Tropical fish medicine. Bacterial culture and evaluation of diseases of fish

Bacteria are ubiquitous in nature. Fish are constantly exposed to bacteria, and usually only succumb to an infection after having been exposed to prolonged periods of stress. Before making a diagnosis of a bacterial disease, it is necessary to eliminate the possibility of environmental or parasitic problems. Environmental factors may act as stressors and can predispose a fish to bacterial disease while affecting the fish simultaneously. Clinical signs caused by the various bacterial pathogens are very similar. Therefore, to make a definitive bacterial diagnosis, it is necessary to culture and identify the organisms involved.     

养殖鱼类品质评价指标体系的研究进展

随着我国渔业发展由"数量增长型"向"质量效益型"转变,鱼类品质逐渐受到消费者的关注。鱼类品质是一种综合性状,与人的感官有着密切联系并由一系列品质评价指标(包括物理性状和化学组成)所决定。本文从人的感官因素出发,对养殖鱼类品质评价指标体系进行综述,以期为通过饲料营养途径来提高养殖鱼类品质提供参考。     

Detection of salmonellae from fish in a natural river system

Sediment, water, and fish gut samples taken at three sites near the headwaters of the San Marcos River, Texas, were analyzed for salmonellae Salmonella spp. by culture and molecular techniques. While enrichment cultures from sediment and water samples from the two uppermost sites were negative for salmonellae in polymerase chain reaction analyses, both sediment and water samples were positive at the downstream site. At all sites, salmonellae were present in the guts of different fishes (e.g., largemouth bass Micropterus salmoides, channel catfish Ictalurus punctatus, common carp Cyprinus carpio, and suckermouth catfish Hypostomus plecostomus). The highest percentage of detection (33% of analyzed fish) occurred at the downstream site, whereas detection percentages at the upper two sites were 18% and 17%. Detection of salmonellae was usually limited to one segment of the gut (i.e., upper or lower part). Serovars were highly variable among individuals and differed between the upper and lower gut in the only individual (a common carp) that had salmonellae in both gut segments. In situ hybridization demonstrated that salmonellae were normally associated with particulate material in the gut and occurred in highly variable numbers ranging from an occasional organism to a majority of the gut microbe population. These results demonstrate the presence of different serovars of potentially human pathogenic salmonellae among four ecologically distinct fishes within natural environments. They also suggest that salmonellae are not components of the indigenous microbial community in fish intestines but rather are ingested with particulate material.     

人工养殖鲟鱼鱼头酶解蛋白粉的营养评价

采用超声脱脂预处理后双酶水解工艺得到人工养殖鲟鱼鱼头酶解蛋白粉。对鲟鱼头蛋白粉的营养价值进行了综合评价,结果表明:鲟鱼头酶解蛋白粉的营养成分:水分0.80%、灰分20.83%、总脂肪的平均含量1.50%、总糖含量0.30%、粗蛋白含量78.12%、纯蛋白含量48.77%。鲟鱼头蛋白粉还含有丰富的氨基酸,其中必需氨基酸占氨基酸总量的18.63%。蛋白粉的矿物质含量较丰富,特别是钙元素和硒元素的含量,分别达到了3.9×105 mg/kg及0.48 mg/kg。     

A survey of the fish fauna of Transkei estuaries Part Three: The Mtata River estuary

The species composition, seasonal abundance and spatial distribution of the fish fauna of the Mtata estuary (8,5 km long) was determined by means of gill nets. Nine hundred and ninety fish (462,9 kg) comprising 26 species were caught of which M. cephalus (43,3%), A. hololepldotus (18,9%), P. commersonnii (7,9%), machnata (7,1%) and L. amia (5,45) were most abundant in terms of biomass. Mullet species constituted 48,3% of the biomass caught, representing 25,6% of the numbers. Seasonal patterns were ascertained for M. cephalus, M. capensis, V. buchanani, A. hololepidotus, P. commersonnii, P. kaakan, £ machnata, L. amia, J. dussumieri, T. vitrirostris and L. equula. A mean of 19,4 fish with a mean mass of 9,1 kg were caught per net per station. Numerically the highest catches were made in the upper reaches; gravimetrically in the middle reaches. Temperatures ranged from 10,5-25,5°C; a salinity gradient was usually present in all reaches; oxygen levels and turbidities were high.     

Functional and ultrastructural evaluation of neutrophils from foals and lactating and nonlactating mares

Neutrophils from 4 pony foals, 3 lactating pony mares, and 3 nonlactating mares were evaluated ultrastructurally and by in vitro function tests. Neutrophils from foals had significantly (P = 0.05) less random migration than neutrophils from mares; values in tests for iodination and Staphylococcus aureus ingestion were also lower with foal neutrophils. Neutrophils from lactating mares had lower responses to iodination, antibody-dependent cell-mediated cytotoxicity, and random migration tests than did neutrophils from nonlactating mares. Ultrastructurally, granule concentration did not differ significantly among groups. A slight decrease in primary granules and a corresponding increase in granules with a flocculent matrix indicates partial spontaneous neutrophil degranulation in foals and lactating mares.     

The food legislation evaluation of environmental chemicals in freshwater fish

During the last 1 1/2 decades different regulatory limits have been given to value pollutants in fish under food-legal aspects. Their requested target, which consists of an effective consumer's protection however has been missed by various reasons: The production and distribution of environmental pollutants cannot be suppressed by limits for food. The selective elimination of limit-exceeding individuals from a lot is impossible. Treating both, natural pollutants like geogenic mercury and anthropogenic ones similar seems to be indefensible with regard to food law. Therefore proposals are made to rule only anthropogenic pollutants by law, when regulatory limits are planned to be supplemented. In case of natural distribution less stringent advisory limits seem to be more suitable.     

Further investigation of risk elements content in the bones of wild rodents from a polluted area in Slovakia

Background

Wild rodents are suitable for monitoring environmental pollution and exposure risk assessment for people living in contaminated areas. The content of selected risk elements in the femora of bank vole (Myodes glareolus), yellow-necked mouse (Apodemus flavicollis) and wood mouse (Apodemus sylvaticus) was estimated from the Kolíňany area of Slovakia, which is characterized by a high degree of environmental pollution. The rodents were trapped in February 2011 using standard theriological methods. All animals (n = 32) were adult males in good physical condition. The concentrations of Fe, Cu, Zn and Ni in their bones were determined by atomic absorption spectrophotometry.

Results

The highest concentrations of Fe and Cu were detected in the bones of yellow-necked mouse. Significant differences were observed for the content of Fe between A. flavicollis and M. glareolus (P < 0.05). The highest levels of Zn and Ni were found in the femora of wood mouse; however, significant differences were not detected between the rodents. Moreover, the concentrations of Cu, Zn and Ni were significantly higher in the bones of all three species (P < 0.05) in comparison with the values obtained in the same animal species at the same site in February 2007.

Conclusions

Our results demonstrate an increased accumulation of Cu, Zn and Ni in the femora of M. glareolus, A. flavicollis and A. sylvaticus from the Kolíňany area and thus indicate towards ongoing contamination of this locality.     

A survey of the fish fauna of Transkei estuaries. Part 1. The Kei River estuary

During the period of survey the 8 km long Kei estuary was subjected to periodic floods which reduced salinities to 0%o and decreased light penetration to a few centimetres. Species composition, and temporal and spatial abundance were determined for fish samples collected by means of gill nets. Twenty-six species of fish were caught with Mugil cephalus, Liza tricuspidens and Argyrosomus hololepidotus predominating, in that order. The family Mugilidae comprised 67,8% of the numbers and 66,6% of the fish biomass caught. Definite seasonal patterns could not be determined for many of the fish although M. cephalus, L. richardsoni and A. hololepidotus were more abundant in summer. The effect of river flooding had unpredictable results on Mugilidae catches which either decreased or increased after floods while catches of P. commersonii and A. hololepidotus usually increased. Largest catches were made in the middle reaches although species diversity was greatest in the lower reaches of the estuary.     

Surgical removal of a fish hook from the oesophagus of a turtle

An adult male Macquarie turtle was presented for examination after swallowing a fish hook. Radiographs taken to determine the position of this foreign body within the gastrointestinal tract revealed the fish hook lodged in the turtle's oesophagus. Surgical removal of the fish hook involved an approach through the soft tissues of the lateral neck. The turtle recovered well and was returned to the wild.     

Surgical removal of a fish hook from the oesophagus of a turtle

An adult male Macquarie turtle was presented for examination after swallowing a fish hook. Radiographs taken to determine the position of this foreign body within the gastrointestinal tract revealed the fish hook lodged in the turtle's oesophagus. Surgical removal of the fish hook involved an approach through the soft tissues of the lateral neck. The turtle recovered well and was returned to the wild.     

The fish community of the berg river estuary and an assessment of the likely effects of reduced freshwater inflows

Data concerning the species composition, abundance and distribution of fishes inhabiting the Berg River estuary are presented and used to assess the value of the estuary to fish, and the likely eflects of reduced freshwater inflows. A total of 31 species was recorded, eight of which were classified as estuarine residents, 11 as marine estuarine-opportunists, six as marine stragglers and six were freshwater species. Liza richard- sonii, an opportunist, was the most abundant (54% N) and widely distributed species encountered during the winter and summer seine-net surveys. Three other species (all residents) contributed more than 10% of the total catch; Atherina breviceps and Caffrogobius nudiceps occurring most abundantly in the lower estuary, and Gilchristella aestuaria in the middle estuary. The low number of species compared with estuaries in other regions of the South African coast reflect a well-established marine biogeographical trend. The higher proportions ol resident species, entirely dependent species and partially dependent species suggest, however, that west coast estuaries may be more important to the fish that inhabit them than are estuaries in other regions. It is concluded that the fish community of the estuary is already suffering the effects of habitat degradation and that further reductions in freshwater inllows are not desirable.     

利用鱼糜加工废弃物制备饲用鱼油的研究

为有效利用鱼糜加工废弃物,试验以过氧化值为指标,研究了以鱼糜加工废弃物制备鱼油的工艺条件,探讨了鱼油的提取(时间、温度、pH等)及精制工段对鱼油品质的影响,并对异维生素C钠、植酸钠、2,6-二叔丁基对甲酚(BHT)、特丁基对苯二酚(TBHQ)等抗氧化剂对鱼油的抗氧化效果进行分析。结果表明,鱼油适宜提取条件为温度85℃、pH为9.0、时间40 min,抗氧化剂以TBHQ效果最佳。     

Culture of macrophages from bovine bone marrow

Macrophages perform important immunoregulatory and host defense functions. Examination of this cell type in the bovine has been restricted because of lack of a means to obtain pure bovine macrophage populations reproducibly. We have developed a system for production of large numbers of macrophages from this species with greater than 99% purity. Stem cells were obtained from the bone marrow of neonatal calves and cultured in vitro in the presence of macrophage-colony-stimulating factor. Bovine bone marrow culture-derived macrophages were esterase-positive, expressed Fc receptors for aggregated IgG, and bovine macrophage differentiation markers. In addition, they displayed class I and class II major histocompatibility (MHC) antigens. The level of MHC antigen expressed could be further enhanced by treatment with recombinant bovine interferons. The macrophages exhibited expected functions, for example, Fc-mediated ingestion of opsonized sheep red blood cells. Augmentation of phagocytic capacity by either alpha or gamma interferon could also be demonstrated. The data reported here confirm that bone marrow culture is a convenient, reliable source of macrophages for investigations of this bovine cell type.     

翘嘴鳜苗当年养成商品鱼试验

翘嘴鳜是鳜鱼中生长速度最快的品种,为了缩短养殖周期,降低生产成本,提高经济效益,笔者于2005年在沅江市黄茅洲镇金南渔场主持了翘嘴鳜苗池塘当年养成商品鱼的试验,现将试验情况综述如下。1材料与方法1.1池塘条件翘嘴鳜养殖试验池1口,面积3335m2,水深2m,池底平坦,淤泥少;饵料鱼     

国内外关于鱼类胰蛋白酶的研究进展

胰蛋白酶（trypsin）是消化酶的一种,属于丝氨酸蛋白酶家族。胰强白酶是一种肽链内切酶,对由碱性氨基酸（精氨酸、赖氨酸）的羧基与其它氨基酸的氨基所形成的键具有高度的专一性。此外,还能催化由碱性氨基酸和羧基形成的酰胺键或酯键,其高度专一性仍表现为对碱性氨基酸一端的选择。胰蛋白酶对这些键的敏感性次序为：酯键〉酰胺键〉肽键。     

鱼粉的主要卫生学问题及评价方法

<正>鱼粉是畜、禽、水产饲料中一种非常重要的动物性蛋白质原料,它在饲料工业中的地位不容取代。目前,由于我国渔业资源相对匮乏,鱼粉的价格一直居高不下。本文主要从蛋白质鲜度指标、油脂新鲜度指标和霉变程度等几个卫生学指标对鱼粉的品质进行科学的评价。     

Isolation and characterization of macrophages from a mixed primary culture of bovine liver cells

Previously, we developed a simple and efficient method to isolate liver macrophages from a mixed primary culture of adult rat liver cells. To extend the applicability of this method, we isolated macrophages from mixed primary cultures of bovine liver cells. Macrophage cells proliferated on the cell sheet of mixed bovine liver cells after 8-16d of culture. These cells were detached by shaking of the culture flasks. Subsequent transfer and brief incubation in plastic dishes resulted in selective adhesion of macrophages. After rinses with PBS, attached macrophages were harvested. More than 10(6) cells could be harvested from the culture flask at intervals of 2-3d for more than three weeks. The isolated cells were strongly positive for bovine macrophage markers, such as CD68, CD172a and Iba-1. These cells exhibited functional properties of macrophages, including active phagocytosis of polystyrene microbeads, proliferative response to recombinant bovine granulocyte-macrophage colony-stimulating factor, upregulation of specific inflammatory cytokine genes upon stimulation with lipopolysaccharide, and formation of multinucleated giant cells. The shaking and attachment method provides a simple and efficient alternative to obtain bovine liver macrophages without requiring complex equipment or specialized technical skills.