TY  - THES
T1  - Impact of Escherichia coli phages as an adjunct to probiotics in modifying chicken gut microbiota
A1  - Mohd Asrore, Mohd Shaufi
LA  - English
YR  - 2017
UL  - http://discoverylib.upm.edu.my/discovery/Record/oai:ethesis.upm.edu.my:12882
AB  - The regulation of antibiotic growth promoters (AGPs) for poultry production in many
countries has increased the need to find an effective alternative. Probiotics are by far
the most recognised alternative to AGPs, and numerous studies have highlighted their
efficacy in chickens. Probiotics are live microorganisms, and they adhere to the
intestinal epithelial cells to exert their beneficial effects on the host. However, this is
often restricted by indigenous gut microbes that compete for adhesion sites and
nutrients. Phage application, which has almost similar mechanisms to those of AGPs,
has been proposed to reduce the competition of probiotics with gut microbiota. At
present, there is a paucity of information on the modulation of gut microbiota by
phages and their influences on probiotic efficacy in chickens. Thus, the main objective
of this study was to investigate the effects of locally isolated phages on the gut
microbiota, and their impact on probiotic efficacy in chickens. The gut microbiota of
chickens was first studied using high-throughput next-generation sequencing (HTNGS)
of 16S rRNA gene amplicons to investigate their diversity and the target bacteria
for modulation. The selected bacteria were then isolated from the chicken gut, and lytic
phages were screened. Four best lytic phages were selected, characterised based on
their morphological, molecular and physiological properties, and prepared as phage
cocktail supplementations for an in vivo chicken trial. The in vivo chicken trial was
conducted to investigate the effects of dietary treatments of phage cocktail at 0.1%
(1ɸ) and 0.2% (2ɸ), 0.1% PrimaLac® probiotic (P) and their combinations (1ɸP, 2ɸP)
on growth performance, serum biochemistry and immunoglobulins, haematological
parameters, ileal villus height and crypt depth, relative organ weights, and gut
microbiota in ilea and caeca based on real-time quantitative Polymerase Chain
Reaction (qPCR) and HT-NGS 16S rRNA gene amplicons of 21 and 35 d chickens.
Escherichia coli was selected as the target bacterium for gut modulation by phages
owing to their consistent presence in the gut. The results from the in vivo chicken trial
showed that birds in the 1ɸP group had significantly (P < 0.05) better body weight
(BW), body weight gain (BWG), and feed conversion ratio (FCR), higher serum total
protein, lower serum triglycerides and higher ileal villus height than the control.
Chickens in the 1ɸP group also had higher (P < 0.05) serum total protein, ileal villus
height, and lower crypt depth than those in the probiotic group. The gut microbiota profiles revealed that 1ɸP supplementation significantly (P < 0.05) reduced E. coli
population, increased (P < 0.001) short chain fatty acid (SCFAs) producers, and
improved (P < 0.001) gene expressions that are related to carbohydrate and amino acid
metabolisms, and nutrient uptake, based on the predicted metagenomes analysis. The
results from this study showed that 0.1% E. coli phage cocktail combined with
probiotics could modulate the gut microbiota and enhance growth performance in
chickens. Thus, the use of phage cocktail with probiotic would be a potential
alternative to AGPs for poultry production.
ER  -