Morpho-physiological digestive features of genetically closely related sympatric lacustrine whitefish forms with different feeding habits.

The effect of different feeding habits on gut morphology and digestive function has been intensively studied during the last decades but sympatric closely related fishes are relatively rare objects of such studies. In the present study, we have identified both morphological and physiological changes in the digestive system of a sympatric pair of whitefish represented by "normal" Coregonus lavaretus pidschian (benthivorous) and "dwarf" C. l.

Comparative study of the gut microbial communities collected by scraping and swabbing in a fish model: a comprehensive guide to promote non-lethal procedures for gut microbial studies.

In the present study, we propose the use of swabs in non-lethal sampling procedures to collect the mucosa-adhered gut microbiota from the posterior intestine of fish, and therefore, we compare the bacterial communities collected by conventional scraping and by swabbing methods. For this purpose, samples of the posterior intestine of rainbow trout () were collected first using the swabbing approach, and after fish euthanasia, by mucosa scraping. Finally, bacterial communities were compared by 16S rRNA gene Illumina sequencing.

Corrigendum: Trophic diversification and parasitic invasion as ecological niche modulators for gut microbiota of whitefish.

[This corrects the article DOI: 10.3389/fmicb.2023.

Metapopulation Structure of Two Species of Pikeworm (, Cestoda) Parasitizing the Postglacial Fish Community in an Oligotrophic Lake.

In the present study, we estimated the levels of infestation of the main fish species that are hosts for two species: and . The prevalence of and infestations in the intestine of their definitive host-pike was similar (71.0% and 77.

Trophic diversification and parasitic invasion as ecological niche modulators for gut microbiota of whitefish.

Introduction: The impact of parasites on gut microbiota of the host is well documented, but the role of the relationship between the parasite and the host in the formation of the microbiota is poorly understood. This study has focused on the influence that trophic behavior and resulting parasitism has on the structure of the microbiome.

Methods: Using 16S amplicon sequencing and newly developed methodological approaches, we characterize the gut microbiota of the sympatric pair of whitefish complex and the associated microbiota of cestodes parasitizing their intestine.

The gut microbiota of parasitizing the swim bladder of the nosed charr morph complex in Lake Kronotskoe (Kamchatka, Russia).

Using the approach of sequencing the V3-V4 region of the 16S rRNA gene, we have analyzed the bacterial diversity associated with the gut and "body" (other parts of nematode after dissection: cuticle, epidermis and longitudinal muscles, etc) of parasitizing the swim bladder of different morphotypes of the nosed charr. Comparisons of the gut microbiota of nematodes with their "body" has revealed that the associated microbiota are closely related to each other. Taxonomic analysis indicated that the relative abundances of the dominant nematode-associated bacteria varied with individual fish.

Localization of the proteinase inhibitor activity in the fish cestode Eubothrium rugosum.

The mechanisms enabling fish tapeworms to avoid proteolytic attacks by digestive enzymes of their fish host have been studied in less detail compared with mammalian cestodes. This study aimed to assess the inhibitory ability towards trypsin and chymotrypsin in Eubothrium rugosum, an intestinal parasite of burbot Lota lota, and establish its localization in the tapeworm. To this end, the worms were treated with Triton X-100 followed by differential centrifugation to isolate the tegumental brush border membrane.

Parasitic copepods Caligus lacustris (Copepoda: Caligidae) on the rainbow trout Oncorhynchus mykiss in cage aquaculture: morphology, population demography, and first insights into phylogenetic relationships.

Herein, data on rainbow trout infections with the copepod Caligus lacustris in cage aquaculture on Lake Ladoga is presented. Caligus lacustris (n = 127 ex.) were collected from a farm in Lake Ladoga housing cage-reared rainbow trout to describe the size-age and sex structure of the copepod population.

Chestnut Shell Tannins: Effects on Intestinal Inflammation and Dysbiosis in Zebrafish.

The aim of the present study was to test the possible ameliorative efficacy of phytochemicals such as tannins on intestinal inflammation and dysbiosis. The effect of a chestnut shell () extract (CSE) rich in polyphenols, mainly represented by tannins, on k-carrageenan-induced intestinal inflammation in adult zebrafish () was tested in a feeding trial. Intestinal inflammation was induced by 0.

Microbial community structure in a host-parasite system: the case of Prussian carp and its parasitic crustaceans.

Aims: The aim of the study was to investigate the skin microbiota of Prussian carp infested by ectoparasites from the genera Argulus and Lernaea.

Methods And Results: Associated microbiota of skin of Prussian carp and ectoparasites were investigated by sequencing of the V3, V4 hypervariable regions of 16S rRNA using Illumina MiSeq sequencing platform.

Conclusions: According to the Spearman rank correlation test, the increasing load of ulcerations of the skin of Prussian carp was weakly negatively correlated with reduction in the abundance of the following taxa: Acrobacter, bacteria C39 (Rhodocyclaceae), Rheinheimera, Comamonadaceae, Helicobacteraceae and Vogesella.

Feeding habits shape infection levels by plerocercoids of the tapeworm in muscle of a sympatric pair of whitefish in an oligotrophic lake.

Lake Teletskoye (West Siberia, Russia) is inhabited by a sympatric pair of whitefish, with each member of the pair being characterized by different feeding habits. Coregonus lavaretus pidschian (Gmelin, 1789) is a large 'benthivorous' form, while C. l.

Seasonal changes in kinetic parameters of trypsin in gastric and agastric fish.

The objective of the present study was to assess if trypsin, a key enzyme involved in protein digestion, presents some kind of functional adaptations to seasonal changes in water temperature in freshwater fish. In order to test this hypothesis, individuals of two fish species Carassius gibelio (agastric) and Perca fluviatilis (gastric) were sampled in the basin of Chany Lake (Siberia, Russia) at two different seasons (spring and summer). Apparent kinetic parameters (K and V) were determined for both species and seasons at the actual pH values in fish guts, and at actual temperatures.

The effect of diet on the structure of gut bacterial community of sympatric pair of whitefishes (): one story more.

In the complex may be found lacustrine sympatric pairs, which serves as an intriguing model for studying different aspects of fish evolutionary biology. One such sympatric whitefish pair inhabits Teletskoye Lake (West Siberia, Russia) and includes a "large" form ( (Gmelin, 1789)) and a "small" form ( (Dulkeit, 1949)). has a narrow trophic specialization and feeds on zooplankton, whereas the diet of is based on benthic prey.

Composition of the microbial communities in the gastrointestinal tract of perch (Perca fluviatilis L. 1758) and cestodes parasitizing the perch digestive tract.

Using the approach of sequencing the V3-V4 region of the 16S rRNA gene, we have analysed the bacterial diversity associated with the distinct compartments of the gastrointestinal tract of perch (Perca fluviatilis) and cestodes (Proteocephalus sp.) parasitizing their digestive tract. The dominant microbiota associated with cestodes (Proteocephalus sp.

Variations of the intestinal gut microbiota of farmed rainbow trout, Oncorhynchus mykiss (Walbaum), depending on the infection status of the fish.

Aims: The aim of the present study was to investigate the composition of the intestinal microbiota during the acute stage of a bacterial infection to understand how dysbiosis of the gut may influence overall taxonomic hierarchy and diversity, and determine if there exists a bacterial taxon(s) that serve as markers for healthy or diseased rainbow trout (Oncorhynchus mykiss).

Methods And Results: From July to September 2015, 29 specimens of 3-year-old (an average weight from 240·9 ± 37·7 to 850·7 ± 70·1 g) rainbow trout O. mykiss were studied.

Diet and other environmental factors shape the bacterial communities of fish gut in an eutrophic lake.

Aims: The aim of this work was to study the gut microbial diversity from eight species of wild fish with different feeding habits, digestive physiology (gastric vs agastric) and provide comparative structural analysis of the microbial communities within their environment (food items, water, sediments and macrophytes).

Methods And Results: The microbiota of fish gut and their prey items were studied using next generation high-throughput sequencing of the 16S ribosomal RNA genes. A scatter plot based on PCoA scores demonstrated the microbiota formed three groups: (i) stomach and intestinal mucosa (IM), (ii) stomach and intestinal content (IC), and (iii) prey and environment.

DNA extraction protocols may influence biodiversity detected in the intestinal microbiome: a case study from wild Prussian carp, Carassius gibelio.

In this investigation, we examined the influence of different DNA extraction protocols on results obtained for intestinal microbiota of Prussian carp. We showed that significant differences were observed in numbers of reads, OTUs, Shannon index and taxonomic composition between two different DNA extraction protocols for intestine of Prussian carp (Carassius gibelio), and differences were also evident between microbial communities in the intestinal mucosa and intestinal content. Statistical analyses of 25 published articles also revealed a significant relationship between methods of DNA extraction and bacterial diversity in fish intestine of freshwater species.

A comparative study on microbiota from the intestine of Prussian carp (Carassius gibelio) and their aquatic environmental compartments, using different molecular methods.

Aims: The aim of this study was to evaluate, via various molecular methods, the possible correlations between microbial community structure of Prussian carp and the environmental compartments of their habitat.

Methods And Results: Microbial communities in the intestine and environmental compartments were studied using PCR-screening, cloning and next-generation high-throughput sequencing of the 16S ribosomal RNA genes. The 16S rDNA metagenomic sequencing showed higher bacterial diversity in comparison with clone libraries, while group-specific PCR showed positive detection of nine bacteria phyla.

Feeding habits and ontogenic changes in digestive enzyme patterns in five freshwater teleosts.

Feeding habits and the activity of digestive enzymes (total alkaline proteases, α-amylase and lipase) from dace Leuciscus leuciscus, roach Rutilus rutilus, Prussian carp Carassius auratus gibelio, perch Perca fluviatilis and pikeperch Sander lucioperca fry were studied in the Malye Chany Lake-Kargat Estuary (western Siberia, Russia). The diet of fry from all studied species was mainly composed of chironomid larvae and zooplanktonic organisms (i.e.