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1.
To determine the genotype with better traits for aquaculture practices of the loach, factorial crosses were made among diploid (D), tetraploid (T) dojo loach, Misgurnus anguillicaudatus, and large‐scale loach, Paramisgurnus dabryanus (P), producing DD, DT, DP, TD, TT, TP, PD, PT, and PP genotypes (female listed first). The growth performance and survival of different genotypes in culture were evaluated through a 48‐wk rearing trail. The average fertilization rate in genotypes with P. dabryanus as female parental was significantly higher than those of M. anguillicaudatus as female parental. The average fertilization level of sperm from P. dabryanus was about the same as diploid M. anguillicaudatus but significantly higher than tetraploid M. anguillicaudatus. The highest survival rate was found in DD group (52.77%) and PP group (50.31%) (P > 0.05). The intergenetic crosses between P. dabryanus and M. anguillicaudatus, especially for PD (19.05%), DP (17.89%), and PT (15.44%) groups, exhibited poor survival rates. Under the similar rearing conditions, PP group showed significant growth advantage. Growth rates of the interspecific hybrid progenies were found to be intermediate in comparison with the parental species. According to these results, the PP genotype is more suitable for aquaculture practice .  相似文献   

2.
Abstract— Grow-out performance of striped bass Morone saxatilis , palmetto bass ( M. saxatilis ♀ × M. chrysops ♂ ) and backcross hybrids [sunshine bass ♀( M. chtysops ♀ × M. saxatilis ♂) × M. saxatilis ♂] was examined in a two-part study. During part I fish (mean weight = 20.1 g) were stocked at a density of 56 fish/m3 in 1.8-m3 cylindrical fiberglass tanks connected to a central biological filter. Fish were fed a 38% protein trout ration daily and the study duration was 273 d. At harvest, no differences ( P > 0.05) in mean weight or feed conversion were detected among the fish types. However, there were differences in specific growth, with the striped bass having a significantly higher growth rate than the palmetto bass and the backcross hybrids being intermediate. The condition factor (K) for striped bass was also significantly lower (1.2) than that recorded for either of the other two groups. In addition, survival of striped bass (91%) was significantly higher than that of backcross hybrids (74%), while survival of palmetto bass (87%) was intermediate. The survival of backcross hybrids was adversely impacted by an infestation of the dinoflagellate Amyloodinium sp . During part II stocking density in each tank was reduced to 19 fish/m3. The study lasted 104 d. At harvest, no differences were detected in weight, survival, or feed conversion. However, there were significant differences in specific growth, length and K. Striped bass and backcross hybrids gained weight faster than palmetto bass. Length and K were inversely related with all groups being significantly different. Striped bass had the largest TL and the lowest K while, palmetto bass were the shortest with the highest K.  相似文献   

3.
三角帆蚌三个优异群体杂交后代生长性能比较研究   总被引：7，自引：0，他引：7  
于2003年5月21日至2004年12月23日,在浙江诸暨的养殖池塘比较研究了三角帆蚌(Hyriopsis cum-ingii)的洞庭湖群体(DD)、鄱阳湖群体(PP)和太湖群体(TT)自交F1与其6个杂交F1(DP,PD,DT,TD,TP和PT)的生长性能。结果显示:19月龄的9个群体三角帆蚌壳长已趋于相对恒定,但早期各群体间壳长差异明显。壳宽性状从6月龄至19月龄,PP、PD和TD三者均无明显差异,但均优于其余6群体(P<0.01)。特别发现PD从4月龄至19月龄均呈现明显的生长优势。从整个试验阶段来看,PD的体重也具有生长优势;经572 d生长发育,生长最快的依次为PD((0.42±0.07)g/d)、TD((0.37±0.04)g/d)和PP((0.37±0.08)g/d),生长最慢的是TT((0.30±0.08)g/d)、DP((0.32±0.06)g/d)和PT((0.32±0.07)g/d)。各性状的杂种优势率在-1.95%～17.08%之间。对于壳宽性状,PD、TD和PT均产生了杂种优势,且以PD最大,达到7.99%。在体重性状上,PD的杂种优势最大,达到了17.08%,其次为TD(14.10%),因此,PD与TD的养殖性能最好。  相似文献   

4.
Experimental crossings were made between tetraploid loach (Misgurnus anguillicaudatus, T for short) and diploid large‐scale loach (Paramisgurnus dabryanus, P for short), resulting in T×T, T×P and P×P crosses (female before male). Meanwhile, a part of T×P cross was cold shocked to inhibit second meiosis (T×P‐0 for short). Fertility rate, hatching rate and survival rate of T×T, T×P, P×P and T×P‐0 were measured. Flow cytometry and chromosome count were taken to identify ploidy statuses of the four crosses. Results showed that T×T, T×P and P×P were, respectively, tetraploidy (4n = 100), triploidy (3n = 74) and diplody (2n = 48), while 89.19 per cent of T×P‐0 of 12 months old were pentaploidy (5n = 124, T×P‐0‐5n for short) and the others were triploidy. Morphological data of the four crosses of 12 months old showed that morphological characteristics of T×P and T×P‐0‐5n loach were between those of their parents, while T×P‐0‐5n loach presented a smallest head length/body length. Total lengths of T×P and T×P‐0‐5n were significantly larger than those of T×T and P×P, showing hybrid vigour. This study will provide valuable information for production of polyploidy loach and breeding programmes of the two loaches and other closely related species.  相似文献   

5.
Cross-breeding was investigated as a strategy to improve performance of the Australian native freshwater fish, silver perch ( Bidyanus bidyanus Mitchell) through the exploitation of heterosis during the fingerling phase of production. Growth, and mid and best parent heterosis of two wild strains, Cataract Dam (C♂× C♀) and Murray River (M♂× M♀) and their reciprocal crosses (C♂× M♀ and M♂× C♀) were evaluated in cages and ponds through summer, and in tanks in a re-circulating aquaculture system during winter. The M × C cross grew significantly faster than the reciprocal cross and pure strains in cages and tanks, had the lowest coefficients of variation of weight and length and was 20.9% and 16.0% heavier than mid-parent and best-parent average, respectively, when grown in ponds. Differences in growth between the reciprocal crosses were also evident, with C × M expressing significantly less heterosis in cages and tanks. Faster growth of M × C was attributed to greater appetite; however, at sizes approaching 250 g this feeding vigour diminished. The results of this study suggest that use of the M × C cross has the potential to reduce the length of the culture period and lower costs of silver perch production.  相似文献   

6.
Insulin‐like growth factor‐I (IGF‐I) participates in the modulation of the cellular development, differentiation and proliferation in various vertebrate tissues. Therefore, variations in IGF‐I gene are good candidates as growth regulators. In this study, a novel 79‐bp insertion/deletion (I/D) polymorphism was identified in 3′‐flanking region of IGF‐I gene by polymerase chain reaction (PCR) and sequencing approaches in common carp Cyprinus carpio. To gain insight into the association of the 79‐bp I/D polymorphism with growth‐related traits, a total of 747 individuals from Heilongjiang carp Cyprinus cario haematopterus (YL) (n = 263), selective line of German mirror carp Cyprinus carpio L. mirror (JL) (n = 229), and cold‐resistance line of Hebao red carp Cyprinus carpio var. wuyuanensis (HL) (n = 255) were genotyped. The DD genotype of the polymorphism was significantly associated with higher body length (135), body weight (325, 385, and 445 days), net weight (445 days) and lower overwintering body loss rate in JL. In addition, in pooled population (YL+JL+HL), fish with DD genotype also showed significantly higher body weight (445 days) and net weight (445 days) than those with II genotype. Taken together, these results suggest that the novel polymorphism in IGF‐I gene could be considered as a potential genetic marker for selection of growth performance in common carp.  相似文献   

7.
The present study was aimed at the identification of treatment optima to induce triploidy in ‘Labeo rohita (rohu) × Cirrhinus cirrhosus (mrigal)’ hybrid using heat shock treatment. The eggs were exposed at four different temperature regimes viz., 38, 39, 40 and 41°C for 1–3 min, applied 3–5 min after fertilization. After 4 min of fertilization, heat shock treatments for 1 and 1.5 min durations were found the best inducing triploidy up to 100% and 96% respectively. Survival rates upto yolk sac absorption were found to be 73% and 71% in rohu and mrigal, 68% and 67% in the reciprocal diploid hybrids and 61% and 60% in the reciprocal triploid hybrids (RTH). Triploidy was confirmed by chromosome counting that revealed the diploid chromosome number of rohu and mrigal at 2n = 50 and in their triploid hybrid chromosome number was found to be 3n = 75. Growth rate of the RTH showed a significant difference (P < 0.05) from the single species and the diploid hybrids. Triploids also showed higher survival rate over the diploids.  相似文献   

8.
Lengths and weights of Auburn University-Egypt and Auburn University-Ivory Coast strains of Tilapia nilotica and their F1 F2, and backcross hybrids were analyzed by multiple regression to estimate strain additive genetic effects, strain maternal genetic effects, individual heterosis (specific combining ability), maternal heterosis, and strain egg cytoplasmic effects for growth to determine why heterosis of the F2 and backcross hybrids was greater than that of the FI hybrids. Individual heterosis and maternal heterosis made the greatest contributions to growth. The F2 and backcross hybrids were larger than the F1 hybrids because of maternal heterosis. Regression coefficients were used to predict growth for any possible hybrid combination. Egypt ♀× Ivory Coast ♂ FI hybrid females backcrossed to Egypt males and Egypt ♀× Ivory Coast ♂ F2 hybrids were the largest groups evaluated in this study and were also predicted to have faster growth rates than any other possible Egypt-Ivory Coast hybrid.  相似文献   

9.
Oxygen consumption and ammonia excretion of black carp (Mylopharyngdon piceus Richardson) (4.6 ± 0.3 g) and allogynogenetic crucian carp (Carassius auratus gibelio ♀ × Cyprinus carpio ♂) (5.7 ± 0.5 g) were examined when fish fed two types of carbohydrate (dextrin and glucose) at two levels (20 and 40%) each. The diets were isonitrogenous (40% dry matter) and isocaloric at 18.5 kJ g−1 (dry matter) by adjusting the oil content to 10.1 and 1.5%, respectively. In black carp, the interactions between the carbohydrate type and level were found in oxygen consumption at 3 and 6 h and in ammonia excretion at 6 h after feeding. At 20% carbohydrate, no significant difference was observed between dextrin and glucose in oxygen consumption. However, at 40% carbohydrate, oxygen consumption in fish fed glucose was significantly higher than that in fish fed dextrin at 3 and 6 h after feeding. Within the dextrin diets, no significant differences in both oxygen consumption and ammonia excretion were detected between the two carbohydrate levels. Within the glucose diets, however, fish fed 40% glucose showed significantly higher oxygen consumption than those fed 20% glucose at 3 and 6 h after feeding. Ammonia excretion in black carp fed 40% glucose was higher than that in black carp fed 40% dextrin at 6 h and also found higher than those in the other three treatments at 24 h after feeding. The postprandial oxygen consumption and the ammonia excretion in crucian carp fed 40% glucose were the highest, but no significant differences were observed. Our data indicate that the escalation of glucose to 40% in a fish diet results in high oxygen consumption and ammonia excretion in black carp, suggesting that the efficiency of glucose as an energy source for this fish is compromised by the high metabolic expenditure after feeding. Crucian carp, on the other hand, have a better ability to cope with dietary carbohydrates.  相似文献   

10.
Effects of rhythmic temperature change on the growth, body composition and energy budget of hybrid grouper (Epinephelus lanceolatus ♂ × E. fuscoguttatus ♀) were investigated. Nine groups of fish received repeating cycles of low‐temperature manipulation (22°C) for 1, 2 and 4 days followed by recovery temperature (28°C) for (3, 7 and 11 days), (6, 14 and 22 days) and (12, 28 and 44 days) respectively, designated as L1R3, L1R7, L1R11, L2R6, L2R14, L2R22, L4R12, L4R28 and L4R44 respectively. In the control group (C), fish were reared at 28°C throughout the whole experiment. After 96‐day feeding trail, the final weight, relative weight gain rate, specific growth rate, food conversion efficiency and apparent digestibility coefficient of fish in L4R28 were significantly higher than those of control (p < .05). The crude protein contents of fish in L2R14, L2R22, L4R12, L4R28 and L4R44 were significantly higher compared to the control (p < .05). According to energy budget, fish in L4R28 exhibited significantly higher proportion of food energy assimilated into growth and lower proportion consumed for excretion than the control fish (p < .05). These results indicated the occurrence of complete or over growth compensation in hybrid grouper, and the use of repeated cycles of low temperature (22°C) for 4 days followed by recovery temperature (28°C) for 28 days could obtain enhanced growth, that is overcompensation, with improved apparent digestibility coefficient, food conversion efficiency and energetic efficiency into growth. This technique would be more practically applicable in indoor culture for this species.  相似文献   

11.
Interspecific allo-tetraploidy was induced by a combination of hybridization of Megalobrama amblycephala ♀× Megalobrama terminalis ♂ and thermal shock. A thermal shock at 40 °C for 2 min applied to eggs 33 or 26 min (τ0: 1.40) after fertilization resulted in a significantly ( P <0.01) higher yield of allo-tetraploids than hybrid crosses without heat shock. The yield of allo-tetraploids in embryos from mid-gastrula to hatching stages was 15.7–24.4% in different thermal shock treatment groups. The allo-tetraploidy rate in 330-day-old juveniles was 9.3% and 6.7% in different year treatment groups. After 2 years of rearing, allo-tetraploidy males attained sexual maturity with milk-like milt at the age of 2+, while allo-tetraploidy females at the age of 2+, and even at 3+, did not show any signs of sexual maturation exhibiting obviously delayed maturity. Only a few allo-tetraploidy females (three individuals) showed maturation characters at the age of 4+ and these females were induced to spawn.  相似文献   

12.
The age and growth of two Nematalosa species around Okinawa Island were examined using sectioned otoliths collected from September 2003 to April 2006. Monthly changes in the frequency of the appearance of a translucent band on the outer margin of the otoliths indicated that ring formation occurred once a year from January to July for Nematalosa come and from January to March for Nematalosa japonica. The von Bertalanffy growth equations for both species were as follows: N. come: L t  = 365.5{1 − exp[−0.111 × (t + 0.288)]} for females and L t  = 214.7{1 − exp[−0.700 × (t – 1.110)]} for males; N. japonica: L t  = 205.1{1 − exp[−1.068 × (t − 1.180)]} for females and L t  = 195.5 {1 − exp[−1.293 × (t − 1.269)]} for males. The maximum ages observed for N. come and N. japonica were 11 and 6 years old, respectively. The growth of these species was characterized by the slow growth of N. come over many years, resulting in a larger size than N. japonica.  相似文献   

13.
Positive and negative interploid triploids of blunt snout bream (Megalobrama amblycephala) were produced by reciprocal crossing autotetraploids with diploids. Fertilization and hatching rate of negative interploid triploid, 2n♀× 4n♂, at different reproductive ages was similar to that of control, but higher than that of positive interploid triploid, 4n♀× 2n♂. Additionally, the development rate of embryos of the positive interploid triploid, 4n♀× 2n♂, was slower than that of control and the negative interploid triploid, 2n♀× 4n♂. Gonad growth of the positive and negative interploid 3n was significantly (P<0.01) affected by parents, and spawning could not be induced both in females and males at the 2+ age. The negative interploid 3n (2n♀× 4n♂) had a significantly higher survival rate than the positive interploid 3n (4n♀× 2n♂), but close to the level of the control (P<0.05). The daily growth rate of the negative interploid 3n was similar to that of the good breed ‘Pujiang No. 1’ blunt snout bream (2n) during the early life stages.  相似文献   

14.
In the present study, methodology of gynogenetic induction in spotted halibut were developed and optimized; the sex ratio of putative meiotic gynogenetic diploids was determined using AFLP-based molecular sexing technique; the homozygosity of gynogenetic population was assessed as opposed to cultivated population. The results showed that high percentage of meiotic gynogenetic diploids were generated when the eggs fertilized with irradiated heterologous sea perch frozen sperm (30–50 mJ cm−2) were cold shocked in sea water of −1°C for 40–75 min at 5 min after fertilization. About 15,200 diploid gynogenetic larvae were achieved and they exhibited normal morphology similar to diploid control. The gynogenetic diploids were 100% female, which first confirmed the female homogamete (XX/XY) sex determination in spotted halibut. The genetic analysis showed that the average H O was, respectively, 0.404 and 0.724 in gynogenetic population and cultivated population, indicating an increase of homozygosity in gynogenetic population.  相似文献   

15.
The purpose of this study was to investigate the growth and physiological status of Litopenaeus vannamei subjected to one constant temperature (25°C) and four cyclical temperature change regimes (25 ± 1°C, 25 ± 2°C, 25 ± 3°C and 25 ± 4°C). The growth rates of shrimp at 25 ± 2°C or 25 ± 3°C were significantly higher than that at a constant temperature of 25°C. On the other hand, the growth rate in 25 ± 4°C regime was significantly lower than those in other regimes. The daily feed intake rate of shrimp at 25 ± 4°C was the lowest, and the food conversion efficiency was also significantly lower than those at 25 ± 2°C and 25 ± 3°C, respectively. The food conversion efficiency at 25 ± 2°C or 25 ± 3°C was significantly higher than those in other regimes. Thus, it can be inferred that the growth enhancement in the test shrimp at the suitable diel fluctuating temperatures was due to high food conversion efficiency. Studies of the physiological parameters showed that at 25 ± 4°C, the hemolymph glucose content of the test shrimp was the lowest, while the activity of PK in hepatopancreas was the highest, which indicated that the test shrimp at 25 ± 4°C was in a stressed condition. The hemolymph glucose content of the test shrimp at 25 ± 3°C was the highest, and the activity of HK in hepatopancreas was the lowest. These results indicated that the test shrimps at 25 ± 3°C were not in a stressed condition. Compared with the constant temperature regime, the expression of HSP70 in any of the four cyclical temperature change regimes was not significantly increased. The reason for this might be that the fluctuation amplitude of ± 4°C did not induce the increased expression of HSP70.  相似文献   

16.
Bacillus subtilis isolated from the intestine of Cirrhinus mrigala (Hamilton) was incorporated into the rearing water of Poecilia reticulata (Peters), Poecilia sphenops (Valenciennes), Xiphophorus helleri (Heckel) and Xiphophorus maculatus (Gunther) at four different concentrations (5 × 108 cells ml−1, 5 × 107 cells ml−1, 5 × 106 cells ml−1 and 5 × 105 cells ml−1) and its effect on fish growth performance and survival, water quality parameters and bacterial population of water were assessed. The results showed that the addition of bacterial cells in the rearing water resulted in greater survival and a faster growth rate and, hence, greater length and weight increments of the livebearers. The use of a bioaugmentor in the rearing water of the livebearing fishes resulted in significantly lower (P < 0.05) concentrations of dissolved organic matter and total ammonium nitrogen. The counts of motile aeromonads and total coliforms recorded in the water of bioaugmented tanks were also lower than that in the control tank. Bioaugmentation between 106 and 108 cells ml−1 in the rearing water is sufficient in establishing a bioaugmentor and the use of a higher concentration of bacterial cells did not always lead to significantly better results.  相似文献   

17.
Herein, we developed a triploidization method using spawned eggs collected immediately after spawning of eastern little tuna (ELT), Euthynnus affinis. ELT broodstock induced the spawning by hormonal treatment in the tank, with the resulting spawned eggs being used for the triploidy induction. Under optimal conditions, the mean ± SEM triploidization and hatching rates were 97.2 ± 2.8% and 84.5 ± 10.3%, respectively. Although triploid ELT showed growth performance equivalent to that of diploids, the triploids died at a higher rate than the diploids during 2–4 weeks post‐hatching when triploids and diploids were reared in the same tank. Therefore, we propose that it would be necessary in a practical operation to use triploid‐only ELT seedlings to avoid selective cannibalism by the diploids. The ELT triploids exhibited an all‐female phenotype. Because previous studies have reported that female triploids show a greater probability of sterility than male triploids, this characteristic could be a major advantage. Since this triploidization method, using spawned eggs, can be performed without handling the broodstock, it is possible to avoid the physical damage caused by the process of artificial insemination, making it possible to repeatedly produce triploid populations without valuable broodstock loss. Thus, we have developed an efficient method to produce ELT triploids, although further study is essential to evaluate sterility of the triploid ELT.  相似文献   

18.
Sibling harvest age Black Tiger shrimp triploids and diploids of both sexes were reared to reproductive maturity, crossed with wild caught females and males, conditioned for spawning and a comprehensive reproductive performance trial was undertaken. Ovarian development, spawning frequency, fecundity, hatch rate, gonad morphology, male reproductive tracts and thelycum impregnation rates of the wild female × triploid male cross were assessed. After ablation, ovarian development and cycling between wild G0 diploid and G1 diploids was not significantly different, whereas G1 triploids failed to show any signs of ovarian development and cycling, thus resulting in no G1 triploid female spawnings. There were 10 G0 diploid female × G0 diploid male first‐spawnings and 9 G0 diploid female × G1 diploid male first‐spawnings, all of which produced viable nauplii. In comparison, there were 7 G0 diploid female × G1 triploid male first‐spawnings, none of which produced viable nauplii. The 26 wild G0 diploid female spawnings had more eggs than the 1 G1 diploid female spawning. Gonad morphology and male reproductive tract assessments showed impaired reproductive development in triploid gonadal tissues of both sexes (compared with sibling diploids and wild shrimp) to a point where complete maturation had not occurred. The thelycum of 16 wild G0 diploid females crossed with G1 triploid males had no visible spermatophore present, suggesting that G1 triploid males are incapable of developing viable spermatophores and mating with females. This study demonstrates that the triploid females and males are incapable of producing viable gametes and are thus reproductively sterile.  相似文献   

19.
There is increasing evidence for complex dosage effects on gene expression, enzyme activity and phenotype resulting from induced ploidy change. In this study, ocean-type chinook salmon were bred using a 2 × 2 factorial mating design to create four families and test whether triploidization resulted in changes in growth performance and smolting. Eggs were pressure shocked after fertilization to create triploid fish from a subset of each family. In June, fish were sampled for size, plasma insulin-like growth factor 1 (IGF-1), gill Na+–K+-ATPase activity, and expression of two Na+–K+-ATPase α subunits in the gill. Diploids were significantly heavier than triploids, and there were significant differences due to family. Despite a significant positive correlation between plasma IGF-1 and fish size, plasma IGF-1 did not differ between diploid and triploid smolts. Diploids also had significantly greater gill Na+–K+-ATPase enzyme activities than triploids and there was a strong family effect. Gill Na+–K+-ATPase α1b isoform expression differed significantly by family, but not ploidy, and generally families with lower Na+–K+-ATPase enzyme activity had higher α1b isoform gene expression. Na+–K+-ATPase α1a isoform expression did not differ among any of the groups. Although diploids were larger and had higher specific activities of Na+–K+-ATPase in the gills, there was no difference in gene expression or circulating hormone levels. The strong family effect, however, suggests that strain selection may be useful in improving performance of triploids for aquaculture.  相似文献   

20.
The utilization of plant‐based diets in fishes could be affected by their genetic backgrounds. To examine this, three strains of one‐year‐old gibel carp, Dongting (strain DT: 30.42 ± 0.05 g), CAS III (strain A: 43.34 ± 0.08 g) and CAS Ⅴ (strain F: 61.78 ± 0.10 g), were fed fishmeal (FM), soybean meal (SBM) and rapeseed meal (RM) diets for 8 weeks. The present results showed that growth performances, feed utilization, body composition, postprandial kinetics of plasma metabolites and gene expression of lipid metabolism markers in the three strains were affected by diets and strains (p < 0.05). Strain A had higher SGR than strain DT and F (A > F > DT) with the three diets, whereas strain F had higher FE than the other two strains with FM and RM diets (p < 0.05). Compared to FM diet, plant protein‐based diets resulted in poor growth, feed use and nutrient retention in all the three strains, and different strains showed differing changes in fatty acid synthesis and oxidation to different dietary proteins. Overall, strain A showed better growth performances than the other two strains irrespective of diet, and all the three strains could utilize RM diet better than SBM diet.  相似文献   

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