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Current Status ofand Solutions to Accelerating Administrative Procedure Reform for Investment in Hung Yen Province

Do Minh Tri, Bui Bang Doan
Reforming administrative procedures is an important content of the overall public administration reform program. Because reforming administrative procedures relates to individuals, businesses and organizations in social life, it is of great concern and considered as breakthrough content in innovating state administration during past few years. As a province with many advantages in the process of integration and development, Hung Yen soon implemented public administration reforming program, especially the reform of administrative procedures. Information related to administrative procedure reform for investment was gathered through surveillance of the enterprises and stakeholders, group survey and panel discussion. Data were analyzed using descriptive and comparative methods. The paper has clarified the current status of the administrative procedure reform and proposed the key solutions to accelerate administrative procedure reform to attract investments in the near future.
Development of Pig Farming for Porkin Thanh Hoa Province

Pham Xuan Thanh, Luong Thi Dan, Mai Thanh Cuc

Received: 03-06-2014 / Accepted: 08-09-2014
Pig farming for pork or pork productionis an important industry of the agricultural sector in Thanh Hoa province. In recent years, thanks to well management of local governments, pig rearing in the province has gradually developed; nevertheless, it is not really sustainable. Data gathered from statistical reports, especially from published statistical data on pig farming in general and pig farming for pork in particular were analyzedto evaluate the status and advantages anddisadvantages of pork production in the province. Some solutions for future pork production were recommended..
Môhìnhhóaphảnứngcủatáođượcbảoquảntrongkhíquyểnđiềuchỉnhcónồngđộoxy thấp

Tran Thi Dinh, Bert E Verlinden, Bart M Nicolai

Received: 05-07-2014 / Accepted: 15-08-2014
Một kỹ thuật mới dựa trên phổ huỳnh quang diệp lục HarvestWatchTM đặt trong môi trường bảo quản khí quyển điều chỉnh có nồng độ oxy thấp được thử nghiệm trên giống táo Greenstar để phát hiện thời điểm nồng độ oxy giảm quá thấp gây bất lợi cho hoạt động sinh lý của quả. Mục tiêu của nghiên cứu này là phát triển mô hình để dự đoán phản ứng của táo bảo quản trong môi trường có nồng độ oxy rất thấp. Để đạt được mục tiêu này mô hình hồi quy tuyến tính được xây dựng dựa trên số liệu thực nghiệm để diễn tả sự phụ thuộc của giá trị chênh lệch của chlorophyll fluorescence (Δ Fα) đối với các nồng độ oxy bất lợi. Mô hình tuyến tính ARX được đề xuất để dự đoán giá trị chlorophyll fluorescence (Fα) ở các mức ức chế khác nhau. Kết quả nghiên cứu cho thấy hệ thống HarvestWatchTM có thể được phát triển để duy trì tối đa chất lượng quả táo khi bảo quản bằng công nghệ điều chỉnh khí quyển động.
EFFICACY OF PRAZIQUANTEL AGAINST EXTERNAL PARASITES INFECTING FRESHWATER FISH

Truong Dinh Hoai, Kim Van Van

Received: 04-03-2014 / Accepted: 13-08-2014
Praziquantel has been used to control external parasites on marine fish but there is little data about its effect on treating external parasites infecting freshwater fish. This study examined whether praziquantel was able to control external parasites on freshwater fish in Vietnam. Four external parasites, monogenean trematode (Dactylogyrus sp.), parasitic Crustacea (Lenear sp.) and two ciliated Protozoa (Trichodina sp. and Epistylis sp.) naturally infecting Grass carp (Ctenopharyngodon idella), Common carp (Cyprinus carpio) and Tilapia (Oreochromis niloticus), respectively, were experimentally treated. Infected fish were exposed to praziquantel in baths for periods of 1, 3, 24, 48 and 72 hrs at each of five different concentrations 2.5, 5, 7.5 and 10 mg/l with a control (0 mg/l) treatment. Doses of 7.5-10 mg/l praziquantel administered for 1-3 h for fish infected with two ciliated Protozoa and 24-72h for the other two parasites were effective in eliminating all parasites without killing the fish. Thus, praziquantel of doses at 7.5-10 mg/l immersed within 72h duration is an appropriate therapy for simultaneous treatment of a number of external parasites of freshwater fish. The results have important implications in the management of fish health in current aquaculture systems.
Performance and Meat Quality of Hybridcombinations between Dom and T14 Ducks

Dang Vu Hoa, Dang Thuy Nhung, Nguyen Duc Trong, Hoang Van Tieu

Received: 03-07-2014 / Accepted: 13-08-2014
The experiment was conducted at Dai Xuyen Duck Research Center - NIAH to evaluate the production performance and meat quality of duck hybrid combinations between Dom and T14 - super meat line. Four groups of ducks: Dom, crossbreds PT (Dom father, T14 mother) and TP (T14 father, Dom mother) and T14, were each fed with 100 individuals from hatching to 10 weeks of age and body weight and FCR were recorded. At 8, 9 and 10 weeks of age, each group of 6 individuals was killed to assess carcass and meat quality criteria. The results showed that the above mentioned groups reached the body weight at 8 weeks of age: 1660, 2300, 2220 and 2890g per head, respectively; at 9 weeks of age: 1730, 2380, 2340 and 3030g per head, respectively and at 10 weeks of age 1880, 2560, 2530 and 3210g per head, respectively. The FCR increased with increased weights, lowest in T14, highest in Dom; PT and TP crossbreds were similar. From 8 to 10 week of age, the dress proportions of all groups had not changed apparently, in which thigh meat reduced and breast meat increased. The breast and thigh meats of all 4 groups had a high rednees. The slaughter ages increased, the brightness, yellowness and dehydration ratio after processing increased. There was no much difference between four duck groups on the color, tenderness, and dehydration ratio after processing.
Evaluation of Diversity and Characteristics among Common Beans (Phaseolus vulgarisL.) Exotic Germplasm in Vietnam Condition

Pham Thi Ngoc, Do Thi Du, Nguyen Thi Hue, Pham Thi Le, Vu Van Liet

Received: 11-07-2013 / Accepted: 07-05-2014
The agronomical characteristics and heat tolerance of twenty nine common bean accessions from USA were evaluated in two seasons: late spring and winter seasons in 2012 in Gialam, Hanoi. Most of the accessions showed short growth (55 to 80 days) suitable to cropping pattern of the Red RiverDdelta. There was a large variation in agronomical characteristics, such as plant height, number of leaves and branches, stem and flower color, fruit shape and grain size. The twining bean accessions had plant height from 180.5 to 306.0 cm while bush type accessions were three to five times shorter. Four accessions viz.CV44, CV54, CV59 and CV79 were heat torelant. Genetic similarity based on morphological characteristics and agronomic performance classified accessions into four separate groups with similarity coefficient of 0.18. Some accessions such as CV56 (107.52g), CV65 (145.91g), CV67 (116.28g), CV73 (191.35g), CV83 (117.28g), CV85 (117.77g) in green bean group and CV76 (52.0g) and CV77 (54.89g) in dry bean group had high yield in the winter season only. These accessions are potentialy useful for breeding programme with high yield.
Study into Application of Relative Valuation Model for Listed Companies in Ho Chi Minh Stock Exchange

Nguyen Thi Hoang Giang, Bui Thi Hong Nhung

Received: 27-05-2013 / Accepted: 24-04-2014
As one of the two most popular valuation models in the world, relative valuation is closely related to empirical evidence of stock return predictability. Applying this model to 307 listed companies in Ho Chi Minh Stock Exchange (HOSE) using two multiples, P/B and P/E, the study showed that investment strategies using industry’s P/E is the most successful, while those based on P/B are not, despite various modifications of peer company choices. However, in evaluating the predictive power of these multiples, P/E appeared to be statistically insignificant and P/B had an unexpectedly positive correlation coefficient with stock price fluctuations. This result suggested critical implications in establishing stock returns predictors in the research context of Vietnam stock market.
Study on TheExtraction Technology of Essential Oil from Perilla Leaves

Nguyen Thi Hoang Lan, Bui Quang Thuat, Le Danh Tuyen, Ngo Thi Huyen Trang, Do Thi Trang

Received: 04-04-2014 / Accepted: 13-05-2014
Perilla frutescensis widely cultivated as a source of spices and medicine. The present study was carried out identify the most suitable oil extraction method and to optimize the extraction technique. Three extraction methods were used: static extraction at room temperature for 24 hours, dynamic extraction at 50oC with stirring speed of 400 rounds/min for 1 hours, and Soxhlet extraction at 80oC for 7 hours. Among three extraction methods, dynamic extraction was found as the most suitable method to extract essential oil from perilla leaves. For this method, fresh perilla leaves were withered in natural conditions to 20% moisture and were crushed to particle size of 2-3mm in diameter. The ground materials were then extracted 3 times by 96% ethanol ata ratio of 1 g ground leaves to 18mL solvent. Extraction was carried out at 50oC for12 hours. After extraction, the extract was evaporated by rotary vacuum equipment to obtain essential oil. The essential oil obtained has perilla flavor characteristics with major components comprising of 37.38% perilla aldehyde, 26.39% myristicine and 5.95% limonene, which can be used as fragrance in food and pharmaceutical products
Changes inAgricultural and Forest Land Usein DaknongProvincefrom 2000 To 2012

Luu Van Nang, Nguyen Thanh Lam, Tran Duc Vien

Received: 12-11-2013 / Accepted: 28-12-2013
Dak Nong Province, a newly established province in the central highland, has on going processes of landuse changes in both agriculture production and forestry land from 2000 to present. The research showed that the total area of forest land lost at this stage is estimated at 131.725 ha (approximately 20% of total natural area of the province). This is an alarming figure due to the specific geographic location and, the deforestation in Dak Nong will affect the ecological environment not only in the province but also the surrounding regions in Central and Southeast provinces. Investigation through household interviews and working with related departments at provincial and district levels as well as consulting the scientists, the research identified the trend of arable and forest land use as well as the main cause of losing forest in the period from 2000 to 2012 . The solutions toof agricultural and forest land use in Dak Nong province were also prposed.
Production Lily Bulblets by Scale in the North of Vietnam

Nguyen Van Tinh, Nguyen Xuan Ket, Dang Van Dong, Hoang Minh Tan

Received: 16-09-2013 / Accepted: 26-12-2013
Lily can be propagated by sexual and asexual means. There are many asexual propagation methods to produce bulbs: separation of younger, small bulbs from mature bulbs, offsets growing from parent plants, bulbils formed in the leaf axils, tissue culture or by scales.. The propagation by scaling method is used mainly in the countries producing lily bulbs. In Vietnam, this propagation method is hardly applicable. Therefore, this study aimed at finding the technical parameters for production of small bulbs by bulb scales. The most suitable main bulb perimeter to take scales is 20-22 cm. The scales are placed between land and coir layers to obtain high multiplication rate and quality of small bulbs. Cold treatment (50C) of small bulbs most rapidly transformed the starch and sugar into reducing and soluble sugar during the first 40 days of cold treatment. The results may serve as basis for further research in the production of lily bulbs by scaling method.
Effect of Drought Treatment on Photosynthesis and Dry Matter Accumulation in Some Sorghum Varieties (Sorghum bicolor(L.) Moench)

Doan Cong Dien, Tang Thi Hanh, Pham Van Cuong

Received: 25-10-2013 / Accepted: 26-12-2013
A pot experiment was conducted in the green house in 2011 spring cropping season at Hanoi University of Agriculture to determine the effects of drought stress (-60 kPa) on photosynthetic rate and dry matter accumulation in vegetative stage of some sorghum cultivars (Sorghum bicolor (L.) Moench). Carbon exchange rate (CER), chlorophyll content, Fv/Fm value, leaf area and dry matter accumulation (DM) decreased in all sorghum varieties under the drought treatment. There were positive relationships between CER and stomatal conductance and between CER and transpiration rate. These relationships were closer in drought treatment than those in control. Among 10 sorghum varieties, CL88 showed the best recovery for CER. Besides, CL09 exhibited the highest value of DM, chlorophyll content and Fv/Fm at recovery stage.
Thu hồi protein và lipit từ đầu cá ngừ bằng enzyme protease công nghiệp

Nguyen Thi My Huong

Received: 28-09-2013 / Accepted: 22-12-2013
Sự thu hồi protein và lipit từ đầu cá ngừ vây vàng theo phương pháp thuỷ phân bằng enzyme đã được nghiên cứu. Sự thuỷ phân đầu cá ngừ được thực hiện bằng Protamex 0,5% ở nhiệt độ 45°C, không điều chỉnh pH, trong thời gian 120 phút, tỉ lệ nước/nguyên liệu là 1/1 (ml/g). Hiệu suất thu hồi nitơ, thành phần axit amin của sản phẩm thuỷ phân protein, hiệu suất thu hổi lipit và thành phần axit béo của dầu cá thu được từ sự thuỷ phân đầu cá ngừ đã được xác định. Kết quả đã chỉ ra rằng sau 120 phút thuỷ phân, hiệu suất thu hồi nitơ và lipit lần lượt là 70,3% and 65,4%. Sản phẩm thuỷ phân protein từ đầu cá ngừ vây vàng có hàm lượng protein 80%, lipit 1,3% và tro 7,9%. Sản phẩm thuỷ phân protein có hàm lượng axit amin không thay thế cao (33,67%). Dầu cá thu được từ sự thuỷ phân đầu cá ngừ giàu axit béo omega 3 (18,99%), đặc biệt axit docosahexaenoic (DHA) và eicosapentaenoic (EPA). Hàm lượng axit béo omega 6 là 4,37%. Các axit béo có hàm lượng cao trong dầu đầu cá ngừ là palmitic (29,75%), oleic (16,76%) và docosahexaenoic (14,56%).
Effect of Halothane Genotype, Gender on Carcass Characteristics and Meat Quality of Stress Negative Piétrain Pigs

Ha Xuan Bo, Do Duc Luc, Dang Vu Binh

Received: 10-09-2013 / Accepted: 25-11-2013
This study was carried out at the animal farm of Hanoi University of Agriculture from August 2012 to April 2013 to evaluate effects of halothane genotype (CC and CT) and gender (intact males and gilts) on carcass characteristics and meat quality of Piétrain stress negative pigs. The backfat thickness, depth of longissimus dorsi muscle and lean meat percentage at 7.5 months were collected from 83 pigs (31 females and 52 intact males). Data on carcass performance were collected from 43 pigs (28 females and 15 intact males). The organoleptic quality of longissimus dorsi muscle was determined from 35 samples (19 females and 16 intact males). For meat chemical compositions, 24 samples (14 females and 10 intact males) were analyzed. Slaughter weight (88.75 kg), carcass weight (58.40 kg), eye muscle area (57.54 cm²), backfat thickness (9.26 mm) and depth of longissimus dorsi muscle (58.01 mm) of gilts were higher than those of intact males (81.29 kg, 52.77 kg, 51.04 cm², 8.01 mm and 52.76 mm). Killing out percentage, carcass percentage and carcass length were similar between gilts and intact males (P>0.05). The pH of longissimus dorsi muscle at 24 hours post mortem between gilts (5.34) and boars (5.50) were significantly different (P<0.001). Gilts had more lipid content than intact males (P<0.01). Halothane genotype did not affect carcass characteristics, meat quality and meat chemical composition (P>0.05). The results indicate that Piétrain stress negative pigs had high carcass percentage and good meat quality. Individuals with halothane genotype CC and CT can be choosen for the breeding without affecting the carcass performance and meat quality. Carcass percentage and pH45 of longissimus dorsi muscle of gilts were higher than those of intact boars.
The Current Situation and Economic Efficiency for Using Cultivative Land in Tu KyDistrict, Hai Duong Province

Dao Duc Man, Nguyen Tat Canh

Received: 05-09-2013 / Accepted: 23-09-2013
The study evaluated the curent status of agricultural land use models as well as economic effectiveness of land use types TheGAMS multipurpose mathematic model was used to determine land use typeswith high economic efficiency to serve as basis for developing land use guidelines until 2020 in Tu Ky district. In 2010, there were 29 land use formswithin three main land use types in the district. The economic efficiency of land use for rice cultivation was shown to be lower that land use for non-rice crops. Based on GAMS model with varying food production and investemnt as variables, potential land use types were proposed.
Some Factors Which Influence Management of Agricultural Land Use in Sontay Town, Hanoi City

Bui Tuan Anh, Nguyen Dinh Bong, Do Thi Tam

Received: 16-09-2013 / Accepted: 25-09-2013
The sustainable land use management relates to the current and future areas of economics, society, culture and environment, limits land and water degradation and reduces production costs. The study aims to find out some factors which have effects on the management of agricultural land use in SonTay Town. The impact of the factors on the management of agricultural land use was analyzed by using Kruskal-Wallis test and Spearman Rank Corrrelation Coefficient in SPSS15.0 with significant level: 0.05 through the investigation of 160 households from 4 communes and 30 office workers. The results of the research show that the local people realise that there has been a remarkable change in the land use management over the period and the main factors which influence the management of agricultural land use are land policies, policies supporting capital, techniques; characteristic of land, scale of the area of farm land, and the role of media and information.
The Result of Evaluating Process Some New Hybrid Tomato Combinations at the Northern Coastal Areas of Vietnamin Autumnand Spring-Summer Season

Nguyen Hong Minh, Tran Thien Long, Nguyen Thi Minh

Received: 17-05-2013 / Accepted: 16-09-2013
A total of 22 new combinations of hybrid tomato were tested in 2011 autumn – winter (12 combinations) and 2012 Spring-Summer cropping season (10 combinations) at four locations in three provinces: Hai Phong, Thai Binh and Nam Dinh. Four hybrid combinations , T10, T12, T18 and T19 performed best in 2011 autumn – winter season and other four hybrid combinations, T12, T16, T19 and T26 showed high yield and low viral disease incidence in 2012 spring-summer season.
Study of Absorption Ability of CoFe2O4/ Bentonite Material for Methylene Blue Dye

Doan Thi Thuy Ai

Received: 22-01-2013 / Accepted: 06-05-2013
Magnetic CoFe2O4/bentonite nanocomposite was synthesized by chemical co-precipitation method. It has a large surface area of 380 m2/ g. Absorption ability of CoFe2O4/bentonite was studied on methylene blue solution. The factors that affected the absorption process, such as absorption time, temperature and pH were researched. The results showed that at 50mg/l of methylene blue solution and pH= 7-8, the absorption efficiency of CoFe2O4/bentonite for methylene blue was highest with the value of 95,0 -95,1%
Techniques ForImproving Vegetative Propagation Rate of (Polyscias fruticosa (L.) Harms

Ninh Thi Phip

Received: 01-02-2013 / Accepted: 18-04-2013
Effect of substrate, stem cutting length, cutting position and concentration of plant growth regulator on vegetative propagation and and growth of Polyscias fruticosa (L.) Harms was investigated.. The results showed that using the rooting medium mixture of 50% soil + 50% rice husk obtained the highest of shoot height, stem diameter, number of leaves/plant) and number of roots/plant). In addition, uing the main stem with 15 - 20cm length quickly dipped in for 2000 - 3000ppm α -NAA solution for 3 - 5 seconds appeared optimal for growth of Polyscias fruticosa L. stem cutting.
Selection of Thinner Pericarp Thickness for Quality of Fresh Waxy Corn

Tran Thi Thanh Ha, Nguyen Thi Hong Ngat, Nguyen Van Ha, Duong Thi Loan, Vu Thi Bich Hanh, Vu Van Liet

Received: 19-02-2013 / Accepted: 22-04-2013
Waxy corn is commonly eaten fresh in Asian countries including Vietnam. Selection for thinner pericarp is a priority for enhancing tenderness in fresh waxy corn breeding. We have evaluated 48 of local maize cultivars and inbred lines in order to identify genetic materials that have thinner perricap for the waxy maize breeding with improved quality. The 48 cultivars and inbred lines were evaluated in the field experiment with two replication in 20012 Autumn-Winter season. Kernel pericarp thickness of cultivars and inbed lines (measured by micrometer) ranged between 51,6 to 118,9 µm. Six potential lines and cultivars with desirable pericarp thinness are D27, D34, D36, D14, D22 and D35 (D27 with 51.6 µm). Using SSR markers 28 cultivars and inbred lines were detected to have QTL controlling thinner pericarp traits. Based on phenotypic evaluatione and genetic markers, six cultivars and inbred lines, D14, D22, D27, D47, D36 and D44, possessing desirable agronomic characteristics, thinner pericarp were selected for high quality waxy maize breeding programme in Vietnam.
The Impacts OfEconomic Recession On Enterprises In The North Of Vietnam

Nguyen Quoc Chinh, Nguyen Hai Nui

Received: 09-01-2013 / Accepted: 20-04-2013
Economic Recession (ER) is an essential phase of economic cycle. The 2008 - 2009 economic recession had a strong impacts on the economy in general and the business activities of enterprises in particular. The main objective of this study was to analyze the effect of ER on business activities and workers’ life of some representative enterprises in the North of Vietnam, and propose some key sulutions to minimize the negative impacts of ER and improve the adaptability of enterprises to recession conditions. The systematical and participatory approaches were used. Data collection and analysis used in this study were data synthesis, direct survey of representive companies in the North using questionaire, consultancy, and comparision methods. The study showed that enterprises have been clearly impacted by the ER in all production and business processes. The main impacts were high input prices, limited resources, difficulties in labor and loans, instability in production and consumption and decline in the enterprise performance. To minimize these negative impacts, enterprises should apply multiple solutions and at the same time with the government supports.
Effectof Stocking Density on Growth Rate and Survival of White Leg Shrimp, Litopenaeus Vannamei,Raisedon Indoor Composite Tanks

Nguyen Phuong Toan, Vu Van Sang, Nguyen Viet Vuong, Nguyen Quang Tuat, Dang Thi Diu, Doan Thi Nhinh, Tran The Muu, Vu Van In

Received: 18-02-2013 / Accepted: 20-04-2013
The effect of stocking density of white leg shrimp SPF (Litopenaeus vannamei) was carried out at different density of 40, 60 and 80 PL15/m2 for 75 days. Each treatment was replicated three times in 4m2 indoor composite tank system and feeding ratio of 10-15% body weight with CP pellets containing 38% crude protein and four times a day. During the experiment, water temperature varied between 28 and 31ºC, whereas salinity ranged from 20-24‰ in biosecurity condition. Water in the culture tanks was renewed 50% weekly. The highest growth rate in weight was found in treatment of 40 heads/m2 (1.54 g/week), followed by 60 heads/m2 (1.47 g/week) but the rate for 30 heads/m2 (1.16 g/week) was lowest. Similarly, the survival rate of shrimp stocking at 40 heads/m2 ranked highest (79.7 ± 2.6%), followed by 60 heads/m2 (78.7 ± 2,9%) and the lowest rate for the 80 heads/m2 (70,3 ± 3,3%; P<0.05). Nevertheless, there was no significant difference in the survival rate between shrimp raised at 40 heads/m2 and 60 heads/m2 (P>0,05). Size variation (CV) for 40 heads/m2 (727 ± 1.52%) and 60 heads/m2 (8.22 ± 2.5%) were considerably lower than that for 80 heads/m2 (12.9 ±2.7%; P<0.05). However, there was no considerable disparity in feed conversion rate among the three treatments (P>0,05). All shrimp sample tissues were found negative for WSSV, YHV, TSV, MBV and IHHNV.
Analyzing Causes of Failurein Contract Farming Enforcement betweenFarmer and Entrepreneur in Vietnam

Tran Quoc Nhan, Ikuo Takeuchi

Received: 08-10-2012 / Accepted: 20-12-2012
This paperreviewedresults of empirical studies of contract farmingin Vietnam and other countries. The study aimedat clarifying the conceptsof contract farming, advantagesand disadvantagesof contract farming and as well as analyzingfactors affecting contract enforcement in Vietnam. The results showedthat farm products trading under the contract between farmers and entrepreneurs in Vietnambasically has similar characteristicwith contract farming in other countries.It can be indicated that there are five models of contract farming arrangements existing in Vietnam including centralised model, nucleus estate model, multipartile model, informal model and intermediary model. Factors related to contracting context such as weakinstitutionalization of contract enforcement, market price uncertainty, low and undiversified benefits of contractand “weak market pressure”areconsidered as critical factors stronglyaffecting week enforcement ofcontract between farmers and enterprises in Vietnam.
Effect of Salinity on Reproductive Performance of SelectedBrackish Water NileTilapia Strain (Oreochromis niloticus)

Le Minh Toan, Vu Van Sang, Trinh Dinh Khuyen

Received: 27-09-2012 / Accepted: 18-12-2012
The experiment was carried out to evaluate the effects of salinity on fertility of selected brackish water Nile tilapia (Oreochromis niloticus) strain in 53 days. The experiment fish was arranged breeding in brackish water corresponding to three different salinity levels such as: 4 - 5‰, 8 - 10‰ and 14 - 16‰, the ratio of male: female tilapia was 1:2, each formula was repeated 3 times in 3 different tanks, stocking density was 4 individuals/m3 for each tank. Results show that the reproductive rate of females corresponding to 4 - 5‰ salinity was 26.2 ± 4.64%; 8 - 10‰: 17.86 ± 11.21% and 14 - 16‰: 6.88 ± 6.57%. The number of eggs per formula obtained after 7 times was obtained in 3 corresponding levels salinity was 5,229a ± 1,280 eggs, 2,721b ± 1,559 eggs and 923c ± 706 results. Relative fecundity 3 levels of salinity 4 - 5‰, 8 - 10‰ and 14 - 16‰, respectively, 4.3a ± 0.63 eggs/g fish/time was 3.36b ± 0.67 eggs/g female/times and 1.7c ± 1.27 eggs/g fish/time. Absolute fecundity of tilapia in salinity 4 - 5% was 829 ± 122.9 eggs/time delivery, salinity 8 - 10‰ of 678a ± 135,7 and at a salinity of 14 - 16‰ was 403b ± 154.5 eggs/female/delivery time. Natural frequency of females at 4 - 5‰ salinity 22.3 ± 2.23 days; 8 - 10% was 24.9 ± 3.7 days and 14 - 16‰ salinity was 25.7 ± 2.59 days. Experimental results showed that the breeding of tilapia at salinity level of 4 - 5‰ obtained the best reproduction, next to the level of salinity 8 - 10‰. Experiments show that the breeding of Nile tilapia at salinity level below 8 - 10‰ was high practical significance.
Research Results on Designing Drying System for Litchi Using Combined Thermal Convection and Radiation Method

Tran Nhu Khuyen, Pham Duc Nghia, Hoang Xuan Anh, Ngo Thi Hien, Le Huy Thuong, Truong Thi Toan

Received: 04-04-2012 / Accepted: 14-06-2012
Equipment system SV-1.0 for drying litchi by combining convection and radiation method has been designed and manufactured at Department of Agricultural products Processing and Storage, Faculty of Engineering, Hanoi University of Agriculture. This drying system has simple structure and the heat are supplied by combining thermal convection and radiation method. As a result, heat transfer effect was improved. The effect of temperature, drying air velocity, density of material in drying chamber on drying material heterogeneity of dried product and specific fuel consumption was identified. In comparison with common drying systems being used, the drying system SV-1.0 has several advantages: drying time was reduced (70.5 hours), equal to 55.7% of manual drying ovens and 94% of improved drying equipmen. The heterogeneity of dried product is 2.1%, reduced by 2.2% in comparison with manual drying oven and by 1.6% with the improved drying equipment. Specific fuel consumption is 0.45 kg of coal for 1kg of dried product, equal to 46.1% of manual drying oven and 74% of the improved drying equipment. The dried litchi product has good quality with nice shape and colour.
Some Characteristics of Semen of Ri chicken Breed Collected by Massage

Nguyen Hoai Nam, Nguyen Thi Mai Tho, Trinh Thi Phuong Thao, Nham Thuy Quynh, Le Quang Hai, Nong Van Thuong, Cao Thi My Hanh, Nguyen Thi Nhien

Received: 02-03-2012 / Accepted: 15-05-2012
This study was to evaluate some characteristics of semen of Ri chicken breed. Semen from 4 Ri cockerels was collected by massage method 3 times/week on Monday, Wednesday and Friday from August to October, 2011, and assessed under light-microscope. Motility, concentration and volume of semen were 57.91±16.79%; 2.09±0.87 tỷ spermatozoa/ml; 0.056±0.030 ml, respectively. One way repeated measures ANOVA test showed that there was no significant variation of the quality of Ri cockerels’ semen during the study period. These findings suggested that a collection frequency of 3 times/week during 2 months did not have significant effects on the quality of semen of the Ri cockerels. This is the first report about some charateristics of semen of Ri chicken beed in Vietnam. Future researches are required to evaluate other criteria of Ri cockerel’s semen and in a larger scale.

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