Clay Scofield

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Publications (2)7.51 Total impact

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    Article: Alteration of the Ileal Microbiota of Weanling Piglets by the Growth-Promoting Antibiotic Chlortetracycline
    Elizabeth Rettedal, Sébastien Vilain, Stacy Lindblom, Kelly Lehnert, Clay Scofield, Sajan George, Sharon Clay, Radhey S Kaushik, Artur J M Rosa, David Francis, Volker S Brözel
    [show abstract] [hide abstract]
    ABSTRACT: Antibiotics such as chlortetracycline (CTC) have been used to promote growth of pigs for decades, but concerns over increased antibiotic-resistant infections in humans have prompted the development of alterna-tive strategies. Developing alternatives to antibiotic growth promoters (AGPs) could be informed by informa-tion on the mechanisms of growth promotion, notably, how AGPs affect the microbial populations of the gastrointestinal tract. Pigs from three sows were aseptically delivered by cesarean section. Six piglets were distributed to each of two foster mothers until weaning, when piglets were fed a diet with or without 50 mg/kg CTC for 2 weeks. The ileal bacterial microbiota was characterized by using a cultivation-independent approach based on DNA extraction, PCR amplification, cloning, and sequencing of the 16S rRNA gene pool. The ileal and mucosal communities of these growing pigs were dominated by Lactobacillus bacteria, various members of the family Clostridiaceae, and members of the poorly known genus Turicibacter. Overall, CTC treatment resulted in three shifts: a decrease in Lactobacillus johnsonii, an increase in L. amylovorus, and a decrease in Turicibacter phylotypes. The composition of the microbiota varied considerably between individual pigs, as revealed by shared operational taxonomic units (OTUs) and similarity (SONS) analysis (YC values). While the observed variation between untreated pigs obscured the possible effect of CTC, -LIBSHUFF and SONS analyses of pooled libraries indicated a significant shift due to CTC in both the lumen and the mucosa, with some OTUs unique to either treated or control ileum. DOTUR analysis revealed little overlap between control and treated communities at the 3% difference level, indicating unique ileal communities in the presence of CTC. Antibiotics have been used to promote animal growth for over 50 years. Antibiotic growth promoters (AGPs) such as tylosin, bacitracin, virginiamycin, and chlortetracycline (CTC) have been fed to pigs, chickens, and other animals to promote growth through increased feed intake, weight gain, and im-proved herd health (7, 36). Use of AGPs has come under increasing pressure with the growing consensus that their use leads to increased antibiotic-resistant infections in humans via generation of reservoirs of antibiotic-resistant bacteria that may enter the food chain through contamination (38, 46). The increasing concerns about antibiotic resistance have raised questions about whether the potential risks are worth the beneficial effects (44). Development of non-antibiotic-based alternative strategies to promote animal growth may benefit through increased understanding of AGP mecha-nisms of growth promotion. The growth-promoting impact of antibiotics was first de-scribed in the 1940s, and their use soon became routine (29, 35). The gastrointestinal (GI) tract harbors a great diversity of bacteria at a very high density (27). The increased growth and
    Applied and Environmental Microbiology 10/2009; 75:5489-5495. · 3.83 Impact Factor
  • Article: Alteration of the ileal microbiota of weanling piglets by the growth-promoting antibiotic chlortetracycline.
    Elizabeth Rettedal, Sébastien Vilain, Stacy Lindblom, Kelly Lehnert, Clay Scofield, Sajan George, Sharon Clay, Radhey S Kaushik, Artur J M Rosa, David Francis, Volker S Brözel
    [show abstract] [hide abstract]
    ABSTRACT: Antibiotics such as chlortetracycline (CTC) have been used to promote growth of pigs for decades, but concerns over increased antibiotic-resistant infections in humans have prompted the development of alternative strategies. Developing alternatives to antibiotic growth promoters (AGPs) could be informed by information on the mechanisms of growth promotion, notably, how AGPs affect the microbial populations of the gastrointestinal tract. Pigs from three sows were aseptically delivered by cesarean section. Six piglets were distributed to each of two foster mothers until weaning, when piglets were fed a diet with or without 50 mg/kg CTC for 2 weeks. The ileal bacterial microbiota was characterized by using a cultivation-independent approach based on DNA extraction, PCR amplification, cloning, and sequencing of the 16S rRNA gene pool. The ileal and mucosal communities of these growing pigs were dominated by Lactobacillus bacteria, various members of the family Clostridiaceae, and members of the poorly known genus Turicibacter. Overall, CTC treatment resulted in three shifts: a decrease in Lactobacillus johnsonii, an increase in L. amylovorus, and a decrease in Turicibacter phylotypes. The composition of the microbiota varied considerably between individual pigs, as revealed by shared operational taxonomic units (OTUs) and similarity (SONS) analysis (theta(YC) values). While the observed variation between untreated pigs obscured the possible effect of CTC, integral-LIBSHUFF and SONS analyses of pooled libraries indicated a significant shift due to CTC in both the lumen and the mucosa, with some OTUs unique to either treated or control ileum. DOTUR analysis revealed little overlap between control and treated communities at the 3% difference level, indicating unique ileal communities in the presence of CTC.
    Applied and environmental microbiology 08/2009; 75(17):5489-95. · 3.69 Impact Factor
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