Received: October 28, 2016; Revised: January 3, 2017. Accepted: January 28, 2017. Published online February 1, 2017.
Objective: The effect of flavonoids from alfalfa on the microbial flora was determined using molecular techniques of 16S ribosome deoxyribonucleic acid (rDNA) analysis. Method: Four primiparous Holstein heifers fitted with ruminal cannulas were used in a 4 × 4 Latin square design and fed a total mixed ration (TMR) to which alfalfa flavonoids extract (AFE) was added at the rates of 0 (A, control), 20 (B), 60 (C) or 100 (D) mg per kg of heifer body weight (BW) . Results: The number of OTUs in heifers given higher levels of flavonoid extract (C and D) was higher than for the two other treatments. The Shannon, ACE and Chao indices for treatment C were significantly higher than for the other treatments (P < 0.05). The number of phyla and genera increased linearly with increasing dietary supplementation of AFE (P < 0.05). The principal co-ordinates analysis (PCoA) plot showed substantial differences in the microbial flora for the four treatments. The microbial flora in treatment A was similar to that in B, C and D were similar by the weighted analysis. The richness of Tenericutes at the phylum level tended to increase with increasing AFE (P = 0.10). The proportion of Euryarchaeota at the phylum level increased linearly, whereas the proportion of Fusobacteria decreased linearly with increasing AFE supplementation (P=0.04). The percentage of Mogibacterium, Pyramidobacter and Asteroleplasma at the genus level decreased linearly with increasing AFE (P < 0.05). The abundance of Spirochaeta, Succinivibrio, and Suttonella at the genus level tended to decrease linearly with increasing AFE (0.05 < P < 0.10). Conclusion: Including AFE in the diet of dairy cows may alter the microbial composition of the rumen; however its effect on nutrient digestibility remains to be determined.
Asian-Australasian Association of Animal Production Societies(AAAP)
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