Vol. 19 No. 11 (2021)

The objective of this study was to evaluate the effects of incubation time, seeding depth and sowing density on yield of inbred rice cultivar ĐH12 for the use of air-assisted strip direct seeding cultivation in the Red River Delta. The experiments were designed in randomized complete block design (RCBD) withfive germination times, five seeding depths l and six sowing densities in the 2019 summer season at Gialam district, Hanoi. The results showed that f 12 hours incubation, 1.0cm sowing depth 1.0cm, and sowing density with row ×row = 20cm; hill x hill from 11.0 to 12.5cm (sowing density 40-45 hills/m2) were most suitable for ĐH12 cultivar with the highest yield

This study was conducted to evaluate carcass characteristics, meat quality, and chemical composition of meat of Crossbred F1(Ho × Luong Phuong - HLP) chickens raised in the animal farm of Vietnam National University of Agriculture from June 2019 to March 2021. Data on carcass characteristics, meat quality and chemical composition were collected from 18 chickens (9 males and 9 females). The results showed that, the HLP cocks had slaughtering weight (2.74kg), carcass percentage (69.75%) higher (P <0.05) than those of hens (2.19kg and 65.91%). The thigh meat percentage of cocks (22.20%) and hens (23.13%) were higher than pectoral meat percentage (15.28 and 16.06%). The gender did not affect the traits of pectoral and thigh meat quality of HLP chickens (P >0.05), except for pH value at 15 minutes’ post mortem. The dry matter, crude lipid and ash were not significantly different for gender (P >0.05), except crude protein of thigh meat (P <0.05). The slaughter weight of HLP chickens at 15 weeks of age was high, but carcass percentage was low. The meat quality and chemical composition of pectoral and thigh meatof males and females HLP were good and acceptable for chicken meat quality.

With the aim of studying some epidemiological characteristics of ASF in Vietnam, the study was conducted for the first time in pigs raised in Quynh Phu district, Thai Binh province.In Quynh Phu district, the epidemic started on 26thFeb, 2019 and then spread to the whole district. The average sickness rate of pigs in the district was 32%. In the farms under study, the disease occurred at high rate in small farms (71.43% on average) with the highest rate of 91.95%, while in 33.33% of mediumand large sized farms, the pigs were infected with the lower rate (41.23%). The rate of ASF-infected pigs was in the following order: boar (57.14%), porker (41.95%), sow (40.63%) and piglet (39 , 01%). The symptoms and lesions of ASFinfection were relatively similar among pigs. PCR analysis showed that the virus pre-existed in the farms. Virus sequencing showed that the gene fragment was similar to that of the pathogenic strains in other regions in Vietnam and around the world. In summary, ASF is a dangerous, fast-moving, and acute epidemic with complex epidemiological characteristics in Vietnam. It is essential to conduct research on the disease situation in other localities as well as other provinces in the country to compare the results between different localities to get the best overview of disease.

The study was conducted to evaluate the growth performance and feed conversion ratio (FCR) of [BBB ×F1(BBB × Lai Sind)] crossbred calves raised in farm condition in Ba Vi district, Hanoi city, Vietnam. A total of 20 animals iconsisting of 10 male and 10 female calves from 6 to 12 months of age were used in this study. Calves were kept in individualy and fed a mixture of forage and concentrate. The results showed that [BBB ×F1(BBB ×Lai Sind)] crossbred calves grew well with good feed efficiency in farm conditions. Calves weighed 198.9 kg and 356.05 kg at 6 and 12 months, respectively. Average daily gain (ADG) in the period of 6-12 months of age was 873.05 g/head/day. Feed conversion ratio in the period of 6-12 months was 8.55 kg DM/kg. Gender affected body weight, ADG, and FCR (P<0.05). The male calves had higher body weight, ADG and lower FCR as compared to female calves.

This study was conducted to evaluate the effect of the supplement of organic rare earth elememts (REE-citrate) in broiler diets on growth performance, carcass characteristics and meat quality. The experiment was done according to a completely randomized design on 1,000 chicken from 1 day of age and divided equally males and females into 5 treatments (200 chicken/treatment) with 4 replicates as follows: treatment 1 (Control): basal diet (KPCS); treatment 2: KPCS + 50mg REE-citrate/kg feed; treatment 3: KPCS + 100mg REE-citrate/kg feed; treatment 4: KPCS + 150mg REE-citrate/kg feed; treatment 5: KPCS + 200 mg REE-citrate/kg feed. Results showed that supplementation of 150 and 200mg REE-citrate/kg feed improved daily weight gain and feed conversion ratio of broilers from 1 day of age to slaughter by 4.77-12.47% and 4.48-12.60%, respectively. Supplementation of REE-citrate did not affect the carcass characteristics and broiler meat quality, however, the level of 200mg REE-citrate/kg feed decelerated pH value in breast meat after 24 hours.

The experiment aimed to to evaluate the effect of Lactobacilus rhamnosus and Saccharomyces cerevisiaecell walls (probiotic cell wall mixture) supplement on growth performance, meat quality and feed efficiency of growing - fattening pigs. Total 84 weaning pigs (PiDu ×LY) (6.6 ± 1.45 kg) were used in an experiment with four treatments (21 animals/treatment, devided in 3 pens with 7 animals each). The experimental animals were fed the basal diet and supplemented with 0%; 0.01%, 0.03%, 0.06% probiotic cell wall mixture, conresponding to negative control group (ĐC) and experimental groups (IV0.01, IV0.03, IV0.06), respectively. Results showed that, the probiotic cell wall mixture did not affect the intake but improved growth rate (ADG) and feed efficiency (FCR), i.e increased ADG by 3.1% to 6.9% and reduced FCR by 2.65% to 7.75%. Supplement of probiotic cell wall mixture reduced feed cost per kg ADG by 2% to 5% but did not affect meat quality. As a result, probiotic cell wall miture should be provided at 0.03% in pig diet.

The objectives of this work were to select carotenoid-producing red yeast strains and assess the impact of various parameters such as temperature, pH, C and N sources on dry biomass and their carotenoid production. A total of 8 Rhodotorulastrains, viz. SR1, SR2, SR3, SR4, SR5, SR6, SR7, SR8 were inoculated on Hansen broth at 30C/72h. The highest carotenoid producing yeast strains SR6 and SR7 (0.76 and 0.81 mg/gDM) were selected to further study the effect of inoculation percentages, temperature, pH, as well as C and N sources on growth and carotenoid production. The results showed that the two selected red yeast strains grew fast and produced the highest carotenoid when cultrured on liquid Hansen medium with 2% innoculation rate at 30C and pH 5.5. The optimum sources of N and Cfor red yeast culture medium were petptone and glucose, respectively. Corn meal and rice flour were chosen as the best substrates for solid fermentation.

The study aimed to point out the advantages, disadvantages and causes and, thereby, propose solutions to overcome the disadvantages when implementing financial revenues from land (FRL) in Vinh city. Secondary data were collected at Vinh City People's Committee. A total of 267 households and 99 civil servants related to FRL were surveyed. In the 2016-2020 period, total land revenue was VND3,125,967 million, accounting for 24.64% of total budget revenue, wherein the land use fee was VND2,596,237 million (83.05%) and the land rent was VND397 million (0.01%). The constraints were lack of operating human resources, lack of updated land database and linkage between all levels and sectors, limited information technology application, frequent occurrence of financial obligation violations, and high rates of tax and fee in land use right transfer. The solutions recommended include ensuring sufficient human resources, fully updated land database, ensuring communication among all levels and sectors, enhancing the application of information technology, promoting propaganda and dissemination of the law, violation sanction, and improving some financial revenues.

The study aimed to select Bacillus subtilisstrains which are capable of producing β-glucosidase to hydrolyse ginsenosidefrom the root of Panax pseudoginsenginto the bioactive compound Rg3 and CK. Twenty four strains were primary screened for the β-glucosidase n using 0.1% azo-CMC and 0.3% azo-Avicel. The classification of strains based on the morphology and phylogeny was analysed by the sequence of 16S. β-glucosidase activity obtained from strains was determined by DNS method using PNP-β-D-glucopyranoside substrate. The hydrolysis of ginsenoside to Rg3 with enzyme β-glucosidase was identified using thin layer chromatography (TLC). Rg3 and CK content were determined using high performance liquid chromatography HPLC). Results showed that Bacillus subtilisstrain NL812 produced β-glucosidase with the highest activity. The β-glucosidase released from Bacillus subtilisstrain NL812 hydrolyzed ginsenoside from Panax pseudoginsenginto Rg3 and CK after 30 min. with Rg3 content increased by 50.3% andCK content increased by 47.7%.

Program evaluation and review technique and critical path method are powerful computing tools in project scheduling and project crashing. However, in Vietnam, modeling and computing aspects of program evaluation and review technique and critical path method have not yet been considered sufficiently and systematically in university education and applied research as well as in project management of agricultural production and business and many other fields. Besides reviewing fundamental knowledge of program evaluation and review technique and critical path method, this paper proposed the application of linear programming in project scheduling for determining project’s critical activities and critical path as well as for crashing project’s activities in order to shorten project completion time with a minimum total crashing cost. As a result, utilizing the modeling method and the scientific computing method, new linear-programming-based algorithm frames were constructed for efficiently supporting project analysis and management with program evaluation and review technique and critical path method.

The objective of this study was to find the optimal value of the factors that directly affect the bacterial population multiplication process as a premise to create products that apply in reality with emphasis on Pseudomonas stutzeriKL15 strain. Pseudomonas stutzeriKL15 grew and developed well when the bacterial culture rate was 2.5%, after a culture time of 36 hours at 30C. After that, appropriate nitrogen and carbon sources were selected as the basis for screening factors affecting the biomass collection of Pseudomonas stutzeriKL15by experimental design Plackett - Burman. The fermentation medium composition was optimized by the Response surface methodology (RSM) with Box - Behnken matrix, in which three factors, molasses, yeast extract and MgSO4were the the most influential factors (P <0.05). Results showed that the suitable media composition to receive Pseudomonas stutzeriKL15biomass included molasses 4.76 g/l, yeast extract 18.99 g/l and MgSO40.99 g/l. The actual concentration of Pseudomonas stutzeriKL15obtained was 2.37 ×1011CFU/ml in comparison withthe predicted maximum concentration of Pseudomonas stutzeriKL15of 2.45 × 1011CFU/ml (11,591 Log10.CFU/ml).

Snow mushroom (Tremella fuciformis) is a high-value edible mushroom. Polysaccharide compounds from T. fuciformisexhibited various biological activities such as improving the immune system and antioxidant, anti-tumor, and anti-inflammatory activity. This study was carried out to investigate the effects of different carbon sources (glucose, fructose, lactose, maltose, sucrose) and nitrogen sources (yeast extract, peptone, NH4NO3, (NH4)2SO4, (NH4)2HPO4and NH4Cl) and mineral salts (MgSO4.7H2O, KH2PO4and ZnSO4) on the mycelium growth of the snow mushroom strain Tre-1. Snow mushroom Tre-1 was grown on PA medium supplemented with 20g/l of different carbon sources, including glucose, lactose, maltose, fructose, sucrose, to evaluate the effect of carbon source on the growth and development of mycelium. Similarly, to investigate the effect of nitrogen source on snow mushroom mycelia, experiments were carried out on PA medium supplemented with 20 g/l glucose and 1.0 g/l different nitrogen sources, including yeast extract, peptone, NH4NO3, (NH4)2SO4, (NH4)2HPO4and NH4Cl. The effect of glucose/peptone ratio and a mineral source on the growth of mycelia of Tre-1 mushroom was evaluated based on the experimental results of growing Tre-1 mycelia on PA medium containing 1 g/l of peptone added 15, 20, 25, 30, 35 and 40 g/l glucose respectively, and 0.25 g/l mineral salts MgSO4.7H2O, KH2PO4and ZnSO4. Results indicated that the optimal carbon and nitrogen sources for the mycelial growth of T. fuciformisstrain Tre-1 were glucose and peptone, respectively. The optimum glucose/peptone ratio was in the range of 20:1 to 25:1. MgSO4.7H2O was identified as the most effective source.

With the aim of creating disease-free, homogeneous seedlings for growers in large quantity in a short time, this study evaluates the effect of the HgCl2(mercury chloride), BA (N6-benzyladenine), Pic (picloram), TDZ (thidiazuron), kinetin, IBA (indole-3-butanoic acid), and α-NAA (α-naphthaleneacetic acid) at different concentrations on in vitro propagation of strawberry cv. Sunraku. Research results showed that using 0.1% HgCl2for five minutes gave 100% disease-free samples on the MS medium. MS medium supplemented with 0.75 mg/l BA and 0.3 mg/l IBA gave the highest shoot number (23.1 shoots per explant) and good quality. Half MS medium combined with 0.3 mg/l α-NAA was the best medium for rooting (18.6 roots per shoot). The research also showed that in vitroseedlings have the highest surviral rate (100%) and best development when they were grown on a mixed substrate (1 soil : 2 burn rice husks : 1 coconut fiber). The number of chromosomes (2n = 8x = 56) of regenerated plants was similar to that of the mother plant.

This study evaluated the general impacts of the value chain upgrading process and the positive aspects of the upgraded value chain in comparison with the value chain of external cooperatives/cooperative groups. The chain upgrading process was conducted in three cooperatives/cooperative groups categorized into three types of value chains, including open chain, linked chain, and closed chain. The product lines selected for the chain upgrading based on the classification of the Vietnam Food Association (VFA) consisted of two groups. The first one involved specialty rice that is fragrant, soft, and of high quality such as ST24, Dai Thom 8, and Jasmine 85. The second group consisted of long-grain white rice with light fragrance and high quality. The expansion models (MHMR) followed VietGAP, SRP, and organic standards in rice cultivation to meet the market needs. In the course of organizing global value chains, the connection between the market represented by export enterprises and raw material areas is essential. It becomes a primary condition to upgrade the value chain, in which risk and benefits sharing must be discussed and maintained over the long term. This contributes to create standardized products according to the current market needs and to affirm the Vietnamese rice brand.

The purpose of this study is to assess the current situation and propose solutions for developing high-tech agriculture in Ho Chi Minh city. The data compiled from reports of the Department of Statistics, Department of Agriculture and Rural Development, People’s Committee of Ho Chi Minh city and survey results were analyzed using descriptive statistics and synthetic, comparative and inductive methods. The research results showed that high-tech agricultural production of Ho Chi Minh city has achieved high efficiency in terms of economic, social and environmental aspects. The production value accounted for 59.3% of the city’s total agricultural production value and the average growth rate reached 123.12%/year in the 2010-2020 period. High-tech agricultural production (vegetables, orchids, pigs, dairy cows, shrimp, ornamental fish) of households achieved high economic efficiency, output increment, income improvement, reduction of damage rate, produce traceability, consumption market stability and close linkage with traders. The solutions for planning, developing production forms, promoting technical application, attracting investment, developing joint production, preprocessing/processing and product consumption were recommended for the development of hi-tech agriculture in Ho Chi Minh city.