Determination of nutritive and digestibility values of tomato pomace before and after oil extraction in vitro and evaluation of ruminal disappearance of in situ

In this study, nutritional and digestibility value of tomato pomace before (TP) and after oil extraction (DTP) were measured. Lycopene content of TP and its rumen disappearance rate was determined. In a completely randomized design, gas production content of TP and DTP was measured in vitro. Ruminal disappearance of dry matter and lycopene of TP were determined at 0, 2, 6, 12, 24, 36, 48, 72 and 96 hours of incubation using fistula cows. Ruminal degradability parameters including rapidly degraded fraction (a), slowly degraded fraction (b), fractional rate of degradation (c), potential of degradability (PD) and effective degradability (ED) were estimated. Results showed that lycopene content of TP was 168 mg/kg DM. DTP contained higher crude protein, NDF, and ADF than TP. De-oiled TP showed higher gas production, digestibility of organic matter and short-chain fatty acids and lower N-ammonia as compared to TP. The values for a, b, c, PD and ED for dry matter were 57.1, 0.07, 66.4 and 49.3% and for lycopene were 3.87, 42.1, 0.076, 45.9 and 34.1, respectively. In conclusion, ruminal degradability of lycopene was about 30% meaning that about than 70% of lycopene by-passes the rumen. Moreover, de-oiled tomato pomace has reasonable nutritive values to be used in ruminant nutrition.