Effect of processing methods (Rolling, steam-flaking, pelleting) on protein molecular structure profile, rumen degradation, and intestinal digestion of cool-climate adapted oats grain in comparison with barley grain in western Canada

Processing cereal grains can lead to an improvement in nutrient digestibility and have an impact on the rate and site of grain nutrients digestion. There are several methods of processing and it is important to understand which processing method is better recommended for dairy cows ration with cool-climate adapted oat grain. The main objective of this study was to determine the impact of processing methods (Rolling, Steam-Flaking, Pelleting) on the nutritional and digestive characteristics and the protein related molecular spectral profiles of cool-climate adapted oats grain in comparison to barley grain. Results showed that heat treating oats (steam-flaking and pelleting) did not alter SCP of cool-climate adapted oats grain. Steam-flaking increased the intermediate degradable protein fraction PB1 (+13.68% CP), while reduced PA2 (-17.19% CP) fraction when compared to rolled oats. Steam-flaking also increased bypass CP (+14.71%BCP) while decreasing the EDCP in the rumen (- 14.71%). In the DVE/OEB system, steam-flaked oats and pelleted oats presented lower values of OEB when compared to rolled oats, but they were higher than the value for rolled barley. Univariate analysis of the protein molecular structure features showed only changes in the protein beta-sheet height, with flaked oats presenting the higher value, pelleted oats showing the lowest value and rolled barley and oats showing intermediate values. There was overlap among the treatments when analyzed with PCA, implying similar molecular structure among the treatments.