Standardized Ileal Digestibility Of AA Research Articles

Feeding reduced crude protein diets with crystalline amino acids supplementation reduce air gas emissions from housing1

The objective of this study was to test the hypothesis that reducing dietary CP by 1.5% and supplementing crystalline AA (CAA) to meet the standardized ileal digestible (SID) AA requirements for growing and finishing pigs decreases air emissions of ammonia (NH), nitrous oxide (NO), and carbon dioxide (CO) compared with an industry standard diet, without reducing growth performance. Seventy-two pigs were allocated to 12 rooms (6 pigs per room) and 2 diets (6 rooms per diet) formulated according to a 5-phase feeding program across the grow-finish period (107 d total). The diets consisted of a standard diet containing 18.5 to 12.2% CP or a reduced CP diet containing 17.5 to 11.0% CP + CAA over the course of the 5-phase feeding program. Gases (NH, NO, hydrogen sulfide, methane, nonmethane total hydrocarbon, and CO) and ventilation rates were measured continuously from the rooms. Compared with standard diet, ADG and feed conversion of pigs fed reduced CP + CAA diets did not differ (2.7 kg gain/d and 0.37 kg gain/kg feed, respectively). Compared with standard diet, feeding reduced CP + CAA diets decreased ( < 0.01) NH emissions by 46% over the 107-d period (5.4 and 2.9 g · pig · d, respectively). Change in NH emissions for each percentage unit reduction in dietary CP concentration corresponded with 47.9, 53.2, 26.8, 26.5, and 51.6% during Phases 1 through 5, respectively. Emissions of other gases did not differ between diets. Feeding reduced CP diets formulated based on SID AA requirements for grow-finisher swine is effective in reducing NH emissions from housing compared with recent industry formulations and does not impact growth performances.

Effects of protein concentration and heat treatment on concentration of digestible and metabolizable energy and on amino acid digestibility in four sources of canola meal fed to growing pigs.

Two experiments were conducted to determine DE and ME and the apparent ileal digestibility (AID) and the standardized ileal digestibility (SID) of CP and AA in 4 sources of canola meal (high-protein [CM-HP], high-temperature-processed [CM-HT], low-temperature-processed [CM-LT], and conventional [CM-CV] canola meal) and in conventional soybean meal (SBM) fed to growing pigs. In Exp. 1, 48 growing barrows (initial BW: 39.7 ± 1.58 kg) were individually housed in metabolism cages and randomly assigned to 6 treatments in a randomized complete block design with 2 blocks of 24 pigs and 8 replicate pigs per treatment. The 6 diets included a corn-based basal diet and 5 diets that were formulated by mixing corn and 1 of the sources of canola meal (39.0% inclusion) or SBM (28.5% inclusion). Feces and urine were collected for 5 d following a 5-d adaptation period. The DE and ME in each source of canola meal and in SBM were calculated using the difference procedure. The DE and ME in the 4 sources of canola meal were less (P < 0.05) than in corn and SBM (DE: 2,854, 2,680, 2,892, and 2,883 vs. 3,324 and 3,784 kcal/kg, respectively; ME: 2,540, 2,251, 2,681, and 2,637 vs. 3,213 and 3,523 kcal/kg, respectively). No differences in the concentrations of DE and ME were observed among the 4 sources of canola meal. In Exp. 2, 12 growing barrows (initial BW: 34.0 ± 1.41 kg) that had a T-cannula installed in the distal ileum were randomly allotted to a repeated 6 × 6 Latin square design with 6 diets and 6 periods in each square. Five diets that contained 35% SBM or 45% of 1 of the 4 sources of canola meal as the sole source of CP and AA were formulated, and a N-free diet was also used. Each period lasted 7 d and ileal digesta were collected on d 6 and 7 of each period. The AID and SID of CP and all AA in SBM were greater (P < 0.05) than in the 4 sources of canola meal. Compared with CM-CV, CM-HP had greater (P < 0.05) AID of Ile, Lys, Asp, Cys, and Pro and greater (P < 0.05) SID of Lys and Cys. However, no differences between CM-HT and CM-LT were observed. In conclusion, regardless of the concentration of CP and the processing used, canola meal provides less DE and ME to pigs than corn and SBM, and the SID of AA in canola meal is less than in SBM. The processing temperature used in this experiment did not affect DE and ME or SID of AA in canola meal. The SID of Lys and Cys was greater in CM-HP than in CM-CV.

Evaluation of standardized ileal digestible valine:lysine, total lysine:crude protein, and replacing fish meal, meat and bone meal, and poultry byproduct meal with crystalline amino acids on growth performance of nursery pigs from seven to twelve kilograms

Five experiments were conducted to evaluate replacing fish meal, meat and bone meal, and poultry byproduct meal with crystalline AA for 7- to 12-kg pigs. In all experiments, pigs (PIC TR4 × 1050) were fed a common diet for 3 d postweaning, treatment diets for 14 d (d 0 to 14), and, again, a common diet for 14 d (d 14 to 28). Treatment diets were corn-soybean meal based and formulated to contain 1.30% standardized ileal digestible (SID) Lys. Experiment 1 evaluated replacing dietary fish meal with crystalline AA. For the 6 treatments, crystalline Lys, Met, Thr, Trp, Ile, Val, Gln, and Gly all increased to maintain minimum AA ratios as fish meal decreased (4.50, 3.60, 2.70, 1.80, and 0.90 to 0.00%). There was no difference in ADG, ADFI, or G:F among treatments, validating a low-CP, AA-fortified diet for subsequent experiments. Experiment 2 evaluated deleting crystalline AA from a low-CP, AA-fortified diet with 6 treatments: 1) a positive control similar to the diet validated in Exp. 1, 2) positive control with l-Ile deleted, 3) positive control with l-Trp deleted, 4) positive control with l-Val deleted, 5) positive control with l-Gln and l-Gly deleted, and 6) positive control with l-Ile, l-Trp, l-Val, l-Gln, and l-Gly deleted (NC). Pigs fed the positive control or Ile deleted diet had improved (P < 0.05) ADG and ADFI during d 0 to 14 compared with pigs fed diets with l-Trp or l-Val deleted or NC. Experiment 3 evaluated 6 treatments with total Lys:CP of 6.79, 6.92, 7.06, 7.20, 7.35, and 7.51%. Fish meal was adjusted as a source of dispensable N to achieve the target Lys:CP. There were no differences in growth performance among pigs fed different Lys:CP diets. Experiment 4 evaluated increasing SID Val:Lys with Val at 57.4, 59.9, 62.3, 64.7, 67.2, and 69.6% of Lys. Average daily gain and ADFI increased (quadratic, P < 0.01) and G:F improved (linear, P = 0.02) during d 0 to 14 as Val:Lys increased from 57.4 to 64.7%. Experiment 5 was a 2 × 3 factorial arrangement of treatments with main effects of low or high level of crystalline AA and 3 animal protein sources (fish meal, meat and bone meal, or poultry byproduct meal). Low- and high-crystalline AA diets contained 4.5 or 1% fish meal, 6 or 1.2% meat and bone meal, and 6 or 1% poultry byproduct meal, respectively. No AA × protein source interactions were observed. From d 0 to 14, no differences in growth performance among protein sources was found, whereas increasing crystalline AA improved (P = 0.04) ADG. In conclusion, crystalline AA can replace fish meal, meat and bone meal, and poultry byproduct meal when balanced for SID AA ratios of Met and Cys:Lys (58%), Thr:Lys (62%), Trp:Lys (16.5%), Val:Lys (65%), and Ile:Lys (52%).

Standardized ileal digestibility of amino acids in alfalfa meal, sugar beet pulp, and wheat bran compared to wheat and protein ingredients for growing pigs1

A total of 11 (8 + 3 for replacement) barrows with an initial BW of 23 kg and fitted with a simple T-cannula at the distal ileum were used in 2 consecutive experiments (Exp. 1 and Exp. 2) to determine the standardized ileal digestibility (SID) of AA in 7 assay feed ingredients according to 2 consecutive duplicated 4 × 4 Latin square designs. In Exp. 1, 3 corn starch-based assay diets were formulated to contain 170 g CP/kg (as-fed basis) from either soybean meal (SBM), canola meal (CM), or meat-and-bone meal (MBM) and 1 assay diet that contained 136 g CP/kg (as-fed basis) from wheat as commonly used feed ingredients for pigs. In Exp. 2, the pigs were fed 4 assay diets formulated to contain 170 g CP/kg (as-fed basis) from either the same SBM as in Exp. 1 or a combination of this SBM and alfalfa meal (AM), sugar beet pulp (SB), or wheat bran (WB) to compare the SID of AA in these feed ingredients with those used in Exp. 1. The SID of AA in CM was lower compared to SBM (P < 0.05) with intermediate values for MBM and wheat. Among fiber rich feed ingredients, SID values were lower in SB compared to WB (P < 0.05) with intermediate values for AM. In AM, SID values ranged between 29 and 45% for Lys, Cys, Thr, and Phe and between 51 and 71% for Arg, His, Ile, Leu, Met, and Val. In SB, SID values ranged between -21 and 46% for Cys, Thr, Phe, and Val and between 51 and 61% for Arg, His, Ile, Leu, Lys, and Met. In WB, SID values were between 55 and 64% for Lys, Cys, Phe, Thr, and Val and between 68 and 80% for Arg, His, Ile, Leu, and Met. The SID values in WB, SB, and AM provided in the present study may improve diet formulation when these feed ingredients are used in diet formulation for pigs.

Digestibility by growing pigs of amino acids in heat-damaged sunflower meal and cottonseed meal1

Two experiments were conducted to determine the effects of heat damage, achieved by autoclaving, on the nutritional composition and on the standardized ileal digestibility (SID) of AA in sunflower meal (SFM) and cottonseed meal (CSM) fed to growing pigs. The second objective was to establish a relationship between the concentration of SID AA in SFM and CSM and the concentration of fiber components, reducing sugars, and AA. In Exp. 1, 10 growing pigs (initial BW: 23.1 ± 1.3 kg) were surgically equipped with a T-cannula in the distal ileum and allotted to a replicated 5 × 5 Latin square design with 5 diets and 5 periods in each square. A common source of SFM was separated into 4 batches that were either not autoclaved or autoclaved at 130°C for 20, 40, or 60 min. Four diets (approximately 14.5% CP) that contained each of the 4 batches of SFM were formulated, and SFM was the only source of CP and AA in the diets. A N-free diet that was used to determine the basal endogenous losses of CP and AA from pigs was also formulated. Each period consisted of 5 d of adaptation to the diets followed by 2 d of ileal digesta collection. The SID of Lys in SFM was reduced (linear, P < 0.05) from 83.2% in nonautoclaved SFM to 63.5% in SFM autoclaved for 60 min at 130°C. The concentrations of total Lys and reducing sugars in SFM may be used as predictors (R(2) = 0.85) of the concentration of SID Lys in SFM. In Exp. 2, 10 growing pigs (initial BW: 35.0 ± 1.5 kg) were surgically equipped with a T-cannula in the distal ileum and allotted to a replicated 5 × 5 Latin square design with 5 diets and 5 periods in each square. A source of CSM was separated into 4 batches that were either not autoclaved or autoclaved at 130°C for 15, 35, or 60 min. Four diets (approximately 13.4% CP) containing CSM as the only source of CP and AA were formulated. A N-free diet was also formulated and used as described for Exp. 1. The SID of Lys in nonautoclaved CSM (66.2%) was greater (P < 0.05) than in autoclaved (60 min at 130°C) CSM (54.1%). The equation (R(2) = 0.68) that best predicted the concentration of SID Lys in CSM included the concentration of ADIN. In conclusion, heat damage reduces the SID of AA in SFM and CSM. For SFM, the concentration of SID Lys may be predicted from the concentrations of total Lys and reducing sugars. The concentration of ADIN may be used to predict the concentration of SID Lys in CSM.

Validating a dietary approach to determine amino acid:lysine ratios for pigs (2014)

Standardized ileal digestible (SID) amino acid:lysine (AA:Lys) ratio experiments are commonly conducted to estimate the AA requirement of pigs relative to lysine (Lys) and allow for accurate diet formulation. The objective of the studies herein was to validate a dietary approach to determine the optimal SID AA:Lys ratio for pigs using tryptophan (Trp) as a model. Four 21-d experiments were conducted in which pigs (337 × 1050; PIC) were fed corn-soybean meal–based diets with 30% corn dried distillers grains with solubles (DDGS). A total of 1,188, 1,232, 1,204, and 1,183 pigs with initial BW of 28.5 ± 0.4, 50.1 ± 1.3, 127.0 ± 2.5, and 192.5 ± 2.6 lb were used in experiments 1, 2, 3, and 4, respectively. Each experiment had 11 pens per treatment with 24 to 28 pigs per pen. In Experiment 1, each pen housed the same number of barrows and gilts, whereas in Experiments 2 to 4 only gilts were used. Dietary treatments were: (1) High CP, High Lys, and High Trp:Lys ratio (HHH); (2) Low CP, High Lys, and High Trp:Lys ratio (LHH); (3) Low CP, Low Lys, and High Trp:Lys ratio (LLH); and (4) Low CP, Low Lys, and Low Trp:Lys ratio (LLL). The SID Trp concentrations used were 14.5 vs. 20% of Lys, CP was at least 3 percentage units different, and SID Lys levels were 0.01 percentage unit above the estimated requirement at the expected initial BW and 0.10 or 0.05 percentage units below requirement at the expected final BW of the Experiment 1 (nursery) and Experiments 2, 3, and 4 (finishing), respectively. In Experiment 1, decreasing CP (HHH vs. LHH) did not influence ADG but increased (P < 0.05) F/G. Decreasing Lys (LHH vs. LLH) and decreasing the SID Trp:Lys ratio (LLH vs. LLL) reduced (P < 0.05) ADG and increased (P < 0.05) F/G. In Experiment 2, decreasing CP (HHH vs. LHH) did not affect ADG but increased (P < 0.05) F/G. Decreasing Lys (LHH vs. LLH) and the SID Trp:Lys ratio (LLH vs. LLL) decreased (P < 0.05) ADG and increased (P < 0.05) F/G. In Experiment 3, decreasing CP (HHH vs. LHH) or Lys (LHH vs. LLH) did not influence ADG or F/G. Decreasing the SID Trp:Lys ratio (LLH vs. LLL) reduced (P < 0.05) ADG and increased (P < 0.05) F/G. In Experiment 4, decreasing CP (HHH vs. LHH) did not influence ADG but increased (P

Nutrient digestibility of lentil and regular- and low-oligosaccharide, micronized full-fat soybean fed to grower pigs1

A study was conducted to determine the standardized ileal digestibility (SID) of AA and calculate the NE value for regular-oligosaccharide, micronized full-fat soybean (R-MFFSB), low-oligosaccharide, micronized full-fat soybean (LO-MFFSB), lentil, and enzymatically hydrolyzed casein (EHC) for growing pigs. Six ileal-cannulated barrows (31.4 kg BW) were fed 6 diets in a 6 × 6 Latin square. Five diets were cornstarch based, containing either soybean meal (SBM), R-MFFSB, LO-MFFSB, or EHC as sole protein source or N free. The sixth diet contained lentil as sole protein and energy source. The SID of AA for diets was calculated using the N-free diet. Digestibility of AA in feedstuffs was determined by the direct method. Energy digestibility in SBM, R-MFFSB, and LO-MFFSB was determined by difference from the N-free diet whereas energy digestibility in lentil was determined by the direct method. On DM basis, SBM, R-MFFSB, LO-MFFSB, and lentil contained 52, 43, 43, and 27% CP, 8, 12, 14, and 16% NDF, and 1.8, 19, 21, and 1.6% ether extract, respectively. The SID of Lys for SBM was greater (P < 0.05) than that for R-MFFSB or LO-MFFSB (76 vs. 79 and 79%). The SID of other indispensable AA (except Trp) for SBM was also greater (P < 0.05) than that for R-MFFSB or LO-MFFSB. The R-MFFSB and LO-MFFSB were similar in SID of AA. The SID of Lys for lentil (81%) was lower (P < 0.05) than that for SBM with a similar trend for SID of other indispensable AA except for Met and Thr whose SID was similar to SBM. The SID of AA for EHC ranged from 98 to 112%. The SBM had a lower (P < 0.05) NE value than R-MFFSB or LO-MFFSB (2.63 vs. 2.95 and 3.00 Mcal/kg DM). Lentil and SBM were similar in NE value (2.60 vs. 2.63 Mcal/kg DM). In conclusion, R-MFFSB and LO-MFFSB were similar in energy and AA value for pigs. Lentil had lower SID of AA than SBM. However, lentil and SBM were similar in NE value; therefore, lentil can serve as alternative pulse feedstuff for pigs. The AA in EHC were mostly completely digested indicating that EHC can be fed to estimate ileal endogenous AA losses.

Impact of tylosin phosphate and distillers dried grains with solubles on energy and nutrient digestibility and flow through the gastrointestinal tract in growing pigs1

The objective of this study was to evaluate the impact of tylosin phosphate (TP) on energy and nutrient digestibility and flow through the gastrointestinal tract in growing pigs fed corn-soybean meal or corn-soybean meal-distillers dried grains with solubles (DDGS) based diets. Eighteen barrows (initial BW = 32.6 ± 1.2 kg) were surgically fitted with a T-cannula in the distal ileum and allotted to a Youden square design with 6 diets and 3 replicate periods. Treatments were arranged in a 2 × 2 factorial: TP (0 vs. 44 mg/kg) and DDGS (0 vs. 25%). Two N-free dietary treatments (0 vs. 44 mg/kg TP) were also included for determining basal ileal endogenous AA losses (IAAend) and the effect of TP on basal IAAend. Replicate periods included 4 d of adaptation to treatments and 2 sampling periods. Fecal collection occurred on d 5 and 6 and ileal digesta collection occurred on d 7 and 8 for sampling period 1 whereas sampling period 2 included fecal collection on d 11 and 12 and ileal digesta collection on d 13 and 14. Apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) were calculated for DM, energy, and NDF. The AID and standardized ileal digestibility (SID) of AA were calculated. Inclusion of DDGS reduced AID (68.0 vs. 72.8%; P < 0.001) and ATTD (79.9 vs. 85.0%; P < 0.001) of energy. There were no effects of TP on energy digestibility. The DDGS inclusion increased the amount of GE (1.47 vs. 1.18 Mcal/kg DMI; P < 0.001) and NDF (94 vs. 60 g/kg DMI; P < 0.001) remaining at the terminal ileum; however, hindgut disappearance of energy (0.55 vs. 0.53 Mcal/kg DMI) and NDF (13 vs. 15 g/kg DMI) was similar between the corn-soybean meal-DDGS and corn-soybean meal based diets. There were no effects of TP on basal IAAend; therefore, SID AA values were calculated using means of the 2 N-free diets. The SID of Lys (79.6 vs. 84.1%; P < 0.001) and all other indispensible AA, except Leu, was lower in the DDGS diets. Inclusion of TP did not influence SID of AA. In conclusion, under the conditions of this experiment, TP did not affect digestibility of AA or the digestibility and gastrointestinal tract flow of energy and the inclusion of DDGS did not affect the response to TP.

Amino acid and phosphorus digestibility and concentration of digestible and metabolizable energy in hydrolyzed feather meal fed to growing pigs1

Two experiments were conducted to determine the standardized ileal digestibility (SID) of AA (Exp. 1), the standardized total tract digestibility (STTD) of P, and the concentration of DE and ME (Exp. 2) in hydrolyzed feather meal (FM) fed to growing pigs. Eight samples of FM were obtained from 4 different processing plants (FM1, FM2, FM3, and FM4). Each plant provided samples of FM without and with added blood. In Exp. 1, 10 barrows (initial BW: 24.0 ± 0.8 kg) were prepared with a T-cannula in the distal ileum and allotted to a 10 × 10 Latin square design with 10 diets and ten 7-d periods. A N-free diet, a diet based on soybean meal (SBM), and 8 diets based on a combination of SBM and each of the 8 sources of FM were formulated. Values for the SID of CP and AA in each source of FM were calculated using the difference procedure. The SID of CP and all AA was different (P < 0.001) among sources of FM. Among the indispensable AA, the overall effect of addition of blood was statistically significant (P < 0.05) for the SID of Ile, Leu, Lys, Phe, and Val, but for some sources, the SID of these AA was increased by addition of blood, whereas for other sources, the SID was reduced or not changed (interaction, P < 0.05). As an example, the SID of Lys in FM3 and FM4 with added blood were greater (P < 0.05) than in FM3 and FM4 without blood, but no difference in the SID of Lys was observed for FM1 and FM2 without and with blood (interaction, P < 0.01). In Exp. 2, 72 growing barrows (initial BW: 13.3 ± 1.5 kg) were used with 9 diets and 8 replicate pigs per diet. A corn-diet consisting of 98.4% corn was formulated and 8 additional diets were formulated by mixing corn with 25% FM. The STTD of P and the DE and ME of each source of FM were calculated using the difference procedure. The STTD of P tended (P = 0.09) to be different among FM sources and the STTD of P in FM with added blood was less than in FM without blood. On a DM basis, DE and ME values were affected (P < 0.05) by both source of FM and addition of blood. However, an interaction (P < 0.05) between source of FM and addition of blood for ME was observed because addition of blood to FM3 and FM4 reduced (P < 0.05) the ME, whereas addition of blood to FM1 and FM2 had no impact on ME. In summary, the SID of AA, STTD of P, and the energy concentration vary among sources of FM and the effects of adding blood to FM is not consistent among sources.

Prediction of the concentration of standardized ileal digestible amino acids in distillers dried grains with solubles1

Values for the concentration of standardized ileal digestible (SID) CP, Lys, Met, Thr, and Trp from 34 sources of distillers dried grains with solubles (DDGS) were obtained from a series of 5 experiments with the objective of predicting the concentration of SID AA from physical and chemical assays. The concentration of NDF, ADF, hemicellulose, acid detergent insoluble CP (ADICP), and KOH soluble protein (SolCP) were measured and calculated in all DDGS sources. Likewise, particle size was measured and color of each source of DDGS was determined with a Minolta colorimeter and HunterLab spectrometer and was expressed as lightness (L*), redness (a*), and yellowness (b*). The HunterLab spectrometer also provided optical density that was recorded between 400 and 700 nm. Front face fluorescence was measured at 360 nm excitation and recorded from 380 to 600 nm. Multiple linear regression and principal components analyses were performed to predict the concentration of SID AA among DDGS sources, and predicted means as well as predicted residual sums of squares (PRESS) were calculated to estimate accuracy and precision of the model. Some correlations (P < 0.05) were observed between ADF, hemicellulose, ADICP, and SolCP with SID CP and AA but were generally low (r < 0.51). There was a greater association (R(2) = 0.40; P < 0.05) between L* and SID Lys among DDGS sources when L* was less than 50 than when samples had L* values greater than 50. In addition, a* was negatively correlated (P < 0.05) with SID CP (r = -0.41), Lys (r = -0.59), and Met (r = -0.50) whereas b* tended to be positively correlated (P < 0.10) with SID Lys (r = 0.31) and Trp (r = 0.30) and was correlated (P = 0.05) with SID Met (r = 0.43) and Thr (r = 0.36). There were no correlations between NDF or particle size with SID CP and AA. Optical density, along with CP, was highly predictive of SID Lys (R(2) = 0.97; PRESS = 0.05), Thr (R(2) = 0.94; PRESS = 0.06), and Trp (R(2) = 0.93; PRESS = 0.004) but not SID Met (R(2) = 0.39; PRESS = 0.12). Front face fluorescence was also highly predictive of SID Lys (R(2) = 0.99; PRESS = 0.07), Met (R(2) = 0.95; PRESS = 0.05), Thr (R(2) = 0.99; PRESS = 0.008), and Trp (R(2) = 0.99; PRESS = 0.006). In conclusion, correlations between ADICP, SolCP, NDF, particle size, and color measurements with SID AA concentrations were poor, but optical density and front face fluorescence methods appear to provide good predictions of SID AA concentrations in DDGS. However, these prediction equations need to be validated using samples of DDGS from a separate data set.

Effects of increasing co-product inclusion and reducing dietary protein on growth performance, carcass characteristics, and jowl fatty acid profile of growing–finishing pigs1

Dietary inclusion of co-products (Co-P) provides opportunities for diversifying the feedstuff matrix by using local feedstuffs, reducing feed costs, and producing value-added pork. In 2 studies, we determined effects of Co-P (canola meal, distillers dried grains with solubles, and co-extruded oil seed and field pea) inclusion level and reduced dietary CP concentration on growth performance, carcass characteristics, and jowl fatty acid profiles of growing-finishing pigs. Pigs were fed isoenergetic and isolysinic diets over 4 growth phases with 8 pen observations per dietary regimen. At slaughter, carcasses were characterized for all pigs and jowl fat was collected from 2 pigs per pen. In Exp. 1, 1,056 pigs (initial BW, 35.3 ± 0.4 kg) were fed 3 levels of dietary Co-P (low, mid, and high) and 2 CP concentrations (low and normal). Overall (d 0 to 86), increasing Co-P inclusion from low to mid or high decreased (P < 0.001) ADFI and ADG of pigs. Low CP concentration increased (P < 0.05) ADFI and ADG compared with normal CP concentration. An interaction (P = 0.026) occurred between dietary Co-P inclusion and CP concentration for G:F; low CP reduced (P < 0.05) G:F compared with normal CP for pig fed low Co-P, but G:F did not differ between CP concentrations for pigs fed mid and high Co-P. Increasing dietary Co-P inclusion from low to high increased (P < 0.001) α-linolenic acid (ALA) in jowl fat but decreased (P < 0.001) carcass weight and loin depth. In Exp. 2, 1,008 pigs (initial BW, 30.3 ± 0.4 kg) were assigned to 5 dietary regimens with Co-P increasing from 2.0 to 50.0% or a sixth regimen with 10% extra supplemental AA for the 37.5% Co-P diet. Overall (d 0 to 97), increasing Co-P inclusion did not affect ADFI, ADG, and G:F. Increasing dietary Co-P inclusion linearly decreased (P < 0.01) carcass weight, dressing percentage, backfat thickness, and loin depth but linearly increased (P < 0.001) jowl ALA. Supplementing 10% extra AA to the 37.5% Co-P diet did not affect growth performance or dressing percentage but increased (P = 0.014) carcass leanness and decreased (P = 0.023) backfat thickness compared with the 37.5% Co-P diet, indicating that dietary AA supply did not limit BW gain. In conclusion, Co-P can be included by up to 50% in diets for growing-finishing pigs without affecting G:F. However, increasing dietary Co-P may reduce ADG, ADFI, and carcass weight even if diets are balanced for dietary NE and standardized ileal digestible AA content.

Digestibility energy and amino acids of canola meal from two species (Brassica juncea and Brassica napus) fed to distal ileum cannulated grower pigs1

Yellow-seeded Brassica juncea is a novel canola species targeted to grow in the southern Canadian prairies where thermotolerance, disease resistance, and adaptation to dry agronomic conditions are required. The support of its cultivation needs nutritional evaluation of its coproduct. The B. juncea canola meal (CM) contains less fiber than conventional, dark-seeded Brassica napus CM but also slightly less Lys. In a 6 × 6 Latin square, 6 distal ileum cannulated pigs (47 kg BW) were fed 6 diets to determine the apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of CP and AA, AID and apparent total tract digestibility (ATTD) of energy, and VFA content in digesta and feces. Pigs were fed 6 diets: basal [46% wheat (Triticum aestivum) and corn (Zea mays) starch], 4 diets with 46% wheat and either B. juncea or B. napus CM at 25 or 50%, and a N-free diet based on corn starch. The B. juncea CM had higher (P < 0.05) ATTD of energy than B. napus CM (68.6 vs. 60.3%) likely due to its lower fiber content. Ileal total VFA was lower (P < 0.001) in pigs fed B. juncea than B. napus CM diets. In pigs fed B. juncea CM, the molar ratio in digesta was lower (P < 0.001) for acetate and butyrate whereas the propionate ratio was lower (P < 0.001) in feces than in pigs fed B. napus CM diets. The CM species did not affect the AID of energy, SID of AA, and feces VFA content. The DE value was higher (P < 0.05) and content of SID Lys was lower (P < 0.05) for B. juncea than B. napus CM. In conclusion, availability of B. juncea CM, a coproduct of a canola species grown in Canadian prairie land, will increase flexibility in swine feed formulation.

Comparative evaluation of standardized ileal amino acid digestibility in protein supplements for piglets1,2

Standardized ileal digestibility (SID) of AA was determined in 6 protein ingredients for piglets. A basal diet based on corn (Zea mays) starch and casein was supplemented with fluid-bed-dried porcine intestinal mucosa hydrolysate, spray-dried porcine intestinal mucosa hydrolysate, soy (Glycine max) protein concentrate, 2 batches of soy protein, or full-fat soybeans. The SID of AA did not differ between the 4 soybean products (P > 0.05). Compared to most SID values in the 4 soybean products, SID of AA were lower in the 2 porcine intestinal mucosa hydrolysates (P ≤ 0.05). In conclusion, although the initial trypsin inhibitor contents in the raw soybeans have not been determined, high SID values in the 4 soybean products indicate that the different processing procedures used to manufacture these products were efficient to inactivate trypsin inhibitors. For most AA in the 2 porcine intestinal mucosa hydrolysates, drying procedure did not affect SID of AA, but SID values were generally lower compared to the 4 soybean products.

Comparison of standardized ileal amino acid digestibilities in protein supplements and cereal grains for weaned pigs1

Standardized ileal digestibility (SID) of AA in protein ingredients and grains was determined in weaned piglets (5 kg initial BW) using the difference method. Animals were fitted with a simple ileal T-cannula on day 24 or 25 of age. A synthetic diet based on corn (Zea mays) starch and casein was either supplemented with an extruded soybean (Glycine max) meal (ESM), rice (Oryza sativa) protein concentrate (RPC), full fat heat-treated soybeans (SB), corn, barley (Hordeum vulgare), or wheat (Triticum aestivum). The contribution of CP and AA from casein and from the assay feed ingredients to the assay diet averaged 50% each. Each diet was fed to 6 animals according to a row-column design with 3 periods. Apparent ileal digestibility was corrected for basal ileal endogenous losses of AA to obtain SID values. Between RPC and soy products, differences (P < 0.05) in SID of most AA such as Lys, Met, and Thr were greater than within soybean products (ESM and SB). The SID of indispensable AA did not differ (P > 0.05) between barley and wheat, except for Met (P < 0.05). Furthermore, SID of Arg, His, Ile, Phe, and Trp was lower (P < 0.05) in corn than wheat. In conclusion, SID of most AA in the present study with piglets was lower than tabulated SID values determined in studies with grower-finisher pigs. Furthermore, the use of RPC, despite its high CP content, in diets for weaned piglets is limited due to its low SID of AA.

Effect of soybean meal origin on standardized ileal amino acid digestibility in piglets1

The present study with piglets was conducted to estimate standardized ileal digestibility (SID) of AA in European Union soybean (Glycine max) meal (SBM) imports sourced from Argentina, Brazil, and the United States. Twelve piglets with an average initial BW of 9 kg (47 d of age) were fitted with a simple ileal T-cannula to determine SID of AA in 4 batches of SBM originating either from Argentina (n = 1), Brazil (n = 1), or the United States (n = 2; US1 and US2). A semisynthetic diet based on corn (Zea mays) starch and casein (125 g casein/kg as-fed) was supplemented with 1 of 4 batches SBM at an inclusion rate of 235 g SBM/kg (as-fed) each. The chemical composition did not differ largely, with CP contents ranging from 458 in Argentinean to 461 g/kg (as-fed) in US1 SBM. The SID of indispensable AA ranged from 80% in US2 SBM to 83% in Argentinean SBM and from 74% for Trp in US2 and Brazilian SBM to 91% for Arg in US2, Brazilian, and Argentinean SBM. Most SID values did not differ among the SBM batches (P > 0.05). In conclusion, European SBM imports from Brazil, Argentina, or the United Sates were similar in their chemical composition. For most AA, high and uniform SID values were obtained independent from their source of origin.

Growth performance and preference studies to evaluate solvent-extracted Brassica napus or Brassica juncea canola meal fed to weaned pigs1

Inclusion of conventional dark-seeded (Brassica napus) and novel yellow-seeded (Brassica juncea) canola meal (CM) can potentially replace soybean (Glycine max) meal (SBM) in pig diets. Our objective was to examine the preference of weaned pigs fed diets containing SBM or B. napus or B. juncea CM and to compare it against previously reported growth performance data (Exp. 1 and 2). In Exp. 1 and 2, growth performance was evaluated using 220 and 240 weaned pigs, respectively, by replacing dietary SBM with up to 20% B. napus (Exp. 1) or 24% B. juncea CM (Exp. 2). Feeding up to 20% B. napus CM to pigs did not affect growth performance, but increasing inclusion of B. juncea CM linearly reduced (P < 0.001) ADFI, ADG, and G:F most likely due to the higher content of glucosinolates, particularly gluconapin in B. juncea CM as confirmed by principle component analysis. In Exp. 3 and 4, SBM and B. napus and B. juncea CM fed at 20% dietary inclusion were evaluated in 2 preference studies using 216 and 144 pigs of 35 d of age, respectively. Pens equipped with 2 feeders housed 8 or 4 pigs per pen, in Exp. 3 and 4, respectively. Diets formulated to equal NE and standardized ileal digestible AA were offered in a paired choice as mash (Exp. 3) or pellets (Exp. 4) for 3 consecutive 7-d periods (3 d nontest and 4 d preference test). The 3 treatments offered were (i) SBM vs. B. napus CM, (ii) SBM vs. B. juncea CM, and (iii) B. napus vs. B. juncea CM. Pigs preferred SBM (P < 0.001) over B. napus and B. juncea CM diets, and pigs preferred B. napus (P < 0.001) over B. juncea CM diet. High content of the glucosinolate gluconapin likely reduced feed preference in B. juncea more than in B. napus CM. In conclusion, the contrast between preference and performance studies feeding CM to pigs indicates that preference studies should be interpreted cautiously until validated by growth performance data.

Effects of abrupt introduction and removal of high and low digestibility corn distillers dried grains with solubles from the diet on growth performance and carcass characteristics of growing-finishing pigs1

Two experiments were conducted to evaluate the effects of feeding continuously a diet containing 40% dried distillers grains with solubles (DDGS) or intermittently diets containing 20 or 40% DDGS on growth performance and carcass quality of pigs. Responses of the pigs to abrupt introduction and removal of dietary DDGS with differing concentrations of standardized ileal digestible (SID) AA were also evaluated. In Exp. 1, crossbred pigs (n=216; initial BW=51.3±3.1 kg) were assigned randomly to 1 of 4 treatments, which included a corn-soybean meal control (CON), a 20% DDGS diet (D20), a switch between D20 and CON (D20-CON), and a switch between a 40% DDGS diet and CON (D40-CON) with 6 pens per treatment. Pigs abruptly introduced and removed from a 20% DDGS diet (D20-CON) exhibited no differences in growth performance or carcass quality compared with CON pigs. However, intermittently feeding a 40% DDGS diet (D40-CON) resulted in lighter HCW (P<0.05) compared with all other treatments. In Exp. 2, crossbred pigs (n=324; initial BW=33.2±3.0 kg) were assigned randomly to 1 of 6 treatments, including a corn-soybean meal control (CON), a 40% low SID AA DDGS diet (LD), a 40% high SID AA DDGS diet (HD), LD and CON diets alternated (LD-CON), HD and CON diets alternated (HD-CON), or HD and LD diets alternated (HD-LD) with 6 pens per treatment. Final BW and ADG were less (P<0.05) for LD and HD-LD pigs compared with CON pigs, but HD pigs tended to have reduced (P<0.10) final BW and ADG. Loin muscle area was smaller for LD and HD-LD pigs compared with CON pigs (P<0.05). Percentage carcass lean was not affected by dietary treatment. Backfat of DDGS-fed pigs was more unsaturated than CON pigs, but AA digestibility of DDGS did not affect this response. Digestibility of AA in DDGS can influence pig performance and carcass quality when fed at high concentrations (40% or more). The use of a high SID AA DDGS source may diminish some of the negative responses observed for growth performance and carcass characteristics when feeding high concentrations of DDGS if accurate values of SID AA are used in diet formulation. Periodic inclusion and removal of 40% DDGS from diets did not adversely affect growth performance or carcass quality regardless of the SID AA digestibility of the DDGS used. These results indicate that it is possible to abruptly incorporate and remove DDGS from grower-finisher swine diets without meaningful detrimental effects on growth performance or carcass quality.

Effect of the dietary net energy concentration on feed intake and performance of growing-finishing pigs housed individually1

The effect of dietary NE content on feed intake and performance of pigs was investigated using crossbred barrows with initial and final BW of approximately 35 and 110 kg, respectively. Pigs were housed individually and allowed ad libitum access to feed. Pigs were randomly allotted to 6 wheat and soybean meal-based diets (8.1, 8.7, 9.3, 9.9, 10.5, and 11.1 MJ NE/kg) with 16 pigs/diet. Ratios between standardized ileal digestible AA and NE were similar in all diets. Over the entire experiment, increase in dietary NE concentration was associated with a decreased ADFI (3.216, 3.216, 3.122, 2.910, 2.732, and 2.684 kg/d, respectively, for diets containing 8.1 to 11.1 MJ NE/kg; linear, P < 0.01). The NE intake increased as dietary NE increased from 8.1 to 11.1 MJ NE/kg (26.04, 27.98, 29.03, 28.81, 28.68, and 29.77 MJ/d, respectively; linear, P < 0.01, and quadratic, P = 0.06). Average daily gain increased when dietary NE concentration increased (1.046, 1.126, 1.135, 1.177, 1.156, and 1.152 kg/d, respectively, for diets containing 8.1 to 11.1 MJ NE/kg; linear and quadratic, P < 0.01). The increase in dietary NE concentration was associated with an increase in dressing percentage (76.5, 77.0, 77.4, 78.0, 78.2, and 78.4% of BW; linear, P < 0.01) but no differences in lean percentage (58.3, 57.9, 58.0, 57.3, 58.1, and 56.4% of HCW, respectively, for diets containing 8.1 to 11.1 MJ NE/kg; P = 0.12). When dietary NE concentration increased from 8.1 to 11.1 MJ/kg, the G:F increased (0.326, 0.352, 0.364, 0.405, 0.425, and 0.428 kg/kg, respectively; linear, P < 0.01), but the G:F expressed using the NE system did not change (G:F, 39.97 g/MJ NE; P = 0.44). When adjusted to the same dressing yield and lean percentage, the differences in adjusted ADG increased among treatments, but the adjusted G:F expressed using the NE system was not influenced by dietary energy concentration. These results confirm the ability of individually housed pigs to adjust their spontaneous feed intake over a very wide range of NE concentrations (8.7 to 10.5 MJ/kg). Under commercial conditions, pigs may experience less variation in ADFI than the results obtained in this experiment because of differences in dietary energy concentrations. However, it seems that only a severe reduction in dietary energy concentration will be effective in restricting energy intake of pigs that are allowed ad libitum access to feed.

Standardized ileal digestible tryptophan-to-lysine ratios in growing pigs fed corn-based and non-corn-based diets1,2

Two 21-d experiments were conducted to determine the optimum standardized ileal digestible (SID) Trp:Lys in growing pigs fed corn-based diets compared with non-corn-based diets. The primary response variables in both experiments were ADG and plasma urea N (PUN) concentrations with the optimum SID Trp:Lys determined using broken-line analysis. Experiment 1 evaluated the optimum SID Trp:Lys in growing pigs fed corn-based diets consisting primarily of corn with minor inclusion of Canadian field peas and corn gluten meal to keep the SID Trp:Lys low. This experiment used 120 crossbred pigs (initial BW: 25.73 ± 2.46 kg) that were blocked by sex and initial BW and allotted to 5 SID Trp:Lys with 5 pens each for the first 4 treatments and 4 pens for the last treatment and 5 pigs/pen. Diets were formulated by the addition of supplemental Trp to create various SID Trp:Lys (12.77, 14.07, 15.50, 16.91, and 17.94%) with a constant SID Lys of 0.66%, which was determined to be 83% of the Lys requirement for pigs at this location. As the SID Trp:Lys increased from 12.77 to 17.94%, ADG increased (0.562, 0.648, 0.788, 0.787, and 0.815 kg/d) linearly (P < 0.001) and quadratically (P = 0.009), resulting in an optimum SID Trp:Lys of 15.73% (P < 0.001). Plasma urea N decreased (10.43, 9.30, 8.21, 8.55, and 9.25 mg/dL) linearly (P = 0.069) and quadratically (P = 0.015), resulting in an optimum SID Trp:Lys of 15.83% (P = 0.007). Experiment 2 evaluated the optimum SID Trp:Lys in growing pigs fed non-corn-based diets consisting primarily of barley and Canadian field peas, with smaller proportions of corn and wheat. Experiment 2 used 120 crossbred pigs (initial BW: 28.49 ± 2.92 kg) that were allotted to 5 increasing SID Trp:Lys (13.05, 14.32, 15.59, 16.85, and 18.11%; 0.66% SID Lys) in the same manner as Exp. 1. As SID Trp:Lys increased in Exp. 2, ADG increased linearly (P = 0.007) with the optimum SID Trp:Lys of 15.99% (P = 0.048). Plasma urea N concentrations decreased linearly (P = 0.056) and quadratically (P = 0.067) as SID Trp:Lys increased, resulting in an optimum SID Trp:Lys of 15.29% (P = 0.009). Averaging the break point values for ADG and PUN obtained from broken-line analysis for Exp. 1 and 2 produced optimum SID Trp:Lys of 15.78 and 15.64%, respectively. Based on the results from these 2 experiments, it seems that the optimum SID Trp:Lys is virtually unaffected by the dietary feedstuffs used as long as the diets are formulated on an SID AA basis.

Glycemic index of starch affects nitrogen retention in grower pigs1

Three studies were performed to examine the effect of starch and protein digestion rates on N retention in grower pigs. In Exp. 1, the glycemic index (GI) of corn, a malting barley, and a slow-rumen-degradable barley (SRD-barley) were measured using 6 barrows (BW = 18.0 ± 0.5 kg). The GI of malting barley was greater (P < 0.05) than that of SRD-barley (71.1 vs. 49.4), and the GI of both barley cultivars was less (P < 0.05) than that of corn (104.8). In Exp. 2, the standardized ileal digestibility of AA and DE content of the 3 ingredients were determined using 5 ileal-cannulated barrows (BW = 20.7 ± 2.3). The apparent total-tract energy digestibility values of corn (86.1%) and malting barley (85.7%) were greater (P < 0.05) than that of SRD-barley (82.3%). The standardized ileal digestibility of Lys was 94.0, 92.6, and 92.4% for corn, malting barley, and SRD-barley, respectively, and did not differ among grains. In Exp. 3, 6 diets were formulated to equal DE (3.40 Mcal/kg), standardized ileal digestibility of Lys (8.6 g/kg), starch (424.9 g/kg), and digestible CP (180.0 g/kg) using the values obtained in Exp. 2. Three GI [high (corn), medium (malting barley), and low (SRD-barley)] and 2 rates of protein digestion [rapid (soy protein hydrolysate) and slow (soy protein isolate)] were tested in a 3 × 2 factorial arrangement with 36 barrows (BW = 32.2 ± 2.5 kg). Pigs were fed 3.0 times the maintenance energy requirement daily in 2 meals for 2 wk and were housed in metabolic crates to collect feces and urine separately. At the end of the study, intestinal contents were collected from 4 equal-length segments of the small intestine. The percentage of unabsorbed CP in segment 1 relative to dietary CP was greater (P < 0.05) for the soy protein isolate diet than for the soy protein hydrolysate diet (170.3 vs. 116.5%). The percentages of unabsorbed starch in segments 1 and 2 were greater (P < 0.05) for the SRD-barley diet than for the malting barley or corn diet. Nitrogen intake and fecal N excretion were greater (P < 0.05) for pigs fed the malting barley and SRD-barley diets than for pigs fed the corn diet. Urinary N excretion was greater (P < 0.05) for pigs fed the SRD-barley diet than for pigs fed the corn or malting barley diet. Pigs fed slowly digestible starch (SRD-barley; 46.6%) had less (P < 0.05) net N retention than pigs fed corn or malting barley (54.7 and 54.1%, respectively). In conclusion, slowly digestible starch sources such as SRD-barley may not be suitable to support maximum protein deposition in restricted-fed grower pigs.