Effects of roasting of lupins (Lupinus albus) and ...
|Title||Effects of roasting of lupins (Lupinus albus) and high protein variety of soybeans (AC Proteus) on chemical composition and in situ dry matter and nitrogen disappearance in dairy cows|
|Author(s)||M. S. Zaman, Mary A. McNiven, B. Grimmelt, J. A. MacLeod|
|Journal||Animal Feed Science and Technology|
|Abstract||Sweet white lupins (Lupinus albus) and a high protein variety of soyabeans, AC Proteus (HPSB), were roasted in an electric roaster at 300 degrees C for 1, 2, 3 or 4 min. Raw and roasted samples were analysed for total nitrogen, acid detergent insoluble N and protease insoluble N, and available rumen by-pass protein (RBP) was determined. In situ degradability of DM and N was determined using Dacron bags in the rumen of 3 ruminally cannulated dry cows. Soyabean meal was used as a control treatment. Roasting did not affect the total N content of lupins (4.9%) and HPSB (7.3%), but increased linearly (P<0.02) the protease insoluble N content of both. As roasting time increased the acid detergent insoluble N content of lupins (4.7, 5.1, 6.7 and 7.9% at 1, 2, 3 and 4 min roasting, respectively) and HPSB (4.9, 6.3, 6.6 and 7.2% at 1, 2, 3 and 4 min roasting, respectively) increased. Available RBP in roasted HPSB increased as roasting time increased (27.6, 33.8, 41.2 and 43.3% at 1, 2, 3 and 4 min roasting, respectively); however, roasting time did not affect RBP of roasted lupins (20.6%). Soyabean meal had a lower RBP percentage than roasted lupins or HPSB. Roasting reduced (P<0.01) effective degradation of DM and N in roasted lupins and HPSB at a calculated outflow rate in the rumen of 0.06 h/day. The effective degradation of N in HPSB or lupins at 4 min roasting was 10% lower than in soyabean meal..|
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