Effects of a Compound Microbial Agent on Weight-gain, Gastrointestinal Villi and Flora of Pigs at Fattening Stage

  Objective  Effects of a compound microecological bioagent on the weight-gain, gastrointestinal villi and micro-flora in pigs at end of growth period were studied．

  Methods  Three-hundred 60-day-old, weighing 25 kg, fattening pigs were randomly divided into control and treatment groups with 15 replicates of 10 pigs in each group. The treatment pigs were fed the forage diet supplemented with a microecological agent, while control with aseptic water. Daily feed-intake and weight-gain of the individual pigs were recorded for 90 d. Ratio of feed consumption/weight-gain was measured on the 15^th, 30^th, 60^th, and 90^th day during the feeding period. At end of the experiment, gastric and colon mucus of 18 randomly selected pigs from each group were collected for the Illumina MiSeq analysis on 16S rRNA gene and the HE-staining on gastrointestinal villi for a microscopic examination.

  Results  The average daily weight-gain of the treatment pigs significantly increased over control (i.e., 35.53 g increase at P＜0.05) with 10 percent reduction on feed-consumption/weight-gain ratio at P＜0.05. The 16S rRNA sequencing showed a significantly higher abundance of Lactobacillus in the gastrointestinal tracts of treatment pigs (averaging 67.81%) than that of control (averaging 13.54%) at P＜0.05, but that of Clostridium difficile (i.e., 4.51%) significantly lower than that of control (i.e., 5.55%) at P＜0.05. In the colon mucus, the genus abundance of Lactobacillus in treatment pigs (i.e., 6.51%) was significantly higher than that in control pigs (i.e., 3.17%) at P＜0.05, but C. difficile (i.e., 2.32%) significantly lower than that of control (i.e., 3.73%) at P＜0.05. The supplementation of the compound microbial agent also significantly increased the length and density of gastrointestinal villi in the treatment pigs (P＜0.05).

  Conclusion  The compound microecological bioagent significantly improved the weight-gain and increased the flora of beneficial bacteria as well as the gastrointestinal villi in the guts on pigs at fattening stage prior to slaughtering.