Published: 2019-12-27

Breeding new F1 hybrids cucumber for the Southeastern market in Vietnam

Phuong Nguyen, Thanh N. Nguyen, Tuong T. N. Nguyen, Thanh T. T. Nguyen, Van T. H. Duong, Truong Q. Vu, & Hung N. Pham
Electronic version: 27 Dec 2019 | DOI: 10.52997/jad.1.06.2019
Abstract | PDF (261.2K)


The objective of this study was to create new F1 cucumber varieties that would meet the demands of the regional market, in term of higher yield and reasonable cost. The study was conducted using 8 hybrid combinations: C2 x C44; C4 x C37; C12 x C44; C20 x C40; C31 x C44; C35 x C44; C41 x C52; C44 x C52 and a control variety Hunter 1.0. The growth time of hybrid combinations ranged from 64.3 to 66.7 days after sowing. The yield of the hybrid combinations ranged from 37.2 to 39.8 tons/ha. The hybrid combinations C20 x C40; C31 x C44, and C44 x C52 had a higher yield than Hunter 1.0 control. The fruit was from 17.9 to 19.7 cm long and the average weight per fruit was 156.7 - 193.3 g. The fruit flesh hardness of the hybrid combinations ranged from 30.9 to 32.0 lbf and was equal to or higher than that of the control variety.

Fish composition in Dong Nai biosphere reserve in Vietnam

Tam T. Nguyen, Loi N. Nguyen, Bao Q. Lam, Tru C. Huynh, Dang H. Nguyen, Nam B. Nguyen, Tien D. Mai, & Thuong P. Nguyen
Electronic version: 27 Dec 2019 | DOI: 10.52997/jad.5.06.2019
Abstract | PDF (317.1K)


Dong Nai biosphere reserve (DNBR) is well known for its high level of biodiversity and of global meaningful ecosystem. The fauna includes 84 species of mammals belonging to 28 families, 10 orders; 407 bird species; 141 reptile and amphibian species; 175 fish species; 2,017 insect species. The fish fauna of DNBR maintains many rare and endangered fish species recorded in the Vietnam red book and international union for conservation of nature red list (IUCN's red list) such as Scleropages formosus and many other rare fish species, such as Morulius chrysophekadion, Chitala ornata, Probarbus jullieni, Cyclocheilichthys enoplos... This study was aimed to identify fish composition distributed in DNBR. After the sampling period (01/2019 to 08/2019), a total of 114 fish species belonging to 11 orders and 28 families were recorded in DNBR. There were 09 species of fish on the list of rare and endangered fish species of Ministry of Agriculture and Rural Development of Vietnam, 3 species (Chitala ornata, Cosmochilus harmandi and Hemibagus filamentus) on the Vietnam red list book; 01 species (Ompok bimaculatus) on the IUCN's red list, 11 exotic species, 78 commercial species and 13 species having potential as aquarium fish. In addition, the study also found the first presence of a species of phallostethid, Phenacostethus smithi in DNBR.

Multiplex RT-PCR assay to differentiate genotypes of porcine reproductive and respiratory syndrome virus in swine

Nam T. Nguyen, Giao N. P. Trinh, The N. Nguyen, & Phat X. Dinh
Electronic version: 27 Dec 2019 | DOI: 10.52997/jad.2.06.2019
Abstract | PDF (3.4M)


Porcine reproductive and respiratory syndrome (PRRS) is one of the most economically important diseases to swine industry worldwide. Due to the heterogeneity of field isolates, accurate detection of the PRRS virus is a diagnostic challenge. Recently, coinfection with NA-PRRSV, EU-PRRSV and HP-PRRSV isolates continuously increases in many countries, resulting in a significant impact on PRRSV diagnostics and disease control on farms. To facilitate rapid diagnosis and reliable discrimination of NA-PRRSV, EU-PRRSV and HP-PRRSV, a multiplex RT-PCR assay was established with three pairs of primers targeting highly conservative regions of nsp2 gene with predicted multiplex RT-PCR products of 364 bp, 161 bp and 259 bp, respectively. The primer pairs were optimized to be highly specific for PRRSV genotypes and were able to detect the target gene at the limit of 102 copies/uL for each gene. Clinical samples were used to evaluate this multiplex RT-PCR in parallel with a commercial real-time RT-PCR kit. Results showed over 95.2% (20/21 samples) agreement between the mRT-PCR and the real-time RT-PCR kit. Hence, it indicated that this multiplex RT-PCR could be useful for rapid and differential diagnosis of NA-PRRSV, EU-PRRSV and HP-PRRSV in swine farms.

Influence of stocking density on water quality and growth performance of whiteleg shrimp (Litopenaeus vannamei) reared in fiberglass tanks, without water exchange

Tu P. C. Nguyen, Ha N. Nguyen, Tinh T. Phung, & Nhan T. Dinh
Electronic version: 27 Dec 2019 | DOI: 10.52997/jad.3.06.2019
Abstract | PDF (3.4M)


The present study evaluated the effects of stocking density on water quality parameters, growth performance and survival rate of white leg shrimp Litopenaeus vannamei, reared in fiberglass tanks, without water exchange. Three stocking densities (50, 100 and 200 shrimp/m2) were tested. Each treatment consisted of three replicate fiberglass tanks (500 L). The shrimp were fed ad libitum four times per day with a commercial pellet (40-42% protein). After an 8-week trial, concentrations of nutrients in the culture tanks showed an increasing linear relationship with increasing stocking density. The growth performance of shrimp in low stocking densities was significantly greater than that in high stocking densities. The results from this study demonstrate that with increasing the stocking density the production of shrimp increased but n a low final weight and survival compared to low stocking density.

Production of seaweed snack from pangasius (Pangasius hypophthalmus) fillet by-products

Kha M. Le, & Binh Q. Truong
Electronic version: 27 Dec 2019 | DOI: 10.52997/jad.4.06.2019
Abstract | PDF (346.5K)


By-products from pangasius fillet processing are a good source to create a new value-added product such as snack. In this study, the effects of seaweed ratio, seasoning ratio, drying and frying conditions on sensory, texture, water holding capacity and moisture of product were investigated to find the best quality of the product. The results showed that seaweed-added products had a better texture as compared to seaweed non-added products. However, seaweed addition > 3% weakened the product's texture. The appropriate seaweed ratio was 1%. The spice ratio (0.2% salt : 0.3% sugar : 0.1% monosodium glutamate (MSG) : 0.1% chili powder) was most  favoured. The product (size 30 x 30 mm and thickness of 2 mm) was dried at 80oC in 105 min, to the final moisture of 8.17% ± 0.04. The product was fried by shortening for 20 sec at 180oC and resulted in the highest sensory quality.

Optimization of total phenolic extraction of Chromolaena odorata leaf for antifungal activity against plant pathogens

Vinh D. H. Nguyen, Anh T. V. Nguyen, Toan Q. Truong, Ly T. P. Trinh, & Biet V. Huynh
Electronic version: 27 Dec 2019 | DOI: 10.52997/jad.6.06.2019
Abstract | PDF (1.6M)


Phenolic compounds are secondary metabolites mainly responsible for different pharmacological activities of the plant extracts. In this study, microwave-assisted extraction (MAE) variables were optimized for the extraction of the phenolic compounds from Chromolaena odorata (C. odorata) by using a central composite design (CCD) of response surface methodology (RSM). The optimized conditions were at 62oC for 3 min with solvent to feed ratio of 14:1 (mL/g) and ethanol concentration of 50% (v/v). The highest yield of total phenolic compounds was 75.76 mgGAE/g. Ethanol extract clearly showed antifungal activity through antifungal index. The antifungal effect Phytophthora capsici, Fusarium oxysporum and Colletotrichum siamese were 79.07%, 78.66% and 78.42%, in 0.5% of ethanol extract, respectively.

Spray-drying microencapsulation of β-carotene by polysaccharide from yeast cell walls

Hien T. Do, Tuyen C. Kha, & Trang P. P. Huynh
Electronic version: 27 Dec 2019 | DOI: 10.52997/jad.7.06.2019
Abstract | PDF (421.1K)


It is well known that β-carotene plays an important role in human health. However, it is susceptibly degraded by environmental conditions including temperature, light and oxygen, due to its natural structure of conjugated double bonds chain. Polysaccharide (PS) from the yeast cell walls has appeared to be an excellent choice of encapsulating agent that can be used to encapsulate biologically active substances. Objective of this study was to investigate the effects of PS concentration (20, 30, 40 and 50%) compared to MD, high pressure homogenization time (5, 10, 15, 20 min) and inlet air temperature of spray drying (130, 140, 150, 160°C) on microencapsulation yield (MEY), microencapsulation efficiency (MEE), moisture content (MC) and antioxidant capacity. The results showed that the highest values of MEY (354.4 µg/g) and MEE (90.2%), the low value of MC (7.0%) and antioxidant capacity (69.07%) were successfully obtained at PS concentration of 30% (w/v), homogenization of 15 min and inlet air temperature of 150°C. Under those conditions, the encapsulated β-carotene powder was examined by scanning electron microscopy (SEM) and it is confirmed that the microparticles had various sizes which are a typical characteristics of spray dried powders, spherical shapes and were free of cracks and pores. As a result, it can be concluded that β-carotene was successfully encapsulated in the PS and MD matrix and could then be easily incorporated into various foods.

Effects of different extraction methods on the recovery yield of bixin from annatto seeds (Bixa orellana L.)

Chuyen V. Hoang, Thuy T. Ha, & Eun Jong-bang
Electronic version: 27 Dec 2019 | DOI: 10.52997/jad.8.06.2019
Abstract | PDF (460.1K)


Bixin is a principal color component of annatto pigment which is obtained from the seed coat of Bixa orellana L., a tropical shrub. The extraction yield of bixin from annatto seeds using acetone, soybean oil and sodium hydroxide solution with different extraction conditions were investigated in this study. The extraction time, temperature, solid-liquid ratio and light exposure showed significant effects on the bixin yield. The extraction using soybean oil had the lowest bixin yield followed by the extraction using sodium hydroxide solution. The extraction using acetone resulted in the highest extraction yield (68.1%) after only 40 min. The extraction using soybean oil at 100oC led to two-fold bixin yield compared to that operated at 80oC while the mild temperature (50oC) was found to be the most suitable for the extraction using sodium hydroxide solution. The exclusion of light exposure by covering extraction beakers with aluminum foil could significantly improve the bixin extraction yield due to the reduction in bixin degradation. Therefore, the extraction using acetone avoiding light exposure is suggested for recovering bixin from annatto seeds.