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Roles of Escherichia coliand Salmonellaspp. in Diarrhoea in Pre- and Post-Weaning Piglets: A Research in An Industrial Farm Model

Nguyen Anh Tuan, Nguyen Ba Tiep

Received: 17-04-2013 / Accepted: 19-06-2013
The contribution of Eschrichia coli (E.coli) and Salmonella spp. to diarrhoea of pre- and post-weaning piglets was investigated in Son Tra industrial farm in Bac Ninh province. The isolation rates for E.coli from fecal samples of pre- and post-weaning diarrheic piglets were 86.2 and 78%, respectively. Serotype O149 comprised the highest percentage (48%) followed by O101 (20%); O64 (12%) and O8 (8%) in isolates from pre-weaning piglets. Among isolates from post-weaning piglets, O141 comprised 43.7%, followed by O139 (28.1%), O149 and O138 (9.3% for each serotype). Genes encoding for STa, STb, LT, F4, and F18 were detected at 32; 44; 24; 44 and 32% in isolates from pre-weaning whereas, from fecal samples of post-weaning piglets, the detection rates was 65.5; 21.8; 59.4; 0 and 34.3%, respectively. The virulence was found higher for isolates from pre-weaning piglets. Salmonella spp. were detected only from fecal samples of post-weaning piglets with lower incidence in comparasion to previous reports and all of the isolates were S.typhimurium with very high virulence. High susceptibility of both E.coli and Salmonella isolates to Apramycin, Cephalothin, Amikacin, Certiofur was observed. Taken together, E.coli seemed to play a dominant role in diarrhoea of pre-weaning piglets in an industrial farm and that can be shared by Salmonella spp. in post-weaning counterparts.
Assessing Land Use and Land Cover Change: A Case of Tien Yen District, Quang Ninh Province from 2000 to 2010

Nguyen Thi Thu Hien, Pham Vong Thanh, Nguyen Khac Thoi

Received: 14-11-2013 / Accepted: 21-02-2013
The study was conducted to assess land useand land cover change in Tien Yen district in the 2000 -2010 period using SPOT images which were acquired in years 2000, 2005 and 2010. The object –oriented approach which was applied in this research includedtwomain steps: firstly, SPOT image was fragmented to vary objects by eCognition software, and, secondly,the segmentation images were classified by Maximum Likelihood approach using training dataset. The samples consisting of nineland usetypeswere collected by handheld GPSdevice. The overall accuracy of 3 image classifications in 2000, 2005, 2010 were 82.74%, 80,97% and 89.33%, respectively. Land useand land cover mapand land use/land cover change map were produced by ArcGIS (version 10.0) software to assess the land use change of the study area. Within 10 yearsperiod, the forest area and mangrove forest increased 3916.91ha and 1720.57ha, respectively. Meanwhile, the swidden and shrublanddecreased 4200.16ha. The increase of forest area in Tien Yen might be explained bybetter awarenessof local people about the benefits and the importance of forest as well as by thethe implementation of national and international projects which support Tien Yen in protecting and developing forest resource.
The Results of Purification of the Female Line and EstablishingProcedurefor Hybrid Seed Production of TheNew Two-Line Hybrid Rice Variety TH8-3

Vu Thi Bich Ngoc, Tran Thi Huyen, Pham Thi Ngoc Yen, Nguyen Van Muoi, Nguyen Thi Tram

Received: 26-11-2013 / Accepted: 03-02-2014
The new two-line hybrid rice variety TH8-3 (T7S-8/R3) has been recognizedastesting variety by Ministry of Agriculture and Rural Developmentin2010because it combines early maturity, high yield (6.0-8.0 tons/hectare), good lodging resistance and high grain quality. The yield of F1seed production is notyethigh becausethe parental linesare notcompletelypure and instable in terms of critical sterility temperature. Four successiveexperiments were conducted in growth chamber to screen/select female lines that havecritical sterility inducing temperature ≤ 240C,concurrently maintainheterosis of T7S-8/R3hybrid combination. Suitable planting dates and technical measures for F1seed production were also identified. These results can serve as basis to establish protocol for female line multiplication and procedure for hybrid seed production.
Purification and Expression of DNA Segment Encoding Highly-Antigenic Polypeptide from Capsid Protein P10 of Southern Rice Black-Streaked Dwarf Virus

Do Thi Hanh, Pham Thanh Tam, Pham Xuan Hoi

Received: 26-03-2015 / Accepted: 09-10-2015
Southern rice black-streaked dwarf virus-SRBSDV isa new virus species of the genus Fijivirusin the family Reovidae which caused serious rice losses in tens ofmillions of hectares throughout southern China and northernandcentral Vietnam during2009-2010period. To developsensitive and specific antibody for the diagnosis of SRBSDV based on ELISA method, a DNAfragment, namely P10.1, of the SRBSDV S10 segment, that encodes a highly-antigenic polipeptide, was cloned and expressed in E. coli.P10.1 consistingof525 nucleotides was cloned into vector pGEM®-T, then inserted into the expression region of pET28a and transfromed into E.colistrainRosetta to express recombinant polypeptide. Polypeptide fused with His-tag was expressedat 37°C,for16hwith 1.0 mM IPTGinducer. Using Ni-NTA chromatographic column recombinant polypeptide of about 35 kDa from cell extractswas purified. The purified polypeptide will be used as antigenfor inducing specific antibody against outer capsid protein of SRBSDV.
Calcineurin B-Like Protein Cbl4 and Cbl5 Participate in SignalTransductioninGerminating Rice (Oryza sativaL.) under Water Submergence

Ho Viet The, Pierdomenico Perata, Chiara Pucciariello

Received: 25-07-2014 / Accepted: 09-10-2015
OsCIPK15is a key regulator of starch degradation in rice due to submergence. This gene receives submergence signal via calcineurin B-like (OsCBL) proteins, which act as the Ca2+sensors, and whose role has yet to be established. In the present study, we compared the transcriptional regulation of CBLsin germinating rice embryos under water submergence. The trans-activation of OsCBLpromoters was tested by examining the effects of Ca2+. We used rice protoplasts to study the OsCBLs-OsCIPK15 protein interactions. We found that OsCBL4and OsCBL5were transcriptionally regulated under submergence.The Ca2+sensors OsCBL4 and OsCBL5 wereinvolved in this system and interactedon the plasma-membrane with OsCIPK15 in Ca2+dependent manner. Our results suggest that Ca2+signaling formed under submergence are inducedby OsCBL4and OsCBL5 which then interact with OsCIPK15 to activate genes involving instarch catabolism to provide energy for rice germination.
Hedonic Model and Software for Land Pricing and Selecting Key Feature of Land Price

Tran Duc Quynh, Bui Nguyen Hanh

Received: 22-07-2015 / Accepted: 03-09-2015
Land pricing and determining the key factors of the land price are useful for land use planning and for the banking. At present, landprice estimation is relied ontraditional methods. These methods largely depend onanalysis and intervention by pricing staff, thus, may not be free of subjective mistakes and non-transparency. In this study, we proposeda method for land pricing based on hedonic model. This model was introduced by Lancaster in 1966 and has many applications in economicsincluding land pricing. Usually, for each region, various particularmathematical models arechosen and tested. In this paper, we investigateda linear model and a secondorder model in combination withpenalty technique to select the key factorsaffecting land price. The optimal parameters were obtained by solving convex optimization problems. A demo software to calculate the optimal parameters and to evaluate the error was developped. Numerical results with data collected from Long Bien district showedthat the proposed method is potentially promising.
Taxpayer Satisfaction with Customer Service Quality of Nahang District’s Tax Bureau

Pham Bao Duong, Dam Thi Huong, Do Thi Hoa Nha

Received: 13-10-2014 / Accepted: 05-11-2014
Usingdatagatheredfrom surveying 132 taxpayers and applying exploratory factor analysis method and regression model, the presentarticle discusses the evaluation of tax-payers toward service quality of Na Hang District’sTax Bureau ofTuyen Quang Province. The study results showedthatservice quality,in general, has met the demand of tax-payerswith approximately 79,3%tax-payers satisfied with sevice quality. The research also identifiedseven factors affecting the satisfactory degrees of tax-payers. Those are: trustability, infrastructure, sympathy, equity and democracy, service capability, transparence/openess and accountability and responsiveness. The article also proposedmeasures to improve and enhance service quality of the tax bureau,thereby to enhance the satisfactionof tax-payers.
Extraction and Color Stability Evaluation of Crocin from Gardenia Jasminoides Ellis

Nguyen Thi Thanh Thuy, Nguyen Thi Hien

Received: 29-08-2016 / Accepted: 20-12-2016
Crocin belongs to the carotenoids group and is found a lot in Gardenia jasminoides Ellis. It is not only capable of creating color for food, but also has a lot of pharmaceuticalologicaleffects such as improving memory, anti-convulsants, anti-depressants, anti-oxidation, anti-tumor, etc.…The Oobjectives of this study wereisto detemine the crocin extraction methodology from Gardenia jasminoides Ellis and the color durability stability in different conditions. Carotenoid content was determined as described by Kotikova et al., 2011. Crocin content was determined by the Ultraviolet-visible spectroscopy (UV - VIS) at 440 nm wavelength. The results indicated that Gardenia jasminoideswas is apotential material to provide theobtainlarge highcrocin at concentrations,up to 16.04mg/g,for fresh material and 14.63mg/g for driedymaterial. The crocin extraction efficiency reached the peak with ethanol: water solvent (40:60, 50:50, v/v). The best results foroptimalsolvent : raw materials ratioand;fresh and dry materials extracting conditions corresponding were20ml/1g at 40°C in 45 minutes; 25ml/g at 70°C in 60 minutes, respectively. Crocin is stable at the temperatures below 100°C withinduring140 minutes. Besides, crocin is also stable in weak acidand,neutral and alkaline conditions.
Application of RT-PCRfor Detection of InfectiousbronchitisDisease in Laying Hens in Some Northern Provinces of Vietnam

Le Van Phan, Nguyen ThiLoan, Le Dinh Quyen, Duong Hong Quan, Le Huynh Thanh Phuong, Nguyen Ba Hien

Received: 23-03-2016 / Accepted: 20-09-2016
Infectious bronchitis (IB) is one of the severe infectious disease causing tremendous economic losses in the poultry industry. In order to have an effective strategy for disease prevention and control, a method for rapid and accurate dectection of infectious bronchitis virus (IBV) is urgently needed. In this study, the tissue samples oflung, trachea and kidney collected from IB-suspected laying hens in three hen farms in Hanoi (Ba Vi District), Thai Nguyen and Bac Ninh have been diagnosed by the RT-PCR method. The diagnostic results showed that 34/71 (47,88%) samples were positive with the IBV.The common clinical signs ofIBV-infected hens included fever, depression, loss ofappetite,dyspnea, coughing, sneezing, tracheal rales, nasal discharge, diarrhea, fluid retention in the abdomen, facial swelling and conjunctivitis. The pathological signs in IBV-infected hensincluded kidney swelling (90%), tracheal hemorrhagea (77.5%), pulmonary hemorrhage and congestion(63,7%), inflammation of airsacculitis (60%) and upper respiratory tract (57,5%). Egg production and quality in IBV-infected laying hensdecreased by 20,7to 43%.
Study on Alternative Methods to Green Malachite in Treatment of Ichthyophthirius multifiliis

Truong Dinh Hoai, Nguyen Van Tuyen, Nguyen Thi Huong Giang, Pham Thi Lam Hong

Received: 19-12-2015 / Accepted: 20-09-2016
The mixture of Green Malachite (MG) and formalin is the most effective chemical used to treat Ichthyophthirius multifiliis and other prasites infecting fish.However, MG was prohibited to usein aquaculture due to its potential risks to the environment, animal and human health. The prohibited use of MG has caused many difficulties to treat this parasite and other aquatic diseases. This study was conducted to examine a new, environmental friendly, safe and effectively method alternative to MG. Formalin 25 ppm (F25) was combined with a high oxidizing PHA (15% peracetic acid, 25% hydrogen peroxideand 25% acetic acid) at different concentrations of 1, 3, 5, 7, 10 ppm (PHA1, PHA3, PHA5, PHA7, PHA10) and the mixture was used to experimentally treat theronts (in vitro), and mature Ichthyophthirius multifiliis (trophonts) parasitized on Grass carp (in vivo), following with comparison to mixture of Green malachite and formalin (F25 + G0.25). The in vitrotest results show that the mixtureof F25 + PHA10 could kill 96.5% theronts within 48h. For in vivotest, treatments were conducted 72h post infection. After 10 days of experimental treatment, the control group (infected without treatment) had a high mortality rate (85.56%).In contrast, the F25 + G0.25 showed high efficiency in controlling this parasite with 94.43% fish survival. The mixtures F + PHA were effective to mitigate mortality rate compared to the control group, in which the mixture of F25 + PHA10 resulted in highest survival rate (92.23%), following with low prevalence and infection intensity, 5.13 and 1.81 parasites/sample at 40 x magnification, respectively. In addition, Ichthyophthirius multifiliis exhibited changes in morphology and moving behaviour. Results of following 10 days post treatment showed that fish treated with F25 + PHA10 recoveredeffectively, stopped mortality and probably created immunity against this parasite.
Identify the Effectiveness of Some Soybean Rust Resistant GenesonVietnam and Their Linkage Molecular Markers

Nguyen Van Khoi, Duong Xuan Tu, Nguyen Thanh Tuan, Nguyen Van Lam, Nguyen Huy Chung, Dinh Xuan Hoan, Le Thi Thanh, Nguyen Thi Thu, Phan Huu Ton

Received: 10-03-2016 / Accepted: 15-08-2016
Five genes Rpp1, Rpp2, Rpp3, Rpp4 & Rpp5 conferringresistancetoPhakopsora pachyrhiziSydow in soybean were identtified. Resistance evaluation of the soybean linescarryingresistant genes shows that genes Rpp2and Rpp4are highlyresistanttosoybean rust in Vietnam while Rpp5ishigh resistanttothe isolatesof rustpathogencollected from Southvietnam. The selection of molecular markers linkedto the above-mentionedresistance genes based on the analysisofcrossing populationsbetween resistant and susceptible cultivars shows that the markers Satt620, Satt288 and Sat_275 are closely linkedto Rpp2, Rpp4and Rpp5with the genetic distance of3.33cM, 2.50cM and4.16cM,respectively. Thesemarkers may beused to identify and select resistancegenes ingermplasm andresistant individuals in segregating populations.
Evaluating The Growth and Yield of Oyster Mushroom Strains (Pleurotusspp.) Cultured on Rice Straw

Nguyen Thi Bich Thuy, Nguyen Thi Lam Hai, Nguyen Thi Luyen, Tran Dong Anh, Nguyen Van Giang, Nguyen Thi Ngoc

Received: 09-06-2017 / Accepted: 12-12-2017
Oyster mushroom (Pleurotus spp.) is a delicious edible fungus with high nutritional and medicinal values. Itcontains all essential amino acids and several polysaccharides.Five strains of oyster mushroom werecultivated on rice straw sterilized at 121oC for 100 min and on rice straw piled for6-7 days at 60-70oC. The results showed that of5 oyster mushroom strains, PN1 showed the highest growth rate. In addition, sterilized straw was the most suitable material for the growth of PN1 with bio-efficiency at 73.8%. For further investigation, PN1 was cultured on a mixture of different materials including straw and some agricultural wastes such as cotton seed hull, sawdust, husk, and rice bran. It showed that the mix(in percent) with straw (84), cotton seed hull (10), rice bran (5) and CaCO3(1)was the best medium for the mycelial growth and fruitingbody yield and the bio-efficiency of PN1reached 77.4%.
Genetic Diversity of Hibiscus rosa-sinensisL. Accessions Collected in Hanoi and Hung Yen Province

Pham Thi Ngoc, Ngo Thi Hong Tuoi, Nguyen Thi Bich Hong, Doan Thu Thuy

Received: 05-12-2022 / Accepted: 18-04-2023
The study aims to evalute for morphological characteristics and genetic diversity of hibiscus. Twenty-four Hibiscus accessions collected in Hanoi and Hung Yen provinces (denoted as DB1 - DB24) were evaluated based on 12 morphological markers and 9 molecular markers (SSR and ISSR). The resutls showed that Hibiscus accessions exhibited significant variation in leaf morphology and flower colors, with 5 flower color groups, i.e white, pink, yellow, orange and red. The red color was predominant with 9 accessions. The genetic diversity analysis using 12 morphological characteristics grouped hibiscus accessions into 5 groups at similarity coefficient of 0.55 similarity, of which DB4 and DB20 were in each separate group. Nine molecular markers SSR and ISSR produced 33 allenswith average of 3.67 allens/markers and all were polymorphic. PIC values ranged from 0.05 to 0.47 in which HB15 marker had the highest PIC value. With the similarity coefficient at 0.64, 24 accessions were divided into 3 distinct clusters.
Consumer Awareness of Low-Quality Chemical Fertilizers in Bao Thang District, Lao CaiProvince

Le Thi Thanh Loan, Nguyen Thanh Phong, Duong Thi Tan

Received: 15-04-2024 / Accepted: 24-06-2024
The research was conducted in Bao Thang district, Lao Cai province to assess consumer awareness of low-quality chemical fertilizers. The information was collected through group discussion, in-depth interviews with stakeholders in fertilizer management and business, as well as a survey with a questionnaire administered to 90 consumers across 3 communes with large agricultural areas in the district. The results showed that consumers faced the most difficulty in recognizing the visual characteristics of low-quality fertilizer packaging. Regarding the harmful effects of low-quality fertilizers, most people could relatively recognize them, but the awareness of how to handle low-quality fertilizers was limited. Some challenges to consumer awareness include the sophistication in the strategy of producing low quality fertilizers, the sources of information available to consumers, and consumer characteristics. The study proposes several solutions to enhance consumer awareness of low-quality fertilizers, focusing on solutions for consumers, solutions for the district authority, and solutions for reputable fertilizer suppliers.
Study on using Cellulase in the Processing of Beverage from Medical Mushrooms

Nguyen Thi Bich Hang, Nguyen Doan Nhat Quynh, Ho Thi Trang, Doan Chi Cuong, Bui Duc Thang, Tran Dinh Chi

Received: 18-08-2023 / Accepted: 12-04-2024
Cellulase was applied to improve the extraction efficiency from medicinal mushroom extracts of Ganoderma lucidumand Trametes versicolor. In addition, the study proposed the process of producing beverages from those medicinal mushrooms and chrysanthemum (Chrysanthemum indicum)flowers. The findings show that, for extracting from Yunzhi’s extract, using 3% cellulasefor 15 minutes attemperature of 70C gained the highest extraction efficiency. Meanwhile, the extraction efficiency from Lingzhi’s extract was highest with 4% cellulasein 25 minutes attemperature of 70C. Mushroom beverage with a mixture of 25% Lingzhi, 50% Yunzhi, 20% Chrysanthemum flowers, and 5% sweet grass (Stevia rebaudiana) had the highest sensory evaluation according to the TCVN3215-79. The processed product meets quality standards on food hygiene and safety according to QCVN 8-2/2011-BYT for permissible limits of heavy metals and Decision 46/2007/QD-BYT for biological and chemical contamination in food.
Analyzing the Role of Intrinsic Motivation in Continuing Information Sharing Behavior ViaSocial Media

Le Xuan Cu

Received: 07-08-2023 / Accepted: 07-03-2024
The purpose of the present studywasto enlighten continuing information sharing behavior via social media among users in Vietnam. The studyapplied the motivation theory to develop a research model of continuing information sharing intention via social media. Data were collected from 494 respondents who have used social media platforms and shared information via those platforms. Structural equation modeling was utilized to assess the proposed model. Results indicate that intrinsic motivation played an essential role in fostering continuance intention to share information via social media. In addition, exhibition, targeting, informative attractiveness, emotion, and source credibility exterted significantly positive influences on intrinsic motivation toward information sharing via social media. Lastly, academic and managerial implications were discussed to contribute to the current literature on social media-based consumer behavior and promote information sharing on the Internet.
Analyzing the Role of Intrinsic Motivation in Continuing Information Sharing Behavior ViaSocial Media

Le Xuan Cu

Received: 07-08-2023 / Accepted: 07-03-2024
The purpose of the present studywasto enlighten continuing information sharing behavior via social media among users in Vietnam. The studyapplied the motivation theory to develop a research model of continuing information sharing intention via social media. Data were collected from 494 respondents who have used social media platforms and shared information via those platforms. Structural equation modeling was utilized to assess the proposed model. Results indicate that intrinsic motivation played an essential role in fostering continuance intention to share information via social media. In addition, exhibition, targeting, informative attractiveness, emotion, and source credibility exterted significantly positive influences on intrinsic motivation toward information sharing via social media. Lastly, academic and managerial implications were discussed to contribute to the current literature on social media-based consumer behavior and promote information sharing on the Internet.
Study on Preparation of Chitosan Nanocapsules Transduced with Trans- cinnamaldehyde for Communication Inhibition in E. coli Top10

Dong Huy Gioi, Nguyen Thanh Hao, Nguyen Thi Bich Luu

Received: 27-02-2023 / Accepted: 05-01-2024
This study was conducted with the aim of preparing chitosan nanocapsules transduced with trans-cinnamaldehyde for communication inhibition in bacteria. We used emulsification method to synthesize nanocapsule and nanoemulsion complexes. The nanocapsule and nanoemulsion complexes were transduced with trans-cinnamaldehyde using an oil nucleus and chitosan as cover. The nanocomplex had a uniform particle structure, low dispersion, and the size ranges from 120 to 150nm. Both nanocapsule and nanoemulsion were stable in bacterial culture after 24h of incubation. The trans-cinnamaldehyde transduction efficiency for the nanocapsule and nanoemulsion complexes was 86 and 73%, respectively. Both complexes released the drug through two stages, slowly in the first 6 hours and followed by continuous drug release after 12 hours, reaching 35 and 45%, respectively, for the nanocapsule and nanoemulsion. Bioassays with the E. coli Top 10 biosensor showed that nanocapsule was superior to nanoemulsions in inhibiting bacterial communication, also known as quorum sensing. In the best formulation, nanocapsule inhibited the communication process in this bacterium up to 65%.
Effects of Culture Conditions on Mycelial Growth and Fruiting Bodies of Trametes versicolorMushroom Tra-6 Strain

Tran Thu Ha, Nguyen Van Giang, Nguyen Duy Trinh, Nguyen Thi Phuong

Received: 03-10-2023 / Accepted: 25-12-2023
Turkey tail mushroom (Trametes versicolor) is a medicinal mushroom used as a health-promoting pharmaceutical, extending life, and adjuvant therapy for cancer patients. The mycelia and fruiting bodies of the Turkey tail mushroom contain various biologically active compounds such as polysaccharides, glucans, phenolics, flavonols, coumarins, isoflavonoids, triterpenoids, and sterols. This study was carried out to choose the optimal culture conditions, including culture pH, temperature, medium, and substrate composition, for the growth of the mycelia and fruiting bodies of the T. versicolor mushroom Tra-6 strain, collected in Lao Cai, Vietnam. The experimental factors were examined individually in a randomized complete block design. Research results show that the mycelia of the Turkey tail mushroom Tra-6 strain quickly grew on MCM and YEA media at pH 8 and 25 ± 1C. Sucrose, yeast extract, MgSO4.7H2O, KCl, and KH2PO4 were the optimal carbon, nitrogen, and mineral salt sources for this strain, respectively. Tra-6 strain had the ability to form fruiting bodies when growing on substrate from agricultural by-products. The highest yield of 44.4kg dry mushroom per ton of dry substrate was obtained on a substrate consisting of 55% sawdust, 24% crushed corncobs, 20% rice bran, and 1% CaCO3 powder.
Evaluation of Growth and Development of Tisue Culture-derived Plants ofFour GerberaDaisy (Gerbera jamesonii) Cultivars

Pham Thi Huyen Trang, Phung Thi Thu Ha

Received: 21-03-2023 / Accepted: 05-10-2023
Gerbera, which is diverse in colors and types of flowers, is a high valuecut flower in both the domestic and international markets. This study aimed to evaluate the growth and development of tisue culture derived plants of four cultivars of Gerbera (Red, Pink, Orange, and Yellow). The experiment was designedin a randomized completeblock design. The study results showed that, in the nursery stage, tissue culture plantlets had 83.33-100% survival rate, with 6.9-8.3 leaves/plant, and plant height in the range of 6.44 to 7.28cm after 1.5 months of transplanting. In the production stage, the survival rate of all four Gebera cultivars reached 100%, with 9.4-11.4 leaves/plant, and 26.95-34.05cm in height after 3.5 months of transplanting. The flower stalk diameter of four Gebera cultivars ranged from 5.55 to 6.13mm, and the flower stalk height reached from 39.67 to 46.14cm. The maximum head diameter of four cultivars reached 8.65-9.41cm. The head longevity from bud to fade was29.20-31.70 days. The head inflorescence longevity from fullbloom to fade was8.80-12.40 days. All four studied Gerbera cultivars grewand developed well and wereless affected by pests and diseases, suitable for planting in Gia Lam, Hanoi.
Constructing Local Orbit for Self-Operating Robot in Agricultural Greenhouse Based on ROS

Pham Thi Lan Huong, Nguyen Thi Duyen

Received: 06-01-2023 / Accepted: 05-10-2023
This paper proposed a local path planner coping with the collision-free navigation problem which considers both static and dynamic obstacles based on Timed Elastic Bands (TEB)aggregated with Simultaneously Localization and Mapping (SLAM) for self-operating/mobile robots working in thegreenhouse environment. Moreover, the proposed system is a four-wheel Omni robot constructed using Robot Operating System (ROS) platform and implemented in a high-performance embedded computer Jetson-TX2 connected with a 3D camera and lidar to collect environmental data. The simulation results based on Gazebo and Rviz software show the effectiveness of using the ROS operating system, with the TEB algorithm in controlling and monitoring autonomous moving robots, avoiding obstacles in the greenhouse This is a research direction with great potential in high-tech agricultural applications.
Study on the Co-Infections of Several Pathogensin Chickens Having Respiratory Symptoms

Nguyen Van Giap, Nguyen Thanh Trung, To Nhu Tuong, Truong Ha Thai, Chu Thi Thanh Huong, Dang Huu Anh, Mai Thi Ngan, Tran Thi Huong Giang, Le Van Truong, Vu Thi Ngoc, Cao Thi Bich Phuong, Huynh Thi My Le

Received: 17-04-2023 / Accepted: 29-08-2023
Respiratory disease complex has emerged as a major challenge for the poultry industry. Pathogens and co-infections in respiratory disease complex such asviruses (AIV, IBV, ILTV, NDV, aMPV) and bacteria/mycoplasma (APG, ORT, APEC, MG) were anattractive research topics worldwide. In Vietnam, the etiology of respiratory diseases has only been noticed in the last few years. Due to its novelty, by molecular biology technique, this study was conducted to detect several pathogens in chickens suffering from respiratory diseases in northern Vietnam. There were 127/157 (80.9%) of the samples positive for at least 1 out of 9 viruses, bacteria/mycoplasma (AIV, IBV, ILTV, NDV, aMPV, APG, ORT, APEC, MG). Of those 127 positive samples, the highest frequency (100/127) was the co-infections between viruses and bacteria. Among 51 co-infection patterns, 41/51 patterns were the co-infection between 2-6 agents.
Mycelial Growth and Fruiting Body Development of theTu Cau Oyster Mushroom (Pleurotus spp.) Cultivated on Different Culture Substrates

Nguyen Thi Huyen Trang, Truong Hong Lam, Nguyen Thi Mo, Ngo Xuan Nghien, Nguyen Thi Luyen, Nguyen Thi Bich Thuy

Received: 10-03-2023 / Accepted: 29-06-2023
Oyster mushrooms (Pleurotusspp.) are highly nutritious and delicious edible mushrooms with a high economic value but the yield depends on several factors. This study aimed to identify the optimal carbon and nitrogen sources, temperature, and cultivation substrate for promoting mycelialgrowthandfruitingbodydevelopmentof theTuCauoystermushroom strain P35. In this study, mycelial of the Tu Cau oyster mushroom strain P35 were incubated in 5 different temperature levels (15°C ± 1, 20°C ± 1, 25°C ± 1, 30°C ± 1, 35°C ± 1); using medium supplemented 5 different carbon sources (glucose, fructose, maltose, saccharose, lactose), 5 different nitrogen sources (peptone, yeast extract, ammonium sulfate, casein, ammonium nitrate) and 5 spawning substrates to evaluate filamentous growth. At the same time, mycelial of this strain were cultured in 4 kind of materials (Cotton waste, corn cob, straw, sawdust) to value the fruiting body development.The results showed that the ideal temperature for the favorable mycelial growth of theTuCauoystermushroom strain P35 was 30°C ± 1. Maltose and (NH4)2SO4were considered the most suitable carbon and nitrogen source, respectively. 99% boiled rice spplemented with 1% calcium carbonate (CaCO3)] was the optimal spawning material for mycelial growth. The highest yield performance (48.24%) of theTuCauoystermushroomstrain P35 was obtained when cultivated on a substrate mixture of 94% cotton, 5% wheat bran, and 1% CaCO3.
Morphorlogical Characteristics, Growth Performance and Carcass Yield of Van Linh Chicken

Duong Thu Huong, Nguyen Thi Chau Giang, Nguyen Van Thong, Nguyen Khanh Toan, Dang Thuy Nhung, Nguyen Hoang Thinh

Received: 07-12-2022 / Accepted: 22-05-2023
This study was carried out to determine morphological characteristics, growth performance, carcass yield and meat quality of Van Linh chicken raised at the Faculty of Animal Science, Vietnam National University of Agriculture. A total of 120 Van Linh 1-old-day chickens were randomly assigned into 3 groups and they were fed and taken care following the standards for colored feather chicken of Thuy Phuong poultry research center, National Institute of Animal Science.The results showed that, , the feathers of day old chicks were light yellow (71.5%), light brown (20%) and yellow with black spots (8.5%); at 18 weeks of age, hens’body coat colour was characterized by light yellow (47,5%), light brown (33.,4%) and dark brown (19.1%), 62% of hens had black spots on the neck; the cocks were characterized by burgundy (75.8%) and dark brown (24.2%). All chickens had single comb with bright red color; The legs, skin, and beak were saffron yellow. The survival rate until 18 weeks of age was 95.83%. At 18 weeks of age, the body weight of male chicken was 2,244.34g and female chicken is 2,067.38g. FCR was 3.98. The percentage of carcass, thigh meat and breast meat of male chicken were 72.69, 21.48, and 14.94%, respectively and anf the figures for female chicken were 71.68, 16.77 and 16.14%, respectively. Drip loss of preservation and cooking for 24 hours, pH value, color, and tenderness were in good ranges and well suited.
Isolation and Antimicrobial Susceptibility of Streptococcus agalactiaeCausing Cloudy-eye Disease in Thai Frog (Rana tigerina) Cultured in Northern Vietnam Provinces

Dang Thi Hoa, Vu Duc Manh, To Thi Ngoc Anh, Tran Thi Trinh, Doan Thi Nhinh, Kim Van Van, Truong Dinh Hoai

Received: 16-12-2022 / Accepted: 27-03-2023
The study was conducted to determine the disease characteristics., isolation, identification, and evaluation of antibiotic resistance ofStreptococcus agalactiaecausing blindness in Thai frog(Rana tigerina)raised in Northern provinces ofVietnam. The infected frogs(n=83) were sampled from 26 frog-raising farms in Hanoi, Ha Nam, and Thai Binh provinces. Infected frogsexhibited opaque eyes, blindnessin one or both eyes (78.3%), skin darkening (53.0%), and swelling and hemorrhage liver (69.9%). The bacteria isolated from the eye, brain, kidney and liver of infected frogs were round, convex, cream-coloured, pinpoint (1mm), Gram (+), and of coccus type.Twenty sixstrains isolated from frogs were identified as S. agalactiaebased on morphological, biochemical, and PCR analysis. The LD50of three representative strains were between 1.2×104 to3.5 ×104CFU/frog. The isolated bacteria were highlyresistant to oxytetracycline and sulfamethoxazole/trimethoprim (61.5%), buthighly sensitive to amoxicillin, florfenicol, and erythromycin (65.4-80.8%).These results providesuseful information for effective prevention of the disease caused by S. agalactiaein cultured frogs.

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