Induced non-enzymatic browning of soybean meal. II. Ruminal escape and net portal absorption of soybean protein treated with xylose

Non-enzymatic browning was tested as a means of increasing ruminal escape of soybean meal N. Soybean meal was treated with xylose (3 mol/mol SBM-lysine), sodium hydroxide (pH 8.5) and enough water to achieve an 83% dry matter mixture and then heated at 150 C for 30 min (XTS-30). Trial 1 evaluated ruminal escape of N from XTS-30 compared with commercial soybean meal (CS) or urea (U) in a replicated 3 X 3 Latin square design using six duodenally cannulated Angus X Hereford steers (24.7 kg). Duodenal flow of dietary N was higher (P less than for steers fed XTS-30 (47.9 g/d) than for steers fed CS (39.5 g/d). The ruminal escape estimate for XTS-30 (33.7%) was higher (P less than .10) than CS (13.1%), whereas total tract apparent N digestibility was not different among treatments. In trial 2, net portal absorption of alpha-amino N was measured in Finnsheep X Suffolk ram lambs (24.7 kg) fed U, CS or XTS-30 in a 3 X 3 Latin square design. Portal blood flow was measured by primed, continuous infusion of para-aminohippuric acid. Portal blood flow was lower (P less than .05) for U.fed lambs than for lambs fed CS or XTS-30, and tended to be lower for lambs fed CS than those fed XTS-30. Net portal absorption of alpha-amino N tended to be lowest for lambs fed U (281 mmol/d) and highest for lambs fed XTS-30 (578 mmol/d). The results are interpreted to show that non-enzymatic browning increased flow of soybean meal N to the intestine.     

Induced non-enzymatic browning of soybean meal. I. Effects of factors controlling non-enzymatic browning on in vitro ammonia release

Non-enzymatic browning was tested as a means of suppressing degradation of soybean meal (SBM) by ruminal microbes in five trials with in vitro ammonia release as the response criterion. Treatments imposed on SBM included reducing sugar source (xylose, glucose, fructose and lactose), reducing sugar level (1, 3 and 5 mol/mol SBM-lysine), pH (6.5, 8.5 and 10.0), dry matter (DM) content (65, 70, 75, 80, 85 and 90%) and varying lengths of heating time (0 to 90 min) at 150 C. Samples heated under conditions that promoted non-enzymatic browning gave greater (P less than .01) ammonia release suppression that when SBM was heated without these treatments. Xylose was the most reactive sugar, but extended heating of SBM containing glucose, fructose or lactose resulted in ammonia release similar to xylose. Increasing sugar level from 1 to 5 mol/mol SBM-lysine caused linear decreases (P less than .01) in ammonia release for xylose, glucose and fructose, but not lactose. Ammonia release was higher (P less than .01) at pH 6.5 than pH 8.5 and 10.0, and higher (P less than .01) at pH 9.5 than pH 10.0. Rate of non-enzymatic browning decreased when samples containing greater than 80% DM were heated. These results are interpreted to show that controlled non-enzymatic browning may be effective for reducing ruminal degradation of SBM.     

甲醛处理生豆饼对绵羊十二指肠中微生物氮、过瘤胃蛋白氮流量及对氮利用率的影响

用4只生长羯羊,采用4×4拉丁方试验设计,测定甲醛处理(甲醛/蛋白质为0、0.3%、0.6%、1.2%)生豆饼的影响.结果表明,用甲醛0～0.6%水平处理时,瘤胃液中NH3-N浓度差异不显著,而1.2%甲醛水平使NH3-N浓度显著降低(P<0.05).甲醛处理使日粮中过瘤胃蛋白氮量增加(P<0.05).用0～0.6%甲醛处理生豆饼对十二指肠食糜中微生物氮(MN)产量,氮在瘤胃后和整个消化道的消化率无影响(P>0.05),而1.2%甲醛用量,则显著降低(P<0.05).十二指肠中非氨态氮(NAN)流量,0.6%甲醛用量高于其它三个处理组(P<0.05),在四个处理组中,用0.6%甲醛处理生豆饼饲喂试羊,其氮的沉积率最高(P<0.05).     

Effect of acid and alkali treatment of soybean meal on nitrogen utilization by ruminants

Soybean meal (SBM) was treated with acid or alkali to determine effects on N solubility, in vitro NH3-N accumulation, in situ N degradability, and N digestion and retention in growing lambs. The following SBM treatments resulted in decreased (P less than .05) N solubility and in vitro NH3-N accumulation compared with control SBM: spraying with 2.5 or 5% acetic or propionic acid, soaking in .5 N HCl, .5 N NaOH or .5 N propionic acid followed by air drying, and soaking in H2O, .5 N HCl or .5 N propionic acid followed by drying at 100 C. In situ residual N was determined for SBM subjected to the above treatments. Soybean meal sprayed with 2.5 or 5% acetic or propionic acid had greater (P less than .05) in situ residual N after 4, 8 and 12 h of incubation than control SBM. Soybean meal soaked in .5 N HCl or .5 N NaOH and air-dried, and soaked in H2O, .5 N propionic acid or .5 N HCl and dried at 100 C had greater (P less than .05) in situ residual N after 4, 8, 12 and 24 h of incubation than control SBM. In a lamb N balance trial, SBM treated by spraying with 5% acetic or propionic acid or by soaking in .5 N NaOH did not result in reduced N digestion compared to control SBM. Feeding SBM soaked in .5 N NaOH resulted in a 39% increase (P less than .05) in N retention compared with control SBM (5.21 vs 3.74 g/d, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

Alternate day supplementation of corn stalk diets with soybean meal or corn gluten meal fed to ruminants.

Four experiments were conducted to determine the effect of adding corn gluten mean (CGM) or soybean meal (SBM) at 24- or 48-h intervals to diets based on corn stalks. In each experiment corn stalks was the primary diet ingredient fed to wethers or steers. Monensin was also fed to determine whether its effects on ruminal fermentation would improve the efficiency of N utilization under these conditions. Evaluation criteria included ruminal fermentation characteristics, DM intake and utilization, N balance in sheep, and steer feedlot performance. Ruminal ammonia nitrogen (NH3 N) concentrations measured over time were higher (P < .05) when diets contained SBM. Diet did not influence (P > .10) total VFA concentrations in ruminal fluid. Differences in diurnal shifts in ruminal NH3 N and total VFA due to protein source resulted in diet x hour interactions (P < .05). Dry matter intake response to protein source and frequency of supplement feeding was variable. Dry matter digestibility and nitrogen digestibility were not affected (P > .10) by protein source or feeding interval. The 48-h interval feeding of CGM was favorable compared with 24-h interval feeding (P < .05). The opposite response occurred with SBM, resulting in a diet x feeding interval interaction (P < .05). Nitrogen retention was greater (P < .05) when CGM was fed and with alternate day feeding. Diets that contained CGM supported higher (P < .05) ADG and gain/feed than diets that contained SBM when fed to steer calves. Alternate day feeding of supplements that contained monensin was detrimental to steer performance under the conditions of these experiments. Corn gluten meal is an effective substitute for SBM when alternate day protein supplementation is practiced.     

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)     

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.     

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.     

用戊糖处理豆粕对蛋白质保护效果的研究

试验研究戊糖浓度(1%、3%)、加热温度(90、105、120、140℃)及加热时间(20、40、90min)对豆粕蛋白质的保护效果。试验为三因素多水平完全随机试验设计,共24个处理组。采用瘤胃尼龙袋法和三步法分别评定各处理组的瘤胃蛋白降解率和小肠消化率。结果表明:戊糖浓度、加热温度和加热时间都影响豆粕蛋白保护的效果,蛋白瘤胃降解率随着戊糖浓度的增加、加热时间的延长、加热温度的升高而逐渐降低。在处理条件140℃、90min、3%时获得最低的瘤胃蛋白降解率。     

Digestibility of phosphorus by growing pigs of fermented and conventional soybean meal without and with microbial phytase

An experiment was conducted to test the hypothesis that the apparent total tract digestibility (ATTD) and the standardized total tract digestibility (STTD) of P in fermented soybean meal (FSBM) are greater than in conventional soybean meal (SBM-CV) when fed to growing pigs. Four diets were formulated to contain FSBM or SBM-CV and either 0 or 800 units/kg of microbial phytase. The only sources of P in these diets were FSBM and SBM-CV. A P-free diet to estimate basal endogenous losses of P was also formulated. Thirty barrows (initial BW: 14.0 ± 2.3 kg) were placed in metabolism cages and allotted to 5 diets in a randomized complete block design with 6 pigs per diet. Feces were collected for 5 d after a 5-d adaptation period. All samples of ingredients, diets, and feces were analyzed for P, and values for ATTD and STTD of P were calculated. Results indicated that the basal endogenous P losses were 187 mg/kg of DMI. As phytase was added to the diet, the ATTD and STTD of P increased (P < 0.01) from 60.9 to 67.5% and from 65.5 to 71.9%, respectively, in pigs fed FSMB. Likewise, addition of phytase to SBM-CV increased (P < 0.01) the ATTD and STTD of P from 41.6 to 66.2% and from 46.1 to 71.4%, respectively. The ATTD and STTD of P were greater (P < 0.01) in FSBM than in SBM-CV when no phytase was used, but that was not observed when phytase was added to the diet (soybean meal × phytase interaction, P < 0.01). In conclusion, the ATTD and STTD of P in FSBM was greater than SBM-CV when no microbial phytase was added, but when phytase was added to the diets, no differences between FSBM and SBM-CV were observed in the ATTD and STTD of P.     

含水量对糖处理豆粕过瘤胃蛋白影响的研究

本试验以3头装有永久性瘸胃瘘管的中国荷斯坦奶牛为试验动物,采用尼龙袋法研究在不同水分含量下(15%、20%、25%、30%、35%)葡萄糖处理豆粕,在奶牛瘤胃内不同时间点干物质(DM)、粗蛋白质(CP)消失率及其动态降解率的作用效果.结果表明:在不同时间点下,随着含水量的增加,DM、CP消失率先降低后升高,所有处理组与对照组差异均显著(P<0.05),DM、CP有效降解率降低最高分别达18.50%和36.10%,含水量在20%以下,DM、CP有效降解率最低,表明以含水量20%的葡萄糖加热处理豆粕保护效果最好.     

Energy utilization of sodium hydroxide treated or untreated straw supplemented with protein or concentrates by adult sheep. 2. Rumen digestion

NaOH treated (T) or untreated (UT) barley straws were supplemented either with protein (P) or with concentrates based on maize (M) or beet pulp (BP), the two last at rates of 25 and 50% of the diet. Each of the 10 diets was fed to two sheep ad libitum. Two diets were also fed at limited intakes. For these 12 diets in sacco cellulolytic activity in the rumen and ruminal fermentation were measured. Cellulolytic activity was measured with the studied straws, so that their digestion rate was also determined. NaOH treatment increased rate of digestion of straw, while high levels of concentrates decreased it. In contrast NaOH treatment and high levels of concentrate decreased cellulolytic activity but neither type of concentrate nor limitation of intake altered it. NaOH treatment only slightly modified pH because a higher level of VFA in rumen balanced NaOH presence. An important negative effect on pH of high levels of concentrate was observed, but there was no effect or type of concentrate or limitation of intake. Fermentation pattern was only slightly influenced by studied factors: +2.2 units of butyric acid and -2.1 units of acetic acid with treated straw; lower level of acetic acid occurred when concentrate was increased, especially for maize. Limitation of intake increased acetic acid molar proportion.     

Effects of heat and alcohol treatments of soybean meal on nitrogen utilization by sheep

Soybean meal (SBM) was treated with aqueous solutions of ethanol or propanol at room temperature or at 80 C to study treatment effects on SBM-N solubility and utilization by sheep. Soybean meal was soaked in an excess of 70% (v/v) ethanol at 80 C (ET-80), 70% ethanol at 23 C (ET-23) or 70% propanol at 80 C (PR-80). Nontreated SBM and nontreated SBM heated at 80 C without alcohol treatment (NT-80) served as controls. Nitrogen solubility in McDougall's buffer was lowest (P less than .05) for PR-80 and ET-80 (2.2 and 4.7% of total N, respectively), intermediate (P less than .05) for ET-23 (9.0%), greater (P less than .05) for nontreated SBM (36.2%) and highest for NT-80 (40.2%). In an situ study using three ruminally cannulated cows and two bags per treatment per animal per removal time, more (P less than .05) N remained in in situ bags after 3, 6, 9 and 12 h incubation for ET-23, ET-80 and PR-80 than for nontreated SBM and NT-80. A lamb metabolism trial, using 15 lambs in each of two periods, compared nontreated SBM, ET-23, ET-80, PR-80 and urea as N supplements. Nitrogen retention was higher (P less than .02) for lambs fed SBM treatments compared with urea. When the same N supplements were fed to wethers in a 5 X 5 Latin square experiment and duodenal N flow was measured, non-ammonia non-bacterial N flow was higher (P less than .07) for wethers fed SBM treatments than for wethers fed urea.(ABSTRACT TRUNCATED AT 250 WORDS)     

Performance and carcass characteristics of young cattle fed with soybean meal treated with tannins

This study aimed to evaluate the effects of replacement of soybean meal (SBM) with soybean meal treated with tannin (SBMT) on the intake, digestibility, performance and characteristics of the carcasses of young cattle fed a high‐concentrate diet. Forty‐two Nellore bulls with body weight of 244.5 ± 4.99 kg were used. Diets had the inclusion of 7.5% SBM, with a proportion of that SBM (0, 33, 66 or 100%) replaced for SBMT; and other treatment (SBMT + urea) just with 2.5% of SBM which was treated with tannins. Seven animals were randomly selected and slaughtered, and the remaining animals were distributed on treatments and remained for 112 days. After, all animals were slaughtered. There was a linear decline in dry matter intake (P = 0.026) when SBM was replaced with SBMT. No decrease in carcass weight (P > 0.05) was observed. The efficiency of carcass weight gain showed a quadratic function effect (P = 0.049). There were changes in carcass gain composition when SBMT was added (P < 0.05), with an increase in muscle and reduction in fat deposition. The use of SBMT in place of SBM causes changes in body gain composition in animals and reduces DM intake by the animals, achieving a better feed conversion efficiency.     

甲醛处理豆粕对蛋白质瘤胃降解及活体外瘤胃发酵的影响

通过尼龙袋试验和产气量试验研究甲醛处理大豆粕对瘤胃蛋白质降解率、产气量和活体外瘤胃发酵参数的影响。3个处理分别为对照组、处理Ⅰ和处理Ⅱ,其中处理Ⅰ、处理Ⅱ的甲醛添加量分别占大豆粕粗蛋白质(CP)0.6%和1.2%。研究结果表明:与对照组相比,处理Ⅰ和处理Ⅱ的干物质及蛋白质的降解率及降解速度显著下降(P<0.001),快速降解组分的比例和有效降解率显著下降,慢速降解组分比例显著提高(P<0.001),但两处理组之间干物质降解速度和蛋白质慢速降解组分比例均无显著差异(P>0.05)。与对照组相比,处理Ⅰ与处理Ⅱ的72h产气量和理论最大产气量均显著升高(P<0.001),而产气速度显著降低(P<0.005);甲醛处理对活体外瘤胃72h发酵的pH值、NH3-N浓度没有显著影响(P>0.05),但发酵液中丙酸摩尔比例显著上升(P<0.05),从而导致乙酸/丙酸降低。两个处理组活体外24h发酵液中甲醛浓度分别为0.994μg/mL和0.370μg/mL;而72h发酵液中甲醛浓度分别为0.410μg/mL和0.141μg/mL。本试验结论:甲醛处理能有效降低蛋白质在瘤胃内的降解率,并改善活体外发酵参数,其中甲醛添加量以占0.6%CP的处理更为有效。     

Digestibility and utilization of energy and protein in screened swine waste solids by gestating gilts

Two balance experiments were conducted using 24 gestating gilts in each experiment to determine the apparent digestible and metabolizable energy content, apparent digestible protein content, net protein utilization and apparent biological value of screened swine waste solids (SSWS). Waste solids were collected by screening flushed whole swine waste using a vibrating screen separator. Waste solids containing 30% dry matter were collected daily and mixed with a basal diet. In Exp. 1, SSWS were fed at a level estimated to replace 0, 25, 50 or 86% of the metabolizable energy content of the basal diet. Digestibility of the energy in the total diet decreased quadratically (85.2, 70.2, 60.7 and 58.3%, respectively, P less than .0001) with increasing SSWS. The percentages of gross energy supplied by SSWS that were digested and metabolized, as calculated by difference, were not affected significantly by the amount of SSWS fed (48.0, 48.0, 53.2% digested and 45.1, 45.2, 48.1% metabolized, respectively, for 25, 50 and 86% of gross energy intake from SSWS). The mean digestible and metabolizable energy contents of SSWS for gestating gilts were determined to be 1,998 and 1,854 kcal/kg dry matter. In Exp. 2, gilts were fed SSWS to replace 0, 25 or 50% of the crude protein in the basal diet. Apparent digestibility of the protein in the total diet decreased linearly (83.8, 66.1 and 51.1%, respectively, P less than .0001) as the amount of SSWS in the diet increased. The apparent digestibility of the crude protein in SSWS, as calculated by difference, was -4.23 and 10.1% for the 25 and 50% level of replacement.(ABSTRACT TRUNCATED AT 250 WORDS)     

Energy utilization of sodium hydroxide treated or untreated straw supplemented with protein or concentrates by adult sheep. 1. Feed intake, digestibility, metabolizability and net energy value

NaOH treated (T) or untreated (UT) barley straws were supplemented either with protein (P) or with concentrates based on maize (M) or beet pulp (BP) at rates of 25 or 50% of the diet. Each of the 8 diets was fed to 8 sheep near ad libitum and near maintenance. Energy balances were determined by indirect calorimetry. Straw and feed intakes were doubled by the alkali treatment (P, BP25 and BP50 diets) or increased by 83% (M25 diet) and 63% (M50 diet). Near maintenance, energy digestibility (dE) and metabolizability (q) of the straw were improved by 36% and 40% respectively in the P diet and by 28% and 25% on average in the other diets. Ad libitum feeding reduced energy digestibility of treated straw by 11% and metabolizability by 5% on average in the BP25, BP50 and M25 diets; in the case of the M50 diet dE of the T straw was depressed by 30% and the beneficial effect of the alkali treatment was suppressed. The efficiency of metabolizable energy (ME) of the treated straw diets for maintenance was also raised by 9% (P diet) to 3% (M50 diet) and the corresponding net energy content of the treated straw was increased by 58 to 30%. ME efficiencies of the diets for fattening ranged from 44.0 to 52.8%. Energy retention of sheep was considerably increased by the alkali treatment of straw, whereas their maintenance requirement could not be met by the untreated straw diets supplemented with 25% concentrate.     

Influence of guanidination on apparent ileal digestibility of amino acids in pigs fed diets with soybean meal, rapeseed meal or peas as a protein source

The objective of this study was to determine the effect of guanidination, the conversion of dietary lysine to homoarginine, on the apparent ileal digestibilities (AID) of amino acids (AA) from 3 protein sources in diets for pigs. Six barrows, initial body weight of 18 ± 1.5 kg, fitted with a simple T-cannula at the distal ileum, were fed one of three corn starch-based diets that contained 18% crude protein (CP) from soybean meal, rapeseed meal or peas for an experimental period of 10 d according to a repeated 3 × 3 Latin square design. On d 9 of each experimental period, the pigs were fed one meal of the guanidinated test meals, which corresponded to their respective diets. In the test meals, 50% of the protein source in each diet was replaced, on an equal weight basis, with a guanidinated source. Guanidination increased the content of CP by 190, 116 and 28 g kg^− 1 for soybean meal, rapeseed meal and peas, respectively. With the exception of lysine, the AID of CP and AA were 2.2 to 8.2 percentage units (pu) higher in the test meal than in the soybean meal diet. Other than arginine and isoleucine, the differences were significant (P < 0.05) for all indispensable AA. With the exception of lysine, the AID of CP and AA were 3.8 to 11.9 pu higher in the test meal than in the diet with peas. The differences were significant (P < 0.05) for all indispensable AA. Other than lysine, glycine and proline, the AID of CP and AA were slightly higher, 0.1 to 4.3 pu, in the test meal than in the rapeseed meal diet. Of the indispensable AA, the differences were significant (P < 0.05) for arginine, leucine and phenylalanine. The AID of lysine was 10.9 pu lower (P < 0.05) in the test meal than in the rapeseed meal diet, 61.5 vs. 72.4%, indicating that guanidination of rapeseed meal was not uniform and random. The increase in the AID of CP and AA after guanidination may result from solubilisation of protein and degradation of antinutritional factors such as fiber, trypsin inhibitors and tannins.     

菌酶协同处理豆粕制备饲用小肽的研究

以小肽含量为指标研究了芽孢杆菌、酵母菌和中性蛋白酶协同发酵、酶解处理豆粕制备饲用小肽的工艺条件。结果表明:菌酶协同处理豆粕的最佳条件为混合菌接种量1.5%、加酶量450 U/g、料水比1∶1.4、发酵温度40℃、发酵时间48 h。在此条件下,豆粕经菌酶协同处理后,小肽含量从11.40 mg/g提高到199.65 mg/g,粗蛋白质含量从47.62%提高到56.72%。     

Performance and digestibilities of beef cattle fed diets supplemented with either soybean meal or roasted soybeans and implanted with Synovex.

Two 160-d feedlot experiments, each consisting of 20 Angus-Hereford steers (216 +/- 5 kg BW, Exp. 1; 258 +/- 5 kg BW, Exp. 2) and 20 Angus-Hereford heifers (208 +/- 5 kg BW, Exp. 1; 236 +/- 5 kg BW, Exp. 2), were used to investigate the effects of supplementing diets with either roasted soybeans (RSB, roasted at 127 degrees C for 10 min) or soybean meal (SBM) and implanting or not implanting with an estrogenic growth promoter (SYN; Synovex-S, 20 mg of estradiol benzoate plus 200 mg of progesterone or Synovex-H, 20 mg of estradiol benzoate plus 200 mg of testosterone) on performance. The cattle were fed a basal diet of 15% orchardgrass silage, 15% corn silage, and 70% corn-based concentrate. Treatments were 1) no SYN and fed a SBM-supplemented diet, 2) no SYN and fed a RSB-supplemented diet, 3) SYN and SBM, and 4) SYN and RSB. Cattle in the SYN groups were reimplanted at 80 d. Four additional Angus-Hereford steers were used in a digestion and nitrogen balance experiment conducted during the first half of Exp. 1. For the total 160-d feedlot experiments, DMI for RSB compared with SBM was lower (P < .01; 8.5 vs 9.2 kg/d, SEM = .07) and ADG/DMI tended to be higher (P < .10; 165 vs 157 g/kg, SEM = 1.3). Final BW of steers fed RSB was similar (P > .10) to that of steers fed SBM (473 vs 478 kg, SEM = 5.6), as was ADG (1.39 vs 1.43 kg/d, SEM = .02). Dry matter intake for SYN-implanted steers was higher (P < .01) than for steers not implanted (9.2 vs 8.5 kg/d). Likewise, final BW (491 vs 460 kg) and ADG (1.49 vs 1.33 kg/d) were higher (P < .01), and ADG/DMI (166 vs 157 g/kg) tended to be higher (P < .10), for SYN-implanted steers than for steers not implanted. During the more rapid muscle growth period (0 to 80 d), DMI for RSB compared with SBM was lower (P < .01; 7.8 vs 8.6 kg/d, SEM = .07) and ADG/DMI was similar (P > .10; 181 vs 172 g/kg, SEM = 1.8). Dry matter intake for SYN-implanted steers was higher (P < .05) than for steers not implanted (8.4 vs 8.0 kg/d), as was ADG/DMI (P < .01, 182 vs 171 g/kg). During this more rapid growth period, the supplement x implant interaction for ADG was significant (P < .05; 1.35, 1.36, 1.59, and 1.44 kg/d for Treatments 1, 2, 3, and 4, respectively, SEM = .04). There were no differences in digestibilities or N balance. The results suggest that there is no improvement in performance under feedlot conditions when RSB replaces SBM in the diet of beef cattle, and, in young cattle, RSB may reduce the response expected by an estrogenic growth promoter.