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Comparison of chromosome banding analysis, interphase- and hypermetaphase-FISH, qualitative and quantitative PCR for diagnosis and for follow-up in chronic myeloid leukemia: a study on 350 cases.

For the diagnosis of CML and for monitoring of treatment response the detection of the t(9;22)(q34;q11) or the BCR-ABL rearrangement is necessary. Chromosome banding analysis (CA) is still the gold standard but other techniques like Southern blot, fluorescence in situ hybridization (FISH) and polymerase chain reaction (PCR) are available. We analyzed 350 CML patients at different stages of disease in parallel with CA, interphase-FISH (IP-FISH), hypermetaphase-FISH (HM-FISH) and RT-PCR. In 20 cases with no Ph(+) metaphases in CA, HM-FISH detected 0.2 to 10% BCR-ABL(+)metaphases. After IP-FISH 107 samples were judged as negative. However, in 17 of these samples HM-FISH detected BCR-ABL(+) metaphases (0.3-11%), and in eight cases CA detected Ph(+) metaphases (2.5-25%). A comparison of IP-FISH performed on uncultivated cells vs cells cultivated for 48 h in 70 cases revealed a higher proportion of BCR-ABL+ cells in the cultivated samples. If nested PCR was negative, all other methods were negative in all cases too. In addition, 94 cases were evaluated using real-time PCR (LightCycler technology). The BCR-ABL/cABL ratio measured showed a high correlation with all other methods. Interestingly, a wide range in the BCR-ABL/ABL ratio was observed especially in patients who showed 100% Ph-positive metaphases in CA. In conclusion, CA, IP-FISH, HM-FISH and real-time PCR give reliable results but differences due to measurement of different target structures have to be kept in mind when using these data for definition of remission status.

B-Lymphocytes↗

Mammalian immunoassays for predicting the toxicity of malathion in a laboratory fish model.

This study describes the use of a panel of immune assays, originally developed by the National Toxicology Program for assessing xenobiotic-induced immunotoxicity in mice, to quantify the effects of sublethal malathion exposure on the immune responses of fish. For this study, Japanese medaka (Oryzias latipes) were exposed subchronically to the organophosphate pesticide malathion in a series of two experiments. In the first set of studies, fish were exposed for 7 or 14 d to untreated well water (i.e., controls) or to waterborne malathion at 0.2 or 0.8 mg/L. Following exposure, fish from each group were sacrificed and their kidneys (primary organ of leukopoiesis in fish and equivalent to mammalian bone marrow) were used to provide cells for assessing any malathion-induced effects upon nonspecific and acquired immune defense mechanisms. Effects upon humoral-mediated immunity were determined by enumerating antibody plaque-forming cell (PFC) numbers from a subset of fish exposed to malathion for 14 d and then injected intraperitoneally (ip) with sheep erythrocytes (sRBC). Results of these studies demonstrated that while malathion exposure had no significant effect upon hematocrit/leukocrit values or upon mitogen-stimulated T-cell lymphoproliferation, PFC numbers in the kidney of exposed fish were significantly reduced (compared to control fish) in a dose-dependent manner. In addition, total recoverable kidney cell numbers and viability, as well as superoxide anion production by kidney phagocytes, were reduced slightly (compared to control values) in fish exposed for 14 d to the highest malathion concentration tested. In the second set of experiments, medaka exposed for up to 21 d to either 0.1 or 0.3 mg malathion/L were challenged ip with an LD50 dose of the bacterial fish pathogen Yersinia ruckeri. Results from these infectivity studies demonstrated that exposure to either malathion concentration, for 14 or 21 d reduced host resistance against Yersinia infection. Taken together, these findings demonstrate the applicability of mammalian immune assays for predicting malathion-induced immunosuppression in a teleost fish, as well as the potential utility of a small laboratory fish to serve as an alternate model for mammals in immunotoxicological studies.

Animals↗

Effects of National Cholesterol Education Program Step 2 diets relatively high or relatively low in fish-derived fatty acids on plasma lipoproteins in middle-aged and elderly subjects.

The effects of two National Cholesterol Education Program (NCEP) Step 2 diets (< or = 30% of energy as total fat, < 7% of energy as saturated fat, and < 200 mg cholesterol/d), one relatively high and the other relatively low in fish-derived fatty acids, on plasma lipoprotein concentrations and blood pressure were compared in 22 men and women with a mean (+/- SD) age of 63 +/- 10 y. Subjects were placed on a baseline diet similar to the diet currently consumed in the United States (35% of energy as total fat, 14% of energy as saturated fat, 35 mg cholesterol/MJ) for 6 wk and then on either an NCEP Step 2 diet relatively high in fish (Step 2 high-fish, n = 11) or relatively low in fish (Step 2 low-fish, n = 11) for 24 wk. All food and drinks were provided. Compared with baseline values, consumption of both the Step 2 high-fish and the Step 2 low-fish diets under weight-stable conditions was associated with significant decreases in plasma concentrations of total cholesterol (-14% and -19%, respectively), low-density-lipoprotein (LDL) cholesterol (-15% and -20%, respectively), and high-density-lipoprotein (HDL) cholesterol (-11% and -17%, respectively). Postprandial, but not fasting, triacylglycerol concentrations were significantly reduced during consumption of the Step 2 high-fish diet. There were no significant changes in these indexes after consumption of the Step 2 low-fish diet compared with the baseline diet. LDL particle size decreased significantly (-12%) only in subjects on the Step 2 low-fish diet. Both Step 2 diets caused small but significant reductions in diastolic blood pressure. Our results indicate that NCEP Step 2 diets relatively high or relatively low in fish are both effective in significantly reducing total and LDL-cholesterol concentrations without changes in the ratio of total cholesterol to HDL cholesterol under controlled weight-stable conditions in middle-aged and elderly subjects. A beneficial effect on diastolic blood pressure was also observed.

Aged↗

Fluorescence in situ hybridization (FISH) on touch preparations: a reliable method for detecting loss of heterozygosity at 1p and 19q in oligodendroglial tumors.

Combined loss of heterozygosity (LOH) on 1p and 19q is reported in 50% to 90% of oligodendroglial tumors and has emerged as a strong and favorable prognostic factor. Fluorescence in situ hybridization (FISH) and polymerase chain reaction (PCR) are the most widely used techniques. The aim of this study was to evaluate the reliability of FISH to predict LOH at 1p and 19q when performed on touch preparations from 40 oligodendroglial tumors, even if the majority of the nuclei showed chromosomal imbalance. PCR was used as the gold standard. The presence of none or one target signal was reported as FISH-LOH, whereas all other losses were defined as FISH-imbalance. The sum of nuclei with FISH-LOH and imbalance was calculated in each case (FISH-sum) and cut-off values were defined as the mean FISH-sum value in controls plus 3 standard deviations; 27.7% for 1p and 33.2% for 19q. These corresponded well with the optimal cut-off values for our data, calculated using the minimum error rate classification procedure (35.6% for 1p and 33.1% for 19q). Concurrent FISH and PCR results were encountered in 95% for 1p and 87.5% for 19q. FISH-sum was the best and simplest discriminating variable for correct classification of LOH status. Under these conditions, even a dominant population of nuclei showing FISH-imbalance represented an LOH status in the tumor cells. FISH on touch preparations is a quick and reliable method for 1p/19q testing, does not require normal DNA and can be easily performed in an immunohistochemistry unit.

Adult↗

Multi-locus (ML)-FISH is a reliable tool for nondisjunction studies in human oocytes.

In the present study, we developed a fluorescence in situ hybridization (FISH) strategy, which allows a reliable determination of the chromatid number of specific chromosomes in mature human oocytes. 168 unfertilized oocytes were analyzed by dual-color FISH with two direct-labeled locus-specific DNA probes for chromosome 13 and 21. To exclude FISH failures, metaphases with abnormal signal patterns were reanalyzed by multi-locus-FISH (ML-FISH) for chromosome 13 and 21. Following dual-color FISH, abnormal signal patterns were detected in 21 out of 108 metaphases (19.4%). 17 of these metaphases were reanalyzed by ML-FISH. In contrast to the first FISH, seven metaphases showed normal signal patterns after rehybridization, whereas ten metaphases remained abnormal. Out of these real aneuploid metaphases, five showed gain or loss of a single signal (= chromatid), two showed missing double signals (= chromosome) and three showed both. In conclusion, locus-specific FISH probes facilitate differentiation between first meiotic nondisjunction of whole chromosomes and prematurely divided chromatids. Moreover, simultaneous hybridization with a second locus-specific probe on the same chromatid (ML-FISH) helps to differentiate between FISH failures and real meiotic division errors and therefore, allows a more reliable analysis of aneuploidies in human oocytes.

Adult↗

Changing patterns of infection with digenetic larval trematodes from fresh-water fish in river Taewha, Kyongnam province.

Recent patterns of infection with digenetic larval trematodes in fresh-water and brackish-water fish were studied in three locations of the river Taewha during the period from April to October 1988, and compared with the data reported previously in the same river. Of 16 species of fish examined, the encysted larvae of Cyathocotyle orientalis were found most frequently from 9 species of fresh-water fish. The metacercariae of Echinochasmus sp., Metacercaria hasegawai and Metagonimus yokogawai were found 8 species, those of Clonorchis sinensis from 7 species, and Exorchis oviformis and Metorchis orientalis from 5 species of fish. The infection rates of fish with C. sinensis metacercariae were not lower than those reported in 1980, wheres their intensity of infection was found lowered in 3 species, Coreobagrus brevicorpus, Gnathopogon atromaculatus, and Puntungia herzi. The infection rates of 3 species of fish with M. yokogawai metacercariae were lower than the results in 1982, while the rate was higher in 2 species, Zacco platypus, and Z. temmincki, and rather stationary in Plecoglossus altivelis. The intensity of infection in several species of fish appeared rather higher than in 1980. the encysted larvae of C. orientalis, Echinochasmus sp., E. oviformis and Metacercaria hasegawai showed variations in infection rates of fish in 1980 and in the present study. It was found that the rate of infection with digenetic larval trematodes in fresh-water fish was still relatively high in the river Taewha, and the metacercarial burden in the fish varied greatly by different fish in 1980 and in the present study.

Journal Article↗

Prevalence and survival of Listeria monocytogenes in Danish aquatic and fish-processing environments.

Listeria monocytogenes contamination of ready-to-eat food products such as cold-smoked fish is often caused by pathogen subtypes persisting in food-processing environments. The purpose of the present study was to determine whether these L. monocytogenes subtypes can be found in the outside environment, i.e., outside food processing plants, and whether they survive better in the aquatic environment than do other strains. A total of 400 samples were collected from the outside environment, fish slaughterhouses, fish farms, and a smokehouse. L. monocytogenes was not detected in a freshwater stream, but prevalence increased with the degree of human activity: 2% in seawater fish farms, 10% in freshwater fish farms, 16% in fish slaughterhouses, and 68% in a fish smokehouse. The fish farms and slaughterhouses processed Danish rainbow trout, whereas the smokehouse was used for farm-raised Norwegian salmon. No variation with season was observed. Inside the processing plants, the pattern of randomly amplified polymorphic DNA (RAPD) types was homogeneous, but greater diversity existed among isolates from the outside environments. The RAPD type dominating the inside of the fish smokehouse was found only sporadically in outside environments. To examine survival in different environments, L. monocytogenes or Listeria innocua strains were inoculated into freshwater and saltwater microcosms. Pathogen counts decreased over time in Instant Ocean and remained constant in phosphate-buffered saline. In contrast, counts decreased rapidly in natural seawater and fresh water. The count reduction was much slower when the natural waters were autoclaved or filtered (0.2-microm pore size), indicating that the pathogen reduction in natural waters was attributable to a biological mechanism, e.g., protozoan grazing. A low prevalence of L. monocytogenes was found in the outside environment, and the bacteria did not survive well in natural environments. Therefore, L. monocytogenes in the outer environment associated with Danish fish processing is probably of minor importance to the environment inside a fish production plant.

Animals↗

Mercury effects on predator avoidance behavior of a forage fish, golden shiner (Notemigonus crysoleucas).

Mercury contamination of fish is widespread in North America and has resulted in the establishment of fish consumption advisories to protect human health. However, the effects of mercury exposure to fish have seldom been investigated. We examined the effects of dietary mercury exposure at environmental levels in a common forage species, golden shiner (Notemigonus crysoleucas). Fish were fed either an unaltered diet (12 ng/g wet wt methylmercury [MeHg] as Hg), a low-Hg diet (455 ng/g Hg), or a high-Hg diet (959 ng/g Hg). After 90 d mean fish whole-body total Hg concentrations were 41, 230, and 518 ng/g wet wt, respectively, which were within the range of concentrations found in this species in northern U.S. lakes. There were no mortalities or differences in growth rate among groups. Groups of fish from each treatment were exposed to a model avian predator and their behavioral response videotaped for analysis. Brain acetylcholinesterase (AChE) activity was determined in fish after behavioral testing. Fish fed the high-Hg diet had significantly greater shoal vertical dispersal following predator exposure, took longer to return to pre-exposure activity level, and had greater shoal area after return to pre-exposure activity than did the other treatments, all of which would increase vulnerability of the fish to predation. There were no differences in brain AChE among treatments. We conclude that mercury exposure at levels currently occurring in northern United States lakes alters fish predator-avoidance behavior in a manner that may increase vulnerability to predation. This finding has significant implications for food chain transfer of Hg and Hg exposure of fish predators.

Acetylcholinesterase↗

Fluctuations in human milk long-chain PUFA levels in relation to dietary fish intake.

Within the Danish population, milk DHA (22:6n-3) levels vary by more than a factor of 10. This paper deals with fluctuations in the milk content of 22:6n-3 and other long-chain PUFA (LCPUFA) and the acute effects of fish meals and fish oil supplements on milk levels of LCPUFA. Twelve fish-eating mothers with 4-mon-old infants provided one blood and one adipose tissue sample, and seven consecutive morning hind-milk samples with dietary records from the previous days. Another 12 lactating women were given fish oil (2-8 g) for breakfast and delivered 6-12 milk samples during the following 24 h. The mean milk 22:6n-3 content of the fish-eating mothers was 0.57+/-0.28 FA% (= percentage of total area of FAME peaks in GLC) and the day-to-day variation (SD/mean) within the individual was 35+/-17%. Mean milk 22:6n-3 content on mornings with no fish the day before was 0.42+/-0.15 FA%; this was increased by 82+/-17% (n = 9, P = 0.05) if the mother had eaten fatty fish. Fish oil resulted in a twofold increase in milk 22:6n-3 levels, which peaked after 10 h and lasted for 24 h. The EPA content of milk was also increased by fish meals and fish oil supplements, but these had no effect on the level of arachidonic acid. The study showed that diurnal and day-to-day fluctuations in levels of milk n-3 LCPUFA are large, which makes it difficult to assess the 22:6n-3 intake of breast-fed infants from a single milk sample. In studies of the functional outcome of dietary 22:6n-3 in breast-fed infants it is suggested also to use a measure of maternal 22:6n-3 status.

Diet↗

Nested assemblages resulting from host size variation: the case of endoparasite communities in fish hosts.

Nested species subsets are a common pattern in many types of communities found in insular or fragmented habitats. Nestedness occurs in some communities of ectoparasites of fish, as does the exact opposite departure from random assembly, anti-nestedness. Here, we looked for nested and anti-nested patterns in the species composition of communities of internal parasites of 23 fish populations from two localities in Finland. We also compared various community parameters of nested and anti-nested assemblages of parasites, and determined whether nestedness may result simply from a size-related accumulation of parasite species by feeding fish hosts. Nested parasite communities were characterised by higher prevalence (proportion of infected fish) and intensities of infection (number of parasites per fish) than anti-nested communities; the two types of non-random communities did not differ with respect to parasite species richness, however. In addition, the correlation between fish size and the number of parasite species harboured by individual fish was much stronger in nested assemblages than in anti-nested ones, where it was often nil. These results were shown not to be artefacts of sampling effort or host phylogeny. They apply to both assemblages of adult and larval parasites, which were treated separately. Since species of larval parasites are extremely unlikely to interact with one another in fish hosts, the establishment of nestedness appears independent of the potential action of interspecific interactions. The species composition of these parasite communities is not determined from within the community, but rather by the extrinsic influence of host feeding rates and how they amplify differences among parasite species in probabilities of colonisation or extinction. Nested patterns occur in parasite communities whose fish hosts accumulate parasites in a predictable fashion proportional to their size, whereas anti-nested communities occur in parasite communities whose fish hosts do not, possibly because of dietary specialisation preventing them from sampling the entire pool of parasite species available locally. Thus, nestedness in parasite communities may result from processes somewhat different from those generating nested patterns in free-living communities.

Animals↗

Blood pressure and atherogenic lipoprotein profiles of fish-diet and vegetarian villagers in Tanzania: the Lugalawa study.

BACKGROUND: There is evidence that populations with a high intake of fish, and specifically fish oils, are at reduced risk of cardiovascular disease. To explore the effect of fish intake, we compared two groups of Bantu villagers in Tanzania; one group live on the shores of Lake Nyasa and their diet includes large amounts of freshwater fish; the other group live in the nearby hills and have a vegetarian diet. METHODS: We carried out a cross-sectional study of 622 fish-consuming villagers and 686 vegetarian villagers. 618 (99.4%) and 645 (94.0%), respectively, agreed to take part. Anthropometric and self-reported medical history data were collected by one local physician and a medical assistant, who also measured blood pressure and took blood samples for measurement of plasma lipids. A dietary questionnaire was administered to 25 families (about 15% of the study population) in each village. FINDINGS: After adjustment for age, sex, and alcohol intake the fish-consuming group had lower mean blood pressure than the vegetarian group (123/72 vs 133/76 mm Hg, p < 0.001). The frequencies of definite and borderline hypertension (by WHO criteria) were lower in the fish-consuming than in the vegetarian group (2.8 vs 16.4%; 9.7 vs 22.3%, respectively). Plasma concentrations of total cholesterol (mean 3.53 [SD 1.04] vs 4.10 [1.04] mmol/L), triglycerides (0.92 [0.64] vs 1.31 [0.64] mmol/L), and lipoprotein(a) (201 [213] vs 321 [212] mg/L), were all lower (p < 0.0001) in the fish-consuming group than in the vegetarian group. The proportions of n-3 polyunsaturated fatty acids in plasma lipids were higher (p < 0.0001) in the fish-consuming group than in the vegetarian group (eicosapentaenoic acid 2.3 [1.3] vs 0.7 [0.2]%; docosapentaenoic acid 1.1 [0.4] vs 0.6 [0.3]%; docosahexaenoic acid 5.7 [1.6] vs 1.5 [1.1]%). INTERPRETATION: In these villagers, consumption of freshwater fish (300-600 g daily) was associated with raised plasma concentrations of n-3 polyunsaturated fatty acids, lower blood pressure, and lower plasma lipid concentrations.

Adult↗

Use of green fluorescent protein (GFP) to study the invasion pathways of Edwardsiella tarda in in vivo and in vitro fish models.

Edwardsiella tarda is a fish pathogen that causes systemic infections in many food and ornamental fish. E. tarda PPD130/91 and PPD125/87 were selected as representatives of the virulent and avirulent groups, respectively, from eight fish isolates, and transformed with plasmids encoding either green fluorescent protein (pGFPuv) or blue fluorescent protein (pBFP2). Two host models were used to study the invasion pathway of E. tarda in vitro and in vivo. Epithelioma papillosum of carp (EPC) was used as the first model. Virulent and avirulent E. tarda strains were found to adhere to and invade EPC cells. Interactions between E. tarda and host cells examined under confocal microscopy and intracellular growth were followed at different time points. Bacterial internalization of PPD130/91 and PPD125/87 involved microfilaments and protein tyrosine kinase since cytochalasin D (an inhibitor of microfilament polymerization) and genistein (an inhibitor of protein tyrosine kinase) prevented internalization. Confocal studies revealed co-localization of polymerized actin with bacteria. Staurosporine, a protein kinase C inhibitor, accelerated internalization of PPD125/87, whereas PD098059, a mitogen-activated protein kinase (MAPK) kinase inhibitor prevented internalization of PPD130/91. In the second model, blue gourami were infected with E. tarda intramuscularly. Mortalities were observed in PPD130/91(pGFPuv)-infected fish with high bacterial numbers detectable in all organs. PPD125/87(pBFP2)-infected fish did not die and the bacterial population decreased over time. Mixed infections comprised of both PPD130/91(pGFPuv) and PPD125/87(pBFP2), where inoculum size was similar to the single infections, caused mortalities in fish. High bacterial populations were noted only in the fish body muscle. The PPD125/87(pBFP2) population in the fish decreased after 5 d. The number of PPD130/91(pGFPuv) also decreased in the fish organs, except for continued high growth in the body muscle. Histology revealed necrosis of the tissue (body muscle and liver) and fluorescent bacteria in fish that were infected with PPD130/91(pGFPuv) but not with PPD125/87(pBFP2). This study showed that fluorescent proteins are a useful tool for investigating bacterial host cell infection, and information elucidated here sheds new light on the interactions between E. tarda and its hosts.

Actins↗

Distribution of mycobacteria in clinically healthy ornamental fish and their aquarium environment.

Some mycobacterial species (particularly Mycobacterium marinum) found in aquarium environments may cause chronic diseases in fish and cutaneous infections in humans, the so-called 'fish tank granuloma'. The presence and distribution of mycobacterial species in clinically healthy aquarium fish and their environment has not been adequately explored. The present study analysed the occurrence of mycobacteria in a decorative aquarium (Brno, South Moravia) and in five aquaria of a professional fish breeder (Bohumin, North Moravia). After Ziehl-Neelsen staining, acid-fast rods (AFR) were observed in six (14.3%) and mycobacteria were detected by culture in 18 (42.9%) of 42 tissue samples from 19 fish. Sixty-five samples of the aqueous environment from all six aquaria were examined; AFR were found in 16 (24.6%) and mycobacteria were detected by culture in 49 (75.4%) samples. Forty-one (70.7%) of 58 selected mycobacterial isolates were identified biochemically as follows: M. fortuitum, M. flavescens, M. chelonae, M. gordonae, M. terrae, M. triviale, M. diernhoferi, M. celatum, M. kansasii and M. intracellulare. The clinically important species for humans and fish, M. marinum, was not detected. Mycobacterium kansasii was isolated from one sample of the aquarium environment from North Moravia, which is a region of the Czech Republic with endemic incidence of M. kansasii in water. The incidence of other conditionally pathogenic mycobacterial species in healthy fish and in all investigated constituents of the aquarium environment including snails and crustaceans used for fish feeding, was quite high. Accordingly, mycobacterial species from aquarium environments may serve as a possible source of infection for both aquarium fish and immunodeficient fish handlers.

Animals↗

Fish intake may limit the increase in risk of coronary heart disease morbidity and mortality among heavy smokers. The Honolulu Heart Program.

BACKGROUND: Research has shown that fish consumption limits damage to the lungs caused by cigarette smoking, possibly by the effects of fish on arachidonic acid metabolism. We explored this fish-smoking interaction using coronary heart disease (CHD) incidence and mortality as the outcome. METHODS AND RESULTS: The Honolulu Heart Program began in 1965 to follow a cohort of 8006 Japanese-American men aged 45 to 65 years who lived on Oahu, Hawaii, in 1965. Fish intake was measured at baseline by use of a questionnaire. For current smokers at baseline (n = 3310) who reported low fish intake (< 2 times/wk), age-adjusted 23-year CHD mortality rates increased with the number of cigarettes smoked per day (2.3, 3.1, and 6.9 per 1000 person-years for men who smoked < 20, 20 to 30, and > 30 cigarettes/d, respectively; trend test P < .0001). Among current smokers whose fish intake was high (> or = 2 times/wk), CHD mortality rates showed no relation with cigarettes/d (3.7, 3.2, and 3.7 per 1000 person-years for the corresponding levels of smoking). A Cox proportional hazards model based on current smokers, adjusted for age, years in Japan, calories/d, alcohol intake, physical activity index, years smoked, hypertension, and serum cholesterol, blood glucose, and uric acid levels, was examined. In the high-smoking group, the risk factor-adjusted relative risk (RR) for CHD mortality among those with high fish intake was half that of those with low fish consumption (RR = 0.5, 95% confidence interval = 0.28 to 0.91). A Cox model that adjusted for similar risk factors confirmed a significant interaction of cigarettes/d and fish intake (P < .01) on CHD mortality. Analyses for CHD incidence showed similar results. CONCLUSIONS: Despite the findings of this investigation, the public health message for smokers continues to be to stop smoking. However, an interaction between fish intake and cigarette smoking is biologically plausible and deserves further investigation. The study of this phenomenon may shed light on the biological mechanisms by which cigarette smoking leads to CHD.

Aged↗

Feeding fish meal and extruded soybeans enhances the conjugated linoleic acid (CLA) content of milk.

Twelve multiparous Holstein cows averaging 65 (33 to 122) DIM were used in a 4 x 4 Latin square for 4-wk periods to determine whether feeding fish oil as fish meal would stimulate increased amounts of milk conjugated linoleic acid (cis-9, trans-11 C18:2; CLA) and transvaccenic acid (trans-11 C18:1; TVA) when the cows were fed extruded soybeans to supply additional linoleic acid. Treatment diets were 1) control; 2) 0.5% fish oil from fish meal; 3) 2.5% soybean oil from extruded soybeans; and 4) 0.5% fish oil from fish meal and 2% soybean oil from extruded soybeans. Diets were formulated to contain 18% crude protein and were composed (dry basis) of 50% concentrate mix, 25% corn silage, and 25% alfalfa hay. Intake of DM was not affected by diet. Milk production was increased by diets 2, 3, and 4 compared with diet 1 (control). Milk fat and milk protein percentages decreased with diets 3 and 4. Milk fat yield was not affected by treatments, but yield of milk protein was increased with supplemental fish meal and extruded soybeans or their blend. When diets 2, 3, or 4 were fed, concentrations of cis-9, trans-11 CLA in milk fat increased by 0.4-, 1.4-, and 3.2-fold, and TVA concentrations in milk fat increased by 0.4-, 1.8-, and 3.5-fold compared with the control milk fat. Increases in TVA and cis-9, trans-11 CLA were 91 to 109% greater when a blend of fish meal and extruded soybeans was fed than the additive effect of fish meal and extruded soybeans. This suggested that fish oil increased the production of CLA and TVA from other dietary sources of linoleic acid such as extruded soybeans.

Animal Feed↗

Advances in the knowledge of amphizoic amoebae infecting fish.

Free-living amoebae infecting freshwater and marine fish include those described thus far as agents of fish diseases, associated with other disease conditions and isolated from organs of asymptomatic fish. This survey is based on information from the literature as well as on our own data on strains isolated from freshwater and marine fish. Evidence is provided for diverse fish-infecting amphizoic amoebae. Recent progress in the understanding of the biology of Neoparamoeba spp., agents responsible for significant direct losses in Atlantic salmon and turbot industry, is presented. Specific requirements of diagnostic procedures detecting amoebic infections in fish and taxonomic criteria available for generic and species determination of amphizoic amoebae are analysed. The limits of morphological and non-morphological approaches in species determination are exemplified by Neoparamoeba, Vannella and Platyamoeba spp., which are the most common amoebae isolated from fish gills, Acanthamoeba and Naegleria spp. isolated from various organs of freshwater fish, and by other unique fish isolates of the genera Nuclearia, Thecamoeba and Filamoeba. Advances in molecular characterisation of SSU rRNA genes and phylogenetic analyses based on their sequences are summarised. Attention is particularly given to specific diagnostic tools for fish-infecting amphizoic amoebae and ways for their further development.

Animals↗

Triaenophorus nodulosus and T. crassus in fish from northern Finland.

10,288 fish specimens of 34 species from three water bodies in northern Finland were studied mainly in 1978-1982 Triaenophorus nodulosus and T. crassus parasites. Six of the 31 species from the Bothnian Bay were found to harbour T. nodulosus plerocercoids, four of the 11 from the cold, oligotrophic Lake Yli-Kitka in northeastern Finland and only one of the 6 from the small, eutrophic Lake Kuivasjärvi. The ruff (Gymnocephalus cernuus) was most essential intermediate host in the lakes, as supported by stomach analysis of predator fish. Although the highest prevalences were found in adult burbot (Lota lota) in two of the areas, these fish are more likely a blind end in the life cycle of T. nodulosus in the present case. T. crassus larvae were found only in three coregonid species and once in the intestine of a lamprey (Lampetra fluviatilis) from the sea. Neither the prevalence nor the intensity of infection in most of the intermediate fish hosts of T. nodulosus was seen to increase with the length of the fish. The only exception was the ruff in Lake Yli-Kitka, where a sharp increase was encountered. No prominent seasonal variation in Triaenophorus larvae infections was found in any of the cases. The prevalence of T. nodulosus infection in its final host, the pike (Esox lucius), was highest in the sea (93%) and lowest in the eutrophic lake (47%). Seasonally, the lowest T. nodulosus infections were found in June-July in the two lakes. A clear maturation cycle was also found, with the youngest worms in the summer months in all cases. T. crassus was found in every third pike in the sea and its proportion in relation to T. nodulosus is higher in the smallest and largest fish. In only 12%t of the pikes did the number of T. crassus exceed that of T. nodulosus, however, the mean ratio being 1:13 to favour of T. nodulosus. The results give an indication that the composition of the fish fauna in each water body has a considerable influence on the T. nodulosus burden and its distribution among its potential intermediate fish hosts. With the most stable environmental conditions and the greatest variety of fish species, the parasite burden in the Bothnian Bay is most evenly distributed among the 6 intermediate hosts. The fewer fish species occur in the water body, as in the present eutrophic lake, the more the significance of a few or even one intermediate host will increase.

Animals↗

Properties of iridoviruses from ornamental fish.

An iridovirus from 2 species of freshwater tropical imported fish was examined for its antigenic and biochemical properties and virulence for 3 species of food fish. The virus was found in both guppy (Poecilia reticulata) and doctor fish (Labroides dimidatus). The virus replicated in numerous fish cell lines including BF-2, CCO and EPC. Virus titers reached 10(8) TCID50/ml in each cell line. The virions had similar size and morphology to those previously reported to cause systemic infections among catfish in Europe and from redfin perch and rainbow trout in Australia. A comparison of the ornamental fish iridovirus with these systemic agents indicated that all share common antigens detected by indirect fluorescent antibody tests and Western blots. Additionally, polymerase chain reactions using primer sets developed for the red fin perch virus, amplified a segment of genomic DNA from the ornamental fish isolate. An examination of the virulence of the ornamental fish isolate for 2 important food fish species, rainbow trout (Oncorhynchus mykiss) and channel catfish (Ictalurus punctatus), indicated the former species was susceptible although mortality was low. Dead fish had significant lesions in the liver and kidney and had titers of virus greater than 10(8) TCID50/g. We speculate that these iridoviruses, first detected in Australia in redfin perch, are all related strains in the Ranavirus genus that may have reached these geographically distant sites by movements of ornamental fish.

Animals↗