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1.
Over the past decade, viral pathogens have caused mass mortalities of farmed shrimp throughout the major shrimp farming regions of the world. In addition, the global shrimp farming industry has been criticized for negatively impacting coastal environments. These issues have raised concerns about the sustainability of traditional shrimp farming practices, and have prompted farmers and researchers to develop biosecure technologies that promote a sustainable industry. Current technologies include the use of specific pathogen free (SPF) shrimp that are grown to market size in recirculating systems that rely on pathogen exclusion. Inherent in this approach is the need to produce SPF broodstock under biosecure conditions. However, there is a paucity of information on broodstock growth and reproductive performance when they are reared in recirculating systems. The present investigation compares shrimp growth and reproductive performance in two trials where shrimp were cultured from market size (20 g) to broodstock size (40–60 g) in a recirculating aquaculture system (RAS) versus a flow-through earthen pond (EP). In trial 1, mean growth rates of males and females in the RAS were 0.83 and 1.33 g/week, respectively. In the EP, males and females grew 1.07 and 1.48 g/week, respectively. In trial 2, mean growth rates of males and females in the RAS were 0.90 and 1.53 g/week, respectively, whereas in the EP, males and females grew and 1.24 and 1.78 g/week. Slower growth rates in the RAS may be attributed to the lack of natural productivity, which provides supplemental nutrition to the shrimp. In addition to growth rates, reproductive performance of broodstock reared in the RAS was compared with historical reproductive performance of broodstock reared in the EP. Data on spawning success and production of viable nauplii revealed no significant differences (P>0.05) between broodstock shrimp reared in these two systems. These results indicate that broodstock shrimp can be cultured in a biosecure RAS while maintaining good growth and high survival. In addition, reproductive performance of broodstock shrimp reared in a RAS is not compromised when compared with broodstock shrimp reared in a conventional, flow-through pond.  相似文献   

2.
在盐度31、水温28~29℃下,进行了4次卵巢诱导试验,研究了切除单侧眼柄对体质量56.4~105.4g的养殖斑节对虾卵巢发育和产卵的影响及卵巢发育、产卵与体质量之间的关系。结果显示,切除单侧眼柄诱导养殖斑节对虾卵巢发育成熟,成功率(y)与雌虾体质量(x)显著相关(P0.05),雌虾体质量越小,诱导成功率越低,回归方程为:y=133.92lnx-535.63(r2=0.9297)。养殖斑节对虾眼柄手术后,最快10d产卵,部分雌虾能重复产卵。产卵量(y)与雌虾体质量(x)显著正相关(P0.05),雌虾体质量越小,产卵量越小,回归方程为:y=122.22lnx-472.2(r2=0.9738)。雌虾累积死亡率、卵子直径和卵子孵化率与雌虾体质量无显著相关性(P0.05)。建议用体质量80g以上的养殖斑节对虾雌虾作为亲虾。  相似文献   

3.
本研究对A、B两个凡纳滨对虾选育群体的亲虾形态特征及其产卵量和孵化率进行比较,结果表明A、B群体的体型性状存在一定差异,尤其是体重、体长、头胸甲长、第二腹节高和尾节长存在显著差异(P0.05),其他形态性状差异不显著(P0.05)。两个群体亲虾产卵量分别为(0.65±0.20)×104、(0.64±0.18)×104粒/体重(g),差异不显著(P0.05),但无节幼体量和孵化率差异显著(P0.05)。A群体产卵量与体型不显著相关(P0.05),亲虾产卵量(Y,×104粒)与体重(W,g)的回归方程:Y=0.010 3W1.0878(R2=0.410 3);B群体凡纳滨对虾亲虾体重与产卵量显著相关(P0.05),亲虾产卵量(Y,×104粒)与体重(W,g)的回归方程:Y=0.054 5W0.677 8(R2=0.522 8)。  相似文献   

4.
Abstract. Populations of postlarval, juvenile and adult Kuruma prawns, Penaeus japonicus Bate, have been affected by an unusual proliferative condition of the midgut and ventral nerve cord. Animals affected with this gut and nerve syndrome have been observed from various shrimp systems in Hawaii, including high density tanks and raceways, low density ponds, and adult broodstock held in a maturation system. Affected shrimp ranged in age from ∼20-day-old postlarvae of ∼0.02g average weight to adult shrimp of ∼ 60 g average weight. The principal lesions observed in affected animals were a hypertrophy of the anterior midgut mucosal epithelium basement membrane (BM) and a hyperplasia of the epineurium that covers the ventral nerve cord and segmental ganglia in the gnathothorax. There seemed to be a positive correlation between increased thickness of the BM and disease, and possibly a relationship between ataxia and lethargy and the degree of hyperplasia of the epineurium.  相似文献   

5.
The present study compares the relative costs of stocking ponds with postlarvae from wild or domesticated Kuruma shrimp, Penaeus japonicus (Bate), broodstock. Wild broodstock were obtained from a commercial trawler. Domesticated broodstock were reared to harvest size (wet weight = 25 g) on a commercial farm and then transferred to controlled environment tanks where they were grown to a final wet weight of 50 g. The costs of stocking ponds with postlarvae were calculated from the observed reproductive output, the costs of purchasing wild broodstock and the costs of domesticated broodstock production in the controlled environment facility. Domesticated P. japonicus spawned comparable numbers of eggs to wild broodstock of similar size, but hatching success was significantly lower. A total of 12 domesticated P. japonicus broodstock would be needed to produce the postlarvae to stock a 1-ha pond, compared to only six wild broodstock. However, the much higher relative costs of wild broodstock means that the cost of using their postlarvae would be Aus$851 per pond compared to Aus$390 for domesticated broodstock. The present authors conclude that the use of domesticated P. japonicus broodstock could be a cost-effective alternative to wild broodstock in Australia and in other countries where P. japonicus is farmed.  相似文献   

6.
Several male Penucus stylirostris were selected from a 3 ha commercial earthen pond and were individually evaluated for reproductive performance. Indicators measured were compound spermatophore weight, sperm count, and sperm abnormalities.
It was found that spermatophore quality was significantly better for 30–40 g shrimp than for 20–30 g shrimp ( P < 0.05). The higher frequency of abnormalities measured in younger males and the inverse relationship between abnormalities and sperm count indicate that the vas deferens could be the tissue responsible for producing highly abnormal immature semen. It is proposed that male maturation has at least three independently controlled levels of organization: testes maturation, vas deferens maturation, and spermatophore synthesis.
The individual evaluation showed that each male followed a particular response in reproductive quality. Changes in spermatophore weight were not an indicator of sperm density within spermatophores.
Male reproductive tract degenerative syndrome (MRTDS) and male reproductive system melanization (MRSM) did not develop in any shrimp during these experiments.  相似文献   

7.
The growth, survival and reproductive performance of domesticated Australian stocks of the giant tiger shrimp Penaeus monodon were evaluated in trials conducted in 1997 and 2003. The 1997 trials assessed the performance of first generation progeny of wild broodstock from the northeast coast of Australia and fourth generation progeny of pond‐reared broodstock, which also originated from northeast coast wild stocks. In these trials, growth and survival of the shrimp were assessed when reared for 17 mo in tanks. Reproductive performance of the shrimp was assessed at 14.5 mo and 17 mo. The 2003 trials assessed the performance of first generation progeny of wild broodstock from the Gulf of Carpentaria (north coast of Australia). In these trials, growth and survival of shrimp were assessed when reared for 14 mo in tanks and raceways. Reproductive performance of the shrimp was assessed at 11 mo, 12 mo, and 15 mo. Growth and reproductive performance of the stocks varied between trials, families, ages and rearing systems. The most pronounced differences in growth and reproductive performance were between the 1997 and 2003 trials. At 11 mo of age, the average wet weight of the shrimp in the 2003 trials (females 117.1 ± 5.8 g; males 87.9 ± 7.6 g) was 200% greater than the average wet weight of shrimp in the 1997 trials (females 55.2 ± 6.8 g; males 41.2 ± 3.4 g). The reproductive performance of the shrimp was also higher in the 2003 trials in terms of the percentage of spawnings hatching (52.0% in 1997; 77.1% in 2003) and mean hatch rate (21.5% in 1997; 31.6% in 2003). Differences in the growth and reproductive performance of the tank‐reared stocks between years were indicative of significant improvements in the rearing environment, diet and husbandry techniques. Variation in the reproductive performance between families was consistent across rearing environments and at different ages and suggests the potential to improve reproductive performance through genetic selection. Notably, this study identified hatch rates of nauplii from the spawned eggs as a key area for future improvement of domesticated stocks reared in tanks and raceways. Future efforts to improve the growth and reproductive performance of domesticated P. monodon could benefit from integrating incremental improvements to husbandry with genetic selection.  相似文献   

8.
Spermatophore and sperm quality of male Argentine red shrimp Pleoticus muelleri held under laboratory conditions was evaluated using compound spermatophore weight, sperm count and percentage of live sperm as indicators. Thirty-seven males of S to 20 g wet weight were held indoors in a 3-m diameter circular fiberglass tank for 45 d. They were fed fresh squid, clam and pelletized diet. Spermato-phores were obtained by manual ejaculations. Four shrimps were re-ejaculated to verify the subsequent spermatophore regeneration. Spermatophore mean weights were significantly lower for 5–10 g males than for 15–20 g males ( r = 0.998) (P < 0.05). There were no significant differences in sperm count and percent live sperm among the different weight classes (5–15 g, 15–20 g, 20–25 g). The sperm count varied from 2.22 to 5.62 million. No change in sperm quality was seen in re-ejaculated individuals. During the first 2 wk of the experiment, the spermatophores exhibited healthy morphology and colour; by the fifth week evidence of spermatophore deterioration was apparent. Despite the degree of melanization, sperm quality was not affected and the high variability in sperm count indicated that the artificial ejaculation is adequate in this species.  相似文献   

9.
肖广侠  孔杰  孟宪红  罗坤  栾生  曹宝祥  刘宁 《水产学报》2013,37(7):1009-1014
为评估中国明对虾生长及抗WSSV能力与中国明对虾WSSV携带量之间的相关性,实验对130个中国明对虾家系进行生长及抗WSSV性能测试,对收集到的中国明对虾生长和抗病数据,输入“水产动物育种分析与管理系统”数据库,利用综合选择指数法估计中国明对虾各个家系的育种值。根据分析结果,选择出生长育种值最大的5个家系和最小的5个家系、抗WSSV育种值最大的5个家系和最小的5个家系,分别检测上述20个家系的亲虾、养殖50 d及170 d中国明对虾的WSSV携带量。结果显示,亲虾、50 d中国明对虾及170 d中国明对虾的WSSV携带量分别为0.190 8、0.286 6和0.232 9 copies/ng DNA,三者之间差异均不显著。亲虾、50 d中国明对虾和170 d中国明对虾的WSSV携带量与中国明对虾的生长育种值相关系数分别为 0.021、0.363和0.185,亲虾、50 d中国明对虾和170 d中国明对虾的WSSV携带量与抗WSSV育种值相关系数分别为0.033、0.048和0.019。研究表明,中国明对虾的生长育种值和抗WSSV育种值与中国明对虾体内的WSSV携带量均无显著的相关性。  相似文献   

10.
The objective of this work was to study the relationship between female size (weight) and variables of egg and larval stage of Persian sturgeon Acipenser persicus . In this study, 19 female breeders were captured in Caspian Sea and fertilized by routine methods. Positive significant correlations ( P <0.05) were established between female weight and ovulated eggs per female, time of second mitosis division and volume of yolk-sac at hatching. There was not significant correlation ( r =0.33, P =0.161) between female weight and egg diameter. Female weight was not affected weight of larvae at hatching time ( r =0.37, P =0.119), as well as larval length ( r =−0.14, P =0.558) and larval weight at the end of the experiment (48 hours after first feeding) ( r =0.16, P =0.491). Mortality rate during yolk-sac absorption was higher with increased female weight but their correlation was not significant ( r =0.40, P =0.076). During the first feeding stage, mortality rate was 13.39% and there was no significant correlation between mortality rate in this period and female weight ( r =−0.12, P =0.613). Conclusively, as a result female size influenced fecundity, time of second mitosis division and yolk-sac volume at hatching time without affecting mortality rate during yolk-sac absorption and first feeding stage in Persian sturgeon. Thus, smaller female broods do not cause more mortality than larger ones in larval production and they can be used in reproduction procedure.  相似文献   

11.
A commercial red tilapia farm was diagnosed with Streptococcus agalactiae infection using histopathology, microbiology and immunohistochemistry. One hundred fish were randomly taken from different weight/age groups including broodstock, market fish (larger than 150 g), on-growing fish between 20 and 150 g, juveniles and larvae. Fish were clinically examined, anaesthetised and necropsied. Samples were taken from brain, liver, spleen, eyes and kidney for microbiology. All organs were processed for histopathology and an indirect immunoperoxidase test (IIP). Organs from wild fish and birds found in close proximity to the farm were also sampled for microbiology and IIP. The prevalence of lesions or infection found by IIP, histopathology and microbiology was 16%, 29% and 7% respectively. Clinical disease, lesions or infection were not seen in larvae or juveniles. By contrast, infection and disease were found in fish larger than 20 g, suggesting that the condition was linked to the intensive culture conditions of broodstock, on-growing and market fish. S. agalactiae was not found in wild fish, or in birds, by microbiology and IIP.  相似文献   

12.
Abstract

A feed manufacturing method involving the production of large pellets followed by crumbling to desired diet sizes was used to produce six shrimp diets to determine its effect on growth of three size classes of Pacific white shrimp, Litopenaeus vannamei. The six diets containing 45% protein were 0.7 mm crumble, 1.2 mm crumble, 1.7 mm crumble, 2.2 mm crumble, 2.6 mm crumble, and 3.0 mm pellet. These diets were fed to three size classes of shrimp subjected to a four-week growth trial under indoor laboratory conditions. Stocking density was 12 shrimp/aquarium for size class 1 (1.13iö.01 g), 9 shrimp/aquarium for size class 2 (7.31iö.06 g), and 6 shrimp/aquarium for size class 3 (13.12iö. 10 g). Shrimp were fed three times daily and were evaluated for live weight, growth rate, feed conversion ratio (FCR), and survival. Results for shrimp growth appeared to be affected by diet size and pellet water stability. The effects of diet size, however, were more evident on smaller sized shrimp. Weekly growth rates for class 1 and class 2 shrimp indicated significant responses (P < 0.05) to the effects of diet size, while the class 3 shrimp did not show any significant result. The growth rates for both class 1 and class 2 shrimp were lowest at the smallest diet size (0.7 mm crumble) but differed with respect to highest growth rates. The largest diet (3.0 mm pellets) yielded the highest growth rates for class 1 shrimp, while medium sized feed (2.2 mm crumble) produced the best growth for class 2 shrimp. This could be partly attributed to pellet water stability, which had a direct correlation to diet size (r = 0.97). Smaller diet sizes resulting from crumbling larger pellets tend to have lower water stability. The water stability decreased from 82.5% to 76.3% as the 3.0 mm pellets were reduced to 0.7 mm crumbles. Stress cracks are created during crumbling, and surface area to volume ratio are increased as larger particles are reduced to crumbles. These would make smaller diet particles more susceptible to disintegration and nutrient leaching. For class 3 shrimp, the largest pellets produced the highest growth rate. This high growth value, however, was not significantly different (P > 0.05) from growth results produced by the crumbled feed sizes. This observation suggests that diet sizes ranging from 0.7 mm crumble to 3.0 mm pellet could be used for a 13 g shrimp, although preference would be given to larger pellets due to higher growth performance and better pellet water stability. Results for shrimp live weights were similar to results obtained for weekly growth rates. FCR and survival of all shrimp sizes did not show any significant response from the effects of various diet sizes. However, larger shrimp were less efficient in their diet utilization than smaller shrimp.  相似文献   

13.
Dietary Effects on Sperm Quality of Litopenaeus vannamei Broodstock   总被引：1，自引：0，他引：1  
A 56‐d feeding trial was conducted to investigate the effect of diet on sperm quality of Pacific white shrimp Litopenaeus vannamei broodstock. Dietary treatments consisted of a combination of 75% dry maturation diet and 25% fresh‐frozen squid (dry‐weight basis). Supplemental nutrients of the maturation diet were selectively deleted and replaced with wheat starch to produce the following treatments: 1) 75% basal maturation diet plus 25% squid (control); 2) 75% maturation diet without supplemental vitamins plus 25% squid; 3) 75% maturation diet without supplemental cholesterol and phospholipids plus 25% squid; 4) 75% maturation diet without supplemental astaxanthin plus 25% squid; and 5) a fresh diet composed of 60% squid and 40% Maine bloodworms. Shrimp fed the control diet and the diet without supplemental astaxanthin had significantly higher mean (± SEM) change in sperm count (4.6 ± 3.2 million sperm cells and 2.9 ± 2.5 million sperm cells, respectively), with respect to baseline (8.7 ± 1.0, 6.4 ± 1.0, 9.0 ± 1.3, 6.6 ± 0.7, and 6.0 ± 0.8 million sperm cells for treatments 1, 2, 3, 4, and 5, respectively), than shrimp fed the diet without supplemental vitamins (‐1.7 ± 2.6 million sperm cells), but not significantly higher than those of shrimp receiving the diets without supplemental cholesterol‐phospholipids (1.2 ± 2.5 million sperm cells) and the fresh diet (1.3 ± 1.6 million sperm cells). Dietary deficiencies also were reflected in weight gain of shrimp fed the diet without supplemental vitamins (‐2.0 g) and the fresh diet (‐0.8 g). which were significantly lower than weight gain of shrimp fed the control diet (1.1 g) and the diet without supplemental cholesterol‐phospholipids (0.8 g). No significant differences were detected among treatments for percentage of abnormal sperm and survival data. Results demonstrated a significant effect of diet on reproductive quality of male L. vannamei and indicated that the typical combination of fresh‐food organisms used is not nutritionally optimal for male broodstock.  相似文献   

14.
The present study analyzes the reproductive performance of three size classes of wild (average weight of 46.5, 55.0, and 63.2 g) and three size classes of pond-reared (18.4, 21.3, and 25.1 g) Penaeus paulensis females. Unilaterally eyestalk ablated females were placed for 70 d in 3.6 m diameter tanks at 6 individuals/m2 and a 1.2:1 female-male ratio. Number of spawns, eggs, nauplii, fertilization and hatching rates were recorded every second day. The length of unfed protozoea I larvae was also recorded. Larger broodstock shrimp tended to suffer higher mortality rates. Smaller, pond-reared females started spawning at 28.2 ± 4.1 g. The number of eggs and nauplii per spawning event were not significantly different between experimental groups (P > 0.05), but due to their higher spawning frequency, small wild females (46.5 ± 3.7 g) outperformed medium (55.0 ± 1.8 g) and large ones (63.2 ± 7.0 g). No relationship between protozoea length and spawner size was found. Optimum size for the maturation of wild P. paulensis females was estimated to be from 30 to 60 g. It is suggested that the use of this size range can potentially enhance nauplii production of P. paulensis .  相似文献   

15.
Penaeid shrimp reared in eutrophic pond water grow significantly faster than shrimp in clear well water, and this growth enhancement is especially pronounced in postlarval shrimp. The objective of this study was to determine if the nutritional benefits of pond water could supplement a lower protein feed for postlarval Pacific white shrimp Litopenaeus vannamei . Sixteen 230-L tanks were stocked with 10-d postlarvae at a density of 350 shrimp/tank. Four treatments (four replicates/treatment) were tested for 6 wk and consisted of: 1) shrimp grown in well water and fed a commercially available 45%-protein feed (W/45); 2) shrimp grown in pond water and fed the same 45%-protein feed (P/45); 3) shrimp grown in well water and fed a commercially available 52%-protein feed (W/ 52); and 4) shrimp grown in pond water and fed the same 52%-protein feed (P/52). At the end of the experiment. mean weight gain (± SE) for shrimp in pond water (1.85 ± 0.03 g) was significantly greater ( P > 0.0001) than shrimp in well water (0.98 ± 0.10 g). Mean weight gain for shrimp fed the 52%-protein feed (1.56 ± 0.13 g) was significantly greater ( P > 0.0001) than shrimp fed the 45%-protein feed (1.26 ± 0.20 g). In addition, there was a significant interaction effect between water source and feed ( P > 0.0001). Mean weight gain for shrimp in the W/52 treatment (1.23 ± 0.04 g) was 68% greater than shrimp in the W/45 treatment (0.73 ± 0.03 g). However, mean weight gain for shrimp in the P/52 treatment (1.90 ± 0.03 g) was only 5% greater than shrimp in the P/45 treatment (1.80 ± 0.04 g). These results suggest that organically rich pond water provides postlarval shrimp with sufficient nutrients to compensate for nutritional deficiencies associated with a lower protein feed.  相似文献   

16.
The effect of feeding four semi‐purified diets A1, A2, A3, A4, containing different vitamin A acetate levels 0, 20, 40, 60 mg kg?1 diet, respectively, on fecundity, egg hatching rate, larval survival rate and vitamin A content in eggs of Chinese shrimp (Penaeus chinensis) broodstock was compared with a fresh clam diet (control) in a 60‐day feeding trial. The broodstock shrimp fed the diet with 60 mg kg?1 vitamin A acetate added exhibited significantly higher fecundity (P < 0.01). Hatching rate was highest with diet A4 (P < 0.05), whereas hatching rates were similar fed diets A1, A2, A3. Increasing levels of vitamin A in broodstock diet resulted in improvement in larval quality. The vitamin A levels in shrimp eggs from broodstock fed with diet A4 were higher compared with those from broodstock fed with diet A1, A2 (P < 0.01). The fecundity and hatching percentages were positively correlated with the vitamin A content in eggs in the present study. The results of this study showed that higher level of vitamin A in broodstock diet may have positive effects on fecundity and larval quality in P. chinensis.  相似文献   

17.
在基础饲料中添加灵芝与黄芪共发酵产物——灵芪菌质,探讨灵芪菌质对凡纳滨对虾生长性能及非特异性免疫指标的影响。试验选用平均体质量(0.51±0.03)g的凡纳滨对虾幼虾,随机分为5组,每组3个重复,每个重复30尾虾。采用单因子试验设计,在基础饲料中分别添加0%、0.5%、1.0%、1.5%、2.0%的灵芪菌质。试验虾在水温为22～30℃的循环玻璃纤维水槽中饲喂60d。试验结果表明,添加1%灵芪菌质组与对照组相比,对虾相对质量增加率提高了31.88%(P<0.05),饵料系数降低了14.37%(P<0.05),成活率提高了15.16%(P<0.05);对虾血清酚氧化酶活力和超氧化物歧化酶分别提高了99.94%(P<0.05)和26.79%(P<0.05)。添加1.5%灵芪菌质处理组与对照组相比,对虾酸性磷酸酶活力和碱性磷酸酶活力分别提高了128.44%(P<0.05)和111.55%(P<0.05),对凡纳滨对虾的副溶血弧菌攻毒免疫保护率高达73.34%(P<0.05)。本次试验,凡纳滨对虾溶菌活性与灵芪菌质添加量呈一定的正相关(y=1.802x+11.104,r2=0.9378,P<0.05)。添加灵芪菌质可显著提高凡纳滨对虾的生长性能,改善其非特异性免疫力。  相似文献   

18.
Allelic frequency differences at the highly polymorphic MI microsatellite of B20 locus were examined in Taura Syndrome Virus (TSV)-susceptible (Kona) and TSV-resistant (Select) lines of Pacific white shrimp Litopenaeus vannamei . DNA was screened from 1,009 cultured L. vannamei , 166 from the Kona line and 843 (97 broodstock and 746 offspring) from the Select line. A total of 34 different MI alleles were found, 41.2% of which were shared by the two lines, and 58.2% were unique to either line. Only seven (20.6%) of the 34 alleles had similar frequencies in the two lines. The most frequent (22.4%) allele in the Select line (218 bp) was absent from the Kona line. The most frequent (9.6%) allele in the Kona line (236 bp) was not observed in the Select line. Significant genetic differentiation between the two lines was shown using contingency table analysis (X2= 891.20, df = 33, P < 0.0001), the exact test ( P < 0.00001), and Fst, analysis (0.06). Comparison of MI allele frequencies between the TSVresistant Select and TSV-susceptible Kona lines and between the top 12.5% (Top Select) and the bottom 12.5% (Bottom Select) surviving families to TSV challenge in the Select line suggested associations of MI alleles with TSV resistance. These observations suggest testable hypotheses in future experiments aimed at finding genetic markers associated with resistance to TSV and markers that could be used for marker-assisted selection of broodstock.  相似文献   

19.
A specially designed recirculating system was used to maintain P. vannamei broodstock for maturation, mating and spawning in the same tank. Two groups of different size shrimp were stocked in this system in Phase I (8 May to 5 September 1989) and Phase II (5 September to 5 December 1989). Results showed that this recirculating system was able to maintain good water quality keeping broodstock maturing, mating and spawning with high stocking density (10 shrimp/m2) and low mortality (6%). Seventy-eight percent of spawned eggs were collected by a submerged egg collector. Mating success was very poor (3.4%) in Phase I even though there was normal spawning frequency. Mating success and nauplii production were much improved in Phase II. During Phase II 104 male and female broodstock housed in a 6 m3 tank produced 1.6 ± 106 nauplii (with 70% mating success) in three months. This study illustrated that broodstock size was a critical factor of successful mating and fertilization for P. vunnamei , and also, reduction of handling stress and lowered disturbance of the shrimp greatly enhanced the mating success.  相似文献   

20.
杨翠华  孔杰  王清印 《水产学报》2007,31(2):226-234
过量的捕捞和不合理的人工育种措施,使中国对虾野生和养殖群体的遗传多样性均遭到不同程度的降低。本试验在相似的环境条件下养殖了40个野生对虾产生的家系和3个兄妹交产生的家系,定量测定了平均体重(1.43~1.58) g 1 460尾中国对虾早期体重和感染白斑综合征病毒（WSSV）后存活时间的近交衰退系数。结果显示,野生对虾家系组的平均体重和平均存活时间分别为(1.58±0.01) g和(100.43±0.68) h,而兄妹交家系组平均体重和平均存活时间分别是(1.43±0.04) g和(85.84±1.70) h,平均体重和平均存活时间在两组间均存在极显著差异（P<0.01）。野生对虾家系组体重和存活时间的表型相关系数为0.16±0.00,而兄妹交家系组两者间的表型相关系数为0.20±0.00,但是两组间表型相关系数差异不显著（P>0.05）。近交系数每增加10％,体重和感染WSSV后存活时间分别衰退-3.80%±0.17%和-5.81%±0.11%,与近交能够降低生长和疾病抗性的观点相一致。实验结果表明,在选择育种和种质资源保护过程中都应该保证基础群体遗传背景最大化,从而有效控制近交。图0表2参39  相似文献   

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