Investigation of the nutritional and functional roles of a microencapsulated blend of botanicals on intestinal health and growth of nursery pigs challenged with F18+ Escherichia coli

Abstract

The study aimed to evaluate the effects of increasing levels of a microencapsulated blend of botanicals (MBB) on the intestinal health and growth performance of nursery pigs challenged with F18+ E. coli. Sixty-four nursery pigs (6.8 ± 0.3 kg) were assigned to four dietary treatments in a randomized complete block design, with initial body weight and sex as blocks, and fed for 28 d in 3 phases. Treatments were a basal diet fed to pigs without F18+ E. coli challenge (NC) and 3 levels of MBB (0.0, 0.1, and 0.2%) in pigs challenged with F18+ E. coli. On d 7 of the study, pigs in challenged group were orally inoculated with F18+ E. coli (1.5 × 1010 CFU). On d 7 and 21 post-challenge, pigs were euthanized to collect jejunal tissues and mucosa. Compared to the NC, 0.0% MBB increased (P < 0.05) relative abundance (RA) of Staphylococcus saprophyticus and reduced (P < 0.05) Streptococcus parasuis at d 7 and 21 post-challenge, respectively. Increasing levels of MBB decreased (linear: P < 0.05) RA of Staphylococcus saprophyticus on d 7 post-challenge. Compared to the NC, 0.0% MBB increased (P < 0.05) jejunal NOD2 and IL-6 expression and decreased (P < 0.05) ZO-1 on d 7 post-challenge. Compared to the NC, 0.0% MBB decreased (P < 0.05) jejunal IL-6, IL-8, and TNF-α and increased (P < 0.05) IgG on d 21 post-challenge. Increasing levels of MBB increased OCLN (linear: P < 0.05) and ZO-1 (linear and quadratic: P < 0.05) on d 7 post-challenge and decreased TLR4 (linear and quadratic: P < 0.05). Compared to the NC, 0.0% MBB decreased (P < 0.05) Ki-67+ on d 7 post-challenge. Increasing levels of MBB increased (linear: P < 0.05) Ki-67+ on d 7 post-challenge and VH:CD on d 21 post-challenge. In overall period, compared to the NC, 0.0% MBB decreased (P < 0.05) average daily gain. Increasing daily MBB intake linearly increased OCLN on d 7 and VH:CD on d 21, and reduced TLR4 and IL-8 on d 21 post-challenge, but exhibiting quadratic effects (P < 0.05) on ZO-1 (optimal at 0.12% of MBB), IgG (optimal at 0.14% of MBB), and G:F during d 7 to 20 and d 7 to 28 (optimal at 0.22% and 0.10% of MBB, respectively). In conclusion, F18+ E. coli challenge negatively modulated the jejunal mucosal microbiota and reduced intestinal morphology and growth of nursery pigs. Supplementation of MBB at 0.10 to 0.14% provided optimal mitigation of the impacts of F18+ E. coli challenge on humoral immunity, intestinal integrity, jejunal morphology, and feed efficiency of pigs.