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

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 (h 2 ) 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 70 s 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= Sh 2 = iδh 2 R: effectiveness of selection i: intensive of selection S: selection differential δ: average square variation h 2 : 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) Common carp Hungarian (scale) Common carp (Indonesian) Yellow Common carp H V Y HY V Y V H Χ V x Ξ (HY) Χ H x Ξ (VY) Χ Y x Ξ (VH) V( HY ) H (V Y ) Y (V H ) F1 (Double) 1986 MASS LELECTION V( HY ) H (V Y ) Y (V H ) F2 1988 MASS LELECTION V( HY ) H (V Y ) Y (V H ) F3 1989 MASS LELECTION V( HY ) H (V Y ) Y (V H ) F4 1991 MASS LELECTION V( HY ) H (V Y ) Y (V H ) F5 1993 MASS LELECTION V( HY ) H (V Y ) Y (V H ) F6 1995 F1 (Single) 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). Varieties Hybrids Descriptions H Y V H x V H x Y V x Y Body weight (g) Standard length (Cm) 24.3 ± 1.41 8.2 ± 0.16 22.2 ± 1.27 8.3 ± 0.18 16.3 ± 0.61 7.9 ± 0.09 21.2 ± 0.91 8.1± 0.11 22.8± 1.21 8.2 ± 0.15 12.9 ± 0.89 6.9 ± 0.15 As % of standard length: Maximal body height Minimal body height Length of head Dorsal spine to tip most dorsal ray (DSR) Intestine length As % of head length: Diameter of eye Length of barbell 38.1 ± 0.19 14.3 ± 0.13 34.1 ± 0.24 36.3 ± 0.24 174.0 ± 1.6 26.6 ± 0.32 17.8 ± 0.29 35.1 ± 0.32 13.0 ± 0.13 31.9 ± 0.13 36.6 ± 0.25 185.7± 1.8 24.0 ± 0.37 18.6 ± 0.25 30.9 ± 0.25 11.9 ± 0.10 31.6 ± 0.16 33.5 ± 0.16 145.0 ± 1.3 29.6 ± 0.49 18.0 ± 0.21 35.5 ± 0.25 14.5 ± 0.16 34.4 ± 0.38 36.6 ± 0.38 175 ± 1.4 25.9 ± 0.45 19.2 ± 0.21 37.3± 0.28 13.9± 0.17 33.1± 0.30 34.4± 0.14 186 ±2.2 25.4± 0.3 18.2± 0.26 32.2 ± 0.30 14.4 ± 0.17 32.1 ± 0.40 37.1 ± 0.30 165.8 ± 2.1 27.9 ± 0.50 17.4 ± 0.30 6 No. of lateral line scales No. of Dorsal rays No. of Anal rays No. of branched stamens in first bow No. of vertebrae 37.7 ± 0.20 18.9 ± 0.12 5 24.9 ± 0.20 35.8 ± 0.12 32.9 ± 0.25 18.3 ± 0.16 5 19.7 ± 0.17 35.1 ± 0.08 32.0 ± 0.14 20.4 ± 0.16 5 20.7 ± 0.18 34.1 ± 0.08 32.6 ± 0.12 18.0 ± 0.08 5 20.2 ± 0.20 34.4 ± 0.13 33.8± 0.16 18.2± 0.26 5 22.7± 0.23 35.0± 0.16 33.4 ± 0.15 19.0 ± 0.15 5 20.2 ± 0.18 34.7 ± 0.20 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 varieties n AA AB AC BB BC BD CC DD HS HM Y V HS x V 58 9 33 28 33 1.72 11.1 3.58 3.02 - - 88.9 9.1 - - 74.14 - 39.39 92.84 93.96 1.72 - 12.12 - - 13.8 - 27.27 3.58 - 5.17 - - - 3.02 1.72 - 12.12 - - 1.72 - - - - 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 Y V H x V 9 33 28 33 100.0 - 28.58 42.42 - 100 71.42 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 HM Y V H x V 58 9 33 28 33 8.64 - 12.12 3.58 9.09 91.36 100.0 87.88 96.42 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). Varieties Total protein (g%) Albumin (g%) α-globulin (g%) β-globulin (g%) δ-globulin (%) V HS HM Y H x V 2.60 ± 0.041 3.03 ± 0.044 3.06 ± 0.033 3.51 ± 0.033 2.84 ± 0.022 0.85 ± 0.034 1.05 ± 0.066 1.06 ± 0.072 1.18 ± 0.048 0.90 ± 0.034 0.63 ± 0.036 0.69 ± 0.029 0.70 ± 0.025 0.84 ± 0.039 0.71 ± 0.026 0.56 ± 0.036 0.63 ± 0.029 0.68 ± 0.036 0.75 ± 0.033 0.64 ± 0.022 0.56 ± 0.041 0.66 ± 0.04 0.62 ± 0.033 0.74 ± 0.033 0.59 ± 0.022 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). Survival rate (%) Stage Crossing 1974 1975 1976 Fry V VH HV H 51.6 61.6 60.4 22.3 - 70.0 44.3 40.0 71.2 80.0 78.0 37.6 Fingerling V VH HV H 85.9 ± 9.4 94.9 ± 1.9 81.4 ± 7.5 45.7 ± 5.2 - 76.2 ± 2.9 76.7 ± 2.3 38.6 ± 2.4 78.3 ± 0.2 90.0 ± 3.3 73.0 ± 11.3 46.3 ± 5.1 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 5 th 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 and place No. of fish weight (g) Severity V (%) Intensity i (S/δ ) Differenti al S (g) 1986 F1 RIA.1 H x (YxV) V x (YxH) Y x (HxV) 400 400 1720 162±6 178±4 187±8 12.5 12.5 7.5 2.77 1.66 1.94 99 84 82 1988 F2 RIA.1 H x (YxV) V x (YxH) Y x (HxV) 248 258 253 152±7 104±5 148±9 10.1 9.7 9.9 1.76 2.03 1.60 117 177 164 1989 F3 RIA.1 H x (YxV) V x (YxH) Y x (HxV) 75 243 74 149±8 155±12 310±16 33.3 32.9 33.8 1.25 0.80 0.77 52 62 41 1991 F4 RIA.1 H x (YxV) V x (YxH) Y x (HxV) 200 209 189 260±6 197±5 299±6 20.0 19.1 25.9 1.26 1.75 1.24 74 124 47 1992 F5 RIA.1 H x (YxV) V x (YxH) Y x (HxV) 229 235 175 314±12 300±9 350±10 21.8 21.3 22.0 1.28 1.72 1.72 97 69 93 1993 F5 H x (YxV) V x (YxH) 257 263 226±10 300±14 19.5 20.9 1.39 1.06 85 101 [...]... 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... viability of juvenile and growth rate of adult fish - Selection of individuals Intensity of selection was 20% of the best individuals with sexual ratio (male: female) was 1:1 Conclusion 1 The long term breeding program of common carp has been carried out in Vietnam with the goal to increase growth rate and attractive appearance of the fish After generations of individual selection the body weight of marketable... 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 unconsolidate 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... Heritability of family selection has gradually reduced to very low (0.1) in second selected generation 3 To continue the breeding program in the next phase combination of family and individual selection is undergoing with very realizable genetic gain when using variety genetic materials of hybrid carp lines and pure carp lines 4 It is expected that the best way to disseminate improved common carp seed... 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. .. 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 growout pond; Stock [Hungarian x (Vietnamese x Yellow)]-Communal stocking - 1995 Generation 6... (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... 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... 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... 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 . 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. 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.). 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