Studies were carried out with six barrows (initial BW 50kg) to determine the effect of two fiber sources on the apparent ileal and fecal N and amino acid digestibilities and bacterial N excretion in feces. The pigs, fitted with a simple Tcannula at the distal ileum, were fed three cornstarch-based diets formulated to contain 16% CP from soybean meal according to a repeated 3x3 Latin square design. Diet 1 did not contain additional fiber. Diets 2 and 3 contained 10% powdered cellulose and 10% barley straw (ground through a 2-mm mesh screen), included at the expense of cornstarch, resptively. The pigs were fed 900g at each meal twice daily, 0800 and 2000. Feces were collected for 48h after a 1O d adaptation period. Thereafter, ileal digesta were collected for 24h. Chromic oxide was used as a digestibility marker. With the exception of leucine, the inclusion of fiber did not affect (P>.OS) the ileal digestibilities of the indispensable amino acids. The values for the average of the ileal digestibilities of the indispensable amino acids were 85.3, 82.9, and 83.2% for diets 1, 2, and 3, respectively. On the other hand, the inclusion of fiber decreased (P<.05) the fecal digestibilities of all the indispensable amino acids. The values for the average of the fecal digestibilities of the indispensable amino acids were 91.7, 87.4, and 89.1% for diets 1, 2, and 3, respectively. These decreases resulted from an increase (P.05) in the excretion of bacterial N, which was measured using 2, 6-diaminopimelic acid as a marker. In conclusion, as measured with the ileal analysis method, the inclusion of fiber had little effect on the digestible

Freeze-dried ileal effluent (1% wt/vol) from cannulated pigs fed rice-based diets with the inclusion of either animal protein (CON), animal protein plus potato starch (PS), animal protein plus sugar beet pulp (SBP), or animal protein plus wheat bran (WB) was incubated anaerobically at pH 6.0 in fermenters containing 5% (wt/vol) fecal slurry comprising mineral salts medium and 50 g/L of fresh feces from pigs fed the same diets as the cannulated pigs. Samples were collected from the fermenters at 0, 2, 4, 12, 24, and 48h during in vitro fermentation for measuring nonstarch polysaccharides (NSP), starch, and short-chain fatty acids (SCFA). Results showed that the major SCFA produced were acetate, propionate, and butyrate. The inclusion of soluble dietary fiber (diet SBP) caused the highest concentrations of acetate, propionate, butyrate, and total SCFA, whereas the increase in the production of propionate resulting from the addition of insoluble dietary fiber (diet WB) only occurred at the initial stages during 48h in vitro fermentation. At all sampling occasions (except for 4h), the levels of butyrate were increased (P<0.01) by resistant starch compared with fiber sources, showing that a higher level of butyrate can be achieved through microbial fermentation by potato starch. Lowered (P<0.05) butyrate concentrations were observed with diet WB during in vitro fermentation. With the inclusion of fiber sources, the energy originating from SCFA was similar to that from NSP disappearance, whereas the values were lower (P<0.05) from NSP disappearance than for SCFA generated without fiber sources supplemented. We conclude that more substrate is available in ileal effluent with the addition of soluble dietary fiber, and an increased level of butyrate could be achieved through microbial fermentation by resistant starch.

A repeated 4✕4 Latin square design was conducted with eight ileal cannulated castrated pigs to investigate the effect of source of dietary fibre and starch on ileal and faecal microflora and short-chain fatty acid concentrations. Four experimental diets based on cooked rice were supplied with one of two fibre-rich sources (sugar-beet pulp, S; wheat bran, W) and another two diets were prepared with (P) or without (C) potato starch. The experimental periods were 14 days, consisting of 7 days of adaptation to each diet, followed by 4 days of collection of ileal digesta and 3 days of collection of faeces. Ileal digesta were collected daily in a randomized order 0 (just before feeding the morning meal), 2, 4, 6 and 8h after feeding the morning meal. Fresh faecal samples were also collected. Ileal pH was lower in pigs given diet P, 2 and 4h after feeding, respectively. For all four diets ileal pH reached a minimum 4h after feeding. Faecal pH was higher for diets P and W compared with diets C and S. The highest density of ileal coliform bacteria was found 4h after feeding for all diets. Compared with other diets, the inclusion of potato starch resulted in an increased density of ileal enterococci at 0h and an increased density of ileal lactic acid bacteria and lactobacilli, 2 and 6h after feeding, respectively. The density of ileal enterococci reached a maximum 4h after feeding for all diets. With the exception of 8h after feeding, when a higher density of total anaerobes was observed for diet P, no significant differences were seen in the populations of yeasts and total anaerobes between the experimental diets. The concentration of formate in the ileum was high, while low concentrations of acetate, propionate and butyrate were observed for all diets. A lowered level of acetate was found for diet S on all sampling occasions. On a dry-matter basis, the counts of various faecal bacteria were increased by the inclusion of the fibre sources, and a higher level of faecal butyrate was found with the inclusion of potato starch or the fibre sources as compared with diet C, whereas no significant effects on the counts of various bacteria were observed with potato starch supplementation. Overall, the present results indicate that the addition of dietary fibre to pig diets resulted in an enhanced microbial fermentation.

The present study was undertaken to study the effect of dietary fibre on gastric microflora, and short-chain fatty acids (SCFA) concentrations at different time after feeding in gestating sows. Three experimental diets consisting of two dietary fibre-rich diets and one concentrated, low dietary fibre diet (C) were used. One fibre-rich diet contained soluble dietary fibre from sugar beet pulp (S) and the other contained insoluble dietary fibre from wheat bran (W). The experiment was carried out as repeated 3×3 Latin squares with six gastric-cannulated gestating sows fed one of the three experimental diets, with experimental periods of 7 days, comprising 3 days of adaptation to each diet, followed by 4 days of collection of gastric digesta. The gastric digesta were evacuated once daily through the gastric cannula in a randomized order 0.5, 1, 2, 3, 5 and 15.5h after feeding the morning meal. The evacuated gastric digesta were quantified and a representative sample collected for measuring pH, dry matter (DM) content, SCFA, density of various bacterial populations (including coliform bacteria, lactic acid bacteria, lactobacilli, enterococci and yeasts), adenosine 5’-triphosphate (ATP), and adenylate energy charge (AEC). With all three diets, gastric pH was highest at 0.5h after feeding, and then fell gradually with increasing time (especially between 0.5 and 2h) after feeding. The changing trend of pH with the three diets was not significantly different. The total counts of coliform bacteria, lactic acid bacteria, lactobacilli, enterococci and yeasts were also highest at 0.5h after feeding, in agreement with gastric pH values. The population of coliform bacteria with diet S decreased significantly compared with diet C or diet W (P<0.05). The concentration of gastric ATP was highest at 15.5h after feeding. The level of acetate had the lowest value at 0.5–1h with diets S and C, but at 2h with diet W. In conclusion, gastric pH was unstable at different time after feeding, and was highest at 0.5h after feeding. The highest populations of various gastric bacteria were found at 0.5h after feeding, irrespective of type of diet. As gastric pH increased, gastric microbial activity was inhibited. The populations of lactic acid bacteria and lactobacilli with the insoluble dietary fibre were always higher than with the soluble dietary fibre at all times after feeding. Soluble dietary fibre increased the level of acetate.