Ruminal degradation of aerial biomass and seeds of wild species of Lupinus
Lagunes-Espinoza,Luz del C
Ruminal degradation of dry matter (DMD) and crude protein (CPD) for aerial biomass at the flowering stage and for the seeds of L. campestris, L. exaltatus, L. hintonii and L. montanus was determined using the nylon bag technique with two fistulated steers in five incubation times (3, 9, 12, 24 and 48 h), including a sample of soybean paste (SP). The data obtained were analyzed using PROC MIXED of SAS for repeated measures. The results showed interactions between species and incubation time for DMD and CPD. Among species of lupine, a high DMD and CPD of seeds were observed after three hours of incubation. At 48 h, DMD and CPD did not show significant variation between species: DMD ranged from 94.3% to 96.7% and CPD from 98.9 to 99.2%. The degradation rate of the insoluble fraction of the DM (kd) in lupine seeds ranged from 6.3 to 8.1% h-1, while that of the soluble fraction (SF) ranged from 42.3 to 57.3%, lower value that observed in SP. The DMD and CPD of aerial biomass showed statistically significant differences between species at 48 h of incubation. L. hintonii showed the lowest DMD (69.6%) and CPD (88.9%). L. montanus and L. campestris showed a lower SF and kd (kd of 5.4% h-1 in both, and 35.4 and 37.2 for SF, respectively) and high CPD of aerial biomass. It is concluded that the DM and CP of seeds and biomass of wild lupine were highly degradable as of 3 h of incubation. At 48 h, there were statistically significant differences between DMD and CPD of aboveground biomass (AGB). L. campestris and L. exaltatus showed the highest DMD and CPD of AGB and similar DMD and CPD of seeds.