草鱼不同混养模式下围隔底泥反硝化、硝化和氨化速率

应用乙炔抑制法测定了草鱼(Ctenopharyngodon idellus)不同混养模式围隔底泥的硝化、反硝化和氨化速率,以探究草鱼不同混养模式对池塘底泥－水界面N元素动态变化的影响,并为草鱼养殖模式的优化提供必要的参考依据.混养组合分别为一元组（草鱼）、二元组（草鱼+鲢、草鱼+凡纳滨对虾）、三元组（草鱼+鲢+凡纳滨对虾,设2种放养比例）.结果显示:1）草鱼不同混养模式中底泥的反硝化速率范围为0～734.15 μmol/(m2·d),硝化速范围为0～1 209.20 mmol/(m2·d),化速率范围为0～41.25 mmol/(m2·d).2)草鱼不同混养模式底泥的反硝化速率较高,与很多河口和湖泊数值接近;在养殖中期,底泥的硝化速率很小甚至检测不到;底泥的氨化速率呈逐月递增趋势,以三元混养组最高.3）混养组中凡纳滨对虾(Litopenaeus vannamei)的放养密度越大,草鱼的放养密度越小,反硝化作用出现得越早,但反硝化速率很难保持开始的水平;反之,反硝化作用出现得较晚,并会随着养殖周期的推移迅速升高;放养种类越单一,底泥的硝化速率越低,且鲢(Hypophthalmichthys molitrix)放养密度越高,硝化速率越高.从养殖模式优化的角度来看,草鱼三元混养组要优于单养和二元混养组,但三元混养组中两种放养密度各有优劣,有待进一步优化以确定最佳放养比例.     

不同施肥条件对土池培育小球藻总脂含量及脂肪酸组成的影响

以辽宁盘锦光合蟹业有限公司养殖基地为试验场所,研究施以3种肥料(化肥、鸡肥、化肥与鸡肥的混和肥)对土池培育小球藻的主要营养指标——脂质含量和脂肪酸组成的影响。试验结果表明,施混合肥所培养的小球藻,其藻细胞密度略高于化肥组和鸡肥组;混合肥组小球藻的脂质含量(鲜质量的5.36%)也高于化肥组(鲜质量的4.02%)和鸡肥组(鲜质量的2.89%);混合肥组小球藻的多不饱和脂肪酸和高度不饱和脂肪酸的含量显著优于单一施化肥或鸡肥的小球藻。因此,在土池中施混合肥更有利于培育出高质量的小球藻。     

低盐碱池塘养殖雅罗鱼及其杂交种肌肉营养成分分析

本研究旨在为池养雅罗鱼肌肉营养成分的评定和规模化配合饲料的配制提供基础数据。选取达里湖瓦氏雅罗鱼(Leuciscus waleckii,简称DL)、松花江瓦氏雅罗鱼(L.waleckii,简称SHJ)、高体雅罗鱼(L.idus,简称GT)以及种内杂交种(达里湖瓦氏雅罗鱼♀×松花江瓦氏雅罗鱼♂,简称DS)和种间杂交种(达里湖瓦氏雅罗鱼♀×高体雅罗鱼♂,简称DG)各15尾,每种鱼等量分成3组,测定其背部肌肉的一般营养成分、氨基酸和脂肪酸含量。结果显示:1)除水分含量无明显差异外,5种养殖雅罗鱼的灰分、粗蛋白和粗脂肪的含量均出现明显差异(P0.05)。其中DS杂交的灰分(1.77%)含量显著高于其他4种雅罗鱼(1.16%~1.22%),粗脂肪含量(7.23%)显著高于其双亲组合(DL 4.31%,SHJ 4.22%)及含量最低的DG杂交(3.32%),表现出超亲的杂种优势;5种养殖雅罗鱼具有较高的蛋白质含量(17.05%~18.80%),其中DG和DL的蛋白质含量明显高于其他3种养殖群体(P0.05),显示出较强的杂种优势;2)5种雅罗鱼肌肉中均测定出18种氨基酸,氨基酸总量(TAA)介于73.058%~79.289%,DG和DL的TAA含量、AAS、CS及EAAI指数均高于其他3种雅罗鱼,与其粗蛋白的测定结果相符,表明母本DL将其高蛋白的遗传特性很好地遗传给了子代,进一步证明了杂种优势;3)5种雅罗鱼肌肉中均检测到23种脂肪酸,饱和脂肪酸(SFA)、单不饱和脂肪酸(MUFA)和多不饱和脂肪酸(PUFA)含量分别为15.03%~19.06%、49.15%~53.92%和27.54%~29.40%,PUFA/SFA比值介于1.53~1.83;SFA和PUFA含量较高的是GT和DL,而MUFA含量较高的是DG和DS两个杂交种。综上所述,5种盐碱池塘养殖雅罗鱼的肌肉营养成分较均衡,属优质蛋白质;杂交选育可以有效改善杂交种的肌肉营养品质,获得的高脂高蛋白的DS杂交和低脂高蛋白的DG杂交可以满足不同的市场需求。     

放养密度和微生态制剂对施氏鲟养殖水质的影响

将初始体质量(54.86±10.19)g的施氏鲟Acipenser schrenckii饲养在面积16m~2(4m×4m)、水深1.7~1.9m的陆基围隔中,密度分别为2 000尾/667m~2、3 000尾/667m~2、4 000尾/667m~2和5 000尾/667m~2,每个密度组均设3个平行,常规饲养,混合泼洒光合细菌、枯草芽孢杆菌和乳酸菌,第一次泼洒量为光合细菌50m L、枯草芽孢杆菌50g和乳酸菌50g,之后每5d泼洒第一次量的1/2,研究微生态制剂对静水土养殖池塘水质的影响。结果显示:水体中溶解氧量随养殖密度的增加逐渐降低(P0.05),氨氮、亚硝酸盐浓度随养殖密度的增加逐渐升高(P0.05)。在使用微孔增氧的条件下,泼洒微生态制剂对溶解氧量和氨氮浓度的影响不显著(P0.05),但显著降低了水体亚硝酸盐浓度(P0.05),显著增加了浮游动物生物量(P0.05)。     

应用高通量测序技术分析拟穴青蟹肠道及其养殖环境菌群结构

采用基于Illumina Hi Seq测序平台的高通量测序技术,对拟穴青蟹(Scylla paramamosain)肠道及其养殖池塘水体、底泥中细菌种类及丰度进行了研究。测序结果显示,3个样品共获得有效序列234575条,可聚类于2812个分类操作单元(OTUs),归属于拟穴青蟹肠道、养殖水体、池塘底泥样品的操作分类单元(OTU)个数分别为453、706和2547,其中有184个OTU均能在3个样品中检测到,在青蟹肠道和养殖水体、青蟹肠道和池塘底泥中分别检测到197和309个共有OTU。物种注释结果显示,拟穴青蟹肠道中优势细菌种类为变形菌门(Proteobacteria)(39.96%)、柔膜菌门(Tenericutes)(23.09%)和厚壁菌门(Firmicutes)(16.58%);养殖水体中优势细菌种类为变形菌门(63.02%)、放线菌门(Actinobacteria)(24.96%)和拟杆菌门(Bacteroidetes)(8.41%);池塘底泥中优势细菌种类为变形菌门(75.23%)、拟杆菌门(5.72%)和放线菌门(3.83%)。此外,对各样品中丰度最高的前10位OTU分析显示,不同样品中占优势地位的10种细菌在数据库(SILVA)缺乏相关已知序列,并且各样品中的优势细菌种类完全不同。实验结果表明拟穴青蟹肠道与其池塘养殖环境中菌群结构存在着密切的相关性,但肠道菌群同时具有一定的独立性,其优势细菌种类与养殖环境中优势细菌种类无关。本研究旨在为拟穴青蟹健康养殖和微生态调控提供实验依据。     

绍兴市凡纳滨对虾围垦滩涂养殖池塘的理化环境和浮游植物

2016年和2017年分别调查了位于浙江省绍兴市滨海新区的12口凡纳滨对虾围垦滩涂养殖池塘内的理化环境和浮游植物。结果显示:池塘内盐度变化范围为0~2,溶氧为6.2~13.9 mg/L,pH为7.5~9.8,总氨氮(TAN)为0.00~0.72 mg/L,亚硝酸盐氮(NO_2~--N)为0.00~1.70 mg/L,硝酸盐氮(NO_3~--N)为0.18~4.77 mg/L,总氮为1.74~6.08 mg/L,总磷为0.20~2.72 mg/L,总有机碳为1.88~42.57 mg/L,C/N为10~39。池塘内浮游植物种类隶属6门、24科、42属,其中蓝藻和绿藻为优势种。浮游植物生物量为(0.15~2.30)×107cell/L,叶绿素a(Chl.a)为2.62~37.24μg/L。Chl.a与蓝藻生物量显著正相关。NO_2~--N和NO3--N均与pH显著负相关。初步分析认为高pH可能是导致2016年池塘养殖凡纳滨对虾死亡率较高的重要原因,因此采取措施控制蓝藻生物量和水体的p H应有助于提高对虾养殖的存活率。     

杂交鳢和乌鳢池塘养殖对比试验

对杂交鳢和乌鳢进行池塘养殖对比试验.前者投喂人工饲料,后者投喂冰鲜鱼,结合水质调控和病害防治等技术,杂交鳢成活率80.9%,乌鳢53.9%;杂交鳢平均单产为5.2 kg/m~2,饵料系数1.367;乌鳢1.8 kg/m~2,饵料系数4.29.整个养殖过程杂交鳢塘换水2次,乌鳢塘换水6次.     

断斑石鲈土池人工育苗研究

本文报道2001－2005年断斑石鲈人工育苗的初步研究结果。在水温23－30.5℃、海水盐度27－32,pH值7.8－8.9的条件下,初孵仔鱼经27日龄－39日龄变态为幼鱼,全长达24－46mm;2001年、2002年及2005年先后培育出幼鱼27006尾、62000尾及240008尾,育苗成活率分别为6%、13.8%和26.9%。文中还介绍了饵料系列、鱼苗生长与发育及形态观察研究结果。     

Impact of pond management on tambaqui, Colossoma macropomum (Cuvier), production during growth-out phase

This study evaluated the impact of pond management on tambaqui, Colossoma macropomum (Cuvier), rearing during the growout phase. Juvenile tambaqui were stocked in ponds with three different management regimes: (1) natural ponds (Nat); (2) limed ponds (Lim); and (3) limed and bimonthly fertilized ponds (LimFer). The experiment lasted 210 days and the growth parameters were evaluated monthly. Water quality and effluent measurements were performed every 15 days and at the end of the experiment yield parameters were obtained. There was no difference in weight and length among treatments. Stomach contents and zooplankton availability were not influenced by pond management, but the rearing period had an influence on them. Food conversion rate (FCR) was better in fish from the Lim treatment than in fish from the Nat treatment. The pH, hardness and alkalinity values were significantly higher in the Lim and LimFer ponds, where the liming procedure was performed. The effluent analysis showed a more potentially impacting effluent in the LimFer treatment, where phosphorus and orthophosphate concentrations showed values significantly higher than those in Lim and Nat ponds. The results show that the Lim treatment is the best approach, as in this treatment fish achieve market size, better FCR, yield and have a reduced environmental impact.     

Effects of blue shrimp Litopenaeus stylirostris and goldlined rabbitfish Siganus lineatus in mono‐ and polyculture on production and environmental conditions

This study was conducted to compare the effects of shrimp and rabbitfish in mono‐ and polyculture stocked at high biomass on production and environmental conditions in a mesocosm system. Shrimp (14 g) and/or rabbitfish (19 g) were stocked in four treatments with different density but with the same total biomass (236 g m^?2), including shrimp monoculture (SM) (17 shrimp m^?2), shrimp–fish polyculture (SF) (11 shrimp and 4 rabbitfish m^?2), fish–shrimp polyculture (FS) (6 shrimp and 8 rabbitfish m^?2) and fish monoculture (FM) (12 rabbitfish m^?2). After 10 weeks of experiment, shrimp survival and biomass were low in the treatments where shrimp were dominant (SM, SF), while rabbitfish survival and biomass were high in all the treatments. Shrimp mortality was assumed to be related to an excess of the system carrying capacity (CC). Results suggested that CC is linked to shrimp biomass/density rather than the system eutrophication level. The ecosystem became heterotrophic as daily feed supply was beyond 7 g m^?2 per day. This threshold corresponded to the environmental CC of the semi‐intensive shrimp culture system. Under these conditions, the combination of high fish biomass and low shrimp biomass appeared as the most valuable in terms of system performances.