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• Estimating Sperm Motility of WaigieuSeaperch(Psammopercawaigiensis) Preservedin Refrigerator throughout the Reproductive Season

  Le Minh Hoang, Pham Quoc Hung

  Received: 26-01-2016 / Accepted: 06-06-2016

   Abstract PDF (VIETNAMESE)

  The objectives of this study were to find the optimalsperm dilutionandgentamycin concentration forWaigieu seaperch,Psammoperca waigiensis,chilled sperm preservation throughout the spawning season. The semen werediluted at 1:1, 1:3, 1:5 and1:7 in artificial seminal plasma. Gentamycin was added at concentration of 100, 200 and300 ppm. Semen dilution at1:3and addition of 200ppm gentamycin with sperm collected at the beginning spawning season and the middle spawning season and dilution ratio of 1:5 with300ppm gentamycin with sepermcollected at end spawning seasonyielded highest sperm motility.

• Study on Extraction and Separation of Anthocyanin from Hibiscus Sabdariffa Calyx. Application to Produce the Rapid Indicator Paper of Detecting the Borax in Food

  Nguyen Thi Hien, Nguyen Thi Thanh Thuy, Nguyen Thi Loan

  Received: 29-05-2012 / Accepted: 12-08-2012

   Abstract PDF (VIETNAMESE)

  The extraction and purification of anthocyanin pigments from calyx of Hibiscus sabdariffa, and its use as potential rapid indicator paper for detecting the borax in food were investigated. By using the colour comparison and the differential pH methods, the optimal conditions for pigment extraction were identified as follows: ethanol solvent to water is 50:50 with supplement 1% HCl; the ratio of solvent per raw-material is 14 ml/1g; extracting duration is 6 days. By fractional extraction method, the crude anthocyanin pigments are isolated from extracts of Hibiscus calyx. The concentration of pigments in the dry and fresh material was 15.2% and 1.06%, respectively. The acidity of the dry ingredients is 3.37 mldH+ /1g of raw material, the acidity of the dry pigment is 3.83 mldH+/1g of colour substance, respectively 0.58 mldH+ /1g dry material and the acid reduced 83%. By surveying several conditions for production of the indicator paper, the appropriate parameters are selected with color dilution of 1gram of dry colour substance to 400ml distilled water ratio; duration of color impregnated on paper is 120 seconds; the duration of indicator paper exposure to food (or food fluid) is 90 seconds. A minimum level of the indicator paper for detecting the borax is identified as 40 mg/1 kg of food. This result has shown that the minimum detectable limit is equivalent to turmeric paper. As for sensitivity, when testing on a number of food materials, the similar results were also been obtained.

• Effects of Cooling Methods on Sperm Quality in Boar Semen Preservation at Low Temperature

  Bui Huy Doanh, Dinh Thi Yen, Cu Thi Thien Thu, Nguyen Ngoc Kien, Nguyen Thi Tuyet Le, Dang Thai Hai, Pham Kim Dang

  Received: 31-08-2020 / Accepted: 08-12-2020

   Abstract PDF (VIETNAMESE)

  This study was conducted on 720 semen samples of six Duroc boars to evaluate the effects of the different cooling methods on semen quality when stored at low temperatures in an extender without antibiotics. Semen was diluted in a modified BTS extender without antibiotics. Semen samples were cooled from 30°C to 5°C using five different cooling rates before stored at 5°C. Diluted semen was investigated after 24h, 48h, 72h and 120h of preservation. The results showed that: the lowest cooling rate sample (5-A4: 2h at room temperature, then stored at 10°C for 3 h) had sperm motility, abnormal acrosome, as well as morphology in different days of storage, which did not differ from semen samples stored at 17°C (P >0.05). Rapid cooling rate and direct storage at 5°C (5-A0 stored immediately at 5°C after dilution) were reduced sperm motility as well as increased abnormal spermatozoa (P

• Establishing Virus Neutralizing TestPorcine Epidemic Diarrhea Virus (PEDV)using Isolated Field Strains in the North of Viet Nam

  Nguyen Thi Bich, Tran Van Khanh, Nguyen Thanh Ba, Chu Thi Thanh Huong

  Received: 18-05-2020 / Accepted: 23-06-2020

   Abstract PDF (VIETNAMESE)

  The study aimed to establish a virus neutralization test for field isolated virus, create a tool for assessing the protection of vaccines against pathogenic porcine epidemic diarrhea virus (PEDV) strains in Vietnam. By using DMEM medium free calf fetal serum (FBS) and without trypsin for dilution sample preparation/viral suspensions, and the maintenance medium containing 8 µg of trypsin/ml, the virus neutralization test and evaluation of neutralizing antibodies by immunochemical staining on monolayer cells were optimized. The results showed that the virus neutralization test for field isolated virus with the sensitivity of 87.46% and specificity 98.18% with compared to ELISA kit. It also pointed out that the virus neutralization test could be applicated to detect fluctuation of PEDV neutralization antibody in colostrum and serum of mother and piglets.

• Assessment of the Possibility White Spot Virus Infectionfrom Red Fiddler (Ucasp.) to White Shrimp (Litopenaeus vannamei)

  Truong Thi My Hanh, Huynh Thi My Le, Pham The Viet, Phan Thi Van

  Received: 28-02-2017 / Accepted: 10-04-2017

   Abstract PDF (VIETNAMESE)

  White spot syndrome virus (WSSV), the causative agent of white spot syndrome in shrimp, has a wide host range includingcrabs, zooplankton (Copepods), molluscs, poultry and polychaete.Ucasp.isa common fiddler living in intertidal land, estuary and sourcewaterused for settling pond of shrimp farmsin Nam Đinh, Nghe An and Quang Ninh. WSSV, an important viral pathogen of the shrimp, can replicate in crustacean species,therefore, it is a potential vector for virus transmission. The major aim of this study was to determine whether WSSV can be replicate on Ucasp and transmitted from Ucasp. to shrimp (Litopenaeus vannamei) through water environment. Uca sp. wasinfected withWSSV by injecting suspension containing WSSV in dilution 10-2on the second leg. Results showed that, WSSV was detected in infected fiddler in experimentby PCR method after 107 hours of infection. WSSV was transmitted from Ucasp. to shrimp through water environment horizontally after 83 hours of exposure to Ucasp. carrying WSSV. Our findings support the contention that Ucasp. was a potential vector for virus transmissionandcan be a source of WSSV infection of culture shrimp.