This study was aimed to evaluate Correlation of in vitro gas production and in situ technique of tomato pomace degradability. Tomato pomace was obtained from five large factories and dried. Seeds and peels components were separated. In situ DM degradability was estimated for unground and ground (samples were ground through 2 mm screen) whole tomato pomace, seeds and peels components using the modified in situ polyester bag technique. Bags were incubated in the rumen of three fistulated steers fed ordinary diets. The bags were removed following 0, 2, 4, 8, 12, 24, 36, 48 and 72 h of incubation. In vitro gas production for the same components, with rumen liquor of same animals at same times, was measured. Regression model was made among the in situ and in vitro data by SAS 9.1. The degradability of whole pomace and its components showed that most of the DM was degraded after 24 h, although degradation increased up to 48 h but at a much lower rate. The grinding process was highly effective for improving the degradability measures for all samples especially seeds. The results of in vitro gas production after 72h incubation for grounds and unground pomace and compounds (229.74±7.8, 178.14.6±10.4, 225±9.5, 104.25±8.33, 81.37±8.8 and 199.3±10.7 ml/g of DM for whole pomace, seeds and peels as ground and unground respectively) were similar to the in situ findings (67.33±0.27, 79.6±0.8, 62.8±0.4, 36.07±1.53, 31.73±1.06 and 46.47±0.33% of DM for whole pomace, seeds and peels as ground and unground respectively). Correlations for DM degradability measured by two methods for whole tomato pomace and its components were 0.96, 0.98, 0.98, 0.98, 0.98, and 0.97 for whole pomace, seeds and peels as ground and unground respectively. According to the regression models, in vitro gas production for the DM contents of whole tomato pomace and its components could be used instead of the in situ technique at lower cost in shorter time.

Keywords