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Minh Van Nguyen  Marit Espe  Louis E. C. Conceio  Hoang Minh Le  Manuel Yúfera  Sofia A. D. Engrola  Ann‐Elise Olderbakk Jordal  Ivar Rnnestad 《Aquaculture Nutrition》2019,25(2):i-i

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Using farmers' knowledge for defining criteria for land qualities in biophysical land evaluation     

I. Messing  M. H. Hoang Fagerstrm 《Land Degradation \u0026amp; Development》2001,12(6):541-553

The objective of this paper is to present a way of complementing empirical results with farmers' perceptions in defining limiting biophysical land properties in a land suitability evaluation using the FAO framework methodology. The farmers' perceptions were identified using rapid and participatory rural appraisal (RRA/PRA) tools. The study catchment, having a semiarid continental climate and located on the Loess Plateau in northern China, covered an area of 3.5 km². Most of the land users were dependent on subsistence agriculture. There were important topographic variations in the catchment and arable cropping on steep slopes brought about degradation of land due to water erosion. The biophysical monitoring, soil survey and RRA/PRA survey, carried out one year prior to the present investigation, supplied the data needed for identification of preliminary limiting land properties and land evaluation units. The land properties that needed further investigation in the present study were slope aspect, soil workability, flooding hazard and farmers' criteria on choice of land‐use type. The farmers were able to give a comprehensive picture of the spatial and temporal variation and the importance for land‐use options of the land properties concerned, and thereby complement the information gained from empirical results (measurements). In order to guarantee good production for dry as well as wet years, both south‐ and north‐facing sites were chosen for most crops, and the slope aspect did not need to be differentiated in the final land suitability evaluation for arable crops. Grassland, however, was considered to be more suitable than woodland on south‐facing sites. Hard soil layers were found to be important, since they affected soil workability and erosion negatively, giving slightly reduced suitability for the land units in which they occurred. Flooding events affecting crops on alluvial soils negatively were considered to occur once every 5 to 10 years, which is considered to be a low rate, so this property was therefore not included in the final suitability evaluation. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

Rearing the spotted seahorse Hippocampus kuda by feeding live and frozen copepods collected from shrimp ponds          下载免费PDF全文

Tam D Thuong  Tung Hoang 《Aquaculture Research》2015,46(6):1356-1362

This study evaluated the use of live and frozen copepods collected from shrimp ponds for rearing juveniles of the spotted seahorse Hippocampus kuda. Protein and HUFA contents in frozen copepods were all higher than in Artemia nauplii, the conventional live food for seahorse juveniles. The results of this study showed that copepods can be used as feed for rearing seahorse fry and juvenile. The spotted seahorse showed obvious preference for live copepods and rarely fed on dead copepods on the tank bottom. Furthermore, the combination of frozen copepods and live Artemia nauplii resulted in highest growth and highest survival of the experimental seahorses. Further research on possible effects of DHA:EPA ratio on survival and growth of young H. kuda is recommended.  相似文献   

Doses response of dietary viscosity on digestibility and faecal characteristics of striped catfish (Pangasionodon hypophthalmus)     

L. C. Tu-Tran  Thanh‐Cong Nguyen  Johan A. J. Verreth  Johan W. Schrama 《Aquaculture Research》2020,51(2):595-604

The study analysed the dose–response relationship between dietary viscosity and nutrient digestibility, faecal waste characteristics in striped catfish and the long‐term impacts of viscosity on performance of striped catfish. This was done in two experiments: Exp.1 lasted 29 days, in which six dietary viscosity levels were created by including different amount of guar gum (GG; 0, 0.25, 0.5, 1.0, 2.0 or 3.0 g/kg) and Exp.2 lasted 60 days and assessed the long‐term effects of three dietary GG levels (0, 0.5 and 3.0 g/kg) were checked. In Exp.1, digestibility of nutrients (except crude fat) decreased linearly with dietary viscosity. With increasing viscosity, removal efficiency of faeces from the water reduced linearly, whereas the total amount of faeces produced and the fraction of big‐sized faecal particles (>2 mm). increased linearly. In Exp.1, viscosity did not affect performance. However, in Exp.2, the GG inclusion level of 3.0 g/kg (1.72 cP for the viscosity) affected fish performance. In conclusion, the best strategy for faecal waste management in striped catfish by dietary viscosity is to keep it as low as possible in the diet.  相似文献   

Salinity and temperature effects on productivity of a tropical calanoid copepod Pseudodiaptomus incisus     

Thuy T. Nguyen  Minh‐Hoang Le  Nam X. Doan  Sy T. Nguyen  Trinh S. H. Truong  Minh T. T. Vu  Khuong V. Dinh 《Aquaculture Research》2020,51(9):3768-3779

Pseudodiaptomus species are major live feeds for the early stages of economically important marine fish in hatcheries in the South China Sea. However, we know little about the combined effects of multiple environmental parameters such as salinity and temperature on copepod productivity. To address the issue, we cultured a tropical coastal copepod Pseudodiaptomus incisus in one of 24 combinations of 8 salinities (5, 10, 15, 20, 25, 30, 35 and 40 ppt) and 3 temperatures (26, 30 and 34°C). We determined development, biomass of all stages, fecundity, percentage of females with hatched eggs and 30 hr nauplii production. Overall, the biomass, fecundity and nauplii production of P. incisus were highest at the salinity of 15–20 ppt, especially at 26°C. P. incisus showed a lower performance at both lower and higher salinities. Elevated temperatures resulted in faster development, but lower biomass, fecundity and nauplii production. Especially, nauplii production was reduced by 74% at 35–40 ppt and 34°C compared to at 15–20 ppt and 26°C. Our study provides essential information for optimizing the biomass culture of P. incisus.  相似文献   

Production and economic efficiencies of intensive black tiger prawn (<Emphasis Type="Italic">Penaeus monodon</Emphasis>) culture during different cropping seasons in the Mekong delta,Vietnam     

Vu Nam Son  Nguyen Thanh Phuong  Tran Ngoc Hai  Amararatne Yakupitiyage 《Aquaculture International》2011,19(3):555-566

Production management of intensive prawn farming strongly differs between dry and wet season in terms of availability and quality of prawn seeds and water quality. Secondary data implied that prawn seed batches from the market had a total pathogen infection rate of 53%, predominantly caused by 37% white spot syndrome virus (WSSV), 19% monodon baculovirus (MBV) and 4% yellow head virus (YHV). Pathogen-free seed batches averaged to 52% during the dry season compared to the wet season (42%). Survey revealed average stocking density of 17 PL m⁻² with a survival rate of 55%, a crop yield of 2,470 kg ha⁻¹ crop⁻¹ and a net income of 6,768 USD ha⁻¹ crop⁻¹. Average production cost amounted to 3.4 USD kg⁻¹, and feed cost accounted for 58% of the production cost. Technical efficiency with respect to prawn yield and survival rate was higher during the dry season than the wet season. The probability of yield loss was 15.6 times higher in the wet than in the dry season. A positive net income can be generated for farms operating in the dry season using new ponds and performing pathogen laboratory tests on prawn seeds before stocking.  相似文献   

Spawning behaviour of Penaeus (Fenneropenaeus) merguiensis de Man and the effect of light intensity on spawning   总被引：2，自引：0，他引：2  

Tung Hoang  S Y Lee  Clive P Keenan  & Gay E Marsden 《Aquaculture Research》2002,33(5):351-357

An experiment was conducted to investigate the effect of light intensity just prior to and during spawning of Penaeus (Fenneropenaeus) merguiensis de Man in the laboratory. Neither the presence of light nor light intensity (0, 10 and 1100 lux) had a significant effect on the spawning process or hatching rate in P. merguiensis. Difference in the percentage of spawners, percentage of incomplete spawning, fecundity and hatching rate were all insignificant (P > 0.05) among the three light treatments. However, spawning was delayed (up to 21 min on average) under 1100 lux with a high percentage of incomplete spawning, compared with the Control (0 lux). For the first time, spawning behaviour of P. merguiensis was observed and fully described. The spawning process can be divided into four phases: dormant, pre‐spawning, spawning and post‐spawning by distinct behaviour of prawn broodstock. The dormant phase was characterized by a quiescent and non‐feeding period, whereas movement of prawn broodstock was active during the pre‐spawning and post‐spawning phases. Depending on the individual, spawning was completed within 3–5 min. Prawns often stayed still on the water surface during spawning with occasional manoeuvres to change the position. After a short rest at the termination of the spawning phase, prawn broodstock re‐exhibited active movement as in the pre‐spawning phase, but showing conspicuous care to the deposited eggs. The role of light in controlling ovarian development and spawning, and the behaviour of prawn broodstock in relation to maximizing fertilization rate are discussed.  相似文献   

Ferrochelatase catalyzes the formation of Zn-protoporphyrin of dry-cured ham via the conversion reaction from heme in meat     

Chau TT  Ishigaki M  Kataoka T  Taketani S 《Journal of agricultural and food chemistry》2011,59(22):12238-12245

Ferrochelatase (FECH), the enzyme at the last step of the heme-biosynthetic pathway, is involved in the formation of Zn-protoporphyrin via an iron-removal reaction of heme. To improve the efficacy of the formation of Zn-protoporphyrin from heme, the use of recombinant FECHs from porcine, yeast, and bacteria was examined. Incubation of FECH with myoglobin in the presence of ascorbic acid and cysteine resulted in the efficient conversion of myoglobin-heme to Zn-protoporphyrin. Exogenously added recombinant yeast FECH facilitates the production of Zn-protoporphyrin from myoglobin-heme and heme in meat, via the replacement of iron in the protoporphyrin ring by zinc ions. A large amount of Zn-protoporphyrin was also generated by the catalysis of FECH using an intact piece of meat as a substrate. These findings can open up possible approaches for the generation of a nontoxic bright pigment, Zn-protoporphyrin, to shorten the incubation time required to produce dry-cured ham.  相似文献   

Levels and Chemical Forms of Heavy Metals in Soils from Red River Delta, Vietnam     

Nguyen Minh Phuong  Yumei Kang  Katsutoshi Sakurai  Kōzō Iwasaki  Chu Ngoc Kien  Nguyen Van Noi  Le Thanh Son 《Water, air, and soil pollution》2010,207(1-4):319-332

Levels and chemical forms of heavy metals in forest, paddy, and upland field soils from the Red River Delta, Vietnam were examined. Forest soils contained high Cr and Cu levels that were higher in subsurface than in surface layers. Levels of Cu, Pb, and Zn that exceeded the limits allowed for Vietnamese agricultural soils were found in the surface layer of a paddy field near the wastewater channel of a copper casting village. High amounts of Zn accumulated in the surface soil of paddy fields close to a fertilizer factory and an industrial zone. In these cases, larger proportions of Cu, Pb, and Zn were found in the exchangeable and acid-soluble fractions compared to the low-metal soils. We conclude that no serious, large-scale heavy metal pollution exists in the Red River Delta. However, there are point pollutions caused by industrial activities and natural sources.  相似文献   

基因工程菌枯草芽孢杆菌GEB3产生的脂肽类抗生素及其生物活性研究   总被引：10，自引：1，他引：10  

高学文  姚仕义  Huong Pham  Joachim Vater  王金生 《中国农业科学》2003,36(12):1496-1501

 利用MALDI TOF MS技术 ,鉴定了将lpaB3基因转入枯草芽孢杆菌Bacillussubtilis 168菌株所构建的工程菌GEB3产生的脂肽类抗生素种类。结果表明 ,GEB3仅产生表面活性素 (surfactin) 1种脂肽类抗生素。经LC MS分析 ,GEB3产生由 13、14和 15个碳原子的脂肪酸链构成的标准表面活性素变异体 (standardsurfactinisoforms)。生物活性检测表明 ,该工程菌产生的脂肽类抗生素表面活性素具有抑制小麦纹枯病菌和稻瘟病菌菌丝生长的作用  相似文献