Published: 2021-10-30

Trial on artificial breeding and laviculture of giant razor clams (Cultellus maximus Gmelin, 1791)

Hong Nguyen, & Nhan T. Dinh
Electronic version: 29 Oct 2021 | DOI: 10.52997/jad.5.05.2021
Abstract | pdf (4.8M)

Abstract

The study was carried out with the aim of determining the reproductive parameters and performing the rearing of giant razor clams (Cultellus maximus Gmelin, 1791) at larval stage and postlarval stage with different diets. The results showed that the spawning rate was 62.22 ± 3.85%, the fecundity was 7.98 ± 0.67 million eggs/female, the relative fecundity was 48,081 ± 5,826 eggs/g female, the fertilization rate was 42.67 ± 4.47%, and the hatching rate was 44.19 ± 4.02%.  The rearing at larval stage with different diets of algae was investigated ((T1.1): Nanochloropsis oculata + Isochrysis galbana; (T1.2): N. oculata + Chaetoceros muelleri; and (T1.3): N. oculata + Isochrysis galbana + C. muelleri). The results showed that T1.3 gave the survival rate, length and width of larvae, reaching 5.3 ± 0.91%; 1525.60 ± 48.90 μm and 918.20 ± 28.00 μm, respectively. The parameters obtained from T1.3 was significantly higher (P < 0.05) than that of T1.1 and T1.2. The rearing at postlarval stage with different diets was also studied as follow: (T2.1): N. oculata + I. galbana + C. muelleri; (T2.2): using commercial feed (Lansy and Frippak); and (T2.3): combination of 50% of T2.1 + 50% of T2.2. The results showed that T2.1 gave the survival rate, growth in length and width of postlarvae, reaching 11.83 ± 3.89%; 5.72 ± 0.61 mm and 3.31 ± 0.14 mm respectively. Growth parameters of T2.1 were significantly higher (P < 0.05) compared to that of T2.2 and T2.3.

Effects of low-density lipoprotein extracted from egg yolk on preservation of chilled canine semen (4oC)

Van . T. Nguyen, Anh T. P. Nguyen, Huy D. Nguyen, Phuc L. G. Ha, & Khanh T. V. Doan
Electronic version: 29 Oct 2021 | DOI: 10.52997/jad.2.05.2021
Abstract | pdf (620.8K)

Abstract

Low-density lipoprotein (LDL) derived from hen egg yolk has beenconsidered an important component in the storage of canine semen;however, in Vietnam, there have not been many studies regardingthis topic. Therefore, this study aimed to evaluate the effectivenessof LDL in the preservation of canine chilled semen in Vietnam. Theassessment of semen samples was based on four criteria: storage time,motility, absolute viability, and integrity of acrosomal membrane atmotility rate 0.9; 0.5 and 0.3. The semen samples collected weredivided into three equal parts, each was then diluted with threedifferent extenders and stored at 4oC. The extenders were LDL +basic extender (LDL), egg yolk + basic extender (EY), and basicextender (C).The storage time of canine semen was recorded from the beginningof monitoring until the motility decreased to 0.3. The storage timeof the three extenders was in the order of EY > LDL > C, with 108h, 60 h, and 48 h, respectively. The absolute viability of fertilizablesperm (Sa5) in the extender was EY (768), LDL (423) and C (280),which was significant (P < 0.001). The percentage of viable spermwith intact acrosome membrane at motility time A = 0.9 in LDLwas 59.31%, higher than that in EY (30.99%). In the storage periodfrom A = 0.9 to A = 0.5, the acrosome loss percentage of both EYand LDL decreased equally (7.30% and 7.23%), but the storage timeof EY (84 h) was longer than that of LDL (48 h).In conclusion, the EY gave a longer storage time, higher absoluteviability and longer maintain percentage of viable sperms and intactacrosome membrane compared to the LDL. However, within the firsthours of storage, the percentage of viable sperm and intact acrosomemembrane in the EY was lower than that in the LDL. Therefore, topreserve canine semen for a short time (less than 48 h), the LDLextender should be used for better effectiveness.

Assessment of the immune responses of macrophages in selective breeding pangasius families (Pangasianodon hypophthalmus) resistant to enteric septicemia of catfish (ESC)

Dung T. P. Tran, Sang V. Nguyen, Phuong . H. Vo, Phuc H. Tran, Quan T. T. Huynh, & Thinh H. Nguyen
Electronic version: 29 Oct 2021 | DOI: 10.52997/jad.4.05.2021
Abstract | pdf (6.1M)

Abstract

This study aimed to evaluate the non-specific immune responses of macrophages in two selective breeding pangasius family groups: high disease-resistant (A) and low disease-resistant (B) to Enteric Septicemia of Catfish (ESC) caused by Edwardsiella ictaluri. Fish were sampled at five different time points after infection with the bacteria E. ictaluri including before the infection process, 24hpi, 48hpi, 264hpi and 312hpi. There were 372 samples including 192 samples of fish in group A and 180 samples in group B. All of them were used to analyze the amount of melano-macrophage centers in the tissues of liver, kidney and spleen; phagocytosis activity (PA) and phagocytosis index (PI) of the anterior kidney macrophages. Results showed that (1) the number of melano-macrophages of group A fish was higher than that of group B at survey points during the challenge and the difference was significant at 48hpi; (2) PA and PI of group A were higher than that of group B in the period from 48 to 264hpi, specifically, the PI of group A was higher than that of group B, which was statistically significant at 48hpi. The results of this study showed that the differences in non-specific immune responses through melano-macrophages can improve the survival rate and life span of the high disease-resistant family compared to the low disease-resistant family after the challenge with Edwardsiella ictaluri.

Antibiotic resistance of Escherichia coli isolated from the white-leg shrimp (Litopenaeus vannamei) collected from Binh Dien Agricultural Wholesale Market

Hue N. D. Truyen, Thanh Khuu, Nhu Do, & Thu Tran
Electronic version: 29 Oct 2021 | DOI: 10.52997/jad.6.05.2021
Abstract | pdf (3.6M)

Abstract

This study was conducted to determine the rate of antibiotic resistance, multiple antibiotic resistance of 60 E. coli strains isolated from white-leg shrimp (Litopenaeus vannamei) collected from Binh Dien Agricultural Wholesale Market in Ho Chi Minh City. Should have a short description how to perform the study here Within10 examined antibiotics, those E. coli strains showed a high resistant level to ampicillin (96.7%), streptomycin (70.0%), kanamycin (66.7%), nalidixic acid (60.0%), tetracyclines và trimethoprim/sulfamethoxazole (56.7%), ciprofloxacin (61.7%), chloramphenicol (43.3%). The percentage of multidrug-resistant strains (from 5 to 10 tested antibiotics) was 55%. All isolated  strains were insensitive to all 10 tested antibiotics. Four strains (6.7%) were found to be resistant to all these antibiotics. So what is the conclusion?  

Detection methods of Acute Hepatopancreatic Necrosis Disease (AHPND) and its mutant (mutant-AHPND) in shrimp

Dung Mai, Binh Huynh, Hoan Nguyen, & Hieu V. Tran
Electronic version: 29 Oct 2021 | DOI: 10.52997/jad.3.05.2021
Abstract | pdf (7.9M)

Abstract

Acute Hepatopancreatic Necrosis Disease (AHPND) is a globally seriousthreat, especially for Vietnam shrimp culture since its first discovery inChina in 2009. This disease is caused by toxin-carrying bacteria Vibrioparahaemolyticus whose plasmid encodes for a binary toxin ToxA andToxB. The disease has a mortality rate of up to 100% after 3 - 5 dayspost-infection and fast spread among shrimp culturing regions. In 2017, abacterial strain V. parahaemolyticus XN87 containing plasmid with mutant toxA and normal toxB genes was found. In this mutant form, shrimpdid not show hepatopancreatic necrosis symptoms, but the early mortalityrate in shrimp was still up to 50%. This mutation was called mutantAHPND. Depending on different purposes and subjects, the correspondingdetection method will be selected. Understanding the specific nature andapplication of each method is essential for the prevention and treatment ofAHPND disease in shrimp to minimize economic losses for shrimp farmers. In this review, we summarized AHPND-detected methods based ondetecting genes (toxA and toxB) or protein (ToxA and/or ToxB toxins) aswell as a method for early detection of the mutant-AHPND. Eventually,potential detection methods are also addressed and discussed.

Isolation and selection of carotenoid-producing bacteria from marine environment and determination of carotenoid extraction condition

Cuc Le, Hoa Le, Trang Tran, Vi Van, Phong Nguyen, & Thanh T. L. Bien
Electronic version: 29 Oct 2021 | DOI: 10.52997/jad.7.05.2021
Abstract | pdf (5.6M)

Abstract

The carotenoid is a natural pigment group, which is gradual of interest because of its essential biological activities and great production potentials such as using low-cost material and easy to apply on a large scale. For further development of natural carotenoid products, in this study, fourteen yellow, red, and orange pigment-producing marine bacterial strains were isolated from 25 seawater samples collected along coasts of Phu Quoc island (Kien Giang province), Vung Tau City (Ba Ria – Vung Tau province), Can Gio district (Ho Chi Minh city), and Thang Binh district (Quang Nam province). These isolates were identified belong to seven genera Micrococcus, Kocuria, Microbacterium, Brevibacterium, Bacillus, Rhodococcus and Exiguobacterium with 96.7% - 100% of 16S rRNA sequences identity. Based on carotenoid producing ability and UV-absorbance profile, three of the isolates including Micrococcus sp. 64A3a (yellow), Exiguobacterium sp. YT09 (orange) and Rhodococcus enclensis strain RSA3 (red) were selected for investigation of carotenoid extraction conditions. Methanol at concentration of 100% with ratio of 1 g bacterial cells/10 mL methanol is suitable conditions for extraction of red, orange and yellow pigments from the isolates.

Survey of lighting systems and aesthetic illumination design for various major parks in Ho Chi Minh City

Thuy T. Vuong, Tien Duong, Nguyen Vo, Nghia Dang, Khanh Nguyen, & Truong Ha
Electronic version: 29 Oct 2021 | DOI: 10.52997/jad.8.05.2021
Abstract | pdf (7.3M)

Abstract

The study was carried out from August 2019 to August 2020 at five major parks in Ho Chi Minh City. We aimed to survey the lighting system including bulb types, lamp types, illumination type, and average horizontal illuminance. The study was carried out by several methods such as a questionnaire of the characteristics of the lamp, observing, measuring, analyzing, synthesizing data, and evaluating. We divided each park by area, for example, main gate, side gate, main axis, branch road, lawn, activity area for investigation. The result showed that the parks having LED and HQ compact bulbs, which were popular chandeliers. Most parks had direct lighting to provide panoramic illumination, but did not reach the average horizontal illuminance. We propose an aesthetic illumination design for the central area of ​​the park with ideas from the history of the park's formation and development. The research results contribute to the improvement of the lighting system for the parks in Ho Chi Minh City.

Selection of sugarcane varieties (Saccharum officianum L.) with high yield and quality, suitable for cultivation conditions in Binh Duong province

Tuan Tran, & Hien Pham
Electronic version: 29 Oct 2021 | DOI: 10.52997/jad.1.05.2021
Abstract | pdf (391.2K)

Abstract

The objective of this research was to select sugarcane varieties with yield > 60 tons/ha and commercial cane sugar (CCS) > 11, to recommend to put into production in Binh Duong province. This study was carried out in Phu An commune - Ben Cat town - Binh Duong province, from January 2020 to December 2020. The experiment was designed in a split plot (SPD) with 3 replications and 2 factors, including irrigation as main-plot factor with 2 levels as irrigated and rain-fed (non-irrigation) conditions, and sugarcane varieties as subplot factor with 10 VN varieties named VN14-13-4, VN14-22-5, VN14-23-13, VN14-37-2, VN14-41-8, VN14-45-3, VN14-49-6, VN14-74-1, VN14-87-11 and VN14-89-3. The controls consisted of drought tolerance VN84-4137 and drought sensitive KU60-1 varieties. The results showed that VN14-37-2, VN14-22-5, VN14-23-13, and VN14-87-11 were promising sugarcane varieties, suitable for cultivation conditions in Binh Duong province. Cane yield of these varieties ranged from 69.67 tons/ha to 75.50 tons/ha in irrigated condition. In the rain-fed condition the yields obtained were from 55.50 tons/ha to 61.17 tons/ha. Their average yield was above 62 tons/ha and equivalent to control VN84-4137. Sugar contents of these varieties were above 11.90 CCS. The corrected yield for 10 CCS ranged from 86.83 to 94.78 tons/ha in irrigated condition and 66.10 to 73.99 tons/ha in rain-fed condition.