Vol. 15 No. 5 (2017)

Shaggy Inkcap, Coprinus comatus (O. F. Muller) has a high medical and nutitrional value and can be cultured in Viet Nam. In this study, the effect of composition and moisture of the subtrate and temperature and air humidity on growth and development of fruiting bodies of shaggy inkcapwere evaluated. The results showed that the optimium subtrate contained 45% corn cob, 44% cotton waste, 5% corn powder, 5%, rice bran and 1% CaCO3. The most suitable substrate moisture and temperature for culture of Shaggy ink cap were 65±3% and 18±20C, respectively. The relative air humidity favorable for growth and development of Shaggy inkcap fruiting bodies was 85%.

This study aimed at providing an up-to-date information on the molecular epidemiology of porcine circovirus type 2 (PCV2) circulating in Vietnam with a focus on the spatio-temporal dynamics of a newly defined PCV2d genotype. The results revealed a presence of multiple genotypes/clusters of PCV2, such as 1A/1B, circulating recombinant form (CRF) of PCV2b, and PCV2d. In northern, central and southern Vietnam, a co-circulation of multiple genetic clusters of PCV2 was observed in each sampling location at the same time period. All field strains of PCV2d circulating in Vietnam from 2004- 2017 were predicted to have the most common recent ancestor originated from China, however, they located at different branches of the PCV2d- phylogenetic tree.

The study was conducted on 11 Dong Tao cocks (8 - 10 months of age) at the chicken farm, Faculty of Animal Science, Vietnam National University of Agriculture to evaluate the semen quality and factors (individual, time of semen collection and storage condition) affecting semen quality from January to December 2016. The results showed that Dong Tao cocks had good semen quality in terms of ejaculation volume, pH, motility and sperm concentration. The semen color was 2.60 (between white to milk color) and the activity of sperms was 3.99 (well moving with waves at moderate level). The individuality factor affected all criteria of semen quality (P < 0.05). The motility and concentration of sperms collected in the morning were higher than those collected in the afternoon (P < 0.05). Sperm motility of diluted semen kept in the cold storage (2 - 10oC) was higher than that kept at room temperature (P < 0.05).

This study aimedto assess and select marine fish cage farming model in response to climate change in Cat Ba, Hai Phongforsustainable development of small-scale marine fish cage culture in North Vietnam under climate change context. The evaluation criteria focusedon infrastructure (3 criteria), culture techniques and cage management (7 criteria),and awareness and response to climate change (2 criteria). Each criterion was evaluated, scored on a 5 point scale (5 = very good, 4 = good, 3 = average, 2 = poor, 1 = weak). The assessment results found that most criteria wereabove average, except criteria on feed use and management, seed quality control, environmental management and disease prevention. Marine fish cages “Be 6” at Lan Ha bay, Cat Ba, Hai Phong had high overall score.and thus can be selected as the marine fish cage model for introductionto local marine cage farming communityto adapt to climate change.

The effect of weaning from conversion of live food (Artemia nauplius) to pellets on growth and survival of clownfish larvae (0 - 60 days old) was evaluated in this study. The same weaning regime was applied to larvae at day 14, 18, 22, 26 and 30 after hatching. The results showedthat clownfish larvae could start digesting pellets effectively from day 18 after hatching and still achieved optimal growth and survival rate. However, the use of the pellets at the earlier stage (day 14) caused a decrease in growth compared to weaning day 22, 26 and 30 post hatching (P < 0.05). The starting time of weaning had no significant effect on survival rate, ranging from 52.2 to 57.8% (P > 0.05). The use of pelletsreduced the period of weaning to 18 days post hatching as compared to30 days using Artemia nauplius,thereby improvingthe economic and technical efficiency in larval rearing.

chúng tôi tiến hành xác định thành phần hóa học, giá trị năng lượng trao đổi (ME) của thóc và gạo xay làm thức ăn cho gà bằng phương pháp trực tiếp Farrell (1978). Mẫu nghiên cứu được lấy từ 6 giống lúa trồng phổ biến ở Việt Nam là Bắc Ưu, BC 15, Khang Dân, Q5, Tạp giao và IR50404. Kết quả cho thấy thành phần hóa học và giá trị ME của thóc và gạo xay biến động theo các giống lúa. Hàm lượng protein thô, lipit thô, xơ thô, tro thô và DXKN (Dẫn xuất không nitơ) của thóc 6 giống lúa tương ứng (theo 100% vật chất khô) là 7,36 - 8,78%; 3,43 - 3,97%; 7,88 - 11,62%; 1,88 - 4,31% và 73,22 - 78,23%. Với gạo xay, các giá trị tương ứng là 8,00 - 10,91%; 2,85 - 4,96%; 1,48 - 2,32%; 1,09 - 1,66% và 81,43 - 85,77%. Giá trị ME thóc và gạo xay được xác định trực tiếp trên gà là 3,134 - 3,490 kcal và 3,668 - 3,884 kcal/g vật chất khô.

For establishment of the legal documents for controlling the use of Ractopamine (Ract) and Salbutamol (Salb) as feed additives in pig production, the experiment was carried out to evaluate the impact of supplementation of Ractopamine and Salbutamol on growth performance, and more importantly, the excretion behaviors of these additives and their residues in some edible tissues. The tested diets were (i) basal diet without any supplementation of either Ract or Salb (Control diet), (ii) basal diet added with 10ppm Ract (Ract diet), and (iii) basal diet added with 8 ppm Salb (Salb diet). Forty five fattening pigs with initial average body weight of 60 ± 3,0 kg were randomly allocated to the three treatments. Pigs were fed the experimental diets for the first 30 days (phase 1) following by a common basal diet to all the three treatment groups for another 30 days (phase 2). Each treatment consisted of three replicates with 5 pigs each. The nutrient requirements of the basal diet were formulated according to recommendation for the commercial pigs raised under the condition of Vietnam. Growth performance and carcass quality were accessed and Ract and Salb residues in urine and some tissues were tested after withdrawing the supplemented additives (phase 2). The results showed that supplementation of either Ract and Salb to the finisher diet significantly enhanced performance in pigs in terms of weight gain by 13.2% and 16%, respectively) but decreased FCR by 15.8% and 20.6%, respectively. Moreover, the Racr and Salb supplementation to diet improved some carcass traits as well as lean meat colour. Regarding urinary excretion, pigs fed Ract and Salb needed five and seven days, respectively, to completely excrete via urine. After withdrawing, the residues were still detectable in the fat and lean tissues in pigs fed either Salb or Ract until 5 days and became negative on 6 days in both groups. This result should be taken into consideration for establishing the protocol in controlling these prohibited substances as feed additives in pig production.

The study aimedto investigate the implementation of some land use rights (LUR) in Tu Son Town and proposedsolutions to improve the efficiency of implementation of LUR. The results showed that in the period 2010 - 2015, there were 4,293 transfer transactions, 1,757 donation transactions,7,915 mortgage transactions and 1,074 inheritance transactions in Tu Son Town. The procedure for implementing LUR at the Land Registration Office was easy to understand and implement. Most of the transactions were done according to the appointment.Theimplementation ofregulations related to LURandthe search forLUR transactions were relatively easy. However, fees, taxes and transfer taxes were high. In order to improve the effectiveness of implementation of LUR in Tu Son Town, the following comprehensive measures should be taken:enhancingpropagationand dissemination of laws, simplifyingimplementation procedures of LUR, increasing investment in facilities completingthe land use levy collection policy and buildinga comprehensive land database.

This study examined spatial and temporal variation in phytoplankton communities and physico-chemical water properties in Ba Lai River. Phytoplankton and water samples were collected at 8 different stations in two surveys during March (dry season) and September (rainy season) 2016. A total of 104 species belonging to four groups, namely blue greens algae, diatom, green algae and dinoflagellates were recorded with a clear dominance of Bacillariophyceae. The average abundances were 2010 cells/L and 1620 cells/L in in dry and wet seasons, respectively. Species diversity increased from Ba Lai sluice gate-dam towards the river mouth and the upper section. Results of canonical correspondence analysis (CCA) indicated that the phytoplankton assemblage was influenced by total dissolved solids, salinity and nutrient concentrations.

This research describes the result of isolation and selection of endophytic bacteria which is considered useful for plant growth from the Thionic Fluvisols in Kien Thuy district, Hai Phong for applying in agricultural production and environmental protection. The endophytic microorganisms were selected by assessment of IAA production, inorganic phosphorus solubilizing, cellulase and amylase synthesis and pH and temperature adaptability. Of the 120 strains isolated from plant at Thionic Fluvisols region, 8 endophytic bacteria strains were selected including 2 trains belongs to Pseudomonasgenus, 3 strains of Azospirillum, 2 strains of Burkholderiaand 1 strain of Klebsiellawith strong hydrolysis enzymes and phosphorus solubilizing,high ability in plant growth production (IAA), wide pH and temperature adaption. These microorganisms will be promising solutionsfor using and reclamation ofThionic Fluvisols.

The aim of this study was to select and use the endophytic microorganism strains from different ecosystems for the production of multifunctional biofertilizer formulation for crop plants. The endophytic microorganisms were selected for their IAA and hydrolytic enzyme production, phosphorus solubilization, and antagonism to pathogenic microorganims. Six endophytic bacterial strains, 3TDG1, 3TDG4, 3TDG5, 3LC2, 3LDQ2 and 3CL2, with high bioactivity were selected from 32 endophytic bacteria strains. These strains were used for adding into the nutrient liquid obtained from treatment of livestock waste for the production of multifunctional biofertilizer formulation. These strains were 99% homologous with Klebsiella pneumoniae strain PSB1, Klebsiella oxytoca strain ALK033, Aeromonas caviae strain J5; Pseudomonas putida strain E1-4, Pantoea rodasii strain Y36 and Bacillus subtilis strain QB5413, respectively. The yield of Basella alba L. in tetsting experiment fertilized with multifunctional formulation increased by 89.51% as compared with the use of NPK fertilizer.

Appropriate conditions for the extraction of phenolic compounds and 2,2-diphenyl-1-picrylhydrazyl (DPPH) antioxidant activity of seedy banana (Musa balbisiana)were determined using the conventional liquid-solid method. Total phenolic content and antioxidant activity were influenced by type and concentration of solvent, solid/liquid ratio, temperature, and extraction time. The optimal conditions for the antioxidant phenolic extraction were as follows: acetone concentration 60% (v/v); solid/liquid ratio1/30; at 40oC in 60 minutes. Seedy banana presented total phenolic content and DPPH scavenging activity of 15.47 ± 0.45 mg Acid gallic Equivalents per g of dry matter and 103.38 ± 3.65 mol trolox equivalents per g of dry matter, respectively. This study showed that seedy banana may be considered as a potential source of nutraceuticals applicable in food and drug technologies in the future.

In the present study, we propagatedHibicus sagittifoliusKurz plants usingstem nodalculture. After 30 days of culture, the results showed that MS medium supplemented with 0.3 mg/l BA, 0,1 mg/l NAA, 30 g/l sucrose, 8 g/l agar, pH 5.8 was the best medium for shoot regeneration and growth (5.00 shoots at the height of 3.65 cm). First stem nodes to fourth stem nodes were suitable materials for in vitroculture of Hibicus sagittifoliusKurz (3.00 - 6.90 shoot/explant). In the same culture medium, all samples did not regenerate the root in medium without activated charcoal, but when supplemented with activated charcoal, 100% samples regenerated root and shoot growth.MS medium containing 0.1 - 1 mg/l IBA, 30 g/l sucrose, 8 g/l agar, pH 5.8 was suitable for root regeneration. Coconut fiber powder was suitable substrate for the transfer of plantlets to greenhouse.Hibicus sagittifoliusKurz plantlets flowered after 80 days cultivation when grown on coconut fiber powdersubstrate.

The objectives of this study were to evaluate the capacity of indigenous N, P, K, Ca, Mg supply and to compare the nutrients uptake of maize in conditions of deposited and undeposited alluvial soils. The on-farm research was conducted on 10 farmers′ fields on each soil series. The experiment consisted of the following treatments (i) fully fertilized plot (NPKCaMg); (ii) nitrogen omission plot; (iii) phosphorus omission plot; (iv) potassium omission plot; (v) calcium omission plot; (vi) magnesium omission plot and (vii) farmers’ fertilization practice (FFP). Results showed that the deposited alluvial soil supplied higher amount of nitrogen and magnesium than undeposited alluvial soil. The amount of N, P, K, Ca and Mg (kg N, P2O5, K2O, CaO, MgO ha-1) provided 84, 112, 152, 30, 75 kg ha-1 under deposited alluvial soil and 68, 116, 158, 46, 45 kg ha-1 under undeposited alluvial soil. Without application of individual N, P, K, Ca and Mg element correspodingly reduced N, P, K, Ca, Mg removal on both soil types. The N and MgO uptake by maize on deposited alluvial soil was higher than that of on undeposited alluvial soil.

The research usedan econometric model,Exploratory Factor Analysis (EFA),to clarify factors affecting the efficiency of agriculturalextension in Nhu Thanh district, Thanh Hoa province. The data werecollected through surveying 120 samples with 21 observed independent variables in 2015. By using EFA model, the research found out there were 5 mainaffecting factors, including agriculturalextension policy,extension content,agriculturalextensionfacilites and the sympathyof agriculturalextension staff. As a result, the research suggested4 groups of solutions to improve efficiency of agriculturalextension in Nhu Thanh district, viz.completion of extension policies, renewal of the program and contents of extension training activities, enhancing capital support, renewing the agricultural production model, strengthening the mechanism of socialization in agricultural extension, increasing people participation, and applying advanced techniques to agricultural production

The compliance with pesticide use principles is required in agriculture production, especially in vegetable production due to its relation to food safety, human health, environment and economic efficiency. This study used primary data from a survey of 99 vegetable farmng households in Thanh Hoa city to evaluate the situation and determine the factors affecting the farmers’ compliance with pesticide use principles. Exploratory Factor Analysis with 25 specific criteria was used to determine the impact of each principle on farmers’ compliance. The results showed that the “Right pesticide for a right crop’’ principle had the highest impact, followed by the principles "Right method of application" and “Right dose and ingredient’’. Therefore, to enhance the famers’ compliance with pesticide use principles, it is necessary to strengthen the propaganda, training, management and supervision on the pesticide use according to the priority of the impact level of the aforementioned principles.

Shrimp is the major commodityin the annual export turnover of Vietnam. This paper analyzedproductive efficiencyof the intensive white-leg shrimp farming households in Phu Yen. A total of 59 shrimp farming households practicing intensive aquaculture with the area of 45 ha (about 24% of the intensive white-leg shrimp farming in Phu Yen province) were randomly surveyed. The result showedthat although the intensive white-leg shrimp farming in Phu Yen is still profitable,but the interest for investment in shrimpfarming is rather low due to high risk and high productive capital. Moreover, this aquaculture is only profitable if its negative impact on the environment is neglected. The saturation state due to open-access mechanism for aquaculture has, however, been reached. Toward a sustainable aquaculture, it requires a further revision and issuing policies that step by step endogenize the environmental costs into the production process. Farmers’supports such as technology development, technique training and credit acess are also important.