EFFECT OF A DAILY SUPPLEMENTATION OF POLYETHYLENE-GLYCOL ON INTAKE AND DIGESTION OF TANNIN-CONTAINING LEAVES (CERATONIA-SILIQUA) BY SHEEP

The nutritional value of carob leaves (CL) and the effectiveness of in creasing amounts (12.5, 25, 32, and 50 g/day) of polyethylene glycol 4 000 (PEG) supplemented once daily in overcoming the negative effect of tannins in carob leaves, were examined in four Merino ewes. Ewes fed solely CL were not able to sustain their body weights, and excreted in feces more protein than was consumed; the digestibility of cell walls was very low (220 g/kg). Supplementation with 25 g/day PEG increased digestible organic matter intake by 2-fold. This increase was associat ed with a marked improvement in protein and cell wall digestibility an d recovery of weight loss. The present results provide evidence for th e first time that condensed tannins may induce a marked depressive eff ect on the intestinal activity of trypsin and amylase in ruminating an imals (as indicated by their activity in fecal samples).