EFFECTS OF FAUNATION, PROTEIN SOURCE AND SURGICAL MODIFICATION OF THE INTESTINAL TRACT UPON FLOWS OF CALCIUM, PHOSPHORUS AND MAGNESIUM IN THE DIGESTIVE TRACT OF SHEEP

Abstract

Effects of faunation and protein source, corn gluten meal (CGM) versus soybean meal (SBM) upon Ca, P and Mg in the digestive tract of sheep were evaluated. Twelve yearling rams with cannulae in the abomasum and terminal ileum, and with sections of the small intestine bypassed (no bypass, n = 4; proximal third, n = 4; a distal third, n = 4) were used. All sheep were verified afaunated (protozoa-free) from birth; all sheep were faunated for the last half of the experiment. Negative Ca balances were obtained: for afaunated (P < 0.01) relative to faunated sheep, with less (P < 0.01) Ca absorbed in the stomach section and more (P < 0.01) Ca secreted in the large intestine of afaunated sheep; and for SBM (P = 0.07) as opposed to CGM fed sheep, with less (P < 0.01) Ca absorbed in the stomach section of SBM sheep. With SBM fed, afaunated sheep, the Ca balance was the same as that measured in all proximal bypass sheep. Proximal bypass surgery had a minimal effect (0.10 > P > 0.05), while protein source had no (P > 0.05) influence upon P or Mg. Faunation influenced P secretion (P < 0.05) and Mg absorption (P < 0.05) in the stomach section, and P absorption (P < 0.05) in the small intestine. More dietary P (P < 0.05) and Mg (P < 0.01) was absorbed from the digestive tract of faunated than afaunated sheep. Key words: Sheep, faunation, calcium, phosphorus, magnesium, digestion