Study on the Changes of Rumen Fungal Flora in Dairy Cows with Different Ratios of Concentrate-to-roughage Diet

PurposeTo study the changes of rumen fungal flora in dairy cows with different ratios of concentrate-to-roughage diet.

MethodTwenty four Chinese Holstein cows with the same health, similar body weight, the same parity, and about 3 weeks postpartum were randomly divided into two groups, each group with 12 repetitions. The groups were HC that was fed high ratio of concentrate-to-roughage (60∶40) and LC group that was fed low ratio of concentrate-to-roughage (40∶60), the test period was 45 d. Rumen fluid was collected through the mouth, and the rumen fungal flora of dairy cows was analyzed by ITS high-throughput sequencing technology.

Result(1) The number of OTUs in the HC group was extremely significant lower than that in the LC group (P<0.01); the Ace and Chao1 indices in the HC group were extremely significant lower than those in the LC group (P<0.01), while the Simpson index was significantly lower than that in the LC group (P<0.05). (2) At the level of phylum, the abundance of Ascomycota and Basidiomycetes in the HC group was extremely significantly higher than that in the LC group (P<0.01), while Mortierellomycota was extremely significant lower than that in the LC group (P<0.01). (3) At the level of genus, the abundances of five species yeast and Piromyces, Neocallimastix, Pleospora, Caecomyces which are related to degraded fiber were extremely significant (P<0.01) or significantly (P<0.05) higher than those in the LC group, however, the abundances of Orpinomyces, Cyllamyces, Anaeromyces, Aspergillus and Candida decreased extremely significant (P<0.01）or significantly（P<0.05).

ConclusionThe diversity index and structural changes of the fungal flora can be seen as the concentration of concentrate in the diet increasing, the environment in the rumen changes, which affects the growth and reproduction of rumen microbes in dairy cows, the abundance of fiber degradation fungi in the rumen of dairy cows showed different degrees of increase or decrease. However, with the addition of concentrate in the diet, the growth of yeasts in the rumen of dairy cows is promoted, and the rumen microflora is changed, which ultimately affect the rumen fermentation performance of dairy cows.