Báo cáo nghiên cứu nông nghiệp " review of Common carp breeding program at RIA1-VN "

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Common carp is one of the most important cultured species in Vietnam. The goal of the carp breed program was creation of a common carp breed with stable genetic qualities such as fast growth, high survival rate and attractive appearance. In the first phase (1981-1985) the program focused on the assessment of the original carp varieties, which should be used as initial materials for selection. In the second phase (1986-1995) mass individual selection has been carried out among the three hybrid stocks obtained by crossing among Vietnamese white carp, Hungarian scale carp and Indonesian yellow carp....

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1 review of Common carp breeding program at RIA1-VN Mr. Nguyen Huu Ninh, RIA1 Sumary Common carp is one of the most important cultured species in Vietnam. The goal of the carp breed program was creation of a common carp breed with stable genetic qualities such as fast growth, high survival rate and attractive appearance. In the first phase (1981-1985) the program focused on the assessment of the original carp varieties, which should be used as initial materials for selection. In the second phase (1986-1995) mass individual selection has been carried out among the three hybrid stocks obtained by crossing among Vietnamese white carp, Hungarian scale carp and Indonesian yellow carp. Despite the small size of the selected populations, the selection pressures for the first five generations in an average were severity of selection 19.8%, intensity of selection 1.52 and selection differential 93g. The realized heritability (h2) of body weight determined for carp of one of the three stocks was 0.29 in the first generation, 0.02 in the second generation, but this index declined to around 0 in the fourth generation. The total genetic gain for body weight of selected common carp after five generations was 33%. Thus, it was recommended to move to family selection in the next phase (1996-2000) of breeding program however its results were unexpected due to very low realized heritability of almost 0.1 in second selected generation. Continuing third phase breeding program of common carp is also presented in these report which is undergoing at National Broodstocks Center, RIA1 by croosbreed between 6 carp populations in prospect to gain genetic variation from improved carp lines and pure carp lines. Background According to the estimation of the Ministry of Fisheries (MOFI), the total fish production of the country in 1998 was 1.67 million tonnes, of which around 538,000 tonnes came from aquaculture (MOFI, 1998), providing nearly 35 % of the total animal protein intake of the nation. The main cultured fish species in Vietnam are local and exotic carps including common carp (Cyprinus carpio L), silver carp (Hypophthalmichthys harmandi and H. molitrix), bighead carp (Aristichthys nobilis), mud carp (Cirihina molitorella),
2 grass carp (Ctenopharyngodon idella), black carp (Mylopharyngodon piceus), rohu (Labeo rohita), mrigal (Cirrhinus mrigala), silver barb (Puntius gonionotus) and some some species of Clarias, Pangasius and Tilapia (Oreochromis niloticus). Aquaculture in Vietnam is facing with some problems, in the first instance should be indicate the deterioration of economically important traits, decreased growth rate, small maturation size, low survival and low disease resistance. Obviously, improvement of genetic quality of cultured fish species is one of the most essential approaches to increase aquaculture production. Common carp is a traditional and important cultured species in Vietnam. Among eight varieties of Vietnamese common carp white carp has been cultivated largely in many areas of the Country (Trong, 1983). However, white carp like other local varieties exhibited slow growth rate and early maturation. In 1970 and 1975 the mirror and scale strains of Hungarian common carp were introduced to Vietnam. Indonesian yellow carp was introduced to the South, Vietnam before 1975 and then transferred to the North in 1978. In the 70s the experiments on hybridization of the Vietnamese white carp with the Hungarian carps have been carried out (Tuong and Thien, 1979; Thien and Tuong, 1983; Thien, 1993). Hybrid carp (F1) showed fast growth and high survival. The best productivity was obtained from raising hybrid carp. However, due to importer breeding management, the base stocks of common carp in almost hatcheries over the country were gradually losing their purity, thus decreasing the effectiveness of commercial crossing for hybrids. Since 1981, research programs have focused on selection of common carp with the intention of creating a fish breed with stable genetic qualities. In the first phase (1981- 1985) the program focused on the assessment of initial materials for selection. In the second phase (1986-1995) mass individual selection has been carried out among the hybrid stocks over six generations. Continued family selection were carried out over 2 generations in the period of 1996 to 2000. Description of issue or practice The materials for selection were preliminarily selected among 8 local and 5 exotic varieties of common carp. They were Vietnamese white carp (V), Hungarian scale carp (H) and Indonesian yellow carp (Y). To bring together a number of positive qualities from these varieties and to improve the genetic variability of the initial materials for selection, at first three stocks of single hybrids were obtained by crossing Vietnamese carp with Hungarian carp (VH), Vietnamese carp with yellow carp (VY) and Hungarian carp with yellow carp (HY). Then the males of each single hybrid are crossed with
3 females of the third variety. The double hybrids obtained in these crossings have been evaluated and used as materials for further selection (Fig. 1). Assessment of initial materials for selection was made by comparing some morphological, physiological and biochemical characteristics among the above mentioned pure common carp varieties and their hybrids. In order to carry out mass individual selection about 5-10 families (one family included 1 female and 3-4 males) of each stock were bred at the same day. Their eggs were incubated under the same conditions. The rearing of fry and fingerlings and culturing them to marketable size were done under similar environmental conditions. On an average, about 20% of total number marketable fish in each stock were selected based on the body weight and appearance (big body and small head). The selection effectiveness was estimated according to Falconer (1960). R= Sh2 = iδh2 R: effectiveness of selection i: intensive of selection δ: average square variation S: selection differential 2 h : heritability of the trait (body weight) To estimate the coefficient of realized heritability of fish body weight in each selected generation, the experiments were implemented according to the schema in figure 2. Before mass selection of marketable fish was done, a randomly collected control population was kept. Then another group was collected by selecting for big body weight (experimental group). Deduction of the average body weight between experimental group and control group was a selection differential (S). In the next year the offsprings of the two groups were obtained by the same method and the fingerlings of control experimental groups were reared by communal stocking in the same pond to a marketable size. The deduction of the average body weight between two offspring groups had to be the effectiveness of selection for one generation (R). The heritability was calculated according to formula: R p1 –p0 H=-------------- = ------------------ S P1-Po
4 Vietnamese (white) Hungarian (scale) (Indonesian) Yellow Common carp Common carp Common carp V H Y F1 (Single) HY VY VH Χ V x Ξ (HY) Χ H x Ξ (VY) Χ Y x Ξ (VH) F1 V(HY) H(VY) Y(VH) (Double) 1986 M A S S L E L E C T I O N F2 1988 V(HY) H(VY) Y(VH) M A S S L E L E C T I O N F3 1989 V(HY) H(VY) Y(VH) M A S S L E L E C T I O N F4 1991 V(HY) H(VY) Y(VH) M A S S L E L E C T I O N F5 1993 V(HY) H(VY) Y(VH) M A S S L E L E C T I O N F6 1995 V(HY) H(VY) Y(VH) Fig. 1- Mass selection of Hybrid Common carp
5 Research and development Morphological characterization of common carp varieties and their hybrids There are 8 local and 3 introduced varieties of common carp in Vietnam. The local varieties, identified on basic of morphology and coloration, are white scaled, Bac Can, Ho Tay, South Hai Van, Red, Violet, High Body Depth and Scattered Scale varieties (Trong, 1983). The introduced common carps are Hungarian scaled, Hungarian mirror and Indonesian yellow varieties. Crossing between Hungarian carp and Vietnamese carp, Hungarian carp and Indonesian carp, Vietnamese carp and Indonesian carp was carried out in the 1980’s for investigation of their hybrid growth performance. Morphological study on Vietnamese, Hungarian, Indonesian and hybrid common carps (Table 1) was also conducted by Research Institutes for Aquaculture No.1 and the University of Hanoi in the same period (Thien and Tuong, 1983; Thien 1990). Table 1. Morphology and morphometrics of common carp varieties and their hybrids (H = Hungarian; Y = Indonesian Yellow; V = Vietnamese White). Descriptions Varieties Hybrids H Y V HxV HxY VxY 24.3 ± 1.41 22.2 ± 1.27 16.3 ± 0.61 21.2 ± 0.91 22.8± 1.21 12.9 ± 0.89 Body weight (g) 8.2 ± 0.16 ± 0.18 7.9 ± 0.09 8.1± 0.11 8.2 ± 0.15 6.9 ± 0.15 Standard length (Cm) 8.3 As % of standard length: 38.1 ± 0.19 35.1 ± 0.32 30.9 ± 0.25 35.5 ± 0.25 37.3± 0.28 32.2 ± 0.30 Maximal body height 14.3 ± 0.13 13.0 ± 0.13 11.9 ± 0.10 14.5 ± 0.16 13.9± 0.17 14.4 ± 0.17 Minimal body height 34.1 ± 0.24 31.9 ± 0.13 31.6 ± 0.16 34.4 ± 0.38 33.1± 0.30 32.1 ± 0.40 Length of head 36.3 ± 0.24 36.6 ± 0.25 33.5 ± 0.16 36.6 ± 0.38 34.4± 0.14 37.1 ± 0.30 Dorsal spine to tip most dorsal ray (DSR) 174.0 ± 1.6 185.7± 1.8 145.0 ± 1.3 175 ± 1.4 186 ±2.2 165.8 ± 2.1 Intestine length As % of head length: 26.6 ± 0.32 24.0 ± 0.37 29.6 ± 0.49 25.9 ± 0.45 25.4± 0.3 27.9 ± 0.50 Diameter of eye 17.8 ± 0.29 18.6 ± 0.25 18.0 ± 0.21 19.2 ± 0.21 18.2± 0.26 17.4 ± 0.30 Length of barbell
6 37.7 ± 0.20 32.9 ± 0.25 32.0 ± 0.14 32.6 ± 0.12 33.8± 0.16 33.4 ± 0.15 No. of lateral line scales 18.9 ± 0.12 18.3 ± 0.16 20.4 ± 0.16 18.0 ± 0.08 18.2± 0.26 19.0 ± 0.15 No. of Dorsal rays No. of Anal rays 5 5 5 5 5 5 24.9 ± 0.20 19.7 ± 0.17 20.7 ± 0.18 20.2 ± 0.20 22.7± 0.23 20.2 ± 0.18 No. of branched stamens in first bow 35.8 ± 0.12 35.1 ± 0.08 34.1 ± 0.08 34.4 ± 0.13 35.0± 0.16 34.7 ± 0.20 No. of vertebrae Genetic characterization of common carp populations Transferrin of pure common carp varieties and their hybrids was analysed using 12 % starch gel electrophoresis. Four banding patterns were observed, designated as A,B,C and D, with 8 different phenotypes (Thien and Tuong, 1983: Thien 1990) (Table 2). Table 2. Distribution (%) of Transferrin phenotypes in different common carp varieties (HS = Hungarian scaled; HM = Hungarian mirror; Y = Indonesian yellow; V = Vietnamese white; HS x V = hybrid Hungarian x Vietnamese). Carp n AA AB AC BB BC BD CC DD varieties HS 58 1.72 - 74.14 1.72 13.8 5.17 1.72 1.72 HM 9 11.1 88.9 - - - - - - Y 33 3.58 9.1 39.39 12.12 27.27 - 12.12 - V 28 3.02 - 92.84 - 3.58 - - - HS x V 33 - - 93.96 - - 3.02 - - Two banding patterns of serum esterase were obtained, designated as F (fast) and S (slow). There were three esterase phenotypes in pure varieties and their hybrids (Table 3). Two banding patterns with two phenotypes of pre-albumin were observed in pure and hybrid common carp varieties (Table 4). Serum proteins were also analysed in these strains and the H x V crossbred (Table 5). Table 3. Distribution (%) of esterase phenotypes in different common carp varieties (HS = Hungarian scaled; HM = Hungarian mirror; Y = Indonesian yellow; V = Vietnamese white; HxV = hybrid Hungarian x Vietnamese). Carp varieties N FF FS SS HS 58 81.03 18.97 -
7 HM 9 100.0 - - Y 33 - 100 - V 28 28.58 71.42 - HxV 33 42.42 42.42 3.03 Table 4. Distribution (%) of pre-albumin phenotypes in different common carp varieties (HS = Hungarian scaled; HM = Hungarian mirror; Y = Indonesian yellow; V = Vietnamese white; HxV = hybrid Hungarian x Vietnamese). Carp varieties N FS SS HS 58 8.64 91.36 HM 9 - 100.0 Y 33 12.12 87.88 V 28 3.58 96.42 HxV 33 9.09 90.91 Table 5. Serum protein of various common carp varieties (HS = Hungarian scaled; HM = Hungarian mirror; Y = Indonesian yellow; V = Vietnamese white; H x V = hybrid Hungarian x Vietnamese). α-globulin β-globulin δ-globulin (%) Varieties Total protein Albumin (g%) (g%) (g%) (g%) 2.60 ± 0.041 0.85 ± 0.034 0.63 ± 0.036 0.56 ± 0.036 0.56 ± 0.041 V 3.03 ± 0.044 1.05 ± 0.066 0.69 ± 0.029 0.63 ± 0.029 0.66 ± 0.04 HS 3.06 ± 0.033 1.06 ± 0.072 0.70 ± 0.025 0.68 ± 0.036 0.62 ± 0.033 HM 3.51 ± 0.033 1.18 ± 0.048 0.84 ± 0.039 0.75 ± 0.033 0.74 ± 0.033 Y 2.84 ± 0.022 0.90 ± 0.034 0.71 ± 0.026 0.64 ± 0.022 0.59 ± 0.022 HxV Heterosis in intraspecific crossbreeds of common carp Eight varieties of local common carp were investigated, of which white carp, a variety with high viability is the most popular (Trong 1983). However, this carp and other varieties of Vietnamese common carp presented slow growth and early maturity. Attempts aimed at obtaining heterosis by crossing among these varieties were not successful.
8 Two Hungarian common carp strains (mirror and scale carps) were introduced in Vietnam in 1970 and 1975 respectively. Under Vietnamese conditions, the Hungarian carps showed fast growth and late maturation but were easily infected with diseases and possessed low viability. The first hybrid generation (F1) crossing between Vietnamese white carp and Hungarian carp showed the best characteristics from their parents i.e. high survival rate, fast growth and attractive appearance. The survival rate of hybrid fry and fingerling was much higher than that of Hungarian carp (Table 6). At the same time survival rate of the hybrids and Vietnamese carp was similar. Table 6. Survival rate (%) of fry and fingerling of Vietnamese common carp (V), Hungarian common carp and their reciprocal hybrids (VH, HV). Stage Crossing Survival rate (%) 1974 1975 1976 V 51.6 - 71.2 Fry VH 61.6 70.0 80.0 HV 60.4 44.3 78.0 H 22.3 40.0 37.6 85.9 ± 9.4 78.3 ± 0.2 V - 94.9 ± 1.9 76.2 ± 2.9 90.0 ± 3.3 Fingerling VH 81.4 ± 7.5 76.7 ± 2.3 73.0 ± 11.3 HV 45.7 ± 5.2 38.6 ± 2.4 46.3 ± 5.1 H Mass selection of common carp The data collected during process of mass selection showed that the number of experimental fish in each stock was limited due to a limited number of ponds. Even though the scale of selection is small (Table 8) the indices obtained proved to be acceptable. Thus in first generation the number of fish obtained for mass selection in one of stocks was 1720, in each of two other stocks was 400 where as in second generation the number of fish in each stock was only 250 but the selection differential in second generation was even higher than that in F1. In the F3 generation field trials, due to poaching of some stocked fishes the total number of fish obtained for selection was reduced. So around 33% of fishes in each stock was selected. It led to declining of the selection intensity and the selection differential. In the next generations following the recommendation of some
9 geneticist-selectionists (Kirpichnikov, 1987) about 20% of fishes was kept to established the broodstocks. As a result the selection indices were stabilized in an acceptable level. After five selected generations the common carps of all three stocks have been clearly improved in growth rate and appearance. However, in order to estimate the genetic gain it was necessary to know the coefficient of heritability. The data obtained in the experiments to determining the realized heritability of body weight showed that the indices in the first two generations were suitable for individual selection, but they were decreased from F1 to F4 generation. In F1 generation the realized heritability was 0.29. In F2 generation experiments, the results were analyzed and adjusted according to the methodology of Wohlfath and Moav (1972), because of the difference in body weight between two groups of fingerling when stocked (Table 9). The realized heritability of body weight was 0.20 for the F2 generation. In the F4 generation this index was declined even to around 0. In fact, the effectiveness of individual selection of common carp in the last two generations was low. The experiment of comparison of growth rate of carps obtained from breeders in F3 and F5 selected generation (Table 10) showed that the difference in body weight was 7% only. It is expected that improvement of selection effectiveness in the next phase of the breeding program should be done by applying another method, for example, family selection. An average coefficient of realized heritability calculated for each generation was 0.16. So, based on average index of selection differential, the response to selection for increasing body weight in each generation could be estimated and it should be around 15g or 6.6%. So, the total genetic gain for body weight in the common carp breeding program after 5 selected generations was 33%. Decrease of the genetic gain could be caused by inbreeding. To avoid the inbred depression it was recommended to cross among the three stocks to producing hybrid seed for grow-out farmers. Preliminary data obtained in the experiments following this direction (Table 11) showed that the heterosis effect has found out in both experiments but it was more significant in the experiment No.2. Decline of realized heritability in these selection program might be caused by reducing in variability of selected trait. With intention of understanding the genetic structure of the selected common carp stocks in 5th generation, some isozymes namely Lactat dehydrogenase (LDH), Malat dehydrogenase (MDH), Aspartat aminotransferase (AAT) and Esterase (EST) located in blood, heart, liver and muscle of the fishes were studied by electrophoresis in 6% polyacrylamide gel. All the above mentioned isozymes were
10 polymorphic and the electrophoregrams included from 2 to 6 bands. The data on comparison of three stocks showed that LDH in muscle, heart and liver, MDH in liver and muscle, as well as AAT in blood, heart and muscle of the carps in all the stocks were identical. The electrophoretic patterns of AAT in liver, EST in heart and muscle were also similar but there were some differences between the stocks in frequency of the bands. Identification of the fish stocks could be done only by using parallel analysis of LDH, MDH and EST in blood. For the fishes in each stocks the identity of above mentioned isozymes was in very high level. Thus, genetic variability of the fishes within the stocks after 4-5 generations has been possibly declined. Table 7. Presentative data of the mass individual selection of the hybrid stocks of common carp (V-Vietnamese, H-Hungarian and Y-Indonesian Yellow common carp) Year Stocks Total Body Indices collected through selection generation No. of weight Severity Intensity i Differenti (S/δ ) and place fish (g) V (%) al S (g) 1986 H x (YxV) 400 162±6 12.5 2.77 99 F1 V x (YxH) 400 178±4 12.5 1.66 84 RIA.1 Y x (HxV) 1720 187±8 7.5 1.94 82 1988 H x (YxV) 248 152±7 10.1 1.76 117 F2 V x (YxH) 258 104±5 9.7 2.03 177 RIA.1 Y x (HxV) 253 148±9 9.9 1.60 164 1989 H x (YxV) 75 149±8 33.3 1.25 52 F3 V x (YxH) 243 155±12 32.9 0.80 62 RIA.1 Y x (HxV) 74 310±16 33.8 0.77 41 1991 H x (YxV) 200 260±6 20.0 1.26 74 F4 V x (YxH) 209 197±5 19.1 1.75 124 RIA.1 Y x (HxV) 189 299±6 25.9 1.24 47 1992 H x (YxV) 229 314±12 21.8 1.28 97 F5 V x (YxH) 235 300±9 21.3 1.72 69 RIA.1 Y x (HxV) 175 350±10 22.0 1.72 93 1993 H x (YxV) 257 226±10 19.5 1.39 85 F5 V x (YxH) 263 300±14 20.9 1.06 101
11 RIA.1 Y x (HxV) 243 318±11 22.6 1.44 114 1995 all stocks Brooders F6 Average for 5 generations 228 19.8 1.52 93 Table 8. Heritability (h2) of the body weight of hybrid common carp Hungarian x (Vietnamese x Yellow) Generation Parent's body weight (g) Offspring's body weight (g) Heritability h2=R/S Control Selected Control Selected Stock Stock Stock Stock F1 162±6 261±9 180±4 209±6 + 0.29 F2 218±10 312±21 316 335 + 0.20 1 246±5 334±9 264 268 +0.05 F4 2 246±5 334±9 288±7 282±5 -0.07 Table 9. Adjusted average body weight of the common carp in the experiment on determination of realized heritability in 1988 Group of fish Stocking weight (g) Harvesting weight (g) Weight after adjustment (g) Experiment 71±4 365±9 335 Control 51±3 286±9 316 Table 10. Growth rate of common carp of the F3 and F5 selected generations in a grow- out pond; Stock [Hungarian x (Vietnamese x Yellow)]-Communal stocking - 1995 Generation 6 July 18 Aug. 5 Oct. 16 Nov. 14 Dec. 9 Feb. 1996 1995 1995 1995 1995 1995 Stocking average average average average weight weight weight weight weight Average % (g) (g) (g) (g) (g) (g) F5 15.7 60 170±4 264±7 317±6 409±10 107 F3 15.7 60 170±8 232±7 305±9 382±9 100
12 Table 11. Body weight of common carp in pure stocks and their hybrids reared in the same pond, 1995 No. Stocks and Stocking Harvesting Heterosis effect Experiment their hybrids weight (g) weight (g) g % H x (VY) 20 365±10 + 21 5.8 1 Y x (HV) 20 377±10 +9 2.4 Hybrid 19 386±12 H x (VY) 16 367±12 + 127 34.6 2 Y x (HV) 17 415±10 + 79 19.0 Hybrid 17 494±15 Family selection of common carp Family selection of common carp has been conducted at RIA-1 since 1998, with the main objective to select a common carp line with fast growth and high survival to improve its production in aquaculture. Using the 5 th generation of common carp from mass selection as the initial materials, the programme has succeeded in producing two new generations through induced breeding and rearing of juvenile in hapas. The first generation, with about 375 brood fish, were selected from the 5 best families (out of 24). Following up the breeding workplan for the second generation, induced breeding was undertaken successfully with 40 families of the selected generation and 23 pairs of the base population. Rearing of juveniles has been carried out entirely in hapas. After harvest, 2000 fingerlings of the second generation were reared to marketable size for further selection. In the middle of 2001, fish in the growout pond were harvested for estimation of genetic parameters. Based on breeding value (A), 400 fish (200 females and 200 males) were selected as brood stock for the third generation of selection. Family selection of common carp has been conducted for three years (1998-2000). Following up the selection plan, the programme has succeeded in selection of the first generation and from then the second generation have been produced. Selection of individuals and families in the second generation was undertaken when the size of fish in growout ponds reached marketable size. In order to assess the result of selection after two selected generations, the realized heritability of body weight (h2) at the second selected generation need to be determined.
13 It is ensured that the h2 index can be computed until the present experiment fish in growout ponds reached around 1,000 g. However, it was considered that further family selection of common carp at RIA-1 depends on genetic gain. If the realized heritability (in second generation) was over 0.1, the selection programme could be continued. These index indicated over 5 % of faster growth of fish obtained in each selected generation. Combination of family and individual selection of common carp Six common carp (Cyprinus carpio L.) lines using as materials in these breeding program are 2nd generation of family selection (1), Hungarian 6th generation of mass selection (2), Yellow 6th generation of mass selection (3), Vietamese 6th generation of mass selection (4), Hungarian scale carp (5), Indonesian yellow carp (6). The broodfish was 2-3 years old with mean body weight of 1.5-3.0kg. All the spawners were healthy, free from disease and deformity. In Mach and early April 2004, full maturity of brooders were selected for production of families through artificial spawning. The brood fish were injected twice doses of hormone (LRH-a) in an interval of 5 hrs. After the second injection about 8-10 hrs. releasing of eggs started and stripping was done immediately for each family. Fertilization of eggs was followed by dry method. After washing adhesive, the eggs of each family were incubated separately in the jars of 10L volume. At 18.5-20oC of water temperature, hatching took place after 48-50 hrs. Due to limited facilities and un- consolidate maturation of brooder, 101 families were produced in 3 batches of which 12, 38, 51 families were in 1st, 2nd and 3rd respectively with 22 days longest distant between 1st and 3nd batch. All male and female spawners produced 101 families were marked by PIT tags (AVID Microchip) to identify the individuals and family number. After hatching, the larvae were gathered in the fine mesh size hapas for nursing. Within 3 days, the larvae completed yolk absorption; swim-up fry were fed with artificial food for 2 days before they were transferred to the rearing facility. Rearing of swim-up fry to the size of 0.5-1.0g was conducted in hapas. Swim-up fry of each family were stocked in 1 m3 hapas with the stocking density was 1,000fry/hapa. The fry were fed daily with the pelleted feed containing 40% crude protein at a rate of 10% body weight. Rearing period was 2 months (April-May). Fingerlings of each family were reared in 5.0 m3 hapas, 500 fry stocked in a hapa. The fry were fed daily with pelleted feed (30% crude protein) at 7% body weight. Rearing period lasted from May to June.
14 It was known that common carp could not growth well in hapas condition because of its habitat so experiment designed to culture in pond by position tagging using Code Wide Tag (CWT). Application of CWT for fingerlings could stock 5 families in the same pond when it marks 5 different position on tail, abdomance, back, left and right chick. The growout stage for marked CWT fish were conducted in earthen pond by devided into units of 120m2 area for each of 500 individuals for 5 families. Fish had grown in pond from June to August and reached 100-150g. At those time, some families were loss because of low survival rate. Other families were removed when fish appeared variety morphology as yellow color, no scale which are not prefered by consumer in Vietnam. Position marked families were screened by CWT scaner. In primary, the breeding experiment designed to produce 101 families by crossdreed between 6 lines of common carp available at National Broodstock Center of Northern Vietnam. As result, there have been 86 families available for Pit Tag application of 35fish/families. More than 3000fish have been injected Pit Tag and stocked communally in 2 ponds at the density of 1 fish per 1m2 from August up to now. Average fish weight is almost 350g/fish in recently. Figure 2. Crossbreeding between carp lines to produce 86 families Maternal parent Paternal Family Hungarian Hungaria Yellow Indonesia Vietnamese 6th gener. n scale 6th gener. line 6th parent selection, n Yellow 2nd gener. H(VY) carp Y(VH) gener. mass selection Family selection, 8 9 7 5 1 3 2nd gener. Hungarian 6th gener. 9 7 4 1 2 H(VY) Hungarian scale carp 6 4 4 - Yellow 6th gener. 5 3 3 Y(VH) Indonesian Yellow 3 3 Vietnamese line 6th 2 gener. mass selection
15 - Plan to collect data and analysis in June 2005 + Body weight was measured by using electronic balance with 0.01 g sensitive + Regression analysis was used to determined the correlation between survival and growth rate of fish in rearing stage + One way ANOVA was used to determine growth difference between families. + Means for individual final weight was compared using Least Significant Differences (LSD). Differences at P
16 References Dan, N.C., Thien, T.M., Tu, H.D., 2000. Family Selection of Common Carp (Cyprinus carpio L.) in Northern Vietnam. Paper is presented at the “Final meeting of Genetic Improvement of Carp Species in Asia” held in Wuxi, China. Falconer, D.S., 1960. Introduction to quantitative genetics. Edinburgh-London, 365p. Kirpichnikov, V.S., 1987. Genetics and selection of fishes. Leningrad, 520p (in Russian). Thien, T.M. and Tuong, P.M., 1983. Commercial hybridization of some pond fishes in Vietnam. In: Biotechnology in Freshwater Fish Culture. Hanoi, pp. 7-30 (in Vietnamese). Thien, T.M., 1993. A review of the fish breeding research and practices in Vietnam. In: Selective Breeding of Fishes in Asia and the United States-Proceedings of a Workshop in Hololulu. Hawaii, May 3-7. Thien, T.M., 1996. Carp breeding in Vietnam 1980-1996. Final Scientific Report, 15p. Trong, T.D., 1993. Research on variability of morphology of common carp (Cyprinus carpio L) in Vietnam. PhD thesis. Hanoi, 38p (in Vietnamese). Tuong, P.M. and Thien, T.M., 1979. Commercial Hybridization of common carp. Hanoi, 70p (in Vietnamese). Wohlfarth, G. and Moav, R., 1972. The regression of weight gain on initial weight in carp. Aquaculture No.1, pp.7-28.