Determining of Digestibility and Palatability of White and Red Grape Pomace in Sheep

This study was conducted to determine the digestibility and palatability of white and red grape pomace. Experimental feedstuffs were analyzed chemically, and phenol concentration was determined. Then the feeds digestibility measured in vivo and in vitro and their palatability was tested. Four adult male sheep with 40±1.2 kg body weight were used in these experiments. Red and white grape pomaces replaced with alfalfa hay with proportion of 50:50 to determine the digestibility. The results showed that red grape pomace had more phenol and tannin concentration than those of white grape pomace, thus, reduction of protein concentration, digestibility and metabolizable energy of red grape pomace was expectable. Nutrients digestibility of basal diet including alfalfa hay was significantly (P<0.01) higher than experimental feeds. It may be due to higher concentration of tannin, lignin and neutral detergent fiber in grape pomaces. Lower digestibility of red grape pomace may be attributed to higher tannin concentration in this pomace. Palatability of basal ration (alfalfa) was lower than pomaces. Palatability of white grape pomace (45.5%) was higher than that of red grape pomace (38.16%) (P<0.01). It may conclude that grape pomace can be considered as a good source of fiber and may use in diets of low yielding animals to meet the requirements of energy and nitrogen. For increasing nutritive value of grape pomace, it may be better to use chemical treatment and physical processing of such as ensiling, drying and addition poly ethylene glycol which needs more investigation to be done.