The Impact Of Diet On Goat Rumen Microbes And Innate Immune Gene Expression
Abstract
Gastrointestinal nematodes in goats have developed resistance to chemical anthelmintics, resulting in the need for alternative control strategies. One approach is incorporation of Sericea Lespedeza (SL) as high quality forage that suppresses these parasites in goats due to its high condensed tannin (CT) content. However, little is known about its effect on rumen microorganisms and innate immunity in goats. A diverse collection of microorganisms is found in the goat rumen and Bifidobacteria is one of the important organisms in the immunity, yet its presence in the goat rumen is not fully studied. The objective of this study was to evaluate the impact of a diet containing SL on goat rumen microorganisms, Bifidobacteria and on the goat's innate immune gene expression. Microbial DNA was isolated from rumen samples using the QIAamp DNA kit (Qiagen, USA) to compare rumen microbes and Bifidobacteria in control group and group that received SL in diet. The isolated microbial DNA was amplified using 16S rDNA universal bacteria and Bifidobacterium genus specific primers to compare between goats that received SL in diet and control groups by PCR/ DGGE analysis. Blood was collected for immune markers and pro-inflammatory cytokines profiling, as well as total serum protein analysis. Serum was extracted and used for evaluation of secretion of pro-inflammatory cytokines (TNFa, IFNr, GCSF, GMCSF, IL-1a, IL8, IP-10 and RANTES) using a commercial Enzyme-linked immunosorbent assay kit. Analysis of DGGE results showed different band patterns between control and animals that received SL diet. A 580-bp Bifidobacterium specific band was observed in control group and no band was detected in goats fed a diet containing SL (P <0.002). Gene expression profiling of innate immunity markers (CD-14, TLR-2, TLR-4, IL-10, IL-8, IL-2, INF-γ, and TNF-α) were found to be higher in treatment animals compared to controls. Sericea Lespedeza diet affected 3 the secretion of pro-inflammatory cytokines by increasing their level in serum (p < 0.0002), except for IL-8, and RANTES in goats fed SL in the diet were decreased (p < 0.0001). This suggests that tannins from SL affect the goat's innate immune response and rumen microbes.