Biomedical subjects

Falk Hildebrand

Publications and source records attributed to Falk Hildebrand.

3 recordsLinked to original sources

PubMed2026

Supplementation with effective microorganisms in earthen ponds affects common carp growth and abundance of specific bacterial families.

BACKGROUND: Effective microorganisms are increasingly explored in aquaculture to improve fish health and growth without leaving harmful residues. However, their efficacy in real-world pond environments remains poorly understood. Here, we conducted a 103-day field experiment to assess the effects of supplementation with two effective commercial microorganism products on the microbial communities and growth performance of common carp (Cyprinus carpio). BACKGROUND: Effective microorganisms were added to the feed and directly to the pond water. Microbial diversity was analysed via 16 S rRNA and whole-genome shotgun sequencing across three environments: water (three time points), sediment (two time points), and fish intestine (one time point) from 25 experimental ponds. Bioinformatics processing was performed using the QIIME2 and MG-TK pipelines with taxonomic classification based on the SILVA database. The results showed that although supplemented bacterial families did not establish significantly in pond environments, fish exposed to specific effective microorganism treatments showed improved growth metrics. CONCLUSIONS: These findings suggest that effective microorganisms can increase carp growth in aquaculture without significantly altering the resident microbial communities, suggesting a promising residue-free alternative to traditional additives in aquaculture.

Animals↗

PubMed2026

Copper is an intestinal habitat filter affecting the gut microbiota interactions with Salmonella Typhimurium.

BACKGROUND: Foodborne pathogens, including Salmonella enterica serovar Typhimurium (S. Typhimurium), pose a significant threat to both human health and livestock productivity. The pandemic S. Typhimurium ST34 clone acquired a genomic island (SGI-4) conferring high copper resistance, an adaptation relevant in the context of the widespread use of copper sulphate at therapeutic levels in pig farming. We investigated how high dietary copper influences the piglet gut microbiota and Salmonella-microbiota interactions that may explain the global spread of S. Typhimurium ST34. RESULTS: An on-farm study combined with faecal shotgun metagenomics revealed that several potential Salmonella competitor species, including Bifidobacterium, Escherichia, and Lactobacillus, were less abundant in piglets on high-copper diets. Anaerobic and aerobic culturing alongside whole genome sequencing of 131 species and copper sulphate susceptibility testing identified copper resistance gene acquisition in selected microbes, particularly within Escherichia. Niche competition assays demonstrated that copper resistance is critical for inter-species competition under high-copper conditions, with Salmonella's Type VI Secretion System providing a distinct advantage over Escherichia in the copper-modified niche. CONCLUSIONS: Our findings suggest that copper supplementation alters the piglet gut environment, impacting competitive dynamics between pathogenic and commensal bacteria, likely to influence the zoonotic transmission of pathogens. Video Abstract.

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PubMed2026

Host immunogenetic variation and gut microbiome functionality in a wild vertebrate population.

BACKGROUND: The gut microbiome (GM) -important for host health and survival- is partially shaped by host immunogenetics. However, to date, no study has investigated the influence of host Major Histocompatibility Complex (MHC) genes on gut microbiome functionality in a wild population. Here we use a natural population of the Seychelles warbler (Acrocephalus sechellensis) to assess the effects of MHC genes on GM taxonomy and functionality using shotgun metagenomics. RESULTS: Our results show that taxonomic GM composition was associated with MHC-II diversity and the presence of one specific MHC-I allele (Ase-ua 7). Specifically, MHC-II diversity was associated with decreased Lactococcus lactis and increased Staphylococcus lloydii abundance, while Ase-ua 7 was linked to reduced Enterococcus casselifavus and Gordonia sp OPL2 but increased Escherichia coli and Vulcaniibacterium thermophilum. These taxonomic changes may reflect differences in MHC-mediated microbial recognition. In contrast, functional GM composition was significantly associated with increasing individual MHC-I diversity but not MHC-II diversity. In particular, increasing MHC-I diversity was associated with an increased prevalence of microbial defence genes but a reduced prevalence of microbial metabolism genes. Analysis also revealed that functional GM networks were more fragmented in high compared to low MHC-I diversity hosts. CONCLUSION: These results suggest that MHC variation (particularly at MHC-I) plays an important role in shaping both the taxonomy and function of the GM in wild vertebrates. In the Seychelles warbler, this results in trade-offs whereby there is an increase in microbial defence and a reduction in GM metabolic potential in individuals with higher MHC-I diversity. Thus, this work sheds light on the possible costs and benefits of maintaining a healthy microbiome, which is essential for understanding how the GM and immune system co-evolve. Video Abstract.

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