Proteocephalus ambloplitis and Contracaecum sp. from largemouth bass (Micropterus salmoides) stocked into Boundary Reservoir, Saskatchewan

Nonresident (introduced) largemouth bass (Micropterus salmoides) from Boundary Reservoir, Saskatchewan were examined for helminths. Four species of parasites were found (Diplostomum sp., Proteocephalus ambloplitis, Pomphorhynchus bulbocolli, and Contracaecum sp.). Contracaecum sp. larvae were absent in age-0 and age-1 bass, but prevalence and mean intensity increased with age for bass age-2 or older. Similarly, the prevalence and mean intensity of P. ambloplitis plerocercoids in bass were low until age-2; older bass harbored significantly more plerocercoids. Analysis of stomach contents indicates that this pattern of recruitment for Contracaecum sp. and P. ambloplitis is probably due to increased feeding by largemouth bass on aquatic insects and cannibalism after age-2, respectively. Although Contracaecum sp. may have been established in the reservoir prior to the introduction of bass, we are certain that P. ambloplitis was introduced via stocking with infected fingerlings.     

Occurrence of acanthocephalans in largemouth bass and smallmouth bass (Centrarchidae) from Gull Lake, Michigan

A total of 65 largemouth bass, Micropterus salmoides, and 27 smallmouth bass, M. dolomieu, collected in April-September 2000 and April-July 2001 from Gull Lake, Michigan, were examined for acanthocephalans. Leptorhynchoides thecatus and Neoechinorhynchus cylindratus infected all the bass examined. Leptorhynchoides thecatus had the highest mean intensity (258.2 +/- 185.4 in 2000 and 145.0 +/- 61.0 in 2001) of the species infecting smallmouth bass. Although N. cylindratus had higher mean intensities (42.1 +/- 37.9 in 2000 and 68.9 +/- 70.5 in 2001) than did L. thecatus in largemouth bass, the values were not significantly different between bass species. The prevalence, mean intensity, and mean abundance of Pomphorhynchus bulbocolli in the bass species were below the values for the other acanthocephalan species. Leptorhynchoides thecatus and N. cylindratus are the most abundant intestinal helminths in bass from Gull Lake.     

On some cestodes parasitizing freshwater fish in Italy.

The paper presents a systematic survey of some cestodes parasitizing freshwater fish in Italy. The following eight species were recorded: Monobothrium wageneri, Cyathocephalus truncatus, Triaenophorus nodulosus (plerocercoids and adults), Bothriocephalus acheilognathi, B. claviceps, Ligula intestinalis (plerocercoids), Schistocephalus sp. (plerocercoids) and Proteocephalus percae from Perca fluviatilis which is reported from freshwater fish in Italy for the first time. All the tapeworms recovered are described and figured.     

Lesion induction by the plerocercoid Lacistorhynchus tenuis (Cestoda) and wound healing in the striped bass Morone saxatilis (Walbaum)

San Francisco Bay-Delta striped bass, Morone saxatilis (Walbaum), form open lesions in response to a plerocercoid infection of Lacistorhynchus tenuis (Van Beneden, 1858) (Cestoda: Trypanorhyncha). Laboratory infection experiments showed that striped bass can be infected with the plerocercoids by ingesting infected copepods. Histological sections indicated that a cellular host response was mounted early in the infection period, and that despite the leucocytic infiltration the parasites continued to develop. However, at 3 months post-infection some of the plerocercoids began to degenerate, and lesions formed at this time and 14 months post-infection. Open lesions in adult striped bass collected from the field took 2 months to heal and were detectable for at least 22 months. Regeneration of the muscle tissue did not occur although the wound completely healed externally.     

Apolipoprotein A-I from striped bass (Morone saxatilis) demonstrates antibacterial activity in vitro

HDL and apolipoprotein A-I from teleostean fishes demonstrate in vitro activity against gram-positive and gram-negative bacteria. In this study, we purified ApoA-1 from striped bass (Morone saxatilis) plasma and examined its in vitro antibacterial activity against Streptococcus sp., Escherichia coli, and Mycobacterium marinum. In addition, we obtained sequence for a putative striped bass ApoA-1 gene, which when translated contained the identical sequence generated from N-terminal sequencing of the purified ApoA-1. The predicted secondary and tertiary structures contained the characteristic proline residues and high alpha-helical content conserved between mammals and fishes. Purified ApoA-1 exhibited antibacterial activity against the bacteria assayed. Concentrations of 125 microg/mL for E. coli, 250 microg/mL for Streptococcus sp., and 250 microg/mL for M. marinum, inhibited bacterial growth by 50% compared to control. ApoA-1 plasma concentrations in experimental and wild fish ranged from undetectable levels to greater than 5 mg/mL, indicating that striped bass ApoA-1 is an effective antibacterial agent at concentrations below the range of physiological concentrations in striped bass plasma. We therefore conclude that ApoA-1 could play a role in innate defense against bacterial pathogens in striped bass.     

西藏羊卓雍错高原裸鲤肠道寄生蠕虫的群落生态

为研究西藏羊卓雍错Yamdrok Lake高原裸鲤肠道寄生蠕虫的群落生态,探索寄生虫与西藏高原环境和独特的鱼类宿主三者之间的相互关系,以肠道寄生蠕虫为对象,于2020年7月对180尾高原裸鲤Gymnocypris waddellii [雌性120尾,雄性60尾,全长22.20—49.20 cm,平均全长(36.76±4.18) cm,体重77.3—896.7 g,平均体重(425.92±148.27) g]进行了剖检,对群落结构和种间关系等群落生态进行了分析。羊卓雍错高原裸鲤肠道寄生蠕虫群落由5个物种构成,分别为聂氏似短节绦虫Parabreviscolex niepini、对盲囊线虫Contracaecum eudyptulae、束首线虫未定种Streptocara sp.、新棘吻虫未定种Neoechinorhynchus sp.和异肉吸虫未定种Allocreadium sp.。感染率从高到低依次为新棘吻虫未定种、聂氏似短节绦虫、异肉吸虫未定种、对盲囊线虫和束首线虫未定种。平均丰度从高到低依次为聂氏似短节绦虫、新棘吻虫未定种、束首线虫未定种、异肉吸虫未定种和对盲囊线虫。群落的Marga...     

Phylogenetic analysis of European species of Proteocephalus (Cestoda: Proteocephalidea): compatibility of molecular and morphological data, and parasite-host coevolution.

The phylogeny of European species of the tapeworm genus Proteocephalus was studied, based on partial 18S rDNA and morphological data. The group was found to be monophyletic. The analysis showed a low informative value of available morphological characters in comparison with molecular data. The morphological matrix resulted in a poorly resolved tree which is, however, compatible with the topology (Proteocephalus osculatus (Proteocephalus torulosus (Proteocephalus macrocephalus, Proteocephalus filicollis) (Proteocephalus tetrastomus, Proteocephalus percae, Proteocephalus longicollis))) based on the 18S rDNA data. A comparison performed by the program TreeMap showed a lack of significant congruency between parasite and host phylogenies. Therefore, the distribution of species in their hosts appears to be independent of the phylogeny and it is likely to be a result of host-switching, rather than co-speciation events.     

Isolation and characterization of microsatellite DNA loci in sea bass,Lates calcarifer Bloch

Polymerase chain reaction (PCR)‐based isolation of microsatellite arrays (PIMA) technique was used to isolate seven polymorphic microsatellite loci in sea bass, Lates calcarifer Bloch. A total of 62 samples of wild and cultivated sea bass collected from a few populations within Peninsular Malaysia were used in the study. For seven polymorphic loci, the number of alleles ranged from four to nine and locus heterozygosities ranged from 0.710 to 1.000. The loci will be useful for studying population structure, genetic variability of wild and hatchery stocks of L. calcarifer and broodstock management purposes.     

西藏黑斑原鮡消化道寄生蠕虫的群落结构和感染情况

为了解西藏特有鱼类黑斑原鮡(Glyptosternum maculatum)消化道寄生蠕虫的群落结构和感染情况, 于2019年5—8月对383尾黑斑原鮡进行了调查。在黑斑原鮡消化道中共发现7种寄生蠕虫, 分别为深槽绦虫未定种(Bothriocephalus sp.)、原头绦虫未定种(Proteocephalus sp.)、异肉吸虫未定种(Allocreadium sp.)、新棘吻虫未定种(Neoechinorhynchus sp.)、裸鲤棘头虫(Echinorhynchus gymnocyprii)、Contracaecum eudyptulae和杆咽线虫未定种(Rhabdochona sp.), 并对各个物种的形态特征进行了描述。将黑斑原鮡按整个群体、不同性别和不同全长群体进行划分, 分别对其消化道寄生蠕虫的群落多样性和优势虫种进行分析, 并对各寄生蠕虫物种的感染情况进行统计。结果表明: 在黑斑原鮡群体中, 消化道寄生蠕虫群落的Shannon-Wiener指数为1.53, Berger-Parker指数为0.37, 优势物种为C. eudyptulae, 其感染数量、感染率、感染强度和平均丰度均为最高; 在黑斑原鮡不同性别群体中, Shannon-Wiener指数为0.26—1.57, Berger-Parker指数为0.34—0.93, 优势物种为C. eudyptulae, 雄性群体中新棘吻虫未定种也为优势虫种, 两者的感染率和平均丰度均较高; 在黑斑原鮡不同全长群体中, Shannon-Wiener指数为0.22—1.59, Berger-Parker指数为0.34—0.94, 优势物种为C. eudyptulae或新棘吻虫未定种, 感染率和平均丰度基本以二者为最高。研究进一步明确了西藏鱼类寄生虫的种类组成和寄生特点, 为研究体内寄生蠕虫的环境适应性及与宿主的协同进化提供基础资料。     

Parasitic helminths infection in Coho salmón, Oncorhynchus kisutch, during their return to Simpson river, Chile]

Between may and july 1994, 17 adult returning salmons, Oncorhynchus kisutch, were collected in the River Simpson, Chile. All fishes showed infection by plerocercoids of Diphyllobothrium sp. in different locations: stomach, spleen, liver, mesenteries and gonads. Infection with larval cestodes of an unidentified species of Phillobothriidae was determined in the intestine of seven (41.2%) salmons and its prevalences of infection showed significant differences between female and male salmons. The 94.4% of total plerocercoids of Diphyllobothrium were isolated from the stomach wall. Prevalence and mean intensity of infection by Diphyllobothrium sp. did not show significant differences between fishes of different sex.     

Mineral composition in fillets of sea bass (Dicentrarchus labrax) and sea bream (Sparus aurata): a comparison of cultured and wild fish

The objective of this study was to determine some of the trace mineral elements in four commercial feeds commonly available in Turkey for marine culture and in fillets of cultured and wild sea bass (Dicentrarchus labrax) and sea bream (Sparus aurata). The feeds and cultured fish were from four different fish farms operating in the same region but with four slightly different feeds. Concentrations of Iron (Fe), Zinc (Zn), Manganese (Mn), Copper (Cu), Lead (Pb), Cobalt (Co), Nickel (Ni), Chromium (Cr), and Cadmium (Cd) were analyzed in the feeds and fillets of cultured as well as wild fish. Significant differences in the mineral concentrations existed within feed groups, cultured fish groups as well as between cultured and wild fish. Fe, Zn, and Mn in the feeds, Fe, Co, and Zn in sea bass and Fe, Zn and Co in sea bream were predominant among the nine analyzed minerals. Fe, Zn, Mn, Cr, and Ni contents in the fillets of wild sea bass were significantly, (P < 0.05) lower than those of the cultured sea bass groups. Co, Cr, Pb, and Ni in the fillets of wild sea bream were also significantly (P < 0.05) lower than those of cultured sea bream groups. These differences in trace elements in the cultured and wild fish were probably related to differences in their dietary mineral concentrations.     

Immune and histopathologic responses of DNA-vaccinated hybrid striped bass Morone saxatilis x M. chrysops after acute Mycobacterium marinum infection

The post-challenge immune and histopathologic responses of hybrid striped bass vaccinated with a DNA vaccine encoding the Mycobacterium marinum Ag85A gene and subsequently challenged with M. marinum were investigated. Juvenile hybrid striped bass Morone saxatilis x M. chrysops were injected intramuscularly with 25 or 50 microg DNA plasmid and developed significant specific protective responses to live bacterial challenge 120 d post-vaccination. Both vaccine groups demonstrated increased survival, reduced splenic bacterial counts, and reduced granuloma formation compared to the control groups 14 d after challenge with approximately 8 x 10(5) cfu M. marinum g(-1) fish body wt. The vaccine groups also developed more rapidly and significantly increased antibody and lymphoproliferative responses post-challenge compared to control groups, and these post-challenge immune responses appear to be vital against M. marinum infection in vaccinated hybrid striped bass. No significant differences in immune responses were recognized between the 25 and 50 microg vaccination groups, and these groups eventually experienced mortalities, splenic bacterial counts, and granuloma formation 28 d post-challenge comparable to those of the control groups at 14 d post-challenge. Therefore, vaccination of hybrid striped bass with a DNA vaccine encoding the M. marinum Ag85A gene provided significant but limited duration of protection against an acute high-dose M. marinum challenge.     

Experimental trophic ecology of juvenile largemouth bass,Micropterus salmoides,and blue tilapia,Oreochromis aureus

Synopsis The potential for feeding competition between largemouth bass, Micropterus salmoides, and blue tilapia, Oreochromis areus, in Lake Fairfield, Texas was evaluated experimentally. Largemouth bass and blue tilapia were grown in cages alone and in combination with each other. The fish were allowed to feed on the natural food within the lake. Largemouth bass grown in combination with blue tilapia were significantly shorter and weighed less than largemouth bass grown alone. Blue tilapia grown in combination with largemouth bass were statistically significantly longer and heavier than blue tilapia grown alone. Largemouth bass grown alone had diets (volume and number of food items) significantly different than the largemouth bass grown with the blue tilapia. Largemouth bass fed primarily on chironomid larvae and pupae, and odonates, whereas blue tilapia consumed vegetable matter, detritus, and chironomid larvae. Length and weight differences between large-mouth bass grown alone and in combination with blue tilapia, in conjunction with the largemouth bass diet shift, support the theory that these two species compete for food resources.     

Description of two new gill myxozoans from smallmouth (Micropterus dolomieu) and largemouth (Micropterus salmoides) bass

Two previously undescribed species of myxozoan parasites were observed in the gills of bass inhabiting the Potomac and James River basins. They are described using morphological characteristics and small-subunit (SSU) rDNA gene sequences. Both were taxonomically identified as new species of Myxobolus; Myxobolus branchiarum n. sp. was found exclusively in smallmouth bass, and Myxobolus micropterii n. sp. was found in largemouth and smallmouth bass. Small, spherical, white plasmodia of M. branchiarum from smallmouth bass were observed grossly in the gills; these plasmodia had an average length of 320.3 μm and width of 246.1 μm. The development of the plasmodia is intralamellar in the secondary lamellae of the gills. Mature spores were pyriform in shape with a length of 12.8 ± 1.4 (8.1-15.1) μm and width of 6.9 ± 1.1 (4.0-9.0) μm. Analysis of SSU rDNA identified M. branchiarum in a sister-group to 3 species of Henneguya , although morphologically caudal appendages were absent. Myxobolus micropterii observed in the gills of largemouth and smallmouth bass had larger, ovoid, cream-colored plasmodia with an average length of 568.1 μm and width of 148.1 μm. The cysts developed at the distal end of the gill filament within the primary lamellae. The mature spores were ovoid in shape with a length of 10.8 ± 0.7 (9.2-12.2) μm and width of 10.6 ± 0.6 (9.0-11.8) μm. SSU rDNA analysis placed M. micropterii in a sister group with Henneguya lobosa and Myxobolus oliveirai . The highest prevalence of M. branchiarum was observed in the gills of bass collected from the Cowpasture River (50.9%). Prevalence was 44.6% in bass from the Potomac River and only 4.3% in bass collected from the Shenandoah River. A seasonal study of M. branchiarum , which included both infected and uninfected smallmouth bass, determined that a significantly higher intensity was observed in the spring than in the summer (P < 0.001) or fall (P = 0.004). In an analysis excluding uninfected bass, a higher intensity was observed in the spring than in the summer (P = 0.001) or fall (P = 0.008). Prevalence and seasonal differences were not determined for M. micropterii .     

Synonymy of shape Proteocephalus pollanicola Gresson, 1952 (Cestoda: Proteocephalidae), a parasite of pollan,shape Coregonus autumnalis pollan,with shape P. exiguus La Rue, 1911

The systematic status of the tapeworm Proteocephalus pollanicola Gresson, 1952, a parasite of pollan Coregonus autumnalis pollan Thompson, was evaluated on the basis of freshly collected material from the type-locality (Lough Neagh, Northern Ireland). Comparison of morphological, biometrical and DNA data (RAPD method) from P. pollanicola and from P. exiguus La Rue, 1911, a very common parasite of coregonid fish, did not find any substantial differences between them to confirm the validity of P. pollanicola. Accordingly, P. pollanicola is considered to be a synonym of P. exiguus, a widely distributed parasite in the Holarctic.     

Chemical structures and immunolocalization of glycosphingolipids isolated from Diphyllobothrium hottai adult worms and plerocercoids.

Glycosphingolipids (GSLs) were purified from adults and plerocercoids of the tapeworm Diphyllobothrium hottai, and their chemical structures were determined. Total lipid fractions prepared from chloroform/methanol extracts of whole tissues were fractionated successively on ion-exchange chromatography, silicic acid column chromatography, and preparative TLC. The purified GSLs were characterized by methylation analysis, TLC-immunostaining, liquid secondary ion MS, MALDI-TOF MS, and 1H-NMR. Ten GSLs were isolated from adult worms and four from plerocercoids, comprising mono-, di-, tri-, tetra-, and pentasaccharides. The GSL Gal beta 1-4(Fuc alpha 1-3)Glc beta 1-3Gal beta 1-Cer was found in adult worms but not in plerocercoids, whereas Ga lbeta 1-4 (Fuc alpha 1-3)Glc beta 1-3(Gal beta 1-6)Gal beta 1-Cer was found in both adult worms and plerocercoids. We previously found a similar series of GSLs in plerocercoids of the cestode Spirometra erinaceieuropaei, and termed them 'spirometosides'[Kawakami, Y. et al. (1996) Eur J. Biochem. 239, 905-911]. The core structure of spirometosides, Gal beta 1-4Glc beta 1-3 Gal beta 1-Cer, may have taxonomic significance, being characteristic of pseudophyllidean tapeworms. In the present study, GSL compositions were significantly different between adults and plerocercoids, and growth-dependent changes in composition were documented. We found a novel dihexosylceramide, Glc beta 1-3Gal beta 1-Cer, which is a possible precursor for spirometosides. Immunohistochemical examination showed that spirometoside GSLs are highly enriched in the inner surface of bothria, the major point of contact between the adult worm and the host's intestine. Our findings indicate that spirometosides are involved in host-parasite interaction.     

Ontogeny of B and T cells in sea bass (Dicentrarchus labrax, L.)

Monoclonal antibodies specific to sea bass Ig heavy (WDI 1) and light (WDI 3) chains and T cells (DLT15) were used in an ontogenetic study of sea bass by flow cytometry and immunocytochemistry. The influence of weight and age, as well as season, on B cell development was studied in the fastest and slowest growing offspring from the same spawn (5-305 days post hatch: dph). Additionally, B and T cell development was followed in samples of different offspring (5-137 dph). The results suggest that DLT15 recognises very early (pre-?) T cells as well as mature T cells and that these very early T cells might have their origin in a different compartment and subsequently mature in the thymus. They also appeared much earlier in ontogeny (between 5-12 dph onwards) than pre-B cells having cytoplasmic Ig (from 52 dph onwards). With the monoclonal antibodies used, adult levels of T and B cells were both reached between 137-145 dph, suggesting that sea bass is immunologically mature from at least that age onwards. As in other teleosts, the thymus appears to be the primary organ for T lymphocytes and head kidney the primary organ for B lymphocytes. For sea bass, age seems to be more important in determining B cell maturation than body weight.     

Interactions between bluefish and striped bass: Behavior of bluefish under size- and number-impaired conditions and overlap in resource use

A decline in bluefish (Pomatomus saltatrix L.) recreational landings during the 1990s and the early 2000s led to multiple theories on the ultimate cause. One theory was that a large portion of the bluefish population moved offshore and was unavailable to nearshore recreational fishers; one reason given for the movement offshore was increased competition with striped bass (Morone saxatilis W.). We conducted laboratory experiments (feeding and non-feeding) to examine behavioral interactions between adult bluefish and sub-adult striped bass in a large (121,000 L) research aquarium. Additionally, we examined diet and habitat overlap of bluefish and striped bass from the fall and spring bottom trawl surveys conducted by the National Marine Fisheries Service. Observations of feeding trials for the following treatments were made: non-impaired (i.e., same number and size of bluefish and striped bass), size-impaired (i.e., large striped bass/small bluefish), number-impaired (i.e.,10 striped bass/3bluefish), and single-species controls. Within a species, there was no difference in a variety of behavioral measures (e.g., attack rate, capture success, ingestion rate, and activity) between mixed- and control treatments under non-impaired or size-impaired conditions. However, behavior of number-impaired bluefish differed from control and size-impaired fish suggesting that striped bass may have a negative influence on bluefish foraging when bluefish are “out-numbered”. Feeding had a strong effect on swimming speeds for both species. Diet and habitat overlap between bluefish and striped bass in continental shelf waters was low. Overall, foraging behavior in mixed-species treatments and field observations suggest no competitive interactions between adult bluefish and sub-adult striped bass.     

Parasites as indicator of fish behaviour

In the present study two species of gobies, Pomatoschistus microps and P. minutus from southwest Wales were studied and appearance of some unusual parasite of gobies, were used as an indicator for fish behaviour. The occurrence of pleurocercoids of Ligula intestinalis in the body cavity of these fish and Proteocephalus sp., excysted metacercariae and adult of Timoniella spp., excysted metacercariae of Bucephalus baeri , the excysted metacercariae of Podocotyle atomon and progenetic adult of Bucephaloides gracilescens in their gut indicate host anadromous, cannibalistic and scavenging behaviour.     

Development of a bacterial challenge test for gnotobiotic sea bass (Dicentrarchus labrax) larvae

The use of probiotic microorganisms in aquaculture is gaining a lot of interest. Gnotobiotic model systems are required in order to fully understand the effects and modes-of-action of these microorganisms, as the native microbial communities present in non-sterile animals can lead to false conclusions. In this study, a gnotobiotic sea bass larvae ( Dicentrarchus labrax ) test system was developed. In order to obtain bacteria-free animals, the eggs were disinfected with glutaraldehyde and subsequently incubated in a solution of rifampicin and ampicillin. Axenity was confirmed using culture-dependent and -independent techniques. The gnotobiotic larvae were fed axenic Artemia sp. from 7 days after hatching onwards. In the challenge test, one of the three opportunistic pathogens, Aeromonas hydrophila , Listonella anguillarum serovar O1 and O2a, was added to the model system via the water and encapsulated in Artemia sp. Only serovar O2a led to increased mortality in the sea bass larvae. The presented gnotobiotic model can be used for research on, among others, reciprocal metabolic effects between microorganisms and the host (e.g. as measured by gene expression), immunostimulants, pharmacological research and the histological development of the gastrointestinal tract and growth of larvae.