The present study aimed to validate an in vitro enzymatic technique that estimates the coefficient of apparent ileal digestibility (CAID) of the starch and amino acids of eight varieties of field peas (Pisum sativum) in adult pigs. Eight adult pigs (132±6.9kg) with a ileal T-cannula were fed for seven days with a synthetic diet containing one of the field peas as the only protein source in an incomplete Latin Square design (n=6 pigs/treatment). Ileal digesta were collected for the last three days of each period. The in vitro degree of starch hydrolysis of all pea samples was determined after a sequential hydrolysis carried out by pepsin (120min) and a mixture of pancreatin, isomaltase and maltase (240min). A high linear relationship was observed between the in vitro and in vivo starch digestion (Y=1.12X−0.052; adjusted r2=0.76, P<0.01, residual standard deviation=0.51). The CAID of starch was negatively correlated with starch content (r=−0.71, P<0.05), but positively correlated with CAID of dry matter (r=0.48, P<0.001). In conclusion, the in vitro technique used in this study as well as the pea composition can be used to predict in vivo ileal starch digestibility of peas in adult pigs.

Based on previously performed in vitro studies, which showed that hulless barley varieties could reduce large intestinal Salmonella Typhimurium var. Copenhagen proliferation in pigs, two in vivo experiments were conducted to prove these observations. In Experiment (Exp.) 1, 126 weaning piglets were randomly allocated into pens of seven animals each and fed one of six experimental diets. Three diets contained (75% as-fed) one of three hulless barley varieties with beta-glucan (BG) contents ranging from 5 to 11% and amylose from 5 to 40%, and two diets contained a low BG and amylose hulless barley supplemented with isolated barley BG or raw potato starch. A hulled barley diet served as a control. Two piglets per pen ("Trojan" pigs) were orally infected with Salmonella Typhimurium var. Copenhagen (ST). The remaining five pigs per pen were designated "Contact" pigs. The ST shedding was determined over one week after infection. On day 6, the two Trojans and two random Contacts from each pen were euthanised and intestinal contents and mesenteric lymph nodes cultured for ST. Intestinal volatile fatty acids and microbial composition were determined. In Exp. 2, 126 piglets were assigned to one of three diets based on hulled or hulless barleys. The timeline, infection, sampling and analyses were similar as in Exp. 1 except samples were taken from four Contact pigs. Hulless barley varieties with high BG and amylose tended to decrease ST persistence in Exp. 1. Clostridia from cluster I in the colon were reduced with high amylose hulless barley or diets supplemented with potato starch (p < 0.05), whereas other microbial groups were not. Propionate increased (p < 0.05) and acetate decreased (p < 0.05) with hulless barley inclusion. Exp. 2 revealed a reduced ST shedding and reduced number of clostridia for high BG hulless barley as compared to common hulled barley and a low BG variety (p < 0.05). In conclusion, high BG hulless barley do not prevent ST colonisation but might help to reduce transmission in pigs, likely by supporting an intestinal environment limiting growth of this zoopathogen.

A study was conducted to determine the effect of particle size of field peas on (1) the digestible energy (DE) content in growing pigs of 11 field pea varieties and (2) the kinetics of starch hydrolysis of five of these field pea varieties measured in vitro. Each field pea variety was ground with three screen opening-sizes: 5.4, 3.28 and 0.74 mm, resulting in a geometric mean particle size (GMPS) of 1035, 649 and 156 μm, respectively. A total of 204 growing pigs (28 ± 2 kg; 34 treatments with 6 pigs/treatment) were fed for 13 d with a basal diet composed of cereals, soybean meal and a premix or 33 pea-based diets (0.3 field pea and 0.7 basal diet) supplemented with Celite (indigestible marker). Faeces were collected by grab sampling for the last 3 d. A sequential in vitro hydrolysis of the starch of five of these field pea varieties at the three GMPS was conducted with pepsin (120 min) and a mixture of pancreatin, isomaltase and maltase enzymes (240 min). The DE concentration of the field peas varied from 13.38 to 16.05 MJ/kg DM (P<0.01). The average DE (16.1, 14.7 and 14.0 MJ/kg DM) decreased linearly with increasing GMPS (P<0.001). The differences in the degree of starch hydrolysis were influenced by the interaction "field pea variety × GMPS" (e.g. for 1035 and 649 μm of GMPS, the hydrolysis for the Acer variety was 0.90 and 0.49 vs. 0.47 and 0.40 for the Pekoe variety, respectively; P<0.001). There was a positive correlation between the DE and the degree of starch hydrolysis (r = 0.62; P=0.02). In conclusion, the DE of ground field pea varieties in growing pigs increases linearly as GMPS decreases. The differences in DE observed between field pea varieties can be explained by differences in starch hydrolysis and GMPS.

An in vitro experiment was carried out using the gas technique to study the fermentation characteristics of different feed ingredients differing in their fermentable carbohydrate and protein composition by colonic bacteria isolated from pigs. The effect on in vitro bacterial protein synthesis was also evaluated. The ingredients used were wheat bran (WB), wood cellulose (Solka-floc®, SF), peas, pea hulls (PH), pea inner fibre (PIF), sugar beet pulp (SBP), flax seed meal (FSM) and corn distillers dried grains with solubles (DDGS). The samples were pre-treated with pepsin and pancreatin and the hydrolyzed substrates were then incubated with pig faeces in a buffered mineral solution. The nitrogen source in the buffer solution (NH4HCO3) was replaced by an equimolar quantity of 15N-labeled NH4Cl, used for the determination of the rate of bacterial protein synthesis. Gas production, proportional to the amount of fermented carbohydrate, was recorded for 48h and modelled. The fermented product was subjected to short-chain fatty acids (SCFA) analysis. The source of fibre affected the in vitro dry matter degradability (IVDMD), the fermentation kinetics and the gas production profile (P<0.05). The highest (P<0.001) IVDMD values were observed for peas (0.80) and FSM (0.70), whereas SF was essentially undegraded (0.06). The fractional rate of degradation appeared to be lower (P<0.001) for WB and DDGS (0.07 and 0.05h, respectively) and highest for SBP (0.20h). Peas started to ferment rapidly (lag time 1.3h). Half gas production (T/2) was achieved sooner for PIF (8.4h) and was the longest for DDGS (19.8h). The total gas production was the highest for PH, followed by SF, PIF and peas (276, 266, 264 and 253ml/g DM incubated, respectively) and the lowest for FSM and WB (130 and 124ml/g DM incubated, respectively). There was no difference (P>0.05) in SCFA production after the fermentation of SF, P, PH, PIF and SBP (ranging from 3.8 to 4.5mmol/g DM incubated) while WB and FSM yielded lowest (P<0.05) SCFA. The bacterial nitrogen incorporation (BNI), both at T/2 and after 48h of fermentation was the highest (P<0.001) for PIF (18.5 and 15.6mg/g DM incubated, respectively) and the lowest for DDGS and WB. In conclusion, peas and pea fibres had higher rates of fermentability, produced more SCFA and had high bacterial protein synthesis capacity. They thus have the potential to be included in pig diets as a source of fermentable fibre to modulate the gut environment and reduce nitrogen excretion.

Prairie Swine Centre inc., 2105 – 8th Street East, Saskatoon, SK, S7H 5N9, Canada Department of Poultry and Animal Science, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK, S7N 5A8, Canada University of Liege, Gembloux Agro-Bio Tech, Animal Science Unit, Passage des Déportés 2, 5030, Gembloux , Belgium Present address: Institute of Animal Nutrition, Department of Veterinary Medicine, Freie Universität Berlin, Königin-Luise-Str. 49, D-14195 Berlin, Germany Present address: Riddet Institute, Private Bag 11, 222
Palmerston North, 4442
New Zealand

An in vitro experiment was carried out to assess how nonstarch polysaccharide (NSP)-degrading enzymes influence the fermentation of dietary fiber in the pig large intestine. Seven wheat and barley products and cultivars with differing carbohydrate fractions were hydrolyzed using pepsin and pancreatin in the presence or not of NSP-degrading enzymes (xylanase and β-glucanase) and the filter retentate was subsequently fermented with sow fecal bacteria. Dry matter, starch, crude protein and β-glucan digestibilities during hydrolysis were measured. Fermentation kinetics of the hydrolyzed ingredients were modelled. Short-chain fatty acids (SCFA) production and molar ratio were compared after 12, 24 and 72 h. Microbial communities were analyzed after 72 h of fermentation using terminal restriction fragment length polymorphism. The results showed an increase of nutrient digestibility (P<0.001), whereas fermentability and SCFA production decreased (P<0.001) with addition of the enzyme. SCFA and bacterial community profiles also indicated a shift from propionate to acetate and an increase in cellulolytic Ruminococcus- and xylanolytic Clostridium-like bacteria. This is explained by the increase in slowly fermentable insoluble carbohydrate and the lower proportion of rapidly fermentable β-glucan and starch in the retentate when grains were incubated with NSP-degrading enzymes. Shifts were also different for the four barley varieties investigated, showing that the efficiency of the enzymes depends on the structure of the carbohydrate fractions in cereal products and cultivars.

An in vitro model was used to study the fermentation characteristics of carbohydrate fractions of hulless barley (hB), in comparison to hulled barley (HB), hulled oat and oat groats (OG) in the pig intestine. For this purpose, 6 hulless barley cultivars (hB), varying in β-glucan content (36–99g/kg DM), were compared to 3 HB cultivars, 2 oat groat samples (OG), 3 oat varieties and a reference sample of wheat. The residue of a pepsin–pancreatin hydrolysis was incubated in a buffered mineral solution inoculated with pig faeces. Gas production, proportional to the amount of fermented carbohydrates, was measured for 48h and kinetics modelled. The fermented solution was subsequently analyzed for microbial production of short-chain fatty acids (SCFA) and ammonia. In vitro dry matter degradability varied according to ingredient (P<0.001). Higher values were observed for OG, ranging from 0.88 to 0.99 as compared to oat, hB and HB, for which degradability ranged from 0.63 to 0.73, 0.68 to 0.80 and 0.69 to 0.71, respectively. A “cereal type” effect (P<0.05) was observed on fermentation kinetics parameters. Total gas production was higher (P<0.05) with hB (224ml/g DM incubated) than with HB and oat (188 and 55ml/g DM incubated, respectively). No difference was observed between hB cultivars (P>0.05) for total gas production but differences (P<0.001) were found for lag time and the fractional rate of degradation. Hulless barley cultivar CDC Fibar (waxy starch) and CDC McGwire (normal starch) started to ferment sooner (lag time of 0.7 and 0.9h, respectively) than SH99250 (high amylose starch; 1.7h). The fractional rate of degradation was similar in both hB and OG (0.15/h on average), which was higher than that of HB (0.12/h). The production of SCFA was also higher (P<0.05) with hB (6.1mmol/g DM incubated, on average) than with HB and oat (4.9 and 2.9mmol/g DM incubated, respectively). Similar trends were found for SCFA production expressed per g fermented carbohydrates, with higher butyrate and lower acetate ratio. In contrast, oat fermentation generated higher (P<0.05) ammonia concentration (1.4mmol/g DM incubated, on average) than hB (1.0mmol/g DM incubated). In summary, hulless barleys, irrespective of cultivar type had higher in vitro fermentability and produced more SCFA and less ammonia than hulled barley and oat. Thus, hulless barleys have a better potential to be used in pig nutrition to manipulate the fermentation activity in the intestine of pigs.

To study the fermentation characteristics of different non-conventional dietary fibre (DF) sources with varying levels of indigestible CP content and their effects on the production of fermentation metabolites and on faecal nitrogen (N) excretion, an experiment was conducted with 40 growing pigs (initial BW 23 kg) using wheat bran (WB), pea hulls (PH), pea inner fibres (PIF), sugar beet pulp (SBP) or corn distillers dried grains with solubles (DDGS). The diets also contained soya protein isolate, pea starch and sucrose, and were supplemented with vitamin-mineral premix. Faecal samples were collected for 3 consecutive days from day 10, fed with added indigestible marker (chromic oxide) for 3 days from day 13 and pigs were slaughtered on day 16 from the beginning of the experiment. Digesta from the ileum and colon were collected and analysed for short-chain fatty acids (SCFA) and ammonia (NH3) content. The apparent total tract N digestibility was the lowest (P < 0.001) in diets based on DDGS (74%), medium in diets with WB and SBP (76% each) and highest in those with PIF and PH (79% and 81%, respectively). Expressed per kg fermented non-starch polysaccharides (NSP), faecal N excretion was higher with DDGS and WB diets (130 and 113 g/kg NSP fermented, respectively) and lower with PIF, PH and SBP diets (42, 52 and 55 g/kg NSP fermented, respectively). The PH-based diets had the highest (P < 0.05) SCFA concentrations, both in the ileum and the colon (27 and 122 mMol/kg digesta, respectively). The highest NH3 concentration was also found in the colon of pigs fed with PH (132 mMol/kg digesta). Loading plot of principle component analysis revealed that the CP : NSP ratio was positively related with faecal N excretion and NH3 concentration in colon contents, whereas negatively related with SCFA concentration in colon contents. In conclusion, pea fibres and SBP increased SCFA and reduced NH3 concentration in the pig's intestine and reduced faecal N excretion, which makes pea fibres and SBP an interesting ingredient to use in pig diet to improve the positive effect of DF fermentation on the gastrointestinal tract and reduce faecal N excretion.

This article proposes a new way to improve the protein quality of the common bean (Phaseolus vulgaris). It is based on the natural variability found in the different types of phaseolin, its main storage protein (40–50% of the total protein). Despite the fact that it is deficient in methionine content, phaseolin still represents the main source of that amino acid in the seed. More than 40 genetic variants, differing in subunit number (2–6) and molecular weight (40–54 kDa) have been analyzed. The similarity of the amino acid composition among phaseolins, suggests that a nutritional improvement cannot be expected from that side. Conversely, important variation in phaseolin susceptibility to proteolysis (ranging from 57% to 96% after cooking) has been observed, increasing the theoretical availability of methionine by up to 37%. Therefore, breeding programs based on highly-digestible phaseolin types could lead to the production of beans with higher protein quality.

Dietary protein might modulate mucin flow and intestinal mucin gene expression. Since unheated phaseolin fromPhaseolus vulgarisbean is resistant to digestion and increases gut endogenous protein losses, we hypothesised that unheated phaseolin influences mucin flow and gene expression, and that phaseolin heat treatment reverses these effects. The hypothesis was tested using a control diet containing casein as the sole protein source and three other diets with casein being replaced by 33 and 67 % of unheated and 67 % of heated phaseolin. The rats were fed for 6 d and euthanised. Digesta and faeces were collected for determining digestibility and mucin flow. Gut tissues were collected for mucin (Muc1,Muc2,Muc3andMuc4) and Trefoil factor 3 (Tff3) gene expressions. Colonic mucin flow decreased linearly with increasing the dietary level of unheated phaseolin (P < 0·05). Unheated phaseolin increased N flow in ileum, colon and faeces (P < 0·05), and reduced apparent N digestibility linearly (P < 0·01). Heat treatment reversed all these changes (P < 0·05 to < 0·001), except mucin flow. The expressions ofMucmRNA in gut tissues were influenced by dietary phaseolin level (ileum and colon:Muc3andMuc4) and thermal treatment (ileum:Muc2; colon:Muc2,Muc3,Muc4andTff3) (P < 0·05 to 0·001). In conclusion, phaseolin modulates mucin flow andMucgene expression along the intestines differentially.

Dietary protein might modulate mucin flow and intestinal mucin gene expression. Since unheated phaseolin from Phaseolus vulgaris bean is resistant to digestion and increases gut endogenous protein losses, we hypothesised that unheated phaseolin influences mucin flow and gene expression, and that phaseolin heat treatment reverses these effects. The hypothesis was tested using a control diet containing casein as the sole protein source and three other diets with casein being replaced by 33 and 67 % of unheated and 67 % of heated phaseolin. The rats were fed for 6 d and euthanised. Digesta and faeces were collected for determining digestibility and mucin flow. Gut tissues were collected for mucin (Muc1, Muc2, Muc3 and Muc4) and Trefoil factor 3 (Tff3) gene expressions. Colonic mucin flow decreased linearly with increasing the dietary level of unheated phaseolin (P < 0·05). Unheated phaseolin increased N flow in ileum, colon and faeces (P < 0·05), and reduced apparent N digestibility linearly (P < 0·01). Heat treatment reversed all these changes (P < 0·05 to < 0·001), except mucin flow. The expressions of Muc mRNA in gut tissues were influenced by dietary phaseolin level (ileum and colon: Muc3 and Muc4) and thermal treatment (ileum: Muc2; colon: Muc2, Muc3, Muc4 and Tff3) (P < 0·05 to 0·001). In conclusion, phaseolin modulates mucin flow and Muc gene expression along the intestines differentially.

Aquatic ferns (AFs) such as Azolla filiculoides and Salvinia molesta are grown on swine lagoons in the tropics and used in diets for pigs. The present work is aimed at evaluating their potential as feed ingredients for sows. When presented with ad libitum AFs, gilts weighing 110±14kg (mean±SD), were able to ingest 9.1–9.7kg fresh AF per day (from 597 to 630gdry matter (DM) per day) and from 1240 to 1428gDM per day when presented in a dry, ground form. A digestibility study was conducted, using sows weighing 213±9kg (mean±SD), which were fed diets containing maize, soybean meal and 0, 150 or 300gAFkg−1 diet. The presence of AFs had a negative impact on the faecal digestibility of the crude protein, NDF and energy content of the whole diet (P<0.001) and on the ileal protein digestibility, especially with 300gAFskg−1 diet. The level of AFs in the diet had no effect on stomach weight (P>0.05) but increased the weight of the rest of the gastrointestinal tract (P<0.001). The rate of AF fibre fermentation in the pig large intestine was measured using an in vitro gas test. The rates were much lower than tropical tree foliage, which can also be used in pig diets in the tropics. This could partly explain the low apparent digestibility of AFs in pigs. In conclusion, the inclusion level of AFs in rations for sows should be limited to 150gAFskg−1 diet due to the low digestibility and energy density, as well as the negative impact on the digestibility of the whole diet.

The influence of variation in carbohydrate (CHO) composition within the same type of cereal on intestinal fermentation patterns and microbial community composition in the pig is unknown. Ten hulless barleys (HLB), 6 hulled barleys (HB), 6 oats (O) and 6 oat groats (OG) differing in CHO composition were studied in vitro. They were hydrolyzed enzymatically, inoculated with pig feces and fermented for 72h. Multivariate analysis revealed that microbial profiles analyzed using TRFLP, short-chain fatty acid (SCFA) and fermentation parameters were affected by CHO composition but differently according to the grain type (HLB, HB, O or OG). Members of Clostridium cluster XIVa were associated to higher amylose contents and butyrate production in HB cultivars and in HLB cultivars. Several clostridia phylotypes increased with β-glucan content in HLB and HB. Cellulolytic Ruminococcus-like bacteria tended to increase acetate concentration and were increased with cellulose content in HB, HLB and OG. Bacteroides-like bacteria were increased by amylopectin and starch content of barley cultivars. Cereal cultivars differing in CHO composition can alter the pig intestinal microbial ecophysiology to possibly improve gut health.

Each paper should commence with an accurate and informative abstract, written as a single paragraph. It should be complete in itself and intelligible without reference to the text or figures, and should not exceed 250 words. Tables. Tables should be reduced to the simplest form, and should not duplicate information in the text or figures. They should be typed on separate pages, one page for each Table, at the end of the article and carry headings describing their content. Illustrations. The original illustrations should accompany the submitted typescript. Text figures, line drawings, computer-generated figures and graphs should be of sufficient size and quality to allow for reduction by half or two-thirds. Half-tone photographs are acceptable where they clearly contribute to the text. All figures should be numbered and legends should be provided. Note that authors will be charged 350 GBP for the publication of colour figures. Authors from countries entitled to free journal access through HINARI will be exempt from these charges. References. References should be based on the numbered (Vancouver) system. When an article has more than ten authors, only the names of the first three should be given followed by et al.; give abbreviated journal titles and conform to the following styles: Goel V, Cheema SK, Agellon LB, Ooraikul B & Basu TK (1999) Dietary rhubabrb (Rheum rhaponticum) stalk fibre stimulates cholesterol 7α-hydroxylase gene expression and bile acid excretion in cholesterol-fed C57BL/6J mice. Br J Nutr 81, 65–71. Jenkins DJ, Kendall CW, Marchie A, et al. (2003) The effect of combining plant sterols, soy protein, viscous fibres, and almonds in treating hypercholesterolemia. Metabolism 52, 1478–1483. Brandtzaeg P (2003) Role of local immunity and breast-feeding in mucosal homoeostasis and defence against infections. In Nutrition and Immune Function, pp. 273–320 [PC Calder, CJ Field and HS Gill, editors]. Wallingford, Oxon: CAB International. Stock M & Rothwell NJ (1982) Obesity and Leanness: Basic Aspects. London: John Libbey. Citations should be numbered consecutively in the order in which they first appear in the text using superscript Arabic numerals in parentheses, e.g. ‘The conceptual difficulty of this approach has recently been highlighted(1,2–4). If a reference is cited more than once the same number should be used each time. Referees. Authors are asked to submit the names of up to four scientists who would be well-qualified to review the paper; however, no more than one such reviewer will be used. The email addresses and institutions of the named reviewers should be given. Proofs. PDF page proofs will be emailed to authors for checking, and should be returned within 3 days (by fax or Express mail) to the BJN Production Editor, Cambridge University Press, The Edinburgh Building, Shaftesbury Road, Cambridge CB2 2RU, UK; fax +44 1223 325802, email bjnproduction@cambridge.org Typescripts. The British Journal of Nutrition operates an on-line submission and reviewing system (eJournalPress). Authors should submit to the following address: http://bjn.msubmit.net/ If any difficulties are encountered please contact the Publications Office (details above) immediately. Professor Philip Calder Editor-in-Chief British Journal of Nutrition The Nutrition Society 10 Cambridge Court 210 Shepherds Bush Road London W6 7NJ UK Tel: +44 (0)20 7605 6555 Fax: +44 20 7602 1756 Email: edoffice@nutsoc.org.uk British Journal of Nutrition Directions to Contributors Concise Version (Revised August 2007) British Journal of Nutrition, published by Cambridge University Press on behalf of the Nutrition Society 2010© British Journal of Nutrition An International Journal of Nutritional Science Volume 104, 2010 ISSN: 0007-1145 Aims and Scope The British Journal of Nutrition is an international, peer-reviewed journal publishing original papers, review articles, short communications and technical notes on human and clinical nutrition, animal nutrition and basic science as applied to nutrition. Correspondence is encouraged in a Nutrition Discussion Forum. The Journal recognizes the multidisciplinary nature of nutritional science and encourages the submission of material from all of the specialities involved in research and clinical practice. The Journal also publishes supplements on topics of particular interest. The British Journal of Nutrition is published twice monthly by Cambridge University Press on behalf of The Nutrition Society. The British Journal of Nutrition is available online to subscribers at journals.cambridge.org/bjn Tables of contents and abstracts are available free at the same website.

A study was conducted to estimate the net energy (NE) content of canola meal (CM) and full-fat canola seeds (FFCS) in growing pigs, and to validate the results through a growth trial. The digestible energy (DE) content of the canola products was measured in a digestibility study by the difference method, with diets containing two-thirds of a basal diet of known digestibility and one-third of the canola products. The NE content was estimated by means of a prediction equation based on the DE content and chemical composition of the canola products. The NE was 2.43 and 3.56 Mcal kg-1 DM for CM and FFCS, respectively. For the growth study, 31-kg pigs (18 per treatment) were fed for 35 d with wheat/barley-based diets containing either 0, 5, 10 or 15% FFCS or 0, 7.5, 15 or 22.5% CM. The gain-to-feed ratio was unchanged by the levels of CM or FFCS (P > 0.05), but the highest level of FFCS decreased feed intake (P < 0.001) and thus increased the gain-to-feed ratio (P < 0.05). In conclusion, the NE content was correctly estimated for CM, but slightly underestimated for FFCS. Also, growing pigs can tolerate diets containing up to 22.5% CM or 10% FFCS.Key words: Net energy, growing pigs, canola meal, full-fat canola seeds