Vol. 22 No. 2 (2024)

This study aims to determine the most suitable artificial diet for rearing the Oriental fruit fly Bactrocera dorsalis. The experiment was conducted by evaluating the growth and development parameters of the Oriental fruit fly when reared in the laboratory with four artificial diets with main ingredient: yeast (TA1), wheat bran (TA2), rice bran (TA3), and ground longan (TA4). The results showed that B. dorsalisfemales reared on TA2 had the shortest lifecycle (29.75 days), while there was no significant difference in lifecycle when reared on the three other diets, with 34.23 days (TA1), 34.28 days (TA3) and 34.27 days (TA4). The daily oviposition and total reproduction of the female adults reared on TA2 were the highest, with values of 13.11 eggs/day and 587.40 eggs/female, respectively, significantly higher than the other diets. The net reproductive rate (R0) and intrinsic rate of increase (rm) were also significantly higher than the other diets. R0decreased in the order of TA2 (320.73), TA3 (264.55), TA1 (262.63), TA4 (258.78), while rmdecreased in the order of TA2 (0.131), TA1 (0.120), TA3 (0.116), TA4 (0.115). In conclusion, the diet with wheat bran as the main ingredient (TA2) proved to be the most suitable for the development, reproduction, and mass rearing of the Oriental fruit fly.

The study aimed to evaluate the growth, potentials of biomass, and seed yields of 40 s introduced sunflower accessions. The experiment was conducted in the Spring cropping season of 2023 at Gia Lam, Hanoi in a non-replicated field experiment. The result showed that the potential accessions for biomass yield belonged to medium and late maturity groups. Biomass yield had a positive correlation with leaf area. Seed yield correlated negatively with the number of heads/plant, and positively with head diameter, total seed numbers/head, and 1000-seed weight. The accessions “CA sunflower” (87.5 tons/ha), “Red Sun” (83.1 tons/ha), and “Roshia” (77.3 tons/ha) had higher biomass yield compared to the control “Aguara” 6 (76.3 tons/ha). “Sono” accession had a high biomass yield (73.9 tons/ha) and the highest seed yield (6.54 tons/ha).

Butterfly ginger lily belongs to the Hedychium genus including 80 species, and is one of the important and popular genera of the Ginger family (Zingiberaceae). It has both medicinal and horticultural uses. The research aimed at studying the possibility of asexual propagation of butterfly ginger lily by aerial stem cuttings contributing a new propagation method for Butterfly ginger lily in particular as well as for other plants in generally. The experiment on propagation media and aerial stem cutting type of butterfly ginger lily were arranged in a randomized block design with three replications. The results showed that the medium containing smooked rice husk : sand (1: 1 in volume) and aerial stem cuttings with 2 nodes were the most suitable for asexual propagation of butterfly ginger lily by aerial stem with sprouting time of 10 days after planting and shoots reaching 20.2cm in length, 0.74cm in diameter, with7.8 leaves/shoot and 7.4 roots/shoot and roots of 7.0cm long.

The purpose of this study was to identify Salmonella typhimurium (S.typhimurium), causing salmonellosis in layer ducks farmed in Phung Thuong commune, Phuc Tho, Ha Noi. A total of 32 farm households were selected based on farm-scale and breeding method. Forty-four salmonelosis-suspected ducks were necropsied to monitor gross lessions; of which, 33 ducks had gross lessions of the disease. We collected livers (15 samples), spleens(11 samples), and ovary (7 samples) from 33 ducks with gross lession of the disease, besides, irregular egg yolks (15) were collected for bacteria isolation and then typing by PCRmethod. Results indicated that liver samples had the highest percentage of positive samples (60.0%), followed by spleen (54.5%), ovary (42.9%) and the lowest was the irregular egg yolk sample (40.0%). Twenty-four S.typhimurium strains were isolated and detected by PCR method. Testing the antibiotic sensitivity of the S.typhimurium isolates showed that thesestrains were most susceptible to colistin(100%), followed by doxycycline (79.2%) and gentamicin (70.8%) but moderately sensitvie or resistant to amoxicillin, ampicillinand neomycin.

The study was conducted at a pig farm in Van Lam district, Hung Yen province from August 2021 to November 2022 to evaluate the growth performance and carcass traits of D×(DLY) fattening pigs born from Duroc×(Landrace×Yorkshire) survivor sows infected African swine fever virus and Duroc boars. A total of 110 pigs (61 females and 49 barrows) were recorded from birth to the end of the experiment at 223.36±14.78 (± SD) days of age. Pig was individually tattooed at birth and ear tag at weaning. The body weight of each individual was weighed at birth and weaning. Back fat thickness (BFT), longgissimus muscle depth, loinmuscle area, intramuscular fat (IMF) and lean meat percentage (LMP) were determined by ultrasound on live pigs at the same time of weighing body weight at the end of the experiment. The results showed that the finishing weight (132.40kg), average daily gain (640.55g) in barrows tended to be higher (P = 0.074 and P = 0.057) than those in female pigs (126.60kg and 608.75g). BFT, IMF in barrows were significantly higher than female pigs (P <0.01) but LMP was lower (P <0.001) and were 16.49 and 13.41mm; 2.54 and 2.19%; 57.63 and 61.03% respectively. D×(DLY) can be used as fattening pigs with carcass traits similar to normal pigs but with lower weight gain.

This study was conducted to determine the growth performance and meat quality of Cay Cum broiler chicken raised at the Indigenous plant and animal research and development branch - Mountainous mining company in Tuc Tranh commune, Phu Luong district, Thai Nguyen provincefrom April to December 2021. A total of 450 Cay Cum broiler chickens were raised in three lots. Three experiment groups were kept with the same animal production and disease prevention procedure of the National Institute of Animal Husbandry. The weight of chickens individuals from pens was recorded weekly for performance assessment. At 16 weeks of age, a total of 6 chickens (3 male, 3 female) were randomly selected for slaughter to evaluate productivity and meat quality. The results showed that Cay Cum broiler chickens had a high survival rate (92.44%), and the body weight of sixteen-week-old chickens was 1,484.50g. Cay Cum chickens consumed 49.92 grams of feed per day and FCR was 3.57kg of feed per kilogram of the chicken body weight. This chickens had the meat quality index within the normal range value of Vietnamese domestic chickens. The percentage of carcass of male and female chickens were 71.21% and 70.89%, respectively whiel the percentage of thigh meat from 19.39 to 20.75% and the breast meat from 16.09 to 17.33%, respctively. The toughness of thigh meat was higher than that of breast meat and the figure in males was higher than in females.

The study was conducted to evaluate the distribution and diversity of zoobenthos species composition at integrated shrimp-mangrove farms in Ca Mau province. The sampling was taken monthly during 12 months, from January to December 2022. At each sampling, samples of zoobenthos were collected in 9 farms (3 farms/district) in three districts of Ca Mau province, including Dam Doi, Nam Can, Ngoc Hien. A total of 49 species were identified and they belonged to 43 genera, 4 classes and 3 phylums, including Molluscan, Annelida and Arthropods. The molluscan community was the most pre-dominant (28 species), followed by Annelida (15 species) and Arthropods (6 species). The number of mollusca species was higher than those of the others. Total zoobenthos abundance in each point varied from 16 to 30 species, with the mean ranging from 119 to 2,833 ind./m2. The species composition and abundance of Gastropoda were highest within the study area. The Gastropoda represented the highest number ranging from 2-15 species and density from 2-2,794 ind./m2in the study area. The shannon (H’) diversity index ranged from 0.6~1.4, indicating that the diversity richness of zoobenthos characterized by sampling sites and periods was low to moderate level. The species diversity of zoobenthos in Nam Can area was considerably lower compared to that in Dam Doi and Ngoc Hien areas..

The study was conducted to establish, optimize and validate the real-time PCR assay for the detection of Decapod iridescent virus 1(DIV1) and control of this disease in shrimp. The plasmid samples containing two target genes MCP and ATPase of DIV1 were used to establish and optimize the procedure using different probe concentrations 0.1, 0.15 and 0.2µM. The sensitivity, performance, specificity, inter-assay stability, and interlaboratory matching results from nationally and internationally standardized laboratories were used to evaluate the efficacy and validity of these real-time PCR assays. The results of real-time PCR using plasmids containing target MCP and ATPase genes at a probe concentration of 0.2µM revealed the best detection ability. The reaction detection limits were 13.6 and 14.3 plasmid copies/reaction with the efficiency at 98.9% and 92.6%, respectively. The assays exhibited high specificity (no reaction to all shrimp-positive samples for WSSV, IHHNV, AHPND, and EHP) and high stability (CV < 15%). The study results showed that two real-time PCR assays using plasmids carrying target MCP and ATPase genes of DIV1 established in this study could ensure reliability and applicability to laboratories for screening and controlling DIV1 disease in Vietnam.

The objective of this study was to identify and evaluate factors influencing land use changes in Hung Yen province. The data were analyzed using descriptive statistics, correlation analysis, exploratory factor analysis, and regression analysis. Results from the investigation of land use status show that in Hung Yen province, there were 3 types of land that changed tremendously during 10-year period (2012-2022), including rice land, perennial cropland, and construction land. The study has identified 04 main factors influencing land use changes in the province, i.e. (i) State policy on land use management, (ii) Economy, (iii) Infrastructure development and (iv) Location. In particular, the State's policy on land use management factor exerted the greatest impact on land use changes in Hung Yen province. The finding of the study is an important practical basis for local authorities on orientations in the process of rational land use and sustainable protection of land resources.

The main goal of study was to use nucleotide sequencing of the cytochrome c oxidase 1 (COI) gene to assess the genetic diversity of 9 bivoltine breeds and 5 native Vietnamese silkworm breeds. DNA Sequencing was carried out using by chain termination method. Data were analyzed by Bioedit, DNAsp and MEGA X softwareThe results indicated 17 polymorphic nucleotide substitution sites when comparing the COI gene sequence of the 14 silkworm breeds in this study with the sequence AB737913.1 on GenBank. Only one polymorphic nucleotide site appeared when comparing the 14 breeds with each other. These silkworm breeds were divided into 2 haplotypes, with a main concentration in haplotype 1. The genetic classification tree shows that 13 out of the 14 studied silkworm breeds were distributed in branch 2, which is the common branch of Chinese and European silkworm breeds. This outcome provides initial information for breeders to strategically use molecular markers in the conservation, exploitation, and development of the genetic resources of silkworm.

Alternarialeaf spot on cucumber causes serious damage to marketable fruit yield and quality. The study was carried out to select bacterial strains from the cucumber rhizosphere soil with antagonistic activity against Alternariaalternata. The isolates were evaluated for their antifungal activity by dual culture method. The antagonistic isolates were investigated for their ability to produce hydrolytic enzymes and siderophore. The antifungal activity of volatile organic compounds was evaluated by the Petri dish inversion method. Twelve isolates exhibited antagonism against A. alternata. Growth inhibition of A. alternataby these isolates ranged from 9.7 to 47.8%. Eight isolates showed the ability to produce siderophore. All isolates were capable of producing hydrolytic enzymes (β-1,3-glucanase, chitinase, protease). Chitinase had a strong correlation with the ability to inhibit the growth of the pathogenic fungus (P <0.05). Volatile organic compounds of 12 antagonistic strains showed the ability to inhibit the growth of spores (61.8-95.2%) and mycelium (58.9-79.7%) of A. alternataThe results of this study indicated the potential of rhizobacteria in controlling A. alternatacausing leaf spot in cucumbers.

The purpose of this investigation was to select biofilm-forming bacteria which can degrade or transform crude oil components leading to the solution of oil contamination causing by exploitation, transportation and use of oil and oil products. To gain this aim, several approaches such as enrichment to isolate and identify the bacteria that can utilize oil components and form biofilm and to assess oil degradation capacity of biofilm type in comparison with planktonic type of the strains. As results, the biofilm–forming Rhizobium sp. DG2 was isolated from oil contaminated sediment samples taken in petroleum storage in Ducgiang, Hanoi. The biofilm of this strain was capable of degrading 44.8; 76.0, 62.0, 73.0 and 75.0 % of diesel oil, anthracene, naphthalene, phenanthrene and pyrene, respectively, with the initial concentrations of 4.786 g/L for diesel oil and 200 ppm for the others. In contrast, the plantonik Rhizobium sp. DG2 in free form degraded only 35.4; 65.1; 54.5; 54.6 and 64.2 % of these components. The obtained results suggest the potential of using biofilm-forming bacteria in general and Rhizobium sp. in particular to treat oil pollution.

In the past 50 years, with the application of technical advances, the industrial chicken farming in the world has increased by more than 400%, an average increase of 3.30% per year while FCR reduced by 50%. In addition, the decoding the chicken genome, using candidate genes in line selection and breeding, building a pyramid breeding system... have made an important contribution to promoting the development of the chicken industry. At the same time, the application of the achievements of the Fourth Industrial Revolution such as Big Data, Internet of Things (connected things), Cloud computing (Cloud computing), Artificial Intelligence (A.I - Artificial Intelligence), Robotic Process Automation (RPA)... has helped people for early diagnose of the diseases, early detection of the sex of embryos while incubating eggs... providing active support for the livestock industry development and sustainability. However, besides the achievements, the chicken farming industry is also facing many great challenges such as globally increased price on input materials, implemention of animal welfare rights that require the chicken industry tremendous efforts to overcome as soon as possible.

Labour migration is a livelihood strategy that contributes to increasing income and improving the lives of migrant workers. Labour migration is increasingly common in developing countries. In Vietnam, in 2019 the country had 6.4 million migrant workers, accounting for 7.3% of the total population. Therefore, when the Covid-19 pandemic broke out, migrant workers were severely affected by losing jobs and income, falling into psychological stress and reduced quality of life. Although the Covid-19 pandemic was over the consequences of the Covid-19 pandemic still take a lot of time to overcome. Therefore, this article aimed to describe the impact of the Covid-19 pandemic on migrant workers in Vietnam by analysing domestic research results. The results of the article can be considered by concerned policymakers and governments to issue policies for migrant workers in the new context when the Covid-19 pandemic gone by. From there, lessons can be drawn for coping with other types of shocks that may occur in the future.