生长猪高蛋白豆粕氨基酸回肠可消化率的研究

选用10头健康回肠末端安装简单T型瘘管的杂交(杜×长×大),阉公猪体重(37.8±0.7)kg,采用有重复5×5拉丁方设计,比较4种不同豆粕产品(去皮与带皮高蛋白豆粕,去皮与带皮常规豆粕)在生长猪的氨基酸回肠表观和真消化率。结果表明:豆粕加工类型显著地影响豆粕中氨基酸回肠表观和真消化率,除精氨酸外,去皮豆粕氨基酸回肠表观消化率显著高于带皮豆粕(P<0.05);去皮豆粕必需氨基酸中的组氨酸、亮氨酸、蛋氨酸和苏氨酸均显著高于带皮豆粕(P<0.05)。与常规豆粕相比,高蛋白豆粕中苯丙氨酸、色氨酸、缬氨酸、丙氨酸的回肠表观消化率显著提高(P<0.05),这预示着高蛋白豆粕是生长猪的优良蛋白质和氨基酸来源。     

大豆制品在猪日粮中的应用

大豆制品中氨基酸的生物利用率完整蛋白质中的氨基酸首先必须被消化 ,然后才能被猪利用。猪对大豆蛋白质中的氨基酸有较高的消化率。表 1显示了在小肠末端 (即回肠末端 )测得的常规豆粕、去皮豆粕、加热大豆和二种大豆制品中蛋白质表观消化率系数和真消化率系数。真消化率系数已就内源氨基酸排泄量 (脱落的肠细胞、肠道中的酶以及其它非日粮来源的氨基酸 )作了校正 ,真消化率系数略高于表观消化率系数。　表 1　猪对豆粕中氨基酸的消化率氨基酸豆粕去皮豆粕加热大豆浓缩大豆蛋白离析大豆蛋白回肠表观消化率系数 (% )精氨酸 9190 8997 91组氨…     

中国不同品种菜粕猪回肠氨基酸消化率研究

试验选用 9头 34.5± 2 .1kg的阉公猪 ,在回肠末端安装T型瘘管后按 9× 6不完全拉丁方设计分别饲喂 7种菜粕半纯合日粮、1种豆粕半纯合日粮和 1种酪蛋白日粮 ,以研究中国不同品种菜粕和豆粕回肠氨基酸表观 (真 )消化率。结果表明 ,7种菜粕粗蛋白质和氨基酸 (半胱氨酸除外 )回肠表观 (真 )消化率均显著低于豆粕 (P <0 .0 5 ) ;7种菜粕粗蛋白质和氨基酸回肠表观 (真 )消化率之间存在显著差异 (P <0 .0 5 ) ,这些变异主要是由菜粕中性洗涤纤维和酸性洗涤纤维水平及相应氨基酸含量不同引起的 ;可利用粗蛋白质回肠表观消化率估测多数氨基酸回肠消化率     

科技进展

饲喂生长猪经热处理的豆粕氨基酸的消化率对豆粕进行热处理可以降低胰蛋白酶抑制因子的浓度,但过度加热产生的美拉德反应会破坏豆粕中的氨基酸,进而降低氨基酸的浓度和消化率。本研究的目的是探讨豆粕经热处理后,生长猪对豆粕中氨基酸的表观回肠消化率和标准回肠消化率(SID)的变化。将普通的去皮豆粕分成4组,一组     

饲喂生长猪经热处理的豆粕氨基酸的消化率

对豆粕进行热处理可以降低胰蛋白酶抑制因子的浓度,但过度加热产生的美拉德反应会破坏豆粕中的氨基酸,进而降低氨基酸的浓度和消化率。本研究的目的是探讨豆粕经热处理后,生长猪对豆粕中氨基酸的表观回肠消化率和标准回肠消化率（SID）的变化。将普通的去皮豆粕分成4组,     

日粮酸性洗涤纤维水平对不同品种生长猪氨基酸回肠表观消化率的影响

为研究日粮酸性洗涤纤维(ADF)水平对不同品种生长猪氨基酸回肠表观消化率的影响,试验分别选取4头体重相近、健康去势的烟台黑猪、鲁农2号生长猪,饲喂玉米-豆粕型日粮,采用4×4拉丁方设计,在保持日粮其他养分基本一致的情况下,按日粮ADF含量不同分为3.8%、4.8%、5.8%、6.8%四个处理组。于每期试验的第7天连续收集12 h的食糜测定回肠末端氨基酸表观消化率。结果表明:(1)两品种猪氨基酸回肠表观消化率均与ADF水平呈显著线性负相关(P0.05);(2)ADF水平为3.8%~4.8%对地方品种猪及其配套系氨基酸回肠表观消化率的影响不显著(P0.05),达5.8%及以上时其则受到显著或极显著影响(P0.05或P0.01);(3)除苏氨酸、谷氨酸、天冬氨酸外,猪的品种对其他氨基酸消化率均影响显著或极显著(P0.05或P0.01),相同ADF水平日粮的烟台黑猪氨基酸消化率高于鲁农2号猪;除丙氨酸(P0.05)外,ADF水平对氨基酸回肠表观消化率均影响极显著(P0.01);但二者的互作关系不显著(P0.05)。     

发酵豆粕对鲁烟白猪回肠养分消化率及氮平衡的影响

试验旨在通过筛选得出乳酸杆菌、枯草芽孢杆菌、酵母菌的最佳发酵组合,并通过代谢试验获得发酵豆粕对鲁烟白猪回肠消化率及氮平衡的影响。首先通过L16(43)正交设计试验发酵豆粕,从中筛选出最优组合及其最佳比例。选择体重(40±1.25)kg安装回肠末端简单T型瘘管的健康鲁烟白阉公猪5头,分别饲喂普通日粮(Ⅰ)、3%发酵豆粕日粮(Ⅱ)、0.5%乳酸普通日粮(Ⅲ)、0.2%蛋白酶普通日粮(Ⅳ)、0.5%乳酸+0.2%蛋白酶的普通日粮(Ⅴ),采用5×5拉丁方试验设计,比较各组养分消化率、氨基酸回肠末端表观消化率和氮平衡。结果表明,第Ⅱ组的粗蛋白质消化率、粗脂肪消化率最高,显著高于Ⅰ、Ⅲ、Ⅳ、Ⅴ组(P0.05)。总氨基酸回肠末端表观消化率第Ⅱ组显著高于第Ⅰ、Ⅲ、Ⅳ、Ⅴ组(P0.05)。第Ⅱ组的总氮排出量最低,与Ⅰ、Ⅲ、Ⅳ、Ⅴ组相比分别降低了19.26%、30.88%、38.27%、33.42%(P0.05,P0.01)。氮沉积、氮的生物学价值、氮的沉积率第Ⅱ组均显著高于其他各组(P0.05),说明在鲁烟白生长猪日粮中添加发酵豆粕能显著提高养分消化率,但在日粮中添加发酵产物不能达到同样的效果。     

膨化豆粕与全脂膨化大豆对仔猪生长性能、表观消化率和血清生化指标的影响

试验旨在研究普通豆粕、膨化豆粕和全脂膨化大豆粗蛋白质体外消化率的差异,以及以膨化豆粕和全脂膨化大豆替代玉米-豆粕型基础日粮中部分豆粕对仔猪生长性能、养分表观消化率、血清生化指标的影响。以胃蛋白酶-胰蛋白酶两步消化法测定体外消化率。动物试验选用108头初始体重为（10.10±0.57）kg的42日龄健康杜×长×大仔猪（公母各半）,按区组随机分为3组,每组6个重复,每个重复6头猪。对照组饲喂玉米-豆粕型基础日粮,膨化豆粕组以9.66%膨化豆粕替代对照组日粮中9.66%的豆粕,全脂膨化大豆组以12%全脂膨化大豆替代对照组日粮中9.66%豆粕和2.34%豆油。试验期为28 d。结果表明：膨化豆粕与全脂膨化大豆的体外粗蛋白质消化率均高于普通豆粕（P<0.05）,且膨化豆粕高于全脂膨化大豆（P<0.05）;与对照组相比,膨化豆粕组降低了仔猪耗料增重比（P<0.05）,其他生长性能指标无显著差异;与对照组相比,膨化豆粕组与全脂膨化大豆组均提高了干物质、总能、粗蛋白质、粗脂肪以及有机物的表观消化率（P<0.05）;膨化豆粕组血清中白蛋白含量高于对照组和全脂膨化大豆组（P<...     

马铃薯蛋白粉在仔猪上的营养价值评定

选择体重为(16±1.66)kg PIC仔猪18头,在测定马铃薯蛋白粉(PPM)养分、氨基酸含量的基础上进行消化代谢试验。以PPM和豆粕(SBM)分别作为唯一蛋白源配制半纯合日粮,采用无氮日粮法测定两者猪回肠末端氨基酸的表观消化率和真消化率。结果表明:PPM含消化能18.84MJ/kg,可消化粗蛋白质74.08%,蛋白质生物学效价76.87%,均显著高于豆粕。同时,PPM中大部分氨基酸,尤其是Glu、Lys、Pro等的含量、表观消化率或真消化率显著或极显著高于豆粕,回肠真可消化Glu、Lys、Pro的含量分别为20.67%、5.58%、8.16%,分别比豆粕高194.92%、110.34%、94.87%。可见,PPM的能量和蛋白质氨基酸营养价值明显优于豆粕。     

精油对生长猪蛋白质和氨基酸等回肠末端表观消化率的影响

试验旨在通过采用T型瘘管法,研究精油对生长猪蛋白质和氨基酸等回肠末端表观消化率的影响。试验选用6头(杜×长×大)去势公猪([28.6±1.3)kg],采用3×3双拉丁方试验设计,分别饲喂正对照日粮:玉米-豆粕型基础日粮+抗生素;负对照日粮:无抗基础日粮;精油组日粮:负对照+0.01%精油。每个试验期为7 d,前5 d为适应期,后2 d为食糜收集期。结果表明,在日粮中添加精油可提高(P<0.05)蛋白质、能量、精氨酸、赖氨酸、亮氨酸、色氨酸、蛋氨酸、丙氨酸、总必需氨基酸、总氨基酸的回肠末端表观消化率,并有提高干物质、苏氨酸、天冬氨酸、丝氨酸和酪氨酸表观消化率的趋势(P<0.10)。在日粮中添加0.01%的精油可提高生长猪蛋白质、能量、总必需氨基酸和总氨基酸的回肠末端表观消化率,并有提高干物质表观消化率的趋势。     

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.     

Digestibility of nitrogen and amino acids in soybean meal with added soyhulls

This study was designed to quantify the effect of soyhulls on N and AA digestibilities of soybean meal for growing pigs. Soyhulls were incorporated into 17% CP diets containing 33.25% soybean meal (SBM) at 0, 3, 6, or 9% (as-fed basis) and fed to 35-kg barrows to determine their effect on apparent and true digestibility of DM, GE, N, and AA measured at the terminal ileum. Positive and negative control diets containing 1.05% lysine were formulated with 35% SBM and 27% soy protein concentrate (SPC), respectively. A low-protein, casein-based diet was used to estimate endogenous AA losses. Soyhulls were incorporated into experimental diets at the expense of cornstarch, and SBM levels were adjusted to accommodate the contribution of CP from soyhulls. Fourteen pigs were surgically fitted with simple T-cannula at the distal ileum and fed the seven semipurified cornstarch diets based on a replicated 7 x 7 Latin square design. Each period lasted 7 d, with diet acclimation from d 1 to 5 and ileal sample collection for 12 h on d 6 and 7. Feed was offered at a level of 90 g/kg BW(0.75) in two equal portions at 0800 and 2000. Apparent ileal digestibilities of DM and GE decreased approximately six percentage units with the addition of soyhulls (linear, P < 0.05), whereas N was not affected. Both apparent and true ileal digestibilities of arginine, histidine, lysine, phenylalanine, aspartic acid, serine, and tyrosine also exhibited a decrease (linear, P < 0.05) of up to five percentage units with the addition of soyhulls. True ileal lysine digestibility of SBM decreased from 90.3 to 87.7% with the addition of 9% soyhulls. The endogenous nutrient fraction measured at the distal ileum was rich in proline, glutamic acid, and glycine, with losses greater than 1,000 mg/kg of DMI for each AA, and contained minimal amounts of tryptophan, methionine, and cystine. The current data suggest that a 0.2% decrease in some true ileal indispensable AA digestibilities may result with each 1% increase in soyhull inclusion in semipurified diets containing SBM as the sole source of AA as fed to growing pigs.     

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.     

The influence of soy oligosaccharides on apparent and true ileal amino acid digestibilities and fecal consistency in growing pigs

Fourteen ileally cannulated pigs (BW = 35 +/- 2 kg) were randomly allotted to a replicated 7 x 7 Latin square design experiment to evaluate the influence of the soybean oligosaccharides (OS), raffinose and stachyose, on ileal nutrient digestibility and fecal consistency. Semipurified diets containing soy protein concentrate (SPC) or soybean meal (SBM) as the sole protein sources were fed. Soy solubles (SS), a by-product of SBM processing containing 3.5% raffinose and 11.5% stachyose, were used to increase dietary raffinose and stachyose concentrations. The seven dietary treatments were SPC, SPC + 9% SS, SBM, SBM + 9% SS, SBM + 18% SS, SBM + 24,000 U alpha-galactosidase enzyme preparation/kg diet, and a low-protein casein (LPC) diet used to calculate true digestibility. Diets, with the exception of the LPC diet, were formulated to contain 17% CP. All diets contained 0.5% chromic oxide as a marker for ileal digestibility determination. The experimental periods were divided into a 5-d diet adaptation followed by 2-d of ileal digesta collection. Diets and digesta were analyzed for DM, N, Cr, amino acids (AA), raffinose, and stachyose. Fecal consistency was determined on d 6 and 7 of each experimental period. The apparent and true ileal AA digestibilities were not different (P < 0.05) for the SPC and SBM control diets. When SS was added to the SPC diet, apparent and true N and AA digestibilities were depressed (P < 0.05) with the exception of Trp and Pro. The apparent and true ileal N and AA digestibilities were not different (P > 0.05) between the SBM control and SBM + 9% SS diets with the exception of Glu. There was a linear decrease (P < 0.05) in apparent and true DM, Val, Gly, and Tyr digestibilities when increasing levels of SS were added to the SBM diet. The addition of alpha-galactosidase did not improve apparent or true ileal N or AA digestibilities except for apparent and true Val and Tyr. Ileal raffinose digestibility was improved (P < 0.05) by addition of a-galactosidase, but was not affected by any other dietary treatment. Ileal stachyose digestibility was not affected (P > 0.58) by treatment. Fecal consistency likewise was not affected (P > 0.36) by dietary treatment. In conclusion, soy OS reduced nutrient digestibilities, but the reductions were small, ranging from approximately 1.1 to 7.4 percentage units. This suggests that other factors may be negatively impacting SBM digestibility.     

Amino acid digestibility in heated soybean meal fed to growing pigs

Heat treatment of soybean meal (SBM) is necessary to reduce the concentration of trypsin inhibitors, but excessive heat treatment may reduce AA concentration and digestibility because AA can be destroyed by the Maillard reaction. The objective of this experiment was to determine the effects of heat treatment of SBM on apparent ileal digestibility and standardized ileal digestibility (SID) of AA by growing pigs. A source of conventional dehulled SBM (48.5% CP) was divided into 4 batches. One batch was not additionally heated, 1 batch was autoclaved at 125°C for 15 min, 1 batch was autoclaved at 125°C for 30 min, and 1 batch was oven-dried at 125°C for 30 min. Four SBM-cornstarch diets were formulated, and each of the 4 batches of SBM was used as the sole source of dietary AA in 1 diet. A N-free diet was used to estimate basal endogenous losses of AA. Ten growing barrows with an initial BW of 25.3 ± 2.0 kg were individually fitted with a T-cannula in the distal ileum. Pigs were allotted to treatments in a replicated 5 × 5 balanced Latin square design with 5 diets and 5 periods. Each period lasted 7 d, and ileal digesta were collected on d 6 and 7 of each period. Results of the experiment indicated that the apparent ileal digestibility and SID of CP and all AA decreased linearly (P < 0.01) as the time of autoclaving increased from 0 to 30 min. The concentration of furosine and the color of samples of SBM indicated that autoclaving resulted in a Maillard reaction in the SBM. However, oven drying at 125°C for 30 min did not change (P > 0.10) the SID of CP and AA in the SBM or the furosine concentration, and the color in the oven-dried sample indicated that this sample was not heat damaged. In conclusion, the digestibility of all AA in autoclaved SBM is linearly reduced as the autoclaving time increases from 0 to 30 min. The reason for these changes is most likely that autoclaving at 125°C results in Maillard reactions in SBM.     

固态发酵对复合蛋白质饲料营养价值改善效果的研究

本文旨在研究同态发酵对复合蛋白质饲料(CPF)营养成分和养分利用效率的改善效果.将产朊假丝酵母、枯草芽孢杆菌和乳酸杆菌接种到CPF后发酵3 d,干燥制得发酵复合蛋白质饲料(FCPF).在测定豆粕(SBM)、CPF、FCPF常规养分和氨基酸含量基础上进行消化代谢试验.选择体重为(24.36±1.78)kg的杜×长×大生长猪24头,随机分为4组,每组6个重复,每个重复1头猪,分别饲喂无氮日粮和以SBM、CPF及FCPF作为唯一蛋白质源配制的半纯合日粮,采用无氮日粮法测定SBM、CPF和FCPF对生长猪的蛋白质、能量消化利用率以及氨基酸回肠消化率.预试期4 d,正试期4 d.结果表明:固态发酵极显著提高了FCPF的粗蛋白质、真蛋白质、钙和总磷含量(P<0.01);除精氨酸外,氨基酸含量均有所提高.与CPF相比,FCPF蛋白质消化利用率和能量消化率均极显著升高(P<0.01);氨基酸表观消化率显著或极显著的升高(P<0.05或P<0.01);除Gly以外,FCPF各氨基酸真消化率均显著或极显著的升高(P<0.05或P<0.01).FCPF大部分营养特性接近或优于SBM.由此可知,固态发酵可改善CPF的营养特性,提高其在20～50 kg生长猪上的养分消化利用率.     

Additivity of values for apparent and standardized ileal digestibility of amino acids in mixed diets fed to growing pigs

The objective of this experiment was to determine whether the digestibility of CP and AA in a mixed diet fed to growing pigs is better predicted when based on standardized ileal digestibility coefficients (SID) or apparent ileal digestibility coefficients (AID). Eight growing pigs (initial BW = 92.1 +/- 3.19 kg) were surgically equipped with a T-cannula in the distal ileum and arranged in an 8 x 8 Latin square design with eight diets and eight periods. Three of the diets contained corn, soybean meal (SBM), or canola meal (CM) as the sole source of CP and AA. Four mixed diets also were formulated using corn and soybean meal (CS); corn and canola meal (CCM); soybean meal and canola meal (SCM); or corn, soybean meal, and canola meal (CSCM). A N-free diet was used to measure the basal ileal endogenous losses (IAAend) of CP and AA. Pigs were fed each of the eight diets during one 7-d period, and ileal digesta were collected during two 10-h periods on d 6 and 7. The AID values were calculated for CP and AA in all diets, except the N-free diet. By correcting the AID for IAAend, the SID for CP and AA in each of the seven protein-containing diets were calculated. As expected, the AID for CP and the majority of AA were greater in SBM than in corn and CM (P < 0.05); however, the SID for CP and most AA did not differ between corn and SBM. For the majority of the AA, SID were less (P < 0.05) in CM than in the other two ingredients. Using the AID and the SID that were measured for CP and AA in corn, SBM, and CM, the AID and the SID in the four mixed diets were predicted and compared with the measured values for these diets. For the three mixed diets containing corn, the measured AID for CP and most AA were greater (P < 0.05) than the predicted AID, but with a few exceptions, no differences between predicted and measured values for SID were observed. For the diet based on SCM, there were no differences between predicted and measured values regardless of the procedure used, except for the AID of Ser. The results of this experiment demonstrate that the digestibility coefficients for a mixed diet containing low-protein feed ingredients, such as corn, are more accurately predicted using SID than AID.     

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.     

Effect of soybean meal particle size on amino acid and energy digestibility in grower-finisher swine

A study was conducted using the ileal digestibility technique with grower-finisher pigs to evaluate the effects of particle size reduction of soybean meal (SBM) on amino acid and energy digestibility. Soybean meal was processed through a hammer mill to achieve average particle sizes of 900, 600, 300, and 150 microm. The treatments included the use of two soybean meal sources and soy protein concentrate. One source of SBM was ground to four different particle sizes (i.e., 949, 600, 389, 185); a second source was a common SBM source used in other trials (i.e., 800 microm). The soy protein concentrate had an average particle size of 385 microm. A low-protein (5% casein) diet was fed to determine endogenous amino acid losses. This experiment was conducted in a 7 x 7 Latin Square design in two replicates using 14 crossbred barrows ([Landrace x Yorkshire] x Duroc) that averaged 28 kg BW and 60 d of age. Animals were surgically fitted with a T-cannula at the distal ileum. Treatment diets were fed in meal form, initially at 0.09 kg BW(0.75) and at graded increases at each subsequent period. Pigs within replicate were fed a constant quantity of their treatment diet for a 5-d adjustment period followed by a 2-d collection of ileal digesta samples. Apparent and true digestibility of amino acids was calculated by use of chromic oxide (0.5%) as an indigestible marker. Apparent digestibility of isoleucine, methionine, phenylalanine, and valine increased linearly (P < 0.05) as particle size decreased. True digestibility of isoleucine, methionine, phenylalanine, and valine increased linearly (P < 0.05) as particle size decreased. When the essential amino acids were averaged, apparent digestibility increased (P < 0.10) from 83.5% to 84.9% as particle size decreased, whereas, nonessential amino acid digestibility increased only slightly (P > 0.15). Essential amino acid true digestibility increased numerically from 91.0% to 92.4% as particle size decreased. Energy digestibility was not affected by particle size (P > 0.15). These results suggest that a reduction in particle size of soybean meal resulted in a small increase in the digestibility of its amino acids with the essential amino acids being affected more than the nonessential amino acids. The largest improvement in digestibility, however, was obtained when the particle size was reduced to 600 microm.     

Regional and processor variation in the ileal digestible amino acid content of soybean meals measured in growing swine

To assess differences in soybean meal quality related to region of production, researchers in Illinois, Kansas, North Carolina, The Netherlands, and Ohio collected four soybean meal samples processed locally at least 15 d apart. These samples were assayed for ileal amino acid digestibility by pigs using a common soybean meal and a soy protein concentrate as references, and a low-protein casein diet for determination of endogenous amino acid losses. Digestibility was determined at each university using seven barrows surgically fitted with ileal cannulas in a 7 x 7 Latin square design. The experimental diets contained 17% CP from the test material except for the low-protein casein diet. Animals were fed twice daily, 12 h apart, at a level of 45 g x kg(-0.75) BW for each meal. Following a 5-d adaptation period, ileal digesta were collected for two 12-h periods for 2 d to be used for determination of ileal digestibility. Variation in amino acid digestibility was very small among and within sites and was much smaller than variation in the concentration of amino acids. Among sites, samples from The Netherlands had less total and thus digestible lysine and methionine than the U.S. samples (P < 0.05). The soybean meals tested in this experiment were approximately 4% higher in amino acids than that reported in the NRC (1998). True (standardized) digestibilities, however, were very similar to NRC values except for cysteine and threonine, which were 5 and 3 percentage points lower in this experiment, respectively. In conclusion, soybeans grown in the United States and locally processed into soybean meal were very similar in nutritional composition. Soybean meals produced in The Netherlands were lower in lysine and methionine (P < 0.05) but had a digestibility similar to that produced in the United States.