Vol. 24 No. 9 (2026): Tạp chí Khoa học Nông nghiệp Việt Nam

This study was conducted to optimize the invitro propagation protocol of Anoectochilus lylei Rolfe ex Downie. A one-factor experiment was arranged in a completely randomized design with three replications. The results showed that: A double sterilization regime utilizing a 10% Ca(OCl)₂ solution for 10 minutes followed by a 3% H₂O₂ solution for 5 minutes was identified as the most optimal, resulting in a 98% survival and morphogenesis rate after 4 weeks of culture. The highest shoot cluster formation rate (81.33%) and the maximum number of shoots per cluster (6.25 shoots/cluster) were achieved on the MS medium supplemented with 20 g/l sucrose, 6.5 g/l agar, 30 ml/l coconut water, 2.0 mg/l BAP, and 0.1 mg/l IBA after 8 weeks. For in vitro shoot multiplication, the highest multiplication coefficient (15.75 shoots/explant) and an average shoot height of 3.35cm were recorded when the explants were cultured on the MS medium supplemented with 20 g/l sucrose, 6.5 g/l agar, 30 ml/l coconut water, 1.0 mg/l kinetin, and 1.0 mg/l IBA for 8 weeks. A 100% rooting rate, an average of 7.2 roots/shoot, and an average root length of 10.9cm were obtained on the optimal rooting medium consisting of MS + 6.5 g/l agar + 20 g/l sucrose + 0.7 g/l activated charcoal after 8 weeks. Finally, a survival rate of 100% was observed after 60 days of cultivation when in vitro plantlets were acclimatized in a nursery substrate mixture of alluvial soil, burnt rice husk, and farmyard manure (1:1:1 ratio) maintained at an 80-90% moisture content.

This study evaluated the physicochemical properties and methane production potential (BMP) of four organic by-products: feed waste, pig manure, chicken manure, and plant waste, through batch anaerobic fermentation over 42 days. The experiment was conducted using a laboratory BMP system. Performance indicators were calculated based on chemical oxygen demand (COD) and electrothermal production efficiency. The results showed that feed waste was the optimal feedstock with the highest accumulated CH4 yield (21,482NmL) and BMP (638,5ml CH4/g VS). Plant waste had a BMP of 513,5NmL CH4/g VS but a low COD conversion rate (7.01%) (half that of feed waste) due to its higher carbon content. Chicken manure had the highest solids content, while BMP was achieved at 346NmL CH4/g VS. Pig manure had the lowest BMP index, but its CH4 gas quality was superior, reaching 72.16% due to its high lipid content. The efficiency of electricity and heat production of the materials decreases gradually from food waste > chicken manure > plant waste > pig manure. The study confirms that the potential and quality of methane gas depend closely on the input materials, which form the basis for using these materials for biogas production and electricity generation in Vietnam.

This study was conducted to evaluate the composition, morphological characteristics, and association between intestinal protozoan infection intensity and digestive disorders in cultured frogs. A total of 219 frog samples collected from 19 farms showing reduced feeding, abdominal distension, and digestive disorders were examined for clinical signs, while intestinal samples were analysed using fresh wet mounts combined with Lugol’s iodine staining to determine the composition, prevalence, and infection intensity of protozoa. Protozoa were preliminarily identified based on morphology, motility patterns, ciliary distribution, and cytoplasmic characteristics. Protozoa were detected in 198/219 examined samples (90.4%), with three major groups identified as Balantidium spp., Nyctotherus spp., and Cepedea spp. Protozoan infection intensity varied considerably among surveyed farms, ranging from 21 to 664 protozoa per microscopic field. Common clinical signs observed in infected frogs included reduced feeding, abdominal distension, intestinal gas accumulation, and intestinal haemorrhage. Correlation analysis showed that total protozoan burden was positively associated with cumulative mortality and clinical severity in frogs (p < 0.001). The results suggest that excessive proliferation of intestinal protozoa may be closely associated with digestive disorders in cultured frogs under intensive farming conditions.

This study evaluated the effects of slaughter age on carcass yield and meat quality of Lac Son Ri chickens. The study was conducted from January to September 2025. A total of 1,000 Lac Son Ri chickens were raised under free-range conditions in Chi Thien commune, Hoa Binh province, and fed a complete commercial diet. Male chickens were slaughtered at 17; 19 and 21 weeks of age, while females were slaughtered at 15; 17 and 19 weeks of age. The results showed that thigh meat weight, by-product weight, abdominal fat weight, and abdominal fat percentage increased with slaughter age, reaching the highest values at 21 weeks of age in males (P

Infectious coryza (IC), caused by Avibacterium paragallinarum (A. paragallinarum), is highly contagious and persistent in treatment, causing significant economic losses due to reduced egg production in laying hens and slowed growth in broilers. This study aimed to isolate, serotype, and determine the antimicrobial resistance profile of A. paragallinarum from chicken. A total of 46 samples of nasal sinus and tracheal swabs were collected from laying hen farms suspected of IC infection to isolate A. Paragallinarum. The results showed that 24 samples (52.17%) were positive for A. paragallinarum. Among them, serovar A exhibited the highest detection rate (14/24; 58.33%), followed by serovar B (6/24; 25%) and serovar C (4/24; 16.67%). The isolates were highly resistant to tetracycline (MIC50 = 40 µg/ml, MIC90 = 64 µg/ml), erythromycin (MIC50 = 1 µg/ml; MIC90 = 4 µg/ml). In contrast, they showed low resistance to ceftiofur (MIC50 = 0.125 µg/ml; MIC90 = 1 µg/ml), gentamicin (MIC50 = 0.25 µg/ml; MIC90 = 2 µg/ml), and trimethoprim/sulfamethoxazole (MIC50 = 0.5 µg/ml; MIC90 = 2 µg/ml).

This study was conducted to evaluate the antibacterial activity of green chireta (Andrographis paniculata) - silver nanoparticles (green-synthesized silver nanoparticles) against Staphylococcus spp. isolated from cases of canine pyoderma. Among the 22 clinical specimens collected from 22 dogs with pyoderma, bacteria were isolated by culture on Mannitol Salt Agar (MSA) and identified using PCR. S. pseudintermedius was detected in 11 of 22 samples, corresponding to 50.0% of the cases. Agar diffusion assays demonstrated that the green-synthesized silver nanoparticles exhibited inhibitory effects against S. pseudintermedius isolates. The minimum bactericidal concentration (MBC) was determined to be 100 µg/ml, suggesting the potential of green silver nanoparticles as a supportive treatment for canine pyoderma.

This study was conducted to confirm the species identification of the small abalone (Haliotis diversicolor) using DNA markers combined with the analysis of key biological traits. Nine abalone samples from Co To, Bach Long Vi, and an F1 cultured stock were sequenced for the mitochondrial cytochrome c oxidase subunit I (COI) gene fragment for molecular identification. Simultaneously, the growth and reproductive characteristics of 930 individuals were monitored from September 2023 to August 2024. The results revealed that all specimens belonged to H. diversicolor, showing full congruence with the morphological identification. Morphological and biomass indicators displayed strong correlations, with the shell length-weight relationship reaching R2 = 0.981. The reproductive cycle exhibited seasonal variations, with sexual maturity peaking in autumn (September-October), as reflected by the highest values of the effective gonad volume (EGV) and gonad bulk index (GBI). Ultimately, the integrated DNA data and biological characteristics constitute a reliable scientific basis for broodstock selection, genetic management, optimization of seed production schedules, and species conservation in the coastal waters of the Gulf of Tonkin.

This study aimed to detect avian influenza A(H9N2) viral RNA in tissue specimens from clinically affected poultry, isolate the virus, and characterize selected biological features and experimental pathogenicity. A total of 55 lung, tracheal, and brain specimens were collected from 19 poultry at four farms in Hanoi, Hung Yen, and Thai Nguyen during 2020-2023. H9 and N2 RNA were detected by real-time RT-PCR, positive specimens were inoculated into embryonated chicken eggs and evaluated by hemagglutination (HA), hemagglutination inhibition (HI), and EID50 assays. H9N2 RNA was detected in 22/55 tissue specimens. Twelve specimens yielded hemagglutinating allantoic fluid, and seven isolates met the HI-based selection criteria and were passaged. Isolate H9N2.HY1.2 reached 8.89 × 107 EID50/ml and was used in an intravenous challenge model in 21-day-old chickens at 106 EID50/bird. No mortality occurred, mild clinical signs were most evident at 6-9 days post-inoculation. Viral RNA was detected in the trachea and lung through day 28, in the spleen and kidney through day 21, and in feces on days 7-14, but not in blood or pancreas. Lesions were observed mainly in the respiratory tract, with additional changes in selected extra-respiratory organs. These findings characterize H9N2.HY1.2 under an intravenous challenge model and should not be interpreted as population prevalence or as the course of natural infection.

This study evaluated the effects of different rootstocks on the growth, yield, fruit quality, and cadmium (Cd) accumulation of tomato plants grown in Cd-contaminated soil. A pot experiment was conducted in a greenhouse using cherry tomato cultivar ‘Thúy Hồng’ as the scion grafted onto three rootstocks: Vimina 1, Vimina 2, and eggplant EG203 under a Cd contamination level of 8 mg kg-1 soil. The results showed that rootstocks did not significantly affect plant growth or fruit yield, which ranged from 311.8 to 346.6 g/plant, but significantly influenced fruit quality and Cd distribution in the plant. Tomatoes grafted onto eggplant rootstock EG203 showed the highest fruit quality (vitamin C: 22.20 mg/100g, Brix: 7.30%, total sugars: 4.55%) and Cd concentration in fruits was lowest in this treatment (2.64mg kg-1). These results indicate that eggplant rootstock EG203 can reduce Cd accumulation in tomato fruits while maintaining yield and improving fruit quality, contributing to safer tomato production in Cd-contaminated soils.

This study was conducted to isolate and characterize bacteriocin-producing Enterococcus strains from freshwater fish, with the aim of applications in aquaculture. From 10 fish samples collected in Northern Vietnam, 36 lactic acid bacteria (LAB) strains were isolated. Among the isolates, strain E22 exhibited the highest inhibitory activity against Aeromonas hydrophila (12.69 ± 0.19mm). The antimicrobial substance produced by E22 demonstrated thermal stability from 60C to 100C, but its activity declined sharply at 121C and was completely lost after 30 minutes. The activity was completely eliminated upon treatment with proteinase K and trypsin, confirming the peptidic/proteinaceous nature of the compound. PCR analysis revealed that strain E22 carried the enterocin A gene exclusively. Furthermore, 16S rRNA gene sequence analysis showed 99.76% identity to Enterococcus lactis MHH, thereby identifying it as E. lactis E22.

Vietnam is a leading rice exporter in the world, contributing to global food security. However, the rice industry is facing many difficulties such as: global climate change, shrinking cultivated areas, and volatile prices. In response to this reality, the government has issued many policies to shift the export structure towards diversifying rice varieties and export markets. This study applied the Herfindahl-Hirschman Index (HHI) and collected data on Vietnam's rice exports from 2010 to 2024 to quantify the level of concentration (diversity) in rice exports. The results showed that Vietnam's rice export market was highly concentrated, with traditional markets such as ASEAN accounting for a large proportion, followed by other Asian markets and African markets. Export rice varieties were also highly concentrated, with white rice accounting for a large proportion; fragrant rice, although showing an increase in absolute value, showed a lower increase than white rice. Based on the findings, the article offers some recommendations for the sustainable development of Vietnam's rice exports in the future.

In Vietnam, access to energy is now nearly universal, yet affordability remains a substantive barrier. This study measures the energy expenditure burden-the share of spending on electricity, gas, firewood/rice husk, and natural gas in total household expenditure-and analyzes how this burden varies across living standards and ethnicity. The study assesses the regressivity of the burden across living standards, identifies the determinants of the burden and energy poverty, then clarifies ethnic disparities across burden levels. Using VHLSS 2024 data covering 9,399 households, the analysis applies OLS, Probit, and models interacting ethnicity with living standards. The results show a markedly regressive burden, declining from 12.23% among the poorest quintile to 7.19% among the richest; living standards are the strongest determinant, while small households, elderly households, and urban households are more vulnerable. Ethnic disparities emerge mainly in the tail of the distribution: compared with Kinh households, ethnic minority households face a higher probability of extreme burden, and their burden declines more slowly as living standards rise. The study recommends that energy price reforms be accompanied by targeted support mechanisms, and that policies for ethnic minority areas intervene on both the supply and demand sides.

This study aimed to review the factors influencing technology spillovers in animal feed manufacturers, with a particular emphasis on the mediating role of absorptive capacity. Based on a synthesis of theoretical perspectives and empirical evidence, five key groups of determinants were identified: (i) firms’ internal capabilities; (ii) industry network linkages; (iii) access to external technologies; (iv) competitive pressure; and (v) institutional and policy environment. Technology spillovers did not occur automatically but were closely dependent on firms’ knowledge base, organizational structures, and learning mechanisms. Within this process, absorptive capacity played a pivotal “bridge” role in transforming external knowledge into endogenous innovation capabilities. Accordingly, the study highlighted existing research gaps and suggested future directions that are particularly relevant to the context of Vietnam’s animal feed manufacturers.

The retail sector serves as an indispensable intermediary between manufacturers and consumers, facilitating the circulation of goods, enhancing shopping convenience, and optimizing the overall consumer experience. Nevertheless, customers' purchase intentions within this sector are shaped by a complex interplay of factors, particularly in the context of online shopping. Drawing on a bibliometric approach applied to 295 documents published between 2003 and 2026 retrieved from the Scopus database, this study employed VOSviewer and Biblioshiny to systematically map prevailing research trajectories. The findings revealed a marked surge in scholarly output in recent years, with growing attention directed toward benefit perception, psychological biases, consumer trust, and the transformative influence of technology on purchasing behavior. Citation network and co-authorship analyses further indicated a pronounced fragmentation of research across countries, alongside notable gaps in bridging psychological and technological determinants with purchase intention. The study proposed that future research should continue to explore the roles of artificial intelligence (AI), virtual reality, the metaverse, and the trust factor in online purchase intention within the retail sector in general, and the agricultural products and food sector in particular, in order to foster the sustainable development of the industry.