Evaluation of the inclusion of soybean oil and soybean processing by-products to soybean meal on nutrient composition and digestibility in swine and poultry

This experiment was designed to evaluate the effects of selected soybean (SB) processing byproducts (gums, oil, soapstock, weeds/trash) when added back to soybean meal (SBM) during processing on the resulting nutrient composition, protein quality, nutrient digestibility by swine, and true metabolizable energy (TMEn) content and standardized AA digestibility by poultry. To measure ileal DM and nutrient digestibility, pigs were surgically fitted with a T-cannula in the distal ileum. The concentration of TMEn and the standardized AA digestibility by poultry were determined using the precision fed cecectomized rooster assay. Treatments in the swine experiment included SBM with no by-products; SBM with 1% gum; SBM with 3% gum; SBM with 0.5% soapstock; SBM with 1.5% soapstock; SBM with 2% weeds/trash; SBM with a combination of 3% gum, 1.5% soapstock, and 2% weeds/trash; SBM with 5.4% soybean oil; and roasted SB. A 10 x 10 Latin square design was utilized. The experiment was conducted at the University of Illinois, Urbana-Champaign, and at The Ohio State University, Columbus. In the swine experiment, apparent ileal DM, OM, CP, and AA digestibilities were reduced (P < 0.05) when pigs consumed the combination by-product diet compared with the diet containing no by-products. Apparent ileal digestibilities of DM, CP, and total essential, total nonessential, and total AA were lower (P < 0.05) for any diet containing by-products compared with the diet with no by-products. Apparent ileal digestibilities of DM, OM, CP, and AA were lower (P < 0.05) for the roasted SB-compared with the SB oil-containing diet. In the rooster experiment, TMEn values were greater (P < 0.05) for roasted SB compared with SBM with no by-products and increased linearly as the addition of soapstock increased. Individual, total essential, total nonessential, and total AA digestibilities were lower (P < 0.05) for roosters fed roasted SB versus SBM devoid of by-products. Gums, soapstock, and weeds/trash reduce the nutritive value of the resultant meal when they are added back during processing.     

Digestion of soybean meal and canola meal protein and amino acids in the digestive tract of young ruminants

Eight male Holstein calves (body weight 68 +/- 5 kg; age 75 +/- 6 d), each with a permanent re-entrant pancreatic cannula and T-type ileal and duodenal cannulas, were used in a crossover design with four animals per group to determine amino acid kinetics and digestibilities in the digestive tract of calves fed soybean meal (SBM) and canola meal (CM) protein. The SBM and CM diets were fed twice daily at a level of 900 g at each feeding time (air-dry basis). With the exception of methionine, crude protein and amino acid flows at the proximal duodenum, expressed as a percentage of intake, were not influenced by dietary protein source. Apparent ileal and total tract digestibilities of CP and amino acids were reduced (P less than .05) by feeding CM compared to SBM, but apparent ileal digestibility of methionine was not affected by dietary protein source. Except for methionine, net disappearance of all amino acids in the small intestine, relative to the amount fed, was higher for the SBM diet than for the CM diet. Net disappearance or synthesis of amino acids in the large intestine were not affected by dietary protein source. Similarly, dietary protein source did not affect (P greater than .05) the secretion of pancreatic juice or concentrations of protein, chymotrypsin and trypsin in pancreatic juice. Soybean meal protein has higher ileal and total gastrointestinal tract digestibility than CM protein for young, growing calves.     

Effects of soybean meal particle size on growth performance of nursery pigs

We used 360 nursery pigs (35 +/- 3 d of age) in two 21-d growth assays to determine the effects of soybean meal particle size on growth performance. In both trials, there were six pigs per pen and 10 pens per treatment. Pigs were weaned on d 21 and fed the same phase I diet for 7 d after weaning, followed by a phase II diet from d 7 to 14. On d 14, all pigs were weighed and randomly allotted to one of three dietary treatments. Experimental diets contained 61.9% corn, 34.4% soybean meal, and 3.7% vitamins and minerals. In Exp. 1, 90 barrows and 90 gilts (9.2 +/- 2.3 kg BW) were fed diets containing extruded-expelled soybean meal ground to 965, 742, or 639 microm, which resulted in whole-diet particle sizes of 728, 719, and 697 microm, respectively. Reducing extruded-expelled soybean meal particle size from 965 or 742 to 639 microm in the diet did not affect (P > 0.10) ADG (541, 538, and 542 g/d), ADFI (886, 875, and 855 g/d; as-fed basis), or gain:feed ratio (0.61, 0.61, 0.64), respectively. In Exp. 2, 90 barrows and 90 gilts (9.9 +/- 2.6 kg BW) were fed diets containing solvent-extracted soybean meal ground to 1,226, 797, or 444 microm, which resulted in whole-diet particle sizes of 732, 681, and 629 microns, respectively. Like Exp. 1, reducing particle size of solvent-extracted soybean meal did not affect (P > 0.10) ADG (482, 487, and 484 g/d), ADFI (738, 742, and 736 g/d; as-fed), or gain:feed (0.65, 0.65, and 0.65). Reducing particle size of extruded-expelled soybean meal or solvent-extracted soybean meal increased the angle of repose (maximum degree at which a pile of material retains its slope), indicating that as particle size decreased, flowability characteristics decreased. However, the angle of repose of the complete diets was greater than that for the soybean meals, which indicates that decreasing the particle size of soybean meal had minimal effects on flow characteristics of the complete diet. Previous research has shown that decreasing grain particle size improves digestibility and feed efficiency, and decreased soybean meal particle size has resulted in improved amino acid digestibility. However, the results of our experiments suggest decreasing particle size of either extruded-expelled soybean meal or solvent-extracted soybean meal does not affect nursery pig growth performance.     

Amino acid digestibility in dry extruded-expelled soybean meal fed to pigs and poultry

The digestibility of AA in dry extruded-expelled soybean meal (DESBM) and regular, solvent-extracted soybean meal (SBM) were determined in pigs and poultry. In the pig assay, 4 Cotswold barrows (average initial BW of 80.4 kg) fitted with a T-cannula at the distal ileum were allotted to 4 semipurified diets in a 4 x 4 Latin square design. Diet 1, a low protein diet (5% casein), was used to quantify endogenous CP and AA losses. Diets 2, 3, and 4 were formulated to contain 35% regular, solvent-extracted SBM; batch 1 of DESBM (DESBM-1); and batch 2 of DESBM (DESBM-2), respectively, as the sole source of protein. The DESBM samples were obtained from 2 different batches but were subjected to the same processing conditions. Chromic oxide (0.3%) was included as a digestibility marker in all diets. Compared with DESBM-1 and DESBM-2, apparent ileal digestibility of DM in SBM was greater (P < 0.05). Apparent and true ileal digestibilities of AA in SBM were greater (P < 0.05) compared with DESBM-2. In the poultry assay, 4 dietary treatments were each assigned to adult cecectomized roosters in a completely randomized design. Treatment 1 was a nonnitrogenous diet (NND; 90% sucrose and 10% vegetable oil) used to estimate endogenous N and AA losses. Treatments 2, 3, and 4 contained SBM, DESBM-1, and DESBM-2 as the only source of protein. Each of these diets was fed in 25-g quantities formulated to provide 5 g of CP from the respective soybean meal source. The SBM had greater (P < or = 0.05) true digestibility for isoleucine, leucine, cysteine, proline, serine, and tyrosine compared with DESBM-1. The results indicate that, relative to regular, solvent-extracted soybean meal, AA digestibilities of different batches of dry extruded-expelled soybean meal varied in pigs and poultry.     

Nitrogen balance and amino acid disappearance from the small intestine in calves fed soybean meal-, toasted soybean meal- or corn gluten meal-supplemented diets

Nine crossbred (Hereford X Angus X Charolais) heifer calves (139 kg; 6 mo of age) with abomasal and ileal cannulas were used in a repeated design to evaluate N balance and amino acid disappearance in the small intestine. Calves were fed either soybean meal (SBM), toasted SBM (TSBM, 93 C for 90 min) or corn gluten meal (CGM) as supplemental protein sources. Each calf received approximately 83 g N/d from a cottonseed hull-corn based diet with 43% of the total dietary N supplied by the test proteins. Each experimental period consisted of a 10-d adaptation, 6-d digesta collection and 5-d excreta collection. Following the first 21-d period, calves were randomly re-allotted to treatment and the sampling process was repeated. Dry matter (64%) and N digestibilities (61%) and N retention (36.8 g/d) were similar (P greater than .10) among treatments. Nitrogen flow to the small intestine was similar for TSBM- and CGM-fed calves (119.1 g/d), but greater (P less than .01) than for those offered SBM (96.3 g/d). Offering TSBM and CGM resulted in greater quantities of essential, nonessential and total amino acids reaching the abomasum compared with SBM. Total amino acid flow to the small intestine was 100, 120 and 128% of intake for SBM, TSBM and CGM, respectively. Numerically, amino acid digestibility was lower in CGM-fed calves. Methionine digestibility was highest (64.6%), while histidine was lowest (43.7%). Feeding CGM may result in greater quantities of amino acids reaching the small intestine; however, several of these amino acids may be less digestible than for TSBM.     

不同粉碎粒度的豆粕对断奶仔猪生长性能和养分消化率的影响

本试验研究不同粉碎粒度的豆粕对断奶仔猪生长性能和养分消化率的影响,选用26～28日龄断奶(7.9±0.7)kg杜×长×大健康仔猪80头,按体重、性别相同原则随机分为4个处理,每处理设5个重复,每个重复4头猪。各个处理组采用相同的日粮组成,对照组饲喂含常规粉碎豆粕(目标粒径为750μm)的日粮,处理1、2、3分别饲喂含目标粒径为150、30、6μm豆粕的日粮。结果表明:使用粉碎粒度低于30μm豆粕的日粮提高了断奶仔猪日增重(P<0.05),明显提高采食量(P>0.05),降低饲料增重比(P<0.05),显著降低断奶仔猪的腹泻频率;使用粉碎粒度低于30μm豆粕的日粮提高断奶仔猪日粮氮、磷表观消化率(P<0.05),改善能量消化率(P=0.063)和有机物表观消化率(P=0.082),显著提高必需氨基酸的表观消化率(P<0.05)。粉碎粒度低于30μm的超微粉碎豆粕可显著提高断奶仔猪日粮蛋白质的消化效率,提高断奶仔猪的生长性能,改善了豆粕作为蛋白质营养源的生物适应性。     

热处理对大豆制品在生长猪回肠表观和真可消化氨基酸消化率的影响

试验比较了不同热处理时间大豆片、普通豆粕和去皮豆粕在生长猪回肠表观和真消化率的影响。试验采用12头回肠末端安装简单T型瘘管的生长猪,6×6有重复拉丁方设计。采用玉米淀粉-豆粕半纯合型日粮,配制酪蛋白日粮用以测定内源氮和氨基酸的损失量。结果表明:随着大豆片热处理时间的延长(0～18min),粗蛋白质和氨基酸的回肠表观和真消化率均显著提高(线性效应,P<0.01)。生大豆片的粗蛋白质和氨基酸的消化率显著低于普通豆粕和去皮豆粕(P<0.01),但普通豆粕与去皮豆粕间差异不显著(P>0.05)。     

The significance of small vs large intestinal digestion of cereal grain and oilseed protein in the equine

Mature ponies fitted with permanent ileal cannulas were used in two 3×3 Latin square experiments to quantify prececal, postileal and total tract digestion of N. In trial 1, corn, oats and sorghum were each fed with coastal Bermuda grass hay in 75:25 ratios. Apparent prececal digestibilities were similar (P>.05) and averaged 46.6%. By-difference procedures were employed to calculate digestibility of the cereal grain N only and apparent prececal N digestibility averaged 57.1%. In trial 2, a basal corn and hay diet was supplemented with cottonseed meal and soybean meal. Apparent total tract N digestibilities were similar (P>.05) across treatments, and prececal digestibility averaged 45.6%. By-difference calculations were used to determine digestibility of SBM and CSM N alone. Apparent prececal digestibility of SBM was 52.5% and was lower (P<.05) than 81.2% for CSM. It is possible that inadequate or excessive heat treatment of SBM affected enzymatic digestion. True digestibility of total rations fed in trial 2 was estimated by linear regression of nitrogen digested on nitrogen intake or N presented to the large intestine. True N digestibility of diets containing SBM and CSM was 54.7% and 69.4%, respectively.     

Effects of Corn and Soybean Meal Particle Size on Phosphorus Use in Turkey Poults

Two 28-d experiments were conducted to evaluate the effect of grinding corn or soybean meal (SBM) to various particle sizes on P utilization in turkey poults. Dietary Ca was formulated to be 1.20% in the corn-SBM-based diets of both studies and nonphytate P (NPP) was calculated to be 0.40% in experiment 1 and 0.48% in experiment 2. In experiment 1, corn that had been processed through a roller mill was used or was ground through 3 different screen sizes in a hammer mill to yield 4 corn particle sizes ranging from about 600 to 1,100 μm. Initial (7 d) growth was reduced when the coarsest corn was fed due to lower feed intake. Phosphorus utilization was improved the first 2 wk as corn particle size increased as measured by incidence of rickets, tibia ash, and total P retention. Gizzard weight and phytate P retention were increased at 28 d as corn particle size increased. In experiment 2, corn was ground to approximately 850 μm and commercial SBM (856 μm) was used or ground to 2 finer particle sizes in a hammer mill. Gizzard weight and phytate P retention were increased at 28 d as SBM particle size increased. Other parameters were not affected at least partially due to the higher dietary NPP level fed to prevent severe rickets observed in the first trial. These studies show that young poults can utilize P better from coarser corn and soybean meal, especially when dietary P is low.     

Evaluation of low-oligosaccharide, low-phytate whole soybeans and soybean meal in canine foods

Eight mature dogs (19.3 +/- 0.1 kg) were used in an experiment to compare the effects of feeding soybeans containing low concentrations of oligosaccharides and phytate on nutrient availability in complete foods fed to dogs. All foods were formulated to be isonitrogenous and contained low-oligosaccharide, low-phytate soybean meal (LLM); conventional soybean meal (SBM); low-oligosaccharide, low-phytate whole soybeans (LLB); or conventional whole soybeans (WSB) as the protein source. Daily DMI averaged 287 +/- 4 g/d. Fecal outputs were greatest for LLB and WSB, averaging 48.2 g DM/d. Small intestinal DM digestibility ranged from 80.9% (LLM) to 74.0% (LLB) but was unaffected by treatment. Large intestinal DM digestibility did not differ among treatments (P = 0.652). Total-tract DM digestibility was higher (P = 0.020) for LLM (87.0%) than for SBM (84.8%). No difference in total-tract DM digestibility was observed for the two WSB foods (average = 83.3%; P = 0.286). Nitrogen retention did not differ among foods containing LLM and SBM (1.2 g of N/d; P = 0.486) or LLB and WSB (0.9 g of N/d; P = 0.225). Small intestinal N digestibility did not differ among LLM- and SBM-containing foods (80.6%; P = 0.190) or LLB and WSB (69.3%; P = 0.640). Total-tract N digestibility did not differ among foods containing LLM and SBM (83.5%; P = 0.627) or LLB and WSB (76.8%; P = 0.968). Tryptophan digestibility was higher for SBM than for LLM (P = 0.039). Histidine and tryptophan digestibilities were higher in WSB compared with LLB (P = 0.049 and P < 0.001, respectively). No differences in nonessential AA digestibility were observed when comparing soy-based foods. The results of this study demonstrate that LLM, SBM, LLB, and WSB can be effective sources of protein for canine foods and have a high digestibility. Differences in small intestinal digestibility of tryptophan and histidine may require consideration when formulating diets using low-oligosaccharide, low-phytate soybeans or meal.     

Effects of level of supplemental phytase on ileal digestibility of amino acids, calcium, and phosphorus in dehulled soybean meal for growing pigs.

Ileally cannulated pigs were used to assess the effects of four dietary levels of microbial phytase (Natuphos) on the apparent and true digestibility of Ca, P, CP, and AA in dehulled soybean meal. Fourteen pigs (25 kg initial BW) were surgically fitted with T-cannulas at the terminal ileum and assigned to diets in a replicated 7 x 7 Latin square design. Following a 14-d recovery, four diets consisting of 30.5% soybean meal with 0, 500, 1,000, or 1,500 units of phytase/kg of diet were fed. Diets 5 (1.05% lysine, 0.90% Ca, and 0.75% P) and 6 (1.05% lysine, 0.90% Ca, and 0.75% P) contained 35.25% soybean meal and 27.0% soy protein concentrate, respectively. Diet 7 (0.37% lysine, 0.03% Ca, and 0.05% P) was a low-CP, casein-based diet used to estimate the nonspecific endogenous losses of Ca, P, CP, and AA in order to estimate the true digestibility of these nutrients. All diets contained cornstarch and dextrose and were fortified with vitamins and minerals. Chromic oxide was used as an indigestible indicator. The diets were fed daily at 9% of metabolic BW (BW0.75). Apparent and true ileal digestibility of P increased quadratically (P < 0.01) and true digestibility of Ca increased linearly (P < 0.07) with increasing levels of phytase. Apparent digestibility of Ca was unaffected (P = 0.15) by phytase level. Apparent and true ileal digestibility of CP and most AA increased slightly with the addition of 500 units of phytase/kg of diet, but not at higher levels of phytase supplementation (in most cases, cubic effect, P < 0.05). Apparent and true ileal nutrient digestibility coefficients were unaffected by soybean meal source (Diet 1 vs Diet 5), except for arginine and Ca. The apparent and true digestibility coefficients for most of the AA tended (P < 0.10) to be lower in diets containing soy protein concentrate vs the common source of soybean meal used in Diet 5, but ileal digestibilities of Ca and P were unaffected (P = 0.15). In this study, supplemental microbial phytase did not improve the utilization of AA provided by soybean meal but was an effective means of improving Ca and P utilization by growing swine fed soybean meal-based diets.     

Effects of different heat treatments during processing on nutrient digestibility of soybean meal in growing swine

Four soybean meals (SBM) were prepared in a commercial solvent-extraction plant to give a much wider range in heat treatment than is usually found among commercially available SBM. The meals were designated in ascending order of heat treatment as Under, Normal, Over and Rumen Escape. The Normal meal was processed using standard operating conditions. The Under meal received less heat treatment by reducing the steam pressure and retention time in the desolventizer-toaster. Over and Rumen Escape meals received further heat treatment in an additional four-compartment toaster. The Over meal received less heat treatment than the Rumen Escape meal by reducing steam pressure and retention time in both toasters. Crude protein content was similar for the four meals, but lysine tended to decrease with increasing heat treatment. In general, urease activity, trypsin inhibitor, protein dispersibility index and nitrogen solubility index decreased with increasing heat treatment. The +a Hunterlab color values increased as heat treatment increased. Apparent ileal digestibility of N and amino acids were similar for all meals (P greater than .05); however lysine digestibility for the Rumen Escape meal was 3.3 percentage units lower than the average of the lesser-heated meals. Energy digestibilities and nitrogen balance data were also similar (P greater than .05) for the four meals, but the apparent biological value of the Rumen Escape meal was 4.5 percentage units lower than the average of the other meals. There were no differences in nutritional value among the Under, Normal and Over meals, which represent the range in heat treatment usually found among SBM. The Rumen Escape meal, which received more severe heat treatment, tended to have lower nutritional value than the lesser-heated meals.     

Amino acid profile of escaped feed protein after rumen incubation and their intestinal digestibility.

The crude protein content and amino acid profile of seven feedstuffs (linseed meal, maize gluten meal, rapeseed meal, rapeseed meal protected, soybean meal, fullfat soybean extruded and sunflower meal) were determined before and after ruminal incubation for 16 h in three bulls with large rumen cannulas. The intestinal disappearance of amino acids was measured using mobile bag technique. Ruminal incubation affected amino acid profile of all experimental feedstuffs. Crude protein degradation varied from 29.3% for maize gluten meal to 86.4% for rapeseed meal. A tendency towards increased disappearance was observed for glutamic acid, histidine, lysine and proline and decreased disappearance for branched-chain amino acids. The intestinal crude protein digestibility was higher than > 80%, except rapeseed meal (66.4%) and sunflower meal (77.8%). The least digestible individual amino acids were methionine and isoleucine in rapeseed meal, histidine and methionine in rapeseed meal protected and arginine in sunflower meal. In general, the lowest amino acid digestibilities were found in feedstuffs with the highest fibre content. The feedstuffs show that they have different potential for supplying of limiting amino acids. Of particular value are the feedstuffs with low crude protein degradability in the rumen and high intestinal digestibility of amino acids.     

Intestinal supply of amino acids in sheep fed alkaline hydrogen peroxide-treated wheat straw-based diets supplemented with soybean meal or combinations of corn gluten meal and blood meal

The intestinal supply of amino acids (AA) in sheep fed alkaline hydrogen peroxide-treated wheat straw (AHPWS)-based diets supplemented with soybean meal (SBM) or corn grain plus combinations of corn gluten meal (CGM) and blood meal (BM) was measured in a 5 X 5 latin square. Sheep (avg wt 45 kg) with ruminal, duodenal and ileal cannulas were fed diets containing 65% AHPWS supplemented with the following protein sources: soybean meal (SBM), corn gluten meal (CGM), blood meal (BM), 2/3 CGM:1/3 BM and 1/3 CGM:2/3 BM. Total nitrogen (N) flow at the duodenum was not affected (P greater than .05) by protein source. Flows of bacterial N and AA increased (P less than .05) and flows of nonbacterial N and AA decreased (P less than .05) when wethers were fed SBM vs corn plus other protein sources. When diets contained SBM, quantities of total AA at the duodenum were lower (P less than .05) and the profile of AA supplied to the intestine was altered substantially. Total flows of AA at the duodenum and total quantities of AA disappearing from the small intestine were similar (P greater than .05) for all diets containing BM and CGM, but flows and disappearance of valine, histidine, lysine and arginine increased linearly (P less than .05), whereas flows and disappearance of leucine, isoleucine and methionine decreased linearly (P less than .05) as BM replaced CGM in the diets. Results suggest that quantities of individual AA flowing to the duodenum and disappearing from the intestine of wethers fed AHPWS-based diets can be altered by source of dietary protein. Furthermore, feeding protein sources resistant to ruminal degradation in combination may improve the profile of AA supplied to the intestine.     

Nutritional evaluation of poultry by-product meal as a protein source for ruminants: small intestinal amino acid flow and disappearance in steers.

Six Angus steers (260+/-4 kg initial BW) fitted with ruminal, duodenal, and ileal cannulas were used in a 6 x 6 Latin square design to evaluate the effect of feeding poultry by-product meal (PBM) on small intestinal flow and disappearance of amino acids. The diets were provided at 2% of BW on a DM basis, formulated to contain 11.5% CP, and consisted of 49% corn silage, 36% cottonseed hulls, and 15% supplement on a DM basis. Supplements were formulated to contain 37% CP with sources of supplemental N being soybean meal (100% SBM) and 0, 25, 50, 75, and 100% PBM, with urea used to balance for N. Duodenal flow of all amino acids increased linearly (P < .07) as PBM increased in the diet and, except for His, increased (P < .09) for 100% PBM compared with 100% SBM. Similar results were observed for duodenal flow of nonbacterial amino acids, which linearly increased (P < .05) with PBM and were greater (P < .05) for 100% PBM than for 100% SBM. Soybean meal increased (P < .09) the duodenal flow of nonbacterial Lys compared with 0% PBM, and 0% PBM increased (P < .04) flow of Val, Ala, and Pro compared with 100% SBM. Duodenal bacterial essential, nonessential, and total amino acid flows were not affected (P > .80) by PBM; however, they were greater (P < .02) for 100% SBM than for 100% PBM. In addition, nonessential and total bacterial amino acid flows were increased (P < .06) for 100% SBM compared with 0% PBM. Small intestinal disappearance of Lys and Pro increased linearly (P < .09) as PBM increased, and 100% PBM increased (P < .07) disappearance of Arg and Ala compared with 100% SBM. Supplemental N source had no effect (P > .31) on apparent small intestinal disappearance of essential, nonessential, and total amino acids. These data suggest that when PBM, SBM, and urea were used as sources of supplemental N, the daily disappearance of amino acids from the small intestine of steer calves consuming a corn silage- and cottonseed hull-based diet was similar.     

Nitrogen utilization and ruminal fermentation in steers fed soybean meal treated with formaldehyde

Four rumen-fistulated steers averaging 400 kg in body weight were used in a 4 X 4 Latin square arrangement with 18-d periods to investigate the effect of treating soybean meal (SBM) with formaldehyde on nitrogen (N) utilization and ruminal fermentation. Experimental diets, on a dry matter basis, consisted of 42% corn silage, 48.5% cracked corn-mineral mixture and 9.5% SBM treated with 0, .3, .6 or .9% formaldehyde by weight. Dry matter and organic matter digestibilities were not affected by treatment. Formaldehyde treatment of SBM resulted in a linear decrease in N digestibility (P less than .005) and urinary N excretion (P less than .01) and a quadratic increase (P less than .05) in N retention. The depression in apparent N digestibility was small when SBM was treated with .3% formaldehyde. This level of formaldehyde treatment also had little effect on in vitro enzymatic hydrolysis of SBM. Ruminal ammonia-N concentrations were lower (P less than .05) in steers fed formaldehyde-treated SBM. Ruminal pH was lower (P less than .05) at 6 and 8 h postfeeding while volatile fatty acid concentrations were higher (P less than .05) at 8 and 12 h postfeeding for steers fed untreated SBM. Propionic acid (mol/100 mol) decreased linearly (P less than .05) with increasing level of formaldehyde treatment. Urea-N concentrations in plasma were decreased (P less than .001) and plasma-free essential amino acid concentrations were increased (P less than .10) by formaldehyde treatment. Ruminal disappearance of N from polyester bags containing the SBM supplements was greatly reduced (P less than .005) by formaldehyde treatment.(ABSTRACT TRUNCATED AT 250 WORDS)     

不同温度膨化全脂大豆对仔猪氮平衡和氨基酸消化率的影响

本试验目的在于检测不同温度下蒸汽膨化的全脂大豆对仔猪氮平衡和氨基酸消化率的影响。2个氮平衡试验共用24头杂交去势公猪,平均体重5.1公斤,21日龄断奶时,在小肠末端手术安装T—形瘘管。所用基础日粮含1.25％赖氨酸,10％豆油。10％葡萄糖和浸提豆粕,利用经110℃、130℃和150℃蒸汽膨化处理的三种全脂大豆,以等氮和等赖氨酸来替代基础日粮中的豆粕,用玉米淀粉补足日粮的百分比。代谢试验室内安有自动控温和通风设备。每个氮平衡试验收集粪尿和食糜样本2期。结果表明,仔猪采食含有在130℃下膨化的全脂大豆日粮后,氮消化率高于(p<0.05)在110℃下膨化的全脂大豆。而经150℃膨化处理的大豆,氮存留量,氮消化率,氮存留量没有进一步的改善,经130℃膨化的全脂大豆其赖氨酸、蛋氨酸和异亮氨酸的回肠表观消化率,高于(p<0.05)经110℃和150℃处理的大豆。但是,苏氨酸、缬氨酸和亮氨酸的回肠末端表观消化率随膨化温度的升高而增加。本试验表明,全脂大豆经130℃蒸汽膨化处理有利于改善仔猪对大豆中赖氨酸、蛋氨酸和异亮氨酸的回肠表观消化率,可以改善氮沉积量和氮存留率,但与优质豆粕相比,效率不显著。     

Effects of dietary energy level and protein source on site of digestion and duodenal nitrogen and amino acid flows in steers

Six steers (468 kg) with ruminal and duodenal cannulas were fed diets formulated for two levels of energy containing three crude protein (CP) sources in a 6 X 6 Latin square with a 2 X 3 factorial arrangement of treatments. Energy levels were 2.17 and 2.71 Mcal metabolizable energy (ME)/kg dry matter (DM) provided by hay-corn (H) and corn silage-corn (CS) diets, respectively. Soybean mean (SBM), corn gluten meal-urea (CGM) and urea (U) provided 33% of dietary CP in 12% CP diets. Apparent organic matter (OM) digested in the stomach was not affected (P greater than .05) by energy level or CP source, but OM truly digested in the stomach was greater (P less than .05) when steers were fed the CS compared with the H diet. Duodenal flow of non-NH3 N was greater (P less than .05) when steers were fed CS compared with H and when fed SBM or CGM compared with U. Efficiency of bacterial protein synthesis and duodenal bacterial N flow were increased (P less than .05) when steers were fed CS, but non-NH3, nonbacterial N flow to the duodenum was increased (P less than .05) when steers were fed H. When steers were fed CS rather than H, flows (g/d) of bacterial amino acids were greater (P less than .05), but flows of nonbacterial amino acids tended (P less than .08) to be less. Total amino acid flows were not affected (P greater than .05) by energy level. Duodenal flows of total amino acids tended (P less than .06) to be greater when steers were fed CGM compared with SBM or U, due mainly to an increased (P less than .05) flow of nonessential amino acids.     

Feeding value of frost-damaged soybeans for lambs.

Three experiments were conducted to determine the relative feeding value of frost-damaged soybeans (FDS) for ruminants. Frost-damaged soybean ether-extract content was variable and differed (P less than .05) from mature soybeans. Isonitrogenous supplementation of corn silage diets with soybean meal (SBM), SBM+soybean oil (SBO), mature raw soybeans (MSB), and FDS was compared in sheep. Acid detergent fiber and apparent N digestion were lower (P less than .001) for supplements containing oil. Nitrogen retention was reduced (P less than .07) only for raw soybean supplements. Ruminal NH3 N and branched-chain VFA concentrations differed (P less than .01) between SBM and supplements containing oil. Maximum tolerable inclusion level of FDS in corn silage diets was tested in wethers using diets containing 0, 7, 14, or 21% FDS. Dry matter and ADF digestibility declined linearly (P less than .01) with increasing dietary FDS. Ether extract digestibility was unchanged due to treatment, but GE digestibility decreased quadratically (P less than .01). The most pronounced decline in GE digestibility occurred when FDS increased from 14 to 21% of the diet. The effects of FDS on corn silage utilization were similar to MSB effects. Oil content and antinutritional factors contributed to detrimental effects. Frost-damaged soybeans should not exceed 14% of corn silage diets fed to growing wethers.     

Soybean protein solubility in potassium hydroxide: an in vitro test of in vivo protein quality

Experiments were conducted to assess protein solubility in .2% KOH as an indicator of soybean protein quality for chicks and pigs and to assess effects of particle size on protein solubility. As the particle size (micron) of soybean meal (SBM) increased, protein solubility (%) decreased (b = -.0206). In two 9-d chick trials, dehulled SBM (48% CP) was subjected to various autoclaving times and then fed as the sole source of dietary protein to young chicks. Increasing autoclaving times from 0 to 40 min at 120 degrees C resulted in a quadratic decrease in protein solubility. A broken-line model was fitted wherein gain:feed of chicks was plotted as a function of protein solubility. The analysis showed no reduction in feed efficiency with solubilities greater than 59 +/- 1.5% (mean +/- SEM). When solubility was below 59%, however, gain:feed decreased 1.5% for each 1% decrease in protein solubility. The third trial (13 d) was conducted with 7.5-kg pigs fed autoclaved SBM (44% CP) as the primary source of protein. Feed efficiency was significantly decreased when protein solubility was less than 66%. This study showed that protein solubility in KOH was a good index of in vivo soybean protein quality, and that it is important to standardize SBM particle size when applying the KOH assay.