首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
Triploidy could reduce breeding activity in tilapia without the use of hormones. In this study, the effect of triploidy on survival, growth, and gender of a line of red hybrid tilapia (Oreochromis mossambicus X Oreochromis niloticus) was assessed relative to the performance of diploid siblings. Triploidy was induced by preventing second polar body extrusion by applying either heat or cold shock. Growth was similar for both ploidies during the first 90 days of culture. However, at the age of 120 days, the average body weight of triploids produced by heat shock (215.5 ± 3.61 g) was significantly higher than that of cold shock (192.7 ± 2.6 g) and the diploid control (191.9 ± 1.74 g). Survival among triploids was inferior to diploids. Percentage of males in the triploid population was 82.9% in the heat-shocked treatment group, 54.8% in the cold-shock treatment, and 50% in the diploid control. Maximum attainable weight of red tilapia was calculated by applying the Ford-Walford growth plot: 650 g (heat-shocked triploids), 490 g (cold-shocked triploids), and 440 g in the diploid control.  相似文献   

2.
ABSTRACT:   To evaluate the aquaculture performance of triploid barfin flounder Verasper moseri , the sex ratio, maturation, growth and the relative proportion of body parts were examined. The sex ratio of triploids was similar to diploids under communal rearing conditions, but the proportion of female diploids was higher than that of triploids under separate rearing conditions. The gonadosomatic index of triploid females was very low even during the spawning season, and the ovaries were rudimentary. These results suggest that triploid barfin flounder females were sterile. In addition, triploid males produced a small quantity of milt containing very few spermatozoa with abnormal shapes. Spermatozoa obtained from triploids were aneuploidies. When normal eggs were fertilized with sperm from triploid males, no fry developed. These results suggest that triploid barfin flounder males were functionally sterile. Triploid males grew more slowly than diploid males, and triploid females showed similar or slower growth than diploid females, whether reared separately (23 months) or communally (35 months). The ratios of visceral weight to the edible parts for triploid males were similar to those for diploid males, but ratios for triploid females were higher than for diploid females during the spawning period. In conclusion, a significant improvement of growth was not found in triploid barfin flounders.  相似文献   

3.
Triploid rainbow trout exhibit improved survival and extended growth during sexual maturation, compared to their diploid counterparts. However, there have been few benefits demonstrated prior to sexual maturation. This study was undertaken to investigate the possibility of improving growth and survival parameters in triploids through interstrain crosses. Triploids were induced by heat shocking fertilized eggs from intra- and interstrain crosses of two rainbow trout strains. The four triploid groups and their diploid counterpart groups were reared to 233 days post-hatching and analyzed for growth and survival characteristics. Compared with diploids, triploids had significantly (P < 0.05) higher mortalities during the first 100 days post-fertilization, primarily just prior to and after hatching. However, during the remainder of the study triploids exhibited significantly (P < 0.05) lower mortalities than diploids. During the first 50 days of rearing all four triploid groups were significantly shorter and lighter than their diploid counterparts. The growth of the triploid groups later in the study varied considerably. At the conclusion of the rearing phase, one interstrain triploid group was significantly (P < 0.05) longer than its diploid counterpart, although not significantly heavier. The other triploid groups were either significantly smaller than, or equal to the diploids. Analysis of variance indicated that the growth of triploid rainbow trout was significantly affected by maternal strain effects. These results suggest that the use of specific strains and crosses may improve the growth of triploid rainbow trout.  相似文献   

4.
三倍体大黄鱼的诱导及其对生长、性腺发育的影响   总被引：1，自引：3，他引：1  
林琪 《水产学报》2004,28(6):728-732
自20世纪50年代以来,采用染色体操作技术人工诱导多倍体在鱼类遗传育种领域已得到广泛的应用。国内外已先后在三棘刺鱼[1]、鲤[2]、水晶彩鲫[3]等30多种鱼类成功获得三倍体。在理论上,由于三倍体性腺发育受阻,其用于性腺发育的能量可全部用于生长。因此鱼类育种学家期望通过诱导三倍体,使经济鱼类生长更快,经济效益更高。但历经30余年的研究,诸家看法仍未统一。一些学者认为三倍体鱼比二倍体生长快[4,5],另一些学者则认为三倍体鱼并不比二倍体生长快[6,7]还有一些学者的研究表明三倍体鱼在性成熟以后比二倍体生长稍快[8,9]。对于三倍体…  相似文献   

5.
Meiotic gynogenetic and triploid sea bass were produced by pressure shocks according to a previously published protocol. Pressure-treated groups did not survive as well as controls during early development and larval rearing. Performances, sexual maturation and carcass quality were examined over a period of 34–45 months. At the age of 34 months, growth of the gynogenetic fish was comparable to that of the control but inferior in the triploid fish. A predominance of male fish was found within the triploid groups, while diploid and meiotic gynogenetic fish showed equal proportions of the sexes. Gonadal maturation in triploid fish was significantly impaired, particularly in the females that showed rudimentary ovaries. Triploid males exhibited primary maturation but proved to be gametically sterile. Pressure-induced triploids did not grow as well as diploids, but these results might be ascribed to specific on-growing conditions (communal rearing). The performance of gynogenetic sea bass was comparable to that of control. The superiority of diploid fish over their triploid counterparts was confirmed during the final growing period and more clearly so in females. Performances of triploids varied according to their maternal origin. Overall, striking qualitative differences between diploid and triploid fish were found at the age of 34 and 45 months, although the results varied in a gender-specific manner. A strong maternal effect was also observed. The potential advantages of triploid sea bass for aquaculture purposes are discussed.  相似文献   

6.
Growth, skeletal structure and muscle composition of cold‐shock‐induced triploid olive flounder Paralichthys olivaceus were investigated. The average values of total length and total weight of triploids were higher than those of diploids from 5 to 11 months posthatch (mph). The growth difference disappeared after 11 mph. The skeletal structure of flounder at 11 mph was observed by X‐ray imaging method. There are four kinds of vertebral deformity including vertebrae fusion, one‐sided compression, two‐sided compression and vertically shifted. The trunk region (V8–18) and tailing end of the vertebral column were the predominant locations of deformity. In general, the frequencies of vertebral deformities in triploids (60.0%) were higher than those in diploids (33.3%, p < 0.05). Both the number of fish with deformed vertebrae and the average frequencies of deformed vertebrae in triploids were significantly higher than those in diploids (p < 0.05). The muscle tissues of diploid and triploid flounder at 11 mph contain the same types of fatty acid and free amino acid profiles. The number of fatty acids with significant higher contents in diploids and triploids was one and ten, respectively (p < 0.05). The contents of free amino acids showed no difference between triploid and diploid fish.  相似文献   

7.
Triploidy was induced in the bay scallop, Argopecten irradians, by treating newly fertilized eggs with cytochalasin B. Treatment for 20 min duration 10 min after fertilization resulted in 66% triploidy of scallops in the 0.05 mg/l cytochalasin treatment group and 94% triploidy of scallops in the 0.1 mg/l cytochalasin treatment group, detected by measuring the relative DNA content of scallop granulocytes using flow cytometry. Individually labelled scallops of known ploidy were grown in the Damariscotta River estuary in south-central Maine, U.S.A. from May 24 to September 15, 1982. Mean adductor muscle weight in triploid scallops was 73% greater than that of diploid controls and mean total body tissue wet weight was 36% greater. Shell inflation was significantly greater in triploids, while shell height and length were unaffected. The indexes of weight and glycogen content of the adductor muscle were significantly greater in triploids at the end of the growing season. The majority of triploid scallops failed to ripen during the summer months, while diploid scallops ripened and spawned.  相似文献   

8.
Two types of triploid hard clams Mercenaria mercenaria were produced by inhibiting polar body I (PB1) or polar body II (PB2) with cytochalasin B. Treatments were applied at 22–23°C, with PB1 inhibition starting at 4–7 min postfertilization and ending when PB2 was first observed in control groups, and with PB2 inhibition starting at 17–23 min postfertilization and ending when 80% of control eggs released PB2. Triploid induction success was evaluated by chromosome counting in 2–4 cell embryos and by flow cytometry at larval and juvenile stages. PB2 inhibition produced more triploids (82%–100%) than PB1 inhibition (71%–83%), although the difference was not significant (p ≥ .088). Triploid percentages in PB1‐ or PB2‐inhibited groups showed a small but insignificant decline during the first 6 months. At month 3, PB1 and PB2 triploids were not different from their within‐group diploids, but significantly larger than control diploids; PB1 triploids were significantly larger than PB2 triploids (p ≤ .003). At month 6, PB1 triploids were not different from either within‐group or control‐group diploids, while PB2 triploids were significant larger than both within‐group and control diploid; PB1 triploids were smaller than PB2 triploids. At month 16, PB1 and PB2 triploids in one remaining replicate were not different from their within‐group diploids. Overall, this study shows that triploids can be efficiently produced by PB1 or PB2 inhibition, and their growth performance relative to diploids is variable depending on age and replicates or parental genotype.  相似文献   

9.
Induction of triploidy and tetraploidy was attempted in Heteropneustes fossilis using heat shock. The optimal age of zygote, temperature level and duration of thermal shock required for effective induction of triploidy and tetraploidy was investigated in a series of experiments. A maximum of 82±7% triploids (3n=87) were obtained when fertilized eggs (2.5‐min old) were heat shocked at 40°C for 4‐min duration. A maximum of 40±8% tetraploids (4n=116) was obtained when the fertilized eggs (30‐min old) were heat shocked at 40°C for 4‐min duration. The triploid and tetraploid red blood cells (RBCs) nucleus volumes were 1.4 and 2.1 times greater, respectively, than that of the diploid RBC nucleus.  相似文献   

10.
In a 2-year grow-out trial, triploid Sydney rock oysters, Saccostrea commercialis (Iredale & Roughley), from two initial size grades grew faster (in terms of both mean whole weight and shell height) than the equivalent initial size grades of sibling diploids (P < 0.05). Small size grade triploids caught up with and had significantly heavier (P < 0.05) final whole weights than large size grade diploids after a 2-years grow-out period. The initial size grade had a significant effect on final mean whole weight and shell height for both ploidy types. After the 2-years grow-out trial, the final mean whole weights (but not shell heights) of small and large diploids (35.8 ± 0.6 g and 39.4 ± 0.5 g, respectively) were significantly different (P < 0.05). Small and large triploids grew at a similar rate for the first 18 months despite the significantly (P < 0.05) heavier final mean weight of large grade triploids (48.4 ± 0.8 g and 61.2 ± 0.7 g, respectively). The effect of the initial size grade on subsequent growth of both diploid and triploid oysters which was demonstrated in the present study is of significant commercial value to hatchery and nursery operators as well as growers of single seed oysters. In addition, small-grade triploids appeared to be more valuable in terms of potential growth rate than all diploid grades. There was no significant difference in the final percentage triploidy between small and large grade triploids. A large proportion of diploid/triploid mosaicism was detected in adult oysters.  相似文献   

11.
Induction of triploidy has been suggested as an effective tool to prevent spawning of farmed fish. This experiment examined the growth potential of triploid cod when reared communally with diploid ones after the juvenile stage. Pressure treatment was used to induce triploidy in a batch of cod eggs in April 2009. The resulting offspring were reared separately from their diploid counterparts until they reached the proper size for PIT tagging. At the age of 8 months, an equal number of 115 diploids (135.5 ± 3.95 g) and triploids (93.6 ± 2.63 g) were communally reared in a circular flow-through tank until the age of 22 months. By the end of this rearing period, diploids (1,002.4 ± 39.9 g) were significantly heavier than triploids (654.6 ± 27.7 g), but the specific growth rate did not differ significantly during the growth trial. Gonadal development at the age of 22 months was also lower among triploids than diploids, especially for females (5.3 and 91.9 %) but also for males (32.5 and 72.7 %). Sterility among female triploids was evident by the reduced size and dysfunctional gonads, but gonadal development in male triploids was less suppressed. Prevalence of body deformities was, however, significantly higher among triploids (62.6 %) than diploids (33.9 %). Higher prevalence of deformities in triploid cod underlines the need for further fine-tuning of the triploidization procedure or finding other methods of sterilization. At present, triploid cod are still far from being established as an alternative for commercial production.  相似文献   

12.
Wild caught Asian catfish were spawned manually following HCG injection, and a portion of the eggs were subjected to cold-shock at 4 C for 15 min within 2-min post-fertilization. Nuclear diameter measurements of cold-shocked fish revealed that 96% were triploids (3N), while non-shocked fish were all diploids (2N). During larval and fry culture (first 26 d), triploid fish mortality was =50%, while diploid mortality was =25%. Following 8-mo culture in tanks at three stocking densities, triploid fish survival was significantly greater ( P < 0.05), than diploids, with 84.0% and 57.3%, respectively. Triploid live weight was also significantly greater than diploids, with 69.2 and 45.9 g averages, respectively. Ninety-two percent of diploids had welldeveloped gonads after 8 mo; whereas none of the triploids had mature gonads. Gonads were undifferentiated with 31% of the triploids. These sexually undifferentiated fish had greater growth rates than male or female triploids, and greater growth than all diploids. Carcass weight (gutted) of triploids was 95.8% of live weight, compared with 92.5% for diploids. Lastly, triploids had very few deformities compared with diploids, with 1.3% and 17.6%, respectively. Deformities included curved spines, and humped backs just posterior of the head.  相似文献   

13.
Abstract. Triploidy was induced in the fighting fish, Betta splendens Regan, by varying all possible combinations of temperature (37-41°C), time after insemination (2-3min)and shock duration (2-4 min). Heat shock at 39°C for 3 min duration initiated 2-5 min after insemination gave high frequencies of triploids (86%) as assessed from chromosome number and red blood cell nuclear volume. There was no significant difference in the growth rate of triploid and diploid fish. Gonadal development in both sexes was retarded in triploids at 5 months of age. Eggs fertilized with milt from triploids developed to gastrulation. Beyond gastrulation there was increasing mortality associated with abnormalities and none of them hatched. The display frequencies of air gulping, erection of operculum and fins, striking and biting, and undulating movements were fewer in triploids compared to diploids. It appears that triploids are less aggressive than diploids. The aggressive behaviour of fighting fish may be related Io their reproductive activity.  相似文献   

14.
Large yellow croaker, Pseudosciaena crocea, exhibit sexually dimorphic growth, with females growing faster and reaching larger adult sizes than males. Thus, development of techniques for preferentially producing females is necessary to optimize production of these species. We have established a protocol to produce all-female croaker P. crocea through induction of meiotic gynogenesis with homologous sperm. The first set of experiments investigated the ultra-violet (UV) irradiation on sperm motility and duration of sperm activity to determine the optimal UV dosage for genetic inactivation of sperm, yet retaining adequate motility for activation of eggs. Milt from several males was diluted 1:100 with Ringer’s solution and UV irradiated with doses ranging from 0–150 J cm−2. The results indicated that motility and duration of activity generally decreased with increased UV doses. At UV doses greater than 105 J cm−2, after fertilization, motility was <10% and fertilization rates were significantly lower. Highest hatching rate was obtained at 75 J cm−2. A second set of experiments was carried out to determine appropriate conditions of cold shock for retention of the 2nd polar body in P. crocea eggs after fertilization with UV-inactivated sperm by altering the timing, temperature and duration of shock. At 20°C, shock applied at 3 min after fertilization resulted in higher survival rate of larvae at 6 h after hatching. Results of different combinations of three shock temperatures (2°C, 3°C or 4°C) and five shock durations (4 min, 8 min, 12 min, 16 min or 20 min) at 3 min after fertilization demonstrated that shocks of 12 min gave highest production of diploid gynogens. Statistical analysis revealed that maximum production of diploid gynogens (44.55 ± 2.99%) were obtained at 3°C. The results of this study indicate that the use of UV-irradiated homologous sperm for activation of P. crocea eggs and cold shock for polar body retention is an effective method for producing gynogenetic offspring.  相似文献   

15.
Triploidy was induced in mud loach (Misgurnus mizolepis) by cold shocking fertilized eggs 5 min post-fertilization at 2°C for 15 to 60 min. Best results were obtained when eggs were shocked for 60 min; 98% of fish examined in that treatment were triploids. Triploidy was confirmed by erythrocyte measurements and chromosome counts. Diploids had 48 chromosomes, while triploids had 72. Histological analysis of 9-month-old triploid ovaries showed an appreciable number of oocytes at the chromatin nucleolus stage with considerable interstitial tissue. However, diploids had well developed oocytes. Diploid testes from diploid males exhibited normal spermatids and spermatozoa, while a few were seen in triploid males. Growth rate was evaluated over a 9-month growth trial. Although male and female triploids were slightly heavier than their diploid counterparts from the third to the ninth month, their growth rates were not significantly different compared to their diploid controls.  相似文献   

16.
This study has investigated the muscle growth of diploid and triploid Atlantic cod (Gadus morhua) juveniles raised in replicate tanks over a period of 29 weeks and analysed at three sampling points (February, June and September). Data for weight, length, condition factor (K), muscle fibre growth and myogenic progenitor cells (MPCs) number were collected and results were analysed in relation to body growth and ploidy status. Diploids were significantly heavier than triploids throughout the trial (~10–20%) and had K in June and September samplings. Over the whole period, the rate of muscle fibres' recruitment was 318 fibres per day and 252 fibres per day for diploid and triploid cod respectively. The larger body weight of diploids resulted in a total number of fast fibre number of 114 979 compared to 91 086 in triploids. The average diameter of the 2.5% of the smallest fibres (2.5th percentile) was higher in diploids than triploids at the start of the trial, with a reversed picture for the average of the upper 2.5% (97.5th percentile) at the end of the trial. The probability density function of the estimated muscle fibre diameters showed similar fibre size distribution between size‐matched diploids and triploids at all sample points. The peak fibre diameter was approximately 25 μm in February and increased to approximately 50 μm in June and September, irrespectively of ploidy. Pax 7 were used as molecular markers for MPCs. A positive correlation between Pax 7+ cells and total body length was observed only among triploid fish at the onset of the experiment.  相似文献   

17.
The covariation between diploid and triploid progenies from common breeders was investigated in various progeny-testing experiments where either dams or sires were sampled from rainbow trout, Oncorhynchus mykiss (Walbaum), stocks. Triploidiza tion was found to frequently reduce the performance in the traits studied: body length and weight, growth, coefficient of condition and pyloric caeca number. Triploidization also generated significant interactions with the parental breeding value. These interactions were caused in part by the familial variance not being the same in triploids as in diploids, but also by actual ranking differences between diploid and triploid familial performances. However, the effect of these interactions was minor as compared with the amount of variation common to both ploidy levels (genetic correlations averaged 0.7–0.9). Therefore, selection of diploid breeders appeared efficient enough for improving triploid progeny, unless family selection methods including triploid progeny testing were preferred for other reasons. Lastly, it was observed that variances from maternal origin tended to be larger in triploids, whereas variances from paternal origin tended to be smaller, as compared with diploids. This point was discussed referring to the genetic make-up of triploids and in the scope of dams and sires for selective breeding.  相似文献   

18.
The performance (growth and survival) of diploid and triploid jundia, Rhamdia quelen, was evaluated at six different stocking densities (10, 60, 110, 160, 210, 260 larvae/liter) during 31 days after rearing in an intensive larviculture system. Triploid fish exhibited a significantly higher survival rate than diploids at all stocking densities (27.1 ± 4.3% vs. 12.1 ± 3.3%; P < 0.01). Survival was not affected by stocking density (P > 0.05). Length gain was not affected by either ploidy or stocking density. Diploid fish gained more weight than triploids (P < 0.05), though this difference could result from lower fish densities in diploid treatments resulting from the higher mortality rate of diploid fish. This hypothesis is strengthened by the higher biomass present in triploid treatments (P < 0.01).  相似文献   

19.
The triploid chromosome condition was induced in Thai silver barb (Puntius gonionotus) by application of cold shock (2°C) to eggs at time intervals after activation of 0.5 min with a duration of 10 min which resulted in mean triploidy yield of 72.5% at 9 months of age. Growth rate of the 2–9-month-old, cold shock group (0.1–6.2 g/month) did not differ from that of the control (0.1–5.7 g/month). Gonadal somatic indices (GSI) of presumed triploid males and females were lower than that of control (GSI values of the presumed triploids were 35.0–60.2% and 28.7–75.9% of control males and females, respectively). Spermatogenesis and oogenesis were retarded in triploids. However, all stages of spermatogenic cells were observed in triploid males, including few spermatozoa. Oocytes of triploid females did not undergo vitellogenesis while normal oogenesis was observed in diploids. Nuclear volume of red blood cells (RBCs) of triploid fish was 1.63 times larger than that of diploids.  相似文献   

20.
Triploidy as a result of thermal shock exposure of fertilized eggs decreases the growth rate ofOreochromis aureus as compared to their diploid controls, but this is due to the higher female ratio present in triploids (86%) and the lower growth rate of females. When females and males are considered separately, the growth rate is not significantly different in diploids and triploids. Since triploidy results in a malfunctioning steroidogenesis in females (mainly testosterone (T) and 17β-estradiol (E2)), but does not affect the growth rate, it is concluded that female gonadal steroids do not influence growth unless in pharmacological concentrations. These low levels of gonadal steroids are generally accompanied by higher levels of gonadotropin (GtH), but the difference is not always significant. Despite their lower growth rate diploid females have higher plasma concentrations of growth hormone (GH) during several months compared to the triploid females and diploid males. 3,5,3′-triiodo-L-thyronine (T3) levels, however, are comparable between diploid and triploid females (except for 1 month), but higher in diploid males in 4 of the 5 months studied. 11-ketotestosterone (11kT) is always higher in males. These results indicate that the higher growth rate of males may be related to the high circulating levels of T3 and 11kT.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号