Effects of dietary supplementation of bacteriophage cocktail on health status of weanling pigs in a non-sanitary environment

Abstract

Background: The study evaluated the effects of bacteriophage cocktail (BP) and ZnO administered during weaning time for piglets exposed to a non-sanitary environment. The bacteriophages were designed to eliminate Escherichia coli (K88, K99 and F41), Salmonella (typhimurium and enteritidis), and Clostridium perfreingens (types A and C). Forty 21-day-old crossbreed piglets were assigned to four treatments, including the PC (sanitary environment), NC (non-sanitary environment), BP (NC plus 10⁸ pfu/kg BP), and ZO (NC plus 2,500 mg/kg ZnO). Piglets in the NC, BP and ZO were kept in a non-sanitary environment for 14 d, which was contaminated with the feces of infected pigs.

Results: Pigs in the BP and ZO treatments had a higher final body weight compared with the NC. The NC treatment showed the highest concentration of inflammatory cytokines including interleukin (IL)-1β, IL-6 and tumor necrosis factor-α in the plasma. The administration of BP and ZO showed lower myeloperoxidase concentrations compared with the NC. The NC treatment showed a lower concentration of superoxide dismutase in serum compared with the PC. Among the treatments in non-sanitary environment, the NC treatment showed a higher concentration of malondialdehyde compared with the ZO. The PC treatment showed a lower concentration of butyric acid in the feces compared with the BP treatment. Among non-sanitary treatments, the villus height in the duodenum was greater in the BP and ZO compared with the NC. The lower abundance of Proteobacteria phylum was observed in the BP and PC treatments compared with the NC. The highest relative abundance of Eubacterium was recorded in the BP treatment. The abundance of Megasphaera and Schwartzia was higher in the NC pigs compared with the BP piglets. The abundance of Desulfovibrio was lower in the supplemented treatments (BP and ZO) compared with non-supplemented (NC and PC). The abundance of Cellulosilyticum genera was higher in the BP and ZO treatments rather than in the NC. The piglets in the NC treatment had the highest abundance of Escherichia-Shigella, followed by the PC and ZO treatments.

Conclusion: In conclusion, these results suggest that the supplementation of bacteriophage cocktail could effectively control Proteobacteria phylum, Clostridium spp. and coliforms population and mitigated the adverse influences of weaning stress in piglets.

Keywords: Antioxidant; Cytokines; Diarrhea; Fecal score; Inflammation; Microbiota; Proteobacteria.

Fig. 1

Effects of bacteriophage cocktail or ZnO on blood cytokines and zonulin concentration of weaned pigs subjected to non-sanitary environment. PC, sanitary environment; NC, non-sanitary environment; BP, non-sanitary environment plus bacteriophage cocktail; ZO, non-sanitary environment plus 2,500 mg/kg ZnO. ^a,bDifferent letters indicate significant difference between groups (P < 0.05)

Fig. 2

Effects of bacteriophage cocktail or ZnO on inflammatory enzymes in the jejunum of weaned pigs subjected to non-sanitary environment. PC, sanitary environment; NC, non-sanitary environment; BP, non-sanitary environment plus bacteriophage cocktail; ZO, non-sanitary environment plus 2,500 mg/kg ZnO. ^a,bDifferent letters indicate significant difference between groups (P < 0.05)

Fig. 3

Effects of bacteriophage cocktail or ZnO on antioxidant status and liver-injury enzymes in the jejunum of weaned pigs subjected to non-sanitary environment. PC, sanitary environment; NC, non-sanitary environment; BP, non-sanitary environment plus bacteriophage cocktail; ZO, non-sanitary environment plus 2,500 mg/kg ZnO. ^a-cDifferent letters indicate significant difference between groups (P < 0.05)

Fig. 4

Alpha diversity of weaned pigs gut microbiota including total observed OTU (a), Shannon index (b), and phylogenetic diversity (PD) whole tree (c). PC, sanitary environment; NC, non-sanitary environment; BP, non-sanitary environment plus bacteriophage cocktail; ZO, non-sanitary environment plus 2,500 mg/kg ZnO. ^a,bDifferent letters indicate significant difference between groups (P < 0.05)

Fig. 5

Evaluation of beta diversity patterns of fecal microbial diversity in weaned pigs according to principal coordinate analysis of unweighted and Weighted Unifrac. PC, sanitary environment; NC, non-sanitary environment; BP, non-sanitary environment plus bacteriophage cocktail; ZO, non-sanitary environment plus 2,500 mg/kg ZnO

Fig. 6

Weaned piglets fecal bacterial community structure at the phylum level was identified by 16S rRNA gene analysis. PC, sanitary environment; NC, non-sanitary environment; BP, non-sanitary environment plus bacteriophage cocktail; ZO, non-sanitary environment plus 2,500 mg/kg ZnO

Fig. 7

Weaned piglets fecal bacterial community structure at the genus level was identified by 16S rRNA gene analysis. PC, sanitary environment; NC, non-sanitary environment; BP, non-sanitary environment plus bacteriophage cocktail; ZO, non-sanitary environment plus 2,500 mg/kg ZnO

Fig. 8

Weaned piglets fecal bacterial community structure at the species level was identified by 16S rRNA gene analysis. PC, sanitary environment; NC, non-sanitary environment; BP, non-sanitary environment plus bacteriophage cocktail; ZO, non-sanitary environment plus 2,500 mg/kg ZnO