Feed Strategy - July 2018 - 26
26 ❙ FeedStrategy
become super shedders in a large proportion - up to 96
percent versus 5 to 10 percent in the general population."
The next step will be to determine flock sensitivity
through its intestinal flora profile as early as possible.
The Tours lab is focused on finding the "good bacteria,"
which, in the low shedders' microbiome, fights against
"We'll be able to propose a kind of "bacterial cocktail," which will act as a barrier against Salmonella and
confirm the best ways to administrate it," Velge said. This
cocktail will be generally administered as a feed additive
in the feed and, if they are used to induct a "good flora" as
soon as the hatchery, they may also sprayed it on the eggs,
similar to some vaccines.
"Good health practices are and will stay the first line [of
defense] against infection. But it is not that easy to control
all farm hygiene precautions day after day," he noted.
Phages and defensins in the
fight against Salmonella
In the context of worldwide growing antibiotic resistance threat, the potential of bacteriophages might be a
novel and innovative strategy to fight this critical issue.
Broiler respiratory tracts: a route
for Salmonella?: www.WATTAgNet.
"Phages are ancient arms against bacteria as they
aim precisely at one bacteria strain," says Catherine
Schoulder, Inra researcher specialized in those bacterial
viruses. "With antibiotic development, the occidental
world had forgotten about them, but Eastern and Central
European countries continued their research and are now
even able to propose commercial solutions, which we
must evaluate. Science and regulation will play a part in
their role, but I'm quite sure phages might be more widely
Researchers have determined that super-shedder
birds excrete as much as 1 million Salmonella
bacteria in one gram of their manure. Philippe Velge
used in poultry future. Now, the scientific community is
active to constitute phage libraries and to test phages to
be sure no resistance or environmental damage will occur
prior to any commercial launch."
Phages can be administered on the drinking water or
sprayed in the building or even injected.
Small peptides, defensins, are another new idea, but
"It is a longer-term solution," said Schoulder. "A lot of the
work is [still] in front of researchers to formulate commercial
solutions and be sure of their stability. Probably, they will be
administered to the birds through their drinking water."
Defensins are small cysteine-rich proteins with antimicrobial action. Extraction and purification from bone
marrow of AvBD2 and AvBD7 has shown their potential
as they have a wide antimicrobial spectrum even against
multi-resistant bacterial strains.
AvB7 has been tested on lethal Salmonella-infected
mice and helped them survive. However, the mode of actions of those defensins is under scrutiny, as they seem
to stimulate macrophages to produce other antimicrobial
components as cytokines.
Transposition at an industrial scale has not been
achieved but, here again, farmers might be optimistic. ◼
Yanne Boloh is a French freelance journalist and a long-time contributor to WATT Global Media's feed publications.
She may be reached at firstname.lastname@example.org.
www.WATTAgNet.com ❙ July 2018