温度对中华绒螯蟹雌蟹繁殖性能及胚胎质量的影响*

Effects of temperature on reproductive performance and embryo quality of female Eriocheir sinensis

中文关键词: 温度  中华绒螯蟹  繁殖性能  胚胎质量  脂肪酸

英文关键词: Temperature  Eriocheir sinensis  reproductive performance  embryo quality  fatty acids.

中文摘要:

      为探究温度对中华绒螯蟹（Eriocheir sinensis）雌蟹繁殖性能及所产胚胎质量的影响，开展了不同温度（6℃、9℃、12℃、15℃、18℃、21℃）下亲蟹的繁殖产卵实验，分析了各温度下雌蟹的交配率、产卵率、产卵量和生殖力等繁殖性能以及所产胚胎卵径、生化成分和脂肪酸组成等胚胎质量。结果表明：（1）随温度的升高，亲蟹的交配率逐渐增加，产卵率、产卵量、生殖力和生殖指数均呈先上升后下降的趋势，其中温度15℃时，雌蟹的产卵率、产卵量、生殖力以及生殖指数均最高，且与其它各温度组都有显著差异（P＜0.05）。（2）温度18℃时，所产胚胎卵径最大，平均为（431.17±13.69）μm，15℃时，单个胚胎干重最重，平均为（31.28±4.61）μg，但与18℃组无显著差异（P＞0.05）。（3）随温度的升高，胚胎中灰分和磷脂呈逐渐增加的趋势，总脂肪则逐渐下降，甘油三酯和总胆固醇表现为先升高后降低，粗蛋白和水分的变化不明显。其中18℃时，胚胎中粗蛋白、甘油三酯和总胆固醇含量均最高。（4）中华绒螯蟹胚胎中共检测出21种脂肪酸，其中饱和脂肪酸（SFA）和单不饱和脂肪酸（MUFA）在温度12℃下总量最高，但与其它各组无显著差异（P＞0.05）。6℃下胚胎所含C20:5n3（EPA）、C22:6n3（DHA）、C20:4n6（ARA）和多不饱和脂肪酸（PUFA）的总量均最高。研究表明，温度对中华绒螯蟹所产胚胎质量有一定影响，15℃时中华绒螯蟹繁殖性能最佳。结果为开展中华绒螯蟹繁育生物学研究提供了基础资料，同时也为长江口中华绒螯蟹渔业资源养护提供了科学支撑。

英文摘要:

      The Chinese mitten crab (Eriocheir sinensis) is an important economic species in China, and its reproductive performance and embryo quality are particularly important for the quality of newly hatched larvae. E. sinensis is a weak thermoregulator among crustaceans. From November to May every year, the broodstock crabs complete mating and spawning and early larval development in the Yangtze River Estuary. During this period, they are more sensitive to environmental changes. Too low or too high water temperature will have a direct or indirect effects on the breeding of E. sinensis. Therefore, temperature is an important environmental factor affecting the breeding of E. sinensis. In order to explore the effects of temperature on the reproductive performance and embryo quality of female E. sinensis, the reproduction and oviposition experiments of parent crabs at different temperatures (6 °C, 9 °C, 12 °C, 15 °C, 18 °C, 21 °C) were carried out. Three parallel groups were set up for each temperature, three samples were taken for each parallel groups. The reproductive performance of females at different temperatures, such as the mating rate, spawning rate, spawning volume and fertility, as well as the quality of the embryos produced, such as the egg diameter, the dry weight of a single egg and the wet weight of embryos, were analyzed through observation and calculation. The crude protein content of embryos was determined by Kjeldahl method; the total fat content was determined by acid hydrolysis method; the composition and content of fatty acids were detected by gas chromatography; the moisture content of embryos was determined by taking 2~3 mg of wet embryos from each temperature group and drying them at 70°C until constant weight; the ash content was determined by burning them at 550°C until constant weight; and the content of triglyceride, phospholipids, and cholesterol was determined by enzyme immunoassay kit. The enzyme-linked immunoassay kit was used to determine triglyceride, phospholipid and cholesterol. The results showed that: (1) With the increase of temperature, the mating rate of parent crabs increased gradually, and the spawning rate, spawning capacity, fecundity and reproductive index all increased first and then decreased. When the temperature was 15 °C, the spawning rate, spawning capacity, fecundity and reproductive index of female crabs were the highest, with the averages of (80±10)%, (15.38±1.81)×104 grains/only, (0.23±0.03)×104 grains/only and (20.01±1.59)%, respectively, and there were significant differences with other temperature groups (P<0.05). (2) At 18 °C, the egg diameter of the embryos was the largest, with an average of (431.17±13.69) μm. At 15 °C, the dry weight of a single embryo was the heaviest, with an average of (31.28±4.61) μg, but there was no significant difference between the 15 °C group and the 18 °C group (P>0.05). (3) With the increase of temperature, the content of ash and phospholipids in embryos increased gradually, while the content of total fat decreased gradually. The content of triglyceride and total cholesterol increased first and then decreased, while the content of crude protein and water did not change significantly. The contents of crude protein, triglyceride and total cholesterol in embryos were the highest at 18 °C, with an average of (20.83±1.72)%, (26.2±0.71) μmol/g and (97.3±1.19) μmol/g, respectively. (4) A total of 21 fatty acids were detected in the embryos of E. sinensis, of which saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) were the highest at 12 °C, but there was no significant difference with other groups (P>0.05). The total contents of C20:5n3 (EPA), C22:6n3 (DHA), C20:4n6 (ARA) and polyunsaturated fatty acids (PUFA) in embryos at 6 °C were the highest, with an average of (4.26±0.85) mg/g, (4.93±0.79) mg/g, (2.96±0.44) mg/g and (22.74±3.22) mg/g, respectively. This study showed that temperature had a certain effect on the quality of embryos produced by Chinese mitten crab, and the reproductive performance of Chinese mitten crab was the best at 15 °C. The study provide basic data for the study of breeding biology of E. sinensis, and also provide scientific support for the conservation of fishery resources of E. sinensis in the Yangtze River estuary.