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PubMed2005

A comparative study on the parasite fauna of perch, Perca fluviatilis L., collected from a freshwater coastal lake, brackish-water Baltic Sea, and the interconnecting canal.

BACKGROUND: Parasitological surveys of freshwater fishes rarely include comparisons between two ecologically different bodies of water. Such studies might help to understand processes of establishment of parasite faunas in estuary areas. The results obtained could also provide useful tools for discriminating various fish populations based on the composition of their parasite faunas. The present authors attempted to study such data from Resko Lake-a freshwater coastal lagoon (6 km2 surface area), and the adjacent areas of the Baltic Sea. Resko Lake, located 12 km west of the city of Kołobrzeg, is shallow (1.5 m) and is connected to the sea through a small canal (1.3 km long, 30 m wide). MATERIAL AND METHODS: The material was collected from April 1969 and July 1970. A total of 159 perch were collected, in this number 104 fish from the lake, 43 from the sea, and 12 from the canal. RESULTS: A total of 32 parasite species were recovered from the fish necropsied. The parasites represented 7 higher taxa: Protozoa (3 species), Cestoda (4), Digenea (13), Nematoda (5), Acanthocephala (3), Mollusca (1), and Crustacea (3). The parasite fauna of perch from the sea was definitely more abundant (31 species) compared to that of the lake (21), and the canal (12 species). Infection parameters of 13 parasite species demonstrated significant differences between the locations studied. The infection level of 6 parasite species was significantly higher in perch from the sea: Bothriocephalus scorpii, Ligula sp., Brachyphallus crenatus, Camallanus truncatus, Hysterothylacium aduncum, and Echinorhynchus gadi. On the other hand, infection levels of 7 other species were higher at the lake: Triaenophorus nodulosus, Bucephalus polymorphus, Azygia lucii, Tylodelphys clavata, Camallanus lacustris, Acanthocephalus lucii, and Achtheres percarum. The infection parameters of the fish from canal were similar to those from the lake. Interesting observations were made on the seasonality of certain parasites of both lake- and Baltic perch. The presently observed differences between parasite faunas of the fish from ecologically different adjacent estuarine locations are certainly caused by diversified environmental conditions that affected the processes of formation of the parasite communities there. Among important factors that could affect compositions of the parasite faunas could have been: availability of the intermediate hosts, exchange of waters (Baltic water influxes to the lake), fish migrations (spawning), and finally the separate identity of the two fish stocks studied.

Animals↗
PubMed1995

Distribution of Myxobolus scleroperca (Myxobolidae: Myxosporea) in yellow perch (Perca flavescens) in the Great Lakes.

Myxobolus scleroperca infected the sclerotic cartilage of 26 of 100 yellow perch (Perca flavescens) examined in August-September 1991 from the Indiana waters of southern Lake Michigan. The mean lengths of infected and uninfected fish were 171 mm and 148 mm, respectively. A significantly higher percentage of female fish were infected than male because more larger females were examined than males. Perch less than 94 mm were not infected, indicating that the parasite is not evenly distributed in the host population, preferring larger (older) fish. An alternative explanation that should be considered is that young fish die from this infection. Yellow perch collected from eastern Lake Michigan in 1990 and from Saginaw Bay, Lake Huron in 1991 were not infected with M. scleroperca, indicating that the parasite has a patchy distribution among perch populations of the Great Lakes.

Age Factors↗
PubMed1998

The contributions of host age and size to the aggregated distribution of parasites in yellow perch, Perca flavescens, from Garner Lake, Alberta, Canada.

The independent effects of host age and size on parasite abundance are examined in yellow perch from Garner Lake in east-central Alberta. Older, larger perch tend to have more species of parasites combined with larger parasite infrapopulations. Sexual size dimorphism in perch generates 2 different size classes within each age class >2+ yr, thus allowing the opportunity to separate the effects of age and size on the recruitment of parasites by perch. The abundances of Diplostomum adamsi and Bothriocephalus sp. both increase with host age, whereas the increased abundances of Crepidostomum isostomum and Raphidascaris acus in larger fish are, in part, suggestive of size-specific feeding behaviors of the host. A combination of parasites with size- and age-dependent infrapopulations results in a size-dependent increase in infracommunity size. A comparison of variance-to-mean ratios within age classes to overall variance-to-mean ratios shows that the effects of host age and size on parasite recruitment do contribute to parasite aggregation.

Age Factors↗
PubMed1991

Trap perches to assess the activity of pyrethrins against the poultry red mite Dermanyssus gallinae in cage birds.

Trap perches were utilised to quantify mite recoveries during efficacy tests of pyrethrin formulations against experimental infestations of Dermanyssus gallinae (De Geer, 1778) in budgerigars and pigeons, and to monitor mite recoveries from untreated canaries. Pyrethrins applied topically before infestation significantly reduced the mean numbers of poultry red mites found in both budgerigar and pigeon trap perches, over those in untreated controls (P = less than 0.01). In untreated control budgerigars and pigeons, and in untreated canaries, the percentage recoveries after 48 h were 12.6 +/- 1.6, 4.1 +/- 1.9, and 32.6 +/- 1.6%, respectively (geometric mean +/- SD), and the blood engorgements rates were 71.5 +/- 1.7, 11.9 +/- 5.1, and 90.1 +/- 1.0% respectively. The recovery in trap perches of mites from canaries declined exponentially; 85% of the cumulative total recovered was collected 24 h after infestation, but small numbers were recovered daily up to 96 h (limit of observation). The use of the trap perches is discussed as a way of assessing the efficacy of acaricides, and as a laboratory tool in studies on mite aggregation behaviour or immune responses to mite infestation.

Administration, Topical↗
PubMed1983

The in vitro synthesis of final maturational steroids by ovaries of brook trout (Salvelinus fontinalis) and yellow perch (Perca flavescens).

The steroidogenic profile produced by ovaries of brook trout (Salvelinus fontinalis) and yellow perch (Perca flavescens) was examined using radioactive incorporation incubations. The radioactive metabolites produced were identified and were tested for their ability to induce germinal vesicle breakdown (GVBD) in oocytes in in vitro bioassays. Brook trout ovarian tissue converted [14C]progesterone to five metabolites that were effective in inducing GVBD in the bioassays: 5 beta-pregnanedione, 17 alpha-hydroxyprogesterone, deoxycorticosterone, and two more polar metabolites that were not identified. One of these two metabolites comigrated with 11-deoxycortisol and 17 alpha-hydroxy,20 beta-dihydroprogesterone (17 alpha, 20 beta prog) in thin layer chromatography. Androstenedione, testosterone, and estradiol-17 beta were also identified as metabolites of progesterone. Brook trout ovarian tissue did not extensively metabolize [14C]pregnenolone. Dehydroepiandrosterone and 17 alpha-hydroxypregnenolone were tentatively identified as metabolites of pregnenolone. Yellow perch ovarian tissue converted [14C]progesterone or [14C]pregnenolone to six metabolites that were effective in inducing GVBD in the bioassays: 5 alpha-pregnanedione, 17 alpha-hydroxyprogesterone, 20 alpha-dihydroprogesterone, 17 alpha-hydroxy, 20 alpha-dihydroprogesterone (tentatively identified), and two other unidentified metabolites. One of these two metabolites comigrated with 11-deoxycortisol and 17 alpha, 20 beta prog in thin layer chromatography. The only metabolite that induced ovulation of yellow perch oocytes in vitro was the metabolite comigrating with 11-deoxycortisol and 17 alpha, 20 beta prog. Androstenedione and testosterone were also identified as metabolites produced by yellow perch ovarian tissue. The results show that the ovaries of both species produce steroids that are active in the induction of oocyte final maturation.

Animals↗
PubMed1984

Biochemical and hematological studies on perch, Perca fluviatilis, from the cadmium-contaminated river Emån.

In a field investigation, biochemical and hematological parameters were measured in perch, Perca fluviatilis, living in the cadmium-contaminated river Emån in the southeast of Sweden. The number of lymphocytes was 45-100% higher in perch from the contaminated area than in the reference perch, indicating a stimulated immune defense. In addition, the cadmium-loaded fish suffered from a slight anemia and a disturbed carbohydrate metabolism and blood plasma ion composition. The observed effects suggest that cadmium affects fish in the environment similar to what has been observed in laboratory studied. However, the weaker response may imply that the perch in the field stimulation have been adapted and thus acquired an increased resistance to cadmium.

Animals↗
PubMed1992

Reproductive status, blood chemistry, gill histology and growth of perch (Perca fluviatilis) in three acidic lakes.

Perch (Perca fluviatilis L.) were sampled soon after spawning in three small acidic lakes (pH 4.3-6.1, Al(lab) 5-106 microg litre(-1), Ca2+ 0.01-0.08 mmol litre(-1)) and in one circumneutral lake (pH 5.9-6.4, Al(lab) 4-12 microg litre(-1), Ca2+ 0.06-0.07 mmol litre(-1)) in southern Finland. Due to the delayed spawning of perch in the acidic lakes, sampling in those lakes was performed later than in the reference lake. In spite of that, the gonadosomatic index (GSI) of males in all the acidic lakes was significantly greater than in the reference lake. Of the two lakes with similar low water pH, the effects on reproduction were more prominent in the lake with higher water Al content. The plasma Ca2+ concentrations of females in the acidic lakes were significantly smaller than in the females of the reference lake. The low female:male plasma Ca2+ ratio (1.0-1.32) depicted delay of spawning. Stress in perch in acidic water was also seen in elevated blood haematocrit values, especially in females. On the other hand, a low plasma Cl- level, a common response to acidic water in salmonids, was not detected in perch in the most acidic lakes. The amount of Al accumulated in the gill epithelium was highest in the most acidified lake with high Al concentration, but was also pronounced in a lake with low pH and low Al concentration.

Journal Article↗
PubMed2000

In vitro effect of gossypol acetate on yellow perch (Perca flavescens) spermatozoa.

Gossypol, a known antispermatogenic agent from the cotton plant genus Gossypium, was found to inhibit yellow perch sperm motility in vitro and lactate dehydrogenase activity in spermatozoa when used in a dose-dependent manner. This toxin also significantly decreased sperm fertilizing ability. Exposure of sperm suspension to a 200-µM concentration of gossypol caused sperm immobilization and a consequent lack of fertilization. Effects of gossypol on sperm motility and fertilizing ability were partially reversible when sperm suspensions were transferred to solutions without gossypol. This reversibility was proportional to the gossypol concentration. We observed a significant increase of abnormal embryos produced by the fertilization of spermatozoa pretreated with gossypol. This implies that gossypol could affect the sperm genome. The results indicate a usefulness for yellow perch sperm in studies of gossypol action mechanisms. Results of in vitro experiments suggest a potential for reproductive impairment in fish when using cottonseed-containing diets or organic fertilizers in yellow perch aquaculture. However, these observations should be confirmed in in vivo experiments with yellow perch and other species.

Journal Article↗
PubMed1993

Nesting, dust bathing and perching by laying hens in cages: effects of design on behaviour and welfare.

1. Laying hens (192 ISA Brown medium hybrids) were housed from 18 to 72 weeks as groups of 4 in conventional or experimental cages. The main area of all cages provided 675 cm2/hen. All experimental cages had perches, dust baths and nest boxes, which were of three types: litter (L), artificial turf (A) or plastic rollaway (P). These facilities provided an additional 375 to 480 cm2/hen. The nest boxes and dust baths occupied either high or low positions. Behaviour, physical condition and production of the birds were regularly recorded. 2. Mortality was low (1.6% overall) and egg production very good in all treatments. The proportion of cracked and dirty eggs was slightly (but not significantly) higher in the experimental cages. In the experimental cages 90% of eggs were laid overall in the nest boxes and 3% in the dust baths. The proportion laid in the nest boxes was lower early in the laying cycle and increased with time, reaching 99% in A. 3. The facilities were heavily used. Birds spent about 25% of day time on the perches and 10-15% in or near the nest box and dust bath. At night, the majority of birds (90 to 94%) roosted on perches, but most of the remainder were on the lips of the nest box or dust bath, fouling the interiors. 4. Pre-laying behaviour was much more settled in the experimental cages (45 min spent in the eventual laying position) than in the conventional ones (20 min) and total duration varied from 68 min in A to 87 min in P. The number of nest entries varied from 3.0 (A and P) to 4.3 (L); disturbance to sitting birds was correspondingly greater in L. 5. Dust bathing in the experimental cages generally took place during the afternoon in a single bout of about 5 min duration, whereas in the conventional cages it was brief and fragmented (3 bouts of 10 s each). The dust bath was also used for foraging behaviour (pecking and scratching). The treatments with small dust baths (A and P) caused problems for the birds. 6. Feather, foot and claw damage all tended to be less in the experimental than in the conventional cages, though only in the last case was the difference significant. Keel bone depressions appeared to be associated with perches; they were present in 43% of hens in the experimental cages but only 4% in conventional cages.(ABSTRACT TRUNCATED AT 400 WORDS)

Animal Welfare↗
PubMed2000

A note on the effects of perches and litter substrate on leg weakness in broiler chickens.

Two trials were conducted to investigate the effect of availability of perches on indices of leg weakness in broiler chickens. A third trial investigated the effect of litter substrate on similar indices of leg weakness in broiler chickens. Leg weakness traits examined were walking ability and tibial dyschondroplasia, tibial curvature, foot burn, and hock burn. Body weight was also measured in all trials. The presence of perches in the rearing pens had no effect on any of the indices of leg weakness examined in either trial. There were no consistent effects of perches on BW. Litter substrate significantly affected some indices of leg weakness; birds reared on wheat straw had poorer walking ability and more foot burn than birds reared on wood shavings, and birds reared on hemp waste were intermediate between them. There was no effect of litter substrate on tibial dyschondroplasia or tibial curvature. Turning the straw litter regularly and adding fresh supplies when necessary did not significantly improve indices of leg weakness. It was concluded that wood shavings provide a better litter substrate than straw, but that perches have no beneficial effect on reducing leg weakness in broilers.

Animals↗
PubMed2004

Measurement of an individual silver perch Bairdiella chrysoura sound pressure level in a field recording.

Simultaneous audio and video were recorded of a silver perch Bairdiella chrysoura producing its characteristic drumming sound in the field. The background noise contribution to the total sound pressure level is estimated using sounds that occurred between the pulses of the silver perch sound. This background contribution is subtracted from the total sound to give an estimate of the sound pressure level of the individual fish. A silver perch source level in the range 128-135 dB (re: 1 microPa) is obtained using an estimate of the distance between the fish and the hydrophone. The maximum distance at which an individual silver perch could be detected depends on the background sound level as well as the propagation losses. Under the conditions recorded in this study, the maximum detection distance would be 1-7 m from the hydrophone.

Air Sacs↗
PubMed2006

Molecular evidence for association of chlamydiales bacteria with epitheliocystis in leafy seadragon (Phycodurus eques), silver perch (Bidyanus bidyanus), and barramundi (Lates calcarifer).

Epitheliocystis in leafy seadragon (Phycodurus eques), silver perch (Bidyanus bidyanus), and barramundi (Lates calcarifer), previously associated with chlamydial bacterial infection using ultrastructural analysis, was further investigated by using molecular and immunocytochemical methods. Morphologically, all three species showed epitheliocystis cysts in the gills, and barramundi also showed lymphocystis cysts in the skin. From gill cysts of all three species and from skin cysts of barramundi 16S rRNA gene fragments were amplified by PCR and sequenced, which clustered by phylogenetic analysis together with other chlamydia-like organisms in the order Chlamydiales in a lineage separate from the family Chlamydiaceae. By using in situ RNA hybridization, 16S rRNA Chlamydiales-specific sequences were detected in gill cysts of silver perch and in gill and skin cysts of barramundi. By applying immunocytochemistry, chlamydial antigens (lipopolysaccharide and/or membrane protein) were detected in gill cysts of leafy seadragon and in gill and skin cysts of barramundi, but not in gill cysts of silver perch. In conclusion, this is the first time epitheliocystis agents of leafy seadragon, silver perch and barramundi have been undoubtedly identified as belonging to bacteria of the order Chlamydiales by molecular methods. In addition, the results suggested that lymphocystis cysts, known to be caused by iridovirus infection, could be coinfected with the epitheliocystis agent.

Animals↗
PubMed1989

Increase in bone strength of spent laying hens housed in modified cages with perches.

The strength of the tibia was compared in 72-week-old ISA brown hens housed as groups of four for 52 weeks either in conventional cages or in cages with a 450 mm long perch, positioned either at the front or the back of the cage. The breaking strength of the bone was measured by subjecting it to a gradually increasing force on a three-point rig until it broke. The median strength of the tibia was greater in birds from cages with either front (160 Newtons [N]) or rear perches (152 N) than from conventional cages (135 N). Increased between-bird variation in the cages with perches suggests that there is scope for a further increase in bone strength by the provision of perches long enough to accommodate all the birds simultaneously. These results show that the strength of the tibia can be increased almost as much by using new designs of cage as by housing hens on the floor.

Animals↗
PubMed2000

Induction of gynogenesis in muskellunge with irradiated sperm of yellow perch proves diploid muskellunge male homogamety.

Diploid gynogenesis was induced in muskellunge Esox masquinongy using UV-irradiated muskellunge sperm as the first step in producing monosex females. In this approach, we have to rely on negative controls as an indirect reference for sperm genetic material destruction. In the first experiment, equal proportions of gynogenetic females and males were produced. Negative controls, UV-irradiated sperm without heat shock, yielded some normal hatching larvae, described as spontaneous diploids. In the second experiment, muskellunge eggs were activated using sperm from yellow perch. Because hybrids between these species are not viable, we produced unambiguous gynogens. When UV-irradiated yellow perch sperm was used to inseminate muskellunge eggs, haploids resulted (22.5% +/- 2.8% survival to the eyed stage). To produce diploid gynogens, a heat shock of 31 degrees C was applied to inseminated eggs 20 min after activation for a duration of 6 min. This process yielded several hundreds of gynogens for rearing. Several treatments of masculinizing hormone, 17alpha-methyltestosterone (MT), were carried out. Fish were dissected and gonads examined histologically for sex determination. Gynogens produced using yellow-perch sperm confirmed the presence of males in the control group, whereas the MT bath treatment (400 microg/liter) resulted in the production of fish with ovotestis. These results provide evidence for male homogamety in muskellunge and imply that a change of strategy is needed to produce monosex populations.

Animals↗
PubMed2000

DNA adducts in perch (Perca fluviatilis) living in coastal water polluted with bleached pulp mill effluents.

DNA adducts were analyzed by (32)P-postlabeling in liver and intestine of perch (Perca fluviatilis). Fish were collected in the receiving water of a bleached kraft pulp mill at Norrsundet, Sweden, on the coast of the Bothnian Sea, and in three different reference areas. Sampling was carried out the last week in September 1993, 1995, and 1997. Since 1984/1985 the pulping process at Norrsundet has been successively modified and an external waste-water treatment has been installed, resulting in lowered and altered effluent discharges. Nevertheless, perch captured in the water area closest to the mill (2 km) had significantly elevated levels of aromatic/hydrophobic DNA adducts in both liver and intestine when compared to perch captured 8 km away and in the reference areas. Autoradiograms indicated a diagonal zone consisting of multiple overlapping adducts, a pattern typical of exposure to a complex mixture of aromatic/hydrophobic genotoxic substances. No significant difference in adduct levels was detected between the years. Results from this study reveal that fish in the area closest to the mill are exposed to substances with a genotoxic potential.

Animals↗
PubMed1999

Thyroid hormone regulation of perch ovarian 3beta-hydroxysteroid dehydrogenase/delta5-delta4-isomerase activity: involvement of a 52-kDa protein.

Ovarian follicles were collected from perch belonging to the prespawning (vitellogenic) stage and incubated in vitro for 5 h in the absence (control) and presence of 3, 5, 3'-triiodothyronine (T3). Addition of increasing concentrations of T3 from 12.5 to 100 ng/ml caused a linear increase of 3beta-hydroxysteroid dehydrogenase/delta5-delta4-isomerase (3 beta-HSD) activity to 50 ng and then it leveled off indicating a saturation of enzyme activity with 50 ng T3. T3 stimulation of 3beta-HSD activity could be blocked by cycloheximide indicating the involvement of T3-induced protein (TIP) isolated and purified earlier from this laboratory. Addition of fish TIP purified from perch ovarian follicle (fTIP) or rat granulosa cell TIP to ovarian follicular incubation at a dose of 5 microg/ml significantly increased (P < 0.01) 3beta-HSD activity. To observe whether TIP acts directly on the enzyme or not, 3beta-HSD from perch ovarian follicle was purified to homogeneity by the following steps: (i) Sephadex G 75 gel filtration, (ii) DEAE-Sephacel chromatography, and (iii) NAD-affinity column chromatography. Purified 3beta-HSD gave a clear single band on an SDS gel and its molecular weight is 45 kDa. Addition of fTIP to an assay mixture containing purified 3beta-HSD resulted in a fourfold increase of the enzyme activity. fTIP alone did not show enzyme activity when incubated with the radiolabeled substrate. Addition of T3 (50 ng) to the 3beta-HSD assay mixture had no effect on the enzyme activity. Determination of Vmax and Km of the purified enzyme in the absence (control) and presence of fTIP demonstrated a considerable increase of 3beta-HSD affinity and rate of enzyme reaction.

Animals↗
PubMed1997

Frequency distributions of fish parasites in the perch Perca fluviatilis L. from Lake Constance.

Seventy perch (Perca fluviatilis) caught in Lake Constance at Langenargen in May 1990 were examined for parasites. The frequency distributions of the eyefluke Diplostomum spathaceum (Rudolphi, 1819), and the tapeworms Proteocephalus percae (Müller, 1780) and Triaenophorus nodulosus (Pallas, 1781) fitted closely to a negative binomial. Only a few fish were highly parasitized. These fishes are devoured by the final hosts: gulls (Diplostomum spathaceum) or the pike (Triaenophorus nodulosus). The fish population was influenced negligibly and the parasite population stayed at a moderate level. During the spawning period female perch were infested with Proteocephalus percae more than the males. This may be because the females had a higher food consumption and became more infected by copepods (intermediate hosts). In contrast, Diplostomum spathaceum, Ichthyocotylurus variegatus, Triaenophorus nodulosus, and Tylodelphys clavata did not occur in different numbers in female and male perches. The frequency distribution of Ichthyocotylurus variegatus (Creplin, 1825) and Tylodelphys clavata (Nordmann, 1832) did not conform to a negative binomial.

Animals↗
PubMed2006

Pluripotency and chimera competence of an embryonic stem cell line from the sea perch (Lateolabrax japonicus).

A stable GFP-expressing (GFP(+)LJES1) cell strain was developed from the LJES1 cells obtained from sea perch (Lateolabrax japonicus,) embryos. GFP(+)LJES1 cells were induced in vitro by RA to differentiate into a variety of cell types and also had the ability to form embryoid body-like structures in suspension culture. To determine the differentiation potential of LJES1 cells in vivo, GFP(+)LJES1 cells were transplanted into sea perch and zebrafish embryos at mid-blastula stage. Twenty out of 478 transplanted sea perch embryos contained GFP-expressing LJES1 cells 24 h after microinjection. Fifteen chimera embryos developed into fry. In these chimeras, the GFP(+)LJES1 cells contributed to a variety of tissues including the head and trunk. In zebrafish, 221 embryos were microinjected with GFP(+)LJES1 cells and 22 chimera embryos and fries expressing GFP were obtained. Donor GFP(+)LJES1 cells contributed to various tissues in head and trunk of zebrafish embryos and hatched fry.

Animals↗