Effect of feeding management on neuroendocrine system and colonisation of gut bacteria in neonatal dairy calves

• Author / Creator

  Hromadkova, Jitka

• Neonatal period is challenging for newborn calves as they need to undergo development of immune system and gastrointestinal tract. Stress hormones, glucocorticoids and catecholamines, are elevated in first few days of life and play essential role in neonatal development in newborn calves. In this thesis, two studies were performed to investigate effect of different feeding management on neuroendocrine system and gut bacterial populations. The first study investigated the effect of duration of colostrum feeding management on abundance of active colon and ileum tissue-associated bacteria and expression of neuroendocrine genes in adrenal glands and intestine mucosa. Holstein bull calves were fed colostrum immediately after birth and randomly assigned to different subsequent feeding; whole milk (WM; n=8), mixture of colostrum and milk (CM; n=8) and colostrum feeding (CF; n=8) for 72h with 12h intervals. Samples of adrenal glands, ileum and colon tissues were collected at 75h postpartum. Quantitative RT-PCR was performed to measure expression of neuroendocrine genes in adrenal gland and intestinal tissues as well as abundance of active bacteria associated with intestinal mucosa. The altered expression of these genes in adrenal glands, ileum and colon tissues were observed when calves were under different colostral and milk components feeding strategies. Our results indicate that prolonged colostrum feeding increases the abundance of active tissue-associated Lactobacillus spp. and E. coli in colon of newborn calves. The second study further assessed the effect of delayed colostrum feeding on fecal cortisol concentration and digesta-associated bacteria in the colon and rectum of neonatal calves. Holstein bull calves (n =23) were fed pooled, pasteurized colostrum either immediately after birth (0 h; n = 7); or at six (6h; n = 8), twelve (12 h; n = 8) hours after birth. Rectum and colon digesta and colon tissue were collected at 51h postpartum. Enzyme immune assay and quantitative PCR were used to characterise fecal cortisol level and bacterial abundance, respectively. Results indicate that feeding colostrum 12h postpartum decreased (P < 0.05) fecal cortisol concentration, compared to non-delayed (0h) and 6h delayed colostrum feeding. This thesis is the first to detect and characterize expression of genes involved in neuroendocrine functions and extra-adrenal production of stress hormone in neonatal dairy calves. The findings suggest that different duration and delayed feeding of colostrum can affect neuroendocrine system and bacterial populations which may influence development of immune system and gastrointestinal tract. Outcomes of this study provide fundamental knowledge to establish effective feeding management in dairy industry, which support development of immune system and gastrointestinal tract.

• Subjects / Keywords

  • neonatal development
  • gut bacteria
  • GIT
  • dairy calves
  • neuroendocrine system

• Graduation date

  Fall 2018

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3H98ZW0W

• License

  Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.