Abstract
Four Dorset wethers were studied in a Latin square design with 72-h periods to determine the metabolic adaptations that occur in support of increased glucose demand in ruminants. Wethers injected at 8-h intervals with excipient or a total of .5, 1.0, or 2.0 g/d of phlorizin excreted an average of 0, 72.7, 97.9, and 98.5 g/d of glucose into the urine, respectively. Both acute (2 to 24 h after the first injection) and chronic (8-h intervals from 8 to 72 h after the first injection) adaptations of plasma variables to phlorizin treatment were assessed. Concentrations of plasma glucose decreased linearly with increasing phlorizin dose during the 1st 24 h of treatment and tended to decrease linearly with phlorizin dose during 8 to 72 h of treatment. Urea N tended to increase linearly during 2 to 24 h and increased linearly during 8 to 72 h. Nonesterified fatty acids increased linearly with phlorizin injection during the entire treatment period. β-Hydroxybutyrate increased quadratically with phlorizin injection during 2 to 24 h and tended to increase quadratically during 8 to 72 h. The ratio of insulin to glucagon tended to decrease linearly with phlorizin injection during the 1st 24 h but was unaffected from 8 to 72 h. Triiodothyronine, but not thyroxine, tended to decrease linearly with phlorizin injection during 8 to 72 h. Cortisol was not affected by treatment. Digestibilities of energy and N were not affected by treatment. Urinary energy excretion increased with phlorizin injection in proportion to the amounts of glucose excreted into the urine. These data indicate that phlorizin-treated wethers largely adapted to phlorizin treatment by 24 h after the first injection and are a suitable model for further investigations of hepatic adaptation to increased glucose demand in ruminants.
Original language | English (US) |
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Pages (from-to) | 2938-2946 |
Number of pages | 9 |
Journal | Journal of animal science |
Volume | 76 |
Issue number | 11 |
DOIs | |
State | Published - 1998 |
Keywords
- Glucose
- Metabolism
- Phlorizin
- Ruminants
ASJC Scopus subject areas
- Food Science
- Animal Science and Zoology
- Genetics