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.     

Factors affecting the variability in ileal amino acid digestibility in corn distillers dried grains with solubles fed to growing pigs

Two experiments were conducted to compare the ileal digestibility of AA in distillers dried grains with solubles (DDGS) sourced from different regions (IL, MN, KY), to compare AA digestibility in DDGS and in distillers dried grains (DDG) and to compare AA digestibility in DDGS from ethanol production (DDGS(ethanol)) and DDGS from beverage production (DDGS(beverage)). In Exp. 1, five samples of DDGS(ethanol) were sourced from Minnesota (MN1, MN2), Illinois (IL1, IL2), and from Kentucky (KY). In Exp. 2, six samples of DDGS(ethanol), 1 sample of DDG, and 1 sample of DDGS(beverage) were used to compare values for apparent ileal digestibility and standardized ileal digestibility (SID) of AA between DDGS(ethanol) and DDGS(beverage) and between DDG and DDGS(ethanol). Results of Exp. 1 showed that the SID of Lys in DDGS from MN2 (72.8%) was greater (P < 0.01) than in DDGS from MN1 (66.8%), IL1 (66.8%), and KY (65.8%) but not different from IL2 (70.1%). Except for Leu and Glu, no differences in SID for any of the other AA were observed among the 5 sources of DDGS. In Exp. 2, the SID for Lys in DDGS(beverage) was greater (P < 0.01) than in DDGS(ethanol) (69.3 vs. 64.8%), but for CP and all other AA except His, no differences between the 2 types of DDGS were observed. The SID for most AA in DDG were greater (P < 0.05) than in DDGS(ethanol), which suggests that the AA in the solubles that are added to DDGS may be less digestible than the AA in DDG. In conclusion, results of these experiments confirm that the digestibility of Lys is more variable among sources of DDGS than the digestibility of other AA. However, the SID of AA among DDGS sources within a region can vary as much as among DDGS sources from different regions, and AA in DDGS(beverage) may be as digestible as AA in DDGS(ethanol). The digestibility of AA in DDG is greater than in DDGS, which indicates that AA in the solubles have a lower digestibility than AA in DDG.     

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.     

Relative ileal amino acid flows and microbial counts in intestinal effluents of Goettingen Minipigs and Saddleback pigs are not different

We explored the suitability of Goettingen Minipigs as models to measure ileal AA digestibility and evaluate dietary proteins for conventional pigs. Further, a potential for secondary ileal microbial colonization 5 mo after establishing end-to-end ileorectal anastomosis was investigated. Goettingen Minipigs (BW 18 kg) and Saddleback pigs (BW 27 kg) fitted with end-to-end ileorectal anastomosis were fed six diets based on barley and oilseed meals and three diets based on wheat and milk powder differing in total and ileal digestible lysine. Apparent ileal digestibilities of CP (N x 6.25) and of 20 AA were determined. No differences (P = 0.062 to 0.982) were found in AA apparent ileal digestibilities between breeds. Therefore, Minipigs are a reasonable model to estimate apparent ileal digestibility of AA for evaluation of dietary proteins. However, the apparent ileal digestibility of CP (P = 0.048) was higher in Minipigs than in Saddleback pigs (barley and oilseed meals-based diets 70% vs. 66%; wheat and milk powder-based diets 80% vs. 77%), which is probably due to a smaller contribution of non-AA-nitrogen in the ileal effluent of Goettingen Minipigs. For lysine, the apparent ileal digestibilities (means of both breeds) ranged from 78 to 85% in wheat and milk powder-based, and 70 to 78% in barley and oilseed-based diets. Experimentally derived concentrations of ileally digestible lysine confirmed the values predicted from a published table. Microbial counts were not affected by breed as shown for lactobacilli, with 9.1+/-0.2 and 9.1+/-0.2 (P = 0.977), enterococci with 4.8+/-0.3 and 5.6+/-0.4 (P = 0.162), and yeasts with 4.6+/-0.3 and 4.6+/-0.4 (P = 0.906) log cfu/g effluent for Goettingen Minipigs and Saddleback pigs, respectively. The counts did not change over 5 mo, suggesting that no secondary microbial colonization occurred in pigs with end-to-end ileorectal anastomosis.     

Amino acid digestibility of corn distillers dried grains with solubles, liquid condensed solubles, pulse dried thin stillage, and syrup balls fed to growing pigs

Distillers dried grains with solubles (DDGS) has low and variable AA digestibility. The variability is often attributed to damage during the heating process, and it has been suggested that the damage happens to the soluble components of DDGS such as reducing sugars. Combining solubles and grains sometimes produces syrup balls (SB); their digestibility is unknown. The objective of this experiment was to identify potential sources of poor and variable AA digestibility in DDGS. Specifically, our objective was to determine whether the problems are associated with the solubles component or with SB. The ingredients evaluated were DDGS, intact SB, ground SB, liquid condensed solubles (LCS), and pulse dried thin stillage (PDTS) obtained from the same ethanol plant. The LCS is produced by evaporation of thin stillage. Each ingredient was used as the only source of AA in an experimental diet. In a duplicate 6 × 6 Latin square design with 7-d adaptation and collection periods, the 6 treatments consisted of an N-free diet and the 5 test ingredients. Pigs had 5 d of adaptation to each diet, and on d 6 and 7 ileal digesta were collected from an ileal cannula for 8 h each day. Both SB treatments had apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of AA that were similar or greater (P < 0.05) than those of DDGS. The AID and SID values of Lys and a few other AA were similar in LCS (SID Lys: 63.1%) and DDGS (SID Lys: 61.5%), but the digestibility values of most AA in LCS were less than in DDGS (P < 0.05). The low digestibility of AA in LCS was most pronounced for Met (SID: LCS, 41.9% vs. DDGS, 82.8%). The LCS had less (P < 0.05) AID and SID of CP (SID: 67.8%) than intact SB (SID: 85.2%) and ground SB (SID: 85.9%) as well as all AA. The PDTS generally had the least AID and SID and had less (P < 0.05) CP (SID: 55.3%) and several AA, including Lys, compared with LCS. In conclusion, the presence of SB does not decrease AA digestibility of DDGS, and the LCS evaluated has less indispensible AA digestibility than DDGS. The LCS has low digestibility of AA that seems to not be caused by heat damage.     

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 and energy digestibility in ten samples of distillers dried grain with solubles fed to growing pigs

The objective of this experiment was to measure the digestibilities of energy, CP, and AA in 10 samples of corn distillers dried grain with solubles (DDGS) and in corn fed to growing pigs. Twelve growing barrows (initial BW: 34.0 +/- 1.41 kg) were allotted to an 8 x 12 Youden square design with 8 periods and 12 animals. Ten of 12 diets were based on the 10 DDGS samples (66.7%), 1 diet was based on corn (97%), and the last diet was a N-free diet based on cornstarch and sucrose. Chromic oxide (0.3%) was included in all diets as an inert marker. Pigs were provided their respective diets at a level of 3 times their estimated energy requirement for maintenance. The apparent (AID) and standardized (SID) ileal digestibilities for CP and AA were measured in the 10 samples of DDGS and in corn using the direct procedure, but the apparent total tract digestibilities for DM and GE were estimated using the difference procedure. The concentration of DE in each sample of DDGS and in corn was also calculated. The results of the experiment indicated variation among the different sources of DDGS in AID and SID for Lys, which ranged from 35.0 to 55.9% and 43.9 to 63.0%, respectively. For Met, the SID varied between 73.9 and 84.7%. However, the variability among samples in the SID for CP, and for the indispensable AA other than Lys and Met, was relatively low and ranged between 6 and 8 percentage units (i.e., from 64.0 to 70.6%, 74.1 to 80.1%, and 67.4 to 75.3% for Thr, Trp, and Ile, respectively). The SID for Trp in corn (72.8%) was lower (P < 0.05) than in DDGS, but for the remaining indispensable AA, except Arg, the SID for corn were greater (P < 0.01) than for DDGS. The DE concentration in the 10 samples of DDGS varied (P < 0.001) from 3,382 to 3,811 kcal of DE per kg of DM. For corn, the DE was 3,845 kcal per kg of DM. It is concluded that the AID and SID for Lys vary among samples of DDGS, but for most other AA the AID and SID are relatively similar and vary only 6 to 8 percentage units among different samples. Future work should focus on identifying the reasons for the variation in the digestibility of Lys to avoid processing procedures that are detrimental to Lys digestibility.     

Evaluation of the homoarginine technique for measuring true ileal amino acid digestibilities in pigs fed a barley-canola meal-based diet

The homoarginine technique has been suggested as a means to determine true ileal amino acid digestibilities in nonruminant animals fed protein-containing diets. Conditions for guanidinating lysine to homoarginine in barley and canola meal and the effect of this process on nutrient composition and ileal digestibilities in the resulting material were investigated. Conditions tested were methylisourea concentration (0.4, 0.5, or 0.6 M) and reaction time (4 or 6 d) at pH 10.5. Using 0.4 methylisourea M solution for 4 or 6 d gave guanidination rates of 72.5 and 78.5% for barley and 72.3 and 75.2% for canola meal, respectively. Using 0.5 M gave 88.0 and 84.6% guanidination rates in barley and canola meal, respectively, after a 6-d reaction time. Under these conditions, guanidination did not change the nutrient composition of barley (P > 0.10), whereas it increased CP (38.4 vs 49.0%), crude fiber (10.2 vs 16.0%), acid detergent fiber (30.0 vs 43.4%) and neutral detergent fiber (29.8 vs 49.4%) levels in canola meal (P < 0.05). Four 33.6-kg barrows fitted with a simple T-cannula at the terminal ileum were fed a 16% CP unguanidinated barley and canola meal-based diet for four consecutive 14-d periods. Ileal digesta were collected continuously for 24 h on d 12 and 14 to determine apparent nutrient digestibilities. On the morning of d 14, pigs were fed a diet in which half of the barley and canola meal was replaced with guanidinated material for determining true ileal amino acid digestibilities. Digesta samples were pooled by pig and by 24-h period to give 16 observations per diet. Apparent ileal digestibilities of DM, CP, and AA in the unguanidinated and guanidinated barley-canola meal diet were similar (P > 0.10) despite the changes observed in canola meal. Apparent ileal lysine digestibility was 73.9 and 74.5% in the unguanidinated and guanidinated diet, respectively. The true ileal lysine digestibility was 88.1%. The present results show that guanidination does not interfere with digestion and further support the use of the homoarginine method for determining true ileal amino acid digestibilities in pigs fed practical diets. A methylisourea solution of 0.5 M and a 6-d reaction time are recommended for converting lysine to homoarginine in barley and canola meal.     

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.     

Apparent digestibility of nitrogen and amino acids in protein feedstuffs by growing pigs

Eight digestion trials were conducted with pigs fitted with ileal T-cannulas to determine the apparent digestibilities of N and amino acids in common protein feedstuffs. Trial-to-trial variation was minimal as determined by the variation in digestibilities for soybean meal, which was evaluated in each trial. Apparent digestibilities varied widely; ileal N digestibility ranged from 88 to 63%, and ileal lysine digestibility ranged from 93 to 40%. In general, ring-dried blood meal, corn gluten meal, Menhaden fish meal, poultry-by-product meal and extruded whole soybeans were the most digestible, followed by canola meal, sunflower meal, peanut meal and meat and bone meal. Cottonseed meal and feather meal were the least digestible. Mean values for each feedstuff agree well with published data. Variation in digestibilities among samples of the same feedstuff was greater for the meat and bone meals. Regression of ileal essential amino acid digestibilities on ileal and fecal N digestibility indicated that amino acid digestibilities can be predicted more precisely from ileal N digestibility than from fecal N digestibility. However, neither ileal nor fecal N digestibility could be used with a high degree of certainty to predict ileal amino acid digestibilities.     

Amino acid digestibility in low-fat distillers dried grains with solubles fed to growing pigs

The objective of this experiment was to determine the standardized ileal digestibility (SID) of amino acids (AA) in 3 sources of distillers dried grains with solubles (DDGS) with different concentrations of fat. Twelve growing barrows (initial body weight: 76.1 ± 6.2 kg) were randomly allotted to a replicated 6 × 4 Youden square design with 6 diets and 4 periods. The fat content of the 3 sources of DDGS were 11.5, 7.5, and 6.9% respectively. Diets contained 60% DDGS and fat concentration of the diets were 7.5, 5.2, and 5.2%, respectively. Two additional diets containing the 2 sources of DDGS with 7.5 and 6.9% fat were also formulated, and corn oil was added to these diets to increase the concentration of fat in the diets to levels that were calculated to be similar to the diet containing conventional DDGS with 11.5% fat. A N-free diet was also formulated to calculate endogenous losses of crude protein (CP) and AA from the pigs. Pigs were fed experimental diets during four 7-d periods. The first 5 d of each period were an adaptation period and ileal digesta were collected on d 6 and 7 of each period. The apparent ileal digestibililty (AID) and SID of CP and all indispensable AA, except AID Pro and SID of Trp, were greater (P < 0.01) in conventional DDGS than in the 2 sources of DDGS with reduced fat. Adding oil to the diets containing the 2 sources of DDGS with reduced fat did not consistently increase SID of AA. In conclusion, conventional DDGS has greater SID values for most AA compared with DDGS that contains less fat and inclusion of additional oil to diets containing low-fat DDGS does not increase AID or SID of AA. The lower AA digestibility in low-fat DDGS could not be overcome by the inclusion of additional fat to the diets.     

Evaluation of mobile nylon bag technique for determining apparent ileal digestibilities of protein and amino acids in growing pigs

The mobile nylon bag technique (MNBT) may offer a simple, rapid means for assessing ileal AA digestibility of pig feed ingredients. In the present study, the effects of washing bags recovered from digesta, the amount and fineness of feeds, and feed trypsin inhibitor activity on apparent ileal digestibilities (AID) of CP and AA were determined with the MNBT. Twenty-four ileorectal anastomosed pigs (Yorkshire x Chinese Black barrows, 30 kg initial BW), of which 12 were fitted with duodenal T-cannulas, were used. Not washing the bags recovered from ileal digesta resulted in a reduction (P < 0.05) in apparent ileal digestibilities of CP and AA determined by MNBT. Washing the bags for more than 4 min overestimated (P < 0.05) the apparent ileal digestibilities of CP and AA compared with those determined with the anastomosed pigs. Sample size and fineness of grinding also affected (P < 0.05) apparent ileal digestibilities of CP determined by MNBT. The apparent ileal digestibilities of CP determined by MNBT were reduced (P < 0.05) when sample size exceeded 0.75 g and when feed was ground through screens with a mesh size of more than 1.0 mm. The closest agreement between results obtained by MNBT and a conventional ileal digestibility assay occurred when 0.75 g of feed ground through a 1.0-mm mesh screen was used per bag and bags were washed for 2 min after retrieval from digesta. Further studies are warranted to investigate the use of the mobile nylon bag technique for predicting the ileal digestibilty of AA for feeds containing antinutritional factors.     

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.     

Digestibility of phosphorus in growing pigs as influenced by source and concentration of dietary phosphorus and collection site

The current study examined the influence of source and concentration of dietary phosphorus (P) on the apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of P in growing pigs. Eighteen cannulated barrows (25 ± 5 kg) were allotted to a triplicate 6 × 3 incomplete Latin square design with six diets and three periods. The diets comprised of soybean meal (SBM) or distillers' dried grain with solubles ( DDGS) as sole sources of dietary P, and three concentrations of P (2.0, 2.5 or 3.0 g/kg) in a 2 × 3 factorial arrangement. The AID and ATTD of P were not different (p = 0.37) in all diets. Apparent digestibility of P was affected (p < 0.01) by source and concentration of P. There was no interaction between source and concentration of dietary P on the apparent digestibility of P. Determined by regression analysis, the true ileal digestibility of P was 58.3% or 57.6%, and true total tract digestibility of P was 56.0% or 62.6%, for SBM or DDGS, respectively. The regression-derived ileal endogenous P loss (EPL) was 0.61 or 0.13 g/kg DM intake, and total tract EPL was 0.53 or 0.35 g/kg DM intake, for SBM or DDGS, respectively. In conclusion, the study demonstrated that both the source and concentration of dietary P affect the digestibility of P in growing pigs.     

Digestibility of amino acids in corn, corn coproducts, and bakery meal fed to growing pigs

The objectives of this experiment were to determine the apparent ileal digestibility and the standardized ileal digestibility (SID) of CP and AA in bakery meal, corn gluten meal, corn gluten feed, corn germ meal, and hominy feed and to compare these values with the apparent ileal digestibility and SID of CP and AA in corn and distillers dried grains with solubles (DDGS). Eight growing barrows (initial BW: 82.5 ± 5.5 kg) were randomly allotted to an 8 × 8 Latin square design with 8 diets and 8 periods. Diets contained corn, DDGS, bakery meal, corn gluten meal, corn gluten feed, corn germ meal, or hominy feed as the sole source of protein and AA. An N-free diet was used to measure basal endogenous losses of AA and protein. Pigs were fed experimental diets for eight 7-d periods, with ileal digesta being collected on d 6 and 7 of each period. Results indicated that the SID of Lys in corn gluten meal (78.7%) was greater (P < 0.01) than in DDGS, bakery meal, corn germ meal, and hominy feed (46.0, 48.4, 68.4, and 58.8%, respectively). The SID of all indispensable AA except Arg, Leu, and Met in bakery meal were not different from those in DDGS. The SID of Arg, His, Leu, and Met in corn gluten feed were less (P < 0.01) than in corn, but the SID of all other indispensable AA in corn gluten feed were not different from those in corn. However, for most indispensable AA, the SID in corn gluten feed was not different from the SID in DDGS. The SID of all indispensable AA in corn germ meal, except Arg, His, Leu, and Met, were not different from the SID in corn. Likewise, the SID of all indispensable AA in corn germ meal, except Arg and Leu, were not different from those in DDGS. The SID of Ile, Met, Phe, and Val in hominy feed were less (P < 0.01) than in corn, but the SID of the remaining indispensable AA in hominy feed were not different from the SID of indispensable AA in corn. All indispensable AA in hominy feed also had SID values that were not different from the SID values of AA in DDGS, except for Arg and Lys, which had greater (P < 0.01) SID than in DDGS. In conclusion, bakery meal had SID values of most AA that were less than in corn, but corn gluten meal had SID values for most AA that were greater than the SID of AA in corn, bakery meal, and corn coproducts.     

Amino acid digestibilities in different samples of wheat shorts for growing pigs.

An experiment was carried out to investigate the variability in apparent ileal amino acid (AA) digestibilities in simulated samples of wheat shorts consisting of different proportions of wheat bran (WB), wheat shorts (WS), and wheat flour (WF), hereafter referred to as wheat fractions. The proportions of WS, WB, and WF and the NDF content (DM basis) of the wheat fractions were as follows: A, 70% WS, 30% WB, and 42.3% NDF; B, 85% WS, 15% WB, and 41.8% NDF; C, 100% WS and 41.3% NDF; D, 85% WS, 15% WF, and 35.2% NDF; and E, 70% WS, 30% WF, and 29.5% NDF. Six barrows, average initial BW of 37.2 kg, fitted with a simple T-cannula at the distal ileum, were fed one of six experimental diets according to a 6 x 6 Latin square design. Six diets were formulated to contain 17% CP (as-fed basis). Diets A, B, C, D, and E contained 17.53% soybean meal (SBM), which contributed 50% of the CP in these diets. The wheat fractions contributed the remaining 50% of the CP in these diets. Diet F contained 35.05% SBM, which was the sole source of dietary CP. Chromic oxide was used as the digestibility marker. During the first experimental period, the daily dietary allowance was provided at a rate of 5% (wt/wt) of the average BW. Thereafter, the daily dietary allowance was increased by 100 g at each successive period. Each experimental period comprised 12 d. Following a 7-d adaptation period, feces were collected for 48 h and ileal digesta for a total of 24 h. The apparent ileal digestibilities of AA in the wheat fractions were calculated using the difference method. The digestibilities were usually lowest in the wheat fractions containing WB and highest in those containing no WB. The average of the digestibilities of the indispensable AA was 63.5% for wheat fraction A, which contained 30% WB, and 71.9% for wheat fraction C, which did not contain WB. There were no differences (P > .05) in lysine digestibilities among the wheat fractions, which ranged from 54.7 to 64.1%. Of the indispensable AA, with the exception of arginine, lysine, and methionine, the apparent ileal digestibility values of AA were negatively correlated (P < .05) with the NDF content in the wheat fractions.     

加州鲈对15种饲料原料体外消化率的测定

采用"胃-肠"两步法测定了加州鲈(Micropterus salmoides)对15种饲料原料的体外消化率,并与银鲈(Bidyanus bidyanus)体内消化率数据进行了比较。结果表明:加州鲈对秘鲁鱼粉、喷干血粉、豆粕、花生麸、玉米蛋白粉、酵母膏、破壁酵母7种原料的体外消化率较高(干物质>45%,蛋白质>71%),对玉米、DDGS消化率较低(干物质<17%,蛋白质<61%),且大部分原料的体内、外消化率结果具有极显著的相关性(P<0.01)。体外消化率的结果可为加州鲈饲料原料的选择提供参考依据。     

Evaluation of a high-protein DDGS product in broiler chickens: performance,nitrogen-corrected apparent metabolisable energy,and standardised ileal amino acid digestibility

ABSTRACT

1. New production processes and additional uses for corn co-products have increased the availability of distiller’s dried grains with solubles (DDGS) with varying energy and amino acid digestibility, for use in poultry feed. The objective of this study was to determine the performance, N-corrected metabolisable energy (AME_n), and amino acid (AA) digestibility of a 34% CP (as fed) high-protein DDGS (HP-DDGS) included in poultry diets for Cobb 500 broiler chickens.

2. A total of 832 Cobb 500 broilers were randomly assigned to four dietary treatments containing 5% conventional DDGS (CV-DDGS) as a control or 10%, 15% and 20% HP-DDGS and fed for 42 d. After the performance trial, 240 birds from the original 832 were selected for a concurrent AME_n and AA digestibility experiment consisting of two AME_n diets and two AA diets.

3. Birds fed diets containing 15% and 20% HP DDGS gained less weight than birds fed the CV-DDGS (P < 0.05) but did not differ in feed intake (FI), and therefore had a less efficient FCR than the control (P < 0.05). The AME_n of HP-DDGS was determined to be 11.4 MJ/kg. The standardised ileal amino acid digestibility (SIAAD) of the essential amino acids Lys and Met were determined to be 80.9% and 88.6%, respectively.

4. HP-DDGS can be included in broiler diets up to 10% without any negative impact on performance or requiring supplemental Lys and Arg. The results from the AA digestibility study indicated that HP-DDGS could be a good source of digestible Lys.     

Effects of xylanase supplementation on the apparent digestibility and digestible content of energy, amino acids, phosphorus, and calcium in wheat and wheat by-products from dry milling fed to grower pigs

Wheat by-products are feedstuffs that vary in nutritional value, partly because of arabinoxylans that limit nutrient digestibility. Millrun is a byproduct from dry milling wheat into flour and contains varying amounts of the bran, middlings, screening, and shorts fractions. The digestible nutrient content of mill-run is not well known. Effects of xylanase supplementation (0 or 4,000 units/kg of diet) on energy, AA, P, and Ca digestibilities were studied in a wheat control diet and 5 diets containing 30% of a by-product (mill-run, middlings, shorts, screening, or bran) in a 2 x 6 factorial arrangement of treatments. The wheat control diet was formulated to contain 3.34 Mcal of DE/kg and 3.0 g of standardized ileal digestible Lys/Mcal of DE. Diets contained 0.4% chromic oxide. Each of 12 ileal-cannulated pigs (32.5 +/- 2.5 kg) was fed 6 or 7 of 12 diets at 3 times the DE requirement for maintenance in successive 10-d periods for 6 or 7 observations per diet. Feces and ileal digesta were each collected for 2 d. Xylanase tended to increase (P < 0.10) ileal energy digestibility by 2.2 percentage units and the DE content by 0.10 Mcal/kg of DM and increased (P < 0.05) ileal DM digestibility by 2.8 percentage units; a diet x xylanase interaction was not observed. Xylanase increased (P < 0.05) total tract energy and DM digestibilities and the DE content. A diet x xylanase interaction was observed; xylanase increased (P < 0.05) total tract energy digestibility of the millrun diet from 72.1 to 78.9%, DE content from 3.19 to 3.51 Mcal/kg of DM, and DM digestibility from 71.5 to 78.6%. Diet affected (P < 0.05) and xylanase improved (P < 0.05) digestibility and digestible contents of some AA in diets and by-products, including Lys, Thr, and Val. Xylanase increased (P < 0.05) Lys digestibility by 13.8, 5.0, 5.2, 6.0, and 14.1 percentage units in millrun, middlings, shorts, screening, and bran, respectively. Diet affected (P < 0.01) total tract P and Ca digestibilities. Xylanase increased (P < 0.05) digestible P and Ca contents. In summary, nutrient digestibility varies among wheat by-products. Millrun contained 2.65 Mcal of DE/kg of DM, which xylanase increased to 3.56 Mcal of DE/kg of DM. Xylanase improved nutrient digestibility and DE content in wheat by-products; and the extent of improvement depended on the by-product. Xylanase supplementation may maximize opportunities to include wheat byproducts in swine diets and ameliorate reductions in nutrient digestibility that may be associated with arabinoxylans.     

Apparent digestibility of amino acids, gross energy and starch in corn, sorghum, wheat, barley, oat groats and wheat middlings for growing pigs

Apparent nutrient digestibilities of yellow-dent corn, low-tannin sorghum, hard red winter wheat, barley, oat groats and wheat middlings were determined near the end of the small intestine and over the total digestive tract of growing pigs. Gross energy digestibilities for corn, sorghum and oat groats were similar; wheat had a slightly lower (P less than .05) digestibility, followed by barley (P less than .05), with wheat middlings being the least (P less than .05) digestible. About 7% of the gross energy in corn, sorghum, wheat and oat groats was digested in the large intestine, compared with 11% for barley and 17% for wheat middlings. The starch in all products was essentially 100% digestible by the end of the small intestine. Ileal amino acid digestibilities tended to be highest for wheat and oat groats, followed by corn, sorghum, barley and wheat middlings. The range in ileal digestibilities was 73.8 (sorghum) to 84.2% (wheat) for lysine, 69.6 (corn) to 81.4% (wheat) for tryptophan and 63.4 (wheat middlings) to 77.9% (oat groats) for threonine. Amino acid digestibilities determined over the total tract were generally higher than ileal digestibilities; however, values for lysine, methionine and phenylalanine were generally lower, indicating a net synthesis of these amino acids in the large intestine.