261 Functional roles of a microencapsulated blend of botanicals on jejunal mucosal immunity and growth of nursery pigs challenged with F18+Escherichia coli.

Abstract The objective of this study was to test the effects of increasing levels of a microencapsulated blend of botanicals (MBB) against an F18+E. coli challenge on mucosa-associated microbiota, mucosal immunity, and morphology in the jejunum of nursery pigs. Thirty-two nursery pigs (6.8 ± 0.3 kg) were assigned to 4 dietary treatments in a randomized complete block design, with initial body weight and sex as blocks, and fed for 28 d in 3 phases (7/13/8 d, respectively). Four dietary treatments were the negative control (NC, receiving a corn-soy basal diet) and the 3 treatments (basal diet supplemented with 0.0, 0.1, and 0.2% of MBB). On d 7, pigs (except for NC) were orally inoculated with F18+E. coli (1.5 × 1010 CFU). On d 28, pigs were euthanized to collect jejunal tissue for histology and mucosa for jejunal mucosal immunity analysis. Growth performance was measured. Data were analyzed using SAS MIXED procedure and polynomial contrasts were conducted to evaluate linear and quadratic effects in challenged groups with SAS RSREG procedure. The 0.0% MBB decreased (P < 0.05) the relative abundance (RA) of Streptococcaceae in the jejunal mucosa compared with NC. Increasing levels of MBB quadratically changed (P < 0.05) the RA of Erysipelotrichaceae (max: 1.85 at 0.09% MBB) and Streptococcaceae (max: 2.35 at 0.08% MBB). The 0.0% MBB decreased (P < 0.05) the relative expression of TLR4 in the jejunum compared with the NC. Increasing levels of MBB both linearly and quadratically changed (P < 0.05) TLR4 (max: 0.9 at 0.07% MBB). The 0.0% MBB decreased (P < 0.05) TNF-α, IL-6, and IL-8 in the jejunum, whereas 0.0% MBB increased (P < 0.05) IgG compared with the NC. Increasing levels of MBB linearly increased (P < 0.05) IL-8 in the jejunum and quadratically changed (P < 0.05) ZO-1 in the jejunum (max: 1.4 at 0.08% MBB). The 0.0% MBB tended to decrease (P = 0.075) villus height in the jejunum compared with the NC. Increasing levels of MBB linearly increased (P < 0.05) villus height to crypt depth ratio in the jejunum. The 0.0% MBB decreased (P < 0.05) body weight on d 14 and gain-to-feed ratio from d 7 to 14 compared with the NC. Increasing levels of MBB both linearly and quadratically changed (P < 0.05) gain-to-feed ratio from d 7 to 20 (max: 0.9 at 0.10% MBB). In conclusion, F18+E. coli challenge negatively modulated the jejunal mucosa-associated microbiota and impaired intestinal morphology and growth performance of nursery pigs. Supplementation of MBB at a range of 0.07 to 0.10% provided the optimal mitigation from the negative impacts of F18+E. coli challenge on humoral immunity, intestinal integrity, jejunal morphology, and feed efficiency of nursery pigs.