Influence of a three-day feed and water deprivation period on gut fill, tissue weights, and tissue composition in mature wethers.

Fourteen mature wethers (average BW 71.8 +/- .86 kg) were used to study the effects of feed and water deprivation on the quantity and composition of gastrointestinal tract (GIT) contents and tissues. Sheep (seven/treatment) were randomly assigned to one of two treatments: 1) limit fed 1,400 g/d of a pelleted diet or 2) deprived of feed and water for 3 d. Before euthanasia, sheep were infused i.v. with Evans blue, sodium thiocyanate, and antipyrine to determine plasma, extracellular, and total body water, respectively. Blood samples were obtained for 4 h after the infusions. Sheep were killed by injection of a lethal dose of a general anesthetic and organs were immediately removed, weighed, and sampled. Compared with controls, unfed sheep lost 7.1 kg (9.9%; P < .05) of their BW during the 3-d deprivation period, of which 21.1% was from the stomach contents, 28.1% (P < .05) was from the GIT (stomach + intestine) contents, and 6.7% (P < .02) was from GIT tissues. The weight loss of the liver, lungs, heart, and kidneys each accounted for less than 1% of the total weight loss. Of the total weight loss, 80% (P < .09) was body water. Of total body water loss, 57% (P < .20) was from the intracellular compartment and 29% (P < .06) was from the GIT contents. Total Ca, Na, Mg, Cu, Fe, and Zn losses via fecal + urinary excretion were less or equal to losses from the GIT contents.(ABSTRACT TRUNCATED AT 250 WORDS)