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Effect of Lactose, Inulin, Lactobacillus Acidophilus Fermentation Product, or Dietary Antibiotics on Intestinal Function of Nursery Pigs.
The objective of this study was to determine the effect of lactose (LA), Lactobacillus acidophilus fermentation product (FP: SynGenX®, Diamond V, Cedar Rapids, IA), inulin, and dietary antibiotics on intestinal function of nursery pigs. Forty-nine newly-weaned pigs (ca 21-d of age; initial BW=5.2±0.2 kg), were housed in metabolism crates and randomly assigned to 1 of 7 treatments: 1) control diet (CT); 2) 1 plus 0.1% FP; 3) 1 plus 15% lactose; 4) 3 plus 0.1% FP; 5) 3 plus 3% inulin; 6) 3 plus 0.1% FP and 3% inulin; and 7) 1 plus chlortetracycline (440ppm) and tiamulin-hydrogen-fumarate (39ppm). At d5, pigs were orally given lactulose and mannitol to assess small intestinal permeability. At d15, all pigs were euthanized to assess intestinal morphology. Data were analyzed using pre-planned contrasts to test the effects of antibiotics (7 vs 1; 7 vs 2 and 7 vs 3), LA (3,4 vs 1,2), FP (2,4,6 vs 1,3,5), inulin (5,6 vs 3,4), the interaction between LA and FP (1,4 vs 2,3), and the interaction between FP and inulin (3,6 vs 4,5). There were no differences in lactulose or mannitol recovery, or lactulose:mannitol ratio (P>0.10). Antibiotics tended to decrease villus height (VH) in the jejunum (-80 µm; P =0.065) and decreased VH in the ileum (-107µm; P=0.007) compared to LA. Antibiotics tended to decrease ileum VH (-68µm) compared to FP (P=0.074). There was an interaction between LA and FP in the jejunum (P=0.036) and ileum (P=0.014); LA and FP provided alone increased VH (+64µm: jejunum and +68µm: ileum), compared to the combination of FP and LA or when neither of the products were added. Inulin had no effect in jejunum or ileum VH. Jejunum or ileum crypt depth (CD) did not differ, except for antibiotics that increased CD in the ileum compared to CT (+86µm; P=0.001), FP (+101µm; P<0.001) and LA (+85µm; P=0.002). There was no difference in VH:CD in the jejunum; in the ileum, there was an interaction between lactose and FP (P=0.009); LA and FP provided alone increased VH:CD (+0.34), compared to the combination of FP and LA, or when neither of the products were added. In the ileum, pigs fed antibiotics had decreased VH:CD compared to FP (-0.61; P=0.001) and LA (-0.66; P=0.002). In conclusion, although none of the products affected small intestinal permeability, lactose and FP alone (but not in combination) increased villus height of weaned pigs.