experiment results indicated that using the designed ultrasonic tank is effective in reducing a kind of insecticide residue from some vegetables.

Nowadays, the Multiple Criteria Decision Making using Linear Programming (MCDMLP) have been becoming popular in land-use planning. However, these applications of this method still have some difficulty because of the majority solver software are designed for general purpose, thus the land use planers need more programming skills to implement solving models. This study is aimed to build a specific linear programming application named LandOptimizer for agricultural land use optimizing based on social-economic and environmental factors. The application was built with Visual Basic.Net programming language and was based on the open source library LPSolve 5.5.2.5 for MCDM LP solving. This resource was able to help the non-propramming users for land management field especially. For verifying the application, an optimization of agricultural land use of Co Do district, Can Tho city have been launch on both LandOptimizer and the GAMS platform, the solved results using of LandOptimizer and GAMS platform were showed correspondingly.

The survey was carried out at a Wastewater Treatment Enterprise in Binh Duong province in December 2014, March and May 2015. The objective is to identify the zooplankton composition and diversity at the enterprise and natural waterbodies nearby. There are 4 sample points, 2 in the enterprise (1 in treated wastewater tank and 1 in waste stabilization pond) and 2 in the river area near the enterprise (belong to Sai Gon river). One hundred and twenty-eight species were identified belong to fifty - two genera and 5 groups (Protozoa, Rotatoria, Cladocera, Copepoda, Ostracoda). Releasing the zooplankton community from the enterprise may cause a serious change in the zooplankton community in the river.

This research was conducted in the Tra Noc Industrial Zone, Can Tho city to assess the current status of exploitation, groundwater head changes and management of groundwater resources (GWR). The relationship between groundwater extraction, water level in Hau River (CTH-039803 station) and groundwater levels at monitoring stations was established. The results show that the extraction of groundwater in the Tra Noc Industrial Zone is very large; total exploitation amount has increased six times, from 3,568 m3/day to 19,738 m3/day, respectively, from 2004 to 2010. Over-exploitation of GWR may be a major cause of decrease in groundwater levels leading to the decrease in groundwater level of Pleistocen and Holocen aquifers of 4m and 1m, respectively from 2000 to 2015. Rainfall and Hau river is found to be the major source of recharge to Holocen aquifer. Besides, management of GWR is not effective, lack of close coordination between enterprises and local GWR management agencies/departments. Therefore, more effective management of GWR is urgently needed in the current and in the future.

The objective of this study is to evaluate the involvement of community in decision-making process of hydropower projects with a case study in the Srepok River Basin, Dak Lak province (Srepok 3, 4 and 4A). Firstly, relevant secondary data and information from key informant were collected and analyzed. Then, 80 households were interviewed and group discussions were carried out at three communes. The results were then analyzed and feedback was obtained from stakeholders. Results showed that in the 80 households interviewed, 29% are the poor, Kinh and Muong are dominant. Land acquisition, compensation, resettlement, and relocation stage is important step in decision-making process due to directly related to affected communities. District authority and investors are found to have a strong influence on the decision-making compared to the other authorities. Meanwhile affected people, mass unions, research agencies have almost no role. Besides the benefit brought to socio- economic development, hydropower projects have also caused many problems during the project cycle as the voice of affected communities is very low or not considered.

This study is aimed to assess the efficiency of residential wastewater treatment by membrane bioreactor (MBR) technology. The working volume of the reactor is 36 liters (L*W*H = 24*20*75 cm) and the pore size of submerged membrane modules is 0.4 μm. MBR experimental model is a combination of the organic matter biodegradation and microbial biomass separation technique by membranes. Laboratory scale-model was set up to assess the efficiency of residential wastewater removal in the period of 121 days with the organic loading rates from 1.7 to 6.8 kgCOD/m3.day. Due to the high biomass concentration, the wastewater treatment efficiency of MBR is higher than traditional methods. The average treatment efficiency of TSS, BOD5, COD, TN, TP are 89.4; 94.6; 92.6; 64.6 and 79.2%, respectively. In general, membrane filtration technology can be applied to treat high organic loading wastewater, this is an effective solution for sustainable environmental protection.

The study analysed the current application and determining important issues constraining the development of the new-techniques of rice farming systems (NTRFs) in the Vietnamese Mekong Delta (VMD) by using the DPSIR model (Driving forces, Pressures, State, Impacts, and Response) and SWOT frameworkd. The results showed that the new techquices of rice cultivation were widely applied in the study area occupying of 70–80% farmers; however, there were still limitations on the combination of improved farming techniques. Besides the constraints such as uneven field surface and water resource change, it is found that the important issues constraints for the development of the NTRFs models including awareness of local farmers on water shortage and water-saving irrigation, and lack of investment to innovate the expansion of the new technologies of rice cultivation in the study area. The approciate solution to solve the problems is improving the knowledge of famers and innovation in local government management by inviting local young intellectuals to new-techniques agricultural production.

Saline intrusion has greatly expanded in the Vietnamese Mekong Delta in the recent years causing negative impacts on agriculture in coastal areas and leading to challenges for water resources management. This study was conducted to evaluate the effectiveness of surface water and groundwater resources management for agriculture cultivation in early 2016 in the Long Phu district, Soc Trang province. Descriptive statistic and individual interview (with farmers and managers) approaches were applied in this study. The obtained results showed that saline intrusion caused difficulties for distributing water resources, especially insufficient freshwater supply for the 3rd (Spring – Summer) rice crop in early 2016. In addition, the prolonged drought led to the increase of water demands for rice cultivation. Regarding to the water resources management, the groundwater exploitation was well-managed. Besides, there were no conflicts between famers in using surface water for rice cultivation. However, due to certain limitations in interaction between the local residents and the government (district and communes), the local regulations were not sufficiently applied.

Xylene is a monoaromatic hydrocarbon which is widely used as solvent in laboratories. The compound is used as solvent in leather, rubber, printing industries as well as one of the major components of gasoline. Due to its water solubility, xylene is considered a contaminant in water reservoirs, especially groundwater, posing risk for human health. Sixteen bacterial isolates grown in minimal medium supplemented with xylene as the only carbon source were isolated from sediment samples in the sedimentation chamber of the wastewater treatment system of College of Natural Sciences, Can Tho University. Among these isolates, strains XL3.1, XL6.2 and XL22.1 were able to degrade more than 95% xylene (0.125% v/v) after 24 hours of incubation. Strain XL6.2 was the best xylene degrader (97.81%) and was genetically identified as Rhodococcus sp. XL6.2.

Treating catfish fat based methyl esters with diethanolamine at elevated temperature has led to the formation of a mixture of N,N-bis(hydroxyethyl)carboxamide (44.31 %), exccess of methyl esters (28.38 %) and diethanolamine (22.13 %) and undetermined components (5.18 %). This mixture was then used as materials for production of emulsifiable concentrate (EC) formulation with abamectin and α-cypermethrin as active ingredients. In addition, catfish fat based methyl esters were used to partly substitute for xylene as solvent in the formulations. The prepared EC formulations meet all required standards according to TCVN 9475:2012 for abamectin and TCVN 8752:2014 for α-cypermerthrin. These EC formuations showed as good activity as the commercial abamectin- and α-cypermethrin-containing EC insecticide formulations against Rice leaf folder (Cnaphalocrosis medinalis G).

ZnO and GaN are the typical semiconductor materials. These materials were used in application for optoelectronic devices. Both ZnO and GaN have crystal structure wurtzite-like and they have many similar physical properties. Therefore, their combination into superlattice is expected to create a new material system with new physical properties. In this study, we investigate the electronic properties of the superlattice based on ZnO/GaN armchair nanoribbons by the density functional theory (DFT) method. We have used the PBE functional for GGA and a plane-wave basis set with the projector augmented wave method as implemented in the Vienna ab initio simulation package (VASP). In results, it is shown that the electronic structures of some crystal structures exist the strong quantum confinement effect.

A rapid and effective HPLC method with UV-Vis detector is described for the assay of cetirizine in tablet formulation. The determination was performed with a Gemini-NX C18 column (15 cm x 4,6 mm, 5 mm) and UV detection at 230 nm. The elution was achieved isocratically with a mobile phase of KH2PO4 (pH 7) - acetonitrile (58:42, v/v). The method was validated for specificity, linearity, accuracy, precision, limit of detection and limit of quantitation. The validated method was successfully used for quantitative analysis of three commercial tablets.

The main aim of this paper is to study the model of random walk with state space ℤ. The method of moments is here used, as in Depauw et al.’s paper (2009), to prove that this random walk converges in probability to a constant (Theorem 1.2) and give its rate also (Theorem 3.1). More precisely, with  be the corresponding Markov operator of the previous random walk and a given function f, we solve the Poisson equation and then treat the limits of its solutions, the rate of the convergence is instantly given by the convergence of the moment of random walk.

The replacement of the gravity anomaly in the Stokes and Vening-Meinesz equations by the set of gravity anomalies measured on the surface of the earth or in space leads to errors. These errors are evident when calculating the height anomaly and determining the angular deflection angle components. The purpose of this paper is to show the relationship between the quantity of errors to the discrete level of the original data. By using the gravitational field covariance density analysis method, the formula for estimating gravity anomaly is given, depending on the discreteness of the data and the gravity field's complexity.

This study was aimed to evaluate antibacterial and antioxidant activities of the methanol, hexane and ethyl acetate extracts from Pouzolzia zeylanica L. leaves and stems (fresh and dry). The antimicrobial activity was determined in the extracts using Kirby-Bauer method and the antioxidant activities using 2,2-diphenyl-1-picrylhydrazyl radical (DPPH). The studied antibiotics showed that all extracts have antimicrobial effect against three bacterial strains including E. coli, P. aeruginosa, S. aureus higher than positive control (with amoxicillin) at all studied levels with 40 µg/mL

Porcine epidemic diarrhea virus (PEDV) is a Coronavirus that caused an enteric infectious disease with high death rate for piglets particularly newborn. A survey on PEDV infection in sows was carried out in Tien Giang province. Blood samples from unvaccinated PED sows were collected. Antibodies against PEDV was determined by ELISA test with Porcine epidemic diarrhea virus antibody test kit, SwinecheckR PED indirect - Biovet – Canada. Results showed that a PEDV prevalence of sows was 33.72%. The highest prevalence was found in Cho Gao district (59.22%), then in Cai Lay (27.66%), Cai Be (14.52%) and lowest rate was in Chau Thanh district (10.20%). The highest PED antibody positive rate was found in the herd of the size from over 50 sows (34.95%). These rates for the herd size of 20-50 sows and under 20 sows were 33.66%, and 31.58% respectively. The positive rate of the sows that have given 4-5 litters and over 5 litters were 56.67% and 38.59% respectively. While these rates for sows given 2 and 3 litters were 33.33% and 27.5% respectively. Analysing the risk factors to PED suspected epidemic showed that, the highest risk factor was not disinfectant housing or disinfecting fewer than one time per every 2 weeks. The others were without disinfectant pits in the house; near distance to the disease outbreaking farm.

The different ultrasound - assisted extractions with ethanol 70% and methanol 70% from leaves and rhizomes of Imperata cylindrica revealed the presence of phenolics and tannins, flavonoids, quinones, coumarins, alkaloids, terpenoids and saponins. The leaf of I. cylindrica was extracted in methanol (LM70S) showed the highest total phenolic concentration was 73.45 to 86.90 gallic acid equivalents g-1 of extract. The highest total flavonoid content was revealed in ethanolic leaf extract (LE70S) (78.38 mg quercetin equivalent g-1 of extract), LE70S also demonstrated highest antioxidant actitvity with a lowest IC50 value (313.76±2.08 µg/ml) in comparison with those of the other extracts, the IC50 value of the standard ascorbic acid is 274.33±3.83 µg/ml. The methanolic leaf extract (LM70S) had the highest antibacterial activity with largest zones of inhibition of 9.6±0.14 mm against Escherichia coli and 8.4±0.14 mm against Bacillus subtilis at concentration 100 mg/mL. The I. cylindrica can be regarded as promising candidates for natural plant soures of antioxidant and antibacterial activities.

This study is aimed at evaluating effects of carrier materials on survival and biological activities of Bacillus aerophilus against Xanthomonasoryzae pv. oryzae (Xoo) causing rice bacterial leaf blight. Five carrier materials, i.e., talc, rice bran, rice kernel powder, rice grain powder and rice husk powder were used to prepare different B. aerophilus formulations at an initial cell concentration of 2×108 CFU/mL. Talc, rice bran and rice husk formulations maintained the number of viable B. aerophilus cells higher than 106 CFU per gram formulation as well as its antagonistic effects against Xoo after six months of storage. Under greenhouse conditions where rice plants were inoculated at 45 days after sowing, seed soaked with these three formulations after six months of storage effectively reduced lesion lengths until 15 days after inoculation compared to the untreated control. Thus, talc, rice bran and rice husk powder show their potentials for production of bio-products to control bacterial leaf blight in rice fields.

Tuber rot (“thối đồng tiền” in Vietnamese) is currently present in sweet potato fields of Bình Tân, Vĩnh Long of Vietnam. The aim of this study is to identify the pathogen which will serve as a basis to find effective control methods for the disease. A total of 32 bacterial isolates were obtained from 18 diseased samples. These samples were collected from 3 major sweet potato cultivation communes of Bình Tân, Vĩnh Long, i.e. Thành Đông, Thành Trung and Tân Thành. Using the Koch’s postulates, five isolates including BT5, BT14, BT15, BT19 and BT30 showed typical symptoms of the disease as observed under field conditions. Indeed, the yellowish brown lesions were observed which were circular, hollow and necrotic. The pathogen was identified as Klebsiella variicola through its morphological and biochemical characteristics combined with sequencing of the 16S rRNA and rpoB genes. Analyses of the sequences of these genes helped distinguish the bacterium from other Klebsiella sp.

The main objective of this study was to evaluate the efficacy of spent coffee grounds as carrier material to immobilize propoxur degrading bacteria strain, Paracoccus sp. P23-7 on degradation of propoxur in soil collected from shallot cultivation soil in Vinh Chau, Soc Trang province. Wood biochar and spent coffee grounds were used as two carrier materials to compare their function on immobilization and degradation capacity of propoxur in soil. Cow manure, azolla, milled eggshell and domestic charcoal were materials used to amend into the soil. Soil bacterial and fungal numbers and remained concentration of propoxur in soil were determined at day 0, 1, 3, 5, 7 and 11 of the experiment. The results showed that degradation of propoxur in soil by Paracoccus sp. P23-7 was more effective when this bacterial strain was immobilized in spent coffee grounds than in wooden biochar. The treatment amended with 1% milled eggshells (w/w) or 1% biomixture including cow manure, azolla, milled eggshell and domestic charcoal had higher propoxur degradation than other treatments. The results allowed us to conclude that spent coffee grounds could be reutilized as carrier material to immobilize Paracoccus sp. P23-7 strain to enhance the degradation of propoxur in soil and degradation result would be even much better if the soil was amended with either 1% milled eggshells or 1% biomixture. These materials can be used as soil amender or soil conditioner to accelerate the efficacy of bioremediation technology in cleaning up the contaminated soil.

Citripestis sagittiferella is a newly serious insect pest which is damaging citrus fruits in the Mekong delta of Vietnam. In order to establish basic information for integrated pest management, its damage status and major morphological and biological characteristics had been studied by farmers’ interviews and field and laboratory investigations, researches in laboratory and field condition. There were 14 insects and one mite species attacked Nam Roi pomelo trees, in which C. sagittiferella, Phyllocnistis citrella, Prays endocarpa, and Bactrocera dorsalis appeared with frequency of appearance >50%. Ratios of infected pomelo fruits varied from 2.28% - 3.63%, in which damage ratio of fruits at 5 - 10 cm diameter was 3.52% while these ratios of fruits at 10 cm diameter were 1.95% and 2.96%, respectively. In laboratory condition, a life cycle of C. sagittiferella was averagely 29.54 days with four stages including egg stage (4.09 days), 5 instar larval stage (13.44 days), pupal stage (10.13 days) and eclosion to laying egg stage (1.85 days).

This study aims at identifying pathogens contaminating seeds of rice cultivar Jasmine 85 in An Giang to study disease control methods. A total of 36 seed samples was collected from nine main rice cultivation areas of An Giang, i.e., Châu Đốc, Thoại Sơn, Tịnh Biên, Tri Tôn, An Phú, Châu Thành, Châu Phú, Long Xuyên and Chợ Mới. Seven fungal pathogens were identified based on their morphological characterization using blotter method. They include Alternaria padwickii, Bipolaris oryzae, Sarocladium oryzae, Aspergillus sp., Fusarium moniliforme, Mucor sp. and Penicilium sp. Two bacterial pathogens Pseudomonas glumae and Xanthomonas oryzae pv. oryzae were furthermore identified from the samples. The bacterium Pseudomonas glumae was detected based on its colony mophorlogy on selective media whereas Koch’s postulates combined with PCR technique using specific primers were used to identify Xanthomonas oryzae pv. oryzae. These results serve as a basis for effective control of seed transmitted diseases in rice fields.

This study was aimed to determine the effect of foliar application of KNO3 on yield and quality of Xoan orange grown at Phung Hiep district, Hau Giang province. Experiments were carried out from March to October in 2016, using 3-years-old Xoan orange trees on Mat orange rootstock. Four treatments of the experiment, viz. four KNO3 concentrations – 0 (untreated control), 0.3; 0.5 and 0.7%, were arranged in a completely randomized design with five replications, each of which was equal to one tree. Foliar application of KNO3 was applied once at 30 days before harvest. Results showed that spraying KNO3 at 0.7% brought the best response in terms of size of fruit (78.1 mm height; 88.4 mm diameter); weight of fruit (245.6 g); vitamin C content (12.6 mg/100 g of wet sample); Brix (9.76%); peel’s color indexes (∆E =77.3; L*= 42.7; b*= 40.4).

The study is aimed to assess changes in farm size and land use as well as the current situation of agricultural land use management in Thoi Lai district, Can Tho city for the period 2010-2015, including: change in land use, land use efficiency; the shift of occupation and farm size of farm households in rural areas. Information and data were collected from secondary data sources, PRA surveys and KIP interviews at the study sites. Research results on the structure of land use by types of land use from 2010 to 2015 in Thoi Lai district showed that agricultural land occupies a large proportion with a downward tendency (89.5% in 2015 vs 91.8% in 2010), while non-agricultural land increased (9.0% in 2015 vs 7.2% in 2010). The number of agricultural households has decreased for five years (2010 - 2015) because of the shift of labor from agriculture to other industries due to the urbanization of the city. The research results also show a clear stratification in the size of land holdings of households, households with an average area of ​​0.8-1.5 ha occupied the majority.

The survey was carried out from July to November 2016. A total of 86 samples of fry natural striped catfish were collected in Rach Ngong river of Can Tho city. Fish specimens were observed for clinical signs and examined for parasites. Results showed that there were 8 genera of parasites as follow Myxobolus, Henneguya, Trichodina, Dactylogyrus, Gyrodactylus, Ichthyonyctus, Protoopalina and Bucephalopsis. There were five parasitic genera on the skin and gills and four genera in the intestines and stomach of fish. The number of parasites infected natural striped catfish was dependent on parasitic genus and the infected organs. The rate of Bucephalopsis was highest (88.5%; 3-49/lame) and the lowest was Gyrodactylus (31.2%; 1-3/lame). Almost fish specimens were healthy and hadn’t clinical signs.

The experiments were conducted in glass tank system, each contains 20 L of 20‰ seawater and well aerated. The study was carried out to determine the effect of LAB supplemented in feed on survival rate and the resistance to V. parahaemolyticus causing acute hepatopancreatic necrosis disease (AHPND) in whiteleg shrimp (Litopenaeus vannamei). The results showed that the survival rate of shrimp was very high from 82.23 to 92.23% in the treatment of LAB supplement and without challenged to V. parahaemolyticus, and not significantly different to the ĐCA treatment (87.77%). The highest survival rate was obtained in the treatment of LAB5 supplement (92.23%). Furthermore, shrimp did not show any symptoms of AHPND. In the V. parahaemolyticus challenged-treatments (VP), shrimp showed the typical clinical signs of AHPND. The mortality rate was highest in VP+LAB3 treatment (70.02%), followed by the ĐCD treatment (54.43%) and VP+LAB4 treatment (43.33%). By contrast, shrimp in the remaining treatments had the high survival rate (73.37% to 79.97%) and shrimp's hepatopancreas were less affected by AHPND by histopathological method.

Investigation was carried out to assess the effects of different densities and cultivation methods on growth and quality of sea grape (Caulerpa lentillifera J. Agardh, 1837) cultivated in tanks. A two-factor experiment was set up with two initial densities (0,5 kg/m2 and 1 kg/m2) in combination with two cultivation methods (bottom and tray hanging culture). Sea grape was cultivated in the 250-L tank covered with sandy substrate in the tank bottom, at salinity of 30 ppt and fishmeal used as nutrient source. After 30 days of cultivation, there was no significant interaction (p>0.05) between density and cultivation method for the growth rates, proportion of edible frond/thallus and proportion of commercial fronds of sea grape. The growth rate and yield of edible frond were significantly higher (p

This study was conducted from January 2016 to December 2016 through interviewing directly 100 shrimp farming farmers, including 50 farmers who have diseased ponds and 50 farmers who have no diseased ponds in order to evaluate financial impact of diseases on this model in Soc Trăng province. Results showed that harvesting productivity of diseased ponds (1.35±0.96 tons/ha/crop) was much lower than that of another group (7.75±4.19 tons/ha/crop). The households with disease ponds lost an average amount of 142±107 million VND/ha/crop, while households with no desease ponds had an average profit of 465±235 million VND/ha/crop. Binary logistic model, three factors affecting possibility of disease occurrence included water level of pond, stocking density, fry test. The most typical difficulty of the model was shrimp diseases.

This study is aimed to evaluate the morphological diversity of kissing gourami populations in the Mekong Delta. Meristic characters and morphometric measurements were analyzed on fresh specimens (21-40 samples/population). Fish samples were collected by pulling nets in the natural basin of Lang Sen wetland Reserve (Long An) and stocking ponds in four provinces including Tra Vinh, Dong Thap, Hau Giang and Can Tho. Coloration of kissing gourami included two common colors, pink and grey but significantly differed in frequencies among sampling locations. Meristic traits of all five populations fluctuated in similar ranges. However, all morphometric indices (ratios to standard body length or head length) significantly differed (p

The objective of this study is to evaluate the effects of adding different calcium concentrations into diet on growth and survival rate of black apple snail, Pila polita during nursing phase. There were 5 treatments and 3 replicates in each treatment as follow: 1). Pellet only (DC); 2). Pellet+1% calcium (Ca1); 3). Pellet+3% calcium (Ca3); 4). Pellet+5% calcium (Ca5); 5). Pellet+7% calcium (Ca7). Newly hatched snails with initial shell height and weight of 4.3mm and 0.06g were reared in the composite tanks (80×60 cm, water column of 30 cm) at the density of 50 ind/tank. After 40 days of rearing, snails in Ca5 reached highest body weight (2.04 g) and shell height (18.37mm) compared to those in DC (1.51 g and 16.36 mm), Ca1 (1.85 g and 17.65 mm), Ca3 (1.96 g and 18.12mm) or Ca7 (1.80 g and 17.72 mm). The survival rate of snails was not significant difference among treatments (p>0.05). Feeding with Ca5, snails also obtained highest productivity (133.91 g/m2) and that was significant difference (p

This study was carried out to determine the effects of nitrite on some physiological parameters and growth performance of ba sa catfish (Pangasius bocourti). The study was triplicated and consisted of 4 treatments with diffenrent nitrite level (Control – 0mM, 0.09 mM, 0.22 mM and 0.44 mM NO2-). The first experiment of the study was performed in two weeks and the blood samples were collected at 0 hours, 24 hours, 48 hours, 72 hours, 96 hours, 7 days and 14 days after exposure to nitrite to evaluate parameters such as number of red blood cells, hemoglobin concentration, hematocrit, metHb, glucose, [Cl-] and [NO2-] in plasma. In growth performance experiment, ba sa catfish was reared for 60 days in nitrite exposed condition. The results showed that the number of red blood cells, hemoglobin concentration, hematocrit and [Cl-] were significantly decreased while metHb and [NO2-] in plasma of fish were increased after exposure to nitrite of 0.22 mM and 0.44 mM NO2- treatments. Besides, weight gain, DWG and SGR were significantly decreased while FCR increased in the treatments of 0.22 mM and 0.44 mM NO2- after 60 days (p

Studying snakehead fish farming system was conducted in An Giang province from January to May 2015 through interviewing 33 households for analyzing technical and financial aspects, and identifying advantages and disadvantages of the farming system. The results showed that snakehead fish farming system could be conducted with 2 crops/year. The average area was 0.12 ha/pond. The fingerlings were stocked in pond with 824 individuals/kg of size and 26.4 individuals/m2 of density. After 170 days of culture, snakehead fish were harvested with average yield of 123 tons/ha/crop, survival ratio of 60% and FCR of 1.15. With production cost of 3,530 million VND/ha/crop, gross income of 3,774 million VND/ha/crop, net income was 244 million VND/ha/crop and benefit ratio was 0.07 times, the ratio of unsuccessful households was 12.1%. However, this farming system has been faced with some difficulties such as low prices of fish and high feed costs