Abstract:The health and environmental risks associated with antibiotic use in aquaculture have promoted bacterial probiotics as an alternative approach to control fish infections in vulnerable larval and juvenile stages. However, evidence-based identification of probiotics is often hindered by the complexity of bacteria-host interactions and host variability in microbiologically uncontrolled conditions. While these difficulties can be partially resolved using gnotobiotic models harboring no or reduced microbiota, most … Show more
“…Such models could confirm the protective effect of essential endogenous bacteria, during Y . ruckeri infection, since our results are mainly predictions and the causal effect can still be difficult to determine (Llewellyn et al, 2014; Pérez‐Pascual et al, 2021).…”
Aims: Given the pivotal role played by the gut microbiota in regulating the host immune system, great interest has arisen in the possibility of controlling fish health by modulating the gut microbiota. Hence, there is a need to better understand of the host-microbiota interactions after disease responses to optimize the use of probiotics to strengthen disease resilience and recovery.
Methods and Results:We tested the effects of a probiotic feed additive in rainbow trout and challenged the fish with the causative agent for enteric red mouth disease, Yersinia ruckeri. We evaluated the survival, host immune gene expression and the gut microbiota composition. Results revealed that provision of probiotics and exposure to Y. ruckeri induced immune gene expression in the host, which were associated with changes in the gut microbiota. Subsequently, infection with Y. ruckeri had very little effect on microbiota composition when probiotics were applied, indicating that probiotics increased stabilisation of the microbiota. Our analysis revealed potential biomarkers for monitoring infection status and fish health. Finally, we used modelling approaches to decipher interactions between gut bacteria and the host immune gene responses, indicating removal of endogenous bacteria elicited by nonspecific immune responses.
Conclusions:We discuss the relevance of these results emphasizing the importance of host-microbiota interactions, including the protective potential of the gut microbiota in disease responses.
“…Such models could confirm the protective effect of essential endogenous bacteria, during Y . ruckeri infection, since our results are mainly predictions and the causal effect can still be difficult to determine (Llewellyn et al, 2014; Pérez‐Pascual et al, 2021).…”
Aims: Given the pivotal role played by the gut microbiota in regulating the host immune system, great interest has arisen in the possibility of controlling fish health by modulating the gut microbiota. Hence, there is a need to better understand of the host-microbiota interactions after disease responses to optimize the use of probiotics to strengthen disease resilience and recovery.
Methods and Results:We tested the effects of a probiotic feed additive in rainbow trout and challenged the fish with the causative agent for enteric red mouth disease, Yersinia ruckeri. We evaluated the survival, host immune gene expression and the gut microbiota composition. Results revealed that provision of probiotics and exposure to Y. ruckeri induced immune gene expression in the host, which were associated with changes in the gut microbiota. Subsequently, infection with Y. ruckeri had very little effect on microbiota composition when probiotics were applied, indicating that probiotics increased stabilisation of the microbiota. Our analysis revealed potential biomarkers for monitoring infection status and fish health. Finally, we used modelling approaches to decipher interactions between gut bacteria and the host immune gene responses, indicating removal of endogenous bacteria elicited by nonspecific immune responses.
Conclusions:We discuss the relevance of these results emphasizing the importance of host-microbiota interactions, including the protective potential of the gut microbiota in disease responses.
“…Group IV was related to Group I with negative-negative correlations; therefore, both were considered as algae-positive groups and contained six RG2 ASVs, namely five Flavobacterium and one Pseudomonas . However, Flavobacterium usually harms fish but not humans [ 34 ], and the increase in Pseudomonas was minimal (0.06 to 0.21%). Fig.…”
Background
Monitoring microbial communities especially focused on pathogens in newly developed wastewater treatment systems is recommended for public health. Thus, we investigated the microbial community shift in a pilot-scale microalgal treatment system for piggery wastewater.
Results
Microalgae showed reasonable removal efficiencies for COD and ammonia, resulting in higher transparency of the final effluent. Metagenome and microbial diversity analyses showed that heterotrophic microalgal cultivation barely changed the bacterial community; however, the mixotrophic microalgal cultivation induced a sudden change. In addition, an evaluation of risk groups (RGs) of bacteria showed that raw piggery wastewater included abundant pathogens, and the microalgal treatment of the raw piggery wastewater decreased the RG2 pathogens by 63%. However, co-cultivation of microalgae and the most dominant RG2 pathogen, Oligella, showed no direct effects between them.
Conclusions
Thus, a microbial interaction network was constructed to elucidate algae-bacteria interrelationships, and the decrease in Oligella was indirectly connected with microalgal growth via Brevundimonas, Sphingopyxis, and Stenotrophomonas. In a validation test, 3 among 4 connecting bacterial strains exhibited inhibition zones against Oligella. Therefore, we showed that microalgal wastewater treatment causes a decrease in RG2 bacteria, which is an indirect impact of microalgae associated with bacteria.
Graphical Abstract
“…Furthermore, the microbial variation was low across all 75 investigated individuals despite being exposed to different conditions for multiple environmental factors, indicating high host selection pressure favouring MSS. Therefore we hypothesise that this Mycoplasma-de ned microbiota is pristine in Atlantic salmon, making our data set a valuable reference for future salmonid microbiota studies, as in aquaculture, where the gut microbiota investigations have been a research eld of increasing interest 18,19,[37][38][39][40][41] .…”
The study of co-evolution between host and microbes has the potential to transform how we understand evolutionary adaptations, yet genuine co-evolutionary relationships are challenging to show. The host's intestinal environment shapes the gut microbiota through the co-existence of bacteria and host. This co-existence influences the fitness of both bacteria and host. How this affects the co-evolution occurring in animals is largely unexplored, mainly due to the complexity of the environment, low host selection, and microbial communities.
We present the first metagenomic derived genome of gut microbiota from wild Atlantic salmon (Salmo salar), a new wild model organism with the microbiota of low complexity and known population structures amenable for investigating co-evolution. Our data reveal a strong host selection of a core gut microbiota dominated by a single Mycoplasma species. Interestingly, we found a concordance between the population structure of the Atlantic salmon host and nucleotide variability of the intestinal Mycoplasma populations conforming to expectations from co-evolution between host and microbe.
Our results show that the stable microbiota of Atlantic salmon has evolved with its salmonid host populations while potentially providing adaptive traits to the salmon host populations, including defence mechanisms and protein synthesis. We highlight Atlantic salmon as a novel model for studying co-evolution between vertebrate hosts and their microbiota.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
