不同动物饵料对YY超雄黄颡鱼性腺发育的影响

通过比较近10年YY超雄黄颡鱼的生产和养殖记录,发现仅近几年投喂过水蚯蚓的YY超雄黄颡鱼性腺出现问题。实验设定4组不同饵料(丰年虫、浮游动物、红虫和水蚯蚓)连续投喂YY黄颡鱼鱼苗20 d(11～30日龄),选择60日龄统计各组YY超雄黄颡鱼的存活率、体长和体质量。水蚯蚓组YY超雄黄颡鱼的体长和体质量显著高于其他3组,丰年虫组YY超雄黄颡鱼存活率显著低于其他3组。解剖观察60日龄和1年龄YY黄颡鱼的性腺结构并统计1年龄YY超雄鱼的受精率,结果显示,水蚯蚓组YY超雄黄颡鱼的性腺有75%为兼性性腺(精巢和卵巢均存在),25%为无精小叶的精巢,且1年龄的YY黄颡鱼受精率仅为36.70%±4.05%,并显著低于其他3组,而其他3组性腺发育和受精率均正常。为研究水蚯蚓引起YY黄颡鱼雌性化具体原因,实验测量4种不同动物饵料的雌二醇含量,发现雌二醇含量均较低,推测YY超雄黄颡鱼雌性化的原因可能是水蚯蚓富集的环境内分泌干扰物(EDCS)导致。研究表明,在YY超雄黄颡鱼大规格苗种培育过程中,早期应投喂浮游动物或红虫,不宜投喂水蚯蚓。     

Impacts of agricultural practices on aquatic oligochaete populations in ricefields

Summary The impacts of N fertilizer, pesticides and green manure on aquatic oligochaetes in irrigated ricefields were investigated in experimental plots. Populations, determined by the wet sieving of soil cores, were dominated by the Tubificidae Limnodrilus hoffmeisteri. Total densities ranged from 0 to 40 000 m^-2. Oligochaete numbers increased in response to additions of urea N. An inhibitory effect of carbofuran on oligochaete populations was observed during the first season of experimental pesticide treatments, but not during the following year. The green manure Sesbania rostrata stimulated population development more than Azolla microphylla. Populations in plots maintained as wet fallow remained low throughout the crop cycle. Population dynamics were associated with the crop cycle. Peak densities were achieved 30–50 days after transplanting.     

颤蚓污泥减量影响因素研究

[目的]探讨颤蚓污泥减量效果的影响因素。[方法]通过批次试验,考察了颤蚓对不同来源、不同浓度活性污泥的减量效果。[结果]MLVSS/MLSS值是影响颤蚓污泥减量效果的重要因素。对于不同污泥浓度的活性污泥,颤蚓的污泥减量效果存在明显差别,高污泥浓度下颤蚓的污泥减量效果更加明显,Y值与初始MLVSS值有较好的线性关系。[结论]为颤蚓污泥减量化的实际应用提供了理论依据。