The Impact of a Sericea Lespedeza Diet on Bifidobacteria in Goat Rumen
Gastrointestinal nematodes in goats have developed resistance to chemical anthelmintics resulting in the need for alternative control strategies. One approach to this problem is the incorporation of condensed tannin- rich (CT) forages that suppress gastrointestinal parasites in goats. In this study, the effect of supplementing goat diets with sericea lespedeza (SL), a high-quality CT-rich forage, on rumen microorganisms was evaluated in goats. A diverse collection of microorganisms is found in the goat rumen. Bifidobacteria are important organisms involved in gastrointestinal tract immunity, however, their presence and modulation in the goat rumen has not been fully investigated. The objective of this study was to evaluate the impact of a diet containing SL on rumen microorganisms, especially Bifidobacteria, in goats. Isolated microbial DNA from rumen samples of goats receiving a diet with SL (n=5) and goats receiving an SL free diet (n=6) were used for detection of Bifidobacteria. The isolated microbial DNA was amplified using 16S rDNA universal bacterial primers. Amplified DNA from goats receiving SL in the diet and control groups by Polymerase chain reaction were used for denaturing gradient gel electrophoresis (PCR-DGGE) analysis of total microbial profile. Genus-specific primers of 16S rDNA for Bifidobacterium were used to amplify the specific DNA sequence. The results of the DGGE analysis showed similar band patterns in the control group compared to the groups receiving the SL diet. A 580-bp Bifidobacterium-specific band was observed in samples from goats fed the SL free diet (P<0.002). Bifidobacterium DNA was not detected in goats fed a diet containing SL. This suggests that dietary tannins may affect the goat's rumen microbial profile. Further, studies are needed to determine the significance of changes in Bifidobacteria on goat health.