Rumen fermentation and microbial yield of high- or low-protein diets containing ground soybean seeds or homemade rapeseed expellers evaluated with RUSITEC

Guadagnin, M., Tagliapietra, F., Cattani, M., Schiavon, S., Worgan, H. J., Belanche, A., Newbold, C. J. and Bailoni, L. 2013. Rumen fermentation and microbial yield of high- or low-protein diets containing ground soybean seeds or homemade rapeseed expellers evaluated with RUSITEC. Can. J. Anim. Sci. 93: 363–371. This experiment aimed to compare diets containing two crude protein (CP) concentrations [147 or 109 g kg −1 in dry matter (DM)] and two protein sources containing ground soybean seed (GSS) or rapeseed expeller (RSE). Diets were compared in terms of digestibility, volatile fatty acids (VFA) and ammonia concentrations, and N flows, using rumen simulation fermenters (RUSITEC). Home−made RSE (CP=287 g kg −1 dry matter and ether extract=199 g kg −1 DM) was produced using equipment adopted by small farms. Reduction of dietary CP content did not affect digestibility, except for a reduction of N apparent digestibility (P