Investigation of health promoting effects of Manitoba-grown red osier dogwood as an alternative to antibiotics in nursery pig production

Abstract

The objective of this study was to investigate the health-promoting effects of red osier dogwood extract as an alternative to antibiotics, in weaned piglets challenged with enterotoxigenic Escherichia coli. Twenty-eight weaned piglets, genetically susceptible to ETEC, were individually assigned to one of four dietary treatments in a completely randomized design. The experimental diets were, negative control (NC), corn-wheat soybean meal diet with no additives; positive control (PC), NC plus antibiotics; ROD1, NC plus 0.1% ROD extract; ROD2, NC plus 0.2% ROD extract. Piglets were orally challenged on d 7 with ETEC F4. Feed disappearance, body weight, fecal score, and temperature were recorded, and blood samples were taken before and after the challenge. On d 14, the piglets were euthanized to collect intestinal tissue and colon digesta samples. Data were analyzed with the MIXED procedure of SAS. NC piglets tended to have a higher average daily gain post-inoculation than ROD1 or ROD2. The fecal score of PC group tended to and was significantly lower than for ROD1 or ROD2 piglets on d 0 and 3 post-inoculation (dpi), respectively. On 0 dpi, ROD1 piglets had significantly higher body temperature than those fed PC or ROD2. The cytokine interleukin-10 tended to be higher in ROD2 piglets as compared to NC group, pre-inoculation. Post-inoculation, malondialdehyde levels tended to be lower in ROD2 group than in ROD1 group. The intestinal mRNA gene expression of catalase enzyme was significantly higher in ROD1 group than in NC group. The gene expression of IL-10 tended to be lower in ROD1 than in NC piglets. Moreover, for IL-6, PC group had significantly lower and ROD2 had a lower tendency of gene expression than NC group. Microbial DNA results showed Bifidobacterium was significantly lower in ROD2 and tended to be lower in ROD1 and PC as compared to NC piglets. Also, E. coli F4 tended to be lower in the PC group as compared to the NC group. In conclusion, red osier dogwood extract supplementation might have some health-promoting effects on gut health and oxidative status of ETEC challenged weaned piglets but is not comparable to antibiotic growth promoters.