RNAseq analysis of whole zebrafish (Danio rerio) larvae revealed the main cellular biological effects of geosmin and microcystin exposure at environmentally relevant concentrations.

Cyanobacterial blooms are common events that releases secondary metabolites into water posing considerable threats to the environment, wildlife, and public health. Some of these metabolites, such as microcystin, have been extensively studied and associated with harmful effects in mammals and aquatic organisms, while the biological effects of others, like geosmin, remain much less investigated. Enhancing our understanding of cyanotoxins effects on organisms is especially relevant facing the complex scenarios projected due to global warming.

Lysin and Lytic Phages Reduce Vibrio Counts in Live Feed and Fish Larvae.

species are naturally found in estuarine and marine ecosystems, but are also recognized as significant human enteropathogens, often linked to seafood-related illnesses. In aquaculture settings, Vibrio poses a substantial risk of infectious diseases, resulting in considerable stock losses and prompting the use of antimicrobials. However, this practice contributes to the proliferation of antimicrobial-resistant (AMR) bacteria and resistance genes.

Sarcopenic metabolomic profile reflected a sarcopenic phenotype associated with amino acid and essential fatty acid changes.

Introduction: Although sarcopenia greatly affects health and quality of life in older people, its pathophysiological causes are not fully elucidated. To face this challenge, omics technologies can be used. The metabolome gives a vision of the interaction between the genome and the environment through metabolic networks, thus contributing in clarifying the pathophysiology of the sarcopenic phenotype.

In-depth analysis of swim bladder-associated microbiota in rainbow trout (Oncorhynchus mykiss).

Our knowledge regarding microbiota associated with the swim bladder of physostomous, fish with the swim bladder connected to the esophagus via the pneumatic duct, remains largely unknown. The goal of this study was to conduct the first in-depth characterization of the swim bladder-associated microbiota using high-throughput sequencing of the V4 region of the 16 S rRNA gene in rainbow trout (Oncorhynchus mykiss). We observed major differences in bacterial communities composition between swim bladder-associated microbiota and distal intestine digesta microbiota in fish.

Effect of Dietary Carbohydrate-to-Protein Ratio on Gut Microbiota in Atlantic Salmon ().

Atlantic salmon () is a carnivorous fish species whose productive performance tends to be suboptimal when fed low-cost carbohydrate rich meals. It is of interest to study the dynamics of gut microbiota communities in salmonids fed high carbohydrate diets since gut microbes are referred to as key players that influence the metabolism and physiology of the host. A study was conducted to determine the effect of feeding a high carbohydrate diet to Atlantic salmon in gut microbiota communities.

Fasting Upregulates , and Without Increasing Ghrelin Levels in Zebrafish () Larvae.

Food intake in fish and mammals is orchestrated by hypothalamic crosstalk between orexigenic (food intake stimulation) and anorexigenic (food intake inhibition) signals. Some of these signals are released by peripheral tissues that are associated with energy homeostasis or nutrient availability. During the fish larva stage, orexigenic stimulation plays a critical role in individual viability.

Performance of Debaryomyces hansenii as a Diet for Rotifers for Feeding Zebrafish Larvae.

The zebrafish larval stage is a critical moment due to high mortality rates associated with inadequate supplies of nutritional requirements. Larval feeding has important challenges associated with such factors as small mouth gape (≈100 μm), the low activity of digestive enzymes, and the intake of live food. A common zebrafish live food at the onset of exogenous feeding is rotifers, mainly Brachionus plicatilis.

Genome Sequence of a Lactococcus lactis Strain Isolated from Salmonid Intestinal Microbiota.

Lactococcus lactis is a common inhabitant of the intestinal microbiota of salmonids, especially those in aquaculture systems. Here, we present a genome sequence of a Lactococcus lactis strain isolated from the intestinal contents of rainbow trout reared in Chile.

Characterization and pathogenicity of Vibrio splendidus strains associated with massive mortalities of commercial hatchery-reared larvae of scallop Argopecten purpuratus (Lamarck, 1819).

Three strains (VPAP16, VPAP18 and VPAP23 strains) were isolated as the most predominant organisms from 3 different episodes of massive mortalities of larval cultures of the Chilean scallop Argopecten purpuratus occurred in different commercial hatcheries located in northern Chile. The main aims of this study were to identify the pathogenic strains and investigate their pathogenic activity. Based on selected phenotypic features and sequence identity of the 16S rRNA gene and the housekeeping gene, RNA polymerase α-chain rpoA, all pathogenic strains were identified as Vibrio splendidus.

Debaryomyces hansenii and Rhodotorula mucilaginosa comprised the yeast core gut microbiota of wild and reared carnivorous salmonids, croaker and yellowtail.

This is the first study using molecular and culture-based methods aimed at investigating the composition of the intestinal yeast microbiota of wild and reared carnivorous salmonids, croaker and yellowtail, to characterize their cores and to evaluate the enzymatic activities of the cultivated yeast. Among 103 samples from salmonids, croaker and yellowtail, yeast were detected in 85.4%, with 43 species identified.

Effect of the dietary inclusion of soybean components on the innate immune system in zebrafish.

Some components of plant-based meals, such as saponins and vegetal proteins, have been proposed as inducers of intestinal inflammation in some fish. However, the molecular and cellular bases for this phenomenon have not been reported. In this work, zebrafish were used as a model to evaluate the effects of individual soybean meal components, such as saponins and soy proteins.

Reduction of soybean meal non-starch polysaccharides and α-galactosides by solid-state fermentation using cellulolytic bacteria obtained from different environments.

Soybean meal (SBM) is an important protein source in animal feed. However, the levels of SBM inclusion are restricted in some animal species by the presence of antinutritional factors (ANFs), including non-starch polysaccharides (NSPs) and α-galactosides (GOSs). The aim of this study was to reduce the soybean meal NSPs and GOSs by solid-state fermentation (SSF) using a combination of cellulolytic bacteria isolated from different environments (termites, earthworms, corn silage and bovine ruminal content).

PCR-TTGE analysis of 16S rRNA from rainbow trout (Oncorhynchus mykiss) gut microbiota reveals host-specific communities of active bacteria.

This study assessed the relative contributions of host genetics and diet in shaping the gut microbiota of rainbow trout. Full sibling fish from four unrelated families, each consisting of individuals derived from the mating of one male and one female belonging to a breeding program, were fed diets containing either vegetable proteins or vegetable oils for two months in comparison to a control diet consisting of only fish protein and fish oil. Two parallel approaches were applied on the same samples: transcriptionally active bacterial populations were examined based on RNA analysis and were compared with bacterial populations obtained from DNA analysis.

Molecular analysis of intestinal microbiota of rainbow trout (Oncorhynchus mykiss).

The aim of this study was to evaluate different molecular tools based on the 16S rRNA gene, internal transcribed spacer, and the rpoB gene to examine the bacterial populations present in juvenile rainbow trout intestines. DNA was extracted from both pooled intestinal samples and bacterial strains. Genes were PCR-amplified and analysed using both temporal temperature gradient gel electrophoresis (TTGE) and restriction fragment length polymorphism methods.

Oxytetracycline treatment reduces bacterial diversity of intestinal microbiota of Atlantic salmon.

The effect of oxytetracycline (OTC) treatment on intestinal bacterial populations in juvenile Atlantic salmon Salmo salar was evaluated. Oxytetracycline was administered by way of medicated feed to fish held in experimental tanks. Restriction fragment length polymorphism and sequencing of 16S rDNA from isolates were used to analyze the intestinal microbiota before, during, and after OTC administration.