Broad host range phages target global Clostridium perfringens bacterial strains and clear infection in five-strain model systems.

Clostridium perfringens is a prevalent bacterial pathogen in poultry, and due to the spread of antimicrobial resistance, alternative treatments are needed to prevent and treat infection. Bacteriophages (phages), viruses that kill bacteria, offer a viable option and can be used therapeutically to treat C. perfringens infections. The aim of this study was to isolate phages against C. perfringens strains currently circulating on farms across the world and establish their virulence and development potential using host range screening, virulence assays, and larva infection studies. We isolated 32 phages of which 19 lysed 80%-92% of our global C. perfringens poultry strain collection (n = 97). The virulence of these individual phages and 32 different phage combinations was quantified in liquid culture at multiple doses. We then developed a multi-strain C. perfringens larva infection model, to mimic an effective poultry model used by the industry. We tested the efficacy of 16/32 phage cocktails in the larva model. From this, we identified that our phage cocktail consisting of phages CPLM2, CPLM15, and CPLS41 was the most effective at reducing C. perfringens colonization in infected larvae when administered before bacterial challenge. These data suggest that phages do have significant potential to prevent and treat C. perfringens infection in poultry. IMPORTANCE: Clostridium perfringens causes foodborne illness worldwide, and 95% of human infections are linked to the consumption of contaminated meat, including chicken products. In poultry, C. perfringens infection causes necrotic enteritis, and associated mortality rates can be up to 50%. However, treating infections is difficult as the bacterium is becoming antibiotic-resistant. Furthermore, the poultry industry is striving toward reduced antibiotic usage. Bacteriophages (phages) offer a promising alternative, and to progress this approach, robust suitable phages and laboratory models that mimic C. perfringens infections in poultry are required. In our study, we isolated phages targeting C. perfringens and found that many lyse C. perfringens strains isolated from chickens worldwide. Consistent with other published studies, in the model systems we assayed here, when some phages were combined as cocktails, the infection was cleared most effectively compared to individual phage use.

Xylanase, and the role of digestibility and hindgut fermentation in pigs on energetic differences among high and low energy corn samples1.

The experimental objective was to evaluate the digestibility and fermentation differences between high and low energy corn samples and their response to xylanase supplementation. Four corn samples, 2 with higher DE content (HE-1 and HE-2; 3.74 and 3.75 Mcal DE/kg DM, respectively) and 2 with a lower DE content (LE-1 and LE-2; 3.63 and 3.56 Mcal DE/kg DM, respectively) were selected based upon a previous digestibility trial. Sixteen individually housed barrows (PIC 359 × C29; initial BW = 34.8 ± 0.23kg) were surgically fitted with an ileal T-cannula and randomly allotted to treatments in an 8 × 4 Youden square design. Dietary treatments were arranged in a 4 × 2 factorial: HE-1, HE-2, LE-1, and LE-2, with and without xylanase supplementation. Diets were formulated using one of the 4 corn samples, casein, vitamins, minerals, and 0.4% chromic oxide as an indigestible marker. Feed intake was established at approximately 3 times the estimated energy required for maintenance (NRC 2012) based upon the average initial BW of the pigs at the start of each collection period, which consisted of 9 d adaptation, 2 d of fecal, and 3 d of ileal collections. Diets, ileal, and fecal samples were analyzed for DM, GE, and total dietary fiber (TDF), to determine apparent total tract (ATTD), hindgut fermentation (HF), apparent ileal digestibility (AID) coefficients. A diet × enzyme interaction was not observed for any of the measured variables (P > 0.10). The HE-1 and HE-2 diets had greater ATTD of GE, and HE-2 diet had greater ATTD of DM (P < 0.001 and P = 0.007, respectively). Xylanase, independent of diet, improved the ATTD of GE and DM (84.8 vs. 83.6% for GE with and without enzyme, respectively, P = 0.008; and 84.2 and 83.0% with and without enzyme, respectively, P = 0.007). The energetic differences among these corn samples appeared to be driven by fermentability in the hindgut. Supplementing xylanase improves digestibility irrespective of the digestibility energy content of corn.

Xylanase, protease and superdosing phytase interactions in broiler performance, carcass yield and digesta transit time.

The interaction of xylanase, protease and superdosing (1,500 FTU/kg) phytase in a 2 × 2 × 2 factorial arrangement was studied in broilers fed sorghum-based diets. A total of 2,800 one-day-old unsexed Ross 308 chicks were housed in 56 pens with 50 birds per pen, with or without inclusion of xylanase, protease and phytase, totaling 8 treatments and 7 replicates per treatment. Body weight (BW) and feed intake (FI) were measured at 21 and 42 days of age, and mortality corrected feed conversion ratio (FCR) was calculated for each period and cumulatively. Tibia ash and carcass yield were determined in 2 birds per replicate at 21 and 42 days of age, respectively. Digesta transit time was determined at 21, 28, 35 and 42 days of age using 5 birds per replicate. Results showed that superdosing phytase increased BW and FI at 42 days of age (P < 0.05) and xylanase improved FCR (P < 0.05). Xylanase and phytase also positively influenced carcass yield and breast weight, respectively. Overall, inclusion of superdosing phytase increased transit time when included in a diet containing xylanase, and no change with protease inclusion. In conclusion, the beneficial effects of xylanase, protease and superdosing phytase in broiler performance were not additive. This limitation is likely not related to the lack of efficacy of any one of the individual enzymes but to a limitation of the bird to respond additively to successive additions of enzymes.