Fruit and vegetable fiber fermentation by gut microflora from canines

The objective of this study was to assess fermentability by canine gut micr oflora to include short-chain fatty acid (SCFA) production, organic matter (OM:) disappearance, and gas production of vegetable and fruit fiber source s compared to fiber standards (psyllium, citrus pectin, and Solka Floc). Fi ber sources included apple pomace, carrot pomace, flaxseed, fruit blend (mi xture of peach, almond, nectarine, and plum), grape pomace, pea hulls, pist achio, and tomato pomace. Substrates were fermented in vitro for 4, 12, and 24 h with fecal flora obtained from three healthy dogs. Citrus pectin had the highest OM disappearance, SCFA production, and gas production at all ti mes of fermentation; psyllium was intermediate and Solka Flee was lowest. A wide variation in fermentability was noted among the vegetable and fruit f iber sources. Apple pomace, carrot pomace, and flaxseed had the greatest fe rmentability as assessed by OM disappearance. Pea hulls and tomato pomace h ad intermediate OM disappearances, and fruit blend, grape pomace, and pista chio were poorly fermented. Carrot pomace produced the largest amounts of g as and SCFA. Apple pomace produced high concentrations of gas but intermedi ate concentrations of SCFA. Pea hulls and tomato pomace produced intermedia te concentrations of gas and SCFA, whereas flaxseed, fruit blend, grape pom ace, and pistachio produced low amounts of these fermentation products. For all substrates collectively, OM disappearance was highly correlated with b oth gas production (r(2) = 0.782 and 0.723 for 12- and 24-h values, respect ively) and SCFA production (r(2) = 0.737 and 0.738 for 12- and 24-h values, respectively). In general, OM disappearance, gas production, and SCFA prod uction were related to the insoluble:soluble fiber ratio in the samples; as the insoluble:soluble ratio decreased (increased soluble fiber), the OM di sappearance, gas production, and SCFA production increased.