几种淡水养殖鱼死后僵硬的季节变化

几种淡水养殖鱼活杀死后在室全僵的时间（Ｔｒ）同其生活时的水温（ｔ）之间存在着良好的负相关，即ｌｎＴｒ＝５．０３７－０．１１６５ｔ（ｒ＝－０．９２３６），显示出明显的季节差异。死后僵硬还受致死方法影响，表现为活杀鱼的僵硬时间长，挣扎死的短，半死的近于二者之间。据此，讨论了在温度低，僵硬期长的季节，采用冰藏或１０℃以常温条件下活杀鲜鱼流通上市，拓宽淡水养殖鱼类流通渠道的可能性及活杀鲜鱼的鲜度质量指标等     

草鱼出血病细胞培养弱毒疫苗的制备及其免疫效果

本文报道经筛选的ＧＣＨＶ－８４１毒株在草鱼吻端成纤维细胞系中进行适应性培养，弱毒驯化，细胞培养弱毒疫苗的制备，安全性观察，不同稀释度和剂量的免疫保护率测定及保存试验，ＧＣＨＶ－８４１毒株在ＰＳＦ细胞中继代驯化至５３代达到减毒目的。筛选得５３－５９代作毒株在ＰＳＦ细胞中继代驯化至５３代达到减毒目的，筛选得５３－５９代作毒种制备的细胞制备细胞弱毒疫使用安全，用稀释１０－１０＾４倍的疫苗，０．１－０．３     

超高压对草鱼肌肉超微结构与质构特性的影响

研究了等静超高压对草鱼肌肉超微结构与质构特性的影响，并与猪肌肉用对照。结果表明：１．加压处理的草鱼肌肉，其超微结构中出现较明显的变化，如肌原纤维中Ａ带和Ｉ带的细丝均被破坏，粗丝相互聚集，出现间隙，Ｚ线变粗，不连续，Ｈ带和Ｍ线消失等，但肌原纤维的外形仍保持完整。２加压处理的草鱼肌肉，其外观无显著变化，色泽稍白，略有汁液流出，但质构特性与处理前无明显差别。     

Growth testing of two breeds of common carp, Cyprinus carpio L. (Hungarian mirror and Třeboň scaly carp), in ponds with low and high stocking density

The growth of two breeds of common carp, Cyprinus carpio L., was tested in ponds under the climatic conditions of South Bohemia. T?eboň scaly carp (TR) and Hungarian mirror carp (M2) were kept in both low and high stocking densities during the second growing season and then stocked together for communal testing during the third growing season. Before the communal testing, the mean initial weights of fish from low‐ and high‐density stocks differed significantly (374.1 vs. 227.7 g for the TR breed and 766.7 vs. 317.3 g for the M2 breed respectively, P<0.01). After communal testing, mean weights of fish from low‐ and high‐density stocks gained 761.8 vs. 543.8 g for the TR breed and 1339.7 vs. 706.7 g for the M2 breed respectively. These observed weights were also significantly different (P<0.01). However, the test of corrected weight gain, i.e. gain not related to the initial weight of fish, revealed insignificant differences (P>0.01) between the weight gains after correction, i.e. the effect of different initial weights was successfully eliminated. These results seem to confirm the applicability of this method for the assessment of growth of purebred common carp under the climatic conditions of Central European fish farms.     

The evaluation of secondary stress response of grass carp (Ctenopharyngodon idella, Val. 1844) after exposing to the saline water

The stress response of grass carp to salinity was evaluated assessing the levels of hematocrit, leucocrit, plasma glucose, sodium, potassium and calcium. Mean hematocrit values increased following exposure to salinity. Mean leucocrit values elevated after exposure to salinity for 24 h, then decreased. Mean plasma glucose increased during saline exposure for 48 h and then decreased to normal values. Plasma sodium and chloride levels were increased to their highest values after 48 h. While plasma potassium value increased with the exposure time, plasma calcium values were not affected by salinity exposure.     

Dynamics of appetite in three fish species (Gasterosteus aculeatus, Phoxinus phoxinus and Carassius auratus gibelio) after feed deprivation

The temporal dynamics of appetite (weight of food consumed per day) were analysed for fish fed to satiation after a 1 or 2-week period of feed deprivation. Three species were compared: two omnivores (minnow, Phoxinus phoxinus and gibel carp, Carassius auratus gibelio) and a carnivore (three-spined stickleback, Gasterosteus aculeatus). All species showed compensatory changes in appetite and growth during the re-feeding period but in the stickleback, there was a lag of a week before the compensatory response was detected. The temporal dynamics of appetite differed between the three species but not within a species. Appetite of the minnow declined towards control levels from the onset of re-feeding. In gibel carp, appetite increased to a peak and then declined to control levels. In the stickleback, appetite was initially below control levels, increased to a maximum, then declined towards control levels. The differences between the species might have been artefacts of the experimental protocols used but could also reflect underlying differences in the control of appetite in these species of fish.     

The purification and partial characterization of carp,Cyprinus carpio,vitellogenin

A procedure is described for the isolation of intact vitellogenin (c-VTG) from the carp, Cyprinus carpio. VTG was induced in juvenile females using oestradiol-17β and purified from the plasma using a combination of gel-filtration chromatography on Sepharose 6B and ion exchange chromatography on DEAE-cellulose. Purification procedures were conducted at low temperatures (below 9°C) in the presence of the proteolytic enzyme inhibitor aprotinin to prevent degradation. Intact c-VTG had an apparent molecular mass of 390,000 Daltons, but when extracted from plasma in the absence of aprotinin it underwent proteolysis into at least 2 protein fragments (apparent molecular masses of 230,000 and 96,000 Daltons), showing an instability of the native dimer. An amino acid analysis of c-VTG showed that its composition was almost identical to goldfish VTG, a species closely allied to the true carps and also similar to other oviparous vertebrate VTGs. Collectively, these data indicate that using these purification procedures VTG from carp, and probably other teleost species, can be isolated in an intact, highly purified form.     

草鱼出血病的病原研究

草鱼出血病的病原研究,始于50年代。1978—84年,分离到一种病原病毒,定名为草鱼呼肠孤病毒或鱼呼肠孤病毒。本文报道从出血病病鱼组织的电镜研究中发现两种病毒颗料,一种即是呼肠孤病毒,另一种是20-30nm大小的病毒。经病毒的核酸分析,前者是双股RNA病毒;后者为单股RNA病毒。用分离到的这两种病毒分别注入1足龄健康草鱼,可发生两类不同症状的出血病;呼肠孤病毒主要导致“肠出血型”症状;另一种病毒(经初步鉴别属于小RNA病毒科病毒)主要导致“肌肉出血型”出血病。由此,可以证实两种病毒都是草鱼出血病的病原病毒,同时也初步解释出现两种不同症状出血病的原因。     

Comparison of food selection and growth performance of koi carp, Cyprinus carpio L., and goldfish, Carassius auratus (L.) in mono- and polyculture rearing in tropical ponds

To compare the effect of polyculture against conventional monoculture on ornamental carp production, investigations on food selection and growth performance of koi carp (K), Cyprinus carpio L. and goldfish (G), Carassius auratus (L.) were conducted in a 11‐week rearing experiment in two monoculture (100% K and 100% G) and five polyculture (90% K–10% G, 70% K–30% G, 50% K–50% G, 30% K–70% G and 10% K–90% G) conditions in tropical ponds. There were three replicates for each treatment. Environmental conditions and food availability were similar in all the treatments. Ivlev's electivity index showed that both fish species avoided phytoplankton and preferred cladocerans to other zooplankton groups (copepods and rotifers) in monotypic conditions. However, in the polyculture treatments, the positive electivity of goldfish towards cladocerans reduced significantly (P<0.05), while the percentage of copepods, rotifers and phytoplankton in the gut content increased. No significant differences in weight gain, specific growth rate and deformities were recorded at harvest for koi carp between the different treatments (P>0.05). Even the survival rate of koi carp recorded above 90% in all the treatments. However, the goldfish recorded significantly better weight gain, specific growth rate and survival in monoculture (100% G), compared with the polyculture treatments (P<0.05). Goldfish deformities were lowest (P<0.05) in the monoculture treatment (2.42%). The number of marketable fish above a set size limit of 4 g total weight was significantly higher in the two monoculture treatments, compared with the five polyculture treatments (P<0.05). Keeping in view of the dietary similarities of koi carp and goldfish, and the aggressive nature of koi carp in polyculture, it is suggested to refrain from polyculture of goldfish and koi carp until further documentations relating to optimum stocking density and management of polyculture of ornamental carps are available.     

Comparison of 5′-inosine monophosphate and p-nitrophenyl phosphate degrading activities among red,pink, and white muscle fibers of cultured carp

ABSTRACT:   As part of a study to clarify the differences in the temporal change in K -value among fish species, the temporal change in K -value and the 5'-inosine monophosphate (5'-IMP) and p-nitrophenol phosphate (p-NPP) degrading activities in the red, pink, and white muscle fibers in the dorsal muscle of the carp were compared. The temporal change in K -value was fastest in red, followed by pink, and white muscle fibers, at both 0°C and 32°C. Moreover, the 5'-IMP and p-NPP degrading activities were highest in red, followed by pink, and white muscle fibers at near optimum pH concentrations. The 5'-IMP degrading activity at pH 7.0 had a positive correlation with the increasing rate of K -value at 32°C for all types of muscle fibers. These results suggest that differences in increasing rates of K -values between red, pink, and white muscle fibers corresponded to the 5'-IMP degrading activities.