Selected lignosulfonate fractions affect growth performance, digestibility, and cecal and colonic properties in rats

We determined the effects of lignosulfonate (LS) on nutrient digestibility and on hindgut fermentation characteristics using 80 adult male Sprague-Dawley rats fed a control diet or a diet containing 3% (dry matter basis) of seven selected LS fractions. Lignosulfonate fractions were divided into three categories: two fractionated whole calcium spent sulfite liquors (CaSSL) and one low-molecular-weight permeate of CaSSL designated as WholeLS 1, 2, and 3, respectively; two extracted sodium LS (NaLS) fractions denoted as HighLS 1 and 2 (high percentage of NaLS); and two concentrated sugar solutions designated as LowLS 1 and 2 (low percentage of NaLS). All diets containing LS were less digestible (P < .001) than the control diet. Lignosulfonate treatment had a variable effect on short-chain fatty acid concentration except for LowLS 1, which tended to enhance butyrate concentration. Cecal organ weights were greater (P < .001) for LS treatments, but there was no difference in colonic organ weights. All cecal and colonic pH values, except the cecal pH for HighLS 2, were lower (P < .001) for LS treatment groups. Colonic Bifidobacterium increased (P < .005) with WholeLS 1 and 3 and HighLS 2 treatments. Cecal Lactobacillus levels were increased (P < .001) by WholeLS 1 and 2, LowLS 2, and HighLS 2. Results show that ingestion of selected LS fractions can modify digestive physiology and gastrointestinal tract characteristics of rats.