Influence of different levels of dried citrus pulp on in vitro ruminal fermentation kinetics of total mixed ration in goat rumen inocula

Abstract

Inclusion of dried citrus pulp (DCP) at different levels: 0 (control), 10% (DCP10), 20 (DCP20), and 30% (DCP30) of the total mixed ration (TMR) was evaluated by in vitro gas production (GP), and ruminal fermentation patterns, in a completely randomized design. Rumen fluid was collected before the morning meal from 8 gestating goats (Boer×Saanen, body weight 3±2.3 kg). GP was recorded at 2, 4, 6, 8, 10, 12, 24, 48, 72, and 96 h of incubation. Ruminal fermentation parameters such as 96 h partitioning factor (PF96), in vitro organic matter digestibility (IVOMD), metabolizable energy (ME), short-chain fatty acids (SCFA), and metabolizable energy (ME) were also estimated. Inclusion of DCP linearly increased (P<0.01) cumulative gas production at 24, 48, and 96 h after inoculation, as well as asymptotic gas production (b). Rations at 30% and 10% DCP had the highest values of gas production, whereas control and 20% DCP presented the same values (quadratic effect P<0.01). Lag phase (L) decreased linearly (P<0.001) with DCP addition. IVDMD and IVOMD increased linearly (P<0.01) with the inclusion of DCP in rations. The ration at 30% DCP (DCP30) had the greatest value of ME and SCFA, but no differences were observed in the PF96 among treatments. The data suggest that the DCP30 ration had the best impact on rumen gas production and IVDMD, IVOMD, ME, and SCFA.