ACTA VETERINARIA ET ZOOTECHNICA SINICA ›› 2019, Vol. 50 ›› Issue (10): 2041-2052.doi: 10.11843/j.issn.0366-6964.2019.10.010

• ANIMAL NUTRITION AND FEEDS • Previous Articles     Next Articles

Effects of Bacillus Subtilis Supplementation into Milk Replacer on the Development of Gastrointestinal Tract of 7-28 Day-old Hu Lambs

ZHENG Chen1, LI Fadi2,3, LI Fei2, ZHOU Juwang1, DUAN Pengwei1, LIU Huihui1, FAN Haimiao1, ZHU Weili1, LIU Ting1*   

  1. 1. College of Animal Science and Technology, Gansu Agricultural University, Lanzhou 730070, China;
    2. State Key Laboratory of Grassland Agro-ecosystems, Key Laboratory of Grassland Livestock Industry Innovation of Ministry of Agriculture and Rural Affairs, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, China;
    3. Engineering Laboratory of Mutton Sheep Breeding and Reproduction Biotechnology in Gansu Province, Minqin 733300, China
  • Received:2019-04-18 Online:2019-10-23 Published:2019-10-23

Abstract: The purpose of this study was to investigate the effects of Bacillus Subtilis supplementation into milk replacer on the development of gastrointestinal tract of 7-28 day-old Hu lambs. Thirty 7 day-old Hu male lambs(double lambs) were chosen and divided into 2 groups randomly, fifteen lambs in each group and each lamb as a repeat. Lambs in the 2 groups were fed milk replacer with 0 and 0.2% Bacillus Subtilis, respectively. The test lasted for 21 days. Eight lambs were selected from each group randomly and slaughtered at 28 day-old. The weight and net weight of content in the each stomach chamber and each intestinal segment, the length of the intestinal tracts were measured, and the relative weight, relative length and content distribution were calculated. The tissue samples from fundus gland region of the abomasum, the middle part of duodenum, jejunum and ileum were fixed in paraformaldehyde to analyse the histomorphology, and the apoptotic rate of small intestinal epithelial cells was detected. And the mRNA expression of occludin, ZO-1 and claudin 1 in duodenum, jejunum and ileum mucosa were measured. The results showed that:1) Bacillus Subtilis significantly decreased the duodenum index (percentage to body weight, P=0.037), relative length of jejunum (percentage to intestinal tract length, P=0.009) and villus width of duodenum of 7-28 day-old Hu lambs (P=0.001), and increased relative length of colon (percentage to intestinal tract length, P=0.012), relative weight of jejunum content (percentage to intestinal tract content weight, P=0.003), villus height and crypt depth of ileum (P=0.010, P=0.034); 2) Bacillus Subtilis significantly increased the mRNA expression of ZO-1 protein in duodenum mucosa of lambs (P=0.012), in addition, there was a tendency that Bacillus Subtilis up-regulated mRNA expression of oocludin protein in ileum mucosa (P=0.053) and reduced the apoptotic rate of ileum epithelial cells of lambs (P=0.079); 3) Bacillus Subtilis did not affect the relative weights of stomach,intestine segments (percentage to body weight, percentage to stomach weight, percentage to intestinal tract weight and percentage to gastrointestinal tract weight), relative weights of content of stomach and intestinal tract (percentage to body weight, percentage to stomach content weight, percentage to intestinal tract content weight and percentage to gastrointestinal tract content weight), gut relative lengths (percentage to intestinal tract length), histomorphology of abomasum and intestinal tract, mRNA expression of occludin, ZO-1 and claudin 1 proteins in intestine mucosa, and epithelial cells apoptosis rate of other parts of small intestine (P>0.05). It indicates that Bacillus Subtilis almost does not significantly influence the gastrointestinal tract developments of 7-28 day-old Hu lambs, but improves the barrier function of small intestine and decreases the apoptotic rate of small intestinal epithelial cells, beneficial for maintaining normal structure and function of intestinal tract.

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