Comparison of Techniques to Determine the Ruminal and Post-Ruminal Protein Disappearance of Various Oilseed Meals

Abstract

Abstract: Rumind, p o s t - m k l and total tract cmde protein disappearance of cottomeed meal containing 105<br><br>(CSMH) or 65 (CSML) g oil per kg of dry matter (DM), soybean meal (SBM), rapeseed meal (RSM) and<br><br>sunflower meal (SFM), originating from Iranian plant varieties, were measured using in situ mobile bag, threestep<br><br>in situlin vitro (?-step) and in vitro enzymatic procedures. For the in situ mobile bag techmque, 4 Holstein<br><br>steers (450150 kg, body weight) fitted with m i n a l fistulae and T-shaped intestinal cannulae were used. Threestep<br><br>procedure was followed by m e n incubation of samples for 12 h and enzymatic incubation of m i n a l<br><br>undegradable samples. In vitro enzymatic technique was followed by 1 h borate- phosphate buffer incubation,<br><br>then 4 h in protease solution as m i n a l disappearance and enzymatic (pepsin and pancreatin) incubation of<br><br>ruminal undegradable samples. A significant (p&lt;0.01) effect was found between the procedures to measure<br><br>minal, post-mind and total tract CP dsappearance. The protein dsappearance of oilseed meals in the m e n<br><br>and post-men determined in vitro enzymatic procedure tended to be higher than ?-step technique. Postruminal<br><br>protein disappearance measured with in vitro procedure was higher (p&lt;0.01) than in situ mobile bag<br><br>and ?-step techmques (In vitro = 0.75, In situ mobile bag = 0.74 and ?-step = 0.60; SEM = 0.023, respectively).<br><br>There was a significant (p&lt;0.01) effect of feeds onminal, post-minal and total tract CP dsappearance. The<br><br>CSMH had a lower (p&lt;0.01) m i n a l CP disappearance, while the SFM had higher value (0.58 and 0.91,<br><br>respectively). The CSMH had lower m i n a l CP dsappearance compared with CSML (0.58 vs. 0.68,<br><br>respectively). The CSMLhad a lower @&lt;0.01) post-minal CP disappearance, while the SBM had higher value<br><br>(0.59 and 0.81, respectively). In addtion, our results indcated that when used to assess post-minal<br><br>disappearance of oilseed meal protein, the ?-step method can underestimate the dsappearance of protein.