Lysozyme Effects On Rectum Flora Diversity Of Perinatal Cows Bingbing XIE

According to the different physiological characteristics and breeding scheme of cows, the entire lactation period is divided into six stages. The perinatal period is from the late of dry period (prenatal 3 weeks) to the early of lactation period (after 3 weeks). Influenced by physiological factors, the perinatal cows feed intake declines, so the feed intake is insufficient to meet the increasing energy demands of lactation, and cause the energy negative balance. Serious energy negative balance of cows can cause ketosis and fatty liver disease, and decrease the immunity and fecundity, which can cause postpartum paralysis, mastitis, retained placenta, endometritis and so on, brings the serious economic loss to the dairy industry. The gastrointestinal tract normal flora is closely related to the nutrition, metabolism and immune. The physiological changes affect the gastrointestinal tract flora, to reduce this effect has important significance. This experiment through feeding lysozyme to the cows in perinatal stage, using ERIC-PCR fingerprint and RFLP classification technology, analysis the lysozyme effects on the intestinal flora diversity of perinatal cows, and explore the lysozyme adjusts intestinal flora of perinatal cows. The experiment divide the nine cows into three groups randomly, Ⅰ group is the control group(normal feeding group), Ⅱ group is the one cow feed 2 g lysozyme in addition every day, Ⅲ group is the one cow feed 4 g lysozyme in addition every day. The rectal feces collect at the 21 day of prenatal、14 day of prenatal、7 day of prenatal、calving day、7 day of postpartum、14 day of postpartum and 21 day of postpartum. ERIC-PCR fingerprint analysis separately for each group, and find out the main strip, clone and recycle to the strip, use the two kinds of restriction enzymes, HinfI and HhaI, to analysis the strip by RFLP, sequence the main OTU. The results are summarized as follows:1. ERIC-PCR fingerprints analysis shows that:the cows’ rectum flora structure similarity of the three groups, the control group and 4 g lysozyme group are similarity, but compared with 4 g lysozyme group the similarity is low. To analysis the perinatal cows’ rectum flora diversity of three groups, the prenatal rectum rectum flora diversity is greater than the postpartum. The rectum flora diversity of the feeding 4 g lysozyme group in calving day is increased significantly and obvious difference with the control group (P<0.05). Shows that perinatal cows" rectum flora is constantly changing on the perinatal, and lysozyme can influence the bacterial diversity of the cows’ rectum flora.2. Recycle the main strips on the ERIC-PCR fingerprint of three groups, and clone the main strips, classify and sequence. The results show that:the main flora of three groups has a same stripe (about 600 bp), the clone number of OTU is that the control group is 32, feeding 2 g lysozyme group is 21 and feeding 4 g lysozyme group is 25, so after feeding lysozyme the number of bacteria sequence in the main stripe has decreases; the sequencing results show the main containing of the same stripe is Bacteroides. The control group and feeding 2 g lysozyme group have other main stripe (about 350 bp), feeding 4 g lysozyme group has a difference stripe (about 500 bp). Compared with three groups of sequencing results of main OTU, feeding 4 g lysozyme group increases the proportion of Ruminococcus albus、Prevotella、Alistipes and unknown flora, and reduces the proportion of Enterococcus faecalis. Conclusion, lysozyme has not changed the advantage bacterium of rectum flora, but by dissolving some bacteria and changing the composition proportion of rectum flora to regulate intestinal flora.