title: Effect of dietary protein level on growth performance, indicators of enteric health, and gastrointestinal microbial ecology of weaned pigs induced with postweaning colibacillosis.
abstract: The effect of dietary CP level on performance, enteric health, and gastrointestinal microbial ecology of weaned pigs challenged with enterotoxigenic Escherichia coli (ETEC) K88 was investigated in a 14-d study. Forty weaned pigs (BW = 5.32 +/- 0.24 kg, mean +/- SD), housed 4 per pen, were randomly assigned to 2 diets (5 pens/diet): 1) 22.5% CP or 2) 17.6% CP supplemented with AA. Diets contained the same amount of ME and standardized ileal digestible Lys, Met + Cys, Thr, and Trp based on the ideal protein ratio. Isoleucine and Val were added to the 17.6% CP diet up to the level in the 22.5% CP diet. On d 8 postweaning, pigs were challenged with 6 mL of ETEC suspension (10(10) cfu/mL) by gavage. Feed disappearance and BW were measured on d 7, 9, 10, 12, and 14 for determination of ADG, ADFI, and G:F. One pig from each pen was serially slaughtered on -1, 3, and 7 d postchallenge (10 pigs/d of slaughter) to evaluate gut morphology, and gut microbial ecology and metabolites. Pigs fed the 22.5% CP diet had greater (P < 0.05) ADG and G:F than those fed the 17.6% CP diet before infection, but performance was similar between the 2 diets after ETEC challenge and overall. On d 3 after challenge, ETEC was not detected in the ileal digesta of pigs fed the 17.6% CP diet but was detected in the ileal digesta of 80% of pigs fed the 22.5% CP diet (5.22 +/- 1.07 cfu/g, mean +/- SD). Pigs fed the 17.6% CP diet had a greater (P < 0.01) prevalence of order Clostridiales (73 vs. 50%), family Lachnospiraceae (43 vs. 18%), and genus Roseburia (13 vs. 3%) in the colon digesta 7 d after challenge compared with those fed the 22.5% CP diet. The richness and diversity of bacteria in the colon digesta were less (P < 0.05) in pigs fed the 17.6% CP diet than in those fed the 22.5% CP diet at -1, 3, and 7 d postchallenge. Pigs fed the 22.5% CP diet had greater (P < 0.05) ammonia N concentration in the colon digesta on -1 and 7 d after challenge compared with those fed the 17.6% CP diet. Pigs fed the 22.5% CP diet had deeper (P < 0.05) crypts 1 d before challenge, shorter villi 3 d after challenge, and reduced villus height:crypt depth 1 d before and 3 d after challenge compared with those fed the 17.6% CP diet. In conclusion, a reduction in the dietary CP level of weaned pigs from 22.5 to 17.6% with AA supplementation impaired growth performance before, but not after, the ETEC challenge and increased the relative composition of butyrate producing bacteria in the colon digesta after ETEC challenge.
authors.affiliation: Department of Animal Science, University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: F O
authors.initials: FO
authors.lastname: Opapeju
authors.forename: D O
authors.initials: DO
authors.lastname: Krause
authors.forename: R L
authors.initials: RL
authors.lastname: Payne
authors.forename: M
authors.initials: M
authors.lastname: Rademacher
authors.forename: C M
authors.initials: CM
authors.lastname: Nyachoti
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002939:Ciprofloxacin / Q000494:pharmacology; D003967:Diarrhea / Q000382:microbiology / Q000662:veterinary; D004032:Diet / Q000662:veterinary; D004044:Dietary Proteins / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D004927:Escherichia coli Infections / Q000473:pathology / Q000517:prevention & control / Q000662:veterinary*; D005260:Female; D005766:Gastrointestinal Contents / Q000737:chemistry / Q000382:microbiology; D041981:Gastrointestinal Tract / Q000382:microbiology* / Q000473:pathology; D008297:Male; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology* / Q000473:pathology / Q000517:prevention & control; D014886:Weaning
chemical_list: D000900:Anti-Bacterial Agents; D004044:Dietary Proteins; D002939:Ciprofloxacin