Molecular ecological analysis of porcine ileal microbiota responses to antimicrobial growth promoters

• Published in: Journal of animal science Vol. 81; no. 12; pp. 3035 - 3045
• Main Authors: Collier, C.T, Smiricky-Tjardes, M.R, Albin, D.M, Wubben, J.E, Gabert, V.M, Deplancke, B, Bane, D, Anderson, D.B, Gaskins, H.R
• Format: Journal Article
• Language: English
• Published: Savoy, IL Am Soc Animal Sci 01-12-2003; American Society of Animal Science
• Subjects: animal growth; Animal productions; Animal, plant and microbial ecology; Animals; Anti-Bacterial Agents - administration & dosage; bacteria; Bacteria - drug effects; Bacteria - genetics; barrows; Biological and medical sciences; carbadox; denaturing gradient gel electrophoresis; diet; DNA, Bacterial - analysis; DNA, Bacterial - genetics; DNA, Ribosomal - analysis; DNA, Ribosomal - genetics; Ecosystem; Electrophoresis, Agar Gel - methods; Electrophoresis, Agar Gel - veterinary; Fundamental and applied biological sciences. Psychology; growth promotion; ileum; Ileum - drug effects; Ileum - microbiology; immune response; Lactobacillus; lincomycin; Male; Microbial ecology; Normal microflora of man and animals. Rumen; nutrient requirements; Polymerase Chain Reaction - methods; Polymerase Chain Reaction - veterinary; quantitative polymerase chain reaction; Random Allocation; ribosomal DNA; RNA, Ribosomal, 16S - analysis; sequence analysis; Species Specificity; Streptococcus; sulfathiazole; Swine - growth & development; Swine - microbiology; Terrestrial animal productions; Time Factors; tylosin; Vertebrates; virginiamycin; Monogastric animal; Lactic acid bacteria; Bacillaceae; Bacitracin; Microbiota; Meat animals; Bacillales; Intestine; Bacillus; Penicillin; 16S-RNA; Bacteria; Lactobacillaceae; Micrococcales; Associated microflora; Tylosin; Ungulata; Lactobacillus; Farming animal; Gel electrophoresis; 16S rDNA Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis; Ecology; Experimental study; Quantitative Polymerase Chain Reaction; Ileum; Pig; Polymerase chain reaction; Streptococcaceae; Vertebrata; Mammalia; Analysis method; Streptococcus; Treatment; Virginiamycin; Diet; Antibiotics; DNA; Artiodactyla; Carbadox
• ISSN: 0021-8812; 1525-3163
• DOI: 10.2527/2003.81123035x

Cultivation-independent microbial molecular ecology approaches were used to examine the effects of antibiotic growth promoters on the pig ileal microbiota. Five-week-old barrows were fitted with a simple T-cannula at the distal ileum. Three diets meeting or exceeding the minimum nutrient requirements were fed for 5 wk and supplemented as follows: 1) negative control (no antibiotic; n = 5), 2) continuous tylosin administration (n = 5), and 3) an antibiotic rotation sequence (wk 1, chlorotetracycline sulfathiazole penicillin; wk 2, bacitracin and roxarsone; wk 3, lincomycin; wk 4, carbadox; wk 5, virginiamycin; n = 5). Ileal luminal contents were collected for DNA isolation at the end of each of the 5 wk of the testing period. The V3 region of 16S rDNA was amplified by PCR and analyzed via denaturing gradient gel electrophoresis (DGGE) and quantitative polymerase chain reaction (qPCR). Resulting PCR-DGGE band numbers (bacterial species) were counted, and the banding patterns analyzed by calculating Sorenson’s pairwise similarity coefficients (Cs), an index measuring bacterial species in common among samples. Band numbers and total bacterial DNA concentrations decreased (P < 0.05) temporally in antibiotic-treated pigs compared with controls. Comparisons between treatments yielded low intertreatment Cs indices, indicating treatment-dependent alterations in banding patterns, whereas intratreatment comparisons revealed increased homogeneity in antibiotic-treated vs. control pigs. Sequence analysis of treatment-specific bands identified three Lactobacillus, one Streptococcus, and one Bacillus species that were diminished with antibiotic rotation treatment, whereas tylosin selected for the presence of L. gasseri. Lactobacillus-specific qPCR was performed and analyzed as a percentage of total bacteria to further evaluate the effects of antibiotic administration on this genus. Total bacteria were decreased (P < 0.05) by tylosin and rotation treatments, whereas the percentage of lactobacilli increased (P < 0.05) by d 14 and through d 28 in tylosin-treated pigs. The decrease in total bacteria by antibiotics may reduce host-related intestinal or immune responses, which would divert energy that could otherwise be used for growth. Conversely, the ability of tylosin to improve animal growth may relate to its apparent selection for lactobacilli, commensals known to competitively exclude potentially pathogenic species from colonizing the intestine.