Influence of dietary condensed tannins from sericea lespedeza on bacterial loads in gastrointestinal tracts of meat goats

摘要

This research assessed the potential use of a low input forage containing a high amount of condensed tannins (CT) to reduce foodborne pathogens prior to slaughter of meat goats. In a completely randomized design, twenty KikocSpanish intact male kids (BW=19.2pl0.74kg) were fed ground sericea lespedeza [SL; Lespedeza cuneata (Dum-Cours) G. Don; 2 pens], a high-CT legume, or bermudagrass hay [BG; Cynodon dactyon (L.) Pers.; 2 pens], at 75% of daily intake with a corn-based supplement (25% of intake) for 14weeks (n =10 goats/treatment). At the end of the feeding trial, the animals were slaughtered using standard procedures. Immediately after evisceration, rumen and rectal samples were collected to assess bacterial loads and volatile fatty acids in the rumen. Concentrations of rumen volatile fatty acids were significantly different between dietary treatments. Goats fed SL hay had higher (P <0.05) contents of butyric (8.66 vs 7.16mM), isobutyric (1.94 vs 1.44mM), isovaleric (3.03 vs 2.13mM), and valeric (1.43 vs 1.07mM) acids than those fed BG hay; however, the content of acetic acid (78.6 vs 64.4mM) was higher (P <0.05) in the BG-fed groups than in SL-fed groups. Escherichia coli (2.33 vs 1.13 log CFU/g) counts of rumen contents were higher (P <0.05) in the SL-fed group compared with the BG-fed group. However, E. coli counts in feces were not different (P >0.05) between dietary treatments. The high-CT influenced (P <0.05) total plate counts in the feces; and the total plate counts in feces of SL- and BG-fed goats were 4.95 and 6.57 log CFU/g, respectively. The results indicated that high CT in the diet might influence rumen volatile fatty acid composition, but might not reduce the bacterial loads in gastrointestinal tracts of meat goats.