Larval gryporhynchid tapeworms (Cestoda: Cyclophyllidea) of British freshwater fish, with a description of the pathology caused by Paradilepis scolecina

Larvae of the cyclophyllidean tapeworms Paradilepis scolecina (Rudolphi, 1819), Neogryporhynchus cheilancristrotus (Wedl, 1855) and Valipora campylancristrota (Wedl, 1855), are described from British freshwater fish. The morphometrics of the rostellar hooks, infection characteristics and host ranges of these parasites from fisheries in England and Wales are presented. Difficulties in the detection, handling and identification of these tapeworms are highlighted, and may in part explain the paucity of records from Britain. Tissue digestion was shown to be a useful technique for the examination of these parasites, providing clear and consistent preparations of the rostellar hooks for measurement. The pathological changes caused by P. scolecina to the liver of wild tench, Tinca tinca, are detailed for the first time. Tapeworms located in the hepatic parenchyma and pancreatic tissues caused little pathological damage and invoked only mild inflammatory responses. The small size of these tapeworms and their encapsulation within host tissues appear to limit the severity of pathology, compared with parasites that insert their rostellum during attachment

Lipid and fatty acid composition of parasitic caligid copepods belonging to the genus Lepeophtheirus

Sea lice are copepod ectoparasites that constitute a major barrier to the sustainability and economic viability of marine finfish aquaculture operations worldwide. In particular, the salmon louse, Lepeophtheirus salmonis, poses a considerable problem for salmoniculture in the northern hemisphere. The free-swimming nauplii and infective copepodids of L. salmonis are lecithotrophic, subsisting principally on maternally-derived lipid reserves. However, the lipids and fatty acids of sea lice have been sparsely studied and therefore the present project aimed to investigate the lipid and fatty acid composition of sea lice of the genus Lepeophtheirus obtained from a variety of fish hosts. Total lipid was extracted from eggs and adult female Lepeophtheirus salmonis obtained from both wild and farmed Atlantic salmon (Salmo salar L.) sampled at two time points, in the mid 1990’s and in 2009. In addition, L. salmonis from wild sea trout (Salmo trutta L.) and L. hippoglossi from wild Atlantic halibut (Hippoglossus hippoglossus L.) were sampled and analyzed. The lipids of both females and egg strings of Lepeophtheirus were characterized by triacylglycerol (TAG) as the major neutral (storage) lipid with phosphatidylcholine and phosphatidylethanolamine as the major polar (membrane) lipids. The major fatty acids were 22:6n-3 (DHA), 18:1n-9 and 16:0, with lesser amounts of 20:5n-3, 22:5n-3 and 18:0. L. salmonis sourced from farmed salmon were characterized by higher levels of 18:2n-6 and 18:3n-3 than lice from wild salmon. Egg strings had higher levels of TAG and lower DHA compared to females, whereas L. hippoglossi had lower levels of TAG and higher DHA than L. salmonis. The results demonstrate that the fatty acid compositions of lice obtained from wild and farmed salmon differ and that changes to the lipid and fatty acid composition of feeds for farmed salmon influence the louse compositions

Sharing and community curation of mass spectrometry data with Global Natural Products Social Molecular Networking

The potential of the diverse chemistries present in natural products (NP) for biotechnology and medicine remains untapped because NP databases are not searchable with raw data and the NP community has no way to share data other than in published papers. Although mass spectrometry techniques are well-suited to high-throughput characterization of natural products, there is a pressing need for an infrastructure to enable sharing and curation of data. We present Global Natural Products Social molecular networking (GNPS, http://gnps.ucsd.edu), an open-access knowledge base for community wide organization and sharing of raw, processed or identified tandem mass (MS/MS) spectrometry data. In GNPS crowdsourced curation of freely available community-wide reference MS libraries will underpin improved annotations. Data-driven social-networking should facilitate identification of spectra and foster collaborations. We also introduce the concept of ‘living data’ through continuous reanalysis of deposited data

The use of statistical classifiers for the discrimination of the species of the genus Gyrodactylus (Monogenea) parasitising salmonids

This study applies flexible statistical methods to morphometric measurements obtained via light and scanning electron microscopy (SEM) to discriminate closely related species of Gyrodactylus parasitic on salmonids. For the first analysis, morphometric measurements taken from the opisthaptoral hooks and bars of 5 species of gyrodactylid were derived from images obtained by SEM and used to assess the prediction performance of 4 statistical methods (nearest neighbours; feed-forward neural network; projection pursuit regression and linear discriminant analysis). The performance of 2 methods, nearest neighbours and a feed-forward neural network provided perfect discrimination of G. salaris from 4 other species of Gyrodactylus when using measurements taken from only a single structure, the marginal hook. Data derived from images using light microscopy taken from the full complement of opisthaptoral hooks and bars were also tested and nearest neighbours and linear discriminant analysis gave perfect discrimination of G. salaris from G. derjavini Mikailov, 1975 and G. truttae Gläser, 1974. The nearest neighbours method had the least misclassifications and was therefore assessed further for the analysis of individual hooks. Five morphometric parameters from the marginal hook subset (total length, shaft length, sickle length, sickle proximal width and sickle distal width) gave near perfect discrimination of G. salaris. For perfect discrimination therefore, larger numbers of parameters are required at the light level than at the SEM level

The description of Gyrodactylus corleonis sp.n. and G. neretum sp.n. (Platyhelminthes: Monogenea) with comments on other gyrodactylids parasitising pipefish (Pisces: Syngnathidae).

The current work describes two new species of Gyrodactylus von Nordmann, 1832 collected from pipefish Syngnathus scovelli (Evermann et Kendall) and Syngnathus typhle L. during two separate gyrodactylosis episodes on fish held in a public aquarium located in northern Italy. The gyrodactylids collected from the skin, fins and gills of pipefish were subjected to a morphological analysis of the attachment hooks and the morphometric data were compared to the four species of Gyrodactylus previously described from syngnathid hosts, namely G. eyipayipi Vaughan, Christison, Hansen et Shinn, 2010, G. pisculentus Williams, Kritsky, Dunnigan, Lash et Klein, 2008, G. shorti Holliman, 1963 and G. syngnathi Appleby, 1996. Principal components analysis (PCA) of the morphological data indicated six clusters; two discrete groups among the specimens taken from the pipefish held in the Italian aquarium and four further groups representing G. eyipayipi, G. pisculentus, G. shorti and G. syngnathi. Molecular sequences of the ribosomal internal transcribed spacers (ITS1 and ITS2) and the 5.8S gene for the new species considered here were then compared with those available for other species in GenBank. The comparison did not reveal any identical match, supporting the morphological analysis that Gyrodactylus corleonis sp. n. from S. typhle and Gyrodactylus neretum sp. n. from S. scovelli represent distinct species. Both G. corleonis and G. neretum possess robust hamuli, marginal hook blades that curve smoothly from their sickle base to a point beyond the toe and, ventral bars with a broad median portion and a reduced membrane. Gyrodactylus corleonis, however, can be distinguished on the basis of its heart-shaped ventral bar; G. neretum has a 1:2 hamulus point:shaft ratio and a rectangular-shaped ventral bar. A redescription of the haptoral hard parts of the four species previously recorded on pipefish is also presented

Interaction and effects of graded levels of dietary phytic acid on the moulting performance, whole body mineral composition and availability on the freshwater prawn Macrobrachium rosenbergii

The presence of anti-nutritional factors such as phytic acid (PA) in a number of potentially useful plant ingredients has been a major impediment to their use as replacements for fishmeal in aquafeeds. This study builds on an earlier studying investigating the growth performance and nutrient utilisation in the juvenile Malaysian giant river prawn, Macrobrachium rosenbergii exploring the effects and interactions of dietary PA with minerals on growth (somatic tissue). Additionally, the study set out to determine the changes in whole-body mineral composition and also on muscle tissues and the carapace, when different levels of PA were included within the diet. The hypothesis under test was that PA, as a mineral-binding agent by chelating di- and trivalent cations inhibits mineral availability. To explore this, effects of graded levels of PA (i.e. 0.26–control, 6.48, 11.28, 16.53, 21.45 and 26.16 g PA kg−1) on the moult frequency and mineral availability in juvenile M. rosenbergii (mean initial carapace length of 6.22 ± 0.52 mm; mean initial weight of 0.20 ± 0.01 g; n = 20 per replicate) fed over a period of 140 days were determined. The levels of PA assessed in this feed trial had no major detrimental effects on moult frequency. Negative effects (p < 0.05) of high PA levels (i.e. 21.45–26.16 g PA kg−1), however, were found on the whole-body phosphorus concentration. An increasing trend, although not significantly so, was recorded for the calcium content in the whole-body and carapace with increasing PA inclusion. Significant changes (p < 0.05) were observed in the levels of zinc, copper, potassium and sodium in the carapace, particularly in the prawns fed the diet containing 11.28 g PA kg−1, which suggests that the specific minerals were either selectively utilised or retained in the carapace. These changes may have a serious impairment hence caution should be exercised to ensure that the anti-nutritive effects of PA are minimised

Interaction and effects of graded levels of dietary phytic acid on the moulting performance, whole body mineral composition and availability on the freshwater prawn Macrobrachium rosenbergii

The presence of anti-nutritional factors such as phytic acid (PA) in a number of potentially useful plant ingredients has been a major impediment to their use as replacements for fishmeal in aquafeeds. This study builds on an earlier studying investigating the growth performance and nutrient utilisation in the juvenile Malaysian giant river prawn, Macrobrachium rosenbergii exploring the effects and interactions of dietary PA with minerals on growth (somatic tissue). Additionally, the study set out to determine the changes in whole-body mineral composition and also on muscle tissues and the carapace, when different levels of PA were included within the diet. The hypothesis under test was that PA, as a mineral-binding agent by chelating di- and trivalent cations inhibits mineral availability. To explore this, effects of graded levels of PA (i.e. 0.26–control, 6.48, 11.28, 16.53, 21.45 and 26.16 g PA kg−1) on the moult frequency and mineral availability in juvenile M. rosenbergii (mean initial carapace length of 6.22 ± 0.52 mm; mean initial weight of 0.20 ± 0.01 g; n = 20 per replicate) fed over a period of 140 days were determined. The levels of PA assessed in this feed trial had no major detrimental effects on moult frequency. Negative effects (p < 0.05) of high PA levels (i.e. 21.45–26.16 g PA kg−1), however, were found on the whole-body phosphorus concentration. An increasing trend, although not significantly so, was recorded for the calcium content in the whole-body and carapace with increasing PA inclusion. Significant changes (p < 0.05) were observed in the levels of zinc, copper, potassium and sodium in the carapace, particularly in the prawns fed the diet containing 11.28 g PA kg−1, which suggests that the specific minerals were either selectively utilised or retained in the carapace. These changes may have a serious impairment hence caution should be exercised to ensure that the anti-nutritive effects of PA are minimised.This project was supported by the Ministry of Higher Education Malaysia and University Malaysia Terengganu (UMT) as part of a PhD programme of study.Peer reviewe