Browsing by Subject "Aquakultur"

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    A case study: Fish production in the integrated farming system of the Black Thai in Yen Chau district (Son La province) in mountainous North-western Vietnam - current state and potential
    (2009) Steinbronn, Silke; Becker, Klaus
    Son La province is located in mountainous north-western Vietnam and belongs to the poorest regions of the country. In the valleys of this province, fish farming is one of the major activities among farmers who belong to the ethnic Black Thai minority. Up until now, the aquaculture system practiced here has not been scientifically investigated. There is generally very little data available regarding the aquaculture of resource-poor farmers in Southeast Asia. This lack of information can be partly explained by the difficulty in obtaining this data. However, a solid understanding of current aquaculture systems is necessary for any kind of future involvement. Within the course of a special research program (SFB 564), aquaculture practices in three communes of Yen Chau district (Son La province) were surveyed between 2004 and 2006. The research was conducted in a holistic way in order to obtain a detailed description of the typical local aquaculture system with its potentials and limitations. In addition, measures for improvement were developed, which will be tested during the next phase of the special research program. The data was collected and analyzed on three different levels. On the ?macro level?, general data is presented regarding the land use and irrigation system in the studied area. Data on the ?meso level? concerns the aquaculture and agriculture system and was predominantly collected through interviews with 155 farmers, 22 village headmen and other stakeholders. On the ?micro level?, an in-depth investigation based on measurements and close observation of 6 individually selected case study farms is presented. This data includes the limnological pond conditions, fish growth rates, food conversion and the profitability of the aquaculture system. The data gathered during these investigations compensates for the information that could not be satisfactorily gathered through the interviews alone. Currently, around 63% of the households in the study area produce fish in ponds. The aquaculture production is closely linked with other farming activities and is integrated into the overall irrigation system. Farmers stock different carp and tilapia in polyculture with the main species being grass carp. Fish are mainly fed leaves and by-products of crop production, weeds and manure, e.g. from buffalo. The pond system is feed-based and exhibits a more or less continuous water flow; both of these features are rather atypical for small-scale aquaculture. In the case study farms, the average fish stocking density was 1.0 fish m-2. Calculated based on one hectare, the average daily feed application was 37.1 kg dry matter (DM) and the annual net production of aquatic species 1.5 tons ha-1, of which roughly 2/3 were sold. The average conversion of feed (DM) to aquatic species biomass was 7.7:1, and the conversion of added nitrogen (feed and manure) to produced nitrogen (aquatic species) was 14.7%. The yields in the presented system are relatively low compared to other feed-based aquaculture systems. Nevertheless, it has been shown that aquaculture production contributes significantly to food security, generates income and plays a significant role in farmers? lives. At present, the local market in Yen Chau cannot be completely satisfied by the districts? fish production alone. Recently, a road was upgraded that connects the north-western mountains with the country?s capital Hanoi. As a result, fish from the more intensive aquaculture in the lowlands has started to flood the local markets. This development is expected to proceed, which will leave farmers unable to compete in the market in the future. In order to produce fish in a sustainable way, the current system must be improved so that the local fish production increases. There are various reasons that can explain the relatively low productivity in the ponds. These include an unclassifiable grass carp disease that leads to high mortalities, poor water quality, low fish growth rates caused by low quality of fish seed, low quality of feed and manure applied as well as low natural food availability in the ponds. Furthermore, farmers seem to have limited knowledge regarding basic aquaculture techniques, which may be explained by the lack of training or extension services available in this field. In the present study, a ?basket? of modification measures have been proposed. These measures concern the farms themselves (e.g. improved pond management), the institutional and political framework (e.g. support of the local hatcheries) as well as the research. The focus of the next part of the special research program will be the identification of the causative agent of the grass carp disease and the development of prevention and treatment strategies. Additionally, a modified watering and feeding management system will be tested scientifically. It is expected that this locally adapted, improved pond system will lead to significantly higher fish production.
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    An economic analysis of fish demand and livelihood outcomes of small-scale aquaculture in Myanmar
    (2021) Aung, Yee Mon; Zeller, Manfred
    Given that capture fishery production has either remained stagnant or declined globally, aquaculture has been responsible for the massive growth in the supply of fish to fulfill increasing demand and has also improved livelihoods. The development of the fishery sector, particularly aquaculture, has the potential to contribute to the Sustainable Development Goals (SDGs). New technologies and effective fishery management policies play critical roles in achieving this sectors contribution to the SDGs. Although aquaculture in Myanmar is dominated by large-scale fish farming, a larger number of small-scale aquaculture (SSA) households exist either legally or illegally because profitability and employment opportunities have enticed them to enter the sector. However, the potential of SSA farmers and their challenges are still overlooked. Even though Myanmar is one of the major consumers of fish and producers of aquaculture fish worldwide, to date, a holistic approach that considers the demand and supply side of Myanmars aquaculture sector is rare. The thesis focuses on two main topics. One topic is an analysis of the disaggregated fish demand system. Empirical evidence on whether the aquaculture sector can meet household demand through adequate availability of and accessibility to fish is vital to ensure household food and nutrition security and understand the future of the fish demand. The second main topic focuses on the two aspects of production based on SSA farms; production efficiency and impacts on welfare outcomes from the adoption of sustainable aquaculture (SA) technologies. To fulfill fish demand by increasing the supply of fish from farms, production efficiency of the farmers needs to improve to generate profitable in the face of lower fish prices that will accompany an increase in supply. In addition, traditional aquaculture production practices are risky and are not a long-term option for SSA farmers. Therefore, renewing or modifying productive resources and implementing new technologies may play critical roles in the development of a sustainable SSA sector. The study on the fish demand analysis in Chapter 2 relies on nationally representative data from the "Myanmar Poverty and Living Conditions survey (MPLCS) in 2015,". For the production side analysis in Chapters 3 and 4, primary survey data originate from 440 SSA households collected in three townships in Phyapon District, Ayeyarwady Delta region, Myanmar. Chapter 2 estimates the demand parameters differentiated by fish supply sources (aquaculture, freshwater capture, marine capture, and dried fish) and household groups (wealth group and household location) in Myanmar using a three-stage budgeting framework, combined with a Quadratic Almost Ideal Demand System (QUAIDS). The results reveal that fish demand from all sources of fish and household groups increases with income because fish is the second most crucial food commodity after rice in Myanmar. A substantial share of the increasing demand for all sources of fish is likely to come from poor and rural households with growing incomes due to their higher-income elasticity for all sources of fish. Moreover, less elastic price elasticity of demand in most cases for poor and rural households indicates that those households have less animal protein substitutes for fish available and accessible because fish is the cheapest form of an animal protein source in Myanmar. Due to the income responsiveness of aquaculture fish, its demand will grow faster than that of other fish sources. This study confirms that the rapidly growing aquaculture sector can compensate for the concurrent stagnation of capture fisheries production to fulfill the increase in the fish demand. The studys findings suggest that effective management policies and new technologies are essential to sustain the fish supply from capture fisheries and aquaculture. Intervention programs that sustainably increase aquaculture production will generate the most effective and significant effects on securing households food and nutrition security in the long-run. Chapter 3 analyzes the current technical efficiency level of SSA farms and the link between womens level of participation in decision-making (WPDM) activities and the technical efficiency of fish farming using the two-stage double bootstrap data envelopment analysis (DEA) method. The results show that most SSA farming households are not technically efficient, performing in a range of 45%-60% below the production frontier. All the inputs used contain slacks, such that all of them are over-utilized in inappropriate ratios. This study reveals that while some of the households socio-economic and production characteristics are significant shifters to enhance efficiency of fish farming, decision-making power of women at the household-level is found to significantly improve the level of technical efficiency through its effects on the ability of household members to allocate and organize resources optimally. This study highlights the vital need to promote intervention programs targeted at improving the technical efficiency of SSA farming households. Policies and intervention programs aimed at increasing productivity in the aquaculture sector would benefit by including women empowerment programs to reduce gender inequality and promote equity. Chapter 4 evaluates the determinants and the impacts of SA technologies adoption on SSA households’ welfare outcomes using the endogenous switching regression (ESR) model. The significant value of the correlation coefficients between the error terms of the adoption decision and the outcome equations, as well as heterogeneity in the outcome variables between adopters and non-adopters, confirm that the ESR model is more appropriate than data pooling in a regression model. The models actual and counterfactual results highlight that the adoption of SA technologies increases the SSA households welfare outcomes, measured by fish yield per ha, Household Dietary Diversity Score (HDDS), and Total Food Consumption Score (TFCS). However, the actual adopters would benefit the most in terms of fish yield per ha and TFCS from adopting SA technologies because the average treatment effects of adoption on adopters are larger than that of non-adopters for these variables. The results highlight that household knowledge about aquaculture production and information sources are main drivers for the adoption decision and improving welfare outcomes. Therefore, appropriate policies targeting SSA development should emphasize the promotion of farmers awareness and adoption of SA technologies by providing improved extension services. This thesis findings contribute to the current debate that the development of the aquaculture sector can help achieve some of the SDGs. In particular, aquaculture can help end hunger through increased food security by making fish more widely available and accessible by increasing the supply of fish. Moreover, aquaculture can improve gender equality and women’s empowerment through creating employment opportunities linked to the aquaculture sector. Given the lower technical efficiency level and positive welfare impacts of SA technologies, it is recommended that the government and other development organizations disseminate information on the improved aquaculture practices and suitable input use through improved extension services to SSA farmers. Due to the dominance of a single fish species in the aquaculture sector, the government needs to support research and development programs in the hatchery sector for a new generation of species. Another recommendation is to reformulate the current "Farmland Law 2012" because it puts restrictions on converting agricultural land to fish ponds, which is preventing farmers entering the aquaculture sector legally. The above policy recommendations are crucial to achieve growth in the SSA sector and increase women’s intra-household decision-making power, thereby opening the door to improve livelihoods.
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    Development of supplemental diets for carp in Vietnamese upland ponds based on locally available resources
    (2010) Nguyen Ngoc, Tuan; Focken, Ulfert
    Cyprinids play very important role in aquaculture, especially in Asia and Pacific regions. Vietnam is not an exception. Although aquaculture in Vietnam increased dramatically recently, its high value products such as catfish, tiger prawn seem to be unaffordable for the people in rural areas, especially for the mountainous ethnic minority in the North who are more independent to herbivorous and omnivorous fish such as grass carp, Indians carp, and common carp. Yen Chau is a district of Cyprinids play very important role in aquaculture, especially in Asia and Pacific regions. Vietnam is not an exception. Although aquaculture in Vietnam increased dramatically recently, its high value products such as catfish, tiger prawn seem to be unaffordable for the people in rural areas, especially for the Son La province, located in mountainous region in North-Western Vietnam. In this district, Black Thai ethnic minority accounts for approximately 54% population. Besides producing huge amount of grain and tuber crop such as maize and cassava for selling, aquaculture in a small poly-culture pond system is also a very typical activity which supplies an important nutritional source for human consumption and income generation as well. However, even though most of farmers in Yen Chau own at least one pond each, the demand on the local market cannot be covered (Steinbronn, 2009). Recently, unknown diseases causing high mortalities could be the reason of the decrease of grass carp production. To avoid risk from losing grass carp, farmers are tending to change the composition of the fish species stocked in favour of e.g. common carp and mud carp without having an appropriate feed base for these species. So far, no high quality feed was applied into the pond system. Therefore, the study entitled ?Development of supplemental diets for carp in Vietnamese upland ponds based on locally available resources? was conducted to not only contribute to an improvement of income and food security in the region but also meet the appeal of improvement of scientific knowledge on cyprinids which is inadequate with their great contribution. In the study, most of the possible feed ingredients were collected and analyzed for nutritive and non-nutritive values. Based on the results of the analysis a number of diets were formulated for 30% of CP and 10% of CL then tested by common carp. In total, four experiments were designed. The first was conducted in laboratory in which common carp were fed by local pelleted feed with 25, 50, and 75% protein derived from local ingredients. Results of this trial were confirmed by the trial 2 which was implemented under pond condition at Hanoi University of Agriculture. Trial 3 was conducted to compare different protein (full fat soybean meal and soybean cake) and carbohydrate sources (maize and cassava powder). Furthermore, sweet potato leaves were preliminarily investigated in fish feed inclusion. The last trial, trial 4, was carried out to evaluate the use of earthworm for common carp. Trial 1, 3 and 4 were designed for a recirculation system in which five common carp were stocked in each aquarium of 40 l with 3 replicates. Water flow through the aquaria was maintained at 6-7 litters per minute. Water temperature, DO and pH were kept at 25-27°C, above 4 mg/l and around 7.0-8.0, respectively. The photoperiod was set up at 12 hrs light:12 hrs dark. Fish were fed daily five times metabolic body mass requirement for eight weeks. The trial 2 consisted of four feeding groups (3 test diets and 1 control), each having three replicates. In each net, 45 common carp were stocked, Fish were fed three times per day (8h, 12h, and 16h) at a feeding rate of 5 times of maintenance requirement manually. Feed amount was adjusted every ten days after taking the weight of fish. The total trial lasted for 2 months. Analytical results show that all of local materials have good nutritive values, similar or better that those in other regions. Besides, fish meal and many other ingredients can be used as source of protein such as full fat soybean meal, soybean cake, meat meal, as well as earthworm powder. This earthworms Perionyx excavatus show a suitable quality for fish feed, high protein (71% of DM) and amino acids in comparison with many conventional protein sources, including fish meal. Replacement of 70% of protein (~ 20% of DM) by earthworms can significantly improve growth of fish. However, it is still unclear in full replacement fish meal by this material. Using maize and cassava in Yen Chau is also feasible because these materials not only are cheap but also are the most available. Among all plant materials, full fat soybean seems to be the best ingredient with high protein and lipid content. In contrast, fish seem to be deficient of nutrient by feeding sweet potato leaf inclusion diets. In conclusion, except for sweet potato, all of local ingredients can be used for fish feed formulation. The local feeds were well digested, utilized by omnivorous common carp. Despite local feed ingredients did not give the best growth of fish, they gave the best results in term of economic return. Local ingredient feed gave the lowest cost of feed as well as the lowest cost of fresh fish produced. The field trial fish performance seems to be better than in the laboratory due to receiving certain amount of natural food. Thus, fish utilize feed more efficiently resulted in reduction of feed conversion ratio as well as cost of feed per unit of fish produced. Transfer knowledge about low-cost feed to the local farmer together with basal techniques of producing, storing, and effective using fish feed is an important issue which could help farmers to improve production of fish in the region as well as contribute to poverty alleviation in the rural areas in Vietnam.
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    Effects of low dietary levels of saponins on two common culture fish - common carp (Cyprinus carpio L.) and Nile tilapia (Oreochromis niloticus (L.))
    (2001) Francis, George; Becker, Klaus
    Saponins are a group of compounds present in many wild plants and cultivated crops and are commonly found in traditional medicinal preparations. Feeding experiments using saponin-supplemented (commercial Quillaja saponin) feeds were conducted in two commonly cultured fish species, namely common carp (Cyprinus carpio L.) and tilapia (Oreochromis niloticus (L.)). Quillaja saponins (QS) at dietary levels of 150 mg kg-1 and 300 mg kg-1 significantly increased body weight gain in common carp and Nile tilapia compared to controls. When fed to tilapia fry QS (700 mg kg-1) altered the normal 1:1 sex ratio. In separate, in vitro measurements it was found that QS stimulated the release of leutinising hormone (LH) from cultured tilapia pituitary cells, but apparently this did not happen in vivo since serum levels of LH were not found to be elevated in the saponin fed fish. Dietary saponins were also found to affect serum and muscle cholesterol levels. Adult tilapia - but not tilapia fry - fed a dietary level of 300 mg kg-1 QS were found to have significantly higher muscle cholesterol levels than fish fed the control diet. In tilapia fry, the average serum cholesterol levels in males showed a steady increase from dietary QS levels of 0 to 700 mg kg-1, while no such trend existed among the females. Supplementation with 50 and 100 mg kg-1 of Yucca schidigera butanol extract (containing steroidal saponins) did not significantly promote the growth of carp despite showing initial promise. The purified haemolytic fraction of triterpenoid Gypsophila saponin extract (isolated using column chromatography) did not produce any toxic effects in carp at dietary levels up to 250 mg kg-1 in a preliminary feeding trial. A growth promoting effect was however evident at the very low level of about 5 mg kg-1 when the purified fraction was used. More research needs to be done to determine the mechanisms of action of QS and to test whether saponins from other sources have similar effects.
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    Evaluation of suitability of non-toxic and detoxified Jatropha curcas L. meal as feed for fingerling common carp, Cyprinus carpio L., with reference to phytase application
    (2012) Richter, Nahid; Becker, Klaus
    Jatropha curcas L. is a hardy plant which can thrive on marginal degraded lands. Jatropha seeds contain about 300-350g kg-1 oil, which is used as fuel or in transesterified form as a substitute for diesel; they also have considerable protein quality. However, Jatropha contains antinutrients such as lectins, trypsin inhibitors and phytic acids at high levels and in toxic varities phorbolesters cause detrimental effect. Common carp fed heat-treated non-toxic Jatropha meal (JM) has been shown to have higher weight gain and protein efficiency ratio than those fish fed untreated JM. However, these parameters were significantly lower in the aforementioned trial when compared to fish fed a fish meal (FM) based diet. Reduced growth performance in fish fed non-toxic JM might be attributable to the deficiency of some essential amino acids such as lysine, to high levels of phytic acids or the presence of antinutrients. These may indicate the need for additional processing of JM for common carp. This work was therefore conducted to test various ways of further improving the nutritional quality of JM to increase the levels of inclusion in diets for common carp. In the first experiment, four diets based on 50% replacement of FM with defatted non-toxic JM were formulated, one with no further JM treatment, the second with 80% aqueous ethanol extraction before diet formulation, the third supplemented with 1% L-lysine and the fourth with 500 FTU phytase (5000G, Natuphos). These were compared to a standard, FM based diet. The results showed that diets with 500 FTU/kg phytase or 1% L-lysine could maintain common carp?s growth performance at a level comparable to fish fed a FM diet. Fish fed diets containing JM and ethanol treated JM had significantly lower growth performance than the control. The addition of 1% L-lysine or 500 FTU phytase enhanced percent body weight gain, food conversion efficiency and specific growth rate to a level comparable to those of the control. Furthermore, the addition of 500 FTU phytase significantly increased whole body Mg, P and K to the levels of those fish fed Diet Control. When the level of JM replacement was increased from 50% to 75% while at the same time supplementing the diets with inorganic phosphorus (Experiment 2), however, a significant decrease in body weight gain of common carp was observed both with and without 500 FTU phytase. In a third experiment, the effect of JM diets with added phytase but without phosphorous supplementation was therefore investigated in more detail. At the end of the eight week trial, phytase supplementation had not affected body mass gain (BMG), food conversion ratio (FCR) and specific growth rate (SGR) of fish. However, whole body phosphorous (P), P gain and P retention were significantly improved in fish fed JM with phytase supplementation when this was compared to the fish fed JM without phytase. Moreover, fish fed JM diets indicated higher O2 consumption per gramme body mass gain than carp fed FM diets. Energy expenditure per gramme protein retained was significantly higher for fish fed JM with or without phytase addition, indicating that the utilisation of JM was associated with higher energy costs for the fish. In the final experiment, the nutritional quality of non-toxic JM was compared to that of the toxic variety once appropriate measures had been taken to detoxify the latter. FM was replaced with either of the two at 75% of total dietary protein, for each Jatropha variety once without further supplementation and once supplemented with 500 FTU phytase and 1% lysine. The results of this experiment indicated that there was no significant differences in final body mass (FBM), % BMG, feed intake (FI), FCR and specific growth rate (SGR) of fish fed diets Control and non-toxic, supplemented JM. However, fish fed diets based on detoxified or non-toxic, unsupplemented Jatropha showed significantly inferior growth parameters when compared to carp fed the first two diets (p<0.05). Whole body P was significantly higher in fish fed the Control and non-toxic JM diets (with/without phytase and lysine) than fish fed either of the two detoxified JM diets (p<0.05). The depressed growth performance in the group fed detoxified JM could imply that the detoxification process was not complete and traces of phorbolesters may still be present in the diets. This work has shown that, given proper treatment, JM can act as a suitable replacement for FM at high levels in diets for common carp. The results of this work suggest that phytase addition to enhance phosphorous availability and lysine supplementation to correct the essential amino acid imbalance are two factors that have significant effects in improving JM suitability for common carp.
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    Jatropha meal and protein isolate as a protein source in aquafeed
    (2011) Kumar, Vikas; Becker, Klaus
    As aquaculture continues to develop, there will be an increasing need to use alternative plant proteins in aquaculture diets so that aqua eco-systems will be sustainable. Jatropha (DJKM, H-JPKM and DJPI) can be used as protein rich sources in the diets of fish and shrimp. There is a high potential for the safe use of DJKM, H-JPKM and DJPI in diets for fish and shrimp without compromising performance, provided that these ingredients are free of toxic factors. The detoxification process developed in Hohenheim is simple and robust and produces products that are safe and of good quality. Their addition to fish and shrimp diets gave excellent performance responses without any ill effects on animal health or safety. Effects on growth and nutrient utilization: ? Detoxified Jatropha kernel meal, H-JPKM and DJPI could replace 50%, 62.5% and 75% fish meal protein respectively without compromising growth performance and nutrient utilization in fish. In addition, DJKM could also replace 50% fish meal protein with no adverse effects on growth and nutrient utilization in shrimp. If the replacement levels are exceeded, the producer must examine the nutrient profile of the feeds carefully to ensure that desired production levels can be achieved and fish and shrimp health maintained. ? High inclusion (>50% fish meal protein replacement) of DJKM decreased the efficiency of conversion of feed to body mass. This could be explained partly by the increased mean feed intake which was possibly a reaction to the reduced protein retention, measured as protein efficiency ratio and protein productive value. No such effects were seen with the use of DJPI in common carp diets. ? Increased DJKM inclusion in diets caused a significant lowering of protein, lipid and energy digestibilities. No such effects were seen when DJPI was used in common carp diets. Effects on energy budget: ? Feeding DJKM and H-JPKM to common carp and Nile tilapia respectively did not change the major components of the energy budget (routine metabolic rate, heat released and metabolisable energy) compared to fish meal and soybean meal fed groups. These results revealed that dietary protein sources DJKM and H-JPKM can be efficiently utilized for growth by common carp and Nile tilapia respectively, as well as soybean meal and fish meal. Effects on expression of growth hormone and insulin-like growth factor-1 encoding genes ? As the level of DJKM inclusion increased in the common carp diet, growth rate decreased. The expression of Insulin-like growth factor-1 (IGF-1) in liver also decreased with increase of DJKM in the diet and that of the growth hormone in liver decreased. Effects on clinical health parameters and gut health: ? No mortality and unaffected haematological values suggested the fish were all in normal health. Alkaline phosphatase and ALT activities; urea nitrogen, bilirubin and creatinine concentration in blood were in the normal ranges which showed that there was no liver or kidney dysfunction. ? The measured plasma nutrient levels gave no indications of stress, but increasing the level of plant protein in the diet decreased plasma cholesterol. This may be related to high NSP content or reduced dietary intake of cholesterol. Decrease in muscle cholesterol level is also expected which could be considered good for human health. ? Histopathological evaluation of organs showed no damage to the stomach, intestine or liver of common carp or rainbow trout. Effects of Jatropha-phytate in Nile tilapia The defatted Jatropha kernel meal obtained after oil extraction is rich in protein (58−66%) and phytate (9 −11%). The phytate rich fraction was isolated from defatted kernel meal using organic solvents (acetone and carbon tetrachloride). It had 66% phytate and 22% crude protein and its inclusion in fish diets showed the following: ? Negative effects on growth performance, nutrient utilization and digestive physiology (nutrient digestibility and digestive enzymes). ? Adverse influences on biochemical entities such as metabolic enzymes (alkaline phosphatase and alanine transaminase) and electrolytes/metabolites. Salient changes include decreased red blood cell count and hematocrit content, decreased cholesterol and triglyceride concentrations in plasma and decreased blood glucose levels. The adverse effects observed may be due to the interaction of phytate with minerals and enzymes in the gastro intestinal tract, resulting in poor bioavailability of minerals and lower nutrient digestibility. The level of phytate used in the present study (1.5 and 3.0%) corresponds to 16.5% and 33.0% of DJKM in the fish diet. The DJKM at levels > 16.5% in the diet would exhibit adverse effects in Nile tilapia. Addition of phytase to the phytate containing diets would mitigate the adverse effects of at least up to 3% Jatropha phytate (or 33% DJKM) in the diet. Addition of phytase (1500 FTU/kg) in diets containing DJKM is recommended to maximize their utilization by Nile tilapia.
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    Nutrient flow in improved upland aquaculture systems in Yen Chau, province Son La (Vietnam)
    (2014) Pucher, Johannes Gregor; Focken, Ulfert
    In South-East Asia, pond aquaculture plays an important role in the integrated agriculture aquaculture systems of small-scale farmers and contributes to their food security and income. In mountainous regions, aquaculture differs from aquaculture that is practiced in the lowland due to differences in climate and availability of feeds, fertilizers and water. In Northern Vietnam, the traditional aquaculture is a polyculture of 5-7 fish species. The macro-herbivorous grass carp (Ctenopharyngodon idella) is stocked as the main species. Common carp (Cyprinus carpio), silver carp (Hypophthalmichthys molitrix), bighead carp (Aristichthys nobilis), mrigal (Cirrhinus mrigala), mud carp (Cirrhinus molitorella) and Nile Tilapia (Oreochromis niloticus) are stocked as secondary species and are often insufficiently nourished by farm by-products. Manure is used by farmers as fertilizer for natural food resources. Ponds are managed as a constant water flow-through system. The inflowing water introduces soil particles eroded from the sloping fields of intensively cultured maize and cassava into the ponds, and cause high turbidity that limits both the primary and secondary production. The fish production of this system is low at about 1.5 ± 0.3 t ha-1 a-1 and is mainly limited by the poor quality of pond inputs, low availability of natural food resources, low oxygen production in the ponds and the occurrence of a species-specific disease that causes high mortality in grass carp. To improve the local fish production of small-scale farmers, changes in the traditional pond management were designed and tested in farmers’ ponds in the uplands of Northern Vietnam. These changes included the reduction of water flow through the ponds to reduce the introduction of eroded particles and reduce the turbidity. Chemical fertilizers were added to increase the productivity of natural food resources and encourage higher primary production. The disease-prone grass carp was replaced as the main species by common carp that command a similarly high price on the local markets. To feed the omnivorous common carp, supplemental pellet feeds based mainly on locally available resources were applied to the ponds. In a pond trial, the traditional and modified pond managements were compared for water quality parameters, availability of natural food resources, fish yields, nutrient utilisation efficiencies and monetary net benefit. In a 15N tracer experiment, the nitrogen dynamics in the natural food web in local ponds were compared under the two types of pond management. Acceptability of the modifications by local farmers was evaluated. In a net cage trial, the suitability of earthworm meal as a replacement for fishmeal in supplemental pellet feeds for common carp was tested. In another net cage trial, the effect of pesticide contaminated grass feeds on the feed intake and health condition of grass carp were tested. When compared with traditional pond management, the modified pond management was found to result in reduced water turbidity, deeper phototrophic zones, higher availability of natural food resources, higher primary production and higher fish yield. In addition, the small plankton benefited from the changes and allowed significantly higher growth rates of filter feeding fish. Common carp and grass carp had higher yields due to the changes. Under both types of pond management, nitrogen compounds were assimilated rapidly into the natural food web and there were high rates of sedimentation and re-mobilization of settled nitrogen from the pond bottom. Generally, the modifications to pond management were associated with increased nutrient utilisation efficiencies and resulted in higher net benefits and more stable pond culture conditions. It was shown that plant material from pesticide-treated fields should only be used cautiously as feeds for grass carp because pesticide residues reduce feed intake and adversely affect fish health. Low cost modifications were well accepted by the farmers. Application of supplemental feeds and chemical fertilisers, which required a continual monetary investment, were less well received. The better-educated farmers are more likely to further invest in aquaculture and might act as local adopters. To reduce the costs of feeds for common carp, earthworm has been shown to be suitable as a replacement for fishmeal in feeds. Vermiculture might therefore be a suitable additional farming activity in combination with the implementation of pond management modifications. Formation of fish farmer cooperatives might further increase the acceptability of innovations. The improvements to pond aquaculture that have been developed here may have a beneficial impact on fish production, food security and income of small-scale farmers in the uplands in South-East Asia if the information is suitably transferred through education programmes that train farmers in technologies that have been specially adapted to conditions in the uplands.
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    Quantifying pond and labor productivity of small-holder aquaculture farmers in the central dry-zone of Myanmar
    (2019) Chertkov, Georgi
    To date, aquaculture in developing countries is still largely based on unimproved fish species. As a result, indigenous fish species often show poor growth rate, high fish mortality, and may have high labor production costs. By introducing Genetic Improvement of Farmed Tilapia (GIFT) in Myanmar, WorldFish aims to increase pond and labor productivity such that smallholder farmers earn more from aquaculture from their scarce land, capital and labor resources. The case study presented below purposely selected fish farmers for a micro-economic and partially technical study on labor and pond productivity in aquaculture. Quantitative and qualitative research methods were used to obtain very detailed data allowing me to estimate pond and labor productivity under existing smallholder farmers conditions in Myanmar. The research region was the Central Dry Zone of Myanmar, an area close to those hatcheries which have been identified by World Fish and national research partners. The case study assesses the current productivity and income from pond aquaculture derived by smallholders and provides crucial baseline information for the planned study during 2020/21 to assess the food security, productivity, and income effects of introducing improved tilapia to these smallholder farmers. Information collected during the study regarding problems faced by smallholder aquaculture farmers in the Central Dry Zone will be useful to ensure better delivery of future projects and objectives. Investment scenarios included in the case study aim to provide a demonstration of how future changes to the practices of smallholder aquaculture farmers could impact their profitability. A more productive smallholder aquaculture sector in Myanmar could help to reduce the availability and prices for fish which is a major source of protein and micronutrients for the people of Myanmar.
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    Socio-economic analysis of aquaculture groups in Hta Naung Wun Village and Shwe Baw Kyun Village in Shwebo Township, Myanmar
    (2019) Casagua Diaz, Lizeth Tatiana
    Myanmar is one of the largest fish producers in the world. In 2016, the country ranked eighth among the largest global inland aquaculture producers. Ninety percent of inland aquaculture in Myanmar is geographically concentrated in the Ayeyarwady Delta region, in lower Myanmar. Previous studies have indicated that aquaculture in Myanmar has the potential to grow with the improvement in production conditions, access to credit and post-harvest technologies. Given the promising conditions, intervention projects to develop aquaculture in the country such as Myanmar Sustainable Aquaculture Programme (MYSAP) are currently implemented. The Myanmar Sustainable Aquaculture Programme (MYSAP) is funded by the European Union (EU) and the German Federal Ministry for Economic Cooperation and Development (BMZ) and is implemented by Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH and the Department of Fisheries. WorldFish Myanmar is realising MYSAP’s inland component under a GIZ grant agreement, with Ar Yone Oo, BRAC Myanmar and Malteser International as sub-contracted implementing partners. In order to reduce the deficit of information about aquaculture in regions different to the national cluster, the current study provides a general view of the current market dynamics faced by fish farmers in Shwebo township, Sagaing Region, as a contribution for the knowledge about aquaculture in Myanmar in regions where it has not been widely documented. To do so, this study implemented a qualitative explorative approach using content analysis based on grounded theory for the culture season 2018-2019. A total of 26 fish farmers and 5 key informants were interviewed in Hta Naung Wun and Shwe Baw Kyun villages, using structured questionnaires. Regarding the proportion of the fish harvested used for family consumption, this study found a difference of 5.2 percentual point on the quantity of fish used between the two villages. This study identified that processing companies bought 94.32% of the total fish traded in the study area during the last culture season. The main characteristic influencing the purchases made by the processor is the fish size, with a preference for fish at market size. This study found a gap between fish supply and demand, showing that 80% of the fish supplied do not correspond with the attributes demanded. Fish farmers reported production challenges that potentially limit the aim to produce fish at market size. The challenges reported in the surveys show limitations in access to fish feed and water supply. Exploring farmer-based perceptions regarding the importance of the role of MYSAP programme to the access, this study found that fish farmers gave the highest importance scores to the access to fingerlings and training, and the lowest scores to the access to fish feed and buyers. This study suggests encouraging collective actions among fish farmers in order to implement bulk purchasing, share used of equipment, improve the flow of information and coordinate harvest times, which might benefit fish farmers in the study area. In addition, to overcome the current challenges is important to coordinate with the local government.