Salmonella Phages Affect the Intestinal Barrier in Chicks by Altering the Composition of Early Intestinal Flora: Association With Time of Phage Use

Abstract

Phages show promise in replacing antibiotics to treat or prevent bacterial diseases in the chicken breeding industry. Chicks are easily affected by their environment during early growth. Thus, this study investigated whether oral phages could affect the intestinal barrier function of chicks with a focus on the cecal microbiome. In a two-week trial, forty one-day-old hens were randomly divided into four groups: (1) NC, negative control; (2) Phage 1, 109 PFU phage/day (days 3–5); (3) Phage 2, 109 PFU phage/day (days 8–10); and (4) AMX, 1 mg/mL amoxicillin/day (days 8–10). High-throughput sequencing results of cecal contents showed that oral administration of phages significantly affected microbial community structure and community composition, and increased the relative abundance of Enterococcus. The number of different species in the Phage 1 group was much higher than that in the Phage 2 group, and differences in alpha and beta diversity also indicated that the magnitude of changes in the composition of the cecal microbiota correlated with the time of phage use. Particularly in the first stage of cecal microbiota development, oral administration of bacteriophages targeting Salmonella may cause substantial changes in chicks, as evidenced by the results of the PICRUSt2 software function prediction, reminding us to be cautious about the time of phage use in chicks and to avoid high oral doses of phages during the first stage. Additionally, the Phage 2 samples not only showed a significant increase in the relative abundance of Bifidobacterium and Subdoligranulum, but also improved the intestinal morphology (jejunum) and increased the mRNA expression level of occludin and ZO-1. We concluded that phages do not directly interact with eukaryotic cells. The enhancement of intestinal barrier function by phages in chicks may be related to changes in the intestinal flora induced by phages. This implies that phages may affect intestinal health by regulating the intestinal flora. This study provides new ideas for phage prevention of intestinal bacterial infections and promotes large-scale application of phages in the poultry industry.

Examining the effects of Salmonella phage on the caecal microbiota and metabolome features in Salmonella-free broilers

“…Bacteriophage therapy is a promising approach to controlling zoonotic bacteria, replacing antibiotics to treat or prevent bacterial diseases in poultry production ( Wernicki et al, 2017 ; Żbikowska et al, 2020 ; Clavijo et al, 2022 ; Zhao et al, 2022 ). Specifically, lytic bacteriophages (phages) are ‘natural predators’ that selectively infect and kill their target bacterial host ( Mu et al, 2021 ; Zhao et al, 2022 ).…”

“…Bacteriophage therapy is a promising approach to controlling zoonotic bacteria, replacing antibiotics to treat or prevent bacterial diseases in poultry production ( Wernicki et al, 2017 ; Żbikowska et al, 2020 ; Clavijo et al, 2022 ; Zhao et al, 2022 ). Specifically, lytic bacteriophages (phages) are ‘natural predators’ that selectively infect and kill their target bacterial host ( Mu et al, 2021 ; Zhao et al, 2022 ). Compared to antibiotics, phages have high specificity that usually attacks only their targeted bacterial hosts, indicating minimal disruption to the niche microbiota ( Cieplak et al, 2018 ; Gindin et al, 2019 ).…”

“…Compared to antibiotics, phages have high specificity that usually attacks only their targeted bacterial hosts, indicating minimal disruption to the niche microbiota ( Cieplak et al, 2018 ; Gindin et al, 2019 ). Nevertheless, phages targeting Salmonella can potentially lyse phylogenetically related genera, such as Escherichia coli or Citrobacter spp ( Lorenzo-Rebenaque et al, 2021 ; Zhao et al, 2022 ). Different challenge experiments in poultry have revealed the efficacy of bacteriophage therapy application to control enteric pathogens ( Carvalho et al, 2010 ; Nabil et al, 2018 ; Sevilla-Navarro et al, 2018 ; Clavijo et al, 2019 ; Richards et al, 2019 ; Huang et al, 2022 ).…”

“…Likewise, further research into crucial parameters that influence the success of phage interventions is needed to reach a consensus on the impact of bacteriophage therapy in the gut ( Javaudin et al, 2021 ). In poultry, the data on the effects of phage treatment on dysbiotic events in gut microbiota are scarce ( Clavijo et al, 2022 ; Zhao et al, 2022 ). Thus, before making any decisions on the use of phage as a therapy, our knowledge of phage-host interactions must be increased ( Sutton and Hill, 2019 ).…”

“…Accordingly, a logical first step in exploring the safety of phage therapy would be to rule out that dysbiotic changes in the gut microbial community occur. Despite its ubiquity in the environment and its narrow range of action, the introduction of therapeutic phages to the microbiota will still act as an external agent ( Hsu et al, 2019 ; Clavijo et al, 2022 ; Zhao et al, 2022 ). In this way, a recent report demonstrated that Salmonella phages induce changes in the intestinal microbiota of Salmonella -free chicks at early life stages ( Zhao et al, 2022 ).…”