the effect of tannins in grape pomace and oak leaf on the in vitro organic matter digestibility andin situ disappearance of sheep

the effect of grape pomace (vitis vinifera) and in oak leaf (quercus libani) tannins by three runs of in vitro gas production on the organic matter digestibility (omd) and in situ dry matter (dm) and crude protein (cp) disappearance were studied in four sheeps. polyethylene glycol (peg) was used to deactivate the tannins. in vitro gas production was recorded at 2, 4, 6, 8, 12, 48, 72, 96 and 120 h of incubation. the chemical composition (g/kg dm) of grape pomace and oak leaf were 940, 940 organic matter (om); 94, 116 crude protein (cp); 568, 515 neutral detergent fiber (ndfom); 467, 316 acid detergent fiber (adfom); 242, 93; (lignin (sa)); 70.5, 82 total phenols (tp); 49.7, 73 total tannins (tt); 79, 5.4 condensed tannin (ct) and 40, 70 hydrolysable tannin (ht). using grape pomace and oak leaf decreased omd, short chain fatty acids (scfa), insoluble but fermentable fraction (b) and fermentation rate (c) comparing to control (p