【作者】 严美姣；

【导师】 熊邦喜； 李钟杰；

【作者基本信息】 华中农业大学 ， 水产养殖， 2004， 博士

【摘要】 利用实验生态学的方法，研究暗纹东方鲀(Takifugu fasciatus)对盐度的适应性，以及在人工养殖条件下的生物学特性。研究内容包括盐度对暗纹东方鲀的生长、饲料利用、标准代谢、消化酶活性、血清渗透压的影响和暗纹东方鲀的人工繁殖、苗种培育技术，仔鱼对常用药物的毒性反应。此外，还初步研究了盐度和饲料蛋白水平对暗纹东方鲀的生长和生化组成的影响。主要结果如下： 1．0~+龄暗纹东方鲀在盐度为8‰、18‰、25‰、35‰和淡水中饲养6周，在盐度为35‰的死亡率为100％，摄食、生长和饲料利用在其他各盐度间无显著差异。1~+龄暗纹东方鲀在盐水为8‰、18‰、35‰和淡水中饲养8周，在盐度为8‰时生长最快，各盐度间特定生长率有显著差异，摄食率和饲料系数无显著差异。 2．在不同盐度中预处理过的1~+龄鱼直接转移到淡水中饲养，结果是在高盐度中驯养过的实验鱼呈现出补偿生长，在低盐度中驯养过的鱼前后生长无显著差异。补偿生长是通过提高摄食率和饲料转化效率实现的。 3．在盐度为8‰、18‰、30‰的水体中饲养14d，0~+龄和1~+龄暗纹东方鲀消化酶的活性有不同程度的提高。以淀粉酶活性为评判指标，0~+龄和1~+龄鱼的适宜盐度均为18‰。0~+龄和1~+龄鱼在3种盐度条件下，胃蛋白酶活性都出现先升高后降低的趋势。0~+龄鱼的胰蛋白酶活性在8‰条件下，前2d内快速升高，然后下降；1~+龄鱼在18‰和30‰的条件下是先下降然后升高。 4．1~+龄鱼在盐度为8‰、18‰、35‰的水体中标准代谢率高于在淡水中的代谢率，各盐度中代谢率无显著性差异。0~+龄鱼昼夜代谢率变化规律是从早上8：00到下午2：00期间，代谢水平较高且随着时间的后移，代谢率逐渐降低。下午2：00到晚上10：00之间无明显规律，以后又随着时间的推移代谢水平缓慢升高。 5．体重约24g的实验鱼在盐度为8‰、18‰、30‰和淡水条件下，摄食粗蛋白含量分别为37.7％和43.2％的配合饲料，特定生长率最大值出现在盐度为18‰和低蛋白组。高蛋白饲料组特定生长率随盐度升高而增加，低蛋白饲料组在淡水、8‰、18‰3个处理中随盐度升高而增加，到30‰又降低。摄食率摘要随盐度和饲料蛋白水平的变化与特定生长率的变化趋势一致。饲料转化效率最小值出现在淡水和低蛋白组中;最大值出现在盐度为18编和高蛋白组中。鱼体干物质含量随盐度的增加而增加，除30编处理组外，低蛋白饲料组的鱼体干物质含量比高蛋白组的高。盐度和蛋白水平对鱼体能值、脂肪及灰分含量无显著影响。暗纹东方纯在人工养殖条件下，性腺能发育成熟，可进行人工催产繁殖。前期培育经历巧天，仔鱼成活率达70%。当暗纹东方纯体重范围为123一213.29时，摄食率随体重的增加而减少，由12.6%降到2.6%。更多还原

【Abstract】 Based on methods of experimental ecology, the biological characteristics of pufferfish T. fasciatus under controlled conditions were studied, with special respect to artificial reproduction, breeding techniques, toxic responses of larvae to common chemicals, and effects of water salinity on food intake, growth, feed utilization, standard metabolism, serum osmolality and digestive enzyme activity. The effects of salinity and protein levels on growth and biochemical composition of T. fasciatus were also investigated. The main results are as follows.1. Reared in water salinity of 8%0, 18%o, 25%o, 35%o and fresh water for 6 weeks, the yearling fish shows no significant differences in feeding rate, growth and food conversion ratio among treatments, except that the mortality in 35%o is 100%. As to 2-year-old fish, growth rate is greatest in 8%o; specific growth rates (SGR) are significant different among treatments; and feeding rate and food conversion ratio are not significantly different.2. After transfer to freshwater directly, the 2-year-old fish pretreated with high salinity shows compensatory growth and higher feeding rate than which with lower salinity. The fish pretreated with 8%o and 18%o shows no significant difference in growth, feeding rate and food utilization.3. In order to estimate the activity of digestive enzyme, T. fasciatus was reared in 8 %o, 18%o, 30%o salinity for 14 days. The results show that salinity can enhance digestive enzyme activity. The optimal salinity of yearling and 2-year-old fish are both 18%o based on amylase activity; Pepsin activities of both ages have a similar variation trend with water salinity; Trypsin activity of yearling fish increase sharply within 2 days in 8%. and then decrease, There is a slight drop followed by an elevation in trypsin activity of 2-year-old fish.4. Standard metabolic rate of 2-year-old fish reared in saline water are higher than that in freshwater and there are no significant differences among three salinities.Standard metabolic rate of yearling fish exhibite a higher level and remained a decrease tendency during the time of 8:00 am to 2:00 pm. After 10:00 pm the metabolism level descend gradually.5. Juvenile pufferfish were reared in 0, 8%o, 18%o, 30%o water salinity to examine growth and food utilization. Fish under each treatment was fed with formulation diets of two protein levels, i.e. 37.7% and 43.2%, respectively for 8 weeks. The results show that the maximum SGR appear in the mesohaline and low protein level group. SGR of the fish fed with diet of high protein level increase with the increment of salinity; SGR of the fish fed with low protein level rise firstly with the increase of salinity and then drop at the highest salinity level. Feeding rates indicate the same variation tendency as that of SGR, and the food conversion efficiency (FCE) has a minimum value (61.3%) which appears in freshwater and low protein group, and a maximum of 83.9%, which is in 18%o and high protein level group. The dry matter content of fish body has a positive relationship with salinity. According to the present results, the suitable salinity to the juvenile is 18%o and optimum dietary protein content is about 37.7%.6. Gonad of reared T. fasciatus can become mature under controlled conditions without migration. Survival rate of larva 15 days after hatched is 70%.7. Feeding rate decrease from 12.6% to 2.6% when fish body weight ranges from 12.2 g to 213.2 g.更多还原