Vol. 20 No. 4 (2022)

The extract from butterfly pea (Clitoria ternatea) flowers was done in ethanol 60% and methanol 50% and itsfractions were eluted byhexane: ethyl acetate with increasing polarity. Total efficiency of flower extraction in ethanol (17.01%) was higher thantotal extraction of the flowers in methanol (15.22%). Fraction 2 of the flowers extracted in methanol showed the highest total flavonoid content (621.43 ± 2.33mg QE/g extract). The highest total anthocyanin content in fraction 3 extracted in ethanol was 119.58 ± 1.19mgQE/g extract. The antioxidant activitiesof extract from butterfly pea flowers were investigated through its ability to reduce H2O2and free radical DPPH. The IC50value inhighfraction 3 of the extract in methanol was 166.29 ± 2.53 µg/ml and its ability to reduce H2O2was stronger than that of ascorbic acid at 176.23 ± 3.21 µg/ml. The IC50value in high fraction 2 and 3 of the flower extract in methanol was 589.27 ± 4.09 and 412.34 ± 2.91 µg/ml, respectively and all of these was able to deoxidize DPPH stronger than that of ascorbic acid at 656.23 ± 3.44 µg/ml. Thus, high fraction 3 with ethyl acetate eluent was suitable for the extraction of plant compounds from butterfly pea flowers with the strongest antioxidant activities. Furthermore, it is suggested that Clitoria ternateacan be used in dietary applications with a the potential to reduce oxidative stresses.

Identification of potential germplasms is the crucial step for selection and breeding program of passion fruit (Passiflora edulisSims.). In this study, genetic diversity and population structure of 31 exotic passion fruit accessions (including wild relative P. incarnata accessions) were assessed using sequence-related amplified polymorphism (SRAP) and inter simple sequence repeat (ISSR) markers. By primary screening for marker specificity and polymorphism, 8/15 SRAP markers and 10/18 ISSR were selected for passion fruit genotyping. The heterozygosity index H(0.43), polymorphic information content PIC(0.35), and discriminating power D(0.8) were recorded at a high level implying the significant genetic diversity of the analyzed passion fruit accessions. The Neighbor-Joining phylogenetic tree in combination with population structure model revealed by STRUCTURE discriminated and clustered the studied accessions into five groups which showed high accordance with the fruit color and the origin of the accessions. The analysis of melecular variance (AMOVA) also indicated the high rate of intraspecific and possibility interspecific hybridization among Passifloraspecies. These results provide essential genetic background facilitating efficient conservation and utilization of exotic passion fruit accessions in Vietnam.

The study aimed to determine the species diversity and composition of the benthic communities during the rainy season within the shrimp culture areas in Ca Mau province. The purpose of this study was to find the changes in species composition, and density distribution within the shrimp culture area as the basis for biological monitoring of the water quality in brackishwater shrimp farming areas. Benthic samples were collected at 9 sites in June and September, 2019. The results showed a total of 34 benthic species belonging to 31 genera, 24 families, 16 orders, 5 classes and 3 phylums. The number of species were variation among the sampling sites, from 2 to 11 species with a density ranged from 9 to 2,547 inds/m2. There were 23 benthos species identified during June, lower than those in September with 25 species. Additionally, the density of the zoobenthos in June were observed 2.5 times higher in comparison to those in September. The species composition and density of Gastropoda were highest within the study area. The similarity of the distribution of benthos was 18.9% at 9 sampling sites and divided into three groups. Shannon diversity index (H') ranged from 0.3 to 1.8, which indicated that the benthic diversity richness characterized by sampling location and time was low to moderate in the shrimp culture areas during rainy season.

This study was conducted to optimize the levels mixed herbal supplements in broilers diet for decreasing total cholesterol in blood plasma of chicken at 8 and 16 weeks of age. Six herbals supplements, garlic (Allium sativum), Chinese wedelia (Sphagneticola calendulacea), perilla (Perilla fruitescens var. crispa), turmeric (Curcuma longa), ginger (Zingiber officinale), and green tea (Camellia sinensis) were supplemented in the diet. A total of 126 male Dong Tao chickens were raised in animal farm of Vietnam National University of Agriculture from April 2021 to September 2021. This study was designed in two experiments: 1) Plackett-Burman matrix was designed to study the factors that affect total cholesterol content, 2) Response surface method (RSM) with central composite design (CCD) matrix was designed to optimize the levels mixed herbal supplements in diet. Garlic, turmeric, ginger, and green tea that have significantly contributed to total cholesterol in blood plasma was selected to design a matrix for modeling optimal point. The result of response surface method (RSM) with central composite design (CCD) showed the minimum value of total cholesterol 2.80 mmol/l (8 weeks of age) and 2.70 mmol/l (16 weeks of age) with level supplement of garlic (0.833 and 0.882 g/kg), turmeric (0.420 and 0.441 g/kg), ginger (1.411 and 5.400 g/kg), and green tea (5.221 and 6.215 g/kg), respectively. The lowest value of total cholesterol in the practical model was 2.80 mmol/l and 2.70 mmol/l.

The experiment on nursing the Yellowcheck (Elopichthys bambusa) from larvae to fingerling at different stocking densities and feeds was carried out from July to December 2020 at the National Freshwater Broodstock Center to determine the appropriate stocking densities and suitable feeds used in the nursering and rearing of larvae and fingerlings Yellowcheck. The results showed that the larvae reared at a density of 4-5 fish/liter gave a higher survival rate and growth rate than those nursed at a density of 6-7 fish/liter. The survival rate and growth rate of fish stocked at a density of 0.6 fish/liter were higher than those stocked at a density of 1 fish/liter and 1.2 fish/liter. Using 100% zooplankton and 60% zooplankton feed combined with 40% small worms for rearing fry gave the survival rate and growth rate higher than using feed consisting of 60% zooplankton with 40% fishmeal. In the period of rearing fingerlings, using larvae silver carp, small worms, and 30% small worms combined with 70% larvae silver carp, had a higher survival rate and growth rate than using feed containing 70% of larvae silver carp and 30% of larvae shrimp (45% protein).

This study was conducted to identify optimal diet for the growth of copepod population. The experiment was carried out in a completely randomized design (CRD) with 3 replicates in 250mL flasks. Copepods were provided with three different feeds: TreatmeNT1 (100% Nanochloropsis oculata), TreatmeNT2 (50% Nanochloropsis oculata + 50% Chaetoceros mulleri), TreatmeNT3 (100% Chaetoceros mulleri). The results showed that the treatmeNT2 had the highest density with 13.67 individuals/mL while the egg-carrying rate reached highest value in the treatmeNT3 with 0.42. The effect of different feeds on the body size of copepod was not significantly different (P >0.05)

This study aimed to evaluate the antibacterial potential of florfenicol and nanosilver combination for the treatment of bacterial infection caused by Aeromonas veronii in channel catfish. The susceptibility of A. veroniito nanosilver and the antibiotic florfenicol was evaluated in vitrovia measurement of inhibited zone based on the diffusion methods. The in vivoexperimental treatment was performed by challenging healthy Channel catfish at LD50 and by feeding with the supplement with different formulations of florfenicol and nanosilver. The results of in vitroexperiments showed that the combination of 10ppm florfenicol and 5ppm nanosilver resulted in the inhibited zone comparable to that of conventional use of antibioticflorfenicol (15ppm). After 7 days of treatment, the combination of florfenicol and nanosilver antibiotics had a similar therapeutic effect compared to those using antibiotics alone.

Land use changes are recognized as one of the most significant driving forces of environmental changes. This study aimed to predict land-use change in Don Duong district, Lam Dong provinceby applying the integration of GIS, Markov chain and logistic regression. The land-use maps of 2010 and 2015 were employed to predict the land-use scenario for 2020. The predicted results were compared with the observed land-use map of 2020 to validate the method using kappa index statistics. Based on the proposed model, the future land-use change prediction for 2025 and 2030 was performed. The forecast results show that Don Duong district had a significant change in land use. Converting the forest land into other land uses, especially to built-up land and annual agricultural land, is the main land-use change in the future.The resultof this study providesuseful information as the foundation for planning local land-use policies to ensure sustainable development goals.

This study aimed to assess climate change vulnerability at the district level in Son La province. Vulnerability was definedbased on IPCC's conceptual framework, in which vulnerability is a function of components of exposure, sensitivity and adaptability. A total of 32 indicators belonging to these three components were selected and given weights based on the method of hierarchical analysis. The values ​​of these indicators werecollected based on secondary data. Research results showedthat 5 out of 12 districts of Son La province werevulnerable to climate change at a high to very high levels. In which, Phu Yen district wasthe most vulnerable due to its both very high exposure and susceptibility to climate change, while its adaptability wasonly moderate. Son La city and Moc Chau district werethe lowest vulnerable to climate change.Factors that influence vulnerability were also identifiedThese results have implications for policy makers in developing appropriate and effective climate change adaptation strategies for Son La province.

This study was conducted to analyze the factors affecting the technical efficiency of duck farming in the coastal area of the Red River Delta.Thestudy appliedthe stochastic production frontierto estimate technical efficiency and usedsurvey data of duck farmers in 3 coastal provinces (Thai Binh, Hai Phong,andNinh Binh). The results showedthat the average economic efficiency in duck production was quite high, at 74.72% for domestic duck farmingand 97.8% for sea duck farming.The factors that hadpositive impact on the economic efficiency of duck farmingincludedage, experience, education, and association activities. We recommend that policymakers canusethe findings from this study to help farmers expanding the scale of sea duck production in the future.

This study was conducted to analyze the factors affecting the technical efficiency of duck farming in the coastal area of the Red River Delta.Thestudy appliedthe stochastic production frontierto estimate technical efficiency and usedsurvey data of duck farmers in 3 coastal provinces (Thai Binh, Hai Phong,andNinh Binh). The results showedthat the average economic efficiency in duck production was quite high, at 74.72% for domestic duck farmingand 97.8% for sea duck farming.The factors that hadpositive impact on the economic efficiency of duck farmingincludedage, experience, education, and association activities. We recommend that policymakers canusethe findings from this study to help farmers expanding the scale of sea duck production in the future.

This study aimed to reflect the performance of applying environmental cost management accounting (ECMA) at domestic animal feed production enterprises in Vietnam. Descriptive statistics technique was applied to describe the situation and implementation level of ECMA in 102 surveyed enterprises. Anova analysis was also used to compare and test the difference in the level of implementation of ECMA among enterprises which had different production scale. The research results showed that the environmental costs identified in domestic animal feed production enterprises included the cost of waste treatment, the cost of environmental management and prevention, and the cost of non-product output. However, there were very few enterprises that kept track of environmental costs on their own accounts and most of them did not establish norms and separately estimate environmental costs. Especially, none of enterprises had separate environmental costs reports; rather these costs were intergrated in the other expenses reports. Some recommendations animal feed production enterprises to compelete ECMA were proposed.

The present research analyzed the impact of the structure and the conduct on the market efficiency to develop a stable market for cobia fish farming households in Nghia Hung district, Nam Dinh province. The study used 217 samples with direct interview method and the data collected were analyzed by structural equation modelling (SEM) to evaluate the strength of the relationship between the structure, the conduct and the market efficiency. Research results showed that structural factors and market conduct positively affected market efficiency, but the cost factor exerted no influence on the fisheries policy. The findings showed that the competitive advantage factor had the strongest impact on fisheries policy factor (0.414), followed by and material input (0.345). The industry competition factor had the biggest influence on quality assurance factor (0.145) while the quality assurance factor (0.353) exerted positive impact on improving market efficiency and developing a stable market. Some solutions to promote these factors were proposed.

The development of Vietnam’s economy is under pressure due to the rising level of environmentalpollution. This problem showed that it is crucial to change behavior in both production and consumption to move towards a green economy. Based on the previous researches, thispapersynthesized some theoretical issuesrelated togreen consumptionbehavior and overviewed the Vietnam’s situation of green consumption. Definition of green consumption behavior was developed from the concepts of consumption behavior and green product. The factors affecting green consumption behavior shown in the previous studies could be classified under two broad categories: individual and situational. Although, the conclusions about their impact on green consumption behavior show certain similarities, they were not completely identical. Green consumption in Vietnam has received the society’s concerns but has stillfacedsome obstacles related to habits and resources.