Fiber-related digestive processes in three different breeds of pigs

The hypothesis examined in this experiment was that, because of intensive selection for greater daily BW gains and efficient utilization of concentrated low-fiber diets, modern pig breeds differ from old local breeds in their physiological ability to respond to soluble dietary fiber. Thus, the old local breeds, Schwaebisch Haellisches Schwein (SH) and Bunte Bentheimer (BB), and a modern crossbred pig (CB) were used in metabolism trials to study fiber-related digestion, including microbial hindgut fermentation, by applying a colon simulation technique (Cositec) and measuring intestinal glucose transport in Ussing chambers. A basal diet or basal plus 20% dried sugar beet pulp (SBP) as a soluble fiber source was fed to 6 pigs/breed in a 2 x 3 factorial arrangement of treatments. Four pigs of each breed per treatment were used for intestinal anatomical measurements at the end of the metabolism trials. The pigs had an initial average BW of 33.9 +/- 3.7 kg. The basal diet was formulated to meet 80% of energy and 100% of nutrient requirements for pigs with 700 g of ADG. Feeding the SBP diet reduced total intestinal tract, but it increased colon length, water-holding capacity of the digesta, and fecal bulk (P < 0.01). The digestibility of OM, CP, and ether extract decreased, whereas that of NDF and ADF increased, by SBP (P = 0.001). Pigs receiving SBP excreted less urinary N and retained more N (P = 0.001). The fecal proportions of undigested dietary and water soluble N increased and those of bacterial and endogenous debris N decreased (P < 0.05) in SBP-fed pigs. The SH pigs had lighter empty cecum weight, shorter colons, and less NDF digestibility than BB and CB pigs (P < 0.05). Fecal N excretion did not differ (P = 0.659) among breeds, but SH pigs excreted more urinary N (P = 0.001) than the other breeds. In Cositec, OM, NDF, and ADF disappearance rates from cecal chyme of SBP-fed pigs increased (P < 0.05) irrespective of pig breed. Cecal chyme of SBP-fed BB pigs produced more VFA with a smaller proportion of propionate and a larger acetate to propionate ratio than chyme of SBP-fed SH and CB pigs. The intestinal epithelial glucose transport was greater for ileal than for jejunal tissues (P < 0.001) but was not influenced by diet and pig breed. In conclusion, the modern and intensely selected pig breed can utilize SBP fiber as efficiently as the old pig breeds under the present experimental conditions.