Effects of Dietary Non-Fibrous Carbohydrate (NFC) to Neutral Detergent Fiber (NDF) Ratio Change on Rumen Bacteria in Sheep Based on Three Generations of Full-Length Amplifiers Sequencing

• Main Authors: Xuanxuan Pu, Xuefeng Guo, Khuram Shahzad, Mengzhi Wang, Chenyu Jiang, Junfeng Liu, Xiuping Zhang, Sujiang Zhang, Long Cheng
• Format: Article
• Language: English
• Published: MDPI AG 2020-01-01
• Series: Animals
• Subjects: ruminal microbes; nfc/ndf ratio; amplifier sequencing
• Online Access: https://www.mdpi.com/2076-2615/10/2/192

The study was conducted to investigate the effects of dietary NFC/NDF ratio change on rumen bacteria in sheep. Twelve Karakul sheep were assigned randomly into four groups fed with four dietary NFC/NDF ratios of 0.54, 0.96, 1.37, and 1.90 and they were assigned into groups 1, 2, 3, and 4, respectively. The experiment was divided into four periods: I (1&#8722;18 d), II (19&#8722;36 d), III (37&#8722;54 d), and IV (55&#8722;72 d). In each period, the first 15 d were used for adaption, and then rumen fluid was collected for 3 d from each sheep before morning feeding. The fluid was analyzed with three generations of full-length amplifiers sequencing. Results showed that the bacterial diversity of group 4 was decreased in period III and IV. At the phylum level, Bacteroidetes (37&#8722;60%) and Firmicutes (26&#8722;51%) were the most dominant bacteria over the four periods. The relative abundance of Bacteroidetes, Firmicutes, Tenericutes, and Spirochaete changed with dietary NFC/NDF ratio change over the four periods, but there was no difference among groups over the four periods (<i>p</i> &gt; 0.05). At the genus level, unidentified-<i>Lachnospiraceae</i> was the dominant genus, and its relative abundance in group 3 was high during the period I and III (<i>p</i> &lt; 0.05). The relative abundance of <i>Mycoplasma</i> in group 4 was high in the period I and II (<i>p</i> &lt; 0.05). The relative abundance of <i>Succiniclasticum</i> was high in group 2 of period II (<i>p</i> &lt; 0.05). At the species level, the relative abundance of <i>Butyrivibrio-fibrisolvens</i> was found to be high in group 3 during periods I and III (<i>p</i> &lt; 0.05). The main semi-cellulose-degrading bacteria and starch-degrading bacteria were low, and there was no significant difference among groups over four periods (<i>p</i> &gt; 0.05). Taken together, the dietary NFC/NDF ratio of 1.90 decreased the diversity of bacteria as a period changed from I to IV. While the main phylum bacteria didn&#8217;t change, their relative abundance changed with the dietary NFC/NDF ratio change over the four periods. The most prevalent genus was unidentified-<i>Lachnospiraceae,</i> and its relative abundance was higher in dietary NFC/NDF ratio of 1.37 than other groups. Similarly, the main cellulose-degrading species was higher in the treatment of dietary NFC/NDF ratio of 1.37 than other groups.