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Artemia parthenogenetica is an emerging species used in marine hatcheries in Vietnam. Disinfection during their cyst incubation is important, however, disinfectants might have side-effects. This study examined the effects of polyvinylpyrrolidone coated nanosilver particles (AgNPs) on A. parthenogenetica cyst hatching and nauplii development. Cysts were exposed to low (0.1, 0.4, 0.7 mg/L) and high (1, 4, and 7 mg/L) levels of AgNPs for 48h. The total Vibrio in incubated water and nauplii significantly decreased when AgNPs were applied, however, the hatching success significantly reduced when the AgNPs level exceeded 1 mg/L. Nauplii instar I and instar II were exposed to 10; 50; 100; 200; 500; 600; 700; 750; 800; 900 and 1000 mg/L to determine their LD50. The LD50-36h and LD50-48h of AgNP on Instar I were 136.5 and 53.21 mg/L while those on Instar II were 22.15 and 12.1 mg/L.    

Flavobacterium oreochromis is a major bacterial pathogen that causes columnaris disease in tilapia (Oreochromis spp.) and other freshwater fish species. assessed the antibiotic resistance profiles and minimum inhibitory concentrations (MICs) of F. oreochromis isolates obtained from infected tilapia cultured in Northern Vietnam. A total of 51 isolates retrieved from diseased fish collected in Hai Duong (n=23), Bac Ninh (n=16), and Hoa Binh (12 isolates) were used in the study. The bacteria were cultured on TYES agar, identified through morphological and biochemical analyses, and confirmed by PCR. Antimicrobial susceptibility testing employed the disk diffusion method against 16 antibiotics, while MICs of six frequently used antibiotics were determined via the broth microdilution method. The antimicrobial susceptibility test revealed that isolates exhibited high resistance to oxacillin (100%) and neomycin (76.5%),  moderate resistance to sulfamethoxazole-trimethoprim (37.3%), doxycycline (35.3%), and oxytetracycline (41.2%). Resistance to the remaining antibiotics was below 12%. Notably, all isolates were multidrug-resistant (MDR), exhibiting resistance to 2–10 antibiotics and 14 distinct resistance phenotypes were identified. MIC values ranged from 0.063 to 1 µg/ml for amoxicillin, 0.125–8 µg/ml for erythromycin, and 0.25–8 µg/ml for florfenicol. For oxytetracycline, doxycycline, and sulfamethoxazole-trimethoprim, MICs ranged from 0.016–1 µg/ml, 0.125–2 µg/ml, and 0.5–16 µg/ml, respectively. These findings highlight a decline in the efficacy of commonly used antibiotics against F. oreochromis, underscoring the necessity for routine antimicrobial susceptibility testing to promote rational antibiotic use in aquaculture.

The objective of this study was to determine the effects of 2,4-Dichlorophenoxyacetic acid (2,4-D) combined with 6-Benzylaminopurine (BAP) and sucrose on the shoot and root regeneration of Paph. micranthum var. North Vietnam. Young fresh leaves were cut into small explants and then cultured on media containing 2,4-D (0.5, 1.0, or 2.0 ppm). Within each of the 2,4-D concentration, BAP was added at three different concentrations (0.5, 1.0, or 2.0 ppm) for callus induction after 4 weeks. Shoot tips (2-3 mm in length) from the leaf-derived calluses were then transferred vertically on half-strength MS medium (2,4-D combined with BAP (0.5, 1.0, or 2.0 ppm) for shooting, and rootless shoots with 2 leaves were transferred to the same MS medium for rooting after 4 months of culture. Rootless shoots with 2 leaves were also transferred vertically on half-strength MS medium with different sucrose concentrations (0, 10, 20, 30, or 40 g L-1) to optimize the growth and development of the plantlets. The results indicated that the optimum degree of shoot and root regeneration occurred on half-strength MS medium containing 2.0 ppm 2,4-D combined with 2.0 ppm BAP. Approximately 86.6% of the cultures responded with 3.3 shoots and 3.0 leaves/explant. In addition, under the optimal concentrations, the number and length of roots per explant after 4 months of culture were 2.1 roots per explant and an average root length of 1.1 cm. MS medium supplemented with 30 g L-1 sucrose had the highest number of leaves and roots, and also the longest average length of roots, which gave 3.8 leaves, 3.3 roots/explant, and a root length of 1.8 cm after 4 months.

The objectives of this study were to evaluate the effects of nitrogen forms on root system development (expressed as total root length, nodal root number, nodal root length, and lateral root length), water use, photosynthetic rate, and dry matter production under water deficit (WD) at 20% w/w and continuously waterlogged (CWL) conditions. Rice plants cv. Nipponbare were grown in plastic pots in a vinyl house. Six N forms were applied at the same rate of 360 mg N per pot, and were prepared as follows: N-NH4+ alone (A); N-NH4+ with nitrification inhibitor (A+DCD); N-NO3- alone (N); N-NO3- with nitrification inhibitor (N+DCD); combined N-NH4+ and N-NO3- (AN); and combined N-NH4+ and N-NO3- with nitrification inhibitor (AN+DCD). The nitrification inhibitor, dicyandiamide (DCD) (C2H4N4), was applied at the rate of 100 mg pot-1. The results of the experiment showed that under both WD and CWL conditions, significant increases were seen in the root system development as expressed through total root length, nodal root number, nodal root length, and lateral root length in the N-NO3- treatments with and without DCD compared to the application of N-NH4+ treatments with and without DCD. This led to an increase in water use, and eventually a significant increase in dry matter production. Similarly, the A treatments with and without DCD also significantly increased root system development as compared with the AN and AN+DCD treatments. Furthermore, under both CWL and WD conditions, the positive and notably significant correlations between the total root length and water use, as well as between the total root length and shoot dry weight, were found only in the A and A+DCD treatments. These results indicate that rice prefers sole ammonium over the mixed ammonium-nitrate treatment, and sole nitrate applications under both WD and CWL conditions.

Mineral nutrients are essential to plant growth and development. The present study aimed to evaluate the effects of mineral fertilizer doses and N:P:K ratio on growth, yield, and raw material quality of the tea variety PH10 to improve the production of high-quality tea products. The field experiment was conducted from 2015 to 2017. A two-factor experiment was designed by pplit-plot design with three replications. The mainplot treatments were three fertilizer doses of N  for one metric ton of fresh shoot products (30, 40, and 50 kg N ha-1). The subplot treatments were two NPK ratios (3:1:1 and 3:1:2). Plant height, leaf canopy, plant diameter, shoot yield parameters, shoot components, biochemical compounds, and sensory quality for Oolong and Sencha tea products were evaluated. The results showed that increasing fertilizer doses improved remarkably growth, yield, and made tea quality of PH10 variety up to 40 kg N ton-1. Different fertilizer ratios resulted in variations in plant growth, the content of carbohydrate, sensory quality for taste and flavor as well as total sensory quality with higher values at NPK ratio of 3:1:2. Applying mineral fertilizer with an NPK ratio of 3:1:2 and  40 kg N per ton of fresh shoot products was recommended to bring about the most benefits of tea yield and quality as well as economic profit.  

Probiotics and prebiotics are increasingly encouraged in aquaculture to reduce antibiotic use. The present study aimed to investigate the effects of dietary supplementation of peptidoglycan or Lactobacillus plantarum or its combination on the growth performance, disease resistance, and immune status of striped catfish juvenile. Fish were fed on the commercial feed supplemented with various concentrations of peptidoglycan and Lactobacillus plantarum at 0, 5, 5, 2.5 + 2.5, and 5.0 + 5.0 per kg of feed, named to PP0.0, PG5.0, LP5.0, PP2.5, and PP5.0 treatments. Fish were then fed at a ration of 3% of fish body weight for 6 weeks. After feeding trial, fish were infected with Aeromonas veronii at 50% lethal dose (LD50, 107 CFU/mL). Blood samples were collected after 2, 4, and 6 weeks of experiment (T2, T4, and T6) and at second day after bacterial infection for hematological parameters and immune assays. The results demonstrated that supplementation with PP2.5 significantly improved growth performance and feed utilization in fish, while the LP5.0-based diet reduced mortality in A.veronii-challenged fish, indicating enhanced disease resistance. The modifications in hematology and immune status were affected by pro-, pre-, and synbiotics tested in this study. In conclusion, dietary supplementation with peptidoglycan and L.plantarum enhances growth, immunity, and disease resistance in striped catfish, supporting sustainable aquaculture practices for improved fish health and production efficiency. 

Cryptocaryon irritans is an ectoparasitic protozoan responsible for white spot disease posing a significant threat to mariculture systems in Vietnam. This study aimed to isolate and propagate C. irritans, and to establish an experimental infection model in Trachinotus spp. (5-7 cm in lengh) under laboratory conditions. Between February and June 2025, a total of 106 fish samples were sourced from aquaculture operations in Quang Ninh and Khanh Hoa, revealing an average C. irritans infection rate of 59.43%, with the highest prevalence observed during March and April. Infected fish exhibited clinical signs including skin darkening, mucus loss, white spots on skin and gills, fin erosion, ulcerations, and tissue damage. The parasite was successfully cultured at the trophont stage and was propagated to the tomont and theront stages at 28-30°C, achieving a conversion efficiency of 61.7% after 48 hours and yielding an average of 150-300 theronts per tomont. These theronts introduced to Trachinotus spp. at a density of 5,000 theronts per 250L tank (50 fish) at a temperature of 28°C. The infection progressed rapidly, with trophont emergence observed within 2-3 days and complete mortality by day 7. The established infection model offers a robust platform for further research in epidemiology, immunology, and therapeutic interventions against C. irritans.

Coastal aquaculture zones, including areas for shrimp and mollusk farming, are subject to multiple stressors, such as internal farming activities, inland runoff, and extreme weather events driven by climate change. These factors contribute to spatiotemporal fluctuations in water quality, directly affecting aquaculture productivity and sustainability. This study aims to assess the current status of water quality in shrimp and clam farming areas across coastal districts of Nam Dinh Province, Vietnam, identify spatial and temporal variation trends, and propose appropriate management measures. Environmental parameters, including pH, dissolved oxygen (DO), salinity, alkalinity, COD, ammonium (N-NH₄⁺), nitrite (N-NO₂⁻), hydrogen sulfide (H₂S), total suspended solids (TSS), and total vibrio count, were monitored biweekly. The results indicated significant temporal fluctuations in water quality, with a clear deterioration trend during the rainy season and in storm-affected months, particularly in September, during the passage of Typhoon Yagi. In shrimp farming areas, water source quality tended to decline during June–August. Localized differences were also observed: Nghia Hung was characterized by low DO levels, while Hai Hau experienced large salinity fluctuations. In clam farming zones, water quality was lowest in June and July. Giao Thuy exhibited a higher frequency of salinity values falling below acceptable thresholds compared to Nghia Hung, suggesting greater variability in salinity levels. These findings provide a scientific basis for local authorities and farmers to plan adaptive water management strategies, such as storing high-quality water for use during periods of environmental stress.  

Spotted sea bass (Lateolabrax maculatus, McClelland, 1844) is a species belonging to the genus Lateolabrax (Lateolabracidae), and is characterized by the many distinct black spots on the bodies of mature fish. For the first time, six specimens have been recorded in Quang Ninh province. The specimens were collected from Luon Cave in Bai Tu Long National Park in May-June 2019. The new specimens collected from Quang Ninh, Vietnam are different from the recorded specimens from Japan, Korea, Taiwan, and China in terms of lateral line scales (LLS) as the samples collected in Quang Ninh, Vietnam have 94-97 scales and the samples collected from the other countries have 66-82 scales. Phylogenetic analysis of the 16S rDNA sequence confirmed that all of the samples collected in Quang Ninh, Vietnam belonged to the species of spotted sea bass.

Agricultural field wastes contain a large amount of active chemicals in the form of pesticide residues. However, treatment of these active chemicals is still weak since a more complex process is required. This study aimed to extract pesticide residues from field waste bags using baking soda (NaHCO3), acetic acid (CH3COOH), and a cleaning solution, and then remove the pesticides from the wastewater by the photo-Fenton reaction. The pesticide bags were collected from intensive paddy fields in Hanoi. The research was conducted on samples of selected fungicides, insecticides, and herbicides. The results showed that a 1% NaHCO3 solution had an optimal extraction performance and obtained a high rate of COD after 15 minutes of exposure, followed by CH3COOH and the cleaning solvent. The extraction process under the photo-Fenton reaction was enhanced by circulation (25 liters per min) and aeration (60 liters per minute). It was found that alanine, carbaryl, and carbamate were in the extracted solutions. The removal efficiency by the photo-Fenton reactions with 254nm UV light at pH around 3.0 increased from 64% to 92% for these residues when the ratio of Fe2+/H2O2 increased from 1:5 to 1:15. This study shows a potential pesticide treatment from field waste bags by photo-Fenton reactions to reduce negative impacts on the environment and ecosystem.

The ftsZ proteins have been well-characterized to play a crucial role in the cell division. Here, we reported a comprehensive analysis of the ftsZ proteins in Bacillus and Lactococcus genus groups by the bioinformatics approaches. As the results, we identified and characterized ftsZ proteins in 19 Bacillus and 22 Lactococcus species. The sizes and weights of the ftsZ proteins in Bacillus and Lactococcus genus groups ranged from 376 to 410 aa residues, 387 to 430 aa residues, and from 39.53 to 44.15 kDa, 41.14 to 45.11 kDa, respectively. All ftsZ proteins in Bacillus and Lactococcus species were acidic and globular and localized in the cytoplasm. Next, the 3D model and multiple alignments have been performed. We realized that the ftsZ proteins in Bacillus and Lactococcus species exhibited five specific regions. Taken together, our study could provide a general background for further functional characterization of the ftsZ proteins in Bacillus and Lactococcus species.

The research focused on evaluating the economic efficiency of swine farms applying biosecurity practices in Bac Ninh Province. Our study surveyed 143 pig farms in Bac Ninh province. The ordinal logit regression model was employed to estimate the factors affecting the level of biosecurity practices. Moreover, the semi-log regression model was used to examine the influence of some factors affecting the profitability of pig farms. The results showed that biosecurity practices had a significant impact on the economic efficiency of livestock farms by helping livestock farms increase their economic efficiency, reducing the mortality rate of animals, and reducing the rate of abandonment of farms.  The factors affecting the level of biosecurity application on the farms included the gender, experience, and education of the farm owner, and the livestock scale. The results aslo expressed a negative relationship between the economic efficiency of the farm and seeding costs, electricity and water costs, feeding costs, labor costs, and veterinary medicine costs, and a positive relationship between the economic efficiency and selling price as well as between the livestock scale and biosecurity application. Finally, some appropriated solutions could be recommended for the improvement of the economic efficiency of swine farms applying biosecurity practices.