Use of beneficial microorganisms in live food to control the appearance of diseases during the cultivation of aquatic animals

La cría de larvas de peces y crustáceos es una etapa crucial de la acuicultura, durante la cual se deben implementar cultivos de presas vivas como rotíferos, braquiópodos, anélidos y copépodos que servirán de alimento a las larvas. Estos cultivos auxiliares son potencialmente un vector para el ingreso de patógenos que pueden ocasionar grandes mortalidades. Por esta razón es cada vez más frecuente el uso de antibióticos, con el fin de prevenir o tratar enfermedades en cultivos acuáticos. Sin embargo, el uso indiscriminado de los mismos ha facilitado la aparición de cepas de bacterias multiresistentes, con graves consecuencias ambientales y para la salud animal y humana. Múltiples alternativas biotecnológicas, preventivas y curativas, tales como el uso de probióticos, bacteriófagos e inmunoestimulantes se han desarrollado como estrategias para reducir el uso de antibióticos en los cultivos, ya sea para eliminar patógenos o para fortalecer el sistema inmune de los organismos cultivados.Larval rearing of fish and crustaceans is a crucial stage in aquaculture in which live pray culture, such as rotifers, brachiopods, annelids and copepods, must be implemented as food source for larvae. These auxiliary cultures can be a potential vector for pathogens entry that can cause high mortality. This is one reason for antibiotic use in aquaculture leading to the growth of multiresistant bacterial strains. However, the wrong use of this tools it's also a great concern worldwide regarding environmental, animal and human health issues. Multiple biotechnological preventive and therapeutic strategies, such as the use of probiotics, bacteriophages and immune stimulants, have been developed to reduce the use of antibiotics in aquaculture in order to eliminate pathogens as well as to strengthen the immune system of the cultured organisms

Exploring the long-term colonisation and persistence of probiotic-prophylaxis species on the gut microbiome of preterm infants: a pilot study

Preterm infants suffer from a higher incidence of acute diseases such as necrotising enterocolitis and sepsis. This risk can be mitigated through probiotic prophylaxis during admission. This reduction in risk is likely the result of acute modulation of the gut microbiome induced by probiotic species, which has been observed to occur up until discharge. We aimed to determine if this modulation, and the associated probiotic species, persisted beyond discharge. We conducted both a cross-sectional analysis (n= 18), at similar to 18 months of age, and a longitudinal analysis (n= 6), from admission to 18 months of the gut microbiome of preterm infants using both shotgun metagenomics and 16S rRNA profiling respectively. The 16S amplicon sequencing revealed that the microbial composition of the probiotic-supplemented infants changed dramatically over time, stabilising at discharge. However, species from the probiotic Infloran (R), as well as positive modulatory effects previously associated with supplementation, do not appear to persist beyond discharge and once prophylaxis has stopped. Conclusions: Although differences exist between supplemented and non-supplemented groups, the implications of these differences remain unclear. Additionally, despite a lack of long-term colonisation, the presence of probiotics during early neonatal life may still have modulatory effects on the microbiome assembly and immune system training

Microbiome diversity and dysbiosis in aquaculture

With the continuous growth of the human population and associated need for high‐quality protein, the aquaculture sector will be required to increase significantly in productivity. This growth in productivity will be achieved through more efficient use of resources like feeds, genetic improvement and limiting the impacts of disease. One of the key links between animal productivity and disease is that of microbial diversity, with high‐throughput sequencing technologies increasing our understanding of the role microorganisms play in health, development and physiology of vertebrate and invertebrate hosts alike. Increasing our understanding of microbial–host interactions will help avoid or manage dysbiosis in aquaculture systems with the final aim of improving productivity. We review the current literature, which indicates that there is an association between productivity and microbial diversity in aquaculture systems, as changes in bacterial microbiomes are implicated in animal performance, in disease development associated with both bacterial and viral origin, and in dysbiosis triggered by environmental stressors or diet choice. Dysbiosis, whether in the form of the loss of beneficial bacteria, or the expansion of pathogens or potentially harmful microorganisms, can be used as an indicator tool for productivity monitoring purposes. Development of management strategies towards preserving the microbial balance, including maintaining or increasing diversity in the host, is critical for the health of cultured aquatic animals and will likely be critical for the expansion of aquaculture

Adverse effect of early-life high-fat/high-carbohydrate ("Western") diet on bacterial community in the distal bowel of mice

Obesity and other lifestyle diseases in modern society can be related to historical dietary changes from diets balanced in omega-6 and omega-3 to the unbalanced "Western-type" diet. It is recognized that diet influences the murine and human gut microbiome, and most research indicates that microbial diversity and composition are altered by high-fat diets (HFDs). However, good knowledge about the effects of early exposure to HFD on the maturation and structure of the bacterial community is limited. Using mice as model, we hypothesized that an HFD alters the early dynamic of the gut bacterial community toward an unstable/unhealthy state. By sequencing the V3 and V4 regions of the 16S ribosomal ribonucleic acid gene, we investigated the bacterial community in fecal samples of mice fed a control diet and an HFD at weaning (sampling time 1) and after 8 weeks of dietary intervention (11weeks of age; sampling time 2). Natural temporal microbiome maturation was evidenced by a general increase in microbial diversity and shifts in microbial community between sampling times 1 and 2 toward a mature community. However, the HFD led to significant structural segregation of the microbiome compared with controls; the HFD diet repressed health-enhancing bacteria (eg, Bifidobacterium and Akkermansia) and promoted health-detracting bacteria (ie, those associated with gut disorders, eg, Dorea). We suggest that early-life consumption of HFD negatively impacts the natural gut bacterial community maturation leading toward a potentially persistent unhealthy stage.status: publishe

Bacterial signatures of productivity decay in Penaeus monodon ponds infected with PirA toxin

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Bacterial signatures of productivity decay in Penaeus monodon ponds infected with PirA toxin

The clear relationship between the microbiome and the general well-being of metazoans has motivated the characterization of bacterial communities in cultured species for future microbiome monitoring and modulation to improve productivity. To study the bacterial diversity associated with farmed adult P. monodon at harvest, guts, gastric mills (GM), pond water and sediments were investigated using next-generation sequencing technology in two control ponds (CP1 and CP2) where animals showed a healthy appearance, and two low productive ponds (LP1 and LP2) where animals showed signs of disease. Animals from CP2 were on average at least 4 g heavier than animals from other ponds, and the final yield of both CP was more than double that of LP. LP2 showed the lowest diversity indices, which can potentially be attributed to high abundance of Vibrio spp. and warm water conditions (31.6 +/- 0.3 degrees C on average). The structure of the bacterial community in the gut, GM and water samples was different between CP and LP. Vibrio spp. and anaerobic bacteria (e.g. Fusibacter) were enriched in the gastrointestinal tract of animals from LP (LDA >= 4). While Vibrio can potentially act against the host and other members of the bacterial community, Fusibacter might be an indicator of sulfur compounds accumulation in the animal as the hepatopancreas becomes affected by a PirA toxin. Enrichment of Cyanobacteria in the water (LDA = 4.38) and members of Desulfobacteraceae in sediments of LP (5% on average) could be environmental stress indicators in summer conditions. Characterizing bacterial microbiomes in aquaculture is important to detect indicators of health and productivity that can be used as monitoring tools in the animal s gastrointestinal tract and the environment, ultimately enabling a targeted modulation of the bacterial community for improved production

Parasitic protozoan interactions with bacterial microbiome in a tropical fish farm

The bacterial microbiome is an important component of any aquaculture environment. The interaction between the bacterial microbiome and other microorganisms (e.g. parasites, viruses, or other bacteria) in aquaculture systems can prevent or contribute to disease outbreaks. This study characterised the bacterial composition associated with the abundance of a ciliated protozoan parasite, Chilodonella hexasticha, in gills and freshwater ponds of barramundi, Lates calcarifer, farm in tropical Queensland, Australia, over one year. An environmental DNA (eDNA) approach was used to estimate the abundance of C. hexasticha (copies/μl) in water through SSUrDNA gene qPCR and the relative abundance of bacterial species in water and fish gills through 16S rRNA V3 and V4 metabarcoding. The overall bacterial community diversity, dominated by Actinobacteria (42%), Proteobacteria (28%), Bacteroidetes (10%) and Cyanobacteria (6%), was stable among ponds over the study period (p > .05). Of those that could be identified to species, Flavobacterium columnare, Veillonella dispar and Bdellovibrio bacteriovorus abundance correlated with both high C. hexasticha levels in pond water and high observed fish mortalities (p < .05). Results also revealed significantly higher levels of F. columnare, B. bacteriovorus,Plesiomonas shigelloides, Prostecobactor debontii and Oxalobacter formigenes (p < .05) in gills of fish with high infection levels of C. hexasticha compared to fish with no detected parasite infection. This study demonstrated, for the first time, a link between increased parasitic ciliate abundance, bacterial composition and fish mortalities in a freshwater aquaculture environment and the application of eDNA to investigate pathogen, host and environment interactions