Home About us Contact
|
Home About us Contact | ||
|
|
||
Control Fish (control + fish)
Selected AbstractsPhysiological effects in juvenile three-spined sticklebacks feeding on toxic cyanobacterium Nodularia spumigena -exposed zooplanktonJOURNAL OF FISH BIOLOGY, Issue 3 2008J.-P. Pääkkönen Feeding rate, growth and nutritional condition as well as nodularin concentration of juvenile three-spined sticklebacks Gasterosteus aculeatus were assessed in an experimental study where field-collected fish were given a diet of zooplankton fed with toxic Nodularia spumigena for 15 days. Food consumption was higher in N. spumigena bloom conditions compared with the cyanobacterium-free control, but despite this the growth rate of exposed fish did not improve. Control fish and fish fed N. spumigena -exposed zooplankton had higher RNA:DNA ratios and protein content than fish grown in cyanobacterial bloom conditions indicating good nutritional condition and recent growth of fish, whereas in bloom conditions metabolic transformation of nodularin to less toxic compounds may cause an energetic cost to the fish affecting the growth rate of the whole organism. Juvenile three-spined sticklebacks collected from the field contained higher concentrations of nodularin at the beginning of the experiment (mean 503·1 ,g kg,1). After 15 days, the lowest nodularin concentrations in fish were measured in the control treatment, suggesting that fish fed with non-toxic food are able to detoxify nodularin from their tissues more effectively than fish in continuing exposure. [source] Effects of 11-ketotestosterone on genital papilla morphology in the sex changing fish Lythrypnus dalliJOURNAL OF FISH BIOLOGY, Issue 2 2000S. L. Carisle Five days after implantation with 11-ketotestosterone (KT) female Lythrypnus dalli exhibited elevated urinary KT levels and male-like genital papilla morphology. Papilla length increased, width decreased, and length : width ratio increased. Control fish exhibited increases in papilla length, and length : width ratio on day 3, but not on day 5. Changes in the total area of the papilla were not statistically significant. It is suggested that KT mediates genital papilla morphology rapidly and thus may be a useful indicator of circulating KT in L. dalli. [source] Effects of dietary supplementation of alga Haematococcus pluvialis (Flotow), synthetic astaxanthin and ,-carotene on survival, growth, and pigment distribution of red devil, Cichlasoma citrinellum (Günther)AQUACULTURE RESEARCH, Issue 8 2009C-H Pan Abstract Dietary carotenoids of various types and concentration can affect the pigmentation efficiency in an ornamental fish red devil, Cichlasoma citrinellum. Astaxanthin (AX) containing alga Haematococcus pluvialis, a synthetic AX, and a synthetic ,-carotene (BC) were supplemented in formulated diets at two concentrations, 80 and 160 mg kg,1, resulting in six pigmented diets. Formulated diet without carotenoids supplementation served as a control. These diets were fed to the fish, for 8 weeks. Astaxanthin dominated in body carotenoids deposition. Dietary BC hardly had contribution to body AX. Control fish had much lower AX content in skin, fin and muscle than fish fed pigmented diets, but had equal AX content in liver, intestine and gonad as those fish. Dietary synthetic AX had equal efficiency in depositing AX in skin and fin as natural AX but higher efficiency in gonad than natural AX. Fish fed AX supplemented at 160 mg kg,1, either natural or synthetic AX, had higher AX content in skin than fish at 80 mg kg,1 but had equal AX content in fin as fish at 80 mg kg,1. Disregarding the treatment effects, the overall average AX content in tissue in descending order was gonad>fin,(intestine=skin)>liver>muscle. [source] Effects of radio-transmitter antenna length on swimming performance of juvenile rainbow troutECOLOGY OF FRESHWATER FISH, Issue 4 2004K. J. Murchie Abstract,,, Technological advances have lead to the production of micro radio-transmitters capable of being implanted in fish as small as c. 5 g. Although the actual tags are small, transmitters are equipped with long antennas that can increase drag and tangle in debris. We examined the effects of radio-transmitter antenna length on the swimming performance of juvenile rainbow trout, Oncorhynchus mykiss, (N = 156, mean mass = 34 g, mean fork length = 148 mm). Although we tested a variety of different antenna lengths up to a maximum of 300 mm, only the longest antenna significantly impaired swimming performance relative to control fish (P < 0.001). There was no difference in swimming performance between the sham (surgery, but no transmitter) and the control fish (handled, but no surgery), suggesting that the surgical procedure itself did not negatively affect the fish. Regression analysis, however, indicated that there was a significant decrease in swimming performance associated with increased antenna length (R2 = 0.11, P < 0.001). In addition, when held in laboratory tanks, fish with the three longest antennas (150, 225 and 300 mm) frequently became entangled with the standpipe. We suggest that researchers, under the guidance of the tag manufacturer, trim antennas to the shortest possible length required to detect fish in their specific study area. Antenna length is clearly an important issue for small fish, especially for species that inhabit complex habitats where antennas may become entangled, and where fish must attain speeds near limits of their swimming capacity. Resumen 1. Los avances tecnológicos han llevado a producir micro radio-trasmisores capaces de ser implantados en peces de muy pequeño tamaño (,5 g). Aunque las marcas actuales son pequeñas, los trasmisores están equipados con antenas largas que pueden llegar a enredarse en los restos de vegetación. Examinamos los efectos de la longitud de la antena sobre la rutina natatoria de juveniles de Oncorhynchus mykiss (n = 156, peso medio = 34 g, longitud furcal media = 148 mm). 2. Aunque analizamos varias longitudes de antena, hasta 300 mm, solamente las de mayor longitud alteraron la rutina natatoria en relación a los peces control (P < 0.001). No hubo diferencia en la rutina natatoria entre individuos bajo cirugía pero sin trasmisores respecto de los individuos control (manipulados pero sin cirugía) lo que sugiere que los procedimientos de cirugía no afectaron negativamente a los peces. Sin embargo, análisis de regresión indicaron un declive significativo en la rutina natatoria asociado a la longitud de la antena (R2 = 0.11, P < 0.001). Además, al ser mantenidos en tanques, los individuos con las tres antenas mas largas (150, 225, y 300 mm) frecuentemente se enredaron con las tuberías. 3. Sugerimos a los investigadores que, bajo la dirección de los productores de marcas y antenas, consideren el uso de las antenas más pequeñas que permitan detectar a los peces en sus respectivas áreas de estudio. La longitud de la antena es una cuestión importante para los pequeños peces, especialmente para especies en hábitats complejos donde las antenas pueden llegar a enredarse y donde los peces pueden alcanzar velocidades casi al limite de su capacidad natatoria. [source] Levels of transaminases, alkaline phosphatase, and protein in tissues of Clarias gariepienus fingerlings exposed to sublethal concentrations of cadmium chlorideENVIRONMENTAL TOXICOLOGY, Issue 6 2008Babu Velmurugan Abstract The freshwater fish, Clarias gariepienus fingerlings, were exposed to sublethal concentrations (1.7 and 3.4 mg/L) of cadmium chloride for 12 days. Aspartate aminotransferase (AAT), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and total protein levels were assayed in the gill, brain, and muscle of the fish at regular intervals of 6 and 12 days. The activities of AAT, ALT, and ALP of the treated fishes increased significantly in all the tissues compared with the control fish. Protein level in all the tissues showed a significant decrease in comparison to unexposed controls throughout the experimental periods. These results revealed that cadmium chloride effects the intermediary metabolism of C. gariepienus fingerlings and that the assayed enzymes can work as good biomarkers of contamination. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2008. [source] Altered gene expression in the brain and ovaries of zebrafish (Danio Rerio) exposed to the aromatase inhibitor fadrozole: Microarray analysis and hypothesis generation,,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 8 2009Daniel L. Villeneuve Abstract As part of a research effort examining system-wide responses of the hypothalamic-pituitary-gonadal (HPG) axis in fish to endocrine-active chemicals (EACs) with different modes of action, zebrafish (Danio rerio) were exposed to 25 or 100 ,g/L of the aromatase inhibitor fadrozole for 24, 48, or 96 h. Global transcriptional response in brain and ovarian tissue of fish exposed to 25 ,g/L of fadrozole was compared to that in control fish using a commercially available, 22,000-gene oligonucleotide microarray. Transcripts altered in brain were functionally linked to differentiation, development, DNA replication, and cell cycle. Additionally, multiple genes associated with the one-carbon pool by folate pathway (KEGG 00670) were significantly up-regulated. Transcripts altered in ovary were functionally linked to cell-cell adhesion, extracellular matrix, vasculogenesis, and development. Promoter motif analysis identified GATA-binding factor 2, Ikaros 2, alcohol dehydrogenase gene regulator 1, myoblast-determining factor, and several heat shock factors as being associated with coexpressed gene clusters that were differentially expressed following exposure to fadrozole. Based on the transcriptional changes observed, it was hypothesized that fadrozole elicits neurodegenerative stress in brain tissue and that fish cope with this stress through proliferation of radial glial cells. Additionally, it was hypothesized that changes of gene expression in the ovary of fadrozole-exposed zebrafish reflect disruption of oocyte maturation and ovulation because of impaired vitellogenesis. These hypotheses and others derived from the microarray results provide a foundation for future studies aimed at understanding responses of the HPG axis to EACs and other chemical stressors. [source] Toxicity of fluoroquinolone antibiotics to aquatic organismsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2005April A. Robinson Abstract Toxicity tests were performed with seven fluoroquinolone antibiotics, ciprofloxacin, lomefloxacin, ofloxacin, levofloxacin, clinafloxacin, enrofloxacin, and flumequine, on five aquatic organisms. Overall toxicity values ranged from 7.9 to 23,000 ,g/L. The cyanobacterium Microcystis aeruginosa was the most sensitive organism (5-d growth and reproduction, effective concentrations [EC50s] ranging from 7.9 to 1,960 ,g/L and a median of 49 ,g/L), followed by duckweed (Lemna minor, 7-d reproduction, EC50 values ranged from 53 to 2,470 ,g/L with a median of 106 ,g/L) and the green alga Pseudokirchneriella subcapitata (3-d growth and reproduction, EC50 values ranged from 1,100 to 22,700 ,g/L with a median 7,400 ,g/L). Results from tests with the crustacean Daphnia magna (48-h survival) and fathead minnow (Pimephales promelas, 7-d early life stage survival and growth) showed limited toxicity with no-observed-effect concentrations at or near 10 mg/L. Fish dry weights obtained in the ciprofloxacin, levofloxacin, and ofloxacin treatments (10 mg/L) were significantly higher than in control fish. The hazard of adverse effects occurring to the tested organisms in the environment was quantified by using hazard quotients. An estimated environmental concentration of 1 ,g/L was chosen based on measured environmental concentrations previously reported in surface water; at this level, only M. aeruginosa may be at risk in surface water. However, the selective toxicity of these compounds may have implications for aquatic community structure. [source] Mortality associated with catch and release of striped bass in the Hudson RiverFISHERIES MANAGEMENT & ECOLOGY, Issue 5 2003M. J. Millard Abstract Catch-and-release fishing has increased in many fisheries, but its contribution to fishing mortality is rarely estimated. This study estimated catch and release mortality rates of striped bass, Morone saxatilis (Walbaum), for the spring recreational fishery in the Hudson River. Treatment fish (caught with live bait on spinning gear) and control fish (captured by electric fishing) were placed in in situ holding pens for 5 days. Mortality rates were estimated using conditional instantaneous mortality rates and additive finite mortality rates. Influences of variables (playing and handling time, hook location, degree of bleeding and fish length) on hooking mortality rates were examined by logistic regression. Conditional instantaneous mortality rates and additive finite mortality rates were 31 and 28%, respectively. Hook location significantly affected the survival of striped bass. Angling catch, effort, and release rates must be integrated with associated hooking mortality rates before this component of overall population mortality can be incorporated into management decisions. [source] Effects of catch and release angling on Atlantic salmon, Salmo salar L., of the Conne River, NewfoundlandFISHERIES MANAGEMENT & ECOLOGY, Issue 3 2002J. B. DEMPSON The effects of catch and release angling on survival of Atlantic salmon, Salmo salar L., at Conne River, Newfoundland, were investigated by retaining angled (n=49; experimental group) and trap-caught (n=20; control group) fish in holding cages for up to 40 days. Samples were obtained from 8 June to 4 July, 2000, and partitioned among four water temperature strata. Apart from not being angled, control fish were handled, tagged, and transferred to holding cages in a manner similar to angled salmon. Water temperatures and discharge were monitored throughout the duration of the study. Overall, 8.2% of salmon caught and released died, but 12% died among salmon angled in water temperatures , 17.9 °C. No control fish died. There were no significant differences in time associated with angling, exposure to air, tagging, transfer to holding cages, nor total handling time between salmon that survived vs. those that died. Results of the study should encourage managers to continue to use catch and release as a viable tool in the management of Atlantic salmon stocks. [source] Growth-enhanced fish can be competitive in the wildFUNCTIONAL ECOLOGY, Issue 5 2001J. I. Johnsson Summary 1,The widespread commercial interest in producing growth-enhanced organisms has raised concerns about ecological consequences, emphasizing the need to understand the costs and benefits associated with accelerated growth in nature. Here, sustained-release growth hormone (GH) implants were used to estimate the competitive ability of growth-enhanced fish in the wild. Growth rate, movements and survival over winter were compared between GH-implanted and control Brown Trout in a natural stream. The study was repeated over two consecutive years. 2,GH treatment had no effect on recapture rates, indicating that mortality rates did not differ between GH-treated and control fish. More GH-treated trout (63%) than control fish (41%) were recaptured within their 10 m section of release. Thus, GH-treated fish were more stationary than control fish over winter. 3,GH-treated fish grew about 20% faster than control fish. This was mainly because of a three-fold growth rate increase in GH-treated fish in late summer, whereas growth rates over winter did not differ significantly between treatment groups. These results were consistent over both replicate years. 4,This first study of growth-enhanced fish in the wild shows that they can survive well and therefore may out-compete normal fish with lower growth rates. Although selection against rapid growth may be more intense at other life-history stages and/or during periods of extreme climate conditions, our findings raise concerns that released or escaped growth-enhanced salmonids may compete successfully with resident fish. It is clear that the potential ecological risks associated with growth-enhanced fish should not be ignored. [source] Testing the assumptions of the ideal despotic distribution with an unpredictable food supply: experiments in juvenile salmonJOURNAL OF ANIMAL ECOLOGY, Issue 2 2005AMANDA MACLEAN Summary 1Models linking the behaviours of individual animals, their positions within socially complex groups and spatio-temporal variation in resource distribution offer a promising base for predicting population responses to changing environments. The ideal free and despotic distributions and their derivatives are particularly influential in this regard. 2Due to the difficulties of conducting work in the wild, for some groups of animals such models are often based on observations of animals in small-scale systems under conditions that are well controlled, but unnaturally simple. 3Using an experimental system based on field observations of home range size and variation in food availability, the present study tested whether models derived using small-scale laboratory observations are valid for juvenile Atlantic salmon in more natural conditions. 4Contrary to predictions, we found no differences in behaviour between the control fish (which experienced consistently rich feeding patches) and the experimental fish (which experienced unpredictable 10-fold changes in patch quality). 5Also contrary to predictions, in the variable condition, salmon used high quality patches (which were an order of magnitude better than low quality patches) only marginally (5%) more than would be expected if they were to forage at random. There was significant variation in foraging strategies between individual fish, with 28% of the population making non-random use of foraging patches. 6The only apparent systematic relationship between social rank and use of foraging patches was that fish that were both dominant and made many moves between feeding locations tended to leave rich patches less frequently than they left poor patches. 7Despite the low correlation between patch quality and movement, there was substantial movement of fish among patches. Forty-four per cent of moves followed aggressive interactions and most others were spontaneous, with no obvious motivating factor apparent. 8The study exposes a discrepancy between expectations derived from the basic concepts of patch choice theory and the behaviour of Atlantic salmon in the conditions pertaining in the present study. 9It is suggested that this discrepancy may arise both from the fact that applicability of patch choice models may be very sensitive to the stability of differences in patch quality and from uncertainties about the costs of habitat sampling. [source] Effect of short term exposure to the anaesthetic 2-phenoxyethanol on plasma osmolality of juvenile dusky kob, Argyrosomus japonicus (Sciaenidae)JOURNAL OF APPLIED ICHTHYOLOGY, Issue 3 2008A. K. Bernatzeder Summary The plasma osmolality of early juvenile dusky kob, Argyrosomus japonicus, exposed to 2-phenoxyethanol and control fish that were pithed prior to sampling, was investigated. Exposure to 2-phenoxyethanol, after 2, 4, 6, 8 and 10 min, did not alter plasma osmolality (Friedman test; P = 0.976). There was no significant relationship between the size of fish within the range 133,170 mm SL (40,85 g) and plasma osmolality. Finally, there was no significant difference in plasma osmolality between anaesthetized fish and the control group that were pithed directly after removal from the tanks. Anaesthetizing juvenile dusky kob with 2-phenoxyethanol prior to blood sampling did not affect plasma osmolality. [source] Nutritional evaluation of various plant protein sources in diets for Asian sea bass Lates calcariferJOURNAL OF APPLIED ICHTHYOLOGY, Issue 2 2000By P. S. Eusebio A biological assay was conducted to evaluate the suitability of various leguminous seed meals and leaf meals as dietary protein sources for Asian sea bass, Lates calcarifer. In the growth experiment, fish (initial mean weight ±,standard error (SE) of 3.8 ± 0.5 g) were fed isonitrogenous and isocaloric diets containing test ingredients to replace 13,18% of the diet. The same diet formulations were used in a digestibility experiment, except that 1% Cr2O3 was added as an external indicator. The growth of the control fish was comparable to fish fed leguminous seed meal-based diets, and better than those given leaf meal-based diets. The control diet had the highest apparent protein digestibility (APD) value. No significant differences were observed between the APD of white cowpea (Vigna unguiculata), green mungbean (V. radiata) and papaya (Carica papaya) leaf meal-based diets. However, the cassava (Manihot esculenta) leaf meal-based diet had the lowest APD value. The present findings suggest that white cowpea and green mungbean meals can be used as protein sources in practical diets to replace 18% of the sea bass diet without affecting their growth. [source] Rapid bioconcentration of steroids in the plasma of three-spined stickleback Gasterosteus aculeatus exposed to waterborne testosterone and 17,-oestradiolJOURNAL OF FISH BIOLOGY, Issue 3 2007R. J. Maunder The relationship over time between the concentrations of two steroids, singly and in combination, in a static exposure system and in the blood of three-spined stickleback Gasterosteus aculeatus, held within the exposure system was investigated. Groups of three-spined stickleback were exposed (nominally) to either 1000 ng l,1 17,-oestradiol (E2), testosterone (T) or E2 and T in combination at the same concentrations for 6 days. Both water and fish were sampled at intervals and steroid concentrations in both compartments were determined. The plasma steroid time profile revealed a rapid bioconcentration within the first 6 h of exposure. The plasma steroid levels attained at this time point (20,90 ng ml,1) were up to 50-fold (E2) and 200-fold (T) greater than the actual levels of steroid measured in the exposure water, while levels in the blood of control fish did not exceed 4 ng ml,1. The substantial elevation of plasma steroid levels relative to the concentrations of steroid to which the fish were exposed in the ambient water gives scope for delivery of the steroids to target endocrine tissues at levels far in excess of what might be predicted on the basis of passive branchial uptake alone. These results are discussed in relation to endocrine disruption, and in particular the occurrence of effects in fish exposed to levels of endocrine active substances that are seemingly physiologically irrelevant. [source] Ultrastructural study of skin and eye of UV-B irradiated ayu Plecoglossus altivelisJOURNAL OF FISH BIOLOGY, Issue 6 2005J. G. Sharma A scanning electron microscopic study of the skin and eye of UV-B radiated ayu Plecoglossus altivelis(age 30 days, mean ± s.e. total length: 16·25 ± 0·11 mm) under laboratory condition showed marked changes when compared with the control fish without UV-B radiation. The exposure of the fish to the radiation resulted in the destruction of microridges in the epidermis and exposed neuromast cells of the skin. Domed protrusions were also more common in the skin of UV-B radiated fish than in the control fish. The appearance of mucus in both groups was different. In the control skin the mucus was spread over a wide area whereas in the treated fish the mucus was concentrated in a small area. The anastomozing structures of the microridges of the eyes were lost in UV-B radiated fish and the microridges themselves were fewer in number, fragmented, and aggregated. Mucus cells, prominently visible in the control fish, were distorted in the treated fish. Cell contours were irregular in UV-B radiated fish and cell to cell contacts had been lost in this group. [source] Effect of cycles of feed deprivation on growth and food consumption of immature three-spined sticklebacks and European minnowsJOURNAL OF FISH BIOLOGY, Issue 1 2003L. Wu Individual juvenile three-spined sticklebacks Gasterosteus aculeatus and European minnow Phoxinus phoxinus, from sympatric populations, were subjected to four cycles of 1 week of food deprivation and 2 weeks of ad libitum feeding. Mean specific growth rate during the weeks of deprivation was negative and did not differ between species. The three-spined stickleback showed sufficient growth compensation to recover to the growth trajectory shown by control fish daily fed ad libitum. The compensation was generated by hyperphagia during the re-feeding periods, and in the last two periods of re-feeding, the gross growth efficiencies of deprived three-spined sticklebacks were greater than in control fish. The expression of the compensatory changes in growth and food consumption became clearer over the successive periods of re-feeding. The European minnow developed only a weak compensatory growth response and the mass trajectory of the deprived fish deviated more and more from the control trajectory. During re-feeding periods, there were no significant differences in food consumption or gross growth efficiency between control and deprived European minnows. The differences between the two species are discussed in terms of the possible costs of compensatory growth, the control of growth and differences in feeding biology. [source] Susceptibility of channel catfish, Ictalurus punctatus (Rafinesque), to Edwardsiella ictaluri challenge following copper sulphate exposureJOURNAL OF FISH DISEASES, Issue 10 2007B R Griffin Abstract Channel catfish, Ictalurus punctatus (Rafinesque), with or without a preliminary 24 h exposure to 2 mg copper sulphate L,1, were challenged with 7.5 × 106 colony forming units L,1 of Edwardsiella ictaluri to determine the effect of copper sulphate on disease resistance. Catfish previously exposed to copper sulphate were significantly more resistant to the bacterial challenge than those not exposed. Catfish not exposed to copper sulphate suffered 35.5% mortality while catfish exposed to copper sulphate experienced 14.1% mortality. Copper concentrations were the same in tank waters of both exposed and control fish at the time of challenge, eliminating the possibility that copper in the water may have been toxic to bacteria. Copper concentrations in freeze dried and ground tissues of unexposed, exposed, and purged channel catfish were highest in fish before copper sulphate exposures suggesting that elevated tissue levels of copper were not responsible for the increased resistance to bacterial challenge. Competition for sites of bacterial attachment to gill or epithelial cells may account for the reduction in mortality; although this is not supported by the low copper content of fish tissue after copper exposure. [source] Protection against atypical furunculosis in Atlantic halibut, Hippoglossus hippoglossus (L.); comparison of a commercial furunculosis vaccine and an autogenous vaccineJOURNAL OF FISH DISEASES, Issue 6 2003S Gudmundsdóttir Abstract Atlantic halibut, Hippoglossus hippoglossus (L.), was shown to be sensitive to infection by three different isolates of Aeromonas salmonicida ssp. achromogenes in pre-challenge tests using intraperitoneal (i.p.) and intramuscular (i.m.) injections as well as bath challenges. A commercial furunculosis vaccine, Alphaject 1200, and an autogenous vaccine, AAS, based on the challenge strain, induced immune protection as shown in challenge tests 8 weeks post-immunization. The survival rate of vaccinated fish after i.p. challenge was 100%, whereas mortality of control fish was 61%. Employing i.m. challenge, relative percentage survival induced by the furunculosis vaccine and the AAS vaccine was 47 and 44, respectively. Mortality of i.m. injected controls was 68%. Vaccinated fish behaved normally following vaccination but the weight gain was significantly reduced in vaccinated fish 8 weeks post-vaccination compared with control fish receiving phosphate-buffered saline. At the same time, intra-abdominal adhesions were observed in fish injected with either of the two vaccines or adjuvant alone. Antibody response against A. salmonicida ssp. achromogenes was detected in sera from fish receiving either vaccine. [source] Vaccination trials of sea bass, Dicentrarchus labrax (L.), against Photobacterium damsela subsp. piscicida, using novel vaccine mixturesJOURNAL OF FISH DISEASES, Issue 2 2003V Bakopoulos Abstract Bacterial cells of the marine fish pathogen Photobacterium damsela subsp. piscicida were grown in novel culture media. A mixture of whole cells and extracellular components was inactivated and used in bath, intraperitoneal (i.p.) and oral vaccination of sea bass, Dicentrarchus labrax, employing two sizes of fish. A commercial vaccine was used for comparative purposes. Control and immunized fish were either bath or intraperitoneally challenged 6 and 12 weeks post-vaccination. Small fish had significantly higher relative percentage survival with the novel vaccine mixture both at 6 and 12 weeks post-vaccination by bath, in comparison with the commercial vaccine. No protection was afforded at 6 or 12 weeks post-immunization by either vaccine after challenge via i.p. injection. Sea bass (1.5,2 g) intraperitoneally vaccinated with various adjuvanted vaccine mixtures were not protected against pasteurellosis. In contrast, larger sea bass (20 g) benefited from vaccination with the novel vaccine mixtures. Intraperitoneal challenge with the pathogen resulted in protection in both fish groups vaccinated with novel vaccine mixtures, whereas control fish suffered high mortalities (>80%). Orally vaccinated fish were immersion challenged with the pathogen. At 6 and 12 weeks post-vaccination the control fish had a high mortality and the fish vaccinated with the novel vaccine mixture achieved good protection. [source] The duration of efficacy following oral treatment with emamectin benzoate against infestations of sea lice, Lepeophtheirus salmonis (Krøyer), in Atlantic salmon Salmo salar L.JOURNAL OF FISH DISEASES, Issue 3 2000J Stone The duration of efficacy of emamectin benzoate in the oral treatment of sea lice, Lepeophtheirus salmonis, infesting Atlantic salmon, Salmo salar L., was evaluated in a tank study. One group of salmon was treated at a nominal dose of 50 ,g kg,1 biomass day,1 for 7 consecutive days and a second group was untreated. Fish were then redistributed to 16 tanks, each holding 17 control and 17 treated fish. On days 34, 41, 48, 55, 62, 69, 76 and 83, two tanks were challenged with L. salmonis copepodites. Eight to 14 days after each challenge, fish were anaesthetized and numbers of lice recorded. Treatment with emamectin benzoate prevented development of copepodites for up to 62 days from the start of treatment, and chalimus numbers remained low for 69 days. Treated fish, challenged from days 34 to 69, had significantly (P<0.01) fewer lice than control fish. Treated fish challenged at days 76 and 83 still had fewer lice than control groups, although differences were not statistically significant for both replicates. When chalimus appeared on treated fish challenged at days 69,83, survival of chalimus to adult stages was lower than on control fish. Louse egg production on treated fish challenged at days 62,83 was not reduced compared to control groups. [source] Correlated changes in skeletal muscle connective tissue and flesh texture during starvation and re-feeding in brown trout (Salmo trutta) reared in seawaterJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 11 2004Jérôme Bugeon Abstract Quantitative and qualitative changes to muscle and collagen were analysed following starvation and re-feeding of brown trout (Salmo trutta) reared in seawater. Fish were submitted to starvation for 2 months followed by re-feeding for 1 month and compared with a control group continuously fed. Classical effects of starvation on growth and morphometrics traits were observed with only a partial recovery of these parameters after 1 month of re-feeding. Muscle composition of starved fish was significantly affected (lower dry matter content and higher post-mortem pH) compared with control fish and was partially recovered in re-fed fish compared with continuously fed fish. Muscle structure and composition were affected with thinner muscle fibre and higher connective tissue content for the starved fish but similar thickness of myosepta compared with the control group. No difference was observed after 1 month of re-feeding. Characteristics of the connective tissue were significantly affected by starvation (more high weight molecular collagen form, higher thermal stability of skin collagen). These differences remained significant after the re-feeding period. Starved fish showed also higher mechanical resistance of the raw flesh compared with the control group, but no difference in rheological measurements was observed after 1 month of re-feeding. The changes in texture and their relationships with muscle composition, muscle structure and collagen characteristics are discussed. Copyright © 2004 Society of Chemical Industry [source] Application of Compensatory Growth to Enhance Production in Channel Catfish Ictalurus punctatusJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 3 2001Nagaraj G. Chatakondi Four treatment groups that received repeating cycles of fixed feed deprivation for either 0, 1, 2, or 3 d (control, treatment 1, treatment 2, and treatment 3, respectively), followed by periods of refeeding with a 36% protein commercial catfish feed once daily as long as the active phase of compensatory growth (CG) persisted, were assessed in flow-through aquaria. No-feed periods elicited the CG state and were immediately followed by days of ad libatum refeeding. At the end of 10 wk, average growth rate (AGR) of fish was higher (P < 0.05) than the control by 40%, 180%, and 191% for treatment 1, treatment 2, and treatment 3, respectively. The average weight of fish in treatment 3 was heavier (P < 0.05) than the average control group at the end of the study period. Mean daily feed consumption was 3.91%, 5.03%, 5.36%, and 5.98% for control, treatment 1, treatment 2, and treatment 3, respectively. Mean feed consumption per fish per day was 24%, 71.3%, and 70.7% higher than the control in treatment 1, treatment 2, and treatment 3, respectively. Restricted feeding is one of the effective methods to contain ESC-related losses in commercial channel catfish fingerling operations. The mean cumulative survival of treatment groups registered higher (P < 0.05) survival to Edwardsiella ictaluri infection compared to the daily fed control fish. Results from this study show that compensatory growth response triggered by periodic non-feeding days can improve growth rate, feed consumption, and improved survival to ESC infections in channel catfish fingerlings. [source] The Relationship Between Vaccine Dose and Efficacy in Channel Catfish Ictalurus punctatus Vaccinated as Fry with a Live Attenuated Strain of Edwardsiella ictaluri (RE-33),JOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 2 2001David J. Wise Channel catfish Ictalurus punctatus were vaccinated at 12 d of age (post-hatch) by a 2-min bath immersion with attenuated Edwardsiella ictaluri RE-33 at doses of 2.5 × 105, 2.5 × 106, and 2.4 × 107 colony-forming units CFU/mL of water. Following vaccination, RE-33 was recovered from a greater percentage of fry that were vaccinated at the high and intermediate doses compared to fry vaccinated at the lowest dose. Independent of dose, the greatest percentage of RE-33 positive fry occurred between 1 and 6 d post-vaccination with a significant decrease in positive fry observed on day 12. A significant increase in mortality occurred 6 to 12 d post-vaccination in fry vaccinated at the highest dose. No differences in post-vaccination mortalities occurred between the other treatments. Following virulent E. ictaluri challenge, mortalities of fish vaccinated at doses of 2.5 × 106 and 2.4 × 107 CFU/mL were significantly less than those of fish vaccinated at 2.5 × 105 CFU/mL and sham-vaccinated control fish. These data show that vaccination with RE-33 can offer protection against subsequent virulent E. ictaluri infection. [source] Regulation of prostaglandin synthesis in ovaries of sexually-mature zebrafish (Danio rerio)MOLECULAR REPRODUCTION & DEVELOPMENT, Issue 11 2009Andrea L. Lister This study investigates the regulation of prostaglandin (PG) synthesis in the ovaries of sexually-mature zebrafish (Danio rerio). We examined the ovarian expression of genes within the arachidonic acid (AA) pathway, and the ovarian levels of 17,,20,-dihydroxy-4-pregnen-3-one (17,,20,-P), 17,-estradiol (E2), and PGF2, in spawning and nonspawning fish during the ovulatory cycle. Real-time RT-PCR analysis revealed that the expression levels of cytosolic phospholipase A2 (cpla2) and cyclooxygenases (COX)-2 (ptgs2) in ovarian fragments and in isolated full-grown follicles of spawning fish were highest at 6:00 when ovulation was expected to occur. In nonspawning fish, cpla2 expression levels declined over time while ptgs2 expression displayed the same temporal pattern as in spawning fish. Elevated levels of 17,,20,-P in the spawning fish occurred at 3:30, but there were no changes in the nonspawning fish. In other studies conducted to investigate the hormonal regulation of AA pathway genes, fish exposed via the water for 24 or 96,hr to 17,,20,-P or E2 exhibited reduced ovarian expression levels of COX-1 (ptgs1) and PG E synthase-2 (ptgsl), and E2 reduced the expression of cpla2. Injection of human chorionic gonadotropin (hCG) (100,IU) led to increased expression levels of cpla2 and ptgs2 at 2 and 18,hr post-treatment, but consistently reduced ptgs1 and ptgsl expression. In these fish, ovarian levels of 17,,20,-P were elevated at all time points and PGF2, levels in the hCG-treated group were significantly higher than the control fish at 18,hr. Collectively, these in vivo results suggest that gonadotropins and steroids are involved in the regulation of the AA pathway in ovarian follicles of zebrafish. Mol. Reprod. Dev. 76: 1064,1075, 2009. © 2009 Wiley-Liss, Inc. [source] O -acetylation of sialic acids in N -glycans of Atlantic salmon (Salmo salar) serum is altered by handling stressPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 14 2008Xin Liu Abstract O -acetylation is one of the major modifications of sialic acids that significantly alters biological properties of the parent molecule. These O -acetylated forms are components of the cellular membrane and can affect physiological and pathological responses. Understanding the role of N -glycans in physiology is of increasing relevance to cellular biologists in various disciplines who study glycoproteomics yet lack information regarding the function of the attached glycans. It is well known that stress may decrease immune function in fish; however, there are only few suitable biomarkers available to monitor the physiological responses under the stress conditions. This study is the first report on the effect of stress on the profile of O -acetylation of sialic acids in fish serum. In order to preserve the relevant structural characteristics as much as possible, native N -glycans were directly analyzed using CE-MS. We have characterized the N -glycans in serum of salmon (Salmo salar) exposed to long-term handling stress (15,s out of the water, daily for 4,wk) and compared with the results obtained from sera of control fish. The results indicated that major N -glycans in salmon serum contained mono-acetylated sialic acids (83%), and that the O -acetylation pattern of sialic acids could be altered by long-term stress. [source] Evaluation of the therapeutic effect of potassium permanganate at early stages of an experimental acute infection of Flavobacterium columnare in channel catfish, Ictalurus punctatus (Rafinesque)AQUACULTURE RESEARCH, Issue 10 2010Ahmed M Darwish Abstract The efficacy of potassium permanganate (KMnO4) against the early stages of an experimental acute infection of Flavobacterium columnare in channel catfish, Ictalurus punctatus, was evaluated. Fish were experimentally challenged by waterborne exposure for 2 h to F. columnare after cutaneous abrasion, and treated with KMnO4 at 2.0 mg L,1 above the KMnO4 demand at 0, 1, 2 or 4 h postchallenge for 24 h. Challenged non-treated fish acted as a positive control and non-challenged non-treated fish acted as a negative control. Fish challenged and treated with KMnO4 at 0, 1, 2 or 4 h postchallenge had mortalities of 26%, 63%, 64% and 83% respectively. The mortality of challenged fish treated with KMnO4 at 0 h postchallenge (26%) was significantly less than the positive control (77%). The mortalities of challenged fish treated at 1, 2 or 4 h postchallenge were not significantly different from the positive control fish. The results suggest that KMnO4 has a clear therapeutic value in early stages of columnaris infection but limited therapeutic value once the infection has progressed. [source] Modulation of the innate immune response of rohu Labeo rohita (Hamilton) by experimental freshwater lice Argulus siamensis (Wilson) infectionAQUACULTURE RESEARCH, Issue 9 2010Shailesh Saurabh Abstract The study was undertaken to determine the modulation in innate immune response of rohu (Labeo rohita) during experimental freshwater lice Argulus siamensis infection. Results showed that serum ,-2 macroglobulin (,-2M) activity, ceruloplasmin level and alternative complement activity were significantly (P<0.05) lower in fish at different degrees of lice infection in comparison with uninfected control. No significant difference (P>0.05) in haemagglutination titre was observed in fish with low- and high-degree lice infections as compared with uninfected control. The serum lysozyme level was significantly (P<0.05) lower in low degree of lice infection as compared with control fish. The total serum antiprotease, myeloperoxidase activity and total protein level were not significantly different (P>0.05) in different degrees of lice-infected fish with respect to the control fish. The study indicated that A. siamensis infection modulated the immune system of rohu by suppressing the ,-2M, serum complement activities and ceruloplasmin level and through induction of stress response. The baseline data obtained in the present study have tremendous importance in understanding the susceptibility of rohu to different degrees of parasitosis and might be useful in controlling this dreaded ectoparasitic infection in fish. [source] The antioxidant capacity response to hypoxia stress during transportation of characins (Hyphessobrycon callistus Boulenger) fed diets supplemented with carotenoidsAQUACULTURE RESEARCH, Issue 7 2010Chih-Hung Pan Abstract This study aimed to determine whether dietary carotenoid (CD) supplements could affect the antioxidant capacity of characins Hyphessobrycon callistus upon hypoxia stress at live transportation. Two types of CD [astaxanthin (AX), ,-carotene (BC)] and their 1:1 combination (MX) at three concentrations (10, 20 and 40 mg kg,1) were supplemented, resulting in nine CD diets. After 8 weeks' rearing, the resulting fish were divided into two subgroups and exposed to hypoxia or normoxia. Hypoxia involved a gradual decrease in dissolved oxygen (DO) from 6.5 to <1.0 mg L,1. Normoxia was DO kept in saturation. Hypoxia led to an increase in the total antioxidant status (TAS), superoxide dismutase (SOD), glutathione peroxidases (GPx) and aspartate aminotransferase (AST) activity of blood serum in fish, but had no effect on alanine aminotransferase (ALT). Under hypoxia, fish fed CD diets had lower SOD, GPx and ALT activity than control fish, showing that dietary CD could increase the antioxidant capacity and protection of the liver. Dietary AX was more effective for antioxidant capacity than BC and MX when under hypoxia stress, because GPx, ALT and AST were lower in AX-fed fish. Except TAS, the other four enzyme activities showed decreasing trends with increasing dietary CD concentrations. [source] LHRHa-induced ovulation of the endangered-Caspian brown trout (Salmo trutta caspius) and its effect on egg quality and two sex steroids: testosterone and 17,-hydroxyprogestroneAQUACULTURE RESEARCH, Issue 6 2010Ahmad Noori Abstract To induce synchronized ovulation, migrating wild Caspian brown trout (Salmo trutta caspius) females were treated with two interperitoneal injections of Des-Gly10, d -Ala6 LHRH (LHRHa), given 3 days apart. Two injections of 100 ,g kg,1 body weight of this hormone effectively induced ovulation. Within 27 days from the second injection, all fish injected with 100 ,g kg,1 LHRHa had ovulated compared with 54.5% of the controls. The mean time to ovulation was reduced significantly (P<0.05) from 31.67±4.84 days in control fish and 28.83±7.31 days in sham-treated fish to 16.36±1.61 days in fish injected with 100 ,g kg,1 LHRHa. The fertilization rate in 50 and 100 ,g kg,1 LHRHa-injected fish was significantly lower than that in the control fish (P<0.05). In fish injected with 50 and 100 ,g kg,1 LHRHa, significant (P<0.05) changes in testosterone (T) and 17,-hydroxyprogestrone (OHP) levels were observed. After the second LHRHa injection, the fish injected with 100 ,g kg,1 showed the highest serum levels of testosterone and OHP. These results demonstrate that the use of LHRHa can effectively reduce the mean time to ovulation and induce synchronized ovulation in Caspian brown trout. [source] Precocious sex change and spermatogenesis in the underyearling Malabar grouper Epinephelus malabaricus by androgen treatmentAQUACULTURE RESEARCH, Issue 2 2010Ryosuke Murata Abstract The Malabar grouper Epinephelus malabaricus is an important candidate species for commercial aquaculture in tropical and subtropical areas. In nature, this species requires more than 10 years to change sex from female to male and have active spermatogenic tissues in the testis. Thus, it is essential to find a means of producing sperm for seed production. This is the first report of artificial sex change in underyearling E. malabaricus. Female E. malabaricus with immature ovaries at 144 days post-hatch (DPH) were fed a diet with 17,-methyltestosterone (MT) at 50 ,g g,1 diet for 6 months. Sex change occurred in most of the treated fish, which had testis with all stages of spermatogenic germ cells including spermatozoa. In contrast, most of the control fish had immature ovaries. These results, which reveal that germ cells in the underyearling grouper have the ability to produce spermatozoa in response to exogenous androgen, demonstrate that sex change can be artificially induced during ovarian development. [source] | ||||||||||||||||