成都平原主养草鱼·搭配鲫鱼池塘底泥中的细菌群落结构分析

[目的]分析成都平原主养草鱼、搭配鲫鱼池塘底泥中的细菌群落结构。[方法]通过构建细菌16SrRNA基因克隆文库,对阳性克隆子进行多样性分析和构建系统发育树。[结果]依据97％序列相似性划分OUT,所构建的文库共获得171个克隆子,并划分为14个OTUs（操作分类单元）,其多样性指数Shannon（日）和优势度指数Simpson（D）分别为2．12和7．15,丰富度指数Schaol和Schaol均为16。池塘底泥中主要的细菌类群为：梭杆菌门（24％）、变形菌门（55％）、浮霉菌门（10．5％）、绿弯菌门（5．9％）、拟杆菌门（2．3％）、放线菌门（1．8％）和厚壁菌门（0．6％）o[结论]Cetobacterium、Prolixibacter、Rhodocyclus、Candidate、Planctomycetacia、Thiocapsa、Desulfomicrobium和Sterolibacterium等属菌在脱氮除磷、降低硫化物、降解有机质等发挥重要作用。池塘底泥既是水生态系统修复功能菌的资源库,但也存在着Xanthomonas等致病性和功能未知的细菌库。     

3种硝基苯污染物对锦鲤鱼的急性毒性

采用静水生物测试研究了对氯硝基苯(P-NCB)、间二硝基苯(M-DNB)和2,4-二硝基氯苯(CDNB)对锦鲤鱼的急性毒性.以锦鲤鱼(Brocarded Carp)为试验生物,将其暴露于3种化合物不同浓度的试液中,通过鱼类的死亡率求出96 h半数致死浓度(LC50).试验结果表明,对氯硝基苯、间二硝基苯、2,4-二硝基氯苯96 h LC50分别为22.13、14.53、0.692 mg·L-1.对氯硝基苯、间二硝基苯和2,4-二硝基氯苯对锦鲤鱼的急性毒性顺序为2,4-二硝基氯苯＞间二硝基苯＞对氯硝基苯,3种化合物的安全浓度分别为2.213、1.453和0.069 2 mg·L-1,2,4-二硝基氯苯对锦鲤鱼的安全浓度低于地表水环境标准,间二硝基苯和对氯硝基苯安全浓度高于标准限值.     

鲤鱼冻藏期间品质变化的研究

以新鲜鲤鱼为原料,采用复合蒸煮袋(PE BOPP复合材料)包装,镀冰衣和未镀冰衣两种处理,在 18C冻藏5个月内,对样品进行感官检验、含水量测定、鱼肉pH值、总挥发性盐基氮的测定。结果表明,新鲜 切段鲤鱼块包装后,在-18C,镀冰衣鱼体可冻藏130d,未镀冰衣鱼块品质下降较快,仅可冻藏70 d。     

Variation in spawning responses, egg and larvae productions from induced rohu (Labeo rohita) during pre-monsoon and monsoon seasons: Relationship with hormonal changes and oocyte responsiveness during final maturation

Early induced spawning in captive rohu (Labeo rohita) often encounters with reduced spawning performances and devaluation of final product. The present study attempted to gain insight into the problems associated with poor performance of rohu during pre-monsoon spawning. A combination of sGnRHa and domperidone was used to induce final oocyte maturation (FOM) and ovulation in rohu during early (pre-monsoon, PM) and normal (monsoon, MN) spawning. The spawning performance parameters such as, spawning response, production and quality of egg and larvae showed significantly lower values (p < 0.05) in PM, when compared with MN spawning. The egg and spawn productions were recorded as 2.6 ± 0.05 and 2.41 ± 0.05 during the MN season, which were reduced by almost 50% in the PM season. Moreover the quality of egg and hatchling was devaluated significantly (p < 0.05) and exhibited higher percentage of mortality and abnormality in PM than those recorded in the MN season. The plasma concentration of carp gonadotropin (cGtH), 17β-estradiol (E) and 17α20β-dihydroxy-4-pregnen-3-one (DP) in relation to progress of FOM and ovulation at different seasons exhibited marked variation in hormonal profiles particularly in E and DP of PM fish. Higher initial plasma E (3.8 ± 0.3) and a distinct E peak clearly indicated the lack of transition from vitellogenic to post-vitellogenic stages that prevailed in PM rohu. Delayed DP and cGtH surge during FOM and ovulation resulted in longer latency period in spite of higher water temperature (31.5 °C) that prevailed during the PM period. In-vitro study on oocyte maturational competence (OMC) clearly depicted the lack of maturational competence in ovarian follicles during PM than MN in rohu. However priming the fish with purified carp gonadotropin (PCG) enhanced the acquisition of OMC in PM rohu in such an extent, that no marked seasonal differences (p > 0.05) in OMC were remained further, when compared with MN follicles. The PCG mediated acquisition of maturational competence was found to be dependent fully on new mRNA and protein synthesis in PM fish. The present study clearly demonstrated that the oocytes' unresponsiveness to hormonal induction was mainly responsible for reduced spawning performance in PM rohu, which could be ameliorated through PCG priming to achieve better spawning response in rohu during the pre-monsoon period. Thereby, the rohu fry production could be initiated successfully as early as May, allowing public and private hatcheries to produce larger age-0 rohu fingerlings ensuring reliable steady source of stocking materials for grow-out system earlier in the season.     

低pH水平对鱼类生理生化效应的影响研究

本文研究了低pH水平对鱼类血液电解质，血糖浓度和鳃组织酶活力影响。实验结果表明：低pH水平对鲤鱼血液K^ 的含量明显高于正常水平，Na^ 含量明显低于正常值，低pH为4．5－5．0时，鲤鱼血糖明显升高，体重下降，抑制生长，pH值为6．0时，21天起Na^ -K^ -ATPase酶活力明显下降，并有显著抑制作用（P＜0．05），历经30天有极显著抑制作用（P＜0．01）；pH值6．0加铝时，21天有极显著抑制（P＜0．01），抑制作用达到75％，pH5.5-5.0加铝时14天有极显著抑制（P＜0．01），抑制作用达到100％，pH4.5-4.0加铝时7天同样有极显著抑制（P＜0．01），抑制作用达到100％。     

文庆鲤酶解蛋白(EAP)的制备

以广东肇庆地区特产鱼种———文庆鲤为原料,通过筛选,选择枯草杆菌中性蛋白酶为实验用酶来制备文庆鲤酶解蛋白(EAP),并最终确定了最佳工艺条件:温度40℃,酶量2%,底物浓度1∶2,时间5.5 h。     

鲤鱼源粪肠球菌的体外抑菌试验研究

为证明益生菌候选菌株具有益生特性,将筛选的鲤鱼源粪肠球菌YL-1进行体外抑菌试验。结果发现,YL-1对病原菌嗜水气单胞菌有较强的抑菌作用;通过对YL-1上清液进行热处理,蛋白酶处理,中和酸等方式分析发现,其抑菌物质主要是对有机酸和胰蛋白酶敏感的一类物质。     

鲤鱼急性喹乙醇中毒的病理学研究

试验对鲤鱼进行了喹乙醇急性中毒的病理学研究。喹乙醇对鲤鱼 (60± 5g)口服给药的LD50 为 :32 4 9 4mg/kg体重。中毒鱼表现出特征性的“应激性出血症” ,鳍条基部、嘴部和腹部充血、出血发红 ,肠道排出白色半透明粘液便 ,临死前出现明显的神经症状。病理组织学上 ,肝脂肪变性或水泡变性及凝固性坏死 ,肾上腺空泡变性 ,肠呈卡他性肠炎 ,肾小管上皮细胞、心肌纤维空泡变性 ;鳃小片水肿 ,上皮增生、变性、坏死和脱落。超微结构上 ,心肌、肝和肾小管上皮细胞的线粒体肿胀 ,嵴断裂、溶解 ,肝细胞内糖原颗粒减少。中毒早期肠上皮微绒毛断裂 ,脱落 ,随着病程的发展肠上皮细胞变性、坏死、脱落。     

盐酸氯苯胍在异育银鲫体内的药代动力学研究

盐酸氯苯胍是防治鲫孢子虫病的常用药。为了给鲫养殖过程中的临床科学用药提供理论依据,在水温为(25±1)℃时,分别用20、30和40 mg/kg的剂量口灌质量为(120±10) g的异育银鲫,利用高效液相色谱法测定ROBH在其肾脏、肝脏、血液、肌肉等4种组织的药时曲线。结果显示,3种剂量给药下,异育银鲫各组织中的ROBH药时曲线均呈双峰现象。不同剂量的药物在异育银鲫血液中的达峰时间、血药质量浓度峰值、药时曲线下面积分别为:20 mg/kg,T_(max)=2. 3 h,C_(max)=0. 55 mg/L,AUC=9. 35 [(mg/L)·h]; 30 mg/kg,T_(max)=2. 1 h,C_(max)=0. 73 mg/L,AUC=13. 02 [(mg/L)·h]; 40 mg/kg,T_(max)=2. 2 h,C_(max)=1. 17 mg/L,AUC=13. 98[(mg/L)·h]。给药剂量相同时,ROBH在异育银鲫各组织中的药时曲线下面积呈现肾脏、肝脏、血液、肌肉由大到小的排列顺序。清除速率显示,ROBH在肌肉中清除最慢,其次是血液。ROBH在肾脏和肝脏中具有一定蓄积作用,主要表现在药物含量高、MRT值偏大。本实验条件下,ROBH在异育银鲫体内的休药期不低于9 d。但考虑到实际养殖情况和天气原因,临床休药期可根据实际情况适当延长。本文系首次在大宗淡水鱼中报道ROBH的药代规律,为包括鲫在内的大宗淡水鱼养殖科学用药提供一定的理论指导。     

鲫鱼冬瓜皮汤改善肾病综合征大鼠肾功能的实验研究

目的 观察鲫鱼冬瓜皮汤联合常规治疗方法对肾病综合征模型大鼠肾功能的保护作用。方法 将96只SD大鼠随机分为4组,分别为正常组、模型组、治疗组、对照组,对照组予以常规治疗,治疗组除常规治疗外,按照临床等效剂量予以鲫鱼冬瓜皮汤,连续14 d为一疗程,共治疗2个疗程。分别于治疗前、治疗2周及治疗4周后,检测大鼠肾组织病理形态学、24 h尿蛋白及肌酐、尿素氮、尿酸水平。结果 与治疗前相比,对照组、治疗组体质量差异有统计学意义（P<0.05）;与模型组比较,对照组与治疗组的体质量差异有统计学意义（P<0.05）,但对照组和治疗组相比,体质量无明显差异（P>0.05）。与模型组相比较,对照组远端小管排列较紧密,组织间可见少量炎性渗出;治疗组较对照组减轻。经过4周的治疗后,治疗组尿蛋白、肌酐、尿素氮、尿酸水平较治疗前显著下降（P<0.05）;与模型组比,治疗组指标有显著性改善（P<0.05）;治疗组与对照组比较差异具有统计学意义（P<0.05）。结论 采用鲫鱼冬瓜皮汤联合常规治疗方法可有效改善肾病综合征模型大鼠体质量比,减少其24 h尿蛋白及肌酐、尿素氮、尿酸水平。