A thesis submitted in partial fulfillment of the requirements for the degree of bachelor of aquaculture science

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CAN THO UNIVERSITY COLLEGE OF AQUACULTURE AND FISHERIES STUDY ON SEED PRODUCTION OF FIRE EEL (Mastacembelus erythrotaenia) By NGUYEN TAN DUY A thesis submitted in partial fulfillment of the requirements for the degree of Bachelor of Aquaculture Science Supervisor Dr. BUI MINH TAM Can tho, December/2013 Approvement of supervisor Approvement of student Acknowledgements I would like sincerely to thank the administrators of Can Tho university, freshwater hatchery technicians and all teachers in college of aquaculture and fishery. I would like sincerely to express gratefulness to my advisor Dr. Duong Thuy Yen who has created the best condition and has taught precious knowledge for me during studying at college. I would like sincerely to thank Dr. Bui Minh Tam and M.Sc. Le Son Trang who have helped and have transmitted guidance for me to finish this thesis. I would like sincerely to thank my parents, relatives and my friends who have encouraged and helped me during doing this thesis. Thank sincerely! i Abstract Fire eel is scarce and new fish species in Mekong river delta. The external shape of fire eel is very beautiful and can be used for decoration. There are not many studies on artificial propagation of this species and it is only exploited from nature, therefore study on seed production of fire eel is implemented. Research is implemented from june 28 to December 22 in 2013. The content of research includes: (1) Stimulate artificial propagation of fire eel by combining HCG and pituitary gland hormone and(2) Rearing larvae by different feeding regimes. In research on artificial propagation of fire eel females were injected 4 times. The first two injections were induced at 500 IU/kg of HCG, the interval between them was 24 hours. After 24 hours the third dosage was induced at 1500 IU/kg of HCG combined with 2 mg/kg of pituitary gland. After 10 hours, the final dosage was induced at 4000 IU/kg of female. The result indicated that the response time was 15 to 16 hours, ovulation rate reached 100%, relative fecundity reached 8419 ± 244.21 eggs/kg, fertilized rate achieved 94.8 ± 3.59 %, hatching rate reached 52.88 ± 17.41 %, time of embryo development was 58 to 60 hours, the interval of yolk sac’s completely absorption was 12 days. The larval rearing experiment was 35 days. Moina was fed to larvae till 5th, then changed to tubifex worm. There are 4 treatments including (1) Tubifex worm was completely fed to larvae in 35 days and treatment 2, 3, 4, tubifex worm was fed to larvae till 15th, 20th, 25th then changed to home made feed. Result indicated that there was significant difference (p<0.05) between treatments. Treatment 1 resulted in highest growth rate and survival rate (final weight 0.98 ± 0.2 g, final length 6.454 ± 0.57 cm, and survival rate 98 ± 2 %). Treatment 2 had lowest effective in term of growth rate and survival rate (final weight 0.158 ± 0.078 g, final length 3.685 ± 0.5 cm, and survival rate 78 ± 5.29 %). The result confirmed that tubifex worm is the best feed for larval rearing, home made feed should be provided at higher days old of larvae. ii Table of Contents Acknowledgements .............................................................................................................. i Abstract ............................................................................................................................... ii Table of contents ................................................................................................................ iii List of figures ..................................................................................................................... vi List of tables ..................................................................................................................... viii List of abbreviations ........................................................................................................... ix CHAPTER 1: INTRODUCTION ........................................................................................ 1 1.1 Research objective ..................................................................................................... 3 1.2 Research contents ...................................................................................................... 3 CHAPTER 2: LITERATURE REVIEW .............................................................................. 4 2.1 Scientific classification and morphology of fire eel .................................................... 4 2.1.1 Taxonomy ........................................................................................................... 4 2.1.2 Morphology ........................................................................................................ 4 2.2 Distribution ................................................................................................................ 5 2.3 Feeding ...................................................................................................................... 5 2.4 Environmental condition ............................................................................................ 6 2.5 Reproduction ............................................................................................................. 6 2.6 Reproductive Seasonality in fish ................................................................................ 6 2.7 Relationship between nutrient accumulation and development of gonad .................... 6 2.8 Scientific basis of fish reproduction stimulation ......................................................... 7 2.9 Hormone used in stimulating fish propagation ........................................................... 8 2.9.1 Using pituitary to stimulate artificial propagation ................................................ 8 2.9.2 Using HCG to stimulate artificial propagation ..................................................... 8 2.9.3 Using ovaprim to stimulate artificial propagation ................................................ 8 2.10 Researches in artificial propagation and larval rearing of Mastacembelidae family .. 8 3.1 Material ................................................................................................................... 12 3.1.1 Experimental site............................................................................................... 12 iii 3.1.2 Experimental time. ............................................................................................ 12 3.1.3 Equipment ......................................................................................................... 12 3.1.4 Chemical ........................................................................................................... 12 3.2 Research methodology ............................................................................................. 12 3.2.1 Stimulate maturation of broodstock ................................................................... 12 3.2.2 Stimulating artificial propagation of fire eel ...................................................... 14 3.2.2.4 Method for incubation .................................................................................... 18 3.2.3 Larval rearing experiment of fire eel ................................................................. 18 3.2.6 Data collection method ...................................................................................... 20 3.2.6.1 Data collection in broodstock conditioning ................................................. 20 3.2.6.2 Data collection in stimulating artificial propagation ................................... 21 3.2.6.2 Data collection in larval rearing .................................................................. 21 3.3 Data analysis ............................................................................................................ 22 CHAPTER 4: RESULT AND DISCUSSION .................................................................... 23 4.1. Environmental factors in broodstock conditioning .................................................. 23 4.1.1 Temperature ...................................................................................................... 23 4.1.2 pH ..................................................................................................................... 24 4.2 Stimulate artificial propagation by HCG and pituitary gland hormone ..................... 25 4.3 Embryo development of fire eel ............................................................................... 28 4.4 Larval rearing experiment ........................................................................................ 31 4.4.1 Environment factors in larval rearing experiment .............................................. 31 4.4.2 Growth rate in length of larvae .......................................................................... 32 4.4.3 Growth rate in weight of larvae ......................................................................... 35 4.4.5 Survival rate of larvae ....................................................................................... 37 CHAPTER 5: CONCLUSIONS AND RECOMMENDATIONS ....................................... 39 5.1 Conclusions ............................................................................................................. 39 5.2 Recommendation ..................................................................................................... 39 REFERENCES .................................................................................................................. 40 APPENDIX ....................................................................................................................... 42 iv List of figure List of figure page Figure 2.1: Morphology of male and female .............................................................. 4 Figure 2.2: Effect of ecological and physiological factor in natural reproduction ....... 7 Figure 3.1: Composite tank for broodstock conditioning .......................................... 13 Figure 3.2: PVC for hiding of fire eel ...................................................................... 13 Figure 3.3: Frozen shrimp is the main feed for broodstock ...................................... 14 Figure 3.4: Morphology of female’s genital hole ..................................................... 14 Figure 3.5: HCG and pituitary gland hormone ......................................................... 15 Figure 3.6: Inject female fire eel .............................................................................. 16 Figure 3.7: Stripping female’s egg ........................................................................... 17 Figure 3.8: Stripping male’s sperm into needles....................................................... 17 Figure 3.9: Artificially fertilizing fire eel’s egg ........................................................ 17 Figure 3.10: Spreading egg evenly out all the net ..................................................... 18 Figure 3.11: Net frame is flooded in water ............................................................... 18 Figure 3.12: Initial length at stocking of fire eel larvae ............................................ 19 Figure 3.13: Home made feed is pressed to pill before feeding ................................ 20 Figure 3.14: Setting up larval rearing experiment of fire eel .................................... 20 Figure 4.1: Temperature fluctuation in broodstock conditioning .............................. 24 Figure 4.2: pH fluctuation in broodstock conditioning ............................................. 25 Figure 4.3: The difference in color between fertilized and unfertilized egg .............. 27 Figure 4.4: Fungi the reason for low hatching rate ................................................... 27 v Figure 4.5: External shape of fire eel larvae after yolk sac’s absorption ................... 28 Figure 4.6: Measuring length of newly hatch larvae of fire eel ................................. 29 Figure 4.7: Development of fire eel’s embryo .......................................................... 29 Figure 4.8: Mean final length of larvae in 4 treatments ............................................ 33 Figure 4.9: Relationship between day and length of larvae in control treatment ....... 34 Figure 4.10: Measuring final length after 35 days of rearing .................................... 34 Figure 4.11: Mean final weight of larvae in 4 treatments ......................................... 36 Figure 4.12: Relationship between day and weight of fish in control treatment ........ 37 Figure 4.13: Mean survival rate of larvae in 4 treatments ......................................... 38 vi List of table List of table page Table 3.1: Stimulating propagation by HCG and pituitary gland ...................................... 16 Table 3.2: Rearing larvae by different feeding regimes .................................................... 19 Table 4.1: Temperature in broodstock conditioning ......................................................... 23 Table 4.2: pH in broodstock conditioning ........................................................................ 24 Table 4.3: Reproduction indexes of fire eel after stimulating artificial propagation .......... 25 Table 4.4: Development of fire eel’s embryo ................................................................... 30 Table 4.5: Environment factors in larval rearing experiment ............................................ 31 Table 4.6: Growth rate in length of larvae ........................................................................ 32 Table 4.7: Growth rate in weight of larvae ...................................................................... 35 Table 4.8: Survival rate (%) of larvae .............................................................................. 37 vii List of abbreviations g Gram mm Milimeter cm Centimeter kg Kilogram HCG Human chorionic gonadotropin LHRH-A Luteotropin hormone releasing hormone analog FSH Follicle stimulating hormone LH Luteinizing hormone DA Dopamine IU International unit SD Standard deviation M Morning A Afternoon W Weight L Length viii CHAPTER 1: INTRODUCTION Aquaculture is more and more developing in the world. In Viet Nam aquaculture is developing and has an important role in economics of the country bringing large income for people and country. Seafood export earns 6,130,000,000 dollars in which shrimp products earn 2,240,000,000 dollar, tra catfish products earn 1,700,000,000 dollars. Therefore, aquaculture has contributed 3.1-3.7% GDP, also according to department of aquaculture in July 2012 production of capture and aquaculture reaches 531,300 ton in which fish products reach 379,200 ton and shrimp products reach 101,200,000 ton. Production of aquaculture in july 2012 reaches 344.200 ton in which fish products reach 232,600 ton and shrimp products reach 91,800,000 ton. Water surface area for aquaculture in 2012 reaches 1,059,000 ha and it is predicted that in 2013 water surface area for aquaculture will reach 1,200,000 ha (Department of Aquaculture in 2012). Mekong river delta is a key economic area in producing aquaculture and agricultural products of Viet Nam. Aquaculture activities in Viet Nam are well developed in Mekong river delta because this area accounts for a large production and water surface area of the country. Areas for aquaculture in Mekong river delta is 709,980 ha, total production for aquaculture reaches 1,014,590 tons accounting for 72% total aquaculture production of country (Department of Aquaculture in 2012). With complex river and canal systems and there are two seasons including flood season and dry season each year, Mekong river delta creates good conditions for growth of many fresh water fish species in which Tra Catfish is major export commodities of this area. In 2012 tra catfish culture area reaches 5,910 ha, production reaches over 1,280,000 tons and export value reaches 1,740,000,000 dollars. However, recently there are difficulties due to market price, so farmer tends to culture other different native species that also have high economic value. In addition to demand about meaty fish, many consumers are even interested in playing ornamental fish which they culture for decoration. Therefore there is higher and higher requirement about ornamental fingerling for export. Fire eel which has scientific name Mastacembelus erythrotaenia is a new ornamental fish species. They are fresh water species and widely distribute in Southeast Asia such as India, Malaysia, Myanmar, Sri lanka, Thailand, Indonesia, Cambodia, Lao, and Viet Nam. Requirement about environment condition is not very strict with this species because they can survive in temperature range 24-28 oC, pH 6.5-7.5, hardness 121 15 dH. In nature fire eel can reach 1.2 meters in length. Feed for fire eel is easy to find such as prawn, brine shrimp, mussel, bloodworms and frozen foods. Because of these reasons fire Eel is very suitable to be cultured in Mekong river delta. Fire eel could be cultured for decoration in house because it is very beautiful ornamental fish species. Moreover, it also has high economic value because in market fire eel with sizes of 15-20 cm has price from 75,000-100,000 VND. However, there are not much researches about this species especially in artificial reproduction techniques. In addition, the demand of consumers for this species is higher and higher while the number of fingerling is limited and only exploited from nature. Because of this reason, research on seed production of Fire eel is conducted. The success of this research will contribute in artificial propagation process of fire eel to meet the fingerling demand of consumers. 2 1.1 Research objective: Study on seed production of this species needs to be conducted and applied to recover these populations and meet demand of consumers. Immediately two main objectives need to be reached including: (1) determine the total dosage of hormone and the number of injection time to induce ovulation of fire eel, (2) determine the suitable feeding regime for larval rearing. 1.2 Research contents: 1. Conditioning broodstock in capture conditions. 2. Stimulating artificial propagation of fire eel by HCG and pituitary gland. 3. Rearing larvae by different feeding regimes. 3 CHAPTER 2: LITERATURE REVIEW 2.1 Scientific classification and morphology of fire eel 2.1.1 Taxonomy According to Truong Thu Khoa and Tran Thi Thu Huong (1993) fire eel belongs to: Kingdom: Animalia, Phylum: chordate Class: Actinopterygii Order: Synbranchiformes Family: Mastacembelidae, Genus: Mastacembelus Species: Mastacembelus erythrotaenia. English name: fire eel 2.1.2 Morphology Figure 2.1 a: Female fire eel Figure 2.1 b: Male fire eel Fire eel has small and flat head, snout is long and pointed as short beard in the front side. Tooth is small and fine, small eye under skin slant to half over the head and near the tip of snout. In front of eye there is one pointed thorn toward behind. Forehead between two eyes is narrow, flat, nearly 1.5 times eye diameter, gill’s hole is small. The 4 body is long with pipe-shape, the belly is round and the tail part is quell. The scale is small, fine, cover all body and a head part. Origin of dorsal fin is long, in front of dorsal fin there is 31-32 thorn, final thorn is biggest and longest. The skin membrane between thorns just presents at the origin. Behind, the soft ray is stick together by skin membrane and thick muscle. Anus fin has three thorns, the first thorn is small and short, the second thorn is big and long, the third thorn is in muscle. The soft rays have the same structure as back fin. Starting point of back fin soft ray is horizontal with starting point of anus fin soft ray. Pectoral fin is round and small, tail fin is very small and stick with anus fin and dorsal fin. There is no abdomen fin(Truong Thu Khoa and Tran Thi Thu Huong, 1993). Fish has color of gray-green or slightly black. There is red round small spots run from the later head to the end of tail stalk. Upper and below these spots has 2-3 paleyellow stripes. The peak of dorsal fin, anus fin, caudal fin has yellow color and many yellow round small spots. Origin of thorn of dorsal fin has red color. Origin of caudal fin has one small black spot (Truong Thu Khoa and Tran Thi Thu Huong, 1993). The fire eel can grow up to a very considerable size in the wild with specimens often exceeding 1.2 meters (3.9 ft) in length. However, due to limiting factors in the captive environment they usually reach a maximum of around 55 centimeters (22 in) even in very large aquaria. 2.2 Distribution Fire eel is widely distributed in south-east Asia such as India, Malaysia, Myanmar, Sri Lanka, Thailand, Indonesia, Cambodia, Lao, Viet Nam. Fire eel inhabits usually sluggish lowland waters including floodplains and slow current (Truong Thu Khoa and Tran Thi Thu Huong, 1993). 2.3 Feeding Fire eel is omnivorous but mainly carnivorous and consumes a variety of smaller fish, aquatic invertebrates, plant matter and detritus. They prefer meaty foods such as prawn, brine shrimp, krill, mussel, mosquito larvae, bloodworms, cyclops and lancefish. Live and frozen foods can also be fed, however these foods alone are unlikely to be enough to sustain larger fish. Some specimens will also accept vegetable matter, although this is fairly rare. They are also bottom-feeder and predator that spend large portions of their time buried in the riverbed and they are active in the night time. Fire eel often likes hiding in rock and digging substrate such as gravel, sand to hide. Moreover, they also like eating roots of floating plants and this aquatic plant can reduce light intensity that fire eel does not want to expose. So in culture of fire eel rock, gravel, sand and floating plants need to be provided. 5 2.4 Environmental condition Fire eel is fresh water fish, the demand about water quality for growth of fire eel is not very strict, the temperature range is about 24-28 0C, hardness is from 2-15 ppm, pH range is from 6.5-7.5. 2.5 Reproduction Fire eel lays egg only and egg will hatch after 3-4 days, Captive spawning is rare and extremely difficult, even with mature fish over 20 inches (51 cm). Use a large tank with a pH around 7.0, water hardness from 10–15 dH, and a temperature from 27–29 °C (81–84 °F). Fish lays 800–1,200 eggs in aquatic plants. The eggs are clear and measured around 1 millimeter (0.039 in) in size. 2.6 Reproductive Seasonality in fish According to Pham Minh Thanh and Nguyen Van Kiem(2009) the development of gonads undergos 6 stages, spawning of fish occurs when physiological and ecological conditions are favorable for fish. When fish gets matured and meets suitable environment conditions for development and existence of larvae and embryos, fish will reproduce. In contrast, if fish gets matured but ecological and physiological conditions are not suitable, fish will not reproduce. This indicates that environmental and ecological factors affect maturation and gonad development of fish, but environmental and ecological factors are affected by climate, weather and season. Therefore, there is close relation between each period of year with each development stage of fish’s gonad. Due to variation of environmental factors relates to seasonal climate change that almost fish species in Mekong river delta have gonad in stage II in December and January, stage III in February and March, stage IV in April and May. Therefore, development of gonad following cycle is basis for aquaculturists construct plan for culturing broodstock effectively, from here avoid culturing very early (loss cost) or very lately. 2.7 Relationship between nutrient accumulation and development of gonad According to Pham Minh Thanh and Nguyen Van Kiem (2009) in development of gonad and ovary fish needs to be provided with enough nutrients. These nutrients one part will be structure of body, the other part is accumulated in organizations as liver and muscle in form of Lipid and Glycogen. They are also used to provide energy for activities of daily life. Many researches indicated that reproductive cells grow up thanks to nutrient metabolism from muscle and liver. This nutrient metabolism consumes energy and it is provided by feed. Therefore, nutrient accumulation in fish is important basis for nutrient metabolism into gonad gland. 6 According to Winberg (1968) cited by Pham Minh Thanh and Nguyen Van Kiem (2009) diet in broodstock conditioning needs to be suitable and balanced. High or low diet is not good for gonad development of broodstock, when increasing diet fecundity will increase to a point and then stop and if continue to increase, fecundity decreases. This is basis explaining why at the end of broodstock conditioning diet is reduced. According Pham Minh Thanh and Nguyen Van Kiem (2009) nutrients which are mobilized from muscle, liver to gonad gland are protein and lipid, this is basis for at the end of broodstock conditioning protein and lipid content (%) are increased in diet. 2.8 Scientific basis of fish reproduction stimulation There are two factors affecting to fish’s reproduction consist of ecological factor and physiological factor (Pham Minh Thanh and Nguyen Van Kiem, 2009), ecological factors are environmental conditions as flow, dissolved oxygen, rain while physiological factors are hormones that affect directly or indirectly on fish’s gonad. Ecological factors are necessary condition for creating physiological factors. However, decision for fish’s reproduction is belong to physiological factors. One more another important condition for fish’s reproduction is maturation of gonad. If ecological or physiological factors appear but fish’s gonad doesn’t get matured reproduction does not occur, and on the contrary if fish’s gonad is matured but ecological and physiological factors do not occur, fish’s reproduction also does not occur. According to Pham Minh Thanh and Nguyen Van Kiem (2009) if fish gets matured but fish could not be stimulated artificial reproduction, ovary will be degenerated after 15-20 days, so it is basis for choosing the most suitable period to stimulate artificial reproduction. The following diagram shows role and mechanism of ecological and physiological factor in natural reproduction: Ecological signals Sensory organ Central nervous GnRH DA FSH Environment Gametes Gonad Pituitary LH Figure 2.2: Effect of ecological and physiological factor in natural reproduction Base on the above diagram ecological signal will impact central nervous to secrete GnRH and DA, GnRH will stimulate pituitary to secrete gonadotrophic as FSH and LH. In contrast DA will inhibit pituitary from secreting gonadotrophic FSH and LH. FSH 7 hormone stimulates yolk sac formulation and LH stimulates ripe and ovulation (Pham Minh Thanh and Nguyen Van Kiem, 2009). 2.9 Hormone used in stimulating fish propagation 2.9.1 Using pituitary to stimulate artificial propagation Pituitary gland is used firstly in 1930 in artificial propagation experiment. Pituitary gland contains a large number of 2 hormones as FSH and LH that have direct impact on gonad gland and to stimulate yolk sac formulation and cause ripe and ovulation (Pham Minh Thanh and Nguyen Van Kiem, 2009). 2.9.2 Using HCG to stimulate artificial propagation HCG usually called Human Chorionic Gonadotropin Hormone or placenta hormone, it has function like LH hormone that has direct impact on gonad gland and cause ripe and ovulation. HCG is used firstly to stimulate artificial propagation in 1936 by Morozoa (Pham Minh Thanh and Nguyen Van Kiem, 2009). 2.9.3 Using ovaprim to stimulate artificial propagation Ovaprim is a mixture of 20 ug sGnRH-A and 10 mg Domperidon in 1 ml propylene glycol, ovaprim has indirect effect on gonad of fish, ovaprim stimulates pituitary to secrete internal gonadotropin including FSH and LH while HCG and pituitary hormone have direct effect on gonad of fish by providing external gonadotropin such as FSH and LH. 2.10 Researches in artificial propagation and larval rearing of Mastacembelidae family In Viet Nam there has been the first research about artificial propagation of fire eel in Aquaculture Research Institute 2 coordinated with national center for freshwater fisheries seed of southern. The result indicated that broodstock with average weight over 100 g was cultured for maturation in cement tank, and was fed on frozen shrimp and fresh death shrimp, feeding rate was 3-5 % body weight. After culturing 4-5 months they got matured and ready for spawning. HCG was used in this research to stimulate propagation of fire eel and the result indicated that eggs ovulated after 10 hours injection at the temperature of 28-30 oC, ovulation rate reached 50 %. At the temperature of 26-28 o C after 64 hours egg hatched. This result provides basis information for the next researches, it shows that HCG has strong effect on propagation performance of fire eel. Because fire eel is very new species, so research results about fish species that have the same family or genus could be referenced. 8 Another research was also conducted at freshwater hatchery belonging to college of aquaculture and fisheries in Can Tho University. In this experiment two hormone pituitary gland and LHRH-a + Dom were combined to stimulate artificial propagation in Macrognathus aculeatus. The preliminary dosage was pituitary with dosage of 0.3 mg/kg female, the final or the resolving dosage was LHRH-a + Dom with dosage of 200 ug LHRH-a + 10 mg Dom /kg female. The male was not injected, the interval between two injections was 8 hours, the response time was 10-12 hours. The result indicated that relative fecundity reached 26,700-37,800 eggs/kg female, fertilized rate reached 94 %, hatching rate reached 37.9%, the hatching time was 38-42 hours, the interval of yolk sac’s absorption was 3 days. In larval rearing experiment, zooplankton was fed to larvae in the first 2 days, then changed to moina till day 9 th. Tubifex worm was fed to larvae from day 9th till day 40th. Result indicated that daily weight gain reached 0.077 g/day, daily length gain reached 0.213 cm/day, survival rate achieved 10.7% (Huynh Nha Trang, 2006). Experiment stimulating artificial propagation in Macrognathus siamensis Gunther, 1861 was conducted by Duong Tran Trung Kien (2007) in Can Tho. Experiment was designed with 3 different dosages of HCG such as 1500, 2000, and 2500 IU/kg female. The result indicated that the ovulation rate was 86-100%, the response time was 6 hours to 8 hours 40 minutes, the relative fecundity was 49,049 to 68,742 eggs/kg female, fertilized rate was 58 to 69 %, hatching rate reached 49 to 56 %, hatching time reached 34 to 40 hours, the interval of yolk sac’s absorption was 3 days. Dosage 1500 IU/kg female was the most effective one in which the relative fecundity reached 53,029 to 68,742 eggs/kg female, fertilized rate reached 62 to 69 %, hatching rate was 52-56 %. In research conducted by Nguyen Quoc Dat (2007) HCG was used to stimulate artificial propagation in Macrognathus siamensis, there were three dosages of HCG corresponding to 1500, 2000, and 2500 IU/kg of female, female was injected 2 times, the interval between two injection times was 10 hours, the preliminary dosage was 1/3 of total dosage, and the resolve dosage was 2/3 of total dosage. The result showed that ovulation rate was 100% in 3 treatments, the response time was 10h-10h30, fertilized rate reached from 77.80-83.93 % and reached highest in treatment 1500 IU with 83.93 %. The hatching rate achieved from 55.3-56.4 % but there was no significant difference (p>0.05) in hatching rate, the result indicated that treatment 1500 IU was the most effective dosage. In larval rearing experiment egg yolk was fed to larvae in the first 3 days then changed to moina till day 8th. Tubifex worm was fed to larvae from day 9th till day 30th. Result indicated that final length reached 46.52-57.21 mm, final weight achieved 0.480.86 g, survival rate reached 56.57-96.97 %. 9 The research on artificial propagation of Mastacembelus favus was conducted at freshwater hatchery belonging to college of aquaculture and fisheries in Can Tho, there were two experiments with three replications each treatment. In the first experiment there were three treatments corresponding with three different injection times at 2,3 and 4 injection time to compare about ovulation rate and relative fecundity among treatments. Fish was injected 500 IU/kg of HCG at preliminary dosage, and at resolving dosage fish at three treatments was injected at 2000 IU/kg of HCG. In the second experiment there were three treatments corresponding with 3 different dosages of HCG as 1000 IU/kg female, 2000 IU/kg female, and 3000 IU/kg female which were in resolve injection, the number of injection times was resulted from experiment 1. The result indicated that in experiment 1 there was significant difference (p<0.05) among different injection times, third injection time was seen to have highest effect in which ovulation rate reached 100%, relative fecundity reached 21,189 eggs/kg female. In experiment 2 there was no significant difference (p>0.05) among treatments, the ovulation rate of all treatments reached 100 % and relative fecundity, fertilized rate were not significant different among treatments. However, treatment injected at 3000 IU/kg female was the most effective one because time was shortest, hatching rate was highest with 73 % (Ngo Thi Kieu Ngan, 2008). In other research on artificial propagation of Mastacembelus favus, female was injected three times, in the first two injection times female was injected at 500 IU/kg of HCG, the interval between the first two injection times was 24 hours, after 12 hours from the second dosage female was injected the resolving dosage at 3000 IU/kg of HCG, 4 mg/kg of pituitary gland, 0.5 ml/kg of ovaprim. The result indicated that ovulation rate had significant difference (p<0.05), the ovulation rate in treatment using HCG and Ovaprim was 50 % that was lower than treatment using pituitary gland with 100% of ovulation rate, the response time was shortest in treatment using pituitary at 4 hours 13 minutes. The relative fecundity was significant different (p<0.05) among 3 treatments (p<0.05), relative fecundity in treatment using HCG was highest with 10,196 eggs/kg female, next was treatment using pituitary gland with 7,443 eggs/kg female, and the lowest fecundity was belong to treatment 3 with 3,474 eggs/kg female. Fertilized rate had significant difference (p<0.05) among 3 treatments, fertilized rate in treatment 1 was highest with 38.12 %, in treatment 2 was 18.12 %, and in treatment 3 was 0 % (Tran Hoang Diem, 2009). Base on the above result HCG and pituitary were seen to have higher effect than Ovaprim on reproduction performance. Research on artificial propagation of Mastacembelus favus was conducted in national seed center of southern. Broodstock was collected from nature in two provinces 10
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