This experiment began from March to May 2011 at college of Aquaculture and Fishieries of Can Tho University based on the common methods used to study the biology of fish. Fishes were determined from 1 to 50 days after ? hatching. The result showed that the non ? biological temperature was 11.60C. The yolk absorption period lasted to tenth day after hatching. The lower and upper temperature tolerance fluctuated from 10.1 to 110C and  from 41 to 41.70C, respectively. The oxygen tolerance increased from 0.53 to 0.77 mgO2/L, but the oxygen consumption decreased from 2.23 to 0.29 mgO2/g.h. The upper pH tolerance was 10.5, but the lower pH tolerance was decreasing from 4.5 to 3.5. The sanility tolerance of fish from 1 to 20 days after hatching was 11? but of fish from 30 to 50 days after hatching was 12?.

Study on natural immune response of freshwater prawn (Macrobrachium rosenbergii) which were experimental infected with white spot syndrome virus was performed. Prawns were injected into second abdominal segment. WSSV with three concentrations as LD50, LD50.10-2, LD50.10-4 and a control treatment (PBS injection).  Haemolymph samples were collected at day 0, 1 ,3, 5, 10, 15 after injection for analyzing total haemocyte count, haemocyte identification, phenoloxidase, respiratory burst and superoxide dismutase activities. Results of immunological analysis revealed no difference in total haemocyte count of all the treatments as well as sampling times. Granular cell reduced until 5 day after injection. Phenoloxidase and respiratory burst activities were found to be significantly higher in infected prawns compared to non-infected ones, but superoxide dismutase activity was lower than those of the first sampling time and control treatment.

Salinity intrusion is one of the major problems that the Mekong Delta is facing. It would increase in the future due to sea level rise and upstream flow decline. In this study, salinity intrusion in Mekong Delta was simulated by using MIKE11 under climate change and upstream flow reduction scenarios. The model constructed by using topographical in 1998 and 2005. The simulation result for the year 1998 was chosen as baseline scenario to measure any changes in salinity intrusion in the year 2020 and 2030. Four modeling scenarios were set up basing on their results from the SRES B2 scenario, CC-NoAgri (No Change in Agricultural) scenario and CC-Agri (Change in Agricultural) scenario. The two first scenarios and the rest were respectively in the year 2020 and 2030. In the first and second scenario, sea level was projected to rise up to 14cm while upstream discharge rate of Mekong River was assumed to decrease 11% for the first scenario and 22% for the second one. In the third and the forth scenario, sea level increased 20cm but upstream discharge rate declined 15% in the third scenario and fell twice as much in the forth scenario. The result obtained, namely 2.5g/l saline likely shifted 14km to upstream in main rivers in comparison to serious salinity intrusion time in 1998. Also, saline intrusion area was expanded most of saline intrusion projects in Mekong Delta.   

Tri Ton district of An Giang province is located in the South West direction, Mekong Delta with the natural area is almost mountainous. Therefore, local farmers have always encountered with many difficulties in agricultural production. So, the identification of  main problems in cultivation is a important issue helping for land use planning effectively in the area. The results of soil survey at three representative study locations and field investigation of 60 farmer households in the area showed the main constraints, it consists of: water resource for irrigation is extremely limited in dry season, specially on high land and deeply flooded on low land; agricultural production is mainly by rainfed; soil tilled by animal; imbalanced in inorganic fertilizer and not suitable pesticides application. So, strengthening the agricultural extension work and irrigation system contruction are the vital important activities for improvement the land utilization types and sustainable agricultural production. Finally, it will contribute to increase famers?s income at Bay Nui region of Tri Ton and Tinh Bien district, An Giang province.

Toxicity of nitrite (NO2-) has been well documented in the culture of fishes, but not much in shrimps. In this study, freshwater prawns Macrobrachium rosenbergii (9.69 ± 1.04 g; 9.87 ± 0.48 cm) were exposed to nitrite (NO2-) to determine 96h-LC50value. The growth, molting cycle and frequency of prawns were examined as prawns were exposed individually to 0 mg/L (control), 1.4, 2.81, 8.04 and 14.1 mg/L nitrite. The experiment was performed over a 90 day period in order to provide biological data for improving farming techniques. Results showed that M. rosenbergii (9.6 9± 1.04 g; 9.87 ± 0.48 cm) were sensitive to nitrite, the 96-h LC50 of nitrite on prawns was 28.08 mg/L NO2-N. The growth (SGR) of the prawns reared in 2.81 mg/L, 8.04 mg/L and 14.1 mg/L NO2-N was significantly lower (P

The paper describes the importance of small scale decentralized domestic wastewater treatment using ?reed bed? system in the Mekong Delta of Vietnam with example where the system provides good quality of effluent discharge. A pilot-scale sand-based horizontal subsurface flow constructed wetlands (HSSF CWs) planted with Phragmites sp. was built in Campus I, Cantho Univeristy. The system was operated at two hydraulic loading rates (HLRs) of 31 and 62 mm/d. Removals of TSS, PO4-P and TP were efficient and similar at both HLRs with mean removal rates of about 94, 99 and 99%, respectively, while removals of BOD5, COD, TKN and NH4-N decreased with HLRs increased, and were in range of 47-71, 68-84, 63-87 and 69-91%, respectively. The results indicated that using HSSF CWs for domestic wastewater treatment was viable technique. Effluent quality at high HLR of 62 mm/d (i.e. 1200 L/d) was within the permitted Vietnamese standard for discharge into surface water.

This study aimed to evaluate the effects of different methods to supply probiotics into the algae medium (indirect) or cultured tanks (direct supplementation) during seed nursing of clam. Juvenile clams (SL: 11.85 ± 0.33mm) were cultured at a density of 40 individuals per 100L tank. Clams were fed daily with algae from Tilapia - green water system at the density 10,000 cells/ml. Probiotics containing Bacillus subtillis and Lactobacillus acidophilus are added at 0.5mg/L in seven day intervals. After 90 days of experiment, the highest survival rate (98.33%,) was observed in direct supplemented treatment, which were significantly different from other treatments (P

Investigating the distribution of zooplankton on Caikhe canal was carried out every week in the low and high tide in the same day from January to March, 2010. Results showed that the taxa of rotifera and protozoan increased from the Hau river to the inner of Caikhe canal. The rotifera taxa took apart from 51 to 100% on the composition, particularly the species Filinia longiseta always appear in the sampling times and sampling positions. The Copepod taxa were poor and rare. The density of zooplankton fluctuated from 11334 to 845405 ind./m3, in which rotifera took apart of 11% - 100% on amount of invertebrate plankton. Particularly amount of Filinia longiseta was found with the ratio of 45.3 - 93.5% at the position around Nguyen Van Cu bridge where is the most polluted area.

Protocol for DNA extraction from blood of stripped catfish and PCR protocols for detection of Edwardsiella ictaluri, Aeromonas hydrophila and Flavobacterium columnare bacteria were optimized and applied. The optimized PCR protocol for detection of          E. ictaluri bacteria gave a PCR product of 407 bp and detection sensitivity was  4.5x104 CFU/ml of bacteria in 100 ml catfish blood. The optimized PCR protocol for detection of A. hydrophila bacteria gave a PCR product of 209 bp and detection sensitivity was  4.5x166 CFU/ml of bacteria in 100 ml catfish blood. The optimized PCR protocol for detection of F. columnare bacteria gave a PCR product of 504 bp and detection sensitivity was  4.5x163 CFU/ml of bacteria in 100 ml catfish blood. These PCR protocols were used to detect respective bacteria in blood samples of experimental injection catfish. The obtained results showed that optimized PCR protocols can be used as a non destructive methods for rapid, sensitive and specific detection of bacterial infection        in catfish.

The sex pheromone of the sweet potato weevil (Cylas formicarius Fab.), (Z)-3-dodecenyl-(E)-2-butenoate compound (Z3-12:E2), was synthesized by a synthetic route via the Wittig reaction with starting reagents were 1,3-propanediol and 1-nonanal. In a field test, Z3-12:E2 at any dose from 0.1 to 1.0 mg gave the same attraction to C. formicarius males with numbers of captured males were significantly higher than that of control. Otherwise, at 0.3 mg dose, there was not significantly different in the numbers of captured males between traps baited with unpurified and purified Z3-12:E2.

Optimum application for the sex pheromone of the sweet potato weevil, Cylas formicarius Fab., in filed were investigated in laboratory and field conditions. Amongst tested solutions, water-soap (7 g soap in 300 ml water) was the best in killing the sweet potato weevils, and thus it is also best for making a water-trap. Results of field evaluations proved that Vietnamese rubber septa and water trap were absolutely able to replace imported rubber septa and sticky trap in preparation of lure and trapping of the weevils. On the other hand, the height of trap setting and color of trap were not effect on the attraction of pheromone lure.

A study of hypotonic shock treament by trisodium citrate (C6H5Na3O7) 0,4% in 30 ? 60 minutes prior to the mitotic peak time of the radicle, rootlet, gemma leaf and young leaf samples of cultivated banana (Musa paradisiaca L.), seedless watermelon F1 TN736, Allium ascalonicum L., Allium cepa L., Pisum sativum L. and 9 species of family Araceae were effected. Somatic animal cells as brains and salivary glands of third instar larvae (Drosophila sp.) treated by NaCl 0,5% and the grasshopper?s testes treated by NaCl 0,5% in 10 minutes before fixation in modified Carnoy?s solution and stain in 1% aceto-carmine solution showed high quality miotic and meiotic chromosome spreads. Chromosome numbers of studied cells were investigated. Over-treatment with hypotonic solution resulted in rupturing of cells, scattering and lossing of chromosomes.

Sand lobster (Thenus orientalis) is among highly priced seafood delicacies worldwide. In its life cycle, planktonic larval stages are prolonged and complex. Due to this life history characteristics along with delicate shape and weakness of larvae, larval rearing of sand lobster in captive conditions has been challenging. This study aimed to evaluate effects of different feeding regimes on larval rearing. An experiment including 4 feeding treatments was carried out in tanks containing 50 L of water with salinity at 30%o. Larvae were fed with newly-hatched Artemia and blood cockle meat added at different rearing time from (1) the 1st day, (2) the 3rd day, (3) the 6th day, and (4) the control without blood cockle meat. The results showed that larvae in treatment 1 had the highest survival rate, the longest survival duration (26 days) and better growth rate than those in the other treatments. Larvae fed with Artemia alone survived only 9 days. Although Phyllosoma larvae couldn?t metamorphose to Nisto stage, this study provided important information for further research on larvae rearing of this species.

The study on ?Somatic embryogenesis and shoot regeneration of Dendrocalamus giganteus Wall. ex Munro from thin cell layer of micropropagated immature stem? was conducted at the lab of Plant Tissue Culture of Plant Physiology and Biochemistry Department, College of Agriculture and Applied Biology, Can Tho University, from January 2010 to April 2011. The results showed that: (i) Thin cell layer of micropropagated immature stem induced highest ratios of calli induction (81.34%) and compact calli formation (64.77%) on MS medium supplemented with NAA 2 mg/l and 2,4-D 7 mg/l after 8 weeks culture; (ii) This identified medium was also effective for calli development stages; (iii) From calli, somatic embryogenesis could initiate on MS medium supplemented with TDZ 0.01 mg/l (33.33%) after 3 weeks culture, and most of shoots grew very well.

The protocols for determination of several innate immunological parameters in prawn (Macrobrachium rosenbergii) were optimized. These protocols include: (1) procedures for total haemocyte count by using haemocytometer and for haemocyte identification which can determine 2  kinds of haemocytes in blood sample; (2) Protocols for analysis of phenoloxidase, respiratory burst and superoxide dismutase activities by creating colour complexes and measured by absorb wavelength of 490 nm, 630 nm and 560 nm, respectively. The optimized protocols were used to determine innate immunological parameters in prawns which were experimentally challenged with white spot syndrome virus. The obtained result revealed a signi?cant change (P

This study aimed to ameliorate the excessive amounts of organic nitrogen (N) and phosphorus (P) accumulated in ponds used for intensive catfish (Pangasianodon hypophthalmus) cultivation in the Mekong River Delta. To this end, water hyacinth (Eichhornia crassipes) and vetiver (Vetiver zizanioides) were selected to test their capacity in reducing these dissolved organic compounds. The study was conducted by growing these plants in the culture containing high concentrations of dissolved organic N and P supplied from Glycine and Glucose 1-phosphate. The changes in the amounts of organic N and P compounds were monitored through the growth of these plants. The results showed that both water hyacinth and vetiver could perform well in the media in which mineral N and P were replaced by organic forms. After one month, water hyacinth could reduce 88% organic N and 100% organic P as compared to their initial concentrations. Similarility, the concentrations of organic N and P reduced by 85% and 99% respectively when vetiver was grown in the culture. These results were validated by growing these plants in the water samples taken from catfish ponds and investigating the reduce in organic N and P concentrations over time. Our results confirmed that both water hyacinth and vetiver are promising to use in ameliorating the contamination of organic N and P drained from catfish ponds.

A study was conducted on dairy cows, dogs and rats in and around Song Hau Food Processing Joint Stock Corporation by using Microscopic Agglutination Test (MAT) with 23  Leptospira serovars. Leptospira trains was found in highest rate in rats (55.55%, followed in dogs (40.47%) and lowest in dairy cows (22.61%).  Leptospira positive rate from dairy cow and dog age groups were not significant difference. There was no significant difference of Leptospira infected rate in dogs and rats by sex. In dairy cow,  most of samples were positive at titer from 1:100 to 1:400, in rats from 1:100 to 1:200, in dogs 1:100.  In rat, there were highest number of serovars (22 serovars), in dairy cow (16 serovars), in dog (11 serovars). All of serovars, which we found in dairy cows and dogs, were also found simultaneously in rats. Leptospira serovars mix-infection was found diversity such as  in rat (2-6 serovars per each), in dairy cows and dogs (2-3 serovars per each). Out of 22 serovars, there were 9 serovars that found in dairy cows, dogs and rats simultaneously. Rats were carrier and secretion of Leptospira, especially, 6 serovars as L. bataviae bataviae Van Tienen, L. ballum castellonis castellon 3, L. pyrogenes pyrogenes Salinem, icterohaemorrhagiae Tonkini LT9668, L. sejroe hardjo Hardljoprajitno, L. tarassovi tarassovi Mitis Johnson. Rats may be a source of Leptospira distribute to cows and dogs in this farm, with R2 (0.77).

Pangasianodon hypophthalmus is highly commercial valuable  fish in Vietnam. However, there are not many published papers on the effects of salinities on the physiological characteristic of the stripped catfish while the sea water levels is predicted to increase 12cm in 2020 and 75cm in 2105 (http://tinkhoahoc.blogspot.com, Nguyen Ngoc Tran, 2011). This paper was studied on the tolerant of the eggs and larvae of tra catfish in different salinies. The eggs of the stripped catfish after artificial fertilized were incubated in the freshwater( 0? control), 1?, 3?, 5?, 7?, 9?, 11?, 13?, 15?, 17? and 19?. The embryonic development time, hatching time and rate were observed. After hatching the larvae were nursed in the tanks (500L) about 2 months in the same media of salinities at hatching. The osmotic and ionic concentrations in the plasma of fish in different salinities were measured. The results showed that the embryo of the stripped catfish can develop and hatch in brackish water (0-11 ?), the embryonic development time prolonged from 23 to 38 hours when the embryo were incubated in freshwater to 23? and the hatching rate decreased from freshwater to the brackish (68,54-25,87%). In adition, water osmotic levels of the fish increased in the freshwater treatment (225 ± 42,68 mOsm/kg) to 23? (506 ± 43,76 mOsm/kg), isomotic of fish was 9? (283 ± 34,66 mOsm/kg). Chloride and sodium ion concentrations increased conciding to the increasing salinity from 0 to 23? (91 - 218 mM/L, 71 - 163 mM/L, respectively), K+ levels in the blood of fish are always higher than those in water.

Nitrogen is the most important nutrient which is needed for growth, develop stage and yield of low-land rice. When chemical fertilize are used, soils become unfertile and compact. In addition, the extra uses of chemical fertilizers contributed to the enviromental pollution and human health. To decrease those problems and keep a sustainable agriculture, this experiment was carried out to determine nitrogen-fixing capability of Azospirillum lipoferum R29B1 bacteria. Then, the effectiveness of this bacteria on the growth and yield of rice was evaluated. The results indicated that rice inoculated with Azospirillum lipoferum R29B1 strains and applied 50N had higher yield components than the control and equivalent to that of rice applied 100N without inoculation in the green house.

The effects of different dissolved oxygen concentrations on the growth, oxygen consumption and oxygen threshold of common carp (Cyprinus carpio) was studied in laboratory conditions. The growth study was conducted with 3 oxygen levels including 20%, 50% and 80% saturation; 40 fish (25,7±0,21 g initial weight) were stocked in each of nine 1 m3-composite tanks (three replicates for each treatment); the oxygen levels were auto-regulated by oxy guard system and the experiment lasted for 2 months. Oxygen comsumption and oxygen threshold of common carp at 3 mentioned oxygen levels were determined by two-taps flask method. Each treatment was repeated 6 times. The oxygen saturation concentration was adjusted using YSI DO meter and nitrogen. Results of the studies showed that a significantly higher growth rate and lower feed conversion ratio (p

Some biological characteristics of a braconid wasp, Microplitis manilae Ash., parasitized larvae of Spodoptera litura Fab., were investigated under the laboratory conditions (26?300C, 68?80% RH). Results showed that, a life cycle of M. manilae was 14.0 ± 1,3 days including the time from egg to pupa was 8.2 ± 0.7 days, pupal stage was 4.8 ± 0.6 days and the time from eclosion to a female laid egg was 1 day.  Adult longevity was 10.3 ± 2.5 days. Number of M. manilae larvae developed from egg of a female fluctuated in the range of 77 to 139 larvae (average 101 ± 20.3 larvae). The time for the larvae moved out their host to pupate was 11 days with two appearance peaks at the second and fifth days. Additionally, the number of M. manilae larvae emerged from the second instar larvae of S. litura was significantly different to that emerged from the third  instar larvae of S. litura.

mPCR protocol for simultaneous detection of Edwardsiella ictaluri, Aeromonas hydrophila and Flavobacterium columnare infection using blood samples from stripped catfish (Pangasianodon hypophthalmus) was optimized. The mPCR product has three bands 407 bp, 209 bp and 504 bp for E. ictaluri,  A. hydrophila and F. columnare, respectively. The lowest detection limit of mPCR protocol was 1.5x105 CFU/ml for         E. ictaluri and F. columnare and 1.5x106 CFU/ml for A. hydrophila in 100 ml catfish blood sample. The diagnostic sensitivity and specificity of the PCR was evaluated with common bacterial isolates in aquaculture including Vibrio harveyi, V. alginolyticus,      V. cholerae, Aeromonas sorbia; A. carviae, Pseudomonas putida, Eschericchia coli, Bacillus subtilis. The mPCR protocol was simultaneously used to detect respective bacteria in blood samples of experimental injection catfish. The obtained results showed that optimized PCR protocol can be used as a non destructive method for rapid, sensitive and specific detection of bacterial infection in catfish.

Fish diseases are of important problems to be considered in aquaculture, especially, in intensive system which more and more become popular. The aim of this study was to investigate pathogen infection to snakehead in intensive pond culture system in An Giang and Dong Thap provinces. A total of 296 samples, showing secretion of swimming lethargic, feeding reduction, mucus mass, red spots and white spots on the body and threadfin, were colected from the culture ponds in the period of March to August, 2010. The result indicated 23 genera of parasites, 4 genera of fungi and 4 genera of bacteria which infected to cultured snakehead. Six genera of parasites (Henneguya, Chilodonella, Epistylis, Tripartiella, Gnathostoma and Capillaria were identified for the first time. Fungi were defined in the first three months of culture period, of which, Achlya appeared only in the first sampling time. Three genera of fungi, Acremonium, Fusarium and Geotrichum were firstly isolated from cultured snakehead. Bacteria including Aeromonas, Edwardsiella, Streptococcus and Pseudomonas appeared at frequency of 54.3%, 17.3%, 14.8% and 13.6%, respectively.