The Journal of Agriculture and Development

Optimization of ultrasound-assisted enzymatic extraction of betalains from red beetroot (Beta vulgaris L.)

Tien Dat Huynh — 2023-12-11

Betalains in red beetroot (Beta vulgaris L.) offer health benefits and are commonly used as a food colorant. This study aimed to investigate betalains extraction using ultrasound-assisted enzymatic extraction (UAEE). The most significant factors involved in UAEE such as enzyme concentration, extraction temperature, and extraction time were studied and optimized using the response surface method (RSM) to achieve the highest betalains yield. The results showed that the optimal extraction conditions were as follows: enzyme concentration (32.1 U/mL), extraction temperature (40^oC), and extraction time (117 min) gave the highest yield of betalains at the level of 550.51 ± 25.76 mg/L. The findings are promising for the industrial scale of extraction betalains for food applications.

Friedel-Crafts sulfonylation catalyzed by chloroaluminate ionic liquid immobilized on magnetic nanoparticles: Optimization by response surface methodology

Thi Ngoc Lan Nguyen — 2023-12-11

This study focused on optimizing the Friedel-Crafts sulfonylation reaction between 1,3-dimethoxybenzene and p-toluenesulfonic anhydride using chloroaluminate ionic liquid immobilized on magnetic nanoparticles as the catalyst. Various reaction conditions including the ratio between reagents (0.9:1.0 - 1.1:1.0), the catalyst amount (0.1 - 0.3 g), reaction temperature (100 - 120^oC), and time (1 - 3 h) were optimized using response surface methodology based on a central composite design model. The results showed that the optimal reaction conditions were achieved at 115°C for 2.3 h, using 0.24 g of catalyst with a reagent ratio of 1.0:1.0, resulting in the highest sulfones yield of 82%.

Sex reversal using 17 α-methyltestosterone immersion and its effect on sex reversal and growth performance of Nile tilapia (Oreochromis niloticus L., 1758)

Hai Dang Nguyen — 2023-12-11

The study aimed to evaluate the optimal dose of 17 α-methyltestosterone (MT) and stocking density using immersion method for maximum survival, masculinization rates and growth performance of Nile tilapia (Oreochromis niloticus). The experimental design employed complete randomization including three concentrations of 17 α-methyltestosterone (1.5, 2.0, and 2.5 mg/L) and three stocking densities of 500, 750, and 1000 fish/L and a control group, arranged in three replicates. The control groups consisted of 3 stocking densities of 500, 750, & 1000 fish/L and fish were kept in glass aquaria containing MT-free water. Fish were exposed to MT solution for 2 h, and the fish were then transferred to nursery in hapas in earthen ponds at a density of 1,000 fish/m²for 60 days. After the hormone treatment and 60 days of rearing, the highest survival rate was found in the control group. The male ratios in the MT treatments ranged from 78.9 to 91.1% and were statistically higher than that in the control (55.1%) (P < 0.05). The most effective doses and stocking density in sex-reversal of the tilapia fry using immersion method were 2.0 mg 17 α-MT/L and 750 fish/L, respectively. The mean weight and length of fish in the MT treatments were greater than those in the control treatment, although the difference was not statistically significant (P > 0.05). The results also showed that the average weight of experimental fish was directly proportional to the hormone concentration but inversely proportional to the stocking density. Based on the study findings, the recommended dose for producing maximum mono-sex male tilapia is 2.0 mg 17 α-MT /L, and the most suitable stocking density is 750 fish/L.

Prevalence of dermatophytosis and Malassezia infection in dogs and cats in Thonglor Bangkok Pet Hospital in Ho Chi Minh City, Vietnam

Truong Trung Nguyen — 2023-12-11

Malassezia yeasts are occasional human and animal skin organisms that commensally act as pathogens, while dermatophytes are common fungi in many clinics and hospitals. The aim of this study was to evaluate the prevalence of dermatophytosis and Malassezia infections in dogs and cats, and the effect of treatments. The study was carried out from December 2022 to May 2023 in Thonglor Bangkok Pet Hospital, Ho Chi Minh City, Vietnam. Total 208 cases visited the hospital, in which 32 cases of otitis and 53 dermatitis were recorded. Sterile cotton swabs were used to collect the aural samples from 32 cases, then observed under the microscope to detect the presence and population of Malassezia yeasts. In 53 dermatitis cases, adhesive tape impressions (ATI) methods and fungal culture were used to identify the species of dermatophytes and Malassezia dermatitis. The results showed that Malassezia was isolated from 24 cases, including 23 Malassezia otitis and 1 Malassezia dermatitis. However, there was only one positive case with dermatophyte by two methods. Therefore, dermatophytosis could not be concluded due to the small number of positive cases. Meanwhile, Malassezia infection occurred mainly in dogs rather than cats at every age, and the infected rates were found more in exotic animals than in domestic animals and usually in males than females. The effect of treatments illustrated the significant improvement in Malassezia otitis by using Epiotic solution combined with Oridemyl ear drop. Moreover, great improvement was evident in dermatophytosis therapy with Itraconazole.

Sequencing p72 gene of field strain of African swine fever virus (ASFV) in Vietnam and generation of enhanced immunogenic fusion protein G-p72 potentially expressed as a recombinant antigen in ASFV subunit vaccine

Nhat Mai Tran — 2023-12-11

Protein p72 is the major surface protein of African swine fever virus (ASFV), which is immunogenic and can prime the host to elicit a protective immune response, while G protein is the surface glycoprotein of vesicular stomatitis virus (VSV), which is well-known to be a strong antigen to stimulate an effective humoral immunity. The aim of this study was to sequence fulllength p72 gene of a field strain of ASFV causing typical ASF in Dong Nai province in 2020 and fuse this p72 gene with VSV G gene to generate a recombinant fusion gene G-p72 that could simultaneously express both proteins and stimulate a better host immune response than p72 expression alone. The sequence of the gene showed 99.59% nucleotide sequence similarity to an ASFV isolate from China. The PCR was employed to produce the recombinant G-p72 gene, which was cloned into plasmid pET28a, followed by transformation into E. coli BL21 (DE3) for protein expression. The G-p72 expression was induced at 37°C and 28°C for 6 and 16 h, respectively. The expression showed that G-p72 was observed at 28°C for 16 h. In summary, the full length p72 gene of a field strain of ASFV was successfully sequenced and expressed as the recombinant G-p72 protein in E. coli BL21 (DE3). The expression level of the G-p72 fusion should be optimized and the immunogenicity of the recombinant protein should be examined in futher studies.

Treatment of sludge from intensive whiteleg shrimp farming using a sequencing batch reactor

Thi Que Tran Cao — 2023-12-11

The wastewater/sludge generated from the shrimp aquaculture industry contains high levels of nitrogen (N), phosphorous (P), and carbon (C). This study aimed to evaluate the efficacy of N, P, and C removal and recovery from sludge obtained during the siphoning process of intensive white leg shrimp farming by using a sequencing batch reactor (SBR) with two trials. In the first trial, reactors were operated aerobically (3 - 5 days) and anaerobically (4 - 6 days) in sequence, resulting in a total cycle time of 9 days. In trial 2, the reactors were run aerobically for the first 3, 4, & 5 days, respectively, succeeded by anoxic conditions until the end of the experiment on day 14. The results showed that the removal of total ammonia nitrogen and chemical oxygen demand was about 60 - 70%, but the treatment efficiencies of total N and P were extremely low. Moreover, the anaerobic mode improved the mineralization of P, while aerobic condition promoted nitrate production. Further studies are needed to improve the nutrient and organic removal performance of the SBR.

Optimization of essential oil extraction process from Piper nigrum L. by-products and investigation of its biological activities

Thi Hanh Phan — 2023-12-11

Black pepper (Piper nigrum L.) is an industrial crop commonly grown in Vietnam. Besides its economic value, its processing released large amounts of by-products into the environment including leaves, flatterned seeds, and seed-bearing branches. The objective of this study was to optimize the extraction of essential oil from the mixture of three black pepper by-products and evaluate its biological activities in order to exploit the potential value of the by-products. The essential oils were extracted by hydrodistillation in which the extraction conditions including extraction time, water to feed ratio, and ultrasonic pretreated time were optimized. The results showed that the highest essential oil yield was achieved after 4 h of extraction at a water to feed ratio of 10:1, and 10 min of ultrasonic pre-treament. Isospathulenol, β-elinene, caryophyllene, α-pinene, and α-copaene were identified as the main components of the essential oil as a result of chemical composition analysis using gas chromatography mass spectrometry. The essential oils exhibited 2,2-Diphenyl-1-picrylhydrazyl radical scavenging capacity with an IC50 value of 4.205 mg/mL and antibacterial capacity against four strains of bacteria, including Bacillus spizizenii, Bacillus cereus, Staphylococcus aureus and Salmonella enterica with the diameters of inhibition zone of 11.37 mm, 4.12 mm, 7.75 mm, 5.37 mm, respectively.

Effects of different doses of micro-organic and phosphorus fertilizers on growth and yield of red turmeric (Curcuma longa L.)

Thi Huyen Trang Nguyen — 2023-12-11

The objective of the study was to determine the appropriate doses of micro-organic and phosphorus fertilizers for good growth, high rhizomes yield and enhancing the economic efficiency of red turmeric cultivated in gray soil in Thu Duc city. The twofactor experiment was laid out in a split-plot design with three replications. The main plots consisted of four doses of phosphorus fertilizer as 30, 60 (control), 90, & 120 kg P₂O₅/ha. The sub-plots included three doses of micro-organic fertilizer (2, 4, & 6 tons/ha) and a control with cow dung of 10 tons/ha. A common dose of 500 kg lime, 90 kg N, 120 kg K₂O/ha was applied in all treatments. The results showed that red turmeric was applied at the dose of 120 kg P₂O₅combined with 6 tons of micro-organic fertilizer/ha exhibited the highest growth, yield and economic outcomes including a plant height of 41.2 cm, stem diameter of 16.2 mm, leaf length of 24.4 cm, leaf width of 8.5 cm, leaf count of 7.0, soilplant analysis develoment index of 35.6, the profit of VND 386.32 million/ha, and the benefit cost ratio of 2.4.