In Vivo Recovery of Bacteriophages and Their Effects on Clostridium perfringens-Infected Broiler Chickens

Abstract

The objectives of this study were to recover bacteriophages (BPs) from the intestinal digesta of BP-fed broilers and to evaluate the antibacterial effects of encapsulated or powdered BPs in broiler chickens challenged with Clostridium perfringens. Day-old broiler chicks (n = 320/experiment) were randomly assigned to 32 pens (n = 10 broilers/pen) and allocated to one of four dietary groups: (1) unchallenged group (NEG); (2) C. perfringens-challenged group (POS); (3) POS group fed a diet supplemented with powdered BPs; and (4) POS group fed a diet supplemented with encapsulated BPs. On days 21, 22, and 23 post-hatch, all chickens except NEG were orally inoculated twice a day with 2 mL C. perfringens (1.0 × 10⁸ cfu/mL). Varying BP levels were detected in gut digesta at all ages and were numerically or significantly higher in the encapsulated BP group than in the powdered BP group. Dietary powder or encapsulated BPs reversed the C. perfringens-mediated increase in crypt depth. In addition, villus height to crypt depth ratio was elevated in the NEG and BP-treated/challenged groups compared with that in the POS group. C. perfringens counts in the cecum were significantly lower in the BP-fed chickens than in the POS group. The encapsulated BP-supplemented diet-fed chickens had the highest serum IgA levels. Collectively, our results suggest that dietary BP remains viable in intestinal digesta upon ingestion and can inhibit cecal C. perfringens counts.

Keywords: Clostridium perfringens; bacteriophage; broiler chicken; gut health.

Figure 1

Experimental scheme. Broiler chicks were fed a control or bacteriophage (BP)-added diet for 28 d. On d 21, 22, and 23, half of the control group and BP-added diet-fed groups were orally inoculated with Clostridium perfringens. On d 1, 7, and 14, one bird per group (n = 8/group) was randomly sampled for BP isolation in gut digesta. On d 1 post C. perfringens challenge, one bird per group (n = 8/group) was sampled for gut lesion, C. perfringens counts, ileal morphology, cecal short-chain fatty acid (SCFA) contents, and serum biochemistry. On d 2 post C. perfringens challenge, one bird per group (n = 8/group) was sampled for gut lesion and C. perfringens counts.

Figure 2

Viable BP levels in various segments of gastrointestinal tract. (A) Crop, (B) gizzard, (C) jejunum, and (D) cecum. Day-old broiler chickens were fed diets with or without encapsulated and powder BPs and sacrificed on different days for sampling gut digesta. Viable BPs (Y-axis) in figures are presented in log₁₀ (pfu/g of digesta). Error bars represent the standard deviation of the mean. BPs were not detected in the no-BP-added diet-fed chickens (data not shown). Asterisks denote the significant differences in BP levels between the encapsulated and powder BP groups at the 0.05 level. NA = not assayed, ND = not detected.