| Influence of chlortetracycline and dietary protein level on visceral organ mass of growing beef steers. | |
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MedLine Citation:
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PMID: 11132831 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Thirty-two beef steers (285 +/- 3 kg BW) were used to determine the effects of chlortetracycline and dietary protein level on visceral tissue mass, chemical composition, intestinal morphology, and proliferation rate indices. Steers were allotted randomly by weight to a factorial arrangement of dietary treatments consisting of either 10 or 13% CP diets top-dressed with a corn meal carrier (500 g/d) containing either 0 or 350 mg of chlortetracycline. After 84 d, steers were slaughtered and visceral organs removed and separated. Rinsed wet tissue mass was recorded; total RNA, total DNA, tissue DM, and tissue N content were determined; and tissue sections were prepared for immunohistochemical analysis. Thin tissue sections were evaluated to determine crypt depth and villus height as well as proliferation rate by immunohistochemical detection of the nuclear antigen Ki67. Rumen and abomasum weights and small intestinal length were greater (P < 0.04) in steers fed the 13% CP diet than in those fed the 10% CP diet on both an absolute weight basis and a percentage of empty BW. Chemical composition of the small intestinal and ruminal segments were largely unaffected by increased dietary protein. Increasing the dietary CP also increased the villus height in duodenal (P = 0.02) and the crypt depth of jejunal (P = 0.03) sections. Dietary administration of chlortetracycline decreased (P < 0.01) small intestinal weight both on absolute and empty BW bases. Nitrogen and RNA concentrations of the small intestinal segments were unaffected (P > 0.1) by dietary administration of subtherapeutic levels of chlortetracycline; however, because of increases (P < 0.05), or tendencies for an increase (P < 0.1), in the tissue content of DNA, the ratio of N to DNA was decreased (P < 0.05) or tended to be decreased (P < 0.1) in the small intestinal segments of the chlortetracycline-treated animals. The observed decrease in small intestinal epithelial mass does not appear to be due to alterations in cell proliferation rate but rather cell size. Consistent with this finding, cell proliferation, as determined by Ki67 antigen staining, was not affected by dietary treatment. Chlortetracycline administration decreased small intestinal mass that may be a result of decreased cell size. |
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Authors:
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R L Baldwin; K R McLeod; T H Elsassert; S Kahl; T S Rumsey; M N Streeter |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Journal of animal science Volume: 78 ISSN: 0021-8812 ISO Abbreviation: J. Anim. Sci. Publication Date: 2000 Dec |
Date Detail:
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Created Date: 2000-12-29 Completed Date: 2001-03-15 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 8003002 Medline TA: J Anim Sci Country: United States |
Other Details:
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Languages: eng Pagination: 3169-76 Citation Subset: IM |
Affiliation:
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Nutrient Conservation and Metabolism Laboratory, Livestock and Poultry Sciences Institute, ARS, USDA, Beltsville, MD 20705-2350, USA. rbaldwin@lpsi.barc.usda.gov |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Administration, Oral Animals Body Weight / drug effects Cattle / growth & development* Cell Division / drug effects Chlortetracycline / administration & dosage, pharmacology* Dietary Proteins / administration & dosage, pharmacology* Enterocytes / cytology, drug effects Male Random Allocation Viscera / drug effects, growth & development* |
| Chemical | |
Reg. No./Substance:
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0/Dietary Proteins; 57-62-5/Chlortetracycline |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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