XÁC ĐỊNH HỆ SỐ TÍCH TỤ THỦY NGÂN CỦA MỘT SỐ LOÀI ĐỘNG VẬT THÂN MỀM HAI MẢNH VỎ Ở KHU VỰC ĐÔNG BẮC BẮC BỘ, VIỆT NAM

Some organisms (snout otterclam Lutraria rhynchaena, granular ark Anadara granosa, corrugated lucine Austriella corrugata and lyrate Asiatic hard clam Meretrix lyrata) were chosen as subjects of this research because of their high bioaccumulation, their sedentary life and their filter feeding habit. Concentration of total mercury in the water was detected at 3 positions: Lan Ha bay - Cat Ba island, Hoang Tan commune - Quang Ninh province, Dong Bai commune - Hai Phong city. Result of this research showes the different levels of accumulation in tissues of 4 species but they are lower than MOH’s allowable value (0.5 micrograms/g). The bioaccumulation factors (BAF) of corrugated lucine Austriella corrugata, Granular ark Anadara granosa, Lyrate Asiatic hard clam Meretrix lyrata and Snout Otterclam Lutraria rhynchaena were 1.344, 344, 333 and 158 respectively. These factors show that accumulation total mercury in 4 species of mollusca is in natural tendency.Nhóm động vật nhuyễn thể sống đáy (Tu hài Lutraria rhynchaena, Sò huyết Anadara granosa, Ngán Austriella corrugata và Ngao trắng Meretrix lyrata) được chọn làm đối tượng nghiên cứu do khả năng tích tụ sinh học cao, đời sống ít di chuyển, ăn lọc mùn bã hữu cơ. Đã phát hiện nồng độ thủy ngân trong môi trường nước tại 3 vị trí nghiên cứu là vị trí vịnh Lan Hạ (Cát Bà), Hoàng Tân (Quảng Yên - Quảng Ninh) và xã Đồng Bài (Cát Hải - Hải Phòng). Nghiên cứu đã xác định mức độ tích lũy trong mô thịt của 4 loài sinh vật trên ở các mức khác nhau nhưng nhưng đều thấp hơn quy chuẩn cho phép của Bộ Y tế (0,5 µg/g). Hệ số tích tụ thủy ngân BAF của 4 loài đã minh chứng được xu hướng tích lũy thủy ngân của các loài hai mảnh tại 3 khu vực nghiên cứu phù hợp với quy luật tự nhiên: hệ số BAF của Ngán Austriella corrugata là 1.344, của Sò huyết Anadara granosa là 344, của Ngao trắng Meretrix lyrata là 333 và của Tu hài Lutraria rhynchaena 158

Some Overviews on Organic Agriculture Apply Circular Economy

The paper provides an overview on agriculture apply circular economy (CE). It provides the concepts of circular economy and organic agriculture. The paper used secondary researches from topics, documents related to organic agriculture apply CE. With results which the previous studies mentioned, the paper bases on different CE theoretical approaches to clarify the concept of organic agriculture in the direction of circular economy. Keywords: organic agriculture, circular economy DOI: 10.7176/JESD/13-20-01 Publication date:October 31st 202

Factors contributing to animal health risks: Implication for smallholder pig production in Vietnam

In Vietnam, there are about four million households producing pigs of which more than half are producing at small scale, i.e., about one to two pigs per production cycle. One of the most critical constraints to pig production, especially for small scale, is the presence of animal disease. Many types of diseases have been reported by smallholder pig producers in Hung Yen such as diarrhea, pneumonia, fever, blue ear, head edema and pasteurellosis. The percentage of sick pigs is highest among piglets (27 percent), as compared with growing pigs and fatteners (five percent each). Diseases could lead to death of pigs, resulting in economic losses to the pig producers. Estimates of the cost of mortality in pig production in Hung Yen were about 3.3 million VND per household, accounting for about 13.6 percent of total income from pig production. Results of this study suggest that there are some practices that contribute to mitigating disease risk and those practices can be easily applied at small scale of pig production. These practices are related to applying a suitable production scale, isolating different age classes of pigs, designing pig houses and using specialized livestock farming tools and sanitation. The value of losses avoided from the above practices is estimated at 320.3 USD per household per year

Optimization of culture conditions of Streptomyces antibioticus strain 1083 to improve the antimicrobial activity against Aeromonas hydrophila

Fish is a healthy, high protein and low fat food that encourages the health and growth of people, especially children. However, in fact fish is very sensitive to many diseases which affects the productivity and quality of fish. Therefore, identifying the cause of the diseases and finding preventive measures become an urgent task today. In the previous study, we isolated Streptomyces antibioticus strain 1083 that has the ability to antagonize Aeromonas hydrophila - a pathogenic bacterium in fish. Based on the obtained results, we continue to perform this study to determine optimal conditions for the culture of S. antibioticus strain 1083 in order to produce antimicrobial compounds against A. hydrophila. The production of antagonists by the strain 1083 was optimized by controlling the condition of different inoculations such as media, pH, temperature and incubation period. The results indicated that International Streptomyces Project 2 (ISP2) was the best medium for S. antibioticus strain 1083 to produce the highest antimicrobial activity against A. hydrophila with 32 mm in diameter of inhibited zone. The actinomycete strain 1083 could express the maximum antimicrobial activity when they were incubated in shaker incubator (200rpm) at 40oC with pH8 in 8 days. The ability of the actinomycete strain in antagonism against A. hydrophila was evaluated by adding different culture medium volume of S. antibioticus strain 1083. With adding 10% cultured solution volume of S. antibioticus strain 1083 into the culture medium of A. hydrophila, after 1 day of inoculation the number of pathogenic bacteria cells were completely eliminated

Characterizing pig value chains in Vietnam: descriptive analysis from survey data

The traditional pig sector plays a significant role in Vietnam’s economy from production, especially for farmers in rural areas, to consumption (more than 90% of pork consumed is supplied by conventional wet markets). At the same time, the traditional pig sector is under threat from animal health and food safety risks that impact both its profitability and future viability. However, little research exists on defining key intervention points that could manage risks in a propoor, cost-effective manner. Our study highlighted and reviewed the contrast between pig value chains in two provinces (Hung Yen and Nghe An) that represent different levels of economic development in the county. Based on semi-structured questionnaires, 400 pig producing farmers and 400 pork consumers were surveyed in both provinces during July and August 2013, paying particular attention to typologies of production and consumption in rural, semi-urban, and urban zones. We also obtained information on 200 other intermediary value chain actors through semi-structured and in-depth interviews. Preliminary descriptive analysis revealed the main characteristics of various actors in the sampled value chains, including (vet and feed) input suppliers, producers, traders, slaughterhouses (or abattoirs), processors, retailers, and consumers. In particular, we found that actors in Hung Yen are more likely to be active and commercialised in pig value chains than those in Nghe An. At the same time, Nghe An is exposed to operate its chains more ‘self-sufficiently’, with ownproduced inputs, particularly feeds, and has more state-owned farms involved in breed supply. In both study sites, middlemen often perform multiple functions and are generally the most powerful actors in the surveyed chains since they have better access to information and dominate value-added activities. This may imply a potential control point for risk management in response to diseases transmitted in short-term as well as (pro-poor) profit distribution in longerterm. Moreover, the behaviours of actors in these two provinces are dissimilar in terms of production and consumption practices as a result of differences in production scale, knowledge, attitude and habits. Information from this study will provide more insightful understanding of these existing value chains and serve as the base for further economic and risk analysis