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牙鲜幼鱼能量代谢的初步研究   总被引:21,自引:1,他引:20  
对个体重2.5~87.6g的牙鲆幼鱼的代谢进行测试。结果表明:温度和体重对牙鲆幼鱼的耗氧率及二氧化碳排出率有明显的影响;牙鲆幼鱼的呼吸商为0.82±0.08,氧氮比为23.8±6.6,其能源物质以蛋白质和脂肪为主;牙鲆在盐度为30、25、20和15的水中,平均代谢率分别为3.08、3.07、3.87和3.28J/g·h,说明牙鲆幼鱼适盐较广,在本实验盐度阈值内,对鱼体代谢基本没影响。  相似文献   
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从山西北、中、南部地区天然沙棘林集中分布区所选的优良单株上采集硬技插穗,进行不同浓度、不同处理时间的扦插对比试验,从生根率、成活率、生长特性等方面研究了不同种源间硬技扦插效果的差异。分析结果表明:北、中、南三个种源间在同种处理方式下的生根率、成活率、苗高之间差异显著,中部种源表现最好;同一种源在不同处理方式下的生根率、成活率、地径之间差异显著,苗高差异不显著,右玉种源在0. 6%"劲茂"生根粉溶液中浸泡10 min表现最好,因此,可作为沙棘扦插育苗最优处理方式。  相似文献   
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人工诱导栉江珧雌核发育的初步研究   总被引:4,自引:0,他引:4       下载免费PDF全文
利用紫外线诱导进行栉江珧(Atrina pectinata)雌核发育单倍体的研究,用强度为2 561μW/(cm2.s)的紫外线(254nm)照射不同时间的精子与正常卵子受精展开实验。结果发现随照射时间的增加,卵裂率、早期胚胎存活率和D型幼虫发生率总体呈下降趋势,遗传失活的精子与正常卵子受精后其胚胎发育至D型幼虫前期停止。经紫外线照射的精子受精后所产生的单倍体胚胎发育速度慢于正常受精所产生的二倍体胚胎,各照射组均出现非整倍体。40 s照射组中卵裂率达到51.2%,D型幼虫发生率为0,单倍体率最高,达到36.8%,出现“Hertwig效应”。由于雌核发育单倍体的有效诱导既需要精子遗传物质失活、又需要保证较高的卵裂率,因而在强度2 561μW/(cm2.s)的紫外线下照射40 s是获得栉江珧雌核发育单倍体的最佳条件。  相似文献   
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This experiment was conducted to investigate the effects of dietary Ampitheoe sp. powder on the growth and the contents of astaxanthin, triglyceride (TG), total cholesterol (TCHO) and fatty acids of Litopenaeus vannamei. A total of approximately 6 777 L. vannamei with an initial body weight of (1. 80 ± 0.72) g were randomly divided into 3 groups, and there were 3 replicates (753 shrimp per replicate) in each group. Those shrimp fed diets containing 0 (D0 group), 8. 25% (D8. 25 group) and 33% (D33. 00 group) Ampitheoe sp. powder, respectively. The feeding trial lasted for 40 days. The results showed as follows: 1) the final body weight, weight gain rate, specific growth rate, yield and survival rate in D33.00 group were significantly higher than those in D0 group (P <0.05), whereas the feed conversion ratio was significantly lower than that in D0 group (P <0.05) . However, there was no significant difference between D33.00 group and the D8. 25 group in those indexes (P >0.05) . 2) The astaxanthin content in carapace, hepatopancreas and muscle of L. vannamei in D8.25 and D33. 00 groups was significantly higher than that in D0 group (P < 0. 05); that in D33.00 group was significantly higher than that in D8. 25 group (P < 0. 05) . 3) TG content in haemolymph, hepatopancreas and muscle in D8. 25 and D33. 00 groups was significantly lower than that in D0 group (P < 0.05); the TCHO content in hepatopancreas in D8. 25 group was significantly higher than that in D0 and D33.00 groups (P <0.05); TCHO content in muscle in D33.00 group was significantly higher than that in D0 group (P <0.05) . 4) The contents of eicosapentaenoic acid (EPA) and arachidonic acid (AA) in hepatopancreas in D33.00 group were significantly higher than those in D0 group (P <0.05) . The EPA content in muscle in D33.00 group was significantly higher than that in D0 group (P < 0. 05) . In conclusion, adding Ampitheoe sp. powder into the diet can improve the growth performance, the contents of astaxanthin, EPA and AA in L. vannamei, and affect the accumulation of TG and TCHO, which can be used as a functional diet in aquaculture. Considering the cost, the supplementation level of 8. 25% Ampitheoe sp. powder is more appropriate. © 2023 Chinese Journal of Pediatric Surgery. All rights reserved.  相似文献   
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