Comparison of conventional and low-inhibitor soybeans with different heat treatments and lysine concentrations in diets for finishing pigs

Two experiments were conducted to determine the effects of gene expression for the Kunitz trypsin inhibitor, heat treatment, and concentration of lysine in the diet on nutritional value of soybeans for finishing pigs. In Experiment 1, 108 pigs (113 lb avg initial wt) were fed diets with two soybean cultivars (Williams 82 and Amsoy 71), with (+K) and without (-K) gene expression for the Kunitz trypsin inhibitor, subjected to three heat treatments (1/2-, 3/4-, and full-roasting). Nutritional value of the Williams 82 and Amsoy 71 cultivars was not different, but -K soybeans were superior to +K soybeans at all levels of heat treatment. Results indicated that full-roasted -K soybeans were of the greatest nutritional value, and 3/4-roasted -K soybeans were of equal nutritional value to full-roasted +K soybeans. In Experiment 2, Amsoy 71 soybeans (+K and -K) were fed raw and extruded, at 80 and 110% of the lysine concentration recommended by the NRC. Growth performance was improved by feeding the -K vs +K, extruded vs raw, and 110 vs 80% treatments. Additionally, the -K soybeans supported greater performance than +K soybeans, even when both were fully processed and fed in diets above the lysine requirement for finishing pigs

Effect of heat treatment on the nutritional value of low-inhibitor soybeans for nursery growing, and finishing pigs

Two hundred forty nursery pigs (12.8 lb initial wt) were used in a 28-d growth assay to determine the nutritional value of Williams 82 soybeans with (+K) and without (-K) gene expression for the Kunitz trypsin inhibitor. Treatments were soybean type (+K and -K) and heat treatment (none, half-roasting, and full-roasting time), in a factorial arrangement. The soybeans were heated in a Roast-a-Tron roaster, ground, and added to corn-dried whey diets formulated to be limiting in lysine (.88%). Pigs fed diets with -K soybeans gained 21% faster and were 13% more efficient than pigs fed diets with + K soybeans. As heat treatment was increased to full-roasting, rate and efficiency of gain increased. The + K soybeans were of lower nutritional value than the - K soybeans when fed raw or half-roasted, but the two soybean types were of similar nutritional value when fully roasted. Two additional experiments (66 individually fed pigs each) were conducted using growing and finishing pigs. The soybeans were added to corn-based diets formulated to contain .60 and .48% lysine for the growing and finishing phases, respectively. Growing pigs fed diets with the - K soybeans gained 10% faster, were 10% more efficient, and had 13% lower fat depth at the last rib than pigs fed the + K soybeans. Finishing pigs fed diets with the - K soybeans were more efficient and had lower fat depths than pigs fed the +K soybeans. Considering all three growth phases, the low-inhibitor (-K) soybeans were of greater nutritional value than the conventional (+ K) soybeans, with the greatest difference observed when the soybeans were fed raw. The nutritional value of both soybean types (+K and - K) was optimized with full-roasting. The half-roasting treatment was not sufficient to optimize the nutritional value of the low-inhibitor soybeans

Processing method affects the nutritional value of low-inhibitor soybeans for nursery pigs

One hundred weanling pigs (16.5 lb avg initial wt) were used in a 35-d growth assay to determine the effects of processing method (roasting in a Roast-A-Tron roaster vs extrusion in an Insta-Pro extruder) on the nutritional value of Williams 82 soybeans with (+K) and without (-K) gene expression for the Kunitz trypsin inhibitor. Treatments were: 1) soybean meal with added soybean oil, 2) + K roasted, 3) + K extruded, 4) -K roasted, and 5) -K extruded. All diets were corn-based and formulated to contain .92% lysine and 3.50 Mcal/kg DE for d 0 to 14 of the experiment and .76% lysine and 3.49 Mcal/kg DE for d 14 to 35 of the experiment. From d 0 to 14, pigs fed extruded soybeans (+K and -K) ate more feed (greater ADFI), grew faster (greater ADG), and were more efficient (better F/G) than pigs fed roasted soybeans. From d 14 to 35 and overall, the same effects were noted, i.e., pigs fed extruded soybeans had greater ADFI and ADG and better F G than pigs fed roasted soybeans. Also, pigs fed -K soybeans were more efficient than pigs fed +K soybeans. The average performance of all pigs fed diets containing the roasted and extruded soybeans was not different from that of pigs fed diets with soybean meal and added soybean oil, although diets with -K extruded soybeans consistently supported numerically greater rates and efficiencies of gain. Extrusion processing yielded soybean products of greater nutritional value than roasting, and -K soybeans were of greater nutritional value than +K soybeans when roasted or extruded

Extrusion processing of low-inhibitor soybeans improves growth performance of nursery pigs fed protein-adequate diets

One hundred fifty weanling pigs (15.4 lb avg initial wt) were used in a 35-d growth assay to determine the effects of processing method (roasting in a Roast-A-Tron roaster vs extrusion in an Insta-Pro extruder) on nutritional value of soybeans with (+K) and without (-K) gene expression for the Kunitz trypsin inhibitor. Treatments were: 1) soybean meal with added soybean oil; 2) +K roasted; 3) +K extruded; 4) -K roasted; and 5) -K extruded. All diets were corn-based and formulated to 1.25% lysine for d 0 to 14 and 1.10% lysine for d 14 to 35 of the experiment. For d 0 to 14, 14 to 35, and 0 to 35, pigs fed extruded soybeans had improved ADG and F/G compared to pigs fed roasted soybeans. Digestibilities of DM, N, and gross energy were greater for diets with extruded soybeans than diets with roasted soybeans, and diets with soybean meal and soybean oil were intermediate. The response to extrusion processing was greater with -K than +K soybeans, with pigs fed extruded -K soybean having the greatest growth performance and nutrient digestibilities and lowest skinfold thickness of any treatment. Extrusion processing of +K and -K soybeans improved growth performance and nutrient digestibility in weanling pigs fed protein-adequate diets

EC89-219 1989 Nebraska Swine Report

This 1989 Nebraska Swine Report was prepared by the staff in Animal Science and cooperating departments for use in the Extension and Teaching programs at the University of Nebraska-Lincoln. Authors from the following areas contributed to this publication: Swine Nutrition, swine diseases, pathology, economics, engineering, swine breeding, meats, agronomy, and diagnostic laboratory. It covers the following areas: breeding, disease control, feeding, nutrition, economics, housing and meats