Extrusion of lupines with or without addition of reducing sugars: Effects on the formation of Maillard reaction compounds, partition of nitrogen and Nε-carboxymethyl-lysine, and performance of dairy cows

The extrusion of leguminous seeds induces the formation Maillard reaction compounds (MRC) as a product protein advanced glycation and oxidation, which lowers degradability in rumen. However, quantitative relationship between parameters pretreatment (i.e., addition reducing sugars) extrusion, MRC has not been established yet. Moreover, fate main stable MRC, Nε-carboxymethyl-lysine (CML), excretory routes never investigated ruminants. We aimed to test effects temperature white lupines with or without sugars on crude (CP) rumen, N use efficiency for milk production (milk N/N intake), performance dairy cows. Two experiments replicated 4 × Latin square design were conducted simultaneously 16 (3 rumen-cannulated) multiparous Holstein cows measure indicators ruminal CP (ruminal NH3 concentration, branched-chain volatile fatty acids), metabolizable supply (plasma essential AA concentration), (N isotopic discrimination), performance. In parallel, apparent total-tract digestibility dry matter, organic neutral detergent fibers, N, total Lys CML, partition CML measured both experiments. diets consisted DM basis 20% raw extruded 80% basal mixed ration corn silage, silage hay from permanent grasslands, pelleted concentrate, vitaminized mineral mix. Expected output temperatures lupine 115°C, 135°C, 150°C, before extrusion. numerically reduced vitro lupines, consequently increased predicted small intestine. Nitrogen balance urinary excretion did differ among dietary treatments either experiment. Milk yield at 150°C compared lupines. discrimination animal proteins (the difference δ15N plasma diet) lower sugars. Regardless sugar addition, true was affected, but urea concentration fat:protein ratio than study, we observed that average 26% apparently digested excreted urine, much proportion (0.63% average) secreted milk, no differences treatments. conclusion, showed enzymatic degradability, limited partition, highest