Co-housing with Tibetan chickens improved the resistance of Arbor Acres chickens to Salmonella enterica serovar Enteritidis infection by altering their gut microbiota composition

Abstract

Background: Salmonella enterica serovar Enteritidis (S. Enteritidis) is a global foodborne pathogen that poses a significant threat to human health, with poultry being the primary reservoir host. Therefore, addressing S. Enteritidis infections in poultry is crucial to protect human health and the poultry industry. In this study, we investigated the effect of co-housing Arbor Acres (AA) chickens, a commercial breed susceptible to S. Enteritidis, with Tibetan chickens, a local breed resistant to S. Enteritidis infection, on the resistance of the latter to the pathogen.

Results: Ninety-six 1-day-old Tibetan chickens and 96 1-day-old AA chickens were divided into a Tibetan chicken housed alone group (n = 48), an AA chicken housed alone group (n = 48), and a co-housed group (48 birds from each breed for 2 cages). All birds were provided the same diet, and the experimental period lasted 14 d. At d 7, all chickens were infected with S. Enteritidis, and samples were collected at 1-, 3-, and 7-day-post-infection. We found that the body weight of AA chickens significantly increased when co-housed with Tibetan chickens at 1- and 3-day-post-infection (P < 0.05). In addition, the cecal S. Enteritidis load in AA chickens was significantly reduced at 1-, 3-, and 7-day-post-infection (P < 0.05). Furthermore, the inflammatory response in AA chickens decreased, as evidenced by the decreased expression of pro-inflammatory cytokines NOS2, TNF-α, IL-8, IL-1β, and IFN-γ in their cecal tonsils (P < 0.05). Co-housing with Tibetan chickens significantly increased the height of villi and number of goblet cells (P < 0.05), as well as the expression of claudin-1 (P < 0.05), a tight junction protein, in the jejunum of AA chickens. Further analysis revealed that co-housing altered the gut microbiota composition in AA chickens; specifically, the relative abundances of harmful microbes, such as Intestinimonas, Oscillibacter, Tuzzerella, Anaerotruncus, Paludicola, and Anaerofilum were reduced (P < 0.05).

Conclusions: Our findings indicate that co-housing with Tibetan chickens enhanced the resistance of AA chickens to S. Enteritidis infection without compromising the resistance of Tibetan chickens. This study provides a novel approach for Salmonella control in practical poultry production.

Keywords: Salmonella enterica serovar Enteritidis; Arbor Acres chicken; Co-housing; Gut microbiota; Tibetan chicken.

Fig. 1

Experimental design flow chart. Three groups were created for the experiment: AA chickens housed alone, Tibetan chickens housed alone, and AA chickens and Tibetan chickens co-housed at a 1:1 ratio. The experiment was conducted over 14 d. From d 1 to 6, the chickens are fed normally. On d 7, they are orally inoculated with S. Enteritidis. Samples were collected on 1, 3, and 7 d-post-infection

Fig. 2

Co-housing with Tibetan chickens improved the ability of AA chickens to resist S. Enteritidis infection. A–F Bodyweight (A), liver index (B), and spleen index (C), and S. Enteritidis loads in the liver (D), spleen (E), and cecum chyme (F). Data were analyzed by an independent sample t-test and are presented as the mean ± standard error of the mean (SEM) (n = 8–10). ^*P < 0.05

Fig. 3

Co-housing with Tibetan chickens alleviated inflammation in AA chickens infected with S. Enteritidis. A–F Relative expression of genes coding for pro-inflammatory cytokines:; NOS2 (A), TNF-α (B), IL-8 (C), IL-1β (D), IL-10 (E), and IFN-γ (F) in the cecal tonsils. Data were analyzed by an independent sample t-test and are presented as the mean ± SEM (n = 6). ^*P < 0.05

Fig. 4

Co-housing with Tibetan chickens improved intestinal morphology and barrier function in AA chickens infected with S. Enteritidis. A–D The morphology of the jejunum (A), villus height (B), crypt depth (C), and ratio of villus height-to-crypt depth (VCR) (D). E and F Goblet cells of the jejunum) and number of goblet cells of per villus. G–J Relative expression of claudin-1 (G), MUC2 (H), occludin (I), and ZO-1 (J) in the jejunum. Data were analyzed by an independent sample t-test and are presented as the mean ± SEM (n = 6). ^*P < 0.05

Fig. 5

Co-housing with Tibetan chickens changed the diversity and composition of gut microbiota in AA chickens infected with S. Enteritidis. A and B Beta diversity analyzed by PCoA (A) and NMDS (B). C Column chart of top 40 bacteria at the genus level. D and E LEfSe analysis of cecum microbiota among the groups Tibetan chicken + S. Enteritidis and co-housed Tibetan chicken + S. Enteritidis (D) and AA chicken + S. Enteritidis and co-housed AA chicken + S. Enteritidis (E). Red bars are taxa enriched in the co-housed Tibetan chicken + S. Enteritidis or AA chicken + S. Enteritidis groups, green bars are taxa enriched in Tibetan chicken + S. Enteritidis and co-housed AA chicken + S. Enteritidis groups. Only taxa with a linear discriminant analysis (LDA) value > 3.2 are depicted. F–P Top 40 differential bacteria at the genus level; Intestinimonas (F), Ruminococcus torques group (G), CHKCI001 (H), Fournierella (I), Oscillibacter (J), Tuzzerella (K), UCG-005 (L), Anaerotruncus (M), Paludicola (N), Anaerofilum (O), Ruminococcus gnavus group (P). Data were analyzed by an independent sample t-test and are presented as the mean ± SEM (n = 6). ^*P < 0.05

Fig. 6

Correlation analysis between different indices and microorganisms in the top 40 genera in the chickens. ^*P < 0.05 and ^**P < 0.01 (following Spearman’s correlation analysis)