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The heavy reliance on imported soybean meal (SBM) as a protein source makes it necessary for the European pig industry to search for alternatives and to develop pigs that perform efficiently when fed such ingredients. Digestion and metabolism are major physiological processes contributing to variation in feed efficiency. Therefore, an experiment was conducted to assess the effects of replacing SBM with increasing levels of rapeseed meal (RSM) in diets for young pigs on apparent total tract digestibility (ATTD) of energy and nutrients, nitrogen (N) balance, energy metabolism and carbohydrate, protein and fat oxidation. Four diets were fed to 32 pigs (22.7±4.1 kg initial BW) for three weeks. The diets consisted of a control cereal grain-SBM basal diet and three test diets where SBM and wheat were partially replaced with 10%, 20%, and 30% of expeller RSM. Increasing level of RSM in the diets linearly reduced ATTD of organic matter, CP, total carbohydrates, dietary fiber and energy. Utilization of digested nitrogen (DN) for N retention and total N excretion were not affected by RSM inclusion, however, RSM inclusion induced a shift in N excretion from urine to feces. Despite a linear increase in liver to metabolic BW ratio, heat production and utilization of metabolizable energy (ME) for retention were not affected by increasing RSM inclusion. In conclusion, replacing SBM with up to 30% of expeller RSM in nutritionally balanced diets for young pigs reduced the ATTD of most nutrients and energy, but did not affect N and energy retention in the body or efficiency of utilization of DN or ME for retention.

To determine chemical composition, physical characteristics and standardized ileal digestibility (SID) of CP and amino acids (AA) in eight current hulled barley genotypes, an experiment with growing pigs has been conducted. These genotypes included Yool, Campanile, Lomerit, Travira, Anisette, Canberra, Metaxa and Fridericus. Growing barrows with an average initial BW of 30±2 kg were surgically fitted with simple T-cannulas at the distal ileum, and allotted to an 8×9 Youden square design with eight periods of 6 days each and nine pigs. Barley was the sole dietary source of CP and AA. On average, the eight genotypes contained on as-fed basis 10.7% CP, 15.2% total non-starch polysaccharides (NSP), 17.1% NDF and 4.1% β-glucan, and had a mean test weight (TW) of 72.2 kg/hl. The SID of CP in the barley genotypes varied from 69% to 74%, and was greater (P<0.01) for genotypes Travira, Anisette and Metaxa compared to Yool and Campanile. Standardized ileal digestibility of Lys, Met and Trp (P<0.05) but not of Thr differed between genotypes. Moreover, barley genotypes differed in their standardized ileal digestible content (cSID) of CP and AA. Furthermore, SID and cSID of CP and most AA linearly decreased (P<0.05) with increasing NDF and total sugar content. Standardized ileal digestibility of CP and some AA and cSID of CP and most AA decreased linearly with increasing TW (P<0.05). Additionally, SID and cSID of CP and AA of most barley genotypes were lower when compared to tabulated values. In conclusion, a comprehensive database on chemical composition and SID of CP and AA in eight current barley genotypes has been made available. However, as present SID values are lower compared to feed tables, adjustments are required to minimize the risk of overestimating the actual protein value of barley for pigs.

Background: Diet influences the porcine intestinal microbial ecosystem. Barrows were fitted with ileal T-cannulas to compare short-term effects of eight different wheat or barley genotypes and period-to-period effects on seven bacterial groups in ileal digesta and faeces by qPCR., Results: Within genotypes of wheat and barley, there was no difference (P > 0.05) in contents of analysed NSP, yet cereal types differed (P < 0.001) except for soluble arabinoxylans. Genotypes showed no effect on bacterial gene copy numbers. In ileal digesta of barley- compared to wheat-fed pigs, log10 copy numbers were lower (P < 0.05) for total eubacteria (9.6-9.8), Bacteroides-Prevotella-Porphyromonas (6.5-6.8), Clostridium cluster IV (6.7-6.9), and Roseburia spp. (6.6-7.2), while higher copy numbers were found for Lactobacillus spp. (9.4-8.8). Enterobacteriaceae (7.0-7.8) and Bifidobacterium spp. (7.0-7.7) were lower (P < 0.001) in faeces of barley compared to wheat-fed pigs. Ileal eubacteria, Clostridium cluster IV and Roseburia spp. linearly increased from period 1 to 8 for both cereals (P < 0.05)., Conclusion: Wheat and barley differently influence microbial composition particularly in the small intestine, with barley increasing the Lactobacillus spp.:Enterobacteriaceae ratio, underlining its potential to beneficially manipulate the intestinal microbial ecosystem., (© 2015 Society of Chemical Industry.)

This study compared the effects of a resistant starch (RS)-rich, arabinoxylan (AX)-rich, or low-DF Western-style control diet (all high-fat) on large intestinal gene expression, adiposity, and glycemic response parameters in pigs. Animals were slaughtered after 3 weeks of treatment. Plasma butyrate concentration was higher following the high-DF diets, whereas plasma glucose, insulin, and insulin resistance increased after 3 weeks irrespective of diet. The mRNA abundance in the large intestine of genes involved in nutrient transport, immune response, and intestinal permeability was affected by segment (cecum, proximal, mid or distal colon) and some genes also by diet. In contrast, there was no diet-induced effect on adipose mRNA abundance or adipocyte size. Overall, a high level of RS or AX did not demonstrate strong beneficial effects on large intestinal gene expression as indicators of colonic health or glycemic response parameters when included in a high-fat diet for pigs as a model of healthy humans.

Two experiments were performed to study the effect of xylanase on ileal extract viscosity, in vivo fiber solubilization and degradation, and apparent ileal digestibility (AID) of fiber constituents, OM, CP, starch, and crude fat in rye and wheat in ileal-cannulated pigs. In Exp. 1, coarse rye without (NX) or with addition of xylanase from Aspergillus niger (AN), (BS), or (TR) was fed to 8 ileal-cannulated barrows (initial BW 30.9 ± 0.3 kg) for 1 wk each according to a double 4 × 4 Latin square design. In Exp. 2, fine rye, fine wheat, and coarse wheat with or without a combination of xylanase from and were fed to 6 ileal-cannulated barrows (initial BW 33.6 ± 0.5 kg) for 1 wk according to a 6 × 6 Latin square design with a 2 × 3 factorial arrangement of enzyme and cereal matrix. Chromic oxide (0.2%) was used as an inert marker. Ileal effluent was collected for 8 h on d 5 and 7 and pooled for analysis. In Exp. 1, TR reduced intestinal viscosity of pigs fed rye from 9.3 mPa·s in the control diet (NX) to 6.0 mPa·s ( < 0.001), whereas AN and BS had no effect. None of the enzymes changed the concentration of total arabinoxylan, high-molecular-weight arabinoxylan (HMW-AX), or arabinoxylan oligosaccharides (AXOS) in the liquid phase of digesta. In Exp. 2, the enzyme combination reduced intestinal viscosity for all 3 cereal matrices ( < 0.05), but the viscosity was much higher with fine rye (7.6 mPa·s) than with fine and coarse wheat (<1.7 mPa·s). Simultaneously, the total concentration of arabinoxylan in the liquid phase of digesta increased by 82.4% in fine wheat ( < 0.002) and by 45.9% in coarse wheat ( < 0.006), and AXOS increased 16-fold with enzyme addition. Similar effects of enzyme were not seen with rye. The concentration of xylooligosaccharides in the liquid phase of digesta increased with enzyme addition, but for xylose, it was only significant for wheat, for which it increased 3.9-fold ( < 0.001). None of the xylanases affected AID of arabinoxylan of rye in Exp. 1. In Exp. 2, the enzyme combination increased AID of arabinoxylan by 91% to 107% ( < 0.001) across cereal matrices. Enzyme addition did not affect AID of nutrients in any of the experiments except for a higher starch and crude fat digestibility of fine wheat with enzyme addition ( < 0.012) in Exp. 2. Collectively, the results suggest that xylanase is more efficient in degrading arabinoxylan from wheat than from rye.

Fluctuating prices of cereals have led to an interest in alternative ingredients for feed. The aim of this study was to evaluate the effect of fermentation and the addition of nonstarch polysaccharide (NSP)-degrading enzymes on the ileal and total tract digestibility of nutrients of a diet based on locally grown crops. Four diets were fed including a nonfermented liquid standard grower diet (Control) and 3 experimental diets based on high-moisture corn, rapeseed cake, and peas fed as nonfermented liquid feed (nFLF), fermented liquid feed (FLF), or FLF supplemented with an enzyme mixture of β-glucanase + xylanase + pectinase (FLF+Enz). The FLF was prepared by mixing feed and water (1:2.5, wt/wt) and, once daily, replacing 50% of the mixture with an equal amount of fresh feed and water. The diets were fed to 8 ileal cannulated barrows in a double Latin square design. Ileal digesta and feces were collected after an adaption period of 10 d. Results showed microbiologically good-quality fermented diets. The levels of Enterobacteriaceae were 5.1 to 5.4 log cfu/g in FLF and FLF+Enz vs. 6.3 log cfu/g in nFLF in the ileum and 5.1 to 5.2 log cfu/g in FLF and FLF+Enz vs. 6.3 log cfu/g in nFLF in the feces. Apparent total tract digestibility (ATTD) of CP was increased by fermentation (73.2% in FLF vs. 69.0% in nFLF; P = 0.033), and digestibility of P showed a tendency (P = 0.073) toward an increase. Addition of the enzyme mixture resulted in a pronounced reduction of dietary NSP compared with FLF (12.8% total NSP in FLF+Enz vs. 15.9% total NSP in FLF; P< 0.001), which also led to increased apparent ileal digestibility (AID) of total and insoluble NSP (total NSP, 31.1% in FLF+Enz vs. 13.6% in FLF; P = 0.002). The Control did not, in general, show higher digestibility values than the experimental diet. However, in the cases were it did, fermentation and enzyme addition brought the digestibility to the level of the Control. In conclusion, fermentation increased the ATTD of CP and the AID of P, with the same tendency (P ≤ 0.07) for the ATTD. Addition of NSP-degrading enzymes resulted in a pronounced reduction in the concentration of NSP in the feed along with increased AID of NSP. Hence, the experimental diet seems to be a possible alternative to a traditional diet for pigs.

The net absorption of betaine and choline was determined for 4 h after the first meal of the day in three experiments with porto-arterial catheterized pigs in which betaine was added as a supplement to a low-betaine diet (n=4 pigs) and compared to the net absorption of betaine and choline from high-fiber breads differing in amount and source of dietary fiber (two experiments, n=6 pigs each). Plasma betaine peaked after 30 min when betaine was fed as a supplement, whereas it peaked after 120-180 min when high-fiber breads were fed. Plasma betaine showed no diet×time interaction after feeding with high-fiber breads, indicating that the absorption kinetic did not differ between fiber sources. The net absorption of choline was not affected by the experimental diets. In conclusion, betaine in cereal sources has to be liberated from the matrix prior to absorption, causing delayed absorption.

The objectives of this work were to determine carbohydrate composition and in vitro digestibility of DM and nonstarch polysaccharides (NSP) in corn, wheat, and sorghum and coproducts from these grains. In the initial part of this work, the carbohydrate composition of 12 feed ingredients was determined. The 12 ingredients included 3 grains (corn, sorghum, and wheat), 3 coproducts from the dry grind industry (corn distillers dried grains with solubles [DDGS] and 2 sources of sorghum DDGS), 4 coproducts from the wet milling industry (corn gluten meal, corn gluten feed, corn germ meal, and corn bran), and 2 coproducts from the flour milling industry (wheat middlings and wheat bran). Results indicated that grains contained more starch and less NSP compared with grain coproducts. The concentration of soluble NSP was low in all ingredients. Cellulose, arabinoxylans, and other hemicelluloses made up approximately 22, 49, and 29% (DM basis), respectively, of the NSP in corn and corn coproducts and approximately 25, 43, and 32% (DM basis), respectively, of the NSP in sorghum and sorghum DDGS. Cellulose, arabinoxylans, and other hemicelluloses made up approximately 16, 64, and 20% (DM basis), respectively, of the NSP in wheat and wheat coproducts. The concentration of lignin in grains was between 0.8 and 1.8% (DM basis), whereas coproducts contained between 2.2 and 11.5% lignin (DM basis). The in vitro ileal digestibility of NSP was close to zero or negative for all feed ingredients, indicating that pepsin and pancreas enzymes have no effect on in vitro degradation of NSP. A strong negative correlation ( = 0.97) between in vitro ileal digestibility of DM and the concentration of NSP in feed ingredients was observed. In vitro total tract digestibility of NSP ranged from 6.5% in corn bran to 57.3% in corn gluten meal. In conclusion, grains and grain coproducts contain mostly insoluble NSP and arabinoxylans make up the majority of the total NSP fraction. The in vitro digestibility of NSP depends on the amount and type of NSP and degree of lignification in the feed ingredient. The NSP composition of grains and grain coproducts plays an important role in determining the extent of fermentation of NSP; therefore, NSP composition influences the energy value of grains and grain coproducts.

A study with growing pigs was conducted to determine the chemical composition and standardized ileal digestibility (SID) of CP and AA of 8 wheat genotypes that have recently been added to the German Descriptive Variety List. These genotypes included Tabasco, KWS Erasmus, Tobak, Skalmeje, Mulan, Event, Tommi, and Adler. The 8 genotypes were grown under identical environmental conditions on the same site, and they were harvested and processed under the same conditions. Nine barrows with an initial BW of 32 ± 2 kg were surgically fitted with simple ileal T-cannulas and allotted to a row-column design with 9 pigs and 8 periods of 6 d each. Wheat was the sole dietary source of CP and AA. Among the 8 wheat genotypes, contents of CP ranged from 10.9 to 13.3% (as-fed basis), whereas contents of total nonstarch polysaccharides ranged from 8.0 to 9.4% (as-fed basis). The SID of CP in the 8 genotypes ranged from 83 to 87%, with greatest ( = 0.01) values for Event and lowest ( = 0.01) for all other wheat genotypes. Intermediate SID of CP values were obtained for Adler and KWS Erasmus. For Lys, greater ( < 0.05) SID was observed in Adler (73%) and KWS Erasmus (74%) in comparison to Tommi, Tobak, and Mulan (69%). Adler had greater SID of Met (88%; = 0.01) when compared to Tabasco (86%); Tobak, Skalmeje, and Mulan (85%); and Tommi (84%). Among the 8 wheat genotypes, standardized ileal digestible content (cSID) of CP followed total CP content and ranged from 9.1 to 11.3% (as-fed basis). Standardized ileal digestible content of both CP and AA were greater ( < 0.001) in Adler compared to all other genotypes. For most AA, Tabasco had the lowest ( < 0.001; except for His, Trp, Asp, and Cys) cSID values of all wheat genotypes. The cSID of CP decreased ( < 0.001) as the starch content in the 8 wheat genotypes increased, but cSID of CP increased ( < 0.001) as the CP content in the 8 genotypes increased. Because SID and cSID of CP and most AA increased ( < 0.05) with lower test weight and falling number, these variables may aid to predict SID and cSID in wheat batches, whereas other nutrients such as fiber fractions are not suitable due to low variation among the 8 genotypes. The present study provides a comprehensive database on nutritional composition and SID of CP and AA of 8 wheat genotypes grown under identical conditions. Because the SID values in these genotypes are lower when compared to literature data, digestibility values in actual feed tables for wheat may overestimate their protein values and need to be updated.

The objective was to study the cause of variation in digestibility of mixed linked β(1-3;1-4)-D-glucan (β-glucan) in the small intestine of growing pigs. The β-glucan is an important cell wall [dietary fiber (DF)] component of the endosperm of barley (Hordeum vulgare) and oats (Avena sativa). The digestibility of β-glucan in the small intestine from both cereals is among the highest of all DF components, but in 1 study with oat-based diets it was lower (P < 0.001) than in other studies. In this study, whey protein containing lactose was used as protein supplement. Lactose is slowly digestible in the small intestine. To investigate if lactose might cause the lower digestibility of β-glucan in the study with whey protein, the lactose in diets was analyzed together with lactose and organic acids (lactic acids and short-chain fatty acids) in digesta samples from the small intestine (the small intestine was by length divided in 3 equal segments: SI(1), SI(2), and SI(3)) and ileal digesta. Diets containing lactose were based on oat goats, oat flour, and oat bran (12 to 38 g lactose/kg DM) whereas the reference diets were based on rolled oats, rolled oats and oat bran, wheat (Triticum aestivum) flour with added oat bran, and wheat flour with added β-glucan (0 to 1 g lactose/kg DM). Lactose was identified in digesta up to SI(2) but disappeared in digesta from SI(3) and ileum. Digestibility of β-glucan did not differ among diets up to SI(3) (18% average) whereas digestibility in ileum was 64% in diets without lactose and 27% in diets containing lactose (P < 0.001). The β-glucan was virtually completely digested in the cecum (96% average) in all diets. The concentration of organic acids did not differ between diets either in SI(3), ileum, or cecum. In conclusion, slowly digestible lactose was the most likely cause of the reduced digestibility of β-glucan in oat diets containing lactose.

Two experiments were carried out to reveal and quantify plasma metabolites that are sensitive to hemolysis and animal stress due to the blood sampling procedure (vein puncture vs. catheter). In Exp. 1, 48 sows were fed 4 diets either once (0800 h) or twice daily (0800 h and 1500 h) in a crossover design and blood was collected after restraint via vein puncture 1, 4, 11, and 23 h after morning feeding. Plasma samples were categorized as without or with minor or major hemolysis [clear (n = 218), yellow (n = 97), or red (n = 37)] upon centrifugation. Plasma NEFA (P < 0.001) was lower in hemolyzed samples but plasma propionate, caproate, isovalerate (P < 0.001), and isobutyrate (P < 0.05) were higher in hemolyzed samples. Plasma glucose and lactate were the only metabolites that were not affected by hemolysis. Interactions with hemolysis and other fixed effects were not found (P > 0.05). In Exp. 2, a subset of samples from 24 sows fed twice daily in Exp. 1 was combined with data obtained from 30 sows sampled using jugular vein catheters. All sows in Exp. 2 were fed twice daily (0800 h and 1500 h) and blood samples collected repeatedly 1, 4, 11, and 23 h after morning feeding (other conditions were similar as in Exp. 1). Plasma isobutyrate (P < 0.001), NEFA (P < 0.01), and acetate (P < 0.05) were lowered and plasma caproate (P < 0.001), glucose (P < 0.01), lactate, and isovalerate (P < 0.05) were elevated in samples obtained via vein puncture as compared to via vein catheters. Plasma insulin, propionate, and butyrate were not sensitive to the blood sampling procedure. In conclusion, blood sampling procedure and hemolysis affect the measured metabolite concentrations and should be considered or accounted for when comparing results within and between experiments.

External markers for determination of nutrient digestibility have often been evaluated in conventional dry feeds but less often in conventional feeds such as human-type diets used in animal model studies. In the present study, 5 ileal-cannulated pigs were fed 5 types of soft bread-based diets supplemented with Cr(2)O(3) and AIA as digestibility markers for 1 wk in a Latin square design. Ileal contents were collected twice for 5 h and a fecal grab sample was obtained once per week. Ileal and total tract digestibility of OM and nonstarch polysaccharides (NSP) based on the 2 markers were compared by linear regression. Across dietary treatments and site of collection, high correlation existed between digestibility values obtained with Cr(2)O(3) and AIA, resulting in a R(2) > 0.77 (P < 0.001) and a linear relation close to unity. For ileal samples, the correlation was poor, particularly for NSP, which had R(2) = 0.09 (P = 0.14) whereas OM had an R(2) = 0.52 (P <0.001). On the other hand, fecal grab samples led to R(2) > 0.92 (P < 0.001) for both OM and NSP. However, AIA gave higher values than Cr(2)O(3), particularly in samples with lower digestibility. The discrepancy is presumably caused by analytical difficulties due to a high fecal ash contents or interference with other components in the human-type diets.

The present study investigated the effects of source and level of dietary fiber (DF) and feeding frequency (once vs. twice daily) on feeding motivation and plasma metabolites at 4 different time points post feeding. Sixty pregnant sows (Sus scrofa, 4 blocks of 15 sows) were allocated to 1 of 5 diets within blocks. Four diets were restricted (approximately 35 MJ ME/d): a barley and wheat control diet (171 g DF/kg DM; 12 g DF/MJ ME), and 3 fiber diets formulated to contain 35% DF by including pectin residue (323 g DF/kg DM; 25 g DF/MJ ME), potato pulp (404 g DF/kg DM; 29 g DF/MJ ME), or sugar beet pulp (367 g DF/kg DM; 25 g DF/MJ ME). The fifth diet was a mixture including an equal amount of the 3 fiber diets offered semi ad libitum (ad libitum access to feed during 6 periods of 1 h starting at 0300, 0600, 1100, 1500, 1800, and 2300; 354 g DF/kg DM; 25 g DF/MJ ME). The experimental period included 2 periods of 4 wk each. Restricted-fed sows were fed once daily (0800 h) during the first period and twice daily (0800 and 1500 h) during the second period, or vice versa. Semi ad libitum fed sows had access to feed 6 times a day in both periods. In each period, the feeding motivation was assessed in an operant conditioning test, and samples of peripheral blood were taken in a balanced design, at 0900, 1200, 1900, and 0700 h, corresponding to 1, 4, 11, and 23 h after feeding for restricted sows fed once daily. No differences in the feeding motivation were found between the 4 restricted diets at any of the time points post feeding, but semi ad libitum fed sows had a decreased feeding motivation (P < 0.001). Among the restricted-fed sows, feeding twice daily resulted in decreased feeding motivation at 1900 h (P < 0.001) and at 0700h (P < 0.05) compared with feeding once daily, but not at 0900 and 1200 h, indicating that feeding twice daily reduced feeding motivation during the night compared with feeding once daily. Among restricted-fed sows, plasma concentrations of short-chain fatty acids (SCFA) were greater in sows fed high-fiber diets compared with the control (P = 0.02). Nonesterified fatty acid was least in sows on the control diet and greatest in sows on the potato diet, whereas sows on the pectin and sugar beet diets were intermediate (P < 0.001). Less diurnal variation in glucose (P < 0.001) was seen in sows on high-fiber diets. In spite of the found effects on plasma metabolites, the applied level of fiber in the diet of restrictedly fed sows did not reduce their feeding motivation irrespective of fiber source.

The aim of the present study was to evaluate the effects of nutrient supply, plasma metabolites, and nutritional status of sows during the transition from gestation to lactation on performance of piglets during the colostral period and throughout lactation. Forty second-parity sows were fed 1 of 4 gestation diets containing a different quantity of dietary fiber (171 to 404 g/kg of DM) from mating until d 108 of gestation. From d 108 of gestation until weaning (d 28 of lactation), sows were fed 1 of 5 lactation diets with a different quantity of dietary fat [3 or 8% with different proportions of medium- (MCFA) and long-chain fatty acids (LCFA)]. Blood was obtained by jugular venipuncture on d 108 and 112 of gestation and on d 1 of lactation, and concentrations of plasma glucose, NEFA, lactate, acetate, propionate, butyrate, and fatty acids were analyzed. Piglet growth and mortality were noted throughout lactation. Piglet mortality during the colostral period (0 to 24 h) was affected by the lactation diets and was positively related to sow backfat (d 108) and plasma lactate (d 112) and negatively related to mean piglet birth weight (P < 0.05). Mean piglet live BW gain (LWG) was recorded in the periods 0 to 24 h, 7 to 10 d, 14 to 17 d, and 17 to 28 d relative to parturition as indirect measures of colostrum yield (0 to 24 h), milk yield in early lactation (d 7 to 10), and at peak lactation (d 14 to 17 and d 17 to 28). Effects of gestation and lactation diets on studied sow traits were tested on selected days during the transition period and the next lactation, and tested statistically on separate days. The LWG in the colostral period was positively correlated with mean piglet birth weight (P < 0.001), plasma concentrations of propionate and MCFA (P < 0.05), and plasma acetate and butyrate (P < 0.1) on d 1 of lactation. The LWG in early lactation was inversely correlated with plasma lactate on d 108 (P < 0.05), plasma glucose on d 112, and backfat thickness on d 108 (P < 0.10). The LWG at peak lactation was positively correlated with MCFA intake of the sow on d 113 to 115 and backfat thickness on d 108 during the transition, and negatively correlated with intake of LCFA and ME intake on d 108 to 112 (P < 0.05). In conclusion, feeding and body condition of sows during the transition from gestation to lactation is important for neonatal piglet survival, lactation performance of sows, and piglet growth during the next lactation.

Polymeric carbohydrates, starch and nonstarch polysaccharides (NSP), quantitatively represent the largest portion of the diets for pigs and are, therefore, the largest energy contributor. The 2 types of polysaccharides, however, have different fates and functions in the gastrointestinal tract and lead to different metabolites upon digestion. Pancreatic and mucosal enzymes in the small intestine break down the majority of starch, whereas NSP primarily are degraded by the microflora in the large intestine. Starch degradation leads to the release of glucose, which is absorbed by an active absorption process that triggers the release of insulin from the pancreas, whereas the fermentation of NSP to short-chain fatty acids (SCFA; i.e., acetate, propionate, and butyrate) occurs at a slower and more constant rate and with SCFA being absorbed by passive diffusion. Type and amounts of polymeric carbohydrates influence growth and development through different mechanisms. First, the proportion of starch to NSP plays an important role for the content of available energy (i.e., DE, ME, and NE); available energy relative to protein is crucial for performance and carcass quality. Second, the proportion of starch to NSP will influence rate and type of metabolites (i.e., glucose vs. SCFA) deriving from carbohydrate assimilation. Third and finally, the type of starch (i.e., types A, B, and C) and soluble NSP will influence the release of insulin, the hormone that facilitates nutrient uptake by tissues, organs, and cells, and thus plays a critically essential role in protein synthesis and muscle growth, as well as lipid synthesis and adipose tissue growth. In conclusion, polymeric carbohydrates influence growth and development through events in the gut and direct and indirect effects of different metabolites deriving from carbohydrate assimilation., (© 2011 American Society of Animal Science. All rights reserved.)

The effects of wheat and rye breads made from whole-wheat grain (WWG), wheat aleurone flour (WAF) or rye aleurone flour (RAF) on net portal absorption of carbohydrate-derived nutrients (glucose, SCFA and lactate) and apparent insulin secretion were studied in a model experiment with catheterised pigs. The breads were similar in dietary fibre (DF, 120-125 g/kg DM) but differed in arabinoxylans (50-62 g/kg), β-glucans (4-9 g/kg) and content of soluble DF (13-29 g/kg). Six pigs in a repeated 3 × 3 crossover design were fitted with catheters in the portal vein and the mesenteric artery and a portal flow probe. Pigs were fed three meals daily (at 09.00, 14.00 and 19.00 hours), and blood profiles were collected repeatedly from 08.30 until 19.00 hours once weekly. Net portal absorption of glucose was similar among breads and between meals. In contrast, insulin secretion was lowest (P < 0·05) in pigs fed RAF bread (3·9 nmol/h), intermediate in pigs fed WAF bread (5·4 nmol/h) and highest in pigs fed WWG bread (5·9 nmol/h), indicating that RAF bread improved insulin economy. Portal concentrations of propionate, butyrate and valerate were high, intermediate and low (P < 0·05) when pigs were fed RAF, WAF and WWG breads, respectively. Insulin secretion was higher (P < 0·001), and portal absorption of SCFA was lower (P < 0·05) after the first daily meal than after the second daily meal (8·8 v. 4·4 nmol/h). A low insulin response was associated with high portal absorption of SCFA. In conclusion, RAF bread was able to improve insulin economy compared to WWG bread.

The current investigation was undertaken to study the absorption and plasma concentration of carbohydrate-derived nutrients [glucose, short-chain fatty acids (SCFA), and lactate] and the apparent insulin production in sows fed diets containing contrasting types and contents of dietary fiber. Six sows were fed 3 experimental diets, low fiber (LF; 177 g of dietary fiber and 44 g of soluble fiber/kg of DM), high soluble fiber (HF-S; 429 g of dietary fiber and 111 g of soluble fiber/kg of DM), and high insoluble fiber (HF-I; 455 g of dietary fiber and 74 g of soluble fiber/kg of DM), in a repeated crossover design. Variations in dietary concentration and solubility of dietary fiber were obtained by substituting starch-rich wheat and barley in the LF diet with dietary fiber-rich co-products (sugar beet pulp, potato pulp, pectin residue, brewers spent grain, pea hulls, and seed residue, which have distinct physicochemical properties). The main carbohydrate component of the LF diet was starch and nonstarch polysaccharides (cellulose and noncellulosic polysaccharides) for the 2 high dietary fiber diets. Consumption of the LF diet resulted in increased and rapid glucose absorption at 0 to 4 h postfeeding. With the HF-I diet, the glucose absorption pattern was similar but at a decreased rate, whereas it was decreased and delayed with the HF-S diet (diet, P < 0.001; time, P < 0.001). These differences were also reflected in the insulin response. The quantitative absorption of SCFA at 0 to 10 h postfeeding was greater when feeding the HF-S diet compared with the LF diet (P < 0.001) and intermediate when feeding the HF-I diet (P < 0.001). The study showed that feeding the high dietary fiber diets resulted in a increased and more uniform uptake of SCFA than when feeding the LF control. Moreover, the HF-S diet reduced diurnal variation in glucose and insulin concentrations.

Three experimental diets were used to investigate the digestion of carbohydrates and utilization of energy in sows fed diets with different levels and physicochemical properties of dietary fiber (DF). The low-fiber diet (LF; DF, 16%; soluble DF, 4.8%) was based on wheat and barley. The high-fiber 1 diet (HF1; DF, 41%; soluble DF, 11%) was based on wheat and barley supplemented with the coproducts: sugar beet pulp, potato pulp, and pectin residue, and the high-fiber 2 diet (HF2; DF, 44%; soluble DF, 7.3%) was based on wheat and barley supplemented with approximately 1/3 of the coproducts used in diet HF1 and 2/3 of brewers spent grain, seed residue, and pea hull (1:1:1, respectively). The diets were studied in 2 series of experiments. In Exp. 1, the digestibility and ileal and fecal flow of nutrients were studied in 6 ileal-cannulated sows placed in metabolic cages designed as a repeated 3 x 3 Latin square design. In Exp. 2, energy metabolism was measured in respiration chambers using 6 sows in a repeated 3 x 3 Latin square design. The DF level influenced the ileal flow of most nutrients, in particular carbohydrates, which increased from 190 g/d when feeding the LF diet to 538 to 539 g/d when feeding the HF diets; this was also reflected in the digestibility of OM and carbohydrates (P < 0.05). The ranking of total excretion of fecal materials was HF2 > > HF1 > LF, which also was reflected in the digestibility of OM, protein, and carbohydrates. Feeding HF diets resulted in greater CH(4) production, which was related to the amount of carbohydrates (r = 0.79) and OM (r = 0.72) fermented in the large intestine, but with no difference in heat production (12.2 to 13.1 MJ/kg of DM). Retained energy (MJ/kg of DM) was decreased when feeding HF1 compared with LF and negative when feeding HF2. Feeding sows HF1 reduced the activity of animals (5.1 h/24 h) compared with LF (6.1 h/24 h; P = 0.045).

In this study, the effect of feeding different types and amounts of dietary fiber (DF) on luminal environment and morphology in the small and large intestine of sows was studied. Three diets, a low-fiber diet (LF) and 2 high-fiber diets (high fiber 1, HF1, and high fiber 2, HF2) were used. Diet LF (DF, 17%; soluble DF 4.6%) was based on wheat and barley, whereas the 2 high-fiber diets (HF1: DF, 43%; soluble DF, 11.0%; and HF2: DF, 45%; soluble DF, 7.6%) were based on wheat and barley supplemented with different coproducts from the vegetable food and agroindustry (HF1 and HF2: sugar beet pulp, potato pulp, and pectin residue; HF2: brewers spent grain, seed residue, and pea hull). The diets were fed for a 4-wk period to 12 sows (4 receiving each diet). Thereafter, the sows were killed 4 h postfeeding, and digesta and tissue samples were collected from various parts of the small and large intestine. The carbohydrates in the LF diet were well digested in the small intestine, resulting in less digesta in all segments of the intestinal tract. The fermentation of nonstarch polysaccharides in the large intestine was affected by the chemical composition and physicochemical properties. The digesta from pigs fed the LF diet provided low levels of fermentable carbohydrates that were depleted in proximal colon, whereas for pigs fed the 2 high-DF diets, the digesta was depleted of fermentable carbohydrates at more distal locations of the colon. The consequence was an increased retention time, greater DM percentage, decreased amount of material, and a decreased tissue weight after feeding the LF diet compared with the HF diets. The concentration of short-chain fatty acids was consistent with the fermentability of carbohydrates in the large intestine, but there was no effect of the dietary composition on the molar short-chain fatty acid proportions. It was further shown that feeding the diet providing the greatest amount of fermentable carbohydrates (diet HF1, which was high in soluble DF) resulted in significant morphological changes in the colon compared with the LF diet.

Aims: To investigate which specific bacterial species that were stimulated or inhibited in the proximal colon of pigs when a fructan-rich diet was compared with a diet that contained resistant carbohydrates. The study focussed especially on Bifidobacterial species by using a noncultureable approach., Methods and Results: Terminal restriction fragment length polymorphism (T-RFLP) was used to describe differences in the total colonic microbiota as well as in the populations of Bifidobacterium spp. in pigs fed with a fructan-rich diet and a diet containing resistant carbohydrates. The fructan-rich diet has previously been shown to prevent swine dysentery caused by Brachyspira hyodysenteriae. The T-RFLP profiling, 16S rRNA gene cloning and in situ hybridization showed that the pigs fed with the fructan-rich diet had a higher proportion of Bifidobacterium thermacidophilum subsp. porcinum and Megasphaera elsdenii., Conclusions: These findings suggested that the bacterial fructan fermentation occurring in the porcine colon might be cross-feeding of lactate produced by B. thermacidophilum and used by M. elsdenii., Significance and Impact of the Study: B. thermacidophilum and M. elsdenii may be the course of the inhibition of the pathogenic bacteria Brach. hyodysenteriae in colon of pigs when they are fed fructan-rich diets.

We compared the determination of ileal and total tract digestibility of carbohydrates in five experimental diets using a double 5 x 5 Latin square design involving a total of 10 cannulated pigs; half of the pigs were equipped with a simple T-cannula and the other half with steered ileo-caecal valve (SICV)-cannula. The diets consisted of nitrogen-free mixture and soya bean meal, sunflower meal, peas or rape seed cake diluted to about 180 g/kg DM protein with the nitrogen-free mixture. There was no significant difference in the digestibility values using the two types of cannulas with regard to organic matter, sugars (sum of glucose, fructose and sucrose), alpha-galactosides (sum of raffinose, stachyose and verbascose), starch, cellulose, total non-cellulosic polysaccharides (NCP) and insoluble NCP constituents. The digestibility values for the NCP residues arabinose and galactose, however, were estimated higher but with a lower variability with the SICV-cannula compared with the T-cannula. The type of cannula did no influence the estimation of the total tract digestibility for any of the major dietary constituents, but the total tract digestibility was slightly more variable when the pigs were equipped with the SICV-cannula compared with the T-cannula. There was no difference in the ileal digestibility of sugars, alpha-galactosides, cellulose and the NCP arabinose and uronic acids residues among the experimental diets, while the ileal digestibility of starch and the remaining NCP sugar residues varied between diets. The total tract digestibility was complete for sugars, alpha-galactosides and starch, whereas the digestibility of the cell wall constituents varied in accordance with the polymeric composition of the cell walls. It was concluded that ileal digesta samples from SICV-cannula are more homogenous than those from the T-cannula. In cases where the precision of each determination is crucial, the SICV-cannula should be the option.

The present investigation was undertaken to study whether conventional male Wistar rats could be used as a model for pigs with regard to total tract digestibilities of NSP and macronutrients and whether nebacitin-treated rats could be used as a model for small intestinal digestibility in pigs. Nineteen experimental diets prepared from different fractions of wheat and oats, and which all had been evaluated in experiments with ileal cannulated pigs, were used for the present study. There was a close relationship between the total tract digestibilities of organic matter in the two species. The same was the case with regard to the digestibility of total NSP and arabinoxylans, but the values were on average 6 % lower in rats than in pigs. On average, there were no significant differences between rats and pigs with regard to faecal protein digestibility. However, protein in oat-based diets was significantly better digested in the rat than the pig. The digestibility of fat was consistently higher in rats than in pigs, with the biggest difference being found in oat-based diets, in which most of the fat was locked in cell structures. For the wheat-based diets, in which a large proportion of the fat was present as added fat, there was a greater similarity between the two species. In nebacitin-treated rats the digestibility of organic matter, starch, protein and fat was negatively related to the dietary level of NSP, but this model could not be used to predict the small intestinal digestibility of NSP and macronutrients in ileal-cannulated pigs.

The main purpose of this study was to quantify the absorption of nutrients derived from carbohydrate assimilation in a model experiment with catheterised pigs. A low-fibre (LF) diet based on wheat flour and two high-fibre diets with added insoluble fibre from wheat bran (HFWB) or soluble fibre from oat bran (HFOB) were used. The diets were offered as baked rolls to three catheterised pigs in a 3 x 3 Latin square design. The pigs were surgically fitted with catheters placed in the portal vein and mesenteric artery and with an ultrasonic flow probe attached to the portal vein to monitor the blood-flow rate. The pigs were fed the diets three times daily and portal and arterial blood samples collected twice weekly up to 8 h after the morning feeding. Glucose, insulin, lactic acid (LA) and short-chain fatty acids (SCFA) were determined on the samples. The baseline level of glucose in the portal vein was about 6 mmol/l increasing to 10-11 mmol/l 20-30 min post-feeding with no difference among the different diets. Portal and arterial insulin mirrored portal glucose concentration and was also unaffected by the dietary composition. The net absorption of glucose (per 24 h) was: diet LF 4190 mmol; diet HFWB 3050 mmol and diet HFOB 3190 mmol corresponding to a recovery of 0.76-0.92 of ingested starch. The levels of LA and SCFA in the portal vein were relatively constant in the postprandial period. The net absorption of LA and SCFA was in the same order (749 and 720 mmol/d respectively) with diet LF, while LA was lower (384 and 582 mmol/d) and SCFA higher (738 to 891 mmol/d) when feeding the two high-fibre diets. There was a higher molar proportion of butyrate in the portal vein after feeding the high-fibre diet supplemented with oat bran as compared with the wheat-based diets.

To study the intestinal metabolism of lignans, the concentrations of plant and mammalian lignans in intestinal digesta sampled along the intestinal tract of pigs were determined by isotope dilution GC-MS. The pigs were fed rye-bread diets made from either whole rye-grains or rye-grain milling fractions enriched in pericarp-testa, aleurone or endosperm cells. The content and characteristics of dietary fibre varied between diets and had been shown to induce different colon fermentation patterns. As the metabolism of lignans depends on the action of the intestinal flora, we tested whether the rye-bread diets influence the metabolism of lignans. In the ileum, the lignans were mainly present as conjugated plant lignans, which were determined only when the analytical procedure included a hydrolysis step. High recovery of dietary lignans in the ileum may indicate that the lignans enter the enterohepatic circulation. In addition, two to three times the intake of lignans were recovered in the faeces when the diets had a high content of dietary fibre suggesting underestimation of plant lignans in the diet. Most of the plant lignans disappeared from the intestinal tract between the terminal ileum and the caecum. The intestinal concentrations and the disappearance of lignans correlated with the content of lignans in the diet, being highest on the pericarp-testa diet and lowest on the endosperm diet. No effect of fermentation pattern on the intestinal metabolism of lignans was observed. The lignans were liberated from the pericarp-testa diet although the plant cell walls remained largely undegraded.

In order to investigate the effects of dietary fibre (DF) characteristics on carbohydrate degradation and the metabolism in the large intestine, pigs were fed on four rye-bread diets (based on whole rye, pericarp/testa, aleurone or endosperm) with differences in characteristics and amount of DF. The degradability of DF in the large intestine varied greatly between diets. The pericarp/testa DF was hardly degraded in the large intestine, whereas endosperm DF was extensively and rapidly degraded in the caecum. Caecal degradation of aleurone DF was also limited, leaving more material to be degraded in the colon. The undegradable pericarp/testa DF was characterized by high contents of lignin, cellulose, ferulic acids and highly substituted arabinoxylans (the major DF component in rye). Ingestion of this diet resulted in increased faecal bulk and reduced transit time, but with low colonic pH and the lowest concentrations of shortchain fatty acids (SCFA). The aleurone diet, on the other hand, led to a fermentation pattern which may be considered more optimal, with lower colonic pH and higher concentrations of SCFA, in particular butyric acid. Despite the large differences in carbohydrate fermentation only minor significant effects on the presence of protein degradation products and on histological measurements (height and diameter of colonic crypts and thickness of the muscularis external) were observed.

The effect of cereal-based diets varying in dietary fibre (DF) on gastric emptying and glucose absorption over an isolated loop of jejunum was studied in four pigs fitted with two sets of re-entrant cannulas. The pigs were fed on either a wheat-flour diet or three diets based on oat flour (endosperm), rolled oats or oat bran containing different amounts of soluble DF. Mean transit time (MTT) of liquid estimated from the output from the first jejunal cannula was significantly higher with the two diets having the highest DF content, but MTT of dry matter (DM), starch, xylose and neutral non-starch polysaccharides (nNSP) was not correlated directly to the DF content of the diet. DF had a stimulatory effect on secretion of gastrointestinal juices, but the effect was not linearly correlated with the DF content of the diet. Starch was significantly degraded in digesta collected within 30 min after feeding with malto-oligosaccharides accounting for 140-147 g/kg total starch. The degradation was more extensive with higher DF and lower starch content of the diet. However, taking into account the differences in jejunal flow, the amount of malto-oligosaccharides available for absorption in the first 0.5 h decreased with higher levels of DF in the oat-based diets. The absorption of glucose from the isolated loop was 18-34 g/m intestine over an 8 h period with no significant differences between diets. This corresponded to a non-significant decrease in recovery of starch from 0.91 to 0.82 with increasing levels of DF and decreasing levels of starch in the diet. This suggests that the capacity for absorption of large doses of starch entering the proximal small intestine after ingestion of a carbohydrate-rich cereal-based diet has a major influence on the absorption at this site. Consequently any effect of DF on glucose absorption may be exerted either through the rate of gastric emptying or by impaired rate of absorption more distal in the small intestine and not by displacement of the site for starch absorption.

The present work was undertaken to study the microbial activity in various segments of the gastrointestinal (GI) tract of pigs as influenced by the source and level of wheat and oat dietary fibre (DF). Eight experimental diets were prepared from wheat and oat fractions and studied in a series of two experiments using wheat flour as the DF-depleted control. The diets in Expt 1 were based on wheat flour and three iso-DF enriched diets comprising fractions rich in wheat aleurone, pericarp/testa or bran. In Expt 2, oat bran was added to wheat flour to achieve the same DF intake level as in Expt 1. This series included further diets based on rolled oats and rolled oats plus oat bran. The eight diets were given to thirty-two ileal-cannulated pigs, with sixteen pigs in each experiment. After a total period of 34 d (Expt 1) and 42 d (Expt 2), the pigs were slaughtered 4 h post-feeding and samples taken for adenine nucleotides (adenosine 5'-triphosphate (ATP); adenylate energy charge (AEC)), organic acids (lactic acid (LA); short chain fatty acids (SCFA)) and pH at twelve sites of the GI tract. The microbial activity as measured by the ATP concentration was low in the stomach and the cranial two-thirds of the small intestine, but tended to increase in the distal third. In the caecum a sharp rise in microbial activity was observed; the highest level was found for the diet providing most fermentable substrates. In all the diets but the rolled oats + oat bran diets, microbial activity showed a descending pattern as the digesta moved through the colon. In the large intestine source and level of residues had a marked influence on microbial activity. LA was the chief organic acid in the stomach and small intestine (10-40 mmol/l) while LA relative to SCFA was a minor component in the caecum and colon (10-20 mmol/l). The contribution of SCFA to total organic acids was reciprocal to LA, i.e. low in the stomach and small intestine (less than 20 mmol/l) and high in the caecum and colon. In the large intestine the concentration of SCFA decreased from 100-140 mmol/l in the caecum and proximal colon to 40-80 mmol/l in the distal colon. The acetic: propionic acid ratio increased from the caecum to the distal colon. With the diets based on oat alone (rolled oats; rolled oats + oat bran) the increase was less significant.(ABSTRACT TRUNCATED AT 400 WORDS)

The present work was undertaken to study the gastrointestinal effects of wheat and oat dietary fibre (DF) using 40-50 kg pigs cannulated in the terminal ileum. The variables studied were: chemical characteristics of the DF, ileal and faecal digestibility of nutrients and bulking properties of polysaccharides and other major constituents. The wheat products studied included refined wheat flour and wheat fractions rich in the following botanical components: aleurone, pericarp/testa and bran. The oat products used were rolled oats and oat bran. The products varied considerably in DF content (g/kg dry matter) and composition; non-starch polysaccharides (NSP) and Klason lignin content ranged from 34 and 1 g/kg respectively in wheat flour, to 465 and 92 g/kg in pericarp/testa. The main NSPs in the wheat were arabinoxylans (AX) (64-69%) and cellulose (15-31%) and in oats mixed linked beta(1----3; 1----4-D-glucans (beta-glucans; 46-63%) and AX (28-32%). The lowest content of soluble NSP was found in the lignified wheat fractions (bran and pericarp/testa) and the highest in oat bran. Eight diets were produced using the wheat and oat products and studied in two series of experiments using wheat flour as the DF-depleted control. The diets in Expt 1 were based on wheat flour and three iso-DF enriched diets prepared by adding DF from the fractions rich in wheat aleurone, pericarp/testa or bran. In Expt 2, oat bran was added to wheat flour to achieve the same DF intake level as in Expt 1. This series also included diets based on rolled oats and rolled oats plus oat bran. Starch was almost completely digested in the small intestine (0.97-1.00). However, there was a tendency to a slightly lower digestibility of oat starch compared with wheat starch. The recovery of wheat NSP in ileal digesta was 82-104% compared with 64-66% for oats. The low recovery of NSP in oat diets was primarily due to the low recovery of beta-glucans (25-36%). In the large intestine NSP and starch residues were extensively degraded. For the DF-depleted control diets or diets based on oats, 8-17% NSP survived breakdown while in the diets enriched with aleurone, pericarp/testa or bran fractions, NSP recovery was 33, 50 and 38% respectively. Fermentative breakdown of carbohydrates in the large intestine was estimated to contribute between 10 and 24% of the energy for maintenance. Energy derived from the inflow of organic acids from the ileum contributed an additional 1-4% of maintenance energy.(ABSTRACT TRUNCATED AT 400 WORDS)