Influence of duration of aeration on growth and survival of carp fingerlings during high density seed rearing

Impact of varied durations of aeration on growth, survival and production performances of catla (Catla catla), rohu (Labeo rohita), fringe lipped carp (Labeo fimbriatus) and olive barb (Puntius sarana) were evaluated in outdoor concrete tanks (10 m × 5 m × 1.3 m) during fingerlings rearing. At a combined stocking density of 0.5 million fry/ha, provision of night time aeration for 4, 8 and 12 h was evaluated as the three treatments, T-I, T-II and T-III, respectively against control (T-c, without aeration). Overall survival and net biomass of the species increased among the treatments significantly as a function of aeration hours (T-c < T-I < T-II < T-III). Aeration for 8 and 12 h showed significantly higher survival, harvested body weight and SGR in all the carps than those with 4 h (T-I) and no aeration (T-c), suggesting 8–12 h of aeration requirement for fingerlings rearing at such high density. Further, no significant difference between survival levels in T-II and T-III groups suggested 8 h of aeration to be adequate. However, while species-wise performance showed 8–12 h night time aeration to be advantageous for catla and rohu, aeration for 4 h was adequate for fringe lipped carp and olive barb.     

Sample digestion for determining chloramphenicol residues in carp serum and muscle

Chloramphenicol (CAP) residues in carp (Cyprinus carpio L.) were investigated after intramuscular injection of a single-dose of 80 mg/kgbw. CAP concentrations in carp serum and muscle with and without addition of β-glucuronidase were determined by high-performance liquid chromatography (HPLC) with UV detection. The results showed that CAP-glucuronide (CAP-G), an important conjugate of CAP in the metabolic process and potentially toxic to human health, was observed after the fish were injected with CAP. CAP concentrations in serum and muscle with added β-glucuronidase were significantly (p < 0.05) higher than those without added enzyme. For example, within 24 h of injection, average CAP concentrations in serum and muscle with enzyme digestion were 30 and 48% more than those without the enzyme. In order to exactly determine the trace CAP content of fish, for evaluation of food safety, it is suggested that samples be hydrolyzed with enzyme (e.g., β-glucuronidase).     

Olive barb, Puntius sarana (Hamilton) is a potential candidate species for introduction into the grow-out carp polyculture system

The compatibility of olive barb, Puntius sarana (Hamilton) with major carps was studied in grow-out carp polyculture system for one year in a set of nine earthen ponds of 0.08 ha each. Three different species combinations evaluated were Control: catla (Catla catla Ham.), silver carp (Hypophthalmichthys molitrix Valenciennes), rohu (Labeo rohita Hamilton) and mrigal (Cirrhinus mrigala Hamilton) at 0.5:0.5:1:1; T1: catla, silver carp, rohu and olive barb at 0.5:0.5:1:1 and T2: catla, silver carp, mrigal and olive barb at 0.5:0.5:1:1 at combined density of 7500 fingerlings/ha. While survival levels of the carps did not differ significantly in treatments (P > 0.05), silver carp recorded highest survival levels (94–96%) followed by olive barb (87–90%), mrigal (72–74%), rohu (72–73%) and catla (67–69%). The specific growth rate (SGR) and average harvested body weight (ABW) of catla and silver carp did not differ significantly among the treatments revealing their competition with mrigal or olive barb to be minimum. In absence of rohu in T2, both mrigal and olive barb showed higher SGR and ABW revealing minimal competition between these two species, while their lower performance in presence of rohu in Control and T1 indicated inter-specific competition with the latter. Such olive barb–rohu inter-specific competition, however, failed to yield significant effect on growth of rohu as revealed from its non-significant SGR difference in presence and absence of olive barb. The lower FCR (2.54 ± 0.06) and higher treatment biomass production (3418.4 ± 95.0 kg ha^− 1 year^− 1) in T1 with rohu–olive barb combination compared to T2 with mrigal–olive barb (2.84 ± 0.11; 3155.1 ± 104.7 kg ha^− 1 year^− 1) indicated feasibility and advantage of culturing rohu with olive barb rather than mrigal in carp polyculture. Further, similar biomass production in Control and T1 also indicated feasibility of replacing mrigal with olive barb in the grow-out carp polyculture system.     

EM对建鲤血液指标及耗氧率的影响

用微生态制剂ＥＭ作为饲料添加剂饲养建鲤，经４５天的实验，结果表明：实验组建鲤和生长比对照组快，红细胞数和血红蛋白含量均高于对照组，而耗氧率低于对照组。     

中国淡水鱼类单极虫病的研究Ⅰ.河南信阳鲤鱼单极虫病的研究

1993年作者对河南信阳市南湾水库网箱养殖鲤鱼肠道单极虫病进行了系统研究。该地区发病率高达 90 %以上 ,发病鲤鱼肠壁上寄生了大量单极虫孢囊 ,破坏肠道组织 ,吸收鱼体营养 ,病鱼失去光泽 ,体色呈暗黑色 ,肠管呈紫红色 ,充满脓血粘液 ,大型孢囊集中在中、后肠 ,孢囊形态大多为椭球形 ,最大个体为 4 .5× 2 .5cm ,肠管膨大一倍以上 ,肠壁变薄 ,肠道完全被堵塞 ,停止进食而死亡。经比较研究 ,该病原体被定为信阳单极虫新种 (Thelohanellusxinyangensissp .nov .)。作者对感染和未感染鲤鱼血清进行了免疫试验 ,发现病鲤血清蛋白带比未感染粘孢子虫鲤鱼血清多 5— 7条 ,该血清与单极虫孢子经交叉免疫电泳发生沉淀反应 ,表明病鲤血清具有特异性抗体产生。作者在病鲤血液中还发现“未明血液生物体”(UBO) ,对肝、肠组织亦进行了病理学研究     

异育银鲫上皮瘤病发病池与未发病池的水质分析

[目的]探讨水环境因子与异育银鲫上皮瘤病发生与发展的关系。[方法]2007年9月～2008年2月,每月下旬对异育银鲫上皮瘤病发病较为严重的裕安淡水养殖场的37个养殖池水质进行测定分析,其中20个养殖池为发病池,17个养殖池为未发病池。[结果]结果表明,水质测定除2007年9月份发病池N03-N与未发病池有显著性差异（P〈0．05）外,其他月份发病池与未发病池中的pH值、NH3-Nt、NH3-Nm、NO2-N、NO3-N、COD和SRP均无显著性差异（P〉0．05）。6个月的水质测定期间,发病池和未发病池中的NH3-Nm含量分别为（0．051±0．020）和（0．158±0．141）mg／L;2007年9、10和12月份发病池和未发病池的NO2-N含量均超过了0．1mg／L;无论发病池还是未发病池SRP含量在水质测定期间均高于精养鱼池SRP最适含量0．010—0．030mg／L的上限值。NH3-Nm、NO2-N和SRP偏高的协同作用可对鱼体免疫功能造成更大的损伤,增加异育银鲫对疾病的易感性,在病毒病原存在的条件下可促进该病的发生和发展。[结论]该研究为异育银鲫上皮瘤病的防治提供理论依据。     

聚六亚甲基胍对异育银鲫造血器官坏死症的防治效果研究

分别采用腹腔注射含鲤疱疹病毒Ⅱ型(Cyprinid herpesvirusⅡ,Cy HV-2)的组织浆和患病鱼直接感染的方法进行人工感染实验,并对实验鱼发病组织病毒DNA进行巢式PCR检测,将扩增产物进行测序比对,研究聚六亚甲基胍(Polyhexamethylene guanide,PHMG)对异育银鲫(Carassius auratus gibelio)感染鲫造血器官坏死症(Crucian Carp Hematopoietic Necrosis)的防治效果。结果显示:两种人工感染的方法出现相似的感染症状,但后者感染周期相对较短;实验毒株与Gen Bank中已报道的Cy HV-2毒株的DNA解旋酶基因具有高度同源性(99.0%),该毒株与JSSY、YC110907等Cy HV-2其他病毒株属同一分支。药物预防实验表明:当PHMG浓度≥0.5 m L/m3时,保护率可达60%以上,对该病有显著抑制作用。治疗实验表明,药物对感染3 d后的鲫具有显著抑制作用,当PHMG浓度≥0.75 m L/m3时,保护率达63.33%以上,对该病有较好的治疗效果;当PHMG浓度≥2.5 m L/m3时,对感染5 d后的鲫具有显著抑制作用,保护率达63.33%以上。低浓度的药物治疗效果虽不显著,但可延长病鱼的存活时间。     

利用异源精子激发雌核发育的银鲫及亲本的RAPD分析

方正银鲫是黑龙江水系营天然雌核发育的两性型种群,这已被许多研究结果证实。但是从八十年代中期以来,国内一些研究者对该鱼的雌核发育特性,提出了不同的看法。一般认为银鲫的雌核发育机制同种或异种精子进入卵子后只刺激其发育,并不发生雌雄原核的结合,精子进入卵子后固缩成致密状态,并不形成雄性原核。也就是说子代的发育只是在雌原核的参与下进行的,子代完全继承母本的遗传特性[沈俊宝等1983]。但1983年蒋一王圭等用鲫、红鲫和兴国红鲤的精子刺激银鲫卵子发育,发现其子代(称异育银鲫)的生长较母本不同程度加快了,个别个体鳞被出现红斑,同…     

在饲料中添加柑橘或甜橙外果皮对鲤鱼诱食作用的比较研究

在基础饵料中不同量（０．０５％、０．１％、０．２５％、０．５％、１％、３％）的柑橘或甜橙外果皮,用记录仪记录鲤鱼啄咬饵料球的频率和力。表明,柑橘和甜橙外果皮是２种新的鲤鱼诱食物物质,而且二者对鲤诱食作用的效果基本相同,其适宜添加量分别为０．２５％或０．１％。