Báo cáo nghiên cứu nông nghiệp " Improving traditional integrated farming systems (VAC) - a new livelihood option for poor farmers in the coastal communities " pptx

Collaboration for Agricul ture and Rural Development (CARD) Program 306 DEMONSTRATION OF SNAKEHEAD FISH IN TANKS AS A NEW MODEL OF THE TRADITIONAL VAC SYSTEM TO REDUCE ORGANIC POLLUTION AND IMPROVE INCOME FOR FARMERS IN THE CENTRAL COASTAL VIE TNAM Project title: Improving traditional integrated farming systems (VAC) - a new livelihood option for poor farmers in the coastal communities Project c ode : CARD 027/07 VIE Author(s): Võ V ăn B ình 1 , Đào Văn Phú 1 , Nguy ễ n Quang Chương 1 , Mai Văn Tài 1 , Ass oc. Prof . Ravi Fotedar 2 , Jane Fewtrell 2 Project Implementing organisations: 1 Centre for Environment and Disease Monitoring in Aquaculture (CEDMA) – RIA1 2 Agriculture and Environment - Division of Science and Engineering - Curtin University of Technology , Australia SUMMARY In order to overcome the limitation of land available for aquaculture in the central costal region of Vietnam and to reduce organic pollution in traditional integrated fish farming, a new method was developed called the ‘improved VAC’ In traditional VAC systems the manure from farm animals is released into fish ponds whereas in the ‘Improved VAC’ the manure is used for earthworm culture. The worm production is then used to feed high value fish species in tanks. In this project snakehead fish (Channa maculatus) cultured in tanks and fed partly on earthworms, resulted in an increase in income generation for farmers. The results have shown that the fish growth rate was relatively high, reaching 700 g/fish after 5 months. The FCR for the en tire production cycle was 5.22, 4.75 and 6.14 in demonstrations in Thanh Hoa, Ha Tinh and Quang Tri, respectively. Water quality remained within the acceptable range for fish health with NH3 and NO2 levels in the tanks being significantly lower than those in ponds. Economic analysis indicated that there was a high net profit in all demonstrations with a ROI of 71%, 104% and 41% in Thanh Hoa, Ha Tinh, and Quang Tri respectively. The results demonstrate that culture of snakehead fish in tanks fed a partia l diet of earthworms can increase income to farmers thus other farmers in the region could benefit from adoption of the model. 1. Introduction Integrated farming systems encompassing gardening, fish pond and livestock pen (under Vietnamese acronym VAC ) is the most popular practice in the rural communities of Vietnam and other countries in Asia including China (Vincke, 1997). This farming model is very efficient in terms of recycling of the materials in the system (Bilard et al., 1990). However, the pro ductivity of the aquaculture (pond) component is quite low ranging from a few hundred kilograms to an average 1,500 - 1,700 kg per ha per year (0,015 - 0,017 kg/m2.year) (Kumar et.al, 2003). Aquatic species produced in the traditional VAC systems carry a hig h risk of contamination with organisms such as E.coli and parasites. Acinetobacter spp. that were exposed to the high organic load of the VAC system for two months and isolated from composite water - sediment samples were found to have an increased resistanc e to oxytetracycline and sulfamethoxazole (Andreas Petersen et al., 2002). E.coli , isolated from mothers involved in integrated fish farming were found to have increased antibiotic resistance compared to those isolated from mothers who were not ( Kalter , 2009). Therefore, it would be beneficial for the traditional VAC system to be improved to CARD 027/07 VIE – Demonstration of improved VAC model in Central Vietnam 307 enable increased productivity and reduce potential organic pollution. In the Improved VAC, manures from husbandry or by - product of horticulture are used for the c ulture of earthworms. The earthworms produced are then used as food for high value fish species cultured in tanks and the faeces of the worm is used as fertilizer. This article presents the results from demonstration implementation of the Improved VAC f or the project CARD 027/07VIE. It focuses on the snakehead cultured in tanks fed with trash fish and earthworms. Examination of fish growth rate, the water quality in tanks and economic analysis of the demonstrations are included. 2. Materials and methods The demonstrations of the Improved VAC were implemented in three middle provinces of the country: Quang Xuong - Thanh Hoa, Thach Ha - Ha Tinh and Trieu Phong - Quang Tri. These sites are representative for three socio - eco - systems. The first site, Thanh Ho a, is representative of a small household scale (small garden and ponds with no artificial aeration). The second site is for households who have a higher standard of husbandry and horticulture but no pond. The third site was in Quang Tri and is representa tive of households with a large pond/s but poor water quality, and basic horticulture and husbandry practices. The Improved VAC system includes 30 – 40m3 (height of 60 – 80 cm) of water in concrete tanks or pond (100 – 300 m2), a livestock pen with an are a of 50 - 60m2 which can produce manure for cultivation of earth worms and a vegetable garden (Figure 1). The fish tanks were surrounded with synthetic polymer nets up to 2 m in height to prevent the fish “jumping” out of the tanks when it rains. Indicators to assess efficiency of an Improved VAC include culture water quality and profit generation compared to a traditional VAC. Water quality is evaluated by using parameters such as temperature, DO, NH3, NO2, NO3, BOD, H2S. In traditional VAC these parameters are usually at the high end of acceptable values in the range for growth for aquatic animals. Fig 1. Flow of materials in an Improved VAC: Manures from animal husbandry are not directly released into fish ponds. Instead manure is used for e arthworm culture. During the production cycles, samples were collected for water quality analyses. The sampling was conducted in different positions in tanks, that is, close to the water inlet and outlet and in the centre part of the tank. In the ponds t wo samples were taken, that is, near to the pump and in the centre of the pond. Samples were then tested for NH 3 , NO 2 , pH, DO and hardness by using test kits and laboratory analysis. The results were interpreted in comparison with the traditional VAC and i n accordance with the acceptable range for aquatic animals outlined in the National Standard for Water Quality (TCVN, 1995; 2000) Snakehead (Channa maculatus) was stocked at density of 10 fish/m². The water level in tanks was maintained at 10 – 40 cm in d epth, depending on the size of fish. The system pump was switched on for 1 hour, twice a day. A partial water change was performed on the tanks after every four days of culture. Small snakehead were fed a diet that consisted mainly of earthworms, while l arger fish were fed a diet that consisted of up to 70% trash fish. To meet the system’s quantity requirements, earthworm cultures were initiated 1 month prior to stocking the system with fish. Garden (mainly vegetables) Pum Manures for husbandry or bypr oduct of horticulture Cattle/pig/chicken shed (manures released) Earth worm to culture Semi - bio filter Fish pond (or well to get water) Concret e tanks 20m 2 Water circulated after treated Earthworm shed (12 – 30 m 2 ) Võ V ăn B ình, Đào Văn Phú, Nguy ễ n Quang Chương, Mai Văn Tài, Ravi Fotedar & Jane Fewtrell 308 Economic analysis of the Improved VAC was implemented by value estimation of input (consisting of tanks depreciation, fingerlings, feed), operation cost (pumping and labor costs), and the value of output presented by total production (from selling in markets, for family or as gifts for relatives) multiplied by the pr ice at market. 3. Results and discussions 3.1 Fish growth rate In general, snakehead cultured in tanks in the Improved VAC have grown fast, reaching 700 g/fish (approximately 40.5 cm in length) from the initial size of 12 g (10 cm in length) after about 5 months. Fingerlings fed by ground trash fish grew at the same rate as fingerlings fed a combination of trash fish and earthworm (with ratio of 50:50). However, the condition factor K (K = W*100/L3) of the fish fed the combined feed was higher than the fi sh fed on trash fish only (1.20 compared to 1.12). This indicates that earthworms are suitable food for snakehead. Food conversion rate (FCR) was calculated for the whole culture period in the three demonstrations in Thanh Hoa, Ha Tinh and Quang Tri. Thes e were 5.22, 4.75 and 6.14 respectively. In the beginning of the production cycle, that is from fingerling to 300 g/fish, the FCRs for the combination feed of trash fish and earthworm (50:50) were 3.13; 3.66 and 4.11, respectively. Interestingly, in Ha Tin h the Improved VAC system was managed by well educated persons (both husband and wife were master and bachelor degrees) and the survival rate in this province was higher (97%) than in Thanh Hoa (92%) and Quang Binh (87%) where system managers had less for mal education. This suggests that system knowledge and understanding could be an important factor in the success of the operation. 3.2 Water quality in tanks and ponds The results clearly show that the semi - bio filter operated efficiently, resultin g in lower levels of NO 2 and NH 3 in tanks than those in ponds (Figure 3). NO 2 was lower than 0.1 mg/l in all demonstration sites; which is within the acceptable range for normal growth rate of aquatic species, including snakehead fish. In Quang Tri, for i nstances, the level of NH 4 and NO 2 were low in tanks while in ponds they were sometimes higher than the acceptable limit The value of NH 4 and NO 2 fluctuated between 0.36 – 0.66 mg/l and 0.004 – 0.03 mg/l, respectively (Figure 3). Fig 2 . Growth rat e of snakehead fish in tanks in the Trieu Phong – Quang Tri Improved VAC demonstrations Võ V ăn B ình, Đào Văn Phú, Nguy ễ n Quang Chương, Mai Văn Tài, Ravi Fotedar & Jane Fewtrell 309 Fig 3. Comparison of total Ammonium and NO2 in ponds and in tanks during the production cycle in the Quang Tri demonstration. For snakehead, the concentration of dissolved oxygen does not play such an important role as many for other fish species due to the fact that they p ossess an organ for breathing air. However, the concentration of NH 4 /NH 3 and NO 2 are critical issues to consider because they are toxic to fish at low concentrations. Both trash fish and earthworms which were used to feed the fish in these systems contain high protein levels which are quickly converted into NH 4 /NH 3 and NO 2 within the system. Therefore, levels of NH 4 /NH 3 and NO 2 must be monitored and controlled. The parameters which are not content nitrogen original in production cycle are presented in Table 1. Table 1. Non - nitrogenous water quality measured during the culture of snakehead in Trieu Phong – Quang Tri. (P = Pond, and T = Tank) Water quality parameters Sampling months Apr May Jun Jul Aug Sep P T P T P T P T P T P T Temperature (°C) 25 . 6 23 . 4 32 . 1 27 . 2 33 . 7 27 . 4 33 . 0 27 . 0 32 . 1 28 . 3 31 . 0 27 . 9 pH 7.9 7.8 8.3 7.7 7.8 7.9 8.5 7.6 7.8 7.4 7.7 7.7 DO (mg/l) 5.5 4.2 4.1 3.4 4.0 4.1 3.0 3.4 3.4 4.3 4.2 4.4 dH – Hardness (mg/l) 6 . 8 6 . 5 8 . 0 7 . 0 7 . 8 6 . 8 7 . 3 9 . 7 7 . 6 8 . 6 8 . 3 8 . 2 These parameters we re well within the favorable ranges for snakehead growth. However, it is important to monitor and control these parameters as they (particularly temperature and pH) influence the concentration and availability of the nitrogenous parameters. Values of DO an d hardness were low, ranging between 3.4 – 4.4 mg/l and 6.5 – 8.6 respectively. 3.3 Economic analysis Economic analyses have shown a good profit from all demonstrations, regardless of the fact that, due to the time restrictions of the project, the statist ics on which the analyses were based were limited to a one year production cycle. From the results obtained from the demonstrations, it can be seen that the Improved VAC system has potential to Võ V ăn B ình, Đào Văn Phú, Nguy ễ n Quang Chương, Mai Văn Tài, Ravi Fotedar & Jane Fewtrell 310 financially benefit farmers using the integrated system in Ce ntral coastal provinces. The results of analysis have shown that the average return on investment (ROI) of snakehead culture in tanks was high, suggesting that the model can generate income and benefit to famers. The demonstration in Ha Tinh gave a ROI ind ex of 104% (Table 2) while in Thanh Hoa and Quang Tri were lower, at 71% and 41% respectively (Table 3). The largest proportion of expenditure was for feed, occupying 47.1%; followed by tanks depreciation (10.3%) and cost of the fingerlings (8.2%). Earthwo rms replaced a large portion of the feed so feed costs would have been higher using the traditional VAC. Table 2. Economic analysis – detail of input and output for the demonstration in Th ạ ch Bàn – Th ạ ch Hà – Hà T ĩnh Expenditure Value (VND) Tank deprecia tion (2 tanks x 20 m²) 1.000.000 Pump cost 150.000 Pumping cost (for circulation) 400.000 Fingerlings stocked (2000 fish) 800.000 Feed (trash fish) 4.568.000 Labor cost (for 4 months) 2.780.000 Total input 9.698.000 Total output 19.851.000 Net profit 10.153.000 Return on investment (%) 104 Table 3. Economic analyses of demonstrations in Thanh Hoa, Ha Tinh and Quang Tri provinces Economic parameters Demonstration Thanh Hóa Hà T ĩnh Qu ả ng Tr ị Tanks area (m²) 18 20 20 Days of culture 147 139 158 Output (VND million) 8,095 19,851 10,368 Output (VND million) 4,766 9,698 7,334 Net profit (VND million) 3,392 10,153 3,034 Return on Investment (ROI) 0,71 1,04 0,41 3.4 Poten tial of snakehead culture in tanks 3.4.1 Advantages and disadvantages There are several advantages of culturing snakehead in tanks: 1) When compared to pond aquaculture, culture of fish in tanks requires a relatively small area, thereby most households in the middle coastal areas can easily include aquaculture in their integrated farming system. 2) Trash fish, as feed for snakehead, is readily available in the coastal areas and it is relatively cheap. Additionally, in the case of limited supply of trash fish (e.g . weather disturbance such as a typhoon) earthworms from the Improved VAC can be used as an alternative feed. 3) The culture conditions in tanks can be easily manipulated and therefore the alteration of cycles to suit individual situations and changes in t he market is possible. 4) Aquaculture in tanks requires relatively little water, thus, the operation cost for CARD 027/07 VIE – Demonstration of improved VAC model in Central Vietnam 311 recirculation are reduced. Also, in some areas, for example in Quang Tri, water that meets the standard of quality for aquaculture is scarce, therefore effective recirculating systems would be beneficial in such areas. 5) Snakehead can be stocked in tanks at high density. For example stocking densities of up to 50 – 70 fish/m² are possible and can give productivity of 40 – 60 kg/m² without cr eating poor water quality in the system. However, the culture in tanks also has some disadvantages. The fish are easily harvested which may lead to problems with theft, which is common in rural areas. Also, the culture of snakehead in tanks requires relati vely advanced technology, so farmers must be trained so that the system operates efficiently an d costs are kept to a minimum. 3.4.2 Environmental aspect a. Within system Snakehead are tolerant to low DO levels as they possess air - breathing organs on sides of the head (Munshi et al., 1994). However, with high concentration of BOD and COD as found in ponds, the fish will be susceptible to Epizootic Ulcerative Syndrome (G. N. Frerichs, 1993). A properly functioning filtration system (i.e. Improved VAC) will ad dress issues with dissolved organic material in the water therefore, decreasing the opportunity for disease to infect the culture. Iron levels are another concern for snakehead in tanks. Past experience and sampling has shown that high iron levels in cultu re water correlated with an increase on snakehead mortality In addition, results suggest that the growth rate of fish and FCR has a negative correlation with increasing iron concentration. This was presented clearly in the Quang Tri demonstration, where the iron concentration was relatively high (> 3 mg/l)and the growth performance and survival of the fish were low when compared to those found in the systems in Thanh Hoa and Ha Tinh. b. Surrounding environment Culturing snakehead in tanks has three major advantages over pond aquaculture from an environmental impact perspective; 1) Less effluent is released into the environment and, if release is necessary, it is generally of a less polluting nature. 2) Less water is required which is beneficial in areas of limited water supply. 3) Less physical damage to the environment resulting from construction. Furthermore, culturing snakehead in tanks is clean and is not associated with the bad odor that can accompany animal husbandry. 3.4.3 Economic aspect The ec onomic efficiency of snakehead culture in tanks is assessed based on the margin of the production cost and production value at market. Unlike many fish species, the price gap of snakehead between farm gate and end users is not very high because snakehead c an be transported and kept very easily without mortality. Despite this the economic efficiency of the culture is very high. More profit would be possible if the farmers were to sell their produce directly to restaurants The economic analysis of the cultur e of snakehead in tanks eliminated the notion that aquaculture is only possible in ponds. Farmers now have evidence that they can include aquaculture into their integrated farming system with space of just 50 m². 4. Conclusions and recommendation s 1. It ha s been shown that snakeheads have a high growth rate in tanks, reaching to 700 g/fish after 5 months culture. 2. From demonstrations, it can be concluded that the Improved VAC system is suitable for most situations in the central coastal area of Vietnam. It w ould be beneficial for this model to be transferred to other farmers through the extension system. 3. Water quality parameters tested during the culture indicated a suitable range for growth of aquatic animals, including for snakehead fish. Võ V ăn B ình, Đào Văn Phú, Nguy ễ n Quang Chương, Mai Văn Tài, Ravi Fotedar & Jane Fewtrell 312 Võ V ăn B ình, Đào Văn Phú, Nguy ễ n Quang Chương, Mai Văn Tài, Ravi Fotedar & Jane Fewtrell 313 Reference 1. Tiêu chu ẩn Nh à Nư ớc Việt Nam năm 1995 (TCVN 5942 - 1995, TCVN 5992 - 1995, TCVN 5993 - 1995, TCVN 5994 – 1995 và TCVN 5996 – 1995) và năm 2000 (TCVN 6774:2000). 2. Andreas Petersen, Jens Strodl Andersen, Tawatchai Kaewmak, Temdoung Somsiri, và Anders D alsgaard, 2002. Impact of Integrated Fish Farming on Antimicrobial Resistance in a Pond Environment. Applied and Environmental Microbiology, December 2002, p. 6036 - 6042, Vol. 68, No. 12 3. Billard, R.N. De Pauw, J.C. Micha, C. Salomoni, and J. Verreth (1990). The impact of aquaculture in rural management. In: Aquaculture Society. Special Publ. No. 12, N. De Pauw and R. Billard (Eds) Bredene, Belgium 4. G. N. Frerichs, S. D. Millar and Supranee Chinabut , 1993. Clinical response of snakeheads (Ophicephalus striatus ) to experimental infection with snakehead fish rhabdovirus and snakehead cell line retrovirus . Published by Elsevier Science B.V. 5. Henry D. Kalter, Robert H. Gilman, Lawrence H. Moulton, Anna R. Cullotta, Lilia Cabrera, AND Billie Velapatiño, 2009. Risk Fa ctors for Antibiotic - Resistant Escherichia coli Carriage in Young Children in Peru: Community - Based Cross - Sectional Prevalence Study. Am. J. Trop. Med. Hyg., 82(5), 2010, pp. 879 - 888. 6. Munshi JS , Roy PK , Ghosh TK , Olson KR ., 1994. Cephalic circulation in the air - breathing snakehead fish, Channa punctata, C. gachua, and C. marulius (Ophiocephalidae, Ophiocephaliformes) . MeSH – Anat Rec. Department of Zoology, Bhagalpur University, Indi a 7. Vincke M. M. J., 1997. Integrated farming of fish and livestock: Present stutus and future development. F.A.O. Rome. 8. Michael Poxton, 2003. Water Quality In Aquaculture Farming Aquatic Animals and Plants. Fishing (Ed. by John S. Lucas and Paul C. Southgat e), pp. 47 - 73 News Books a blackwell Publishing company . . AND IMPROVE INCOME FOR FARMERS IN THE CENTRAL COASTAL VIE TNAM Project title: Improving traditional integrated farming systems (VAC) - a new livelihood option for poor farmers in the coastal communities Project. kits and laboratory analysis. The results were interpreted in comparison with the traditional VAC and i n accordance with the acceptable range for aquatic animals outlined in the National Standard. requires a relatively small area, thereby most households in the middle coastal areas can easily include aquaculture in their integrated farming system. 2) Trash fish, as feed for snakehead, is readily available