Structure of Fucoidan from Brown Seaweed Turbinaria ornata as Studied by Electrospray Ionization Mass Spectrometry (ESIMS) and Small Angle X-ray Scattering (SAXS) Techniques

The purpose of this study is to elucidate both the chemical and conformational structure of an unfractionated fucoidan extracted from brown seaweed Turbinaria ornata collected at Nha-trang bay, Vietnam. Electrospray ionization mass spectrometry (ESI-MS) was used for determining the chemical structure and small angle X-ray scattering (SAXS) provided conformational of the structure at the molecular level. The results showed that the fucoidan has a sulfate content of 25.6% and is mainly composed of fucose and galactose residues (Fuc:Gal ≈ 3:1). ESIMS analysis suggested that the fucoidan has a backbone of 3-linked α-l-Fucp residues with branches, →4)-Galp(1→ at C-4 of the fucan chain. Sulfate groups are attached mostly at C-2 and sometimes at C-4 of both fucose and galactose residues. A molecular model of the fucoidan was built based on obtained chemical structure and scattering curves estimated from molecular model and observed SAXS measurement were fitted. The results indicated that fucoidan under study has a rod-like bulky chain conformation.     

A study of genetic diversity of sesame (<Emphasis Type="Italic">Sesamum indicum</Emphasis> L.) in Vietnam and Cambodia estimated by RAPD markers

Sesame (Sesamum indicum L.) is a traditional oil crop cultivated throughout South East Asia. To estimate the genetic diversity of this crop in parts at the region, 22 sesame accessions collected in Vietnam and Cambodia were analyzed using 10 RAPD markers. The 10 primers generated 107 amplification products of which 88 were polymorphic fragments (83%). Genetic diversity of all populations was H_t = 0.34 when estimated by Nei’s genetic diversity and species diversity was H′_sp = 0.513 when estimated by Shannon diversity index. Genetic distance ranged from 0.03 to 0.43, with a mean genetic distance of 0.23. The unweighted pair group method with arithmetic averages (UPGMA) cluster analysis for the 22 accessions divided the material in four groups. The dendrogram revealed a clear division among the sesame accessions based on their geographical region. Interestingly, some geographically distant accessions clustered in the same group, which might indicate the human factor involved in the spreading of sesame varieties. The high level of polymorphism shown suggests that RAPD techniques can also be useful for the selection of parents in sesame (Sesamum indicum L.) breeding program and for cultivar differentiation.     

Oral administration of Escherichia coli lipopolysaccharide enhances the immune system of striped catfish,Pangasianodon hypophthalmus (Sauvage)

Lipopolysaccharide (LPS), a component of Gram negative bacteria, was reported as important immunostimulant for fish. In this study, striped catfish were fed diets containing different Escherichia coli LPS concentrations (0%, 0.01% and 0.05%) for 2 weeks and then fed control feed (0% LPS) for 4 weeks. Plasma cortisol and glucose were rather low and did not differ significantly among treatments (P > 0.05). The respiratory burst activity, lysozyme, complement, total of antibody as well as mortality in fish challenged with Edwardsiella ictaluri were recorded every 2 weeks (W2, W4 and W6). The lysozyme activity significantly increased in fish treated with LPS (P < 0.05) in W2, W4 and W6. The highest values of respiratory burst activity were observed at week 4 in fish fed 0.01% LPS. There were significant differences in total of antibody between fish fed LPS (0.01%) and control in W2, W4. The challenge test with Edwardsiella ictaluri showed that fish fed 0.01% LPS had lower cumulative mortality (40%, 33% and 42%) compared with the fish fed 0.05% LPS (50%, 40% and 47%) and control fish (40%, 57% and 53%) in the three difference sampling times respectively. These results suggest that feed supplemented with 0.01% LPS could enhance immunity of striped catfish after 2 weeks of oral administration and fish could be protected against bacterial infection during the following 4 weeks.     

Reproductive performance in sows in relation to Japanese Encephalitis Virus seropositivity in an endemic area

Japanese Encephalitis Virus (JEV) is considered an important reproductive pathogen in pigs. Most studies of the reproductive impact of JEV have been conducted in areas where the disease occurs in seasonal epidemics. In this study, the associations between seropositivity for JEV, measured with an IgG ELISA, and the number of piglets born alive and stillborn were investigated in a tropical area endemic for JEV in Vietnam. Sixty percent of sows from four farms in the Mekong delta of Vietnam were seropositive to JEV and the Odds Ratio for a sow being infected was highest (6.4) in sows above 3.5 years (95% confidence interval 2.2–18.3). There was an association between increasing Optical Density (OD) values from the ELISA and the number of stillborn piglets in sows less than 1.5 years, but no effect of seropositivity could be shown when all sows were studied. OD values had an effect (p = 0.04) on the number of piglets born alive in the statistical analysis only when interacting with the effect of the breeds. An increase in mean OD value of the herd was correlated (p < 0.0001) with an increase in the number of piglets born alive. In this study, there was evidence of a negative association between seropositivity for JEV and the reproductive performance only in sows less than 1.5 years in endemic areas. This could be explained by a year-round infection with the virus, which would lead to immunity in many gilts before their first pregnancy. This, in turn, may imply that JEV infection in pigs is of minor importance for the reproductive performance in endemic areas.     

Participatory research on the effectiveness of drainage in the Red River Delta,Vietnam

The irrigation and drainage systems in the Red River Delta in Vietnam were designed and constructed in the 1950s and 60s. These systems are well established and provide water to virtually all of the irrigable land in the Delta. The land is cropped intensively: on average just over two crops a year. The irrigation and drainage systems are complex: dual purpose channels and pumping stations are used. In the 1990s, the systems were rehabilitated and upgraded. A review showed that irrigation projects performed reasonably well, but the two core drainage projects performed less than anticipated. In the Red River Delta, with its low elevations, drainage rather than irrigation is often the limiting factor affecting agricultural production. To investigate these constraints in more detail, a participatory research study on the effectiveness of drainage was conducted in two drainage areas in the Red River Delta. The study started with a participatory pre-investigation to identify and quantify the constraints in the functioning of the drainage systems. Next, the drainage system was modelled and computer simulations were used to develop conceptual designs to improve the functioning of the systems. Finally, recommendations to improve the institutional capacity of the drainage system management were formulated, again in close cooperation with the stakeholders. These recommendations cover a whole range of technical issues: small-scale improvements in the farmers’ fields, modifications in the main and secondary drainage systems, including the control structures, up to recommendations to increase the efficiency of the pumping stations. Next to these technical innovations, recommendations to reform the complex institutional setting have been formulated.     

Factors Affecting the Sustainable Development of Community-Managed Nurseries for Promoting Rare Conifer Species in North-West Vietnam

This study examines factors affecting the sustainable development of seven community-managed nurseries growing two rare and valuable indigenous conifer species—Fokienia hodginsii and Taiwania cryptomerioides—in the Hoang Lien Mountain range in North-West Vietnam. The nurseries were pilot programs of the Fauna and Flora International (FFI) project entitled Community Based Conservation of the Hoang Lien Mountain Ecosystem. FFI partnered with local government organisations and farmers to carry out the pilot program, with the objective of providing improvements in community livelihoods together with measurable conservation benefits. This study, completed in September 2006, revealed that the overall objectives of the pilot program were not achieved due to financial, management, and technical reasons. There was a lack of market demand for these two rare conifer seedlings. Farmers and State Forestry Enterprises (SFEs) prefer to invest in fast-growing species for an earlier return. Demand for the seedlings by National Parks (NPs) is nearly zero due to limited funds to purchase seedlings and the capacity of NP staff to produce seedlings of these two rare conifer species. These two species are not included in the approved list of species by the Ministry of Agriculture and Rural Development (MARD) for the 5 Million Hectare Program (5MHP). The seed germination rate in nurseries was typically low, nursery operators were not well trained by FFI technical staff, and most of them did not understand fully all stages to set up and operate nurseries. Also, the co-operation among partners in the pilot program was not effective due to local partners not fully understanding their responsibilities, hence farmers did not receive valuable advice when they met technical difficulties. The research suggests that future similar projects can be more effective if major planting programs include these two rare conifer species in the approved list. Farmers operating community-managed nurseries should have adequate training and technical support by SFEs and NPs. Community-managed nurseries require sales contracts for seedlings of rare species with local customers (SFEs, district 5MHP management board and NPs). International organisations can play a role in providing funds to start up projects and oversee the responsibility of each of the partners involved in these projects.     

Residual Organic Compound Removal from Aqueous Solution Using Commercial Coconut Shell Activated Carbon Modified by a Mixture of Seven Metal Salts

The modified activated carbon (MAC) derived from commercial coconut shell activated carbon (AC) with mixture of seven metal salts was used as an adsorbent to remove target residual organic compound (sucrose) from aqueous solutions in batch modes. The results indicated that the highest adsorption capacity of sucrose onto MAC reached when the AC was modified at the ratio of impregnation of AC with mixture of seven metal salts, including nitrate silver (AgNO₃), manganese nitrate (Mn (NO₃)₂), potassium bichromate (K₂Cr₂O₇), nitrate cobalt (Co (NO₃)₂·6H₂O), nitrate copper (Cu (NO₃)₂·3H₂O), nitrate nickel (Ni (NO₃)₂·6H₂O) and nitrate iron (Fe (NO₃)₂·9H₂O) of 3% (w/w). The most appropriate conditions for sucrose adsorption onto MAC in batch experiments obtained at pH 7, contact time of 120 min, 800 mg MAC/50 mL of sucrose solution with initial concentration of 1500 mg/L. At this condition, the highest adsorption capacity of sucrose onto MAC reached 28.28 mg/g. The Langmuir, Freundlich, and Sips adsorption isothermal equilibrium models can adequately describe the adsorption properties of sucrose on MAC. The adsorption kinetic of sucrose onto MAC obeyed pseudo-first-order and pseudo-second-order models with the chemical sorption process. The saturated MAC was recovered by heat from an oven. The highest recovery efficiency of saturated MAC obtained at 180 °C in 120 min. The highest adsorption capacity of sucrose onto recovered MAC was 24.31 mg/g, appropriately adsorption capacity of initial MAC.     

Spatial prediction of saline and sodic soils in rice‒shrimp farming land by using integrated artificial neural network/regression model and kriging

In the context of widespread saline and sodic soil, mapping and monitoring spatial distribution of soil salinity and sodicity are important for utilization and management in agriculture lands. In this study, two-stage assessment was proposed to predict spatial distribution of saline and sodic soils. First, artificial neural network (ANN) and multiple linear regressions (MLR) model were used to predict sodium adsorption ratio (SAR) and exchangeable sodium percentage (ESP) based on soil electrical conductivity (EC) and pH. Then, the Kriging interpolation method combined with overlay mapping technique was used to perform saline spatial predictions in the study area. The model accuracy level is evaluated based on coefficient of determination (R²) and root mean square error (RMSE). In the first stage, the values of R² and RMSE of SAR and ESP were 0.94, 0.17 and 0.94, 0.24 for ANN, and 0.35, 0.52 and 0.34, 0.76 for MLR, respectively. Similarly, in the second stage, the RMSE of ANN-Kriging were much closer to 0 and relatively lower than MLR-Kriging and Kriging. The results show that ANN-Kriging can be used to improve the accuracy of mapping and monitoring spatial distribution of saline and sodic soil in areas that develop the rice-shrimp cultivation model.     

Land Use After Forestland Allocation and the Potential for Farm Forestry in a Mountainous Region of Northeast Vietnam

As a response to serious deforestation in Vietnam, the forestland allocation (FLA) policy was introduced in the 1990s. The process still continues, having allocated 80% of the forestland to various management entities, among which individual households are the most important one for production forests. While previous studies focusing on local livelihoods reveal negative impacts of the FLA, particularly in the initial stage, studies on forest cover change as well as government statistics indicate positive changes in the longer term. We focused on micro-scale land use change after the FLA, and selected two upland villages with different accessibility in the Northeast region of Vietnam. Though the FLA was initiated in 1995 in both villages, the government reforestation program first reached Village G with paved road, and they did second planting. However, forestland recipients in Village A, with no paved road, also planted timber species as soon as the program was introduced. Though the mean allocated areas in Village A was larger than that of Village G, the mean of tree plantation areas was comparable, 1.39 ha (SE?=?1.09) in Village A and 1.38 ha (SE?=?1.01) in Village G. These results suggest that government support is a determinant of the timing and area of tree planting activities. After the FLA, one of the next policy challenges is how to make small-scale farm forestry financially independent.     

Colostrum quality,IgG absorption and daily weight gain of calves in small-scale dairy production systems in Southern Vietnam

Dairy production is expanding rapidly in Vietnam, but still, the smallholder farms are most common. The aim of this study was therefore to get improved knowledge about colostrum quality in dairy cows, immunoglobulin G (IgG) absorption, daily weight gain in dairy calves and calf management in small-scale dairy production systems in Southern Vietnam. A field survey was conducted on 40 farms, with two calves on each farm being intensively studied. It was observed that newborn calves were separated from their dams immediately after birth and offered 2–4 L first colostrum within 4 h by bucket feeding. The first colostrum IgG level, fat and protein content were on average 35.6, 4.8 and 21.4%, respectively, and 91% of the cows produced colostrum of good quality (Brix value >22%). The IgG level in serum of calves, measured as Brix value, was on average 9.3%. Colostrum in the samples studied was of quite high quality and on-farm observations showed that colostrum was offered on the first day of calf life, so passive transfer of immunity to the calves was high. In total, 10% of the calves had a Brix value for IgG in serum lower than 8.3%, indicating that those calves had suffered from failure of passive immune transfer (FPT). The daily weight gain of female and male calves was 0.75 and 0.54 kg, respectively. Serum IgG was positively correlated with colostrum protein (P = 0.002). Daily weight gain and diarrhoea was negatively correlated (P = 0.001).