Fermented soybean meal as a vegetable protein source for nursery pigs: I. Effects on growth performance of nursery pigs.

Four experiments were conducted using 671 nursery pigs to evaluate fermented soybean meal (FSBM) as a new vegetable protein source for nursery pigs. In Exp. 1, a total of 192 pigs weaned at 19.2 +/- 0.3 d of age were fed 3 diets (8 pens per treatment) for 2 wk: a control diet (without FSBM) and 2 diets with 3 and 6% FSBM replacing soybean meal, followed by a common diet for the next 2 wk. In Exp. 2, a total of 160 pigs weaned at 21.6 +/- 0.2 d of age were fed 4 diets (5 pens per treatment) for 2 wk: a control diet (without FSBM but with 25% dried skim milk; DSM) and 3 diets with 3, 6, and 9% FSBM replacing DSM based on CP. Concentrations of CP, Lys, Met, Thr, and Trp were kept consistent among diets in Exp. 1 and 2. In Exp. 3, a total of 144 pigs weaned at 22.1 +/- 0.2 d of age were fed 3 diets (6 pens per treatment) for 2 wk: a control diet (without FSBM but with 40% DSM) and 2 diets with 5 and 10% FSBM replacing DSM based on CP. Concentrations of CP, Lys, Met, Thr, Trp, and lactose were kept consistent among diets. In Exp. 4, a total of 175 pigs weaned at 20.7 +/- 0.4 d of age were fed 5 diets (5 pens per treatment) for 3 wk: a basal diet [15.5% CP without plasma protein (PP) and FSBM], 2 diets (18.4% CP) with 3.7% PP or 4.9% FSBM, and 2 diets (21.2% CP) with 7.3% PP or 9.8% FSBM. Concentrations of Lys, Met, Thr, and Trp were kept consistent among diets with the same CP concentrations. Pigs had access to feed and water ad libitum and their BW and feed intake were measured weekly for all experiments. Use of up to 6% FSBM replacing soybean meal improved (P < 0.05) G:F and diarrhea scores of nursery pigs (Exp. 1). Use of up to 9% FSBM replacing DSM reduced (P < 0.05) ADG and G:F (Exp. 2). When lactose concentrations were equal, FSBM could replace up to 10% DSM without adverse effects on ADG and G:F (Exp. 3). Relative bioavailability of protein in FSBM to PP was 99.1% (Exp. 4). Collectively, FSBM can serve as an alternative protein source for nursery pigs at 3 to 7 wk of age, possibly replacing the use of DSM and PP but excluding the first week postweaning for PP when balancing for AA and lactose.