Vietnamese pangasius prices have become more volatile over the past decade exposing the business to risk and uncertainty. This study explored Vietnamese pangasius farmers’ perceptions about the sources of price risk and the effectiveness of price risk management strategies through Likert scales. The relationships between farm and farmer socioeconomic characteristics and their perceptions were also examined by using Chi-square analysis. Data were obtained through a structured survey with 110 farmers in three provinces of An Giang, Can Tho, and Dong Thap. Results suggested that pangasius farmers mostly concerned the instability of input prices, the volume of input supply, the instability of output prices, and the legislation of sales contracts between farmers and processors. We further found that price risk management strategies were not perceived as less effective measures to mitigate the price risk. Gender, farmers’ experience, farm size, crop period, farm types, and access to credit are positively related to the farmers’ perceptions. Findings on the price risk perceptions and management strategies are useful to support public and private of price risk management decision towards increasing the sustainability of pangasius production.

A study was conducted on Macrobrachium rosenbergii larvae to evaluate the efficiency of different diets to replace Artemia nauplii in the feeding scheme. The study included two experiments performed at pilot scale in 12–L tanks using a recirculating system. Larval stocking density was 100 larvae/L. After 7 days of feeding by Artemia nauplii, different diets, included wet and dry diets and decapsulated Artemia cysts, were tested to replace Artemia nauplii. An extra treatment using only decapsulated Artemia cysts throughout the complete larval rearing was also included. The results showed that feeding larvae exclusively decapsulated cysts for the complete rearing cycle was not appropriate. When gradually replacing up to 50% of the Artemia nauplii ration with wet or dry diets, good results in terms of growth, survival and quality of the larvae were obtained, similar to the control treatment receiving only Artemia nauplii. However, abruptly replacing 50% of the Artemia nauplii ration with artificial diets negatively affected larval development. Weaning could start from larval stage V, with about 25% of the Artemia nauplii replaced with artificial diet. Subsequently, the weaning ration could be increased up to 50% from stage IX to postlarva stage. Artificial diets should be provided in different particle size ranges based on the larval stage, gradually increasing from 250 to 1000 µm from stage V to postlarva stage. The results obtained in the present study may aid future research and serve as a baseline for further optimization of feeding strategies in prawn larviculture.

The experiment was conducted to determine the effects of four amino acids (lysine, methionine, threonine and tryptophan) supplementation on growth performances and serum antibody titers to Gumboro disease (IBD, infectious bursal disease) in broiler chickens. Chicks were randomly assigned to 5 dietary groups (5 chicks/group as 12 replicates of 5 chicks) in a complete randomised experimental design. Group I served as control group, was fed a diet without any supplementation. Groups II and III were supplemented 10% of four amino acids (lysine, methionine, threonine and tryptophan) of the recommended requirements for 45 and 42 days, respectively. Meanwhile, Groups IV and V were supplemented 20% of four amino acids (lysine, methionine, threonine and tryptophan) of the recommended requirements for 45 and 42 days, respectively. The supplementation was started at 3 days of age in chicks. The chickens were vaccinated against Gumboro disease at day 12 and day 19. The antibody titer of the chickens in each group was assayed using IBD anti-body ELISA. Besides, the live body weight, average feed intake and feed conversion (FCR) were determined at 0, 21, 42 and 84 days of age. The results showed no significant different between groups in performance parameters such as body weight and FCR. However, the present work showed highest dose of lysine, methionine, threonine and tryptophan supplementation for 42 days may be improved feed intake and immune response of chicken against Gumboro disease vaccination.

Rice is a staple cereal consumed by much of the world’s population but has received relatively little attention as a potential feedstuff for the animal industries in many parts of the world. It may be because its price is relatively high and only a small amount of rice produced is traded (6.2%). India, Thailand and Vietnam play a major role in the world rice export market. Rice is characterized by its high starch content, low fat and dietary fiber content, and lower crude protein content in comparison to other cereals. Rice-based diets have a higher apparent digestibility of nutrients than corn-based diets. Complete replacement of corn with rice in weaned pig diets does not affect growth performance, but feed efficiency is improved when corn is replaced with brown rice. Heat processing of rice does not influence digestibility and growth performance of pigs. Due to rice’s high digestibility and low fiber content, pigs fed rice-based diets have lower concentrations of volatile fatty acids and viscosity of intestinal digesta compared to other cereal-based diets. Moreover, rice has been shown to have potential to ameliorate diarrhea, colonization of pathogens, severity of enteric bacterial diseases, and pig removals. The mechanism for this protective function is not fully understood, but it may be, to a certain extent, related to lower fiber content and high digestibility of rice and a so-called “rice factor”. In practice, when availability and cost of rice permits, pork producers can benefit from the use of rice-based diets for piglets.

In recent years, the use of plants for clean-up and recovery (phytoremediation) has been studied and used in many countries of the world. In this study, E-Tian sweet sorghum (ET) and BT x 623 (BT) sorghum were treated with heavy metal cadmium at 5 concentrations (0, 5, 10, 25, 50 mg/kg). The growth of plant; absorption, accumulation of cadmium (Cd) heavy metals in plant parts at the seedling stage have been identified and assessed. The results showed that Cd affected the height and number of leaves of the plant. Especially, Cd accumulation in the plant decreased in sequence: root, stem, leaf. When comparing the heavy metals accumulation in the two cultivars, the results showed that the BT cultivar had higher Cd uptake and accumulation potential than ET. Therefore, BT can be used for phytoremediation of heavy metals in soil but not for providing food and feed.

The main objective of this study was to examine the efficacy and capacity of using hydroponic systems in municipal  pollutant removal at household scale. Three pilot scaled hydroponic systems [dimensionfor each system: 4.5 m (L) x Φ 114 mm] were installed to investigate the optimal age of vegetable, planting density and retention time for household wastewater treatment, respectively. Water spinach (Ipomoeaaquatica) planted in 27 plastic cups throughout 4.5-m-length and 114- mm-diameter uPVC pipes filled with wastewater was employed as the treating agent of pollutants. The averaged influent contained proximately 32.5 mg/L suspended solids (SS), 76.0 mg/L biological oxygen demand (BOD5), 220.5 mg/L chemical oxygen demand (COD), 26mg/L NH4+, 5.0 mg/L NO3−, and 8.5 mg/L PO43− at pH 7.3. Results showed that a designed system consisting of 10 plants of 15-day-old water spinach pre-planted in baked clay in each cup was capable oftreating 30 L of domestic wastewater meeting the current municipal wastewater discharge standards in Vietnam (column A standards of QCVN 14:2008/BTNMT) after 4 days of wastewater retention time. Ifoperated under conditions of the above parameters, the pilot-plant hydroponic system can achieve the removal of 65% SS, 82% BOD5, 74% COD, 90% NH4+, 30% NO3− and 86% PO43−. The result of this studyhas provided an applicable domestic wastewater treatment system ecofriendly and suitable for small and medium household areas.

The aim of this study was to isolate and optimize the growth conditions of thermophilic microorganism from hot springs. The isolation was conducted by using the mineral salt basal medium supplemented with 0.6% yeast extract at 500C. Totally, 33 isolates of thermophilic microorganism were isolated from hot springs at Truong Xuan (Khanh Hoa province) and Binh Chau (Ba Ria - Vung Tau province). The effects of temperature (45 - 800C), pH (pH 6 - 9) and carbon sources (malate, pyruvate, acetate, glucose, fructose, or carbon dioxide) on the growth of isolates were examined. In addition, the isolate morphology was also investigated by Gram and spore staining. The isolated thermophilic microorganism showed the diversity in colony morphology and color appearance. Most of them were rod shaped, spore-forming and most grew well at 500C and pH 7. The highest growth of all isolates was observed under malate, glucose, or fructose, as an organic carbon source and unable to use carbon dioxide. Six out of 33 thermophilic microorganism isolates (namely BM7, BS5, NS1, NS3, NS4, and NW6) grew rapidly under high temperatures from 50 - 550C and their morphology characteristics showed high similarity to Bacillus sp. The study evidenced the polymorphic diversity of thermophiles in the geothermal hot spring ecosystems.

Pouzolzia zeylanica is a kind of medicinal plant which is generally cultivated in Mekong Delta region. It owns many bioactive compounds that are known to possess antioxidant, antimicrobial and anticarcinogenic properties. This study aimed to optimize additional carrier concentration for spray drying of Pouzolzia zeylanica extract. Response Surface Methodology (RSM) with central composite design (CCD) was applied for optimization and investigation of the influence of maltodextrin (5÷15%, w/v) and carrageenan gum (0.06÷1.0%, w/v) concentration on the physicochemical characteristics of spray dried powder (bioactive compounds, moisture content as well as particle size distribution). The results showed that the optimum concentrations of maltodextrin and carrageenan gum were 8.8% w/v and 0.082% w/v, respectively. At these optimal conditions, the anthocyanin, flavonoid, polyphenol, tannin, moisture content and particle size of obtained spray dried powder were 5.77 mg cyanidin-3-glycoside equivalents (CE)/100 g; 29.49 mg quercetin equivalents (QE)/g; 28.35mg gallic acid equivalents (GAE)/g; 27.44 mg tannic acid equivalents (TAE)/g, 6.55% and 6.09 µm, respectively.

Acerola fruit is known to have a high vitamin C concentration. Polyphenolics are also natural oxidants occurring in plants. Understanding changes of these components during storage conditions and processing steps become important. Results of this research showed that there was significant difference in vitamin C and total polyphenolic concentration and three popular varieties of acerola fruits from Tien Giang province. Concentrations of both vitamin C and polyphenolics reduced rapidly during storage at room temperature. After three days, vitamin C reduced about 40% whereas total polyphenolics reduced about 70%. The losses at refrigerated temperature after 3 days were less than 15% and less than 30%, for vitamin C and total polyphenolics, respectively. Frozen storage of the fruit maintained quite well vitamin C and polyphenolics.Acerola pomace juice was concentrated before spray drying and, at the same vacuum pressure, temperatures influenced significantly the retention of vitamin C and total polyphenolics. Optimization of spray drying conditioners including inlet hot air temperatures and added ratio of maltodextrin (drying carrier) was also carried out to obtain high recovery of dry matter, total polyphenolics and vitamin C.

The aim of this study was to evaluate the antioxidant capacity of thawed frozen strawberries (Fragariaananasa) and mulberries (Morusnigra). Both types of fruit were frozen in a freezer with a cooling rate of 1 0 C/min and stored at -180C in 1 week before thawed at ambient temperature, cold temperature (40C) and in a microwave oven. ANOVA, LSD test and Principal Component Analysis (PCA) were applied to compare the effect of thawing methods. Results showed that different thawing methods significantly affected (P < 0.05) drip loss, vitamin C content, total phenolic content (TPC) and antioxidant capacity of strawberries and mulberries. The strongly negative correlation was found between the drip loss and the remaining vitamin C as well as between the thawing time and the antioxidant capacity of thawed fruit. Among three thawing methods, microwave was considered as the most effective method to retain antioxidant capacity, vitamin C and total phenolic content for both strawberry and mulberry.    

The Mekong Delta (MD) is of socio-economic importance for both Vietnam and Cambodia. The trans-boundary dimension and respective management issues are highly relevant for the economic development and security of each country. Because the economic development of each country is different in the boundary region of MD, there are many kinds of natural hazard occurred in MD (including flood, drought, acid sulphate soils, and saltwater intrusion), the impact of upstream development, a myriad of flood controlling infrastructure, and the implications of climate change. To resolve these above problems and maintain the boundary security condition, the two countries areimplementing many cooperation and coordination mechanisms (CMs) at central and provincial levels. In this article, the current CMs between the two countries are presented to clarify the implementing status, effective and coherent level of the trans-boundary water management (TWM). From that, some recommendations will be proposed to set up a new CM closed with TWM for the boundary provinces in MD.