Effect of micronized pea and enzyme supplementation on nutrient utilization and manure output in growing pigs

An experiment was done to determine manure output, N and P excretion, and apparent digestibilities of AA, CP, P, and DM in growing pigs fed barley-based diets containing micronized or raw peas with or without supplementation with enzyme containing primarily beta-glucanase and phytase (Biogal S+). Eight barrows (21.5 +/- 1.2 kg of initial BW) fitted with T-cannulas at the distal ileum were used in a 40-d trial and housed in metabolism cages. Pigs were assigned in a replicated 4 x 4 Latin square design to 4 experimental diets: 1) barley-raw peas control (BRP), 2) barley-micronized peas (BMP), 3) BRP plus enzyme, and 4) BMP plus enzyme (BMP+E). Pigs received 2.6 times maintenance energy requirements based on BW at the beginning of each experimental period. During each experimental period, pigs were acclimatized to their respective diets for 5 d followed by a 3-d period of total fecal and urine collection and another 2-d period of ileal digesta collection. Samples were analyzed for DM, AA (diets and digesta only), N, and P. Wet fecal output of BRP plus enzyme-fed pigs tended to be lower (P = 0.07) than the amount produced by BMP-fed pigs. The amounts of dry feces and urine produced were not different among treatments (P > 0.10). Supplementing the BRP and BMP diet with enzyme increased (P = 0.002) the daily P retained per pig. Pigs fed the enzyme-supplemented diets tended to have lower (P = 0.06) fecal P excretion and greater urinary P excretion (P = 0.001) compared with pigs fed the nonsupplemented diets, but total P excretion was not influenced by diet (P > 0.10). Pigs fed the BMP+E diet retained more (P = 0.006) N per day than pigs fed the BMP diet. However, N excretion was not influenced by dietary treatment (P > 0.10), although BMP+E-fed pigs excreted 13.2% less N in the feces compared with those fed the nonenzyme supplemented controls. Inclusion of micronized peas with or without enzyme supplementation did not affect urinary or fecal N excretion (P > 0.10) compared with the BRP. Dietary treatment had no effect (P > 0.10) on ileal or fecal DM or CP digestibilities. Apparent ileal digestibilities of AA were usually lower (P < 0.05) in the BRP diet compared with the other diets. Enzyme supplementation improved P digestibility at the ileal and fecal level. The current results indicate that utilizing micronized peas in barley-based pig grower diets enhances P retention.     

Real ileal protein and amino acid digestibilities in feedstuffs for growing pigs as determined with the 15N-isotope dilution technique

Twelve gilts, with an average initial BW of 38 kg, were fitted with a simple T-cannula at the distal ileum and two catheters in the external jugular veins. The animals were fed 700 g of one of the experimental diets, twice daily at 0800 and 2000. Diets 1 and 2 were cornstarch-based diets formulated to contain 16% CP from soybean meal and canola meal, respectively. Diets 3 and 4 contained 93.9% wheat and barley, respectively. Chromic oxide was included to determine nutrient digestibilities. Following recovery from surgery, 15N-leucine was infused continuously via a jugular catheter for 9 d at a rate of 40 mg.kg BW-1.d-1. Blood samples were taken at every feeding. Ileal digesta were collected for 24 h on d 7 and 9 of the infusion period. Assuming that the 15N-enrichment excess in the trichloroacetic acid-soluble fraction of the blood was similar to that in endogenous N, the contribution of endogenous to total N in ileal digesta was calculated. The amount of endogenous protein (N x 6.25) recovered in digesta collected from the distal ileum were 25.5, 30.5, 27.4 and 27.7 g/kg DM intake for the pigs fed diets 1, 2, 3 and 4, respectively. In the same order for the diets, the real ileal protein digestibilities were 97.5, 84.1, 99.0 and 94.2%, respectively. In addition, the real ileal amino acid digestibilities were calculated. The recoveries of endogenous protein in ileal digesta and the real ileal protein and amino acid digestibilities were higher than those determined by feeding protein-free diets for determining the recovery of endogenous protein and amino acids in ileal digesta.     

Food intake and ingredient profile affect viscosity of ileal digesta of dogs

Two experiments were conducted to determine dietary factors affecting digesta viscosity. In experiment 1, six ileal-cannulated dogs were either full (607.1 kJ/BW0.67) or restricted (303.5 kJ/BW0.67) fed. In experiment 2, four dog foods were surveyed for effects on digesta viscosity based on protein source [animal protein (AP) or plant protein (PP)] or dietary fibre source [soluble dietary fibre (SDF) or insoluble dietary fibre (IDF)]. Dry matter (DM) intake was higher (p<0.05) when dogs were full (11.4 g/kg) compared with restricted fed (5.98 g/kg). Ileal digesta viscosity tended to be higher (p=0.07) for full fed [10,251 centipoise (cP)] compared with restricted-fed dogs (6677 cP). Ileal digesta viscosities were 6561, 11,074, 13,830 and 15,967 cP for dogs consuming IDF, SDF, AP and PP treatments respectively. Ileal DM concentrations were 11.4%, 13.6%, 14.8% and 14.8% for SDF, IDF, AP and PP treatments respectively. DM digestibility coefficients were lowest (71.2%) for the PP treatment and highest (88.7%) for the IDF treatment. Organic matter digestibilities followed a similar pattern. Ileal digesta viscosity of dogs appears to increase with increased diet intake, and increased ileal DM concentration. More digestible diets result in less ileal DM and lower viscosity constants.     

Growth performance, gastrointestinal microbial activity, and nutrient digestibility in early-weaned pigs fed diets containing flaxseed and carbohydrase enzyme

The effects of ground flaxseed (FS) and a multicarbohydrase enzyme (C) supplement on piglet performance, gastrointestinal microbial activity, and nutrient digestibility were investigated in a 28-d trial. The enzyme supplement provided 500 units of pectinase, 50 units of cellulase, 400 units of mannanase, 1,200 units of xylanase, 450 units of glucanase, and 45 units of galactanase per kilogram of diet. Ninety-six pigs were weaned at 17 d of age (BW, 6.1 +/- 0.4 kg, mean +/- SD) and assigned to treatments based on a 2 x 2 factorial arrangement in a completely randomized design, with 6 pens per diet (4 pigs per pen). The diets contained wheat, barley, peas, soybean meal, and canola meal with 0 or 12% FS, and were fed without or with C. Flaxseed was included by changing the levels of the other ingredients to balance the diets for DE and nutrients. Diets had similar nutrient contents and met the NRC (1998) nutrient specifications, with the exception of DE, CP, and AA, which were 95, 94, and 97% of the NRC requirements, respectively. Diets were fed in a 2-phase feeding program (2 wk/phase). Feed intake and BW were measured weekly, and 1 pig per pen with a BW nearest the pen average was bled weekly to evaluate plasma urea nitrogen. On d 28, fresh fecal samples were collected from each pen and 1 pig per pen with a BW nearest the pen average was killed to evaluate intestinal microbial activity and nutrient digestibility. A dietary effect on piglet performance was observed only in wk 3, when the FS diets decreased (P = 0.005) ADG and G:F, tended to decrease (P = 0.070) ADFI, and increased (P = 0.027) plasma urea nitrogen. An interaction between FS and C was observed for ileal digesta viscosity (P = 0.045), such that C increased viscosity in the FS diet but had no effect in the non-FS diet. Flaxseed and C interacted to affect ileal ammonia content (P = 0.049), such that in the absence of FS, pigs fed the diet with C had lower ammonia than those on the diet without C. Flaxseed and C affected other ileal parameters independently. Pigs fed the FS diets had decreased (P = 0.003 to 0.033) anaerobic spore counts, organic acid, DM, CP, and nonstarch polysaccharide (NSP) digestibility compared with pigs fed the non-FS diets, whereas pigs fed the C-supplemented diets had greater (P = 0.009 to 0.061) lactobacilli counts, lactate, DM, and NSP digestibility than pigs fed the unsupplemented diets. In conclusion, FS reduced ileal microbial activity, nutrient digestibilities, and piglet performance in wk 3. The multicarbohydrase supplement increased ileal DM and NSP digestibilities as well as lactobacilli counts and lactate.     

Diet type affects viscosity of ileal digesta of dogs and simulated gastric and small intestinal digesta

Two experiments were conducted to determine effects of diet type on viscosity of ileal digesta of dogs and simulated gastric and small intestinal digesta. In experiment 1, three canned and three dry dog foods were surveyed for effects on ileal digesta viscosity. Experiment 2 evaluated the same six diets for effects on simulated gastric and small intestinal digesta. Canned diets and dry diets contained an average 22.7% and 89.9% dry matter (DM) respectively. Concentrations of total dietary fibre (TDF) in the diets ranged from 1.8% to 26.5%. Ileal digesta viscosities ranged from 1326 to 46,641 and 7748 to 10,208 cP for canned and dry treatments respectively. Ileal DM concentrations ranged from 8.2% to 16.2% and 15.4% to 15.8% for canned and dry treatments respectively. Dry matter intake ranged from 224 to 290 and 295 to 325 g/day for canned and dry treatments respectively. During gastric digestion simulation, viscosity peaked at 2 and 4 h for all three canned diets and dry diets respectively. During small intestinal digestion simulation, viscosity peaked between 6 and 12 h for most diets except one canned diet and one dry diet, which contained high concentrations of TDF (25.1% and 26.5% respectively). Viscosity of these solutions peaked between 12 and 18 h. Viscosity of ileal digesta and simulated gastric and small intestinal digesta was the lowest after consumption of canned diets with the exception of the canned diet containing very high concentrations of dietary fibre (25.1% TDF). Ileal digesta viscosity of dogs appears to be responsive to the diet type characteristics.     

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

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

Effects of protein and carbohydrate sources on digestibility and digesta flow rate in weaned pigs fed a high-fat, dry diet

Two trials were conducted to evaluate the effects of protein source (48% CP soybean meal or casein) and carbohydrate source (25% dextrose or 25% lactose) on digestibility and digesta flow rate in early-weaned pigs. Diets contained 10% crude soybean oil and were formulated to contain 3.5 g lysine, 2.3 g Ca and 2.0 g P per 1,000 kcal DE of diet. In Trial 1, nutrient digestibility was greater for older than for younger pigs. Apparent digestibilities for energy, DM, CP and fat were lower (P less than .08) for younger and older pigs fed soybean meal rather than casein. Digestibility of soluble carbohydrates was less (P less than .02) for younger pigs fed soybean meal rather than casein as a protein source. Fat digestibility was lower (P less than .05) in younger pigs fed dextrose than in pigs fed lactose. A protein X carbohydrate source interaction (P less than .01) existed for fat digestibility by older pigs. In Trial 2, pigs were euthanatized, and digestibilities anterior to the ileum and the colon (pre-ileal and pre-cecal) were determined. At the ileum, fat digestibility was lower (P less than .05) for pigs fed soybean meal, whereas CP digestibility was lower (P less than .05) for pigs fed either soybean meal or dextrose. A protein X carbohydrate interaction was observed for ileal digestibilities of DM (P less than .06) and total carbohydrates (P less than .03) with lowest values obtained for the soybean meal plus dextrose diet. For casein diets, digestibility values were similar between the two carbohydrate sources.(ABSTRACT TRUNCATED AT 250 WORDS)     

Estimating equivalency values of microbial phytase for amino acids in growing and finishing pigs fitted with steered ileo-cecal valve cannulas

Ten crossbred barrows (48.3 +/- 2.3 kg of initial BW) fitted with steered ileo-cecal valve cannulas were used to investigate the effects of supplemental microbial phytase on the apparent ileal digestibilities (AID) of AA, Ca, P, N, and DM, and the apparent total tract digestibilities of Ca, P, N, and DM. All diets were corn-soybean meal-based, and contained 0.44% Ca and 0.40% total P. Diets 1, 2, and 3 contained 12.0, 11.1, and 10.2% CP, respectively. Diets 4 and 5 had the same ingredient composition as diet 3, plus 250 and 500 U/kg phytase (Natuphos), respectively. Pigs were randomly allotted to 1 of 5 dietary treatments in a paired 5 x 5 Latin square with an extra period to test for carryover effects. Each 14-d period consisted of a 7-d adjustment followed by a 3-d total collection, a 12-h ileal digesta collection, a 3-d readjustment, and a second 12-h ileal digesta collection. Pigs were housed individually in metabolism pens (1.2 x 1.2 m). Water was supplied ad libitum, and feed was supplied at a level of 9% of the metabolic BW (BW(0.75)) per day in 2 equal daily feedings. As the dietary CP concentration increased, the AID of CP and all AA measured increased linearly (P < 0.05) with the exception of proline. In addition, the apparent total tract digestibilities (grams per day) and retention of N (grams per day) increased linearly (P < 0.01) with increasing CP levels. Supplementing diets with phytase increased the AID of Ca (P < 0.01), P (P < 0.001), CP (P = 0.07), and the AA (P < 0.10) Gly, Ala, Val, Ile, Thr, TSAA, Asp, Glu, Phe, Lys, and Arg. Protein and phytase response equations were generated for those AA affected (P < 0.10) by both CP level and phytase supplementation. Based on these equations, 500 U/kg of phytase can replace 0.52 percentage units of the dietary CP, which includes a 0.03 percentage unit improvement in Lys AID. The results of this study show that supplementing pig diets with microbial phytase improves CP and AA digestibilities in addition to Ca and P digestibilities.     

The effect of supplementary Aspergillus niger phytase in diets for pigs on concentration and apparent digestibility of dry matter, total phosphorus, and phytic acid in different sections of the alimentary tract.

Six barrows of approximately 37 kg BW, fitted with two simple T-cannulas in the duodenum (25 cm posterior to the pylorus) and terminal ileum (12 to 15 cm anterior to the ileocecal junction), were fed two diets containing 2.1 g of P/kg in the form of phytic acid and a low intrinsic phytase activity (corn-soybean meal based diet [Diet A] or a typical Dutch diet [Diet B]) without or with supplementary microbial phytase from Aspergillus niger (var. ficuum) equal to 1,500 phytase units per kilogram of diet, in a crossover design. The apparent duodenal, ileal, and total tract (overall) digestibilities of DM, total P, and phytate P (phytic acid x .282) were calculated using both Cr-NDR (neutral detergent residue mordanted with Cr) and Co-EDTA as dual-phase markers. Concentration of total P in the ileal digesta (P less than .01) and feces (P less than .001) of pigs fed microbial phytase was lower than without this enzyme, irrespective of the diet. Ileal digestibility of total P was 18.5 and 29.8 percentage units higher (which was a 1.7- to 2.9-fold increase) due to added Aspergillus niger phytase (P less than .05). Also, total tract (overall) digestibility increased by 27.0 to 29.7 percentage units (P less than .01). Phytic acid concentration in the duodenal and ileal digesta of pigs receiving microbial phytase was lower (P less than .01 or .001), resulting in its higher ileal digestibility (dephosphorylation rate) by 50.1 percentage units for Diet A and by 75.4 percentage units for Diet B. Irrespective of the treatment, no phytase activity could be detected in the ileal digesta of pigs.     

The influence of soy oligosaccharides on apparent and true ileal amino acid digestibilities and fecal consistency in growing pigs

Fourteen ileally cannulated pigs (BW = 35 +/- 2 kg) were randomly allotted to a replicated 7 x 7 Latin square design experiment to evaluate the influence of the soybean oligosaccharides (OS), raffinose and stachyose, on ileal nutrient digestibility and fecal consistency. Semipurified diets containing soy protein concentrate (SPC) or soybean meal (SBM) as the sole protein sources were fed. Soy solubles (SS), a by-product of SBM processing containing 3.5% raffinose and 11.5% stachyose, were used to increase dietary raffinose and stachyose concentrations. The seven dietary treatments were SPC, SPC + 9% SS, SBM, SBM + 9% SS, SBM + 18% SS, SBM + 24,000 U alpha-galactosidase enzyme preparation/kg diet, and a low-protein casein (LPC) diet used to calculate true digestibility. Diets, with the exception of the LPC diet, were formulated to contain 17% CP. All diets contained 0.5% chromic oxide as a marker for ileal digestibility determination. The experimental periods were divided into a 5-d diet adaptation followed by 2-d of ileal digesta collection. Diets and digesta were analyzed for DM, N, Cr, amino acids (AA), raffinose, and stachyose. Fecal consistency was determined on d 6 and 7 of each experimental period. The apparent and true ileal AA digestibilities were not different (P < 0.05) for the SPC and SBM control diets. When SS was added to the SPC diet, apparent and true N and AA digestibilities were depressed (P < 0.05) with the exception of Trp and Pro. The apparent and true ileal N and AA digestibilities were not different (P > 0.05) between the SBM control and SBM + 9% SS diets with the exception of Glu. There was a linear decrease (P < 0.05) in apparent and true DM, Val, Gly, and Tyr digestibilities when increasing levels of SS were added to the SBM diet. The addition of alpha-galactosidase did not improve apparent or true ileal N or AA digestibilities except for apparent and true Val and Tyr. Ileal raffinose digestibility was improved (P < 0.05) by addition of a-galactosidase, but was not affected by any other dietary treatment. Ileal stachyose digestibility was not affected (P > 0.58) by treatment. Fecal consistency likewise was not affected (P > 0.36) by dietary treatment. In conclusion, soy OS reduced nutrient digestibilities, but the reductions were small, ranging from approximately 1.1 to 7.4 percentage units. This suggests that other factors may be negatively impacting SBM digestibility.     

Digestibility of nitrogen and amino acids in soybean meal with added soyhulls

This study was designed to quantify the effect of soyhulls on N and AA digestibilities of soybean meal for growing pigs. Soyhulls were incorporated into 17% CP diets containing 33.25% soybean meal (SBM) at 0, 3, 6, or 9% (as-fed basis) and fed to 35-kg barrows to determine their effect on apparent and true digestibility of DM, GE, N, and AA measured at the terminal ileum. Positive and negative control diets containing 1.05% lysine were formulated with 35% SBM and 27% soy protein concentrate (SPC), respectively. A low-protein, casein-based diet was used to estimate endogenous AA losses. Soyhulls were incorporated into experimental diets at the expense of cornstarch, and SBM levels were adjusted to accommodate the contribution of CP from soyhulls. Fourteen pigs were surgically fitted with simple T-cannula at the distal ileum and fed the seven semipurified cornstarch diets based on a replicated 7 x 7 Latin square design. Each period lasted 7 d, with diet acclimation from d 1 to 5 and ileal sample collection for 12 h on d 6 and 7. Feed was offered at a level of 90 g/kg BW(0.75) in two equal portions at 0800 and 2000. Apparent ileal digestibilities of DM and GE decreased approximately six percentage units with the addition of soyhulls (linear, P < 0.05), whereas N was not affected. Both apparent and true ileal digestibilities of arginine, histidine, lysine, phenylalanine, aspartic acid, serine, and tyrosine also exhibited a decrease (linear, P < 0.05) of up to five percentage units with the addition of soyhulls. True ileal lysine digestibility of SBM decreased from 90.3 to 87.7% with the addition of 9% soyhulls. The endogenous nutrient fraction measured at the distal ileum was rich in proline, glutamic acid, and glycine, with losses greater than 1,000 mg/kg of DMI for each AA, and contained minimal amounts of tryptophan, methionine, and cystine. The current data suggest that a 0.2% decrease in some true ileal indispensable AA digestibilities may result with each 1% increase in soyhull inclusion in semipurified diets containing SBM as the sole source of AA as fed to growing pigs.     

Effects of guar gum and cellulose on digesta passage rate, ileal microbial populations, energy and protein digestibility, and performance of grower pigs

Dietary guar gum and cellulose were studied as purified soluble and insoluble nonstarch polysaccharide (NSP) sources, respectively. A control diet containing 14% cornstarch was formulated. A 7% guar gum, a 7% cellulose, and a 7% guar gum + 7% cellulose diet were formulated by adding the NSP to the control diet at the expense of cornstarch (wt/wt), forming a 2 x 2 factorial arrangement. The objectives were to determine whether guar gum and cellulose altered 1) the passage rate of digesta through the small intestine and total tract; 2) the digestibility of energy and CP, characteristics of the digesta, and microbial populations in the ileum; 3) plasma glucose and ghrelin concentrations; and 4) short-term voluntary feed intake and growth performance of grower pigs. In Exp. 1, 12 pigs (27.0 +/- 1.5 kg of BW) were fitted with an ileal T-cannula and were used in a 2-period change-over design, providing 6 observations per diet. Each period included 18 d: a 12-d acclimation period followed by 2-d feces, 3-d digesta, and 1-d venous blood collection periods. In Exp. 1, guar gum and cellulose slowed the passage rate of digesta through the small intestine by 26 and 18%, respectively (P < 0.05). Guar gum increased total tract retention time of the digesta by 14% (P < 0.05). Guar gum and cellulose increased the viscosity of ileal digesta by 72 and 76%, respectively (P < 0.05). Cellulose reduced ileal energy and CP digestibility (P < 0.05), but guar gum only tended to decrease ileal energy digestibility (P < 0.10). Guar gum and cellulose reduced total tract energy and CP digestibility (P < 0.05). At 60 min after feeding, guar gum decreased plasma glucose by 10% (P < 0.10). Guar gum interacted with cellulose to reduce plasma ghrelin before and after feeding (P < 0.05). Guar gum and cellulose interacted to increase ileal bifidobacteria and enterobacteria (P < 0.05); however, guar gum, but not cellulose, increased ileal clostridia (P < 0.05). In Exp. 2, 20 individually housed grower pigs (5 pigs per diet) had free access to the 4 diets used in Exp. 1 for 14 d. Guar gum and cellulose decreased ADG and reduced ADFI on d 0 to 14 (P < 0.05). In summary, increasing purified NSP in the diet reduced the passage rate of digesta, energy and protein digestibility, and feed intake, but increased ileal bifidobacteria and enterobacteria populations. The effects of cellulose were similar to those of guar gum. In conclusion, monitoring of dietary NSP is a critical factor to achieve predictable digestible nutrient intake and intestinal bacterial populations.     

The effect of pectin on amino acid digestibility and digesta viscosity, motility and morphology of the small intestine, and on N-balance and performance of young pigs

Two experiments were carried out using a balanced feed mixture composed of wheat, corn, soyabean meals, casein, and crystalline amino acids (AA) and supplemented with 0, 4, or 8% of apple pectin. The daily dietary allowance provided pigs with the same level of nutrients, apart from the pectin. One experiment was conducted on pigs (within 25 to 40 kg BW) with the post valve T-caecum (PVTC) cannula to determine AA digestibility and ileal digesta viscosity. In the second experiment, the N-balance was measured twice on male pigs at about 20 and 28 kg BW using 6 animals per diet and feed intake and body weight were measured twice during the 28 d. After 40 d of feeding the diets, the pigs were sacrificed and the small intestines were weighed and sampled. The added pectin decreased standardized ileal AA digestibility (on average up to 5% dig. units) and increased digesta viscosity from about 1 to 88 mPa s. The higher pectin level did not affect motility of the duodenum and mid-jejunum, measured as responses to electrical field stimulation and to acetylcholine. However, the response of the duodenum to electrical field stimulation was after feeding the diet with 4% pectin increased compared with other diets. Pectin supplementation did not alter the weight and the length of the small intestine, but induced changes in the intestinal morphology. Muscle layer width increased significantly in the duodenum, the mid-jejunum, and the ileum while villi length increased in the duodenum and ileum. The addition of pectin decreased N retention and increased the F/G ratio but did not affect significantly the ADG of the pigs.     

Dietary galactooligosaccharides affect ileal and total-tract nutrient digestibility, ileal and fecal bacterial concentrations, and ileal fermentative characteristics of growing pigs

The objective of this study was to evaluate dietary galactooligosaccharide (Gal OS) addition on swine nutrient digestibility, ileal and fecal bacterial populations, and ileal short-chain fatty acid (SCFA) production, and to determine their impact on ileal fermentative characteristics in vitro. Twelve T-cannulated pigs (BW = 25 kg) were fed a diet free of Gal OS for 21 d. On d 22, ileal digesta samples were collected for an in vitro fermentation experiment (Exp. 1). Substrates included: raffinose/stachyose combination (R + S), soy solubles (SS), and transgalactooligosaccharides (TOS). Also included were the non-OS components of SS and TOS. Nine pigs (three donors per treatment) served as ileal effluent donors. Each substrate was fermented in vitro for 6 h, and pH and SCFA and gas production were determined. Pigs then were allotted to three treatments: a Gal OS-free control diet and the control diet with either 3.5% added Gal OS from SS or TOS. Diets, feces, and digesta samples collected weekly for 6 wk on d 6 (feces) and 7 (digesta) were analyzed for DM, OM, CP, and chromic oxide concentrations. Feces and ileal digesta were analyzed for bifidobacteria and lactobacilli populations. Ileal digesta samples were analyzed for SCFA. On d 64, a second in vitro fermentation experiment (Exp. 2) was conducted using ileal effluent from three pigs per treatment and the same substrates used in Exp. 1. In vivo results showed that ileal and total tract DM and OM digestion were decreased (P < 0.05) by addition of both SS and TOS to the diet. Ileal and total-tract N digestibilities were decreased (P < 0.05) by dietary addition of SS. Fecal bifidobacteria and lactobacilli were increased (P < 0.05) by addition of SS and TOS to the diet. Ileal propionate and butyrate concentrations were greater (P < 0.05) for pigs fed diets containing both sources of Gal OS. In vitro results showed that fermentation data were not affected by donor animal adaptation to treatment. For both in vitro experiments, gas and SCFA production were higher (P < 0.05) for R + S than for SS or TOS. Fermentation of R + S resulted in a higher pH (P < 0.05) than did SS or TOS. Fermentation of non-OS components of SS and TOS resulted in more (P < 0.05) gas and SCFA production, and pH values that did not differ (P > 0.05) compared to SS and TOS. The Gal OS used in this study were prebiotics, increasing beneficial bacteria in vivo and SCFA concentrations both in vivo and in vitro.     

Effect of dietary protein content on ileal amino acid digestibility, growth performance, and formation of microbial metabolites in ileal and cecal digesta of early-weaned pigs

Diarrhea incidence in weaned pigs may be associated with the concentration of intestinal microbial metabolites (ammonia, amines, and VFA) that are influenced by dietary CP content. Three experiments were conducted to determine effects of a low-protein, AA-supplemented diet on ileal AA digestibility, growth performance, diarrhea incidence, and concentration of microbial metabolites in ileal and cecal digesta of pigs weaned at 14 d of age. In Exp. 1, 8 pigs fitted with a simple T-cannula at the distal ileum were assigned in a crossover design to 2 diets containing 24 or 20% CP using wheat, corn, full-fat soybeans, whey powder, fish meal, and blood plasma as the main ingredients. Supplemental AA were added to the diets to meet the AA standards according to the 1998 NRC recommendations. Chromic oxide was used as an indigestible marker. Diets were fed at 2.5 times the ME requirement for maintenance. The reduction of dietary CP decreased (P < 0.05) the apparent ileal digestibility of most AA, except Lys, Met, Thr, Val, and Pro. Dietary CP content did not affect the pH of ileal digesta or ileal concentrations of ammonia N, cadaverine, putrescine, or VFA. In Exp. 2, 8 pigs fitted with a simple T-cannula in the cecum were assigned to 2 diets, similar to Exp. 1. Dietary CP content did not affect the pH of cecal digesta. The reduction in CP content decreased (P < 0.05) cecal ammonia N, acetic acid, isobutyric acid, isovaleric acid, total VFA, and putrescine concentrations by 28 to 39%. In Exp. 3, 32 pigs were assigned to 2 diets, similar to Exp. 1, according to a randomized complete block design. Pigs had free access to feed and water. Dietary CP content did not affect growth performance or fecal consistency scores during the 3-wk study, and diarrhea was not observed. The results of these experiments indicate that lowering the dietary CP content combined with supplementation of AA markedly reduced the production of potentially harmful microbial metabolites in cecal digesta of early-weaned pigs without affecting growth performance.     

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

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

Determination of true ileal amino acid digestibility and the endogenous amino acid outputs associated with barley samples for growing-finishing pigs by the regression analysis technique

This study was conducted to determine true ileal AA digestibility coefficients and the endogenous AA outputs associated with barley samples for growing-finishing pigs using the regression analysis technique with dual digestibility markers. Six barrows, with 30.5 and 58.6 kg average initial and final BW, were fitted with a simple T-cannula at the distal ileum and fed six barley-based diets at close to ad libitum feed intake according to a 6 x 6 Latin square design. The six diets contained 97% of six barley samples varying from low to high in CP and AA contents (8.5, 9.2, 9.8, 11.5, 12.6, and 15.6% CP, respectively, on DM basis). The dietary NDF content ranged from 16.8 to 23.8% on DM basis. Chromic oxide (Cr2O3) and acid-insoluble ash (AIA) were used as digestibility markers. Each experimental period lasted 7 d. Ileal digesta were collected, at 2-h intervals, for a total of 24 h during d 6 and 7. There were linear relationships (P < 0.01) between dietary contents of apparent ileally digestible and total CP and AA as determined by using either Cr2O3 or AIA as a digestibility marker. The use of Cr2O3 vs AIA affected (P < 0.01) the determination of true ileal AA digestibility coefficients and the endogenous CP and AA outputs. However, there were no differences (P > 0.01) in the true ileal AA digestibility coefficients in barley samples between this study and the average values reported in the literature. The endogenous CP and AA outputs determined in this study were higher (P < 0.01) than reported values (35.1+/-3.0 vs 14.7+/-1.1 g CP/kg DMI). It is concluded that dual digestibility markers should be used to measure true ileal AA digestibility coefficients and endogenous AA outputs when dietary fiber content is high and the ileal digesta is collected through a simple T-cannula in the pig. True rather than apparent ileal AA digestibility coefficients determined in barley samples should be used in diet formulation for swine. The gastrointestinal endogenous AA secretion, recycling, and output losses are important in whole-body AA utilization and homeostasis, especially when fiber-enriched diets are fed to growing-finishing pigs.     

Effect of common antinutritive factors and fibrous feedstuffs in pig diets on amino acid digestibilities with special emphasis on threonine

Most feedstuffs contain antinutritive factors (ANF) such as insoluble fibers, lignins, tannins, and lectins. Intake of these ANF has the ability to reduce nutrient digestibility and to increase endogenous protein losses, such as through increased intestinal mucus secretion. The objective of this experiment was to determine the apparent ileal digestibilities (AID) of AA of 6 ANF-enriched diets to estimate endogenous protein loss associated with these ingredients in diets for young pigs. Forty-two 10-kg BW pigs fitted with a simple T-cannula at the distal ileum were randomly assigned to 1 of 7 casein-based diets with: no supplement (control), 100 g/kg of canola meal (CM), 100 g/kg of wheat bran (WB), 150 g/kg of barley (BR), 22.5 g/kg of lignin (LG), 15 g/kg of kidney beans [as a lectin (LE) source], and 15 g/kg of tannins (TN). All diets were formulated to be similar in N, indispensable AA, and caloric contents. After a 7-d adaptation to the test diets, N balance was conducted for 5 d, followed by 24 h of collection of digesta for analyses of AA. Pigs fed BR had 17% lower ADG and 15% lower feed conversion ratio (P < 0.05) compared with control and CM pigs. Pigs fed diets containing WB and BR had lower N retention as a percentage of absorbed N compared with all other groups (P = 0.03). The AID for CP was lower in BR, WB, and LE pigs compared with control. Of the AA, AID of Thr was notably lowest in BR, WB, and TN pigs (P < 0.05). The standardized ileal digestibility was lower in WB and BR pigs for most indispensable AA. Altogether, these data suggest that hemicellulose fiber, at concentrations typical in commercial swine diets, reduces AID of AA by increasing endogenous losses. Understanding the differential effects of ANF on endogenous losses of individual dietary AA will improve the accuracy of diet formulation.     

Effect of supplementation of xylanase and phospholipase to a wheat-based diet for weanling pigs on nutrient digestibility and concentrations of microbial metabolites in ileal digesta and feces

The objective of this study was to determine the effect of supplementing a wheat-based diet with xylanase and phospholipase either alone or in combination on the ileal and fecal digestibilities of nutrients and energy in early-weaned pigs. In addition, the concentrations of ammonia, lactate, and VFA were measured in ileal digesta and feces. The experiment was carried out with 16 barrows weaned at the age of 11 d with an average initial BW of 4.1 kg. On d 4 and 5 postweaning, the piglets were fitted with a simple T-cannula at the distal ileum. The experiment was designed as a balanced incomplete block design with three periods. The piglets received the basal diet with or without supplementation of either xylanase or phospholipase or a combination of these. There was a positive (P = 0.005 to 0.018) effect on the digestibility values of GE, OM, CP, crude fiber (CF), and NDF with xylanase supplementation. Apart from lysine, threonine, cysteine, glycine, and proline, the digestibility values of all AA were improved (P = 0.001 to 0.024). Phospholipase supplementation had a positive effect on CP (P = 0.047) and CF (P = 0.002) digestibilities, but no effect on ether extract (EE) digestibility. Supplementation of both enzymes showed the largest response in nutrient digestibilities, except that EE digestibility was not affected. No differences were found in D-/L- lactate, and ammonia concentrations among treatments. Acetate and propionate concentrations tended to increase when xylanase was supplemented and were highest for the combination of both enzymes. Despite the positive effects on ileal nutrient and energy digestibilities, there was no effect of xylanase or the combined enzyme supplementation on the fecal digestibilities of OM, CP, EE, CF, NDF, ADF, or GE, and on fecal concentrations of VFA. Phospholipase alone slightly decreased the total-tract nutrient and energy digestibilities (P < 0.05). In conclusion, the combination of both enzymes generally led to the highest increases in ileal digestibilities, which were of small numerical magnitude (approximately 2%). However, on a relative basis, this increase of 2% represents approximately 13% of the remaining diet that was available for digestion based on the fact that approximately 15% of the diet was not digested in the control pigs. Thus, the potential benefits in the nutrition of weanling pigs from combinations of enzymes should be validated under practical conditions.     

Influence of virginiamycin on the digestive physiology in precaecal re-entrant cannulated pigs.

The present experiment was set up to study the effect of Virginiamycin, a nutritional growth promoting antibiotic, on the digestive physiology using precaecal cannulated pigs. The semipurified diet used provided 21% protein and 60% of nitrogen free extract (NFE), 2/3 as starch and 1/3 as lactose. Due the older age of the pigs, the lactose induced some degree of malabsorption as precaecal flow rate of digesta was markedly higher (3.2 kg/d) compared with published data obtained with purified diets without lactose. This was also reflected in the rather low ileal digestibility of the nutrients (%): dry matter 68.6, protein 79.6, fat 78.4 and NFE 75.0. Virginiamycin markedly lowered flow rate (2.2 kg/d) and significantly improved apparent precaecal digestibilities (%): dry matter 74.0, protein 81.4, fat 81.9 and NFE 78.7. The faecal apparent digestibility was comparable with published data. There were no treatment differences indicating that precaecal digestibilities are much more sensitive then faecal ones. In order to explain the differences obtained the mean retention time in the upper intestine was measured. Although significant differences were noted (control: 5 h, Virginiamycin: 6 h) a direct cause-effect relationship was not evident. Also the activity of selected pancreatic enzymes in ileal contents was compared. There were no consistent differences between the two treatments, except for a lower lipase activity during Virginiamycin treatment.