LAUSR

BACKGROUND The objective of this study was to evaluate the effect of the proportion of pea (0%, 10%, 20% and 30%), as a partial replacement of soybean meal (SBM), in the fattening concentrate on ruminal fermentation in lambs. Gas and methane (CH4 ) production, in vitro dry matter degradability (IVDMD), ammonia (NH3 -N) and volatile fatty acid (VFA) production after 24 h of incubation were evaluated. Also, the concentrates were incubated in the rumen of the wethers for 2, 4, 6, 8, 12 and 24 h to evaluate the effects of pea inclusion on in situ dry matter degradability (DMD), organic matter degradability (OMD), nitrogen degradability (ND), NH3 -N and VFA production. RESULTS In the in vitro assay, the inclusion of pea only affected gas production (mL d-1 degraded dry matter), CH4 production (mL d-1 degraded dry matter) and IVDMD (P<0.05) and tended to affect NH3 -N content (P<0.10) without affecting VFA production. In the in situ assay, the inclusion of pea increased DMD, OMD and ND linearly (P<0.001), whereas pea inclusion decreased NH3 -N content linearly (P<0.05). Neither total VFA production nor the proportion of acetic acid were affected by pea inclusion (P>0.05), but the proportion of propionic proportion increased with the proportion of pea included. CONCLUSIONS The best level of pea inclusion in the concentrate could not be established based on the results of this study. However, the results showed that the inclusion of pea provides a good alternative protein source. This article is protected by copyright. All rights reserved.