Apparent Ileal Digestibility Of Lys Research Articles

PSI-12 Dietary isoacids modulate nutrient digestibility and fermentation products in ileal digesta and feces of growing pigs fed corn-soybean meal diets

Abstract Branched-chain fatty acids, or isoacids, are the product of branched-chain amino acid fermentation and have been associated with benefits on the productivity of ruminants, primarily by positively modulating gut microbes and promoting gastrointestinal health. The objective of this study was to determine the optimal inclusion level of isoacid blend product based on apparent ileal digestibility (AID), apparent total tract digestibility (ATTD) of nutrients, and fermentation products in growing pigs fed corn-soybean meal diets. Twelve cannulated pigs [body weight (BW) = 20.9 + 0.6 kg] were used in a 5-period switch-back design with 6 diets and 2 replicate pigs in each period (n = 10 observations per dietary treatment). Experimental diets consisted of increasing levels (0%, 0.5%, 0.75%, 1%, 1.25%, and 1.5%) of an isoacid blend (isobutyrate, isovalerate, and 2-methyl butyrate, 1:1:1) added to a corn-soybean meal basal diet containing titanium dioxide as an indigestible marker. Each experimental period lasted 14 d: 10 d for acclimatization to the diets, 2 d for fecal collection, and 2 d for digesta collection. Diets, fecal, and ileal digesta samples were analyzed for gross energy (GE), crude protein (CP), fiber composition, amino acids (AA), and titanium. The concentration of short-chain fatty acids and ammonia were analyzed in digesta and fecal samples. Orthogonal polynomial contrasts were used to determine the linear and quadratic effects of increasing levels of isoacids. Dietary supplementation of isoacids improved (P < 0.1, linear and/or quadratic) AID of crude fiber and hemicellulose and most of the indispensable AA (except Met+Cys, Trp, and Val) as well as ATTD of CP, GE, neutral detergent fiber, and hemicellulose. In addition, ATTD of Arg, His, Ile, Leu, Met+Cys, Phe, Thr, Trp, and Val increased quadratically (P < 0.1). Collectively, 1% isoacid inclusion promoted the greatest responses in most measured variables (% increase: unsupplemented vs. 1%): AID of Lys (9.3%), Met (5.7%), Thr (17.8%), Leu (7.4%), Ile (9.2%), Phe (7.8%), His (5.9%), Arg (4.9%); ATTD of CP (2.1%), GE (1.3%), NDF (3.9%), hemicellulose (>50%), overall indispensable AA (9.5%), overall dispensable AA (8.6%). On the other hand, the inclusion of isoacids quadratically increased (P = 0.071) the concentration of ammonia and decreased (P < 0.1) the concentration of acetic acid, iso-valeric acid, and total VFA in ileal digesta samples. In fecal samples, the proportion of acetic acid decreased (P < 0.05) quadratically while the proportion of propionic, valeric, and caproic acids increased (P < 0.1). In conclusion, dietary supplementation of isoacids at 1% can improve dietary nutrient digestibility, particularly ileal AA digestibility. Based on the changes in fermentation products, the modulation of intestinal microbiota through the gastrointestinal tract could be potentially related to the effects of isoacids on nutrient digestibility. However, the effects of isoacids supplementation on intestinal microbiota must be determined.

Effects of extrusion on ileal and total tract digestibility of nutrients and energy in soybean for weanling pigs

This study evaluated the ileal and total tract digestibility of nutrients and energy in soybean extruded at three different conditions, compared to deactivated soybean (DS), in newly weaned piglets. Forty crossbred barrows (28 d old and 7.64 ± 0.88 kg body weight) were allotted to 5 dietary treatments with 8 replications per treatment. The diets consisted of an N-free diet, to determine endogenous losses of amino acids (AA), and 4 diets containing 30% of test ingredients as the only source of protein and AA: soybean extruded at 82 °C (SB82), 122 °C (SB122) and 137 °C (SB137), and DS, which was used as a control. The DS was produced by heating the whole raw soybean, from 63 °C to 107 °C under pressure. Titanium dioxide was added to the diets as an indigestible marker. After a 5 d adaptation period, partial feces collection was performed over 5 d and samples of ileal digesta were collected after piglets euthanasia. The apparent total tract digestibility of dry matter, gross energy (GE), crude protein (CP), neutral detergent fiber and acid detergent fiber, and apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of CP and AA were evaluated. Analysis of variance was performed and the means compared by Tukey test when P < 0.05. The extrusion of soybean at 122 °C and 137 °C was effective in reducing trypsin inhibitors content, and promoted adequate nutrient and energy digestibility of soybean in piglets. These effects could be observed as the AID of Lys and Trp, and SID of Lys of SB122 and SB137 were greater (P < 0.05) than those of SB82 and DS. The AID and SID of CP and remaining AA were similar among SB122, SB137 and DS, but greater (P < 0.05) than those of SB82. In addition, the ATTD of GE of SB122 was 3–4% greater (P < 0.05) than those of DS and SB82, showing an important effect of extrusion on energy use by pigs. Thus, extrusion of soybean at 122 °C is recommended and SB122 is a feed ingredient with greater nutritional value than DS or SB82 for young pigs.

Influence of Trans-anethole on the nutrient digestibility and intestinal barrier function in broilers

This experiment was undertaken to investigate the effects of dietary trans-anethole (TA) at 5 levels (0, 200, 400, 600, and 800 mg/kg of diet) on the growth performance, apparent nutrient digestibility and intestinal barrier function in broilers. Three hundred twenty 1-day-old Arbor Acres broilers were randomly divided into the 5 dietary treatments with 8 replicates each for 42 d. Dietary TA supplementation increased (P < 0.05) average daily feed intake (ADFI), but had no effects (P > 0.05) on average daily gain (ADG), feed/gain (F/G), and body weight (BW) of broilers throughout the entire experimental period. The apparent metabolizable energy (AME) and nitrogen-corrected apparent metabolizable energy (AMEn), the apparent total tract digestibility of dry matter (DM), crude protein (CP), organic matter (OM), and gross energy (GE) showed a quadratic increase (P < 0.05) with the increasing TA concentration in the diet. The apparent ileal digestibility of Lys, Met, Leu, Thr, Ala, Tyr, and Pro were higher (P < 0.05) in birds fed TA diets compared with control group. Dietary supplementation of 400 mg/kg of TA increased (P < 0.05) mRNA levels of jejunal and ileal Na+/glucose co-transporter (SGLT1) on d 21 and d 42, oligopeptide transporter 1 (PepT1) on d 42, and ileal mRNA expressions of occludin (OCLN), claudin-1 (CLDN-1), and mucin 2 (MUC2), villus height (VH), crypt depth (CD), and VH:CD on d 21, as well as jejunal zonula-occludens-1 (ZO-1) and ileal mucin 2 on d 42. Linear or quadratic responses of the jejunal CD and villus VH:CD ratio occurred (P < 0.01) with increasing dietary TA concentration on d 42. The inclusion of 400 mg/kg TA decreased (P < 0.05) cecal Escherichia coli population on d 21 and d 42, but increased (P < 0.05) Bifidobacterium population on d 21 and ileal Bifidobacterium on d 42. In conclusion, 400 mg/kg of TA is the optimum concentration for increasing nutrient utilization and intestinal barrier function of broilers.

Effect of high concentration of phytase supplementation on energy and nutrient digestibility of growing pigs fed with reduced dietary crude protein balanced with limiting amino acids

There is a need to improve pig production at least cost through various dietary manipulations and nutrient management strategies that will foster reduced environmental wastes of N, amino acids (AA), P, and Ca. This experiment was designed to estimate the effect of phytase supplementation on energy and nutrient digestibility of growing pigs fed with reduced dietary crude protein (CP) balanced with limiting AA. Experimental diets were formulated in a 3 × 2 factorial arrangement of 6 dietary treatments containing 3 CP concentrations (14, 16, and 18%) supplemented with or without 5,000 units phytase/g. Limiting AA of the diets were balanced using crystalline Lys, Met, Thr, and Trp. The 6 experimental diets were fed to 6 cannulated growing pigs (30.00 ± 2.10 kg) in a 6 × 6 Latin square arrangement of 6 diets and 6 periods. Fecal and ileal samples were collected to estimate the apparent and ileal digestibility of nutrients and energy. Apparent total tract digestibility (ATTD) of dry matter (DM), N, crude fibre, ether extract, and energy decreased (P< 0.05) linearly as CP concentration increased in the diets. Apparent ileal digestibility (AID) and ATTD of N linearly decreased (P = 0.000) by increasing CP concentration in the diets from 14 to 18%. Increasing CP concentration linearly increased ATTD (P = 0.002) and AID (P = 0.003) of P. Greater ATTD and (AID) (P< 0.001) of nutrients and energy were observed with pigs fed diets supplemented with phytase. Apparent ileal digestibility of Lys, Met, Thr, Trp, and Glu decreased linearly and quadratically (P< 0.005) while, AID of Arg, His, Iso, Leu, Phe, Val, Ala, Asp, Cys, Gly, Pro, Ser and Tyr improved (P = 0.000) linearly and quadratically as dietary CP increased from 14 to 18% CP. Dietary supplementation with phytase improved (P< 0.001) AID of all the essential amino acids. Arg, His, Ile, Leu, Asp, and Pro were not affected by CP and phytase interaction. Greater (P< 0.001) AID values were observed for all AA following phytase supplementation. It was concluded from the present study that 2 and 4% reduction in dietary CP balanced with Lys. Met, Thr, and Trp resulted in improved ATTD and AID of DM, N and AID of the supplemented AA in growing pigs. Pigs fed diets supplemented with phytase had better ATTD and AID of nutrients and energy than those fed without phytase supplementation.

Impact of increasing the levels of insoluble fiber and on the method of diet formulation measures of energy and nutrient digestibility in growing pigs.

The objective of this study was to determine the differences in response to distillers dried grains with solubles (DDGS) level under constant nutrient or floating nutrient concentrations. A total of 21 ileal-cannulated gilts (33.1 ± 0.4 kg body weight) were randomly allotted to one of seven dietary treatments in a 3-period incomplete Latin square design (n = 9). Treatments consisted of a 0% DDGS basal diet, plus diets containing 15%, 30%, or 45% DDGS. Diets were formulated using one of two different formulation methods: 1) constant nutrient (CNU) where nutrients were held equal to the basal diet or 2) constant ingredients (CIN) where DDGS were added at the expense of corn and all other ingredients remained constant, so nutrient levels were allowed to “float.” Chromic oxide was added to the diets at 0.5% as an indigestible marker. Increasing the level of DDGS decreased the apparent ileal digestibility (AID) of dry matter (DM), gross energy (GE), starch, dispensable amino acids (AA), and fiber components (P < 0.050). The decrease in the AID of Lys, Met, Thr, and Trp was more pronounced under CNU compared with the CIN formulation method (P < 0.050). The decrease in the AID of hemicellulose was less pronounced under CNU compared with the CIN formulation method (P = 0.045). There was a DDGS level × formulation method interaction for the AID of acid hydrolyzed ether extract (AEE; P = 0.015); for the CNU formulation method, increasing level of DDGS decreased the AID of AEE from 0% to 30% and remained similar from 30% to 45% DDGS, whereas the CIN had no effect on the AID of AEE. Increasing the level of DDGS decreased the apparent total tract digestibility (ATTD) of DM, GE, and fiber components (P < 0.050), except for acid detergent fiber, which was not affected. The decrease in the ATTD of insoluble dietary fiber and total dietary fiber was less pronounced under CNU compared with CIN (P < 0.050). The ATTD of AEE decreased for CNU compared with CIN (P < 0.010). In conclusion, increasing the insoluble fiber level in the form of DDGS decreased the digestibility of most dietary components, including DM, GE, starch, insoluble fiber, and AA. The CNU and CIN formulation methods are equivalent when evaluating the digestibilities of DM, GE, starch, crude protein, and AA (when they were not added in purified synthetic forms). Differences between CNU and CIN formulation methods were detected for the digestibility of insoluble fiber, fat, and essential AA (when added as crystalline AA).

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±1.9kg), 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.

Comparison of amino acid digestibility in full-fat soybean, two soybean meals, and peanut flour between broiler chickens and growing pigs.

The aim of this study was to determine the apparent ileal digestibility (AID) and the standardized ileal digestibility (SID) of CP and AA in full-fat soybean (FFSB), solvent-extracted soybean meal containing 430 g/kg CP (SBM-43), solvent-extracted soybean meal containing 470 g/kg CP (SBM-47), and peanut flour (PNF) fed to broiler chickens and pigs and to compare the digestibility of CP and AA between broiler chickens and pigs. Four diets were prepared to contain FFSB, SBM-43, SBM-47, and PNF as the sole source of N. A N-free diet was formulated to estimate the basal ileal endogenous losses of CP and AA for broiler chickens and pigs. In Exp. 1, a total of four hundred sixteen 21-d-old male broiler chickens (922.1 ± 79.9 g initial BW) were assigned to 5 experimental diets in a randomized complete block design with BW as a blocking factor. After 5 d of adaptation, ileal digesta samples were collected after birds were euthanized by CO asphyxiation. In Exp. 2, twenty barrows (62.0 ± 6.9 kg initial BW) surgically fitted with T-cannulas at the distal ileum were allotted to 5 experimental diets with 2 consecutive 7-d experimental periods. After 5 d of adaptation, ileal digesta samples were collected at d 6 and 7. For statistical analysis, treatments were considered a 2 × 4 factorial arrangement with effects of species and experimental diets (Exp. 1 vs. Exp. 2). There were no interactions between species and diets for the digestibility of CP and AA except for Cys ( < 0.01). The AID of CP and indispensable AA in pigs were greater ( < 0.01) than in broiler chickens. In both broiler chickens and pigs, the AID of CP and indispensable AA in SBM-47 were greater ( < 0.05) than in FFSB, and the AID of Lys in PNF was the least ( < 0.05) among ingredients. The SID of CP and indispensable AA in pigs were greater ( < 0.05) than in broiler chickens except for Trp. In both broiler chickens and pigs, the SID of Lys in PNF was the least ( < 0.05) among ingredients. In broiler chickens, the SID of CP, Ile, Leu, Thr, Trp, and Val in FFSB were less ( < 0.05) than that in SBM-43, SBM-47, and PNF. In pigs, the SID of Arg, Ile, Leu, Met, Phe, and Val in FFSB were less ( < 0.05) than in SBM-43, SBM-47, and PNF. In conclusion, the digestibility of CP and most AA were less in broiler chickens than in pigs, but the pattern of differences in the AA digestibility among ingredients was similar between broiler chickens and pigs.

Comparative ileal amino acid digestibility of distillers' grains for growing pigs.

The objective of the experiment reported here was to investigate and compare the amino acid (AA) digestibility of distillers' dried grains (DDG), distillers' dried grains with solubles (DDGS), high protein distillers' dried grains (HP-DDG), and high protein distillers' dried grains with solubles (HP-DDGS) in growing pigs. Five semi-purified diets consisting of DDG, DDGS, HP-DDG, HP-DDGS, and nitrogen-free diet (NFD) were fed to pigs fitted with simple T-cannula for 5 observations per diet. Endogenous losses of AA at the terminal ileum of pigs that received the NFD were used to calculate standardized ileal digestibility (SID) of AA from apparent ileal digestibility (AID) of AA. The AID of Lys in DDGS was lower (P < 0.05) than that in DDG, which was also lower (P < 0.05) than that in HP-DDG. There were no differences in AID of Met among DDG, DDGS and HP-DDGS, but was greater (P < 0.05) in HP-DDG than in DDG or DDGS. The AID of Thr in HP-DDG was greater (P < 0.05) than that in DDGS but not different from that in DDG or HP-DDGS. The branched-chain AA Ile and Leu had greater (P < 0.05) AID in HP-DDG than in DDG, DDGS or HP-DDGS, and there was no difference among DDG, DDGS, and HP-DDGS. The AID of Trp in DDG and DDGS or HP-DDG and HP-DDGS were not different, but the AID of Trp in HP-DDGS was greater (P < 0.05) than that of DDGS. The greatest SID of the indispensable AA was in HP-DDG. Except for Arg and Lys in which DDG had greater (P < 0.05) digestibility, there was no difference between DDG and DDGS in the SID of the indispensable AA. The SID of Lys in DDG was greater (P < 0.05) than that of DDGS but there was no difference between that of DDG and HP-DDGS. Only His, Ile, and Met had lower (P < 0.05) SID in HP-DDGS than HP-DDG within the indispensable AA. The SID of Ala, Asp, Cys, Glu, Gly, Ser and Tyr were lower (P < 0.05) in DDGS than in HP-DDG. There SID of dispensable AA in DDG was not different from that of HP-DDGS. The current study provided apparent and standardized ileal amino acids digestibility values for traditional and high-protein corn distillers' dried grains coproducts for use in formulating swine diets. Amino acid digestibility was generally higher in HP-DDG than in other tested co-products of the dry grind processing of corn for ethanol.

Effects of dietary deoxynivalenol and zearalenone on apparent ileal digestibility of amino acids in growing pigs

This experiment was conducted to investigate the effects of deoxynivalenol (DON) and zearalenone (ZON) on the apparent ileal digestibility (AID) of AA in growing pigs. Twelve pigs (initial mean body weight=20.6±2.1kg) cannulated at the distal ileum were assigned to 3 dietary treatments in a quadruplicated 3×2 incomplete Latin square design with 3 diets and 2 periods. Three experimental diets consisted of a corn-soybean meal-based control diet, a DON-supplemented diet at 10mg/kg and a ZON-supplemented diet at 10mg/kg. All diets contained 5g/kg chromic oxide as an indigestible index. Each experimental period was comprised of a 5-d adaptation period and a 3-d ileal digesta collection period. The concentration of DON or ZON in the mycotoxin-supplemented diet was analyzed to be 11.2mg/kg or 11.6mg/kg, respectively. Pigs fed the DON-supplemented diet had less AID of Lys (0.799 vs. 0.839, P=0.08), Thr (0.695 vs. 0.751, P=0.08), Trp (0.766 vs. 0.840, P=0.02), and Val (0.687 vs. 0.749, P=0.08) than those fed the control diet, but the AID of other AA were not affected by DON supplementation. With the exception of Trp (0.771 vs. 0.840, P=0.04), the supplementation of ZON to the control diet did not affect the AID of AA. In conclusion, dietary DON, but not ZON, may reduce the AID of some indispensable AA.

Interaction of dietary energy and protein on growth performance, carcass characteristics and digestibility in finishing barrows when fed at a constant digestible lysine to metabolizable energy ratio

The objective of this study was to determine the performance response to changes in dietary fat, protein, and fiber content in finishing barrows while maintaining a constant apparent ileal digestible (AID) Lys to metabolizable energy (ME) ratio (AID Lys:ME). The experiment was conducted in 2 trials, each containing 25 individually penned pigs. In both trials, barrows (initial wt=85.3kg) were blocked by weight and assigned to one of five experimental diets (0.40, 0.44, 0.48, 0.52, and 0.56% digestible Lys) with a constant AID Lys:ME (1.44g/MCal). Lysine content was changed by altering the proportions of corn and soybean meal and energy was altered by the addition or removal of cellulose and fat. Diets contained 0.2% titanium dioxide as a digestibility marker. Pigs were fed experimental diets for 28d, and body weights, feed intakes, and ultrasound measurements of tenth rib backfat (BF) and loin eye area (LEA) were recorded on d 14 and 28. Blood samples were taken on d 28 to determine serum urea nitrogen (SUN), insulin, T3, and T4. A quadratic effect of increasing dietary Lys was seen on ADG on d 28 showing that the addition of Lys increased gain (P<0.01). Additionally, feed efficiency, energy intake, and Lys intake increased linearly as dietary Lys concentration increased from 0.40% to 0.56% AID Lys (P<0.01). Levels of T3 increased with increasing Lys (P<0.01), but there was no effect of diet on SUN, T4, or insulin. Ultrasound estimates of BF and LEA tended to increase linearly and quadratically, respectively, as dietary Lys increased (P<0.10). Digestibility of energy, protein, NDF, and hemicellulose increased linearly in pigs fed 0.40–0.56% AID Lys (P<0.05). These results demonstrate that formulating diets to meet the recommended AID Lys:ME is not sufficient to ensure optimal growth. Therefore, the concentration of protein and energy of the diet must be individually evaluated and corrected to obtain optimal growth and efficiency.

Optimal lysine:DE ratio in growing pigs is independent of starch or fat as main energy source at two energy intake levels1

In a 2 × 2 factorial arrangement, 28 growing boars (initial BW of 24.7 ± 1.5 kg) were used to examine the effects of energy source (high starch vs. high fat) and DE level (2.2 vs. 2.7 times the DE requirements for maintenance) on Lys requirements. Pigs were allotted to 1 of 4 dietary treatments. A within-animal Lys titration technique was used to assess the responses to changes in Lys to energy ratio. The amount of apparent ileal digestible Lys in the diet decreased stepwise from 1.74 to 0.5 g/MJ DE in 8 equidistant steps of 3 d each. From 48-h urinary nitrogen excretion, the optimal Lys to energy ratio was estimated for each pig using a linear-plateau model. Feces were collected quantitatively over 27 d to determine apparent total tract digestibility (ATTD) of nutrients. The DE to ADG ratio, but not DE intake and ADG, tended ( < 0.1) to be 4% lower in the high-starch group than in the high-fat group. The ATTD of energy and CP tended ( < 0.1) to be lower (0.8% and 0.9% units, respectively) at the high DE level. The ATTD of energy was 2.2% units greater ( < 0.001) for pigs fed the high-starch diet, but the ATTD of CP was not affected by ES. Estimates for the intercept (21.2% to 22.8%), slope (57.4 to 59.6), transition point (0.84 to 0.86 g Lys/MJ DE), and plateau (70.6% to 72.3%) of the linear-plateau Lys titration curves were not affected by the dietary treatments. In conclusion, ES does not affect Lys requirements in growing pigs regardless the level of DE intake.

Ileal digestibility of amino acids in meat meal and soybean meal fed to growing pigs.

The objective of this experiment was to determine the concentration and digestibility of crude protein (CP) and amino acid (AA) in meat meal (MM), and to compare these values with the respective values in soybean meal (SBM). Six barrows (initial body weight = 66.9±3.8 kg) surgically fitted with a T-cannula at the distal ileum were allotted to a replicated 3×3 balanced Latin square design with 3 diets and 3 periods. Two experimental diets containing test ingredients as the sole source of AA were prepared to estimate the apparent ileal digestibility (AID) for CP and AA by the direct method. An N-free diet was also prepared to estimate basal endogenous losses of CP and AA. All experimental diets contained 5% chromic oxide as an indigestible index. Each period consisted of a 5-d adaptation period and a 2-d of ileal digesta collection period. Ileal digesta samples were collected from 0900 to 1700 on d 6 and 7 of each period. The concentrations of CP, Lys, Met, and Trp in MM and SBM were analyzed to be 64.1, 3.5, 1.1 and 0.6, and 45.6, 2.8, 0.8, and 0.3%, respectively. The AID of all AA except Gly in MM was less (p<0.05) than in SBM. The AID of Lys, Met, and Trp in MM was estimated to be 56.0, 71.7, and 47.1%, respectively. The SID of all AA in MM was less (p<0.05) than in SBM. The SID of Lys, Met, and Trp was 65.1, 79.2, and 78.5%, respectively. In conclusion, the CP and AA contents in MM were greater than those in SBM whereas the ileal digestibility of all AA in MM was less than in SBM.

Influence of feed form and source of soybean meal on growth performance, nutrient retention, and digestive organ size of broilers. 2. Battery study

Two experiments were conducted to determine the apparent ileal digestibility (AID) of the amino acids (AA) of 4 commercial soybean meals (SBM) from the United States (USA-1, 48.1% CP and USA-2, 46.2% CP), Brazil (BRA, 47.6% CP), and Argentina (ARG, 46.3% CP) and the effects of the inclusion of these SBM in diets in mash, crumble, or pellet form on growth performance, total tract apparent retention of nutrients, and digestive organ size in broilers reared in cages from 1 to 25 d of age. In experiment 1, the AID of Lys was higher (P < 0.05) for the USA-2 than for the BRA SBM, with the SBM from USA-1 and ARG being intermediate. In experiment 2, 12 diets were arranged as a 3 × 4 factorial with 3 feed forms (mash, crumbles, and pellets) and the 4 sources of SBM used in experiment 1. The feeds were isonutritive and the AID of the AA of the SBM obtained in experiment 1 was used for diet formulation. Broilers fed mash had lower (P < 0.001) ADFI and ADG and poorer (P < 0.001) feed-to-gain ratio than broilers fed crumbles or pellets but source of SBM did not affect growth performance. Nitrogen retention was higher (P < 0.01) in birds fed mash than in birds fed crumbles or pellets at all ages. The total tract apparent retention of nutrients was lower (P < 0.05) for the BRA and ARG SBM diets than for the USA-1 and USA-2 SBM diets. Gizzard empty relative weight (% BW) was higher and gizzard pH lower for broilers fed mash than for broilers fed crumbles or pellets (P < 0.001). The results indicate that crumbling or pelleting of the diets improved growth performance of broilers from 1 to 25 d of age. Diets formulated with analyzed rather than calculated AID of AA of the SBM sources resulted in similar broiler performance.

Dietary protein excess does not influence calcium and phosphorus absorption and retention in Iberian pigs growing from 50 to 100 kg body weight1

Effects of apparent total tract digestible dietary protein [expressed as apparent ileal digestible (AID) Lys in parentheses] from excessive to marginally deficient [110 (7.9), 92 (6.6), 73 (5.3) and 54 (3.8) g/kg DM] and feeding level (FL; 0.80 and 0.95 × ad libitum) upon fractional absorption and retention of Ca and P was studied in 48 purebred Iberian barrows from 50 to 100 kg BW to investigate possible detrimental effects of protein over supply on Ca and P metabolism. The diets were prepared by diluting a high-protein diet, formulated according to the ideal protein concept, with a protein-free mixture. The diets provided (per kg DM) 11.6 to 10.7 g Ca, 6.67 to 6.25 g total P, and 13.9 to 14.8 MJ ME. Intake levels with free access to feed were calculated according to individual BW and were adjusted weekly. A digestibility and balance trial was performed at 75 kg BW. The ADFI was 3104 and 2643 g for 0.95 and 0.80 × ad libitum FL. The ADG reached a maximum at 854 g (18.87 g/MJ ME intake) with the diet containing 5.3 g AID Lys/kg DM. Dietary AID Lys content did not alter Ca and P fractional apparent absorption, which attained average values of 0.417 ± 0.0109 and 0.545 ± 0.0106. The Ca and P retention as a fraction of intake remained unaffected at 0.403 ± 0.0114 and 0.403 ± 0.0120. The Ca urinary losses were not elevated by excess of dietary protein supply, remaining at 0.260 ± 0.0212 g/d. High feeding level increased (P < 0.05) the flow of absorbed Ca and P. In conclusion, long-term, high-protein (Lys) intake did not affect Ca intestinal absorption and renal excretion in the pig.

Effect of increasing dried blood cells in corn-soybean meal diets on growth performance of weanling and growing pigs

Dried blood cells (DBC) contain low levels of Ile relative to Lys, and thus Ile may become limiting in pig diets supplemented with DBC. Therefore, 3 experiments were conducted to evaluate the effect of increasing DBC in corn-soybean meal–based diets in weanling (7 to 13 kg, Exp. 1 and 2) and grower (24 to 46 kg, Exp. 3) pigs. Treatments were replicated with 4 to 6 pens of 4 to 6 pigs per pen. In Exp. 1 and 2 (14 d), all diets contained 0.10% l-Lys·HCl and DBC were added at 2% increments from 0 to 8%. In Exp. 1, all diets contained 1.40% total dietary Lys. All diets in Exp. 2 contained 1.185% apparent ileal digestible Lys. In Exp. 1, increasing dietary DBC resulted in a linear decrease in ADFI (P 0.10). In Exp. 2, increasing dietary DBC resulted in a decrease in ADG (linear and quadratic, P < 0.01) and a linear decrease in ADFI and G:F (P < 0.05). Experiment 3 was conducted for 28 d to determine the effect of graded levels of DBC. In Exp. 3, DBC were added to the diets at 2% increments from 0 to 8%. All diets contained 1.00% total dietary Lys. In Exp. 3, increasing dietary DBC resulted in a decrease in ADG and ADFI (linear, P < 0.01). Feed efficiency was not significantly affected by the increasing levels of DBC. The results of these 3 experiments indicate that ADG can be maintained with up to 4% DBC, but DBC fed above 2% may have a negative effect on feed efficiency of weanling and grower pigs. The maximum inclusion level of DBC that can be added in a diet for weanling and growing pigs without reducing growth performance is dependent on the Ile:Lys.

ORIGINAL ARTICLE: Effects of herbage ingestion upon ileal digestibility of amino acids in heavy Iberian pigs fed on an acorn-based diet

We conducted two experiments with heavy Iberian pigs to determine the ileal digestibility of amino acids (AA) in acorns and freshly cut herbage, and the effects of adding fresh herbage upon the supply of ileal digestible AA when pigs were fed on holm-oak acorns. In Experiment 1, carried out in cannulated pigs of 107 kg bodyweight (BW), daily intake of acorns reached 44.9 g DM/kg(0.75) BW. Arg, His and Thr showed the lowest apparent ileal digestibility (AID) values, whereas Met, the branched-chain AA and Phe had the highest coefficients. The AID of total EAA was 0.716 but only 0.222 for NEAA. Most of the digestive and absorptive processes of acorn protein occurred before the hindgut. Acorn provides (per kg DM) 2.27 g apparent ileal digestible Lys and 22.7 g apparent total digestible AA. Standardized ileal digestibility (SID) values for EAA, NEAA and total AA were 0.924 ± 0.020, 0.784 ± 0.041 and 0.860 ± 0.029. In Experiment 2 fresh herbage was given to six cannulated Iberian pigs of 140 kg either as a single feed (13.7 g DM/kg(0.75) BW) or as a supplement to acorns (28.4 g DM/kg(0.75) BW). When only freshly cut forage was offered the AID of the EAA, NEAA and total AA was close to 0.65 and supplied (per kg DM ingested) 5.61 g AID Lys and 91.7 g digestible AA. Standardized ileal values were 0.744 ± 0.023, 0.912 ± 0.038 and 0.831 ± 0.030 respectively. The addition of fresh forage to the acorns led to a significant decrease in AID of AA in acorn due to digesta transfer to the hindgut: His (p < 0.01), Met (p < 0.001), Phe (p = 0.092), Thr (p < 0.05) and Val (p < 0.05), but Arg, Lys and the branched-chain AA remained unaffected. The main contribution of herbage to AA nutrition of the grazing Iberian pig relies mainly on increasing the supply of digestible AA for pig tissues.

Effects of distillers dried grains with solubles on amino acid, energy, and fiber digestibility and on hindgut fermentation of dietary fiber in a corn-soybean meal diet fed to growing pigs

The objective of this experiment was to measure the effect of distillers dried grains with solubles (DDGS) on the digestibility of AA, energy, and fiber, on the fermentation of fiber, and on the first appearance of digesta at the end of the ileum, in the cecum, and in the feces of growing pigs fed a corn-soybean meal-based diet. Sixteen pigs (initial BW = 38.0 +/- 1.6 kg) were prepared with a T-cannula in the distal ileum and a T-cannula in the cecum and allotted to 2 treatments. In period 1, all pigs were fed a corn-soybean meal diet. In periods 2, 3, and 4, pigs were fed the control diet or a diet containing corn, soybean meal, and 30% DDGS. First appearance of digesta at the end of the ileum, in the cecum, and over the entire intestinal tract was measured at the end of period 4. The apparent ileal digestibility (AID) and the apparent total tract digestibility (ATTD) of nutrients were measured, and the concentration of VFA was analyzed in ileal, cecal, and fecal samples. The AID of Lys (74.1%) in the DDGS diet was less (P < 0.05) than in the control diet (78.6%), but the AID of most other AA and GE, NDF, and total dietary fiber (TDF) were not different between the 2 diets. The ATTD of GE (81.0%), NDF (57.2%), TDF (55.5%), and DM (81.7%) were less (P < 0.05) in the DDGS diet than in the control diet (86.0, 69.3, 66.0, and 87.2%, respectively). The concentration of VFA in ileal, cecal, and fecal samples was not different between pigs fed the 2 diets. The pH of ileal and cecal digesta from pigs fed the DDGS diet (6.3 and 5.5) was greater (P < 0.01) than from pigs fed the control diet (5.8 and 5.3). The ATTD of DM, GE, ADF, NDF, and TDF did not change with collection period, but the AID of ADF, NDF, and TDF increased (P < 0.05) from period 2 to period 4. The concentration of all VFA, except isobutyrate, was greater (P < 0.05) in cecal samples from period 4 compared with period 2, and the concentration of all VFA except propionate and isovalerate were greater (P < 0.05) in fecal samples collected in period 4 compared with those collected in period 2. The first appearance of digesta at the end of the ileum, in the cecum, and in the feces was not affected by DDGS. In conclusion, pigs fed the diet containing DDGS had less digestibility of Lys, GE, ADF, NDF, and TDF than pigs fed the control diet. The digestibility of DM and GE was not influenced by collection period, but the concentration of VFA in cecal digesta and feces increased with the length of time pigs received the diets.

Effect of incremental levels of red blood cells on growth performance and carcass traits of finishing pigs1,2

Three experiments were conducted to determine the effect of incremental levels of red blood cells (RBC; 0 to 4%, Exp. 1; 0 to 2%, Exp. 2 and 3) on growth performance and carcass traits of finishing pigs. Dietary treatments were formulated to meet or exceed the nutrient requirements of barrows and gilts gaining 350 g of lean BW gain per day and were formulated to contain 0.52% apparent ileal digestible (AID) Lys for barrows and 0.59% AID Lys for gilts. In Exp. 1, barrows and gilts (2 replicates of barrows and 2 of gilts; 4 pigs per pen) were fed 0, 1, 2, 3, or 4% RBC. Initial BW (mean +/- SD) was 84.6 +/- 4.9 and 82.42 +/- 4.8 kg, and final BW was 118.7 +/- 6.5 and 120.0 +/- 9.6 kg for barrows and gilts, respectively. Two barrows and 2 gilts per pen were randomly selected and slaughtered for collection of carcass measurements. Experiment 2 was similar to Exp. 1, except 0, 1, or 2% RBC were added. Initial BW was 82.5 +/- 6.4 and 79.2 +/- 7.0 kg, and final BW was 125.5 +/- 6.2 and 119.8 +/- 8.8 kg for barrows and gilts, respectively. Each dietary treatment had 4 replicates per sex with 4 pigs per pen. One barrow and 1 gilt per treatment replicate were randomly selected and slaughtered for collection of carcass traits and viscera weights. Experiment 3 was similar to Exp. 2 except only barrows were used, and the initial and final BW were 86.0 +/- 5.7 and 133.4 +/- 8.4 kg, respectively. Each dietary treatment had 4 replicates with 3 pigs per pen, and all pigs were slaughtered for collection of carcass traits and viscera weights. In Exp. 1, final BW, ADG, and G:F were decreased linearly (P < 0.01 to 0.10) as RBC addition increased, but ADFI was not affected. With increased RBC addition, average backfat increased (P < 0.09) and fat free lean decreased (P < 0.04). There was a quadratic effect (P < 0.04) on dressing percentage (DP); the 2% RBC addition increased DP, but the 3 and 4% additions decreased DP. The RBC addition had no effect (P > 0.10) on any remaining carcass measurements. In Exp. 2, there was a quadratic effect (P < 0.07) of RBC addition on average backfat; the 1% RBC addition decreased backfat, but the 2% addition returned backfat to the level of the control pigs. There was no effect (P > 0.10) on any other response variable. In Exp. 3, with increased RBC addition, average backfat linearly decreased (P < 0.04) and large intestine percentage increased (P < 0.09). There was no effect of RBC addition (P > 0.10) on any other response variable. Our data indicate that feeding 3 or 4% RBC decreases growth performance of finishing pigs. However, feeding 1 or 2% RBC to finishing pigs had no detrimental effects on growth performance and increased DP in one experiment.

Amino acid digestibility of distillers dried grains with solubles, produced from sorghum, a sorghum-corn blend, and corn fed to growing pigs1,2

The objective of this experiment was to measure the concentration and digestibility of CP and AA in distillers dried grains with solubles (DDGS) produced from sorghum (S-DDGS) or a blend of sorghum and corn grains (SC-DDGS), and to compare these values with the digestibility of CP and AA in corn-based DDGS (C-DDGS). Eleven growing barrows (initial BW = 44.6 +/- 6.5 kg) were surgically fitted with a T-cannula in the distal ileum and allotted to a Youden square design with 11 diets and 8 periods. One diet contained 66.7% S-DDGS, 1 diet contained 66.7% SC-DDGS, 8 diets contained 66.7% C-DDGS, and 1 diet was N-free. Chromic oxide (0.3%) was used in all diets as an indigestible marker. The direct procedure was used to measure apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of CP and AA in the 10 sources of DDGS. Results of the experiment showed that the AID of Lys was not different among S-DDGS, SC-DDGS, and C-DDGS. The mean SID of CP, Arg, and Lys in C-DDGS were not different from values obtained in S-DDGS and SC-DDGS. The SID of Trp in S-DDGS (72.0%) was greater (P < 0.01) than in C-DDGS (64.9%), but there was no difference between C-DDGS and SC-DDGS (62.4%). The SID of CP and all AA were different among the 8 sources of C-DDGS (P < 0.01). Among the indispensable AA, Lys had the greatest variation and the SID ranged from 55.7 to 68.7%. The concentration of total and digestible AA was highly correlated (r(2)) for Arg (0.88), Ile (0.85), Leu (0.82), Phe (0.84), and Trp (0.84), but reduced r(2) values were observed for Lys (0.66) and Thr (0.39). A low correlation between the concentration and digestibility of AA indicates that it is desirable to develop in vitro procedures to predict digestible AA concentration in DDGS. In conclusion, SID values for CP and Lys in S-DDGS and SC-DDGS are within the range of values obtained in C-DDGS, but for many other AA, SID values in S-DDGS and in SC-DDGS are less than in C-DDGS.

Nutrient digestibility and performance responses of growing pigs fed phytase- and xylanase-supplemented wheat-based diets1

Three experiments were conducted to evaluate the effect of supplementing phytase and xylanase on nutrient digestibility and performance of growing pigs fed wheat-based diets. In Exp. 1, 10 diets were fed to 60 pigs from 20 to 60 kg of BW to determine the effect of combining phytase and xylanase on apparent total tract digestibility (ATTD) of nutrients and growth performance. The 10 diets included a positive control diet (PC; 0.23% available P; 0.60% Ca) and a negative control diet (NC; 0.16% available P; 0.50% Ca) supplemented with phytase at 0, 250, and 500 fytase units (FTU)/kg and xylanase at 0, 2,000, and 4,000 xylanase units (XU)/kg in a 3 x 3 factorial arrangement. In Exp. 2, 6 ileally cannulated barrows (initial BW = 35.1 kg) were fed 4 wheat-based diets in a 4 x 4 Latin square design, with 2 added columns to determine the effect of combining phytase and xylanase on apparent ileal digestibility (AID) of nutrients. The 4 diets were NC (same as that used in Exp. 1) or NC supplemented with phytase at 500 FTU/kg, xylanase at 4,000 XU/kg, or phytase at 500 FTU/kg plus xylanase at 4,000 XU/kg. In Exp. 3, 36 barrows (initial BW = 55.5 kg) were fed 4 diets based on prepelleted (at 80 degrees C) and crumpled wheat for 2 wk to determine the effect of phytase supplementation on ATTD of nutrients. The 4 diets fed were a PC (0.22% available P; 0.54% Ca) and a NC (0.13% available P; 0.43% Ca) alone or with phytase at 500 or 1,000 FTU/kg. All diets in the 3 experiments contained Cr(2)O(3) as an indigestible marker. No synergistic interactions were detected between phytase and xylanase on any of the response criteria measured in Exp. 1 or 2. There were no dietary effects on growth performance in Exp. 1. In Exp. 1, phytase at 250 FTU/kg increased the ATTD of P and Ca by 51 and 11% at 20 kg of BW or by 54 and 10% at 60 kg of BW, respectively, but increasing the level of phytase to 500 FTU/kg only increased (P < 0.05) ATTD of P at 20 kg of BW. In Exp. 2, phytase at 500 FTU/kg increased (P < 0.05) the AID of P and Ca by 21 and 12%, respectively. In Exp. 3, phytase at 500 FTU/kg improved (P < 0.05) ATTD of P by 36%, but had no further effect at 1,000 FTU/kg. Xylanase at 4,000 XU/kg improved (P < 0.05) AID of Lys, Leu, Phe, Thr, Gly, and Ser in Exp. 2. In conclusion, phytase and xylanase improved P and AA digestibilities, respectively, but no interaction between the 2 enzymes was noted.