In situ Evaluation of Ruminal Degradability and Intestinal Digestibility of Sunflower Meal Compared to Soybean Meal

The aim of this study was to compare the nutritional value of sunflower meal (SFM) and soybean meal (SBM) protein by determining both its ruminal degradability and intestinal digestibility. Three non lactating Jersey cows fitted with a rumen and T-type duodenal cannulas were used to estimate rumen degradability and intestinal digestibility of SFM and SBM dry matter (DM) and crude protein (CP). Samples of SFM were collected from seven sunflower processing plants (SFM1 to SFM7). Six different samples of SBM were collected from three main suppliers (SBM1 to SBM6). Both protein feeds were incubated in the rumen of the cows for 0, 2, 4, 8, 16, 24 and 48 h in 6 replications. The rapidly degradable fraction of DM averaged 24.8% for SFM which was lower (P<0.01) than that observed for SBM (29.2%). The effective DM degradability of SFM (56.2 %/h), at mean rumen outflow rate of 0.06/h, was lower (P<0.01) compared with SBM samples (67.3 %/h). The washable fraction a of CP was higher (P<0.01) for SFM samples (26.3%) in comparison to all batches of SBM (16.5%). The effective degradability of SFM CP (67.7 %/h) at rumen passage rate of 0.06/h was higher (P<0.01) than in SBM (63.0 %/h). The DM intestinal digestibility of SFM samples (42.6%) measured by the mobile bag technique was lower (P<0.01) compared to SBM samples (71.9%). The intestinal digestibility of SFM CP (89.9%) was also lower (P<0.01) than in SBM (94.6%). Results of this study indicate that SBM samples were more resistant to ruminal degradation than SFM. The data suggest that changing the toasting parameters can decrease degradability of SFM to improve protein quality.