Effects of Mannan Oligosaccharides and Lactobacillus Mucosae on the Growth Performance and Immune Response of Weanling Pigs Challenged with Escherichia coli Lipopolysaccharides

Previously, dietary mannan oligosaccharides (MOS) increased fecal abundances of Lactobacillus mucosae (LM), which was positively correlated with circulating IgA concentration. To determine the effects of feeding MOS and LM as prebiotic and probiotic sources in weanling pigs under immune challenge, 96 pigs (BW = 5.88 kg; d 23 post-farrowing) were randomly allotted to 16 experimental pens with a 2 × 2 factorial arrangement of treatments (4 pens per treatment; mixed gender). Corn-soybean-meal based diets (without plasma or antibiotics) with or without 0.1% yeast-derived MOS (Saccharomyes cerevisiae) were randomly assigned to pens and 10⁹ cfu/pig LM broth or a control broth were top-dressed daily. Pigs were given 1 of the 4 dietary treatments (control, MOS, LM, and MOS+LM) in phase-1 and phase-2 (d 0 to 7 and d 7 to 21 post-weaning, respectively) and a common diet during phase-3 (d 21 to 35 post-weaning). On d 14, all pigs were challenged with 100 μg/kg BW of Escherichia coli lipopolysaccharides (LPS) via i.p. injection. Feed disappearances and pig BW were measured weekly. Blood samples were collected weekly and on d 1 and 3 post-LPS-challenge. Data were analyzed using PROC GLIMMIX of SAS. From d 0 to 14, feeding LM decreased (P < 0.05) G:F. From d 14 to 21, G:F (g/kg) in LM (715) was greater compared to MOS+LM (P < 0.05; 600) and control (P < 0.10; 615), but was not different (P > 0.10) from MOS (674). After removal of treatments (d 28 to 35), G:F was decreased (P < 0.05) in the LM treatment group. Feeding MOS vs. non-MOS treated diets increased IgG (mg/mL) on d 1 and 3 post-LPS-challenge (P < 0.05; 3.15 and 4.39 vs. 2.58 and 3.34, respectively) and on d 14 and 21 post-weaning (P < 0.10; 3.68 and 4.56 vs. 2.94 and 3.72, respectively). On d 21, serum IgA concentrations (mg/mL) were greater (P < 0.05) in LM (0.416) compared to MOS (0.341) and MOS+LM (0.342), and tended to be greater (P < 0.10) in LM vs. control (0.347). Using d 0 (P < 0.05) IL-1β concentration as a covariate, circulating IL-1β in control and MOS+LM pigs increased (P < 0.05) on d 1 post-LPS-challenge, but did not change (P > 0.10) in MOS and LM groups. In conclusion, feeding LM alone improved feed efficiency during the first week of LPS-challenge; additionally, feeding LM and MOS may have beneficial effects relative to immune biomarkers.