Chemical composition,energy and amino acid digestibility in double-low rapeseed meal fed to growing pigs

Background

The nutritional value of rapeseed meal may be variable due to the variation of its chemical composition. And a precise understanding of the nutritional value of an ingredient is beneficial for the accurate diet formulation and reduction of feed costs. This study was conducted to determine the chemical composition, digestible energy (DE) and metabolizable energy (ME) content, and apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of amino acids (AA) for growing pigs. Thirteen solvent-extracted double-low rapeseed meal (DLRSM) samples were obtained from the main double-low rapeseed producing areas in China.

Methods

The DE and ME contents of the 13 DLRSM samples were measured in growing pigs (six pigs per DLRSM sample, average initial body weight (BW) = 48.3 kg). The AID and SID of AA of 10 DLRSM samples were determined in 12 crossbred barrows (average initial BW = 35.3 kg) by using two 6 × 6 Latin square designs. Each Latin square comprised one N-free diet and 5 DLRSM test diets.

Results

The chemical composition of DLRSM varied among samples, and the coefficient of variation was greater than 10 % for ether extract (EE), neutral detergent fiber (NDF), acid detergent fiber (ADF), calcium (Ca), and total glucosinolates. The AA content of DLRSM varied among samples especially for lysine (Lys) and methionine (Met). On a dry matter (DM) basis, the apparent total tract digestibility (ATTD) of gross energy (GE), the DE and ME and the ME:DE ratio of DLRSM averaged 62.39 %, 2862 kcal/kg and 2723 kcal/kg, and 94.95 %, respectively. The mean value of SID of Lys was 70.52 % which varied from 66.54–76.54 %. The SID of crude protein (CP), Met, and threonine (Thr) averaged 72.81 %, 82.41 %, and 69.76 %, respectively.

Conclusions

There was great variability in chemical composition especially in the concentration of EE, NDF and ADF, but no significant differences in energy content of the DLRSM samples were observed. In addition, the AID and SID of all AA were relatively similar among DLRSM samples except for that of Lys.     

Amino acid digestibility in heated soybean meal fed to growing pigs

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

Responses of non-starch polysaccharide-degrading enzymes on digestibility and performance of growing pigs fed a diet based on corn, soya bean meal and Chinese double-low rapeseed meal

This study was conducted to investigate the effect of two distinct enzyme preparations on nutrients' digestibility and growth performance of growing pigs fed diets based on corn, soya bean meal and Chinese double-low rapeseed meal (DLRM). The two enzyme preparations were Enzyme R, a preparation extracted from fermentation of a non-GMO fungus Penicillum funiculosum, developed for multi-grain and multi-animal species; and Enzyme P, a xylanase preparation from Trichoderma longibrachiatum, for pigs fed corn-based diets only. Both enzymes were tested at 0, 0.25 and 0.50 g/kg feed using 70 crossbred male pigs (Large Yorkshire x Landrace) in five dietary treatments and seven replicates in each treatment, for growth period from 27 to 68 kg live weight in 49 days. Results showed that the supplementation of both enzymes (1) increased total-tract digestibility of dietary energy from 77.5% (control) to 81.4% (Enzyme R, p < 0.05) and 81.9% (Enzyme P, p < 0.05); of neutral detergent fibre from 41.0% (control) to 57.8% (Enzyme R, p < 0.05) and 60.0% (Enzyme P, p < 0.05); (2) improved average daily gain from 786 g (control) to 829 g (Enzyme R, p < 0.05) and 846 g (Enzyme P, p < 0.05); and numerical increases in feed intake from 1.96 kg/pig/day (control) to 2.01 (Enzyme R) and 2.00 (p > 0.05) and feed conversion ratio from 2.50 (control) to 2.42 (Enzyme R) and 2.36 (Enzyme P, p < 0.05); (3) there was a dose response but no significant differences were observed in enzyme efficacy between the two enzyme preparations. The present study demonstrated beneficial effects of applying xylanase-based enzymes to improve feeding values of pig diets based on corn, soya bean meal and DLRM.     

Standardized ileal digestibility of amino acids in European soya bean and rapeseed products fed to growing pigs

This study was conducted to determine the chemical composition and standardized ileal digestibility coefficients (SID) of crude protein (CP) and amino acids (AA) of European soya bean and rapeseed products in pigs. Six soya bean and two rapeseed products were used as the sole dietary source of CP and AA, including raw (FFSB) and roasted full‐fat soya beans (FFSB_Roasted), soya bean (SBC) and rapeseed cake (RSC), and rapeseed meal (RSM) from Bavaria (Germany), soya bean meal (SBM) from the Danube region (Austria; SBM_Austria), a commercially available standard SBM (SBM_Std) and an imported genetically modified organism‐free SBM (SBM_GMO‐free). Eight ileal‐ cannulated pigs with an initial body weight of 32 ± 2 kg were allotted to a row‐column design with eight diets and six periods of seven days each. Trypsin inhibitor activity (TIA) ranged from 1.8 in SBM_Std to 24.5 mg/g DM in FFSB. The SID of CP and all AA in FFSB_Roasted were greater than in FFSB, but lower when compared to SBC and SBM_Austria (p < .05). The SID of CP and all AA (except glutamic acid) were not different between SBC and SBM_Austria, but the SID of CP and all AA (except methionine) were greater (p < .05) in SBC than in SBM_GMO‐free. Furthermore, the SID of CP and most AA showed a quadratic response with decreasing TIA, and there exists a quadratic response in SID of CP and all AA with increasing lysine to CP ratio and neutral detergent insoluble nitrogen (p < .05). In conclusion, variation in chemical composition and SID of CP and AA was observed in different European soya bean and rapeseed products as influenced by differences in processing conditions. European SBC and SBM_Austria can be used as alternative to imported SBM_GMO‐free and SBM_Std in diets for growing pigs.     

Net energy of corn,soybean meal and rapeseed meal in growing pigs

Background: Two experiments were conducted to estimate the net energy(NE) of corn, soybean meal, expel er-pressed rapeseed meal(EP-RSM) and solvent-extracted rapeseed meal(SE-RSM) using indirect calorimetry and to validate the NE of these four ingredients using pig growth performance.Methods: In Exp.1, 24 barrows(initial BW = 36.4 ± 1.6 kg) were allotted to 1 of 4 diets which included a corn basal diet,a corn-soybean meal basal diet and two rapeseed meal diets containing 20% EP-RSM(9.5% ether extract) or SE-RSM(1.1% ether extract) substituted for corn and soybean meal. The design allowed the calculation of NE values of corn,soybean meal and rapeseed meals according to the difference method. In Exp.2, 175 growing pigs(initial BW = 36.0± 5.2 kg) were fed 1 of 5 diets for 28 d, with five pigs per pen and seven replications(pens) per treatment in order to validate the measured energy values. Diets were a corn-soybean meal diet and four diets including 10% or 20% EP-RSM and 10% or 20% SE-RSM.Results: The NE of corn, soybean meal, EP-RSM and SE-RSM were 12.46, 11.34, 11.71 and 8.83 MJ/kg DM, respectively. The NE to ME ratio of corn(78%) was similar to tabular values, however, the NE to ME ratios of soybean meal(70%) and rapeseed meal(76%) were greater than tabular values. The greater NE value in EP-RSM than in SE-RSM is consistent with its higher EE content. Increasing EP-RSM or SE-RSM did not affect the growth performance of pigs and the caloric efficiency of NE was comparable for al diets.Conclusions: The NE of EP-RSM was similar to soybean meal, and both were greater than SE-RSM. The DE, ME and NE values measured in Exp.1 are confirmed by results of Exp. 2 with comparable caloric efficiencies of DE, ME or NE for all diets.     

Digestible and metabolizable energy concentrations and amino acid digestibility of dried yeast and soybean meal for growing pigs

Energy values and amino acid (AA) digestibility of dried yeast (DY) and soybean meal (SBM) were determined in 2 experiments with growing pigs. Experiment 1 was conducted to determine the digestible energy (DE) and metabolizable energy (ME) in DY and SBM. Thirty barrows with a mean initial body weight (BW) of 20.6 kg (SD = 1.04) were assigned to 5 dietary treatments in a randomized complete block design with period and BW as blocking factors. A reference diet was prepared with corn, canola meal, and soybean oil as energy-contributing ingredients. Four additional diets were prepared by adding 5% and 10% DY or SBM at the expense of energy-contributing ingredients in the reference diet. The ratio of corn, canola meal, and soybean oil was kept consistent across the experimental diets. Each experimental period consisted of 5-d adaptation and 5-d quantitative collection of feces and urine. Test ingredient-associated DE or ME intake (kcal/d) was regressed against test ingredient intake [kg dry matter (DM)/d] to estimate the DE or ME in test ingredients as the slope of linear regression model. The DE in DY was estimated at 3,933 kcal/kg DM, which was not different from the estimated DE in SBM at 4,020 kcal/kg DM. Similarly, there was no difference between DY and SBM in the estimated ME (3,431 and 3,756 kcal/kg DM, respectively). Experiment 2 was conducted to determine the standardized ileal digestibility (SID) of AA in DY and SBM. Twenty-one barrows with a mean initial BW of 20.0 kg (SD = 1.31) were surgically fitted with T-cannulas at the distal ileum and assigned to 3 dietary treatments in a randomized complete block design with BW as a blocking factor. Two semi-purified diets containing DY or SBM as the sole nitrogen source and one nitrogen-free diet (NFD) were prepared. The NFD was used to estimate the basal ileal endogenous losses of CP and AA. Pigs were fed the 3 diets for 5 d as adaptation, followed by 2 d of feeding with ileal digesta collection. The SID of AA, except Gly and Pro, in DY was less (P < 0.05) than in SBM. The SID of indispensable AA in DY ranged from 64.1% for Thr to 85.2% for Arg, and those in SBM ranged from 83.9% for Thr to 91.8% for Arg. In conclusion, energy values of DY are not different from those of SBM, whereas AA in DY is less digestible than in SBM. The estimated DE and ME as well as the SID of AA in DY and SBM can be used in diet formulation for growing pigs using these ingredients.     

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

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

Nitrogen balance and ileal amino acid digestibility in growing pigs fed diets reduced in protein concentration

Two studies were conducted to assess the effect of dietary protein reduction on N utilization, N excretion, and AA digestibility in growing pigs. The objective was to determine whether pigs fed diets with a reduced CP concentration could maintain the same N retention as pigs fed an adequate diet. The second objective was to test whether reducing dietary CP concentration decreases AA digestibility. In each study, six barrows were allotted to one of six dietary treatments in a Latin square design. Treatments consisted of four corn-soybean meal-based diets containing 15, 12, 9, and 6% CP, a casein-based diet containing 15% CP, and a protein-free diet. Crystalline AA were included in the 12, 9, and 6% CP diets. The indispensable:dispensable AA ratio was maintained at 45:55 with the addition of L-glutamic acid to the 9 and 6% CP diets. The casein-based and protein-free diets were used to determine endogenous total tract N and ileal AA losses. In the first study, total N losses and N absorbed decreased linearly (P < 0.001) as dietary CP concentration decreased from 15 to 6%. Both a linear (P < 0.001) and a quadratic (P < 0.05) decrease in N retention were found with decreasing dietary CP concentration. Nitrogen retained as a percentage of intake and absorbed increased (P < 0.001) as dietary CP concentration was reduced from 15 to 6%. In the second study, six barrows were surgically fitted with a T-cannula at the terminal ileum to determine ileal AA digestibility. For all dispensable and most indispensable AA, apparent and standardized ileal digestibility increased linearly (P 0.01, and for arginine, P < 0.05) as dietary CP concentration decreased. These results indicate that dietary CP concentration can be decreased from 15 to 12% with crystalline AA supplementation to meet an ideal AA profile without adversely affecting N retention, and that decreasing dietary CP concentration from 15 to 6% increases both dispensable and indispensable AA ileal digestibility.     

Ileal amino acid digestibility and performance of growing pigs fed wheat-based diets supplemented with xylanase

Two experiments were conducted to determine the effect of supplementation of xylanase to a wheat-based diet on the apparent ileal digestibility (AID) of AA and the performance of growing pigs fed diets limiting in AA. In Exp. 1, eight pigs (average initial BW = 20.5+/-1.2 kg) fitted with a simple T-cannula at the distal ileum, were fed four diets according to a repeated 4 x 4 Latin square design. Diet 1 was a basal diet that contained 97.6% wheat. Diets 2, 3, and 4 were the basal diet supplemented with xylanase at rates of 5,500, 11,000, and 16,500 units of xylanase activity (XU), respectively (as-fed basis). There were linear and quadratic effects (0.062 < P < 0.001) of xylanase supplementation on the AID of CP and most of the AA. The largest increases in AID of CP and AA were obtained when xylanase was supplemented at a rate of 11,000 XU; no further increases were observed with xylanase supplementation at a rate of 16,500 XU. In Exp. 2, 30 pigs (average initial BW 21.4+/-1.8 kg) were randomly allotted to six dietary treatments. Diets 1 to 4 were similar to those used in Exp. 1. Diet 5 was the same as Diet 1, but supplemented with 0.53% lysine, 0.12% threonine, and 0.05% methionine. Diet 6 (positive control diet) was a wheat-soybean meal diet that contained 18.2% CP (as-fed basis). The total contents of lysine, threonine, and methionine were similar for Diets 5 and 6. There was a linear effect of xylanase supplementation on ADG (P = 0.093) and feed:gain ratio (P = 0.089), and a quadratic effect on ADG (P = 0.067) and feed:gain ratio (P = 0.074). But, the greatest response was obtained with the supplementation of 11,000 XU. The supplementation of lysine, threonine, and methionine to Diet 1 increased (P = 0.001) ADG and ADFI and improved (P = 0.01) feed:gain ratio. There was no difference (P = 0.508) in the performance of pigs fed the AA-supplemented or control diet. In conclusion, the supplementation of xylanase to a diet in which wheat provided the sole source of protein and energy improved the AID of AA, ADG, and feed:gain ratio; however, this improvement was very small compared with that obtained with the supplementation of synthetic amino acids.     

Energy, phosphorus, and amino acid digestibility of high-protein distillers dried grains and corn germ fed to growing pigs

Three experiments were conducted to measure energy, P, and AA digestibility in 2 novel co-products from the ethanol industry [i.e., high-protein distillers dried grains (HP DDG) and corn germ]. These products are produced by dehulling and degerming corn before it enters the fermentation process. Experiment 1 was an energy balance experiment conducted to measure DE and ME in HP DDG, corn germ, and corn. Six growing pigs (initial BW, 48.9 +/- 1.99 kg) were placed in metabolism cages and fed diets based on corn, corn and HP DDG, or corn and corn germ. Pigs were allotted to a replicated, 3 x 3 Latin square design. The DE and ME in corn (4,056 and 3,972 kcal/kg of DM, respectively) did not differ from the DE and ME in corn germ (3,979 and 3,866 kcal/kg of DM, respectively). However, HP DDG contained more (P < 0.05) energy (4,763 kcal of DE/kg of DM and 4,476 kcal of ME/kg of DM) than corn or corn germ. Experiment 2 was conducted to measure apparent total tract digestibility (ATTD) and true total tract digestibility of P in HP DDG and corn germ. Thirty growing pigs (initial BW, 33.2 +/- 7.18 kg) were placed in metabolism cages and fed a diet based on HP DDG or corn germ. A P-free diet was used to measure endogenous P losses. Pigs were assigned to treatments in a randomized complete block design, with 10 replications per treatment. The ATTD and the retention of P were calculated for the diets containing HP DDG and corn germ, and the endogenous loss of P was estimated from pigs fed the P-free diet. The ATTD was lower (P < 0.05) in corn germ (28.6%) than in the HP DDG (59.6%). The retention of P was also lower (P < 0.05) in pigs fed corn germ (26.7%) than in pigs fed HP DDG (58.9%). The endogenous loss of P was estimated to be 211 +/- 39 mg per kg of DMI. The true total tract digestibility of P for HP DDG and corn germ was calculated to be 69.3 and 33.7%, respectively. In Exp. 3, apparent ileal digestibility and standardized ileal digestibility values of CP and AA in HP DDG and corn germ were measured using 6 growing pigs (initial BW, 78.2 +/- 11.4 kg) allotted to a replicated, 3 x 3 Latin square design. The apparent ileal digestibility for CP and all AA except Arg and Pro, and the standardized ileal digestibility for CP and all AA except Arg, Lys, Gly, and Pro were greater (P < 0.05) in HP DDG than in corn germ. It was concluded that HP DDG has a greater digestibility of energy, P, and most AA than corn germ.     

True ileal amino acid digestibility and endogenous ileal amino acid losses in growing pigs fed wheat shorts- or casein-based diets

Use of dietary AA in growing pigs reflects digestion and use of digested AA for various body functions. Before evaluating dietary effects on use of digestible AA intake for body protein deposition, a digestibility study was conducted to investigate true ileal AA digestibility and endogenous ileal AA losses in growing pigs fed graded levels of wheat shorts (WS) or casein (CS; control). A casein-based basal diet (basal) was formulated to contain 0.27 g of standardized ileal digestible (SID) Lys per MJ of DE, to which extra Lys was added from WS (WS2, +0.10 g of SID Lys per MJ of DE; WS3, +0.20 g of SID Lys per MJ of DE) or casein (CS3, +0.20 g of SID Lys per MJ of DE). A fifth diet was formulated to be similar in CP level and source as CS3 but in which 6% pectin, a source of soluble non-starch polysaccharides (NSP), was included at the expense of cornstarch (CS3 + pectin). Five Yorkshire barrows (17.5 +/- 1.5 kg of BW) were fitted with a T-cannula at the distal ileum and randomly assigned to 1 of the 5 experimental diets in a 5 x 5 Latin Square design. Apparent ileal digestibility (AID), true ileal digestibility (TID), and endogenous ileal protein losses (EPL) were determined using the homoarginine method. Diet CS level did not influence (P > or = 0.10) TID of most essential AA or EPL (10.4 g/kg of DM intake). Including pectin in the diet did not influence TID of AA (P > or = 0.10) but increased EPL (15.6 g/kg of DM intake; P > or = 0.01). Inclusion of WS in the diet reduced TID of most essential AA (P < 0.01). The TID values for most essential AA, however, were the same (P > or = 0.10) for both dietary WS levels, except for Lys and Met, which were further reduced at the greatest dietary WS level. Increased EPL (P < 0.01) was only observed for WS3 (16 g/kg of DMI). We concluded that (1) the effects of dietary protein source on AID of AA can be attributed both to reduced TID of AA and increased EPL, (2) the impact of dietary WS level on TID of AA and EPL does not seem to be linear, (3) soluble NSP from pectin or WS exerts a greater effect on EPL than insoluble NSP, and (4) because of the metabolic cost associated with EPL and the impacts of feed composition on microbial fermentation in the gut lumen, the effects of feed ingredients on the use of ileal digestible AA for protein deposition should be investigated further.     

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.     

Determination and prediction of the apparent and standardized ileal amino acid digestibility in cottonseed meals fed to growing pigs

This experiment was conducted to evaluate the chemical composition and apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of amino acids (AA) in cottonseed meals (CSM) and to develop prediction equations for estimating AA digestibility for growing pigs based on the chemical composition and AA content of CSM. 10 CSM were collected from 10 provinces in China. 11 barrows (initial body weight: 34.4 ± 1.9 kg), fitted with an ileal T‐cannula, were allotted to 6 × 11 Youden square with 6 periods and 11 diets. The diets included one N‐free diet and 10 CSM test diets containing 40% CSM as the sole source of AA. The nitrogen‐free diet was used to measure the basal endogenous losses of CP and AA. The AID and SID for crude protein (CP), Lys, Met, Trp, and Thr among the 10 CSM differed (p < 0.05). With R² values exceeding 0.30, significant linear regression equations for CP, Lys, and Thr were obtained. The best fit equations for predicting the AID and SID of Lys were: AID of Lys = 82.94–0.65 neutral detergent fiber, with R² = 0.44, residual standard deviation (RSD) = 4.03 and p = 0.04; and SID of Lys = 135.34–1.01 neutral detergent fiber + 34.27 Thr – 58.06 Trp – 84.93 Met, with R² = 0.90, RSD = 1.42 and p = 0.01. In conclusion, the results of AID, SID and prediction equations could be used to evaluate the digestibility of CSM in growing pigs.     

Calcium, phosphorus, and amino acid digestibility in low-phytate corn, normal corn, and soybean meal by growing pigs

Nine growing barrows were equipped with a T-cannula in the distal ileum and used to determine apparent ileal (AID) and apparent total-tract digestibility (ATTD) coefficients of Ca and P in low-phytate corn, normal corn, soybean meal, and in diets where soybean meal was mixed with low-phytate corn or normal corn. The AID and the standardized ileal digestibility coefficients (SID) of CP and AA also were determined. The animals (initial BW = 29.3 +/- 1 kg) were allotted to a 9 x 9 Latin square with nine diets and nine periods. Three diets contained low-phytate corn, normal corn, and soybean meal as their sole source of CP, AA, Ca, and P, respectively. Three additional diets were identical to these diets except that limestone and monosodium phosphate were added. Two diets contained low-phytate corn or normal corn and soybean meal, limestone, and monosodium phosphate, and the final diet was a N-free diet. The AID and ATTD of Ca were higher (P < 0.05) for low-phytate corn than for normal corn (70.0 and 69.1% vs. 47.4 and 49.6%, respectively). The AID and ATTD for Ca in soybean meal (50.9 and 46.7%, respectively) did not differ from values for normal corn but were lower (P < 0.05) than for low-phytate corn. The AID and ATTD for P from low-phytate corn (56.5 and 54.5%, respectively) were greater (P < 0.05) than from normal corn (28.3 and 28.8%, respectively), whereas soybean meal had intermediate AID and ATTD for P (37.2 and 38.0%, respectively). The AID and ATTD of P increased (P < 0.05) when monosodium phosphate was added to normal corn (44.9 and 49.8%, respectively) and soybean meal (49.6 and 46.2%, respectively), but adding monosodium phosphate to low-phytate corn, did not alter either AID (49.7%) or ATTD (50.7%) of P. No differences between AID and ATTD for Ca or P within the same diet were observed. The AID of Arg, Asp, Gly, Ile, Lys, Phe, Thr, and Val were greater (P < 0.05) in low-phytate corn than in normal corn. The AID of all AA in soybean meal were greater (P < 0.05) than in both types of corn, with the exception of Ala, Cys, Leu, and Met. The SID of Lys, Phe, and Thr were higher (P < 0.05) in low-phytate corn than in normal corn. Because low-phytate corn has a higher digestibility of Ca and P, less inorganic Ca and P need to be supplemented to diets containing low-phytate corn than to those containing normal corn, and P excretion may be decreased when low-phytate corn is used in the diet.     

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.     

Phosphorus digestibility and energy concentration of enzyme-treated and conventional soybean meal fed to weanling pigs

Two experiments were conducted to determine the apparent total tract digestibility (ATTD) of P and the concentration of DE and ME in enzyme-treated soybean meal (SBM) and in conventional soybean meal (SBM-CV). Phosphorus digestibility in 2 enzyme-treated SBM (HP-310 and HP-340) and in SBM-CV was measured using 36 barrows (initial BW: 21.9 ± 1.1 kg) that were housed in metabolism cages and randomly allotted to 6 diets with 6 replicates per diet. During production, HP-310 had been treated with an enzyme mixture containing no phytase, whereas HP-340 was treated with an enzyme mixture that contained exogenous phytase. Three diets containing HP-310, HP-340, or SBM-CV as the sole source of P were formulated. Three additional diets also contained HP-310, HP-340, and SBM-CV, but each of these diets was fortified with 500 units of microbial phytase. The ATTD of P in HP-310 and SBM-CV increased (P < 0.05) as phytase was included in the diet (from 59.8 to 77.7% for HP-310 and from 65.5 to 79.5% for SBM-CV), but the ATTD of P in HP-340 without and with phytase was not different (P > 0.05; 83.8 and 87.7%, respectively). There were no differences (P > 0.05) in the ATTD of P between HP-310 and SBM-CV, but the ATTD of P in HP-340 was greater (P < 0.05) than in the other 2 meals. The DE and ME in corn, 2 sources of enzyme-treated SBM (HP-200 and HP-310), and in SBM-CV were measured in the second experiment using 28 barrows housed in metabolism cages (initial BW: 16.8 ± 2.5 kg of BW). The process used to produce HP-200 is similar to that used to produce HP-310 except that HP-200 is exposed to the enzymes for a shorter period of time than HP-310. A corn-diet consisting of 96.45% corn and vitamins and minerals was formulated. Three additional diets were formulated by mixing corn and each source of SBM with vitamins and minerals. Pigs were randomly allotted to the 4 diets with 7 replicate pigs per diet, and urine and feces were collected quantitatively during the last 5 d of a 14-d feeding period. The concentration of DE in HP-200, HP-310, and SBM-CV was 4,333, 4,316, and 4,347 kcal/kg of DM, respectively. These values were not different (P > 0.05), but they were greater (P < 0.05) than the DE in corn (3,891 kcal/kg of DM). The concentration of ME was 3,780, 3,926, 3,914, and 3,980 kcal/kg of DM in corn, HP-200, HP-310, and SBM-CV, respectively. These values were not different (P > 0.05). It is concluded that enzyme treatment of SBM does not influence the digestibility of P or the concentration of DE and ME in the meals.     

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.     

Apparent and standardized ileal digestibility of amino acids in diverse barley cultivars fed to growing pigs

The objectives of this study were to determine the chemical composition, ileal amino acid (AA) digestibility of barley varieties and to develop equations to predict the AA digestibility based on the chemical characteristics of individual barley. A wide selection of nine barley varieties in the main growing regions of China was used in the experiment. Ten crossbred pigs (30.9 ± 1.8 kg) were allotted to a 6 × 10 Youden Square. The treatments included a nitrogen‐free diet and nine barley test diets. Considerable variation was observed in the content of neutral detergent fiber, acid detergent fiber, crude protein (CP) and all AAs among the barley samples. The standardized ileal digestibility (SID) of indispensable AAs with the exception of arginine, phenylalanine and threonine were different (P < 0.05) among the nine barley sources tested. With R² values exceeding 0.50, significant linear regression equations for CP and threonine were obtained. In conclusion, significant differences existed in the ileal digestibility of CP and AAs among barley varieties. It is difficult to predict the SID of most of the amino acids in barely based upon chemical characteristics.     

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.     

Determination of apparent ileal amino acid digestibility in rapeseed meal and cake processed at different temperatures using the direct and difference method with growing pigs.

Studies were conducted with ten barrows, average initial body weight 34.5 +/- 2.1 kg, fitted with a T-cannula at the distal ileum, to study the accuracy of determination of the apparent ileal digestibility (AID) values of crude protein (CP) and amino acids (AA) in rapeseed meal and cake and the effects of processing, using the difference method. Five corn starch-based diets in the studies were formulated to contain 17.7% CP and based on soybean meal, prepress-extraction rapeseed meal, prepress-extraction rapeseed meal plus soybean meal, high-temperature press rapeseed cake plus soybean meal, or low-temperature press rapeseed cake plus soybean meal as the sole source of dietary protein. The design was an incomplete Latin Square involving two three-week periods and five-treatments. It was found that the AID values of CP and most AA determined with the difference or direct method were significantly lower in rapeseed meal or cakes than soybean meal. The AID values of CP and most AA in prepress-extraction rapeseed meal, high-temperature press or low-temperature cakes determined with the difference method were no difference from those in prepress-extraction rapeseed meal determined with the direct method. The AID values of CP and AA in rapeseed meal and cake determined with the difference method were accurate, when the contribution of CP and AA from rapeseed was more than 50%. The AID values of CP and AA (especially lysine) were lower in the high-temperature press rapeseed cake than in the low-temperature press cake or the prepress-extraction meal.